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necessary for judging the vessel's strength and safety.
1.21.2 Additional documents and drawings may be required, if deemed necessary.
1.21.3 Any deviations from approved drawings are subject to approval before work is commenced.
H. Definitions
1. General
Unless otherwise mentioned, the dimensions according to 2. and 3. are to be inserted [m] into the formulae stated in the
following Sections.
2. Principal dimensions
2.1 Length L
The length L is the distance in metres, on the summer load waterline from the foreside of stem to the after side of the rudder
post, or the centre of the rudder stock if there is no rudder post. L is not to be less than 96% and need not be greater than
97% of the extreme length of the summer load waterline. In ships with unusual stern and bow arrangement, the length L
will be specially considered.
2.2 Length Lc (according to ICLL, MARPOL 73/ 78, IBC - Code and IGC - Code )
The length Lc is to be taken as 96 % of the total length on a waterline at 85 % of the least moulded depth Hc measured from
the top of the keel, or as the length from the fore side of the stem to the axis of the rudder stock on that waterline, if that be
greater. In ships designed with a rake of keel the waterline on which this length is measured shall be parallel to the designed
waterline.
For the definition of the least moulded depth Hc see ICLL, Annex I, Chapter I, Regulation 3 (5).
2.3 Length L* (according to SOLAS 74 Chapter II-1, Reg 2)
The length L* of the ship is the length measured between perpendiculars taken at the extremities of the deepest subdivision
load line.
2.4 Subdivision length Ls
Reference is made to the definition in SOLAS 74, Chapter II–1, Reg. 25 – 2.2.1 and in Section 36, B.4.
2.5 Forward perpendicular FP.
The forward perpendicular coincides with the foreside of the stem on the waterline on which the respective length L, Lc,
or L* is measured.
2.6 Breadth B
The breadth B is the greatest moulded breadth of the ship.
2.7 Depth H
The depth H is the vertical distance, at the middle of the length L, from the base line3)
to top of the deck beam at side on
the uppermost continuous deck.
In way of effective superstructures the depth H is to be measured up to the superstructure deck for determining the ship's
scantlings.
2.8 Draught T
The draught T is the vertical distance at the middle of the length L from base line to freeboard marking for summer load
waterline. Fo r ships with timber load line the draught T is to be measured up to the freeboard mark for timber load
waterline.
3)
Base line is a line passing trough top of the keel plate at the middle of the length L.
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3. Frame spacing a
The frame spacing a will be measured from moulding edge to moulding edge of frame.
4. Block coefficient CB
Moulded block coefficient at load draught T, based on length L.
5. Ship's speed v0
Maximum service speed [kn], which the ship is designed to maintain at the summer load line draught and at the propeller
RPM corresponding to MCR (maximum continuous rating).
In case of controllable pitch propellers the speed v0 is to be determined on the basis of maximum pitch.
6. Definition of decks
6.1 Bulkhead deck
Bulkhead deck is the deck up to which the watertight bulkheads are carried.
6.2 Freeboard deck
Freeboard deck is the deck upon which the freeboard calculation is based.
6.3 Strength deck
Strength deck is the deck or the parts of a deck which form the upper flange of the effective longitudinal structure.
6.4 Weather deck
All free decks and parts of decks exposed to the sea are defined as weather deck.
6.5 Lower decks
Starting from the first deck below the uppermost continuous deck, the lower decks are defined as 2nd
, 3rd
deck, etc.
6.6 Superstructure decks
Thesuperstructuredeckssituatedimmediatelyabovetheuppermost continuous deck are termed forecastle deck, bridge deck,
and poop deck. Superstructure decks above the bridge deck are termed 2nd, 3rd superstructure deck, etc.
6.7 Positions of Hatchways, doorways and ventilators
For the arrangement of hatches, doors and ventilators the following areas are defined:
Pos. 1 S on exposed freeboard decks,
S on raised quarter decks,
S on the first exposed superstructure deck above the freeboard deck within the forward quarter of Lc.
Pos. 2 S on exposed superstructure decks aft of the forward quarter of Lc located at least one standard height of
superstructure above the freeboard deck
S on exposed superstructure decks within the forward quarter of Lc located at least two standard heights of
superstructure above the freeboard deck
J. International Conventions and Codes
Where reference is made of International Conventions and Codes these are defined as follows:
1. ICLL
International Convention on Load Lines, 1966 as amended.
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Section 2
Materials
A. General
All materials to be used for the structural members indicated in the Construction Rules are to be in accordance with the
Rules for Materials, Volume V. Materials the properties of which deviate from these Rule requirements may only be used
upon special approval.
B. Hull Structural Steel for Plates and Sections
1. Normal strength hull structural steel
1.1 Normal strength hull structural steel is a hull structural steel with a minimum nominal upper yield point ReH
of 235 N/mm2
and a tensile strength Rm of 400 - 520 N/mm2
, see also Section 17.A.3.
1.2 The material factor k in the formulae of the following Sections is to be taken 1,0 for normal strength hull
structural steel.
1.3 Normal strength hull structural steel is grouped into the grades KI-A, KI-B, KI-D, KI-E, which differ from each
other in their toughness properties. For the application of the individual grades for the hull structural members, see 3.
1.4 If for special structures the use of steels with yield properties less than 235 N/mm2
has been accepted, the material
factor k is to be determined by :
2. Higher strength hull structural steels
2.1 Higher strength hull structural steel is a hull structural steel, the yield and tensile properties of which exceed those
of normal strength hull structural steel. According to the Rules for Materials, Volume V, for three groups of higher strength
hull structural steels the nominal upper yield stress ReH has been fixed at 315, 355 and 390 N/mm2
respectively. Where
higher strength hull structural steel is used, for scantling purposes the values in Table 2.1 are to be used for the material
factor k mentioned in the various Sections.
For higher strength hull structural steel with other nominal yield stresses up to 390 N/mm2
, the material factor k may be
determined by the following formula:
Note
Especially when higher strength hull structural steels are used, limitation of permissible stresses due to buckling and fatigue
strength criteria may be required.
Table 2.1 Material factor k
ReH [N/mm2
] k
315
355
390
0,78
0,72
0,66
2.2 Higher strength hull structural steel is grouped into the following grades, which differ from each other in their
toughness properties :
KI-A 32/36/40
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Table 2.2 - Material classes and grades for ships in general
Structural member category Material class or grade
Secondary :
A1. Longitudinal bulkhead strakes, other than that belonging to the
Primary category
A2. Deck plating exposed to weather, other than that belonging to the
Primary or Special category
A3. Side plating
S Class I within 0,4 L amidships
S Grade A/AH outside 0,4 L amidships
Primary :
B1. Bottom plating, including keel plate
B2. Strength deck plating, excluding that belonging to the Special
category
B3. Continuous longitudinal plating of strength members above strength
deck, excluding hatch coamings
B4. Uppermost strake in longitudinal bulkhead
B5. Vertical strake (hatch side girder) and uppermost sloped strake in
top wing tank
S Class II within 0,4 L amidships
S Grade A/AH outside 0,4 L amidships
Special :
C1. Sheer strake at strength deck 1)
C2. Stringer plate in strength deck 1)
C3. Deck strake at longitudinal bulkhead excluding deck plating in way
of inner-skin bulkhead of double-hull ships 1)
S Class III within 0,4 L amidships
S Class II outside 0,4 L amidships
S Class I outside 0,6 L amidships
C4. Strength deck plating at outboard corners of cargo hatch openings in
container ships and other ships with similar hatch openings
configurations
S Class III within 0,4 L amidships
S Class II outside 0,4 L amidships
S Class I outside 0,6 L amidships
S Min. Class III within cargo region
C5. Strength deck plating at corners of cargo hatch openings in bulk
carriers, ore carriers, combination carriers and other ships with
similar hatch openings configurations
C5.1 Trunk deck and inner deck plating at corners of openings for liquid
and gas domes in membrane type liquefied gas carriers
S Class III within 0,6 L amidships
S Class II within rest of cargo region
C6. Bilge strake in ships with double bottom over the full breadth and
length less than 150 m 1)
S Class II within 0,6 L amidships
S Class I outside 0,6 L amidships
C7. Bilge strake in other ships 1)
S Class III within 0,4 L amidships
S Class II outside 0,4 L amidships
S Class I outside 0,6 L amidships
C8. Longitudinal hatch coamings of length greater than 0,15 L including
coaming top plate and flange
C9. End brackets and deck house transition of longitudinal cargo hatch
coamings
S Class III within 0,4 L amidships
S Class II outside 0,4 L amidships
S Class I outside 0,6 L amidships
S Not to be less than grade D/DH
1)
Single strakes required to be of class III within 0,4 L amidships are to have breadths not less than 800 + 5 L [mm] need not be grater than
1800 mm, unless limited by the geometry of the ship's design.
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Table 2.5 - Minimum material grades for ships with length exceeding 250 m
Structural member category Material grade
Shear strake at strength deck 1)
Grade E/EH within 0,4 L amidships
Stringer plate in strength deck 1)
Grade E/EH within 0,4 L amidships
Bilge strake 1)
Grade D/DH within 0,4 L amidships
1)
Single strakes required to be of Grade E/EH and within 0,4 L amidships are to have breadths not less than 800 + 5 L [mm], need not be grater
than 1800 mm, unless limited by the geometry of the ship's design.
Table 2.6 - Minimum material grades for single-side skin bulk carriers subjected to SOLAS regulation XII/6.5.3
Structural member category Material grade
Lower bracket of ordinary side frame 1), 2)
Grade D/DH
Side shell strakes included totally or partially between the two
points located to 0,125 R above and below the intersection of
side shell and bilge hopper sloping plate or inner bottom plate2)
Grade D/DH
1)
The term "lower bracket" means webs of lower brackets and webs of the lower part of side frames up to the point of 0,125 R above the
intersection of side shell and bilge hopper sloping plate or inner bottom plate.
2)
The span of the side frame R is defined as the distance between the supporting structures.
Table 2.7 - Minimum material grades for ships with ice strengthening
Structural member category Material grade
Shell strakes in way of ice strengthening area for plates Grade B/AH
Table 2.8 - Steel grades to be used, depending on plate thickness and material class
Thickness t [mm] 1)
> 15 > 20 > 25 > 30 > 35 > 40 > 50
Material class # 15 # 20 # 25 # 30 # 35 # 40 # 50 # 1003)
I A/AH A/AH A/AH A/AH B/AH B/AH D/DH D/DH2)
II A/AH A/AH B/AH D/DH D/DH 4)
D/DH 4)
E/EH E/EH
III A/AH B/AH D/DH D/DH 4)
E/EH E/EH E/EH E/EH
1)
Actual thickness of the structural member.
2)
For thicknesses t > 60 mm E/EH.
3)
For thicknesses t > 100 mm the steel grade is to be agreed with BKI.
4)
For nominal yield stresses ReH $ 390 N/mm2
EH.
3.2 Material selection for longitudinal structural members
Materials in the various strength members are not to be of lower grades than those corresponding to the material classes
and grades specified in Table 2.2 to Table 2.8. General requirements are given in Table 2.2, while additional minimum
requirements are given in the following:
Table 2.3: for ships, excluding liquefied gas carriers covered in Table 3, with length exceeding 150 m and single
strength deck,
Table 2.4: for membrane type liquefied gas carriers with length exceeding 150 m,
Table 2.5: for ships with length exceeding 250 m,
Table 2.6: for single side bulk carriers subjected to SOLAS regulation XII/6.5.3,
Table 2.7: for ships with ice strengthening.
The material grade requirements for hull members of each class depending on the thickness are defined in Table 2.8.
For strength members not mentioned in Tables 2.2 to 2.7, Grade A/AH may generally be used. The steel grade is to
correspond to the as-built plate thickness and material class.
Plating materials for sternframes supporting the rudder and propeller boss, rudders, rudder horns and shaft brackets are
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in general not to be of lower grades than corresponding to Class II.
3.3 Material selection for local structural members
3.3.1 The material selection for local structural members, which are not part of the longitudinal hull structure, may
in general be effected according to Table 2.9. For parts made of forged steel or cast steel C. is to be applied.
Table 2.9 - Material selection for local structural members
Structural member
Material
class
hawse pipe, stern tube, pipe stanchion3)
I
face plates and webs of girder systems, hatch cover II1)
rudder body 2)
, rudder horn, sole piece, stern frame, propeller brackets,
trunk pipe
II
1)
Class I material sufficient, where rolled sections are used or the parts are machine cut from plates
with condition on delivery of either "normalized", "rolled normalized" or "rolled thermo-
mechanical".
2)
See 3.3.2
3)
For pipe stanchions for cargo reefer holds Table 2.10 is applicable.
3.3.2 For rudder and rudder body plates subjected to stress concentrations (e.g. in way of lower support of semi-
spade rudders or at upper part of spade rudders) Class III is to be applied.
3.3.3 For top plates of machinery foundations located outside 0,6 L amidships, grade A ordinary hull structural
steel may also be used for thicknesses above 40 mm.
For members not specifically mentioned normally grade A/AH may be used. However, BKI may require also higher
grades depending on the stress level.
3.4 Material selection for structural members which are exposed to low temperatures
3.4.1 The material selection for structural members, which are continuously exposed to temperatures below 0 °C,
e.g. in or adjacent to refrigerated cargo holds, is governed by the design temperature of the structural members. The
design temperature is the temperature determined by means of a temperature distribution calculation taking into account
the design environmental temperatures. The design environmental temperatures for unrestricted service are:
air : + 5° C
sea water : 0° C.
3.4.2 For ships intended to operate permanently in areas with low air temperatures (below and including - 20 °C),
e.g. regular service during winter seasons to Arctic or Antarctic waters, the materials in exposed structures are to be
selected based on the design temperature tD , to be taken as defined in 3.4.5.
Materials in the various strength members above the lowest ballast waterline (BWL) exposed to air are not to be of
lower grades than those corresponding to classes I, II and III, as given in Table 2.10, depending on the categories of
structural members (Secondary, Primary and Special). For non-exposed structures and structures below the lowest
ballast waterline, see 3.2 and 3.3.
3.4.3 The material grade requirements of each material class depending on thickness and design temperature are
defined in Table 2.11. For design temperatures tD < - 55 °C, materials are to be specially considered.
3.4.4 Single strakes required to be of class III or of grade E/EH or FH are to have breadths not less 800 + 5 × L
[mm], maximum 1800 mm.
Plating materials for stern frames, rudder horns, rudders and shaft brackets are not to be of lower grades than those
corresponding to the material classes given in 3.3.
3.4.5 The design temperature tD is to be taken as the lowest mean daily average air temperature in the area of
operation, see Fig. 2.2. The following definitions apply:
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Mean : Statistical mean over an observation period of at least 20 years
Average : Average during one day and night.
Lowest : Lowest during the year.
For seasonally restricted service the lowest expected value within the period of operation applies.
4. Structural members which are stressed in direction of their thickness
In case of high local stresses in the thickness direction, e.g. due to shrinkage stresses in single bevel or double bevel
T-joints with a large volume of weld metal, steels with guaranteed material properties in the thickness direction
according to the Rules for Materials, Volume V, Section 4, I. are to be used.
Fig. 2.2 Commonly used definitions of temperatures
C. Forged Steel and Cast Steel
Forged steel and cast steel for stem, stern frame, rudder post as well as other structural components, which are subject of
this Rule, are to comply with the Rules for Materials, Volume V. The tensile strength of forged steel and of cast steel is
not to be less than 400 N/mm2
. Forged steel and cast steel are to be selected under consideration of B.3. In this respect
beside strength properties also toughness requirements and weldability shall be observed.
D. Aluminium Alloys
1. Where aluminium alloys, suitable for seawater, as specified in the Rules for Materials, Volume V, are used
for the construction of superstructures, deckhouses, hatchway covers and similar parts, the conversion from steel to
aluminium scantlings is to be carried out by using the material factor :
Rp0,2 = 0,2% proof stress of the aluminium alloy [N/mm2
]
Rm = tensile strength of the aluminium alloy [N/mm2
]
For welded connections the respective values in welded condition are to be taken. Where these figures are not available,
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Table 2.11 - Material grade requirements for classes I, II and III at low temperatures
Class I
Plate thickness
[mm]
tD tD tD tD
– 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C
normal
strength
higher
strength
normal
strength
higher
strength
normal
strength
higher
strength
normal
strength
higher
strength
t 10 A AH B AH D DH D DH
10 < t 15 B AH D DH D DH D DH
15 < t 20 B AH D DH D DH E EH
20 < t 25 D DH D DH D DH E EH
25 < t 30 D DH D DH E EH E EH
30 < t 35 D DH D DH E EH E EH
35 < t 45 D DH E EH E EH FH
45 < t 50 E EH E EH FH FH
Class II
Plate thickness
[mm]
tD tD tD tD
– 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C
normal
strength
higher
strength
normal
strength
higher
strength
normal
strength
higher
strength
normal
strength
higher
strength
t 10 B AH D DH D DH E EH
10 < t 20 D DH D DH E EH E EH
20 < t 30 D DH E EH E EH FH
30 < t 40 E EH E EH FH FH
40 < t 45 E EH FH FH
45 < t 50 E EH FH FH
Class III
Plate thickness
[mm]
tD tD tD tD
– 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C
normal
strength
higher
strength
normal
strength
higher
strength
normal
strength
higher
strength
normal
strength
higher
strength
t 10 D DH D DH E EH E EH
10 < t 20 D DH E EH E EH FH
20 < t 25 E EH E EH FH FH
25 < t 30 E EH E EH FH FH
30 < t 35 E EH FH FH
35 < t 40 E EH FH FH
40 < t 50 FH FH
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4. Fatigue strength
Where a fatigue strength analysis is required or will be carried out for structures or structural details this shall be in
accordance with the requirements of Section 20.
B. Upper and Lower Hull Flange
1. All continuous longitudinal structural members up to zo below the strength deck at side and up to zu above base
line are considered to be the upper and lower hull flange respectively.
2. Where the upper and/or the lower hull flange are made from normal strength hull structural steel their vertical
extent zo = zu equals 0,1 H.
On ships with continuous longitudinal structural members above the strength deck a fictitious depth H' = eB + e'D is to be
applied.
eB = distance between neutral axis of the midship section and base line [m]
e'D see Section 5, C.4.1
3. The vertical extent z of the upper and lower hull flange respectively made from higher tensile steel of one quality
is not to be less than:
z = e (1 S n @ k)
e = distance of deck at side or of the base line from the neutral axis of the midship section. For ships with
continuous longitudinal structural members above the strength deck, see Section 5, C.4.1
n =
W(a) = actual deck or bottom section modulus
W = rule deck or bottom section modulus.
Where two different steel grades are used it has to be observed that at no point the stresses are higher than the permissible
stresses according to Section 5, C.1.
C. Unsupported Span
1. Stiffeners, frames
The unsupported span R is the true length of the stiffeners between two supporting girders or else their length including end
attachments (brackets).
The frame spacings and spans are normally assumed to be measured in a vertical plane parallel to the centreline of the ship.
However, if the ship's side deviates more than 10° from this plane, the frame distances and spans shall be measured along
the side of the ship.
Instead of the true length of curved frames the length of the chord between the supporting points can be selected.
2. Corrugated bulkhead elements
The unsupported span R of corrugated bulkhead elements is their length between bottom or deck and their length between
vertical or horizontal girders. Where corrugated bulkhead elements are connected to box type elements of comparatively
low rigidity, their depth is to be included into the span R unless otherwise proved by calculations.
3. Transverses and girders
The unsupported span R of transverses and girders is to be determined according to Fig. 3.1, depending on the type of end
attachment.
In special cases, the rigidity of the adjoining girders is to be taken into account when determining the span of girder.
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Fig. 3.1 Unsupported span R
D. End Attachments
1. Definitions
For determining scantlings of beams, stiffeners and girders the terms "constraint" and "simple support" will be used.
"Constraint" will be assumed where for instance the stiffeners are rigidly connected to other members by means of brackets
or are running throughout over supporting girders.
"Simple support" will be assumed where for instance the stiffener ends are sniped or the stiffeners are connected to plating
only, see also 3.
2. Brackets
2.1 For the scantlings of brackets the required section modulus of the section is decisive. Where sections of different
section moduli are connected to each other, the scantlings of the brackets are generally governed by the smaller section.
2.2 The thickness of brackets is not to be less than :
t =
c = 1,2 for non-flanged brackets
= 0,95 for flanged brackets
k1 = material factor k for the section according to Section 2, B.2.
tK = corrosion addition according to K
W = section modulus of smaller section [cm3
]
tmin = 5 + tK mm
tmax = web thickness of smaller section.
For minimum thicknesses in tanks and in cargo holds of bulk carriers see Section 12, A.7., Section 23, B.5.3 and Section
24, A.13.
2.3 The arm length of brackets is not to be less than:
R = [mm]
Rmin = 100 mm
ct =
ta = "as built" thickness of bracket [mm]
> t according to 2.2
W = see 2.2
k2 = material factor k for the bracket according to Section 2, B.2.
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The arm length R is the length of the welded connection.
Note
For deviating arm length the thickness of brackets is to be estimated by direct calculations considering sufficient safety
against buckling.
2.4 The throat thickness a of the welded connection is to be determined according to Section 19, C.2.7.
2.5 Where flanged brackets are used the width of flange is to be determined according to the following formulae:
b = [mm]
b is not to be taken less than 50 mm and need not be taken greater than 90 mm.
3. Sniped ends of stiffeners
Stiffeners may be sniped at the ends, if the thickness of the plating supported by stiffeners is not less than:
t = [mm]
p = design load [kN/m2
]
R = unsupported length of stiffener [m]
a = spacing of stiffeners [m]
ReH = minimum nominal upper yield point of the plating material [N/mm2
] according to Section 2, B.2
c = 15,8 for watertight bulkheads and for tank bulkheads when loaded by p2 according to Section 4, D.1.2
= 19,6 otherwise,
4. Corrugated bulkhead elements
Care is to be taken that the forces acting at the supports of corrugated bulkheads are properly transmitted into the adjacent
structure by fitting structural elements such as carlings, girders or floors in line with the corrugations.
Note
Where carlings or similar elements cannot be fitted in line with the web strips of corrugated bulkhead elements, these web
strips cannot be included into the section modulus at the support point for transmitting the moment of constraint.
Deviating from the formula stipulated in Section 11, B.4.3 the section modulus of a corrugated element is then to be
determined by the following formulae:
W = [cm3
]
E. Effective Breadth of Plating
1. Frames and stiffeners
Generally, the spacing of frames and stiffeners may be taken as effective breadth of plating.
2. Girders
2.1 The effective breadth of plating “em” of frames and girders may be determined according to Table 3.1 considering
the type of loading.
Special calculations may be required for determining the effective breadth of one-sided or non-symmetrical flanges.
2.2 The effective cross sectional area of plates is not to be less than the cross sectional area of the face plate.
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Table 3.1 Effective breadth em of frames and girders
R/e 0 1 2 3 4 5 6 7 8
em1/e 0 0,36 0,64 0,82 0,91 0,96 0,98 1,00 1,00
em2/e 0 0,20 0,37 0,52 0,65 0,75 0,84 0,89 0,90
em1 is to be applied where girders are loaded by uniformly distributed loads or else by not
less than 6 equally spaced single loads.
em2 is to be applied where girders are loaded by 3 or less single loads.
Intermediate values may be obtained by direct interpolation.
R = length between zero-points of bending moment curve, i.e. unsupported span in case of
simply supported girders and 0,6 x unsupported span in case of constraint of both ends
of girder
e = width of plating supported, measured from centre to centre of the adjacent unsupported
fields.
2.3 Where the angle " between web of stiffeners or else of girders and the attached plating is less than 75E the
required section modulus is to be multiplied by the factor 1/sin ".
2.4 The effective width of stiffeners and girders subjected to compressive stresses may be determined according to
F.2.2, but is in no case to be taken greater than the effective breadth determined by 2.1.
3. Cantilevers
Where cantilevers are fitted at every frame, the effective width of plating may be taken as the frame spacing.
Where cantilevers are fitted at a greater spacing the effective breadth of plating at the respective cross section may
approximately be taken as the distance of the cross section from the point on which the load is acting, however, not greater
than the spacing of the cantilevers.
F. Proof of Buckling Strength
The calculation method is based on DIN-standard 18800
1. Definitions
a = length of single or partial plate field [mm]
b = breadth of single plate field [mm]
" = aspect ratio of single plate field
=
n = number of single plate field breadths within the partial or total plate field
longitudinal : stiffiner in the direction of the length a
transverse : stiffiner in the direction of the length b
Fig. 3.2 Definition of plate fields subject to buckling
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![F Section 3 - Design Pinciples3-6/24
t = nominal plate thickness [mm]
= ta – tK [mm]
ta = plate thickness as built [mm]
tK = corrosion addition according to K. [mm]
Fx = membrane stress in x-direction [N/mm2
]
Fy = membrane stress in y-direction [N/mm2
]
J = shear stress in the x-y plane [N/mm2
]
Compressive and shear stresses are to be taken positive, tension stresses are to be taken negative.
Note
If the stresses in the x- and y- direction contain already the Poisson - effect, the following modified stress values may be
used:
Both stresses Fx* and Fy* are to be compressive stresses,
in order to apply the stress reduction according to the following formulae:
Fx=
Fy=
, = stresses containing the Poisson-effect
Where compressive stress fulfils the condition Fy* < 0,3 @ Fx*, then Fy = 0 and Fx = Fx*.
Where compressive stress fulfils the condition Fx* < 0,3 @ Fy*, then Fx = 0 and Fy = Fy*.
When at least Fx* or Fy* is tensio n stress, then Fx = Fx* and Fy = Fy*.
R = edge stress ratio according to Table 3.3
F1 = correction factor for boundary condition at the long. stiffeners according to Table 3.2
Fe = reference stress
= [N/mm2
]
E = Young's modulus
= [N/mm2
] for steel
= [N/mm2
] for aluminium alloys
Table 3.2 - Correction Factor F1
1,0 for stiffeners sniped at both ends
Guidance values where both ends are effectively connected to adjacent structures * :
1,05 for flat bars
1,10 for bulb sections
1,20 for angle and tee-sections
1,30 for girders of high rigidity
(e.g. bottom transverses)
* Exact values may be determined by direct calculations.
ReH = nominal yield point [N/mm2
] for hull structural steels according to Section 2, B.2.
= 0,2 % proof stress [N/mm2
] for aluminium alloys
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![F Section 3 - Design Pinciples3-10/24
Table 3.4 - Curved plate field R/t 25001)
Load case
Aspect ratio
b / R
Buckling factor K Reduction factor 6
pe = external pressure
[N/mm2
]
K =
6x = 12)
for 8 # 0,4
6x =
for 0,4 < 8 #1,2
6x = for 8 > 1,2
K =
K =
6y = 1 2)
for 8 # 0,25
6y =
for 0,25 < 8 # 1
6y = 0.3 / 83
for 1 < 8 # 1,5
6y = 0.2 / 82
for 8 > 1,5
K =
K =
as in load case 1a
K =
K = 6J = 1
for 8 # 0,4
6J =
for 0,4 < 8 # 1,2
6J =
for 8 > 1,2
KJ =
KJ =
Explanations for boundary conditions : plate edge free
plate edge simply supported
plate edge clamped
1)
For curved plate fields with a very large radius the 6-value need not to be taken less than derived for the expanded plane field.
2)
For curved single fields. e.g. the bilge strake, which are located within plane partial or total fields, the reduction factor 6 may be taken as follows:
Load case 1b : 6x = 0,8/82
1,0 ; load case 2: 6y = 0,65/82
1,0
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![F Section 3 - Design Pinciples3-12/24
Stress distribution between two girders :
c1 = 0 # c1 # 1
c2 =
Fx1, Fx2 = normal stresses in flange plates of adjacent girder 1 and 2 with spacing e.
= proportionate effective width of and respectively of girder 1 within the distance e
=
= proportionate effective width of and respectively of girder 2 within the distance e
=
y = distance of considered location from girder 1
Scantlings of plates and stiffeners are in general to be determined according to the maximum stresses Fx(y) at girder webs
and stiffeners respectively. For stiffeners under compression arranged parallel to the girder web with spacing b no lesser
value than 0,25 @ ReH shall be inserted for Fx(y=b).
Shear stress distribution in the flange plates may be assumed linearly.
2.3 Webs and flanges
For non-stiffened webs and flanges of sections and girders proof of sufficient buckling strength as for single plate fields is
to be provided according to 2.1.
Note
Within 0,6 L amidships the following guidance values are recommended for the ratio web depth to web thickness and/or
flange breadth to flange thickness:
flat bars:
angle-, tee and bulb sections:
web:
flange:
bi = b1 or b2 according to Fig. 3.3, the larger value is to be taken.
3. Proof of partial and total fields
3.1 Longitudinal and transverse stiffeners
Proof is to be provided that the continuous longitudinal and transverse stiffeners of partial and total plate fields comply with
the conditions set out in 3.2 and 3.3.
3.2 Lateral buckling
Fa = uniformly distributed compressive stress in the direction of the stiffener axis [N/mm2
]
= Fx for longitudinal stiffeners
= Fy for transverse stiffeners
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![Section 3 - Design Pinciples F 3-13/24
Fb = bending stress in the stiffeners
= [N/mm2
]
M0 = bending moment due to deformation w of stiffener
= [N @ mm]
M1 = bending moment due to the lateral load p for continuous longitudinal stiffeners :
= [N @ mm]
for transverse stiffeners :
= [N @ mm]
p = lateral load [kN/m²] according to Section 4
FKi = ideal buckling force of the stiffener [N]
FKix = for long. stiffeners
FKiy = for transv. stiffeners
Ix, Iy = moments of inertia of the longitudinal or transverse stiffener including effective width of plating according
to 2.2 [cm4
]
Ix $
Iy $
pz = nominal lateral load of the stiffener due to Fx, Fy and J [N/mm2
]
for longitudinal stiffeners:
pzx =
for transverse stiffeners:
pzy =
Fx1 = [N/mm2
]
cx, cy= factor taking into account the stresses vertical to the stiffener's axis and distributed variable along the
stiffener's length
= 0,5 (1 + R) for 0 # R # 1
= for R < 0
R = edge stress ratio according to Table 3.3
Ax,Ay = sectional area of the longitudinal or transverse stiffener respectively [mm2
]
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![F Section 3 - Design Pinciples3-14/24
J1 =
for longitudinal stiffeners:
: m1 = 1,47 m2 = 0,49
: m1 = 1,96 m2 = 0,37
for transverse stiffeners:
: m1 = 0,37 m2 =
: m1 = 0,49 m2 =
w = wo + w1
wo = assumed imperfection [mm],
for long. stiffeners
for transv. stiffeners
however wo mm
Note
For stiffeners sniped at both ends wo shall not be taken less than the distance from the midpoint of plating to the neutral
axis of the profile including effective width of plating.
w1 = deformation of stiffener due to lateral load p at midpoint of stiffener span [mm]
In case of uniformly distributed load the following values for w1 may be used :
for longitudinal stiffeners:
w1 =
for transverse stiffeners:
w1 =
cf = elastic support provided by the stiffener [N/mm2
]
cfx = for long. stiffeners
cpx =
cx" = for a $ 2 b
= for a < 2 b
cfy = for transv. stiffeners
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-62-320.jpg)
![Section 3 - Design Pinciples F 3-15/24
cpy =
cy" = for n @ b $ 2 a
= for n @ b < 2 a
cs = factor accounting for the boundary conditions of the transverse stiffener
= 1,0 for simply supported stiffeners
= 2,0 for partially constraint stiffeners
Wst = section modulus of stiffener (long. or transverse) [cm3
] including effective width of plating according to
2.2.
If no lateral load p is acting the bending stress Fb is to be calculated at the midpoint of the stiffener span for the fibre which
results in the largest stress value. If a lateral load p is acting, the stress calculation is to be carried out for both fibres of the
stiffener’s cross sectional area (if necessary for the biaxial stress field at the plating side).
Note
Longitudinal and transverse stiffeners not subjected to lateral load p have sufficient scantlings if their moments of inertia
Ix and Iy are not less than obtained by the following formulae :
Ix = [cm4
]
Iy = [cm4
]
3.3 Torsional buckling
3.3.1 Longitudinal stiffeners :
6T = 1,0 for
= for
k =
8T = reference degree of slenderness
8T =
FKiT = [N/mm2
]
For IP, IT, IT see Fig.3.3 and Table 3.5.
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![F Section 3 - Design Pinciples3-16/24
Fig. 3.3 - Main dimensions of typical longitudinal stiffners
IP = polar moment of inertia of the stiffener related to the point C [cm4
]
IT = St. Vernant’s moment of inertia of the stiffener [cm4
]
IT = sectorial moment of inertia of the stiffener related to the point C [cm6
]
g = degree of fixation
=
hw = web height [mm]
tw = web thickness [mm]
bf = flange breadth [mm]
tf = flange thickness [mm]
Aw = web area hw × tw
Af = flange area bf × tf .
3.3.3 Transverse stiffeners
For transverse stiffeners loaded by compressive stresses and which are not supported by longitudinal stiffeners, proof is to
be provided in accordance with 3.3.1 analogously.
Table 3.5 Formulas for the calculation of moments of inertia IP, IT, and IT
Profile IP IT IT
flat bar
profile with
bulb or
flange
+
for bulb and angle profiles:
for T - profiles:
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![Section 3 - Design Pinciples G, H 3-17/24
G. Rigidity of Transverses and Girders
The moment of inertia of deck transverses and girders, is not to be less than :
I = c @ W @ R [cm4
]
c = 4,0 if both ends are simply supported
= 2,0 if one end is constrained
= 1,5 if both ends are constrained
W = section modulus of the structural member considered [cm3
]
R = unsupported span of the structural member considered [m]
H. Structural Details
1. Longitudinal members
1.1 All longitudinal members taken into account for calculating the midship section modulus are to extend over the
required length amidships and are to be tapered gradually to the required end scantlings (see also Section 5, C.1).
1.2 Abrupt discontinuities of strength of longitudinal members are to be avoided as far as practicable. Where
longitudinal members having different scantlings are connected with each other, smooth transitions are to be provided.
Special attention in this respect is to be paid to the construction of continuous longitudinal hatch coamings forming part of
the longitudinal hull structure.
1.3 At the ends of longitudinal bulkheads or continuous longitudinal walls suitable scarphing brackets are to be
provided.
2. Transverses and girders
2.1 Where transverses and girders fitted in the same plane are connected to each other, major discontinuities of
strength shall be avoided. The web depth of the smaller girder shall, in general, not be less than 60% of the web depth of
the greater one.
2.2 The taper between face plates with different dimensions is to be gradual. In general the taper shall not exceed
1: 3. At intersections the forces acting in the face plates are to be properly transmitted.
2.3 For transmitting the acting forces the face plates are to be supported at their knuckles. For supporting the face
plates of cantilevers, see Fig. 3.4.
Fig. 3.4 - Support of face plates of cantilevers
2.4 Upon special approval the stiffeners at the knuckles may be omitted if the following condition is complied with:
Fa = actual stress in the face plate at the knuckle [N/mm2
]
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![H Section 3 - Design Pinciples3-18/24
Fp = permissible stress in the face plate [N/mm2
]
bf = breadth of face plate [mm]
be = effective breadth of face plate :
be =
tw = web thickness [mm]
tf = face plate thickness [mm]
b = [mm]
c =
cmax = 1
2" = knuckle angle [E], see Fig. 3.5
"max = 45E
R = radius of rounded face plates [mm]
= tf for knuckled face plates
n1 = 1 for un-symmetrical face plates (face plate at one side only)
= 2 for symmetrical face plates
n2 = 0 for face plate not supported by brackets
= # 1,0
for face plates of multi-web girders
n3 = 3 if no radial stiffener is fitted
= 3000 if two or more radial stiffeners are fitted or if one knuckle stiffener is fitted according to Fig. 3.5
(a).
n3 = if one stiffener is fitted according to Fig. 3.5 (b).
3 # n3 # 3000
d = distance of the stiffener from the knuckle [mm]
For proof of fatigue strength of the weld seam in the knuckle, the stress concentration factor KS (angle 2 " according to
Fig. 3.5 < 35°) related to the stress Fa in the face plate of thickness tf may be estimated as follows and may be evaluated with
case 5 of Table 20.3 :
KS =
n4 = 7,143 for > 8
= for 8 $ > 1,35
= 0,5 @ + 0,125 for 1,35 $ $ ! 0,25
The welding seam has to be shaped according to Fig. 3.6.
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![J, K Section 3 - Design Pinciples3-22/24
Fig. 3.10 Parameters m and c to determine the notch factors of rectangular openings loaded by superimposed
longitudinal and shear stresses
Note
Because the notch factor and the equivalent stress are always positive, the sign of F1 governs the most unfavourable
superposition of the stress components in any of the four corners. A load consisting of shear only, results in notch stresses
of equal size with two positive and two negative values in the opposite corners.
An exact evaluation of notch stresses is possible by means of finite element calculations. For fatigue investigations the stress
increase due to geometry of cut-outs has to be considered, see Table 20.3.
Note
These notch factors can only be used for girders with multiple openings if there is no correlation between the different
openings regarding deformations and stresses.
K. Corrosion Additions
1. The scantling requirements of the subsequent Sections imply the following general corrosion addition tK :
tK = 1,5 mm for t’ 10 mm
= mm, max. 3,0 mm for t’ > 10 mm
t’ = required rule thickness excluding tK [mm].
k = material factor according to Section 2, B.2.
2. For structural elements in specified areas tK is not to be less than given in Table 3.6. For corrosion protection see
Section 38.
Table 3.6 - Minimum corrosion addition
Area
tKmin
[mm]
In ballast tanks where the weather deck forms the tank
top, 1,5 m below tank top1)
.
2,5
In cargo oil tanks where the weather deck forms the tank
top, 1,5 m below tank top.
Horizontal members in cargo oil and fuel oil tanks.
2,0
Deck plating below elastically mounted deckhouses 3,0
Longitudinal bulkheads of ships assignedtothe Notation
G and exposed to grab operation
2,5
1)
tK = 2,5 mm for all structures within topside tanks of bulk carriers.
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![Section 3 - Design Pinciples K, L 3-23/24
3. For structures in dry spaces such as box girders of container ships and for similar spaces the corrosion addition
is:
tK = , max. 2,5 mm
however, not less than 1,0 mm.
4. Corrosion addition for hatch covers and hatch coamings are to be determined according to Section 17.
L. Additional Stresses in Asymmetric Sections
1. Additional stresses for fatique strength analysis
The additional stress Fh occurring in non-symmetric sections may be calculated by the following formulae :
Q = load on section parallel to its web within the unsupported span Rf [kN]
= p @ a @ Rf [kN] in case of uniformly distributed load p [kN/m2
]
Rf = unsupported span of flange [m]
tf, bl, b2 = flange dimensions [mm] as shown Fig. 3.11.
b1 b2
Wy = Section modulus of section related to the y-y axis including the effective width of plating [cm3
]
Wz = section modulus of the partial section consisting of flange and half of web area related to the
z-z axis [cm3
] (Bulb sections may be converted into a similar L-section)
Fig. 3.11 - Asymmetrical profile
c = factor depending on kind of load, stiffness of the section’s web and length and kind of support
of the profile.
For profiles clamped at both ends and constant area load c = 80 can be taken for approximation.
A precise calculation may be required, e.g. for longitudinal frames of tankers.
This additional stress Fh is to be added directly to other stresses such as those resulting from local and hull girder bending.
2. Correction of section modulus
The required section modulus Wy according to A.2. is to be multiplied with the factor ksp according to Table 3.7
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![Section 4 - Design Loads A 4-1/10
Section 4
Design Loads
A. General, Definitions
1. General.
This Section provides data regarding design loads for determining the scantlings of the hull structural elements by means
of the design formulae given in the following Sections or by means of direct calculations. The dynamic portions of the
design loads are design values which can only be applied within the design concept of this Volume.
2. Definitions
2.1 Load centre
2.1.1For plates:
– Vertical stiffening system:
0,5 @ stiffener spacing above the lower support of plate field, or lower edge of plate when the thickness changes
within the plate field.
– Horizontal stiffening system:
Midpoint of plate field.
2.1.2For stiffeners and girders:
Centre of span R.
2.2 Definition of symbols
v0 = ship's speed according to Section 1, H.5.
Dc = density of cargo as stowed [t/m3
]
D = density of liquids [t/m3
]
= 1,0 t/m3
for fresh water and sea water
z = vertical distance of the structure's load centre above base line [m]
x = distance from aft end of length L [m]
p0 = basic external dynamic load
= 2,1 @ (CB + 0,7) @ c0 @ cL @ f [kN/m2
]
for wave directions with or against the ship’s heading
p01 = 2,6 @ (CB + 0,7) @ c0 @ cL [kN/m2
]
for wave directions transverse the ship’s heading
CB = moulded block coefficient according to Section 1, H.4., where CB is not to be taken less than 0,60.
c0 = wave coefficient
= for L < 90 m
= for 90 < L < 300 m
= 10,75 @ cRW for L > 300 m
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![A, B Section 4 - Design Loads4-2/10
cL = length coefficient
= for L < 90 m
= 1,0 for L 90 m
cRW = service range coefficient
= 1,00 for unlimited service range
= 0,90 for service range P
= 0,75 for service range L
= 0,60 for service range T
f = probability factor
= 1,0 for plate panels of the outer hull (shell plating, weather decks)
= 0,75 for secondary stiffening members of the outer hull (frames, deck beams), but not less than fQ according
to Section 5, D.1.
= 0,60 for girders and girder systems of the outer hull (web frames, stringers, grillage systems), but not less
than fQ/1,25
cD, cF = distribution factors according to Table 4.1.
B. External Sea Loads
1. Load on weather decks
1.1 The load on weather deck is to be determined according to the following formula:
pD = p0 [kN/m2
]
Table 4.1 Distribution factors for sea loads on ship's sides and weather decks
Range Factor cD Factor cF
1)
A 0 < 0,2 1,2 n 1,0 +
M 0,2 < 0,7 1,0 1,0
F 0,7 1,0
1,0 +
c = 0,15 L n 10
where: Lmin = 100 m
Lmax = 250 m
1,0 +
1)
Within the range A the ratio x/L need not be taken less than 0,1, within the range F the ratio x/L need not be taken greater than
0,93
Fig. 4.1 Longitudinal sections A, M, and F according to Table 4.1
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![Section 4 - Design Loads B 4-3/10
1.2 For strength decks which are to be treated as weather decks as well as for forecastle decks the load is not to be
less than the greater of the following two values :
pDmin = 16 @ f [kN/m2
]
and
pDmin = 0,7 @ p0 [kN/m2
]
1.3 Where deck cargo is intended to be carried on the weather deck resulting in load greater than the value determined
according to 1.1, the scantlings are governed by the greater load (see also C).
Where the stowage height of deck cargo is less than 1,0 m, the deck cargo load may require to be increased by the following
value :
pz = 10 (1 S hc) [kN/m2
]
hc = stowage height of the cargo [m]
2. Load on ship's sides and of bow and stern structures
2.1 Load on ship's sides
The external load ps on the ship's sides is to be determined according to 2.1.1 and 2.1.2.
2.1.1For elements the load centre of which is located below load waterline:
ps = [kN/m2
]
for wave directions with or against the ship's heading.
ps1 = [kN/m2
]
for wave directions transverse to the ship's heading including quasi-static pressure increase due to heel.
y = horizontal distance between load centre and centreline [m]
2.1.2For elements the load centre of which is located above the load waterline:
ps = [kN/m2
]
for wave directions with or against the ship's heading.
ps1 = [kN/m2
]
for wave directions transverse to the ship's heading including quasi-static pressure increase due to heel.
2.2 Load on bow structures
The design load for bow structures from forward to 0,1 L behind F.P. and above the ballast waterline in accordance with
the draft Tb in 4. is to be determined according to the following formulae :
pe = [kN'm2
]
with Lmax = 300m.
c = 0,8 in general
=
for extremely flared sides where the flare angle " is larger than 40°.
The flare angle " at the load centre is to be measured in the plane of frame between a vertical line and the tangent to the side
shell plating.
For unusual bow shapes pe can be specially considered.
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![B Section 4 - Design Loads4-4/10
pe shall not be smaller than ps according to 2.1.1 or 2.1.2 respectively.
Aft of 0,1 L from F.P. up to 0,15 L from F.P. the pressure between pe and ps is to be graded steadily.
The design load for bow doors is given in Section 6, H.3.
2.3 Load on stern structures
The design load for stern structures from the aft end to 0,1 L forward of the aft end of L and above the smallest design
ballast draught at the centre of the rudder stock up to T + c0/2 is to be determined according to the following formulae:
pe = cA @ L [kN/m2
]
with Lmax = 300m.
cA = 0,3 @ c $ 0,36
c = see 2.2
pe = shall not be smaller than ps according to 2.1.1 or 2.1.2 respectively
3. Load on the ship's bottom
The external load pB of the ship's bottom is to be determined according to the greater of the following formulae:
pB = 10 @ T + p0 @ cF [kN/m2
]
For wave direction with or against the ship’s heading.
pB1 = [kN/m2
]
For wave direction transverse to the ship’s heading including quasi-static pressure increase due to heel.
4. Design bottom slamming pressure
The design bottom slamming pressure in the fore body may be determined by the following formulae:
pSL = [kN/m2
] for L 150 m
= [kN/m2
] for L > 150 m
c1 = 0 # c1 # 1,0
Tb = smallest designballast draught at F.P for normal ballast conditions [m],according to which the strengthening
of bottom forward, see Section.6, E. has to be done.
This value has to be recorded in the Class Certificate and in the loading manual.
Where the sequential method for ballast water exchange is intended to be applied, Tb is to be considered for the sequence
of exchange.
Note
With respect to the observation of the smallest design ballast draught Tb , an exception is possible, if during the exchange
of ballast water weather conditions are observed the parameters of which are put down in the annex to the Certificate of
Class.
cSL = distribution factor, see also Fig. 4.2
cSL = 0 for 0,5
= for 0,5 < < 0,5 + c2
= 1,0 for 0,5 + c2 < < 0,65 + c2
BKI - Rules for Hull -2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-76-320.jpg)
![Section 4 - Design Loads B 4-5/10
= for > 0,65 + c2
c2 = 0,33 @ CB +
c2max = 0,35
cA = 10/A
= 1,0 for plate panels and stiffeners.
A = loaded area between the supports of the structure considered [m2
]
0,3 < cA 1,0
cs =
cRW = see A.2.2
Fig. 4.2 Distribution factor cSL
5. Load on decks of superstructures and deckhouses
5.1 The load on exposed decks and parts of superstructure and deckhouse decks, which are not to be treated as
strength deck, is to be determined as follows:
pDA = pD @ n [kN/m2
]
pD = load according 1.1
n =
= 1,0 for the forecastle deck
nmin = 0,5
For deckhouses the value so determined may be multiplied by the factor
b’ = breadth of deckhouse
B’ = largest breadth of ship at the position considered.
Except for the forecastle deck the minimum load is:
pDAmin = 4 [kN/m2
]
5.2 For exposed wheel house tops the load is not to be taken less than
p = 2,5 [kN/m2
]
BKI - Rules for Hull -2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-77-320.jpg)
![C Section 4 - Design Loads4-6/10
C. Cargo Loads, Load on Accommodation Decks
1. Load on cargo decks
1.1 The load on cargo decks is to be determined according to the following formulae:
pL = pc (1 + av) [kN/m2
]
pc = static cargo load [kN/m2
]
if no cargo load is given: pc = 7 @ h for 'tween decks but not less than 15 kN/m2
.
h = mean 'tween deck height [m].
In way of hatch casings the increased height of cargo is to be taken into account.
av = acceleration factor as follows:
= F @ m
F = 0,11
m = mo - 5 (mo - 1) for 0 < < 0,2
= 1,0 for 0,2 < < 0,7
= for 0,7 < < 1,0
mo = (1,5 + F)
v0 = see A.2.2. v0 is not to be taken less than [kn]
1.2 For timber and coke deck cargo the load on deck is to be determined by the following formulae:
pL = 5 @ hs (1 + av) [kN/m2
]
hs = stowing height of cargo [m].
1.3 The loads due to single forces PE (e.g. in case of containers) are to be determined as follows:
P = PE (1 + av) [kN].
1.4 The cargo pressure of bulk cargoes is to be determined by the following formulae:
pbc = pc (1 + av) [kN/m2
]
pc = static bulk cargo load
= 9,81 A Dc A h A n [kN/m2
]
h = distance between upper edge of cargo and the load centre [m]
n =
" = angle [E] between the structural element considered and a horizontal plane
( = angle of repose of the cargo [E]
2. Load on inner bottom
2.1 The inner bottom cargo load is to be determined as follows:
pi = 9,81 @ @ h (1 + av) [kN/m2
]
G = mass of cargo in the hold [t]
V = volume of the hold [m3
] (hatchways excluded)
h = height of the highest point of the cargo above the inner bottom [m], assuming hold to be completely filled.
BKI - Rules for Hull -2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-78-320.jpg)
![Section 4 - Design Loads C, D 4-7/10
av = see 1.1
For calculating av the distance between the centre of gravity of the hold and the aft end of the length L is
to be taken.
2.2 For inner bottom load in case of ore stowed in conical shape, see Section 23, B.3.
3. Loads on accommodation and machinery decks
3.1 The deck load in accommodation and service spaces is:
p = 3,5 ( 1 + av ) [kN/m2
]
3.2 The deck load of machinery decks is:
p = 8 ( 1 + av ) [kN/m2
]
3.3 Significant single forces are also to be considered, if necessary.
D. Load on Tank Structures
1. Design pressure for filled tanks
1.1 The design pressure for service conditions is the greater of the following values:
p1 = 9,81@ h1 @ D (1 + av) + 100 @ pv [kN/m2
]
or
p1 = [kN/m2
]
h1 = distance of load centre from tank top [m]
av = see C.1.1
n = design heeling angle [E] for tanks
= arctan in general
fbk = 0,5 for ships with bilge keel
= 0,6 for ships without bilge keel
n > 20o
for hatch covers of holds carrying liquids
b = upper breadth of tank [m]
y = distance of load centre from the vertical longitudinal central plane of tank [m]
pv = set pressure of pressure relief valve [bar], if a pressure relief valve is fitted
= working pressure during ballast water exchange [bar]
=
)z = distance from top of overflow to tank top [m]
)pv = pressure losses in the overflow line [bar]
)pvmin = 0,1 bar
pvmin = 0,1 bar during ballast water exchange for both, the sequential method as well as the flow-through method
= 0,2 bar (2,0 mWS) for cargo tanks of tankers (see also Rules for Machinery Installations, Volume
III, Section 15).
Smaller set pressures than 0,2 bar may be accepted in special cases. The actual set pressure will be entered into the Class
Certificate.
BKI - Rules for Hull -2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-79-320.jpg)
![D, E Section 4 - Design Loads4-8/10
1.2 The maximum static design pressure is:
p2 = 9,81 @ h2 [kN/m2
]
h2 = distance of load centre from top of overflow or from a point 2,5 m above tank top, whichever is the greater.
Tank venting pipes of cargo tanks of tankers are not to be regarded as overflow pipes.
For tanks equipped with pressure relief valves and/or for tanks intended to carry liquids of a density greater than 1 t/m3
,
the head h2 is at least to be measured to a level at the following distance hp above tank top:
hp = 2,5 @ D [mWS], head of water [m],
or
= 10 @ pv [mWS], where pv > 0,25 @ D
Regarding the design pressure of fuel tanks and ballast tanks which are connected to an overflow system, the dynamic
pressure increase due to the overflowing is to be taken into account in addition to the static pressure height up to the highest
point of the overflow system, see also Regulation for Construction, Equipment and Testing of Closed Fuel Overflow
Systems.
2. Design pressure for partially filled tanks
2.1 For tanks which may be partially filled between 20% and 90% of their height, the design pressure is not to be
taken less than given by the following formulae:
2.1.1For structures located within 0,25 Rt from the bulkheads limiting the free liquid surface in the ship's longitudinal
direction:
pd = [kN/m2
]
Rt = distance [m] between transverse bulkheads or effective transverse wash bulkheads at the height where the
structure is located.
2.1.2For structures located within 0,25 bt from the bulkheads limiting the free liquid surface in the ship's transverse
direction:
pd = [kN/m2
]
bt = distance [m] between tank sides or effective longitudinal wash bulkhead at the height where the structure
is located.
nx =
ny =
x1 = distance of structural element from the tank’s end in the ship’s longitudinal direction [m]
y1 = distance of structural element from the tank’s sides in the ship’s transverse direction [m]
2.2 For tanks with ratios Rt/L > 0,1 or bt/B > 0,6 a direct calculation of the pressure pd may be required.
E. Design Values of Acceleration Components
1. Acceleration components
The following formulae may be taken for guidance when calculating the acceleration components owing to ship's motions.
Vertical acceleration:
az =
BKI - Rules for Hull -2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-80-320.jpg)
![Section 4 - Design Loads E 4-9/10
Transverse acceleration:
ay =
Longitudinal acceleration:
ax =
where
A =
The acceleration components take account of the following components of motion:
Vertical acceleration (vertical to the base line) due to heave, and pitch.
Transverse acceleration (vertical to the ship's side) due to sway, yaw , and roll including gravity component of roll.
Longitudinal acceleration (in longitudinal direction) due to surge and pitch including gravity component of pitch.
ax, ay and az are maximum dimensionless accelerations (i.e., relative to the acceleration gravity g) in the related direction
x, y and z. For calculation purposes they are considered to act separately.
a0 =
L0 = length of ship L [m], but for determination of a0 the length L0 shall not be taken less than 100 m
k =
= metacentric height [m]
kmin = 1,0
fQ = probability factor depending on probability level Q as outline in Table 4.2.
Table 4.2 Probability factor fQ for a straightline spectrum of seaway-induced stress ranges
Q fQ
10-8
10-7
10-6
10-5
10-4
1,000
0,875
0,750
0,625
0,500
2. Combined acceleration
The combined acceleration a$ may be determined by means of the "acceleration ellipse" according to Fig. 4.3 (e.g. y-z-
plane).
BKI - Rules for Hull -2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-81-320.jpg)
![A, B Section 5 - Longitudinal Strength5-6/27
x = distance [m] between aft end of length L and the position considered
v0 = speed of the ship [kn] according to Section.1, H.5.
Iy = moment of inertia of the midship section [m4
] around the horizontal axis at the position x/L
eB = distance [m] between neutral axis of hull section and base line
eD = distance [m] between neutral axis of hull section and deck line at side
ez = vertical distance of the structural element considered from the horizontal neutral axis [m] (positive sign for
above the neutral axis, negative sign for below)
WB = section modulus of section [m3
] related to base line
WD = section modulus of section [m3
] related to deck line at side
S = first moment of the sectional area considered [m3
] related to the neutral axis
MT = total bending moment in the seaway [kNm]
= MSW + MWV
MSW = permissible vertical still water bending moment [kNm] (positive sign for hogging, negative sign for sagging
condition)
MWV= verticalwavebendingmoment[kNm](positivesignforhogging,MWVhog,negativesignforsaggingcondition,
MWVsag)
MWH= horizontal wave bending moment [kNm] (positive signfor tension starboard side, negative for compression
in starboard side)
MST = static torsional moment [kNm]
MWT = wave induced torsional moment [kNm]
QT = total vertical shear force in the seaway [kN]
= QSW + QWV
QSW = permissible vertical still water shear force [kN]
QWV = vertical wave shear force [kN]
QWH = horizontal wave shear force [kN].
Sign rule see Fig. 5.1
Fig. 5.1 Sign rule
B. Loads on the Ship’s Hull
1. General
In general the global loads on the hull in a seaway can be calculated with the formulae stated below.
For ships of unusual form and design (e.g. L/B < 5, B/H $ 2,5, L > 500 m or CB < 0,6) and for ships with a speed of:
v0 > 1,6 @ [kn]
as well as for ships with large bow and stern flare and with cargo on deck in these areas BKI may require determination of
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-88-320.jpg)
![Section 5 - Longitudinal Strength B 5-7/27
wavebendingmomentsaswellastheirdistributionovertheship'slengthbyapprovedcalculationprocedures.Suchcalculation
procedures shall take into account the ship's motions in a natural seaway.
2. Still Water Loads
2.1 General
Due to the provided loading cases the vertical longitudinal
bending moments and shear forces are to be proved by calculations for cases in intact conditions (MSW, QSW) and if required
(see G.1.) for damage conditions (MSWf, QSWf).
If statical torsional moments are likely to be expected from the loading or construction of the ship, they have to be taken
into account.
Still water loads have to be superimposed with the wave induced loads according to 3.
2.2 Guidance values for containerships with irregular loading
2.2.1 Still water bending moments
When determining the required section modulus of the midship section of containerships in the range:
= 0,3 to = 0,55
it is recommended to use at least the following initial value for the hogging still water bending moment :
MSWini = n1 @ c0 @ L2
@ B @ (0,123 ! 0,015 @ CB) [kNm]
n1 = < 1,2
n = according to 2.2.2
MSWini shall be graduated regularly to ship’s ends.
2.2.2 Static torsional moment
The maximum static torsional moment may be determined by:
MST max = [kNm]
CC = maximum permissible cargo capacity of the ship [t]
= n . G
n = maximum number of 20'-containers (TEU) of the mass G the ship can carry
G = mean mass of a single 20'-container [t]
For the purpose of a direct calculation the following envelope curve of the static torsional moment over the ship's length
is to be taken:
MST = [kNm]
cT1, cT2 = distribution factors, see also Fig. 5.2
cT1 = for
= for
cT2 = for
= for
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-89-320.jpg)
![B Section 5 - Longitudinal Strength5-8/27
Fig. 5.2 - Distribution factors cT1 and cT2 for torsional moments
3. Wave induced loads
3.1 Vertical wave bending moments
The vertical wave bending moment are to be determined according to the following formulae:
MWV= L2
@ B @ c0 @ c1 @ cL @ cM [kNm]
c0,cL = see Section 4,A.2.2
c1 = hogging/sagging condition as follows:
c1H = 0,19 @ CB for hogging condition
c1S = S 0,11 (CB + 0,7) for sagging condition
cM = distribution factor, see also Fig. 5.3
cMH = hogging condition
= for 0 < 0,4
= 1,0 for 0,4 0,65
= for 0,65 < 1
cMS = sagging condition
= cv @ for 0 < 0,4
= cv for 0,4 0,65 @ cv
= for 0,65 @ cv < 1
Fig. 5.3 - Distribution factor cM and influence factor cv
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-90-320.jpg)
![Section 5 - Longitudinal Strength B 5-9/27
cv = influence with regard to speed v0 of the vessel
= 1,0 for L the value need not be less than 100
= 1,0 for damaged condition.
3.2 Vertical wave shear forces
The vertical wave shear forces are to be determined by the following formulae:
QWV = c0 @ cL @ L @ B (CB + 0,7) cQ [kN]
c0, cL = see Section 4, A.2.2
cQ = distribution factor according to Table 5.1, see also Fig. 5.4.
m =
c1H, c1S = see 3.1.
Table 5.1 - Distribution factor cQ
Range for positive shear forces for negative shear forces
0 < 0,2 1,38 @ m S 1,38
0,2 < 0,3 0,276 @ m S 0,276
0,3 < 0,4 1,104 m S 0,63 + (2,1 S 2,76 m)
0,4 < 0,6 0,21 S 0,21
0,6 < 0,7 (3 cv – 2,1) + 0,21
0,7 < 0,85 0,3 @ cv S 0,3 m
0,85 # 1,0
Fig 5.4 Distribution factor cQ
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-91-320.jpg)
![B Section 5 - Longitudinal Strength5-10/27
3.3 Horizontal bending moments
MWH = 0,32 @ L @ QWHmax @ cM [kNm]
cM = see 3.1, but for cv = 1
QWHmax = see 3.4
3.4 Horizontal shear forces
QWHmax = [kN]
cN =
cNmin = 2
QWH = QWHmax A cQH
cQH = distribution factor according to Table 5.2, see also Fig. 5.5
Fig 5.5 Distribution factor cQH
Table 5.2 - Distribution factor cQH
Range cQH
1
0,5
1,0
3.5 Torsional moments
The maximum wave induced torsional moment is to be determined as follows :
MWTmax = [kNm]
a =
amin = 0,1
cN = see 3.4
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-92-320.jpg)
![Section 5 - Longitudinal Strength B, C 5-11/27
ZQ = distance [m] between shear centre and a level at above the basis
When a direct calculation is performed, for the wave induced torsional moments the following envelope curve is to be taken:
MWT = [kNm]
cWT = distribution factor, see also Fig. 5.6
=
cT1, cT2 = see 2.2.2
Fig. 5.6 - Distribution factor CWT
Note
The envelope can be approximated by superposition of both distributions according to Fig. 5.2.
C. Section Moduli, Moments of Inertia, Shear and Buckling Strength
1. Section moduli as a function of the longitudinal bending moments
1.1 The section moduli related to deck WD respectively WD’ or bottom WB are not to be less than:
W = [m3
]
fr = 1,0 in general
= according to F.2. for ships with large openings
Fp = permissible longitudinal bending stress [N/mm2
]
= cs @ Fp0
Fp0 = 18,5 for L < 90 m
= for L $ 90 m
cs = 0,5 + for 0 < 0,30
= 1,0 for 0,30 0,70
= for 0,70 < 1,0
1.2 Fortherangesoutside0,4Lamidshipsthefactorcs maybeincreaseduptocs =1,0,ifthisisjustifiedunderconsideration
of combined stresses due to longitudinal hull girder bending (including bending to impact loads), horizontal bending, torsion
and local loads and under consideration of buckling strength.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-93-320.jpg)
![C Section 5 - Longitudinal Strength5-12/27
2. Minimum midship section modulus
2.1 The section modulus related to deck and bottom is not to be less than the following minimum value:
Wmin= k @ c0 @ L2
@ B A(CB + 0,7)A10-6
[m3
]
c0 according to Section 4, A.2.2 for unlimited service range.
For ships classed for a restricted range of service, the minimum section modulus may be reduced as follows:
P (Restricted Ocean Service) : by 5%
L (Coasting Service) : by 15%
T (Shallow Water Service) : by 25%
2.2 The scantlings of all continuous longitudinal members based on the minimum section modulus requirement are
to be maintained within 0,4 L amidships.
3. Midship section moment of inertia
The moment of inertia related to the horizontal axis is not to be less than :
Iy = 3 @ 10-2
@ W @ [m4
]
W see 1.1 and/or 2.1, the greater value is to be taken.
4. Calculation of section moduli
4.1 The bottomsection modulus WB and thedecksectionmodulusWD aretobedeterminedbythefollowing formulae:
WB = [m3
]
WD = [m3
]
Continuous structural elements above eD (e.g. trunks, longitudinal hatch coamings, decks with a large camber, longitudinal
stiffners and longitudinal girders arrangedabovedeck,bulwarkscontributingtolongitudinalstrengthetc.)maybeconsidered
when determining the section modulus, provided they have shear connection with the hull and are effectively supported by
longitudinal bulkheads or by rigid longitudinal or transverse deep girders.
The fictitious deck section modulus is then to be determined by the following formulae :
W’D = [m3
]
e’D = [m]
z = distance [m] from neutral axis of the cross section considered to top of continuous strength member
y = distance [m] from centre line to top of continuous strength member.
It is assumed that e’D > eD.
For ships with multi-hatchways see 5.
4.2 When calculating the section modulus, openings of continuous longitudinal strength members shall be taken into
account. Large openings, i.e. openings exceeding 2,5 m in length or 1,2 m in breadth and scallops, where scallop-welding
is applied, are always to be deducted from the sectional areas used in the section modulus calculation.
Smaller openings (manholes, lightening holes, single scallops in way of seams etc.) need not be deducted provided that the
sumof their breadths or shadow area breadths in one transverse section is not reducing the section modulus at deck or bottom
by more than 3 % and provided that the height of lightening holes, draining holes and single scallops in longitudinals or
longitudinal girders does not exceed 25 % of the web depth, for scallops 75 mm at most. (See fig.5.7.)
A deduction-free sumof smaller openingbreadths in one transverse section in the bottomor deck area of 0,06 (B -Gb) (where
B = breadth of ship at the considered transverse section, Gb = sum of breadth of openings) may be considered equivalent
to the above reduction in section modulus by 3%.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-94-320.jpg)
![Section 5 - Longitudinal Strength C 5-13/27
The shadow area will be obtained by drawing two tangent lines with an opening angle of 30E (see Fig. 5.7).
4.3 Where in the upper and lower flange thicknesses of continuous longitudinal structures forming boundaries of oil
or ballast tanks have been reduced due to arrangement of an effective corrosion protection system, these thickness reduction
shall not result in a reduction of midship section modulus of more than 5%.
Note
In case of large openings local strengthenings may be required which will be considered in each individual case (see also
Section 7, A.3.1).
Fig 5.7 Shadow area
5. Ships with multi-hatchways
5.1 Forthedeterminationofsectionmoduli100%effectivityofthelongitudinalhatchwaygirdersbetweenthe hatchways
may be assumed, if an effective attachment of these girders is given.
5.2 An effective attachment of the longitudinal hatchway girder must fulfil the following condition :
The longitudinal displacement fL of the point of attachment due to action of a standard longitudinal force PL is not to exceed
fL = [mm]
R = length of transverse hatchway girder according to Fig. 5.8 [m]
PL = 10 @ ALG [kN]
ALG = entire cross sectional area of the longitudinal hatchway girder [cm2
]
see also Fig. 5.8.
Where the longitudinal displacement exceeds fL = R/20, special calculation of the effectivity of the longitudinal hatchway
girders may be required.
Fig. 5.8 Ship with multi-hatchways
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-95-320.jpg)
![C Section 5 - Longitudinal Strength5-14/27
5.3 For the permissible combined stress see Section.10, E.3.
6. Shear strength
The shear stress in longitudinal structures due to the vertical transverse forces QT acc. to E.2. and shall not exceed
110/ k [N/mm2
].
For ships with large deck openings and/or for ships with large static torsional moments, also the shear stresses due to MSTmax
have to be considered adversely, i.e. increasing the stress level.
The shear stresses are to be determined according to D.3.
7. Proof of buckling strength
AlllongitudinalhullstructuralelementssubjectedtocompressivestressesresultingfromMT accordingtoE.1andQT according
to E.2. are to be examined for sufficient resistance to buckling according to Section 3, F. For this purpose the following load
combinations are to be investigated :
- MT and 0,7 @ QT
- 0,7 @ MT and QT .
8. Ultimate load calculation of the ship's transverse sections
8.1 Inextremeconditions,largerloadsthanreferredtoinB.mayoccur.Therefore,dimensioningoflongitudinalstructures
is to be verified by proving the ultimate capacity according to 8.2 and 8.3. The calculations are to include those structural
elements contributing to the hull girder longitudinal strength and are to be based on gross scantlings.
The following safety factors are to be assumed:
(R = 1,20
(WV = 1,20
8.2 Ultimate vertical bending moment
MSWf = maximum vertical still water bending moment in flooded conditions [kNm]. For a transverse section under
consideration, the most severe levels of vertical still water bending moments are to be selected from those
cases of flooding used in the damage stability calculations (see Section 36).
cs = stress factor according to 1.1
MU = ultimate vertical bending moments of the ship's transverse section in the hogging (MU,H) and sagging (MU,S)
conditions [kNm]. See 8.2.1.
MUf = ultimateverticalbendingmomentsoftheship'sdamagedtransversesectioninthe hogging (MUf,H) and sagging
(MUf,S) conditions [kNm]. If no assumptions regarding the extent of damage are prescribed, MUf = 6dM @ MU,
where 6dM is a reduction factor for the ultimate moments in damaged conditions (6dM # 1). The reduction
factor 6dM equals 1 unless a smaller value is specified by the owner or shipyard.
8.2.1 Progressive collapse analysis
A progressive collapse analysis is to be used to calculate the ultimate vertical bending moments of a ship's transverse section.
The procedure is to be based on a simplified incremental-iterative approach where the capacities are defined as the peaks
of the resulting moment-curvature curve (M-P) in hogging (positive) and sagging (negative) conditions, i.e. P is the hull
girder curvature [1/m]. See Fig. 5.9.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-96-320.jpg)
![Section 5 - Longitudinal Strength C 5-15/27
Fig. 5.9 Moment-curvature curve
The main steps to be used in the incremental-iterative approach are summarized as follows:
Step 1 The ship's transverse section is to be divided into plate-stiffener combinations (see 8.2.2.2 (a)) and hard corners
(see 8.2.2.2(b)).
Step2 The average stress – averagestrainrelationshipsFCRk-,forall structural elements (i.e. stiffenerplate combinations
and hard corners) are to be defined, where the subscript k refers to the modes 0, 1, 2, 3 or 4, as applicable (see
8.2.2).
Step 3 The initial and incremental value of curvature )P is to be defined by the following formula :
ReH = minimum nominal yield point of structural elements in the strength deck [N/mm2
]
zD = z co-ordinate of strength deck at side [m] (see also Fig. 5.1)
zNA,e = z co-ordinate of elastic neutral axis for the ship's transverse section [m]
Step 4 For the value of curvature, Pj = Pj-1 + )P, the average strain ,+i,j = Pj zi and corresponding average stress Fi,j is to
be defined for each structural element i (see 8.2.2). For structural elements under tension, Fi,j = FCR0 (see 8.2.2.1).
For plate-stiffener combinations under compression, Fi,j = minimum [FCR1, FCR2, FCR3] (see 8.2.2.2 (a)). For hard
corners under compression, Fi,j = FCR4 (see 8.2.2.2 (b)).
zi = z co-ordinate of ith structural element [m] relative to basis, see also Fig. 5.11
Step 5 For the value of curvature, Pj = Pj-1 + )P, the height of the neutral axis zNA,j is to be determined iteratively through
force equilibrium over the ship's transverse section:
m is the number of structural elements located above zNA,j
n is the number of structural elements located below zNA,j
Ai = cross-sectional area of ith
plate-stiffener combination or hard corner
Step 6 For the value of curvature, Pj = Pj-1 + )P, the corresponding bending moment is to be calculated by summing the
contributions of all structural elements within the ship's transverse section :
Steps 4 through 6 are to be repeated for increasing increments of curvature until the peaks in the M-P curve are well defined.
The ultimate vertical bending moments MU,H and MU,S are to be taken as the peak values of the M-P curve.
8.2.2 Average stress - average strain curves
A typical average stress – average strain curve FCRk-g for a structural element within a ship's transverse section is shown in
Fig. 5.10, where the subscript k refers to the modes 0, 1, 2, 3 or 4, as applicable.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-97-320.jpg)
![C Section 5 - Longitudinal Strength5-16/27
Fig. 5.10 - Typical average stress - average strain curve
8.2.2.1 Negative strain (FCRO - g)
The portion of the curve corresponding to negative strain (i.e. tension) is in every case to be based on elasto-plastic behavior
(i.e. material yielding) according to the following :
[N/mm2
]
k = edge function
= –1 for g < –1
= g for –1 # g # 0
, = relative strain
=
gE = element strain
gy = strain at yield stress in the element
=
8.2.2.2 Positive strain
The portion of the curve corresponding to positive strain (i.e. compression)istobebasedonsomemodeofcollapse behaviour
(i.e. buckling) for two types of structural elements; (a) plate-stiffener combinations and (b) hard corners. See Fig. 5.11.
Fig. 5.11 Structural elements
(a) Plate-stiffener combinations (FCR1-g,FCR2-g,FCR3-g)
Plate-stiffener combinations are comprised of a single stiffener together with the attached plating from adjacent plate fields.
Under positive strain, three average stress – average strain curves are to be defined for each plate stiffener combination
based on beam column buckling (FCR1-g), torsional buckling (FCR2-g) and web/flange local buckling (FCR3-g).
(i) Beam column buckling FCR1-g
Thepositivestrainportionoftheaveragestress–average straincurveFCR1-gbasedonbeamcolumnbucklingofplate-stiffener
combinations is described according to the following :
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-98-320.jpg)
![Section 5 - Longitudinal Strength C 5-17/27
M = edge function
= g for 0 # g # 1
= 1 for g >1
6BC = reduction factor
= 1 for 8K # 0,2
= for 8K > 0,2
8K =
kD = (1 + 0,21 (8K – 0,2) + 8K
2
) / 2
a = length of stiffener [mm]
AX = sectional area of stiffener with attached shell plating of breadth (bm,1/2 + bm,2/2) [mm2
]
IX = moment of inertia of stiffener with attached shell plating of breadth (bm,1/2 + bm,2/2) [cm4
]
bm,1, bm,2 = effective breadths of single plate fields on sides 1 and 2 of stiffener [mm] according to Section 3, F.2.2, in
general based on Load Case 1 of Table 3.3, where the reference degree of slenderness is to be defined as
b1, b2= breadths of single plate fields on sides 1 and 2 of stiffener [mm], see also Fig. 5.11
t1, t2 = thicknesses of single plate fields on sides 1 and 2 of stiffener [mm]
AStif = sectional area of the stiffener without attached plating [mm2
]
(ii) Torsional buckling FCR2-g
The positive strain portion of the average stress – average strain curve FCR1-g based on torsional buckling of plate-stiffener
combinations is described according to the following :
6I = reduction factor according to Section 3, F.3.3.
(iii) Web/flange local buckling FCR3 - g
Thepositivestrainportionoftheaveragestress–averagestraincurveFCR3 -gbasedonweb/flangelocalbucklingofplate-stiffener
combinations is described according to the following :
hw,m, bf,m = effective widthofweb/flange plating[mm]accordingtoSection3,F.2.2(generallybasedonLoad Case
3ofTable3.3forflatbarsandflanges,otherwiseLoadCase1)wherethereferencedegreeofslenderness
is to be defined as
hw = web height [mm]
tw = web thickness [mm]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-99-320.jpg)
![C Section 5 - Longitudinal Strength5-18/27
bf = flange breadth, where applicable [mm]
tf = flange thickness, where applicable [mm]
(b) Hard corners (FCR4-g)
Hard corners are sturdy structural elements comprised of plates not lying in the same plane. Bilge strakes (i.e. one curved
plate), sheer strake-deck stringer connections (i.e. two plane plates) and bulkhead-deck connections (i.e. three plane plates)
are typical hard corners. Under positive strain, single average stress – average strain curves are to be defined for hard corners
based on plate buckling (FCR4-g).
( i ) Plate buckling FCR4-g
bm,i = effective breadths of single plate fields [mm] according to Section 3, F.2.2, as applicable, in general based
onapplicableLoadCasesinTable3.3andTable3.4,wherethereferencedegreeofslendernessistobedefined
as
bi = breadth of single plate fields [mm], see also Fig. 5.11
ti = thickness of single plate fields [mm]
n = number of plates comprising hard corner
8.3 Ultimate vertical shear force
QSWf = maximumverticalstillwatershearforceinfloodedconditions[kN].Foratransverse section under consideration,
the most severe levels of vertical still water shear forces are to be selected from those cases of flooding used
in the damage stability calculations (see Section 36).
cs = stress factor according to 1.1
QU = ultimate vertical shear force of the ship's transverse section [Kn]
=
q = number of shear force transmitting plate fields (in general, these are only the vertical plate fields of the ship's
transverse section, e.g. shell and longitudinal bulkhead plate fields)
6Ji = reduction factor of the ith
plate field according to Section 3, F.2.1.
bi = breadth of the ith
plate field [mm]
ti = thickness of the ith
plate field [mm]
ReHi = minimum nominal yield point of the ith
plate field [N/mm2
]
QUf = ultimate vertical shear force of the ship's undamaged transverse section [kN]. If no assumptions regarding
the extent of damage are prescribed, QUf = 6dMQU, where 6dM is a reduction factor for the ultimate force in
damaged conditions (6dM # 1).
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-100-320.jpg)
![D Section 5 - Longitudinal Strength5-20/27
1.2 Permissible stresses
The equivalent stress from FL and JL is not to exceed the following value :
FV = [N/mm2
]
Table 5.3 - Load cases and stress combinations
Load Case Design stresses FL, JL
L1a
FL1a =
JL1a =
L1b
FL1b =
JL1b =
L2a
FL2a =
JL2a =
L2b
FL2b =
JL2b =
L3a
FL3a =
JL3a =
L3b
FL3b =
JL3b =
L1a,b = Load caused by vertical bending and static torsional moment.
L2a,b = Load caused by vertical and horizontal bending moment as well as static torsional moment.
L3a,b = Load caused by vertical and horizontal bending moment as well as static and wave induced torsional moment
1.3 Structural design
1.3.1 Ingeneral,longitudinalstructures are tobedesignedsuch,thattheyrunthroughtransversestructures continuously.
Major discontinuities have to be avoided.
If longitudinal structures are to be staggered, sufficient shifting elements shall be provided.
1.3.2 TherequiredweldingdetailsandclassifyingofnotchesresultfromthefatiguestrengthanalysisaccordingtoSection
20.
Within the upper and lower hull girder flange, the detail categories for the welded joints (see Table 20.3) shall not be less
than
)FR min = [N/mm2
]
MWVhog, MWVsag = vertical wave bending moment for hogging and sagging according to B.3.1
n = design lifetime of the ship
20 [years]≥
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-102-320.jpg)
![Section 5 - Longitudinal Strength D 5-21/27
2. Normal stresses in the ship's longitudinal direction
2.1 Normal stresses from vertical bending moments
2.1.1 statical from MSW :
FSW = [N/mm2
]
MSW = still water bending moment according to A.5. at the position x/L
2.1.2 dynamical from MWV :
FWV = [N/mm2
]
2.2 Normal stresses due to horizontal bending moments
dynamical from MWH :
FWH = ! [N/mm2
]
MWH = horizontal wave bending moment according to B.3.3 at the position x/L
Iz = moment of inertia[m4
] of the transverse ship section considered around the vertical axis at the position
x/L
ey = horizontal distance of the structure considered from the vertical, neutral axis [m]
ey is positive at the port side, negative at the starboard side
2.3 Normal stresses from torsion of the ship's hull
When assessing the cross sectional properties the effect of wide deck strips between hatches constraining the torsion may
be considered, e.g. by equivalent plates at the deck level having the same shear deformation as the relevant deck strips.
2.3.1 statical from MSTmax:
For a distribution of the torsional moments according to B.2.2.2, the stresses can be calculated as follows :
FST = [N/mm2
]
MSTmax = max. static torsional moment according to B.2.2.2
see 2.3.2.
For other distributions the stresses have to be determined by direct calculations.
2.3.2 dynamical from MWTmax:
FWT = [N/mm2
]
MWTmax = according to B.3.5
= for 0 # < 0,25CTor
= for 0,25 # # 0,65
= for 0,65 # # 1
IT = sectorial inertia moment [m6
] of the ship's transverse section at the position X/L
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-103-320.jpg)
![D Section 5 - Longitudinal Strength5-22/27
Ti = sectorial coordinate [m2
] of the structure considered
8 = warping value
= [l/m]
IT = torsional moment of inertia [m4
] of the ship's transverse section at the position x/L
e = Euler number (e = 2,718...)
a =
Rc = characteristical torsion length [m]
= for < 5,284
= for > 5,284
Cc = for 0 # # 0,4 and 0 # # 0,4
= 1 for 0,4 # # 0,55
= for 0,55 < # 1
xA = 0 for ships without cargo hatches
= distance [m] between the aft end of the length L and the aft edge of the hatch forward of the engine
room front bulkhead on ships with cargo hatches, see also Fig. 5.13
3. Shear stresses
Shear stress distribution shall be calculated by calculation procedures approved by BKI. For ships with multi-cell transverse
cross sections (e.g. double hull ships), the use of such a calculation procedure, especially with non-uniform distribution of
the load over the ship's transverse section, may be stipulated.
3.1 Shear stresses due to vertical shear forces
For ships without longitudinal bulkheads or with two longitudinal bulkheads,the distribution of the shear stress in the shell
and in the longitudinal bulkheads can be calculated with the following formulae:
statical from QSW :
JSW =
dynamical from QWV :
JWV =
Sy(z)= first moment of the sectional area considered [m3
], above or below, respectively, the level z considered,
and related to the horizontal, neutral axis
t = thickness of side shell or longitudinal bulkhead plating[mm] at the section considered
" = 0 for ships having no longitudinal bulkhead
If 2 (two) longitudinal bulkheads are arranged :
" = 0,16 + 0,08 for the longitudinal bulkheads
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-104-320.jpg)
![D, E Section 5 - Longitudinal Strength 5-23/27
= 0,34 - 0,08 for the side shell
As = sectional area of side shell plating [m2
] within the depth H
AL = sectional area of longitudinal bulkhead plating [m2
] within the depth H.
For ships of normal shape and construction, the ratio S/Iy determined for the midship section can be used for all sections.
3.2 Shear stresses due to horizontal shear forces
3. is to be applied to correspondingly.
3.3 Shear stresses due to torsional moments
statical from MSTmax :
For a distribution of torsional moments according to B.2.2.2, the stresses can be calculated as follows:
[N/mm2
]
CTor = according to D.2.3.1
MSTmax = according to B.2.2.2
MWTmax = according to B.3.5
IT = according to D.2.3.1
STi = statical sector moment [m4
] of the structure considered
ti = thickness[mm] of the plate considered
For other distributions the stresses have to be determined by direct calculations.
dynamical from MWTmax:
= [N/mm2
]τWT C M
S
I t
Tor WT
i
i
. .
.
max
ω
ω
E. Permissible Still Water Loads
1. Vertical bending moments
Thepermissiblestillwaterbendingmomentsforany sectionwithinthelengthLaretobedeterminedbythefollowingformulae:
MSW = MT S MWV [kNm]
MWV see B.3.1
For harbour- and offshore terminal conditions the wave loads may be multiplied with the following factors:
— harbour conditions (normally) : 0,1
— offshore terminal conditions : 0,5
From the following two values for MT :
MT = FD @ WD(a) @ [kNm]
or
MT = FB @ WB(a) @ [kNm]
the smaller value is to be taken.
WD(a), WB(a) = actual section modulus in the deck or bottom, respectively
FD, F’D = longitudinal bending stress [N/mm2
] for the ship’s upper hull girder flange
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-105-320.jpg)
![E Section 5 - Longitudinal Strength5-24/27
= FSW + FWV
FB = longitudinal bending stress [N/mm2
] for the ship’s lower hull girder flange
= FSW + FWV
FSW, FWV longitudinal stress according to D.2.
fr = 1,0 (in general).
= according to F.2. for ships with large deck openings
In the range x/L = 0,3 to x/L = 0,7 the permissible still water bending moment should generally not exceed the value obtained
for x/L = 0,5.
2. Vertical shear forces
ThepermissiblestillwatershearforcesforanycrosssectionwithinthelengthLaretobedeterminedbythefollowingformulae:
QSW = QT S QWV [kN]
QT = permissible total shear force [kN], for which the permissible shear stress J = JSW + JWV will be reached
but not exceeded at any point of the section considered.
J = permissible shear stress [N/mm2
]
QWV = according to B.3.2
For harbour and offshore terminal conditions, see 1.
2.1 Correction of still water shear force curve
In casse with empty cargo hold, the conventional shear force curvemaybecorrected according to the direct load transmission
by the longitudinal bottom structure at the transverse bulkheads. See also Fig. 5.12.
2.2 Thesupportingforcesofthebottomgrillageatthetransversebulkheadsmayeitherbedeterminedbydirect calculation
or by approximation, according to 2.3.
Fig. 5.12 Correction of the shear force curve
2.3 Thesumofthesupportingforcesofthebottomgrillageattheaftorforwardboundarybulkheadofthehold considered
may be determined by the following formulae:
)Q = u @ P S v @ T* [kN]
P = mass of cargo or ballast [t] in the hold considered, including any contents of bottom tanks within the flat
part of the double bottom
T* = draught [m] at the centre of the hold
u, v = correction coefficients for cargo and buoyancy as follows:
u = [kN/t]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-106-320.jpg)
![Section 5 - Longitudinal Strength E, F 5-25/27
v = 10 @ 6 @ R @ b [kN/m]
6 =
R = length of the flat part of the double bottom [m]
b = breadth of the flat part of the double bottom [m]
h = height of the hold [m]
V = volume of the hold [m3
].
3. Static torsional moments
The permissible static torsional moments have to be determined on the basis of the design stresses in Table 5.3. together
with the formula in D.2.3.1.
3.1 For ships with torsional moments according to B.2. it has to be proved by means of the loading computer, that
the maximum permissible values are exceeded at no location. Excess values are permissible, if the actual torsional moments
at the adjacent calculation points are correspondingly less than the permissible values.
3.2 Unless shown by a particular proof, during loading and unloading the static torsional moments shall not be higher
than 75 % of the wave induced torsional moment according to B.3.5.
F. Guidance Values for Large Deck Openings
1. General
1.1 Displacements of the upper hull girder flange mainly caused by torsional loads, induce additional local bending
moments and forces acting in the deck strips. These moments act about the z-axis, see Fig. 5.1. After consultation with BKI
stresses resulting from that have to be calculated for longitudinal and transverse girders and to be taken into account for the
design.
The calculation of these stresses can be dispensed with, if the guidance values according to 2. and 3. are observed.
1.2 A ship is regarded as one with large deck openings if one of the following conditions applies to one or more hatch
openings:
.1 > 0,6
.2 > 0,7
bL = breadth of hatchway, in case of multi hatchways, bL is the sum of the individual hatchway-breadths
RL = length of hatchway
BM = breadth of deck measured at the mid length of hatchway
RM = distancebetweencentresoftransversedeckstripsateachendofhatchway.Wherethereisnofurtherhatchway
beyond the one under consideration, RM will be specially considered.
2. Guidance values for the determination of the section modulus
The section moduli of the transverse sections of the ship are to be determined according to C.1. and C.2.
The factor fr amounts to:
according to D. for the ship's upper respectively lower girder. The greater value is to be taken.σ σ σL SW WV1, ,
The calculation of the factor fr may be dispensed with, if fr is selected according to Fig. 5.13.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-107-320.jpg)
![F Section 5 - Longitudinal Strength5-26/27
Fig. 5.13 - Correction factor fr and distribution factor cu
3. Guidance values for the design of transverse box girders of container ships
The scantlings of the transverse box girders are to be determined by using the following design criteria :
– support forces of hatch covers, see Section 17, B.4.5 - B.4.7.
– support forces of the containers stowed in the hold place (e.g. due to longitudinal acceleration)
– stresses due to the torsional deformations of the hull,
– stresses resulting from the water pressure, if the transverse box girder forms part of a watertight bulkhead, see
Section 11.
In general the plate thickness shall not be less than obtained from the following formulae (see also Fig. 5.14) :
t1 = [mm] : or
t1 = 0,5 t0 [mm]
t0 = thickness of longitudinal hatch coaming or of the uppermost strake of the longitudinal bulkhead
t2 = 0,85 [mm] : or
t2 = 12 @ a [mm]
a = spacing of stiffeners [m].
The larger of the values t1 or t2 is to be taken. L need not be taken greater than 200 m.
For coamings on the open deck see also Section 17, B.1.
Fig. 5.14 Plate thickness of the transverse box girder
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-108-320.jpg)
![Section 5 - Longitudinal Strength F, G 5-27/27
4. Guidance values for the displacements of the upper girder of the ship
Ingeneral,therelativedisplacement)ubetweentheshipsidesistobedetermined bydirectcalculations.Forthedimensioning
of hatch cover bearings and seals, the following value may be used for the displacement:
= [mm]Δu
MSTmax, MWTmax according to B.2.2.2 or B.3.5, respectively
cu = distribution factor according to Fig. 5.13
cA = value for cu at the aft part of the open region, see also Fig. 5.13
=
xA = according to D.2.3.1; for xA no smaller value than 0,15 L and no greater value than 0,3 L is to be taken.
G. Bulk Carriers
1. General
In addition to the requirements of B., for all bulk carriers with the Notation BC-A or BC-B according to Section 23, F.2.1,
the longitudinal strength is to be checked to be adequate for specified flooded conditions, in each of the cargo and ballast
conditions considered in the intact longitudinal strength calculations. The loading conditions ''harbour'', ''docking, afloat'',
''loading and unloading transitory conditions'' as well as ''ballast water exchange'' need not be considered.
The required moment of inertia according to C.3. and the strength of local structural members are excluded from this proof.
For accessibility see Section 1, D.1.
2. Flooding criteria
To calculate the weight of ingressing water, the following assumptions are to be made:
– The permeability of empty cargo spaces and volume left in loaded cargo spaces above any cargo is to be taken
as 0,95.
– Appropriatepermeabilitiesandbulkdensitiesaretobeusedforanycargocarried.Forironore,aminimum permeability
of 0,3 with a corresponding bulk density of 3,0 t/m3
is to be used. For cement, a minimum permeability of 0,3
with a corresponding bulk density of 1,3 t/m3
is to be used. In this respect, "permeability" for solid bulk cargo
means the ratio of the floodable volume between the cargo parts to the gross volume of the bulk cargo.
– For packed cargo conditions (such as steel mill products), the actual density of the cargo should be used. The
permeability has to be harmonized case by case (pipes, flat steel, coils etc.) with BKI.
3. Flooding conditions
Each cargo hold is to be considered individually flooded up to the equilibrium waterline. This does not apply for cargo holds
of double hull construction where the double hull spacing exceeds 1 000 mm, measured vertically to the shell at any location
of the cargo hold length.
The wave induced vertical bending moments and shear forces in the flooded conditions are assumed to be equal to 80 %
of the wave loads, as given in B.3.1. and B.3.2.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-109-320.jpg)
![Section 6 - Shell Plating A, B 6-1/20
Section 6
Shell Plating
A. General, Definitions
1. General
1.1 Theapplicationofthedesignformulae giveninB.1.2andC.1.2toships ofless than90minlengthmaybeaccepted
when a proof of longitudinal strength has been carried out.
1.2 Theplatethicknessesaretobetaperedgradually,ifdifferent.Gradualtaperisalsotobeeffectedbetweenthethicknesses
required for strengthening of the bottom forward as per E.2. and the adjacent thicknesses.
2. Definitions
k = material factor according to Section 2, B.2.
pB, pB1 = load on bottom [kN/m2
] according to Section 4, B.3.
ps, ps1 = load on sides [kN/m2
] according to Section.4, B.2.1
pe = design pressure for the bow area [kN/m2
] according to Section 4, B.2.2 or according to Section 4, B.2.3
for the stern area as the case may be
pSL = design slamming pressure [kN/m2
] according to Section 4, B.4.
nf = 1,0 for transverse framing
= 0,83 for longitudinal framing
FLB = Maximum bottom design hull girder bending stress [N/mm2
] according to Section 5, D.1.
FLS = maximumdesignhullgirderbendingstressinthesideshellatthestationconsideredaccordingtoSection
5, D.1. [N/mm2
].
JL = maximum design shear stress due to longitudinal hull girder bending [N/mm2
], according to Section
5, D.1.
Fperm= permissible design stress [N/mm2
]
= [N/mm2
] for L < 90 m
= [N/mm2
] for L 90 m
tK = corrosion addition according to Section 3, K.
B. Bottom Plating
1. Plate thickness based on load stress criteria
1.1 Ships with lengths L < 90 m
The thickness of the bottom shell plating within 0,4 L amidships is not to be less than :
tB1 = [mm]
Within0,1LforwardoftheaftendofthelengthLandwithin 0,05L aft of F.P. the thickness is not to beless thantB2 according
to 1.2.
1.2 Ships with length L > 90 m
The thickness of the bottom plating is not to be less than the greater of the two following values :
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-111-320.jpg)
![B Section 6 - Shell Plating6-2/20
tB1 = [mm]
tB2 = [mm]
FPR = [N/mm2
]
Note :
As a first approximation FLB and JL may be taken as follows:
FLB = [N/mm2
] for L < 90 m
= [N/mm2
] for L 90 m
JL = 0
2. Critical plate thickness, buckling strength
2.1 Guidance values for critical plate thickness
For ships, for which proof of longitudinal strength is required or carried out respectively, the following guidance values
for the critical plate thickness are recommended:
for FLB 0,6 @ ReH :
tcrit = [mm]
for FLB > 0,6 @ ReH :
tcrit = [mm]
c = 0,5 for longitudinal framing
= for transverse framing
" = aspect ratio a/b of plate panel considered (see Section 3, F. 1.)
FLB = largest compressive stress in the bottom due to longitudinal hull girder bending
Fl = see Section 3, F.1. (Table 3.2)
= 1,0 for longitudinal framing.
2.2 Buckling strength
Theguidancevaluesobtainedfrom2.1aretobeverifiedaccordingtoSection3,F.Section5,C.6.applieswheresolelylongitudinal
hull girder bending stress need to be considered. Section 8, B.8. applies where the combined action of longitudinal hull girder
bending and local loads has to be considered.
3. Minimum thickness
At no point the thickness of the bottom shell plating shall be less than :
tmin = [mm] for L < 50 m
= [mm] for L 50 m
tmax = 16,0 mm in general
or bulk carriers see Section 23, B.5.3, for tankers see Section 24, A.14.
4. Bilge strake
4.1 The thickness of the bilge strake is to be determined as required for the bottom plating according to 1.
The thickness so determined is to be verified for sufficient buckling strength according to the requirements of Section 5,
C.6.. and Section 3, F., see Table 3.4, load cases 1a, 1b, 2 and 4.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-112-320.jpg)
![Section 6 - Shell Plating B 6-3/20
If this verification shows that a smaller thickness than that of the bottom plating is possible, such smaller thickness may
be permitted.
4.2 If according to Section 2, B. a higher steel grade than A/AH is required for the bilge strake, the width of the bilge
strake is not to be less than:
b = 800 + 5 @ L [mm]
4.3 At the end of the curved bilge strake longitudinal stiffeners or girders are to be arranged. When the stiffeners are
arranged outside the bilge radius sufficient buckling resistance according to Section 3, F. is to be shown for the plane plate
fields
taking into account the stresses according to Section 5, D.1 and the compression stresses
Fq = [N/mm2
]
acting coincidently in the transverse direction.
The thickness of these plate fields shall not be less than the thickness derived from 1., 3. and C.1. respectively.
For the frame spacing a and the field length R, aL and bL + R/4 are to be taken accordingly, see sketch.
aL = spacing of the floors or transverse stiffeners respectively [mm]
bL = distance of the longitudinal stiffener from the end of corner radius [mm]
R = bilge radius [mm]
p = ps, ps1 or pB1 at the end of corner radius or pSL according to Section 4, B.4.1 as the case may be [kN/m2
].
t = plate thickness [mm]
Ifthederivedthicknessfortheplaneplatefield is larger than that for the curved bilge strake accordingto4.1thereinforcement
is to be expanded by a minimum of R/6 into the radius.
5. Flat plate keel and garboard strake
5.1 The width of the flat plate keel is not to be less than:
b = 800 + 5 @ L [mm]
The thickness of the flat plate keel is not to be less than:
tFK = tB + 2,0 [mm]
within 0,7 L amidships and in way of the engine seating
= tB [mm] otherwise
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![B, C Section 6 - Shell Plating6-4/20
tB = thickness of the bottom plating [mm] according to 1. – 3.
5.2 Forshipsexceeding100minlength,thebottomofwhichislongitudinallyframed,theflatplatekeelistobestiffened
byadditionallongitudinalstiffenersfittedatadistanceofapprox.500mmfromcentreline.Thesectionalareaofonelongitudinal
stiffener should not be less than 0,2 L [cm2
].
5.3 Where a bar keel is arranged, the adjacent garboard strake is to have the scantlings of a flat plate keel.
C. Side Shell Plating
1. Plate thickness based on load stress criteria
1.1 Ships with lengths L < 90 m
The thickness of the side shell plating within 0,4 L amidship is not to be less than:
tS1 = [mm]
Within0,1LforwardoftheaftendofthelengthLandwithin0,05 L aft of F.P. the thickness is not to be less than tS2 according
to 1.2.
1.2 Ships with lengths L 90 m
The thickness of the side shell plating is not to be less than the greater of the following values:
tS1 = [mm]
tS2 = [mm]
tS3 = [mm]
FpR = [N/mm2
]
FpRmax= [N/mm2
]
p = ps or pe as the case may be
Note :
As a first approximation FLS and JL may be taken as follows:
FLS = 0,76 @ FLB [N/mm2
]
JL = [N/mm2
]
FLB = see B.1.2.
1.3 In way of large shear forces, the shear stresses are to be checked in accordance with Section 5,D.
2. Minimum thickness
For the minimum thickness of the side shell plating B.3. applies accordingly.
Abovealevel T+c0/2abovebaselinesmallerthicknessesthan tmin may be accepted if the stress level permits such reduction.
For c0 see Section 4, A.2.2.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-114-320.jpg)
![Section 6 - Shell Plating C 6-5/20
3. Sheerstrake
3.1 The width of the sheerstrake is not to be less than:
b = 800 + 5 @ L [mm]
bmax = l800 [mm]
3.2 The thickness of the sheerstrake shall, in general, not be less than the greater of the following two values:
t = 0,5 (tD + tS) [mm]
= tS [mm]
tD = required thickness of strength deck
tS = required thickness of side shell.
3.3 Where the connection of the deck stringer with the sheerstrake is rounded, the radius is to be at least 15 times the
plate thickness.
3.4 Welds on upper edge of sheerstrake are subject to special approval.
Regarding welding between sheerstrake and deck stringer see Section 7, A.2.
Holes for scuppers and other openings are to be carefully rounded, any notches shall be avoided.
4. Buckling strength
For ship for which proof of longitudinal strength is required or carried out proof of buckling strength of the side shell is to
be provided in accordance with the requirements of Section 5, C.6. and Section.3,.F.
5. Strengthenings for harbour and tug manoeuvres
5.1 In those zones of the side shell which may be exposed to concentrated loads due to harbour manoeuvres the plate
thickness is not to be less than required by 5.2. These zones are mainly the plates in way of the ship's fore and aft shoulder.
The exact locations where the tugs shall push are to be defined in the building specification. They are to be identified in
the shell expansion plan. The length of the strengthened areas shall not be less tha n approximately 5 m. The height of
the strengthened areas shall extend from about 0,5 m above ballast waterline to about 4,0 m above load water line.
Forshipsof100minlengthandoveratleastonestrengthenedareaistobeprovidedamidshipsinadditiontothetwostrengthened
areas at the ship's shoulders.
Where the side shell thickness so determined exceeds the thickness required by 1. - 3. it is recommended to specially mark
these areas.
5.2 The plate thickness in the strengthened areas is to be determined by the following formulae:
t = [mm]
PfR = local design impact force [kN]
= D/100 [kN] with a minimum of 200 kN and a maximum of 1000 kN
D = displacement of the ship [t].
Any reductions in thickness for restricted service are not permissible.
5.3 In the strengthened areas the section modulus of side longitudinals is not to be less than:
W = [cm3
]
R = unsupported span of longitudinal [m].
5.4 Tween decks, transverse bulkheads, stringer and transverse walls are to be investigated for sufficient buckling
strengthagainstloadsactingintheship's transversedirection. For scantlings of side transverses supporting side longitudinals
see Section 9, B.4.4.
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![D, E Section 6 - Shell Plating6-6/20
D. Side Plating of Superstructures
1. The side plating of effective superstructures is to be determined according to C.
2. The side plating of non-effective superstructures is to be determined according to Section 16.
3. For the definition of effective and non-effective superstructures see Section 16, A.1. For strengthening at ends
of superstructures see Section.16, A.3.
E. Strengthening of Bottom Forward
1. Arrangement of floors and girders
1.1 For the purpose of arranging floors and girders the following areas are defined:
! forward of for L 100 m
! forward of for 100 < L 150 m
! forward of for L > 150 m
1.2 In case of transverse framing, plate floors are to be fitted at every frame. Where the longitudinal framing system
or the longitudinal girder system is adopted the spacing of plate floors may be equal to three transverse frame spaces.
1.3 In case of transverse framing, the spacing of side girders is not to exceed L/250 + 0,9 [m], up to a maximum of
1,4 m. In case of longitudinal framing, the side girders are to be fitted not more than two longitudinal frame spacings apart.
1.4 Distances deviating from those defined in 1.2 and 1.3 may be accepted on the basis of direct calculations.
1.5 Within the areas defined in 1.1 any scalloping is to be restricted to holes for welding and for limbers.
2. Bottom plating forward of = 0,5
2.1 The thickness of the bottom plating of the flat part of the ship's bottom up to a height of 0,05 @ Tb or 0,3 m above
base line, whichever is the smaller value, is not to be less than:
t = 0,9 @ f2 @ a + tK [mm]
Tb = smallest design ballast draft at the forward perpendicular [m].
f2 = see Section 3, A.3.
2.2 Above0,05Tb or 0,3m abovebaselinetheplatethicknessmaygraduallybetaperedtotherulethicknessdetermined
according to B. For ships with a rise of floor the strengthened plating shall at least extend to the bilge curvature.
3. Stiffeners forward of
3.1 The section modulus of transverse or longitudinal stiffeners is not to be less than:
W = 0,155 @ pSL @ a @ R2
@ k [cm3
].
3.2 The shear area of the stiffeners is not to be less than:
A = 0,028 @ pSL @ a (R n 0,5 @ a) k [cm2
].
The area of the welded connection has to be at least twice this value.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-116-320.jpg)
![Section 6 - Shell Plating F,G 6-7/20
F. Strengthenings in Way of Propellers and Propeller Shaft Brackets, Bilge Keels
1. Strengthenings in way of propellers and propeller brackets
1.1 The thickness of the shell plating in way of propellers is to be determined according to C.
Note
It is recommended that plate fields and stiffenersofshell structures inthevicinityofthepropeller(s)bespeciallyconsidered
from a vibration point of view (see also Section 8, A.1.2.1 and Section 12, A.8). For vessels with a single propeller, plate
fields and stiffeners within dr = 3 should fulfil the following frequency criteria:
for " $ 60E :
for " < 60E :
" = flareangleofframesectioninpropeller planemeasured between a vertical line andthetangentto the bottom
shell plating
fplate = lowestnaturalfrequencyofisotropicplatefieldunderconsiderationofadditionaloutfitting and hydrodynamic
masses [Hz]
fstiff = lowest natural frequency of stiffener under consideration of additional outfitting and hydrodynamic masses
[Hz]
dr = ratio
r = distance of plate field or stiffener to 12 o'clock propeller blade tip position [m]
dp = propeller diameter [m]
fblade = propeller blade passage excitation frequency at n [Hz]
= [Hz]
n = maximum propeller shaft revolution rate [1/min]
z = number of propeller blades
1.2 In way of propeller shaft brackets, Section 19, B.4.3 has to be observed
1.3 Wherepropellerrevolutionsareexceeding300rpm(approx.),particularlyincaseofflatbottomsintercostalcarlings
are to be fitted above or forward of the propeller in order to reduce the size of the bottom plate panels (see also Section 8,
A. 1.2.3.4).
2. Bilge keels
2.1 Where bilge keels are provided they are to be welded to continuous flat bars, which are connected to the shell
plating with their flat side by means of a continuous watertight welded seam, see bottom of Fig. 6.1.
2.2 The ends of the bilge keels are to have soft transition zones according to Fig. 6.1, top. The ends of the bilge keels
shall terminate above an internal stiffening element.
2.3 Any scallops or cut-outs in the bilge keels are to be avoided.
G. Openings in the Shell Plating
1. General
1.1 Where openings are cut in the shell plating for windows or side scuttles, hawses, scuppers, sea valves etc., they
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-117-320.jpg)
![Section 6 - Shell Plating H 6-9/20
The requirements are not applicable to high speed, light displacement craft as defined in the IMO Code of Safety for High
Speed Craft.
1.1.2 Two types of bow door are covered by these requirements:
S Visor doors opened by rotating upwards and outwards about a horizontal axis through two or more hinges located
near the top of the door and connected to the primary structure of the door by longitudinally arranged lifting arms.
S Side-opening doors opened either by rotating outwards about a vertical axis through two or more hinges located
near the outboard edges or by horizontal translation by means of linking arms arranged with pivoted attachments
to the door and the ship. It is anticipated that side-opening bow doors are arranged in pairs.
Other types of bow door will be specially considered in association with the applicable requirements of these Rules.
1.2 Arrangement
1.2.1Bow doors are to be situated above the free-board deck. A watertight recess in the freeboard deck located forward of
the collision bulkhead and above the deepest waterline fitted for arrangement of ramps or other related mechanical devices,
may be regarded as a part of the freeboard deck for the purpose of this requirement
1.2.2An inner door is to be provided. The inner door is to be part of the collision bulkhead. The inner door needs not be fitted
directly above the collision bulkhead below, provided it is located within the limits specified in Section 11, A.2.1 for the
position of the collision bulkhead. A vehicle ramp may be arranged for this purpose, provided its position complies with
Section 11, A.2.1. If this is not possible, a separate inner weatherthight door is to be installed, as far as practicable within
the limits specified for the position of the collision bulkhead.
1.2.3Bowdoors are tobe so fittedastoensuretightnessconsistentwithoperationalconditionsandtogiveeffective protection
to inner doors. Inner doors forming part of the collision bulkhead are to be weathertight over the full height of the cargo space
and arranged with fixed sealing supports on the aft side of the doors.
1.2.4Bow doors and inner doors are to be so arranged as to preclude thepossibilityofthe bowdoor causing structuraldamage
to the inner door or to the collision bulkhead in the case of damage to or detachment of the bow door. If this is not possible,
a separate inner weathertight door is to be installed, as indicated in 1.2.2.
1.2.5Therequirementsforinnerdoorsarebasedontheassumptionthatthevehiclesareeffectivelylashedandsecuredagainst
movement in stowed position.
1.3 Definitions
Securing device is a device used to keep the door closed by preventing it from rotating about its hinges.
Supporting device is a device used to transmit external or internal loads from the door to a securing device and from the
securing device to the ship’s structure, or a device other than a securing device, such as a hinge, stopper
or other fixed device, that transmits loads from the door to the ship’s structure.
Locking device is a device that locks a securing device in the closed position.
2. Strength criteria
2.1 Primary structure and securing and supporting devices
2.1.1Scantlings of the primary members, securing and supporting devices of bow doors and inner doors are to be so designed
that under the design loads defined in 3. the following stresses are not exceeded:
bending stress:
F = [N/mm2
]
shear stress:
J = [N/mm2
]
equivalent stress:
Fv = [N/mm2
]
where k is the material factor as given in Section 2, B.2.1, but is not to be taken less than 0,72 unless a fatigue analysis is
carried out according to Section 20.
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![H Section 6 - Shell Plating6-10/20
2.1.2The buckling strength of primary members is to be verified according to Section 3, F.
2.1.3For steel to steel bearings in securing and supporting devices, the nominal bearing pressure calculated by dividing the
design force by the projected bearing area is not to exceed 0,8 x ReH, where ReH is the yield stress of the bearing material.
Forotherbearingmaterials,thepermissiblebearingpressureistobedeterminedaccordingtothemanufacturer’sspecification.
2.1.4The arrangement of securing and supporting devices is to be such that threaded bolts do not carry support forces. The
maximum tension stress in way of threads of bolts not carrying support forces is not to exceed 125/k [N/mm2
].
3. Design loads
3.1 Bow doors
3.1.1The design external pressure to be considered for the scantlings of primary members of bow doors is not to be less than
the pressure specified in Section 4, B.2, but is not to be taken less than :
pe = @ [kN/m2
]
vo = ship's speed [kn] as defined in Section 1, H.5
L = ship's length [m], L 200 m
cRW = service range coefficient according to Section.4, A.2.2
cH = for L < 80 m
= 1,0 for L 80 m
" = flare angle at the point to be considered, defined as the angle between a vertical line and the tangent to the
side shell plating, measured in a vertical plane normal to the horizontal tangent to the shell plating
$ = entryangleatthepointtobeconsidered,definedastheanglebetweenalongitudinallineparalleltothecentreline
and the tangent to the shell plating in a horizontal plane.
See also Fig. 6.2.
Fig. 6.2 Definition angles " and $
3.1.2The design external forces for determining scantlings of securing and supporting devices of bow doors are not to be
less than :
Fx = [kN]
Fy = [kN]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-120-320.jpg)
![Section 6 - Shell Plating H 6-11/20
Fz = [kN]
Ax = area [m2
] of the transverse vertical projection of the door between the levels of the bottom of the door and
the upper deck or between the bottom of the door and the top of the door, whichever is the lesser,
Ay = area [m2
] of the longitudinal vertical projection of the door between the levels of the bottom of the door and
the upper deck or between the bottom of the door and the top of the door, whichever is the lesser,
Az = area [m2
] of the horizontal projection of the door between the levels of the bottom of the door and the upper
deck or between the bottom of the door and the top of the door, whichever is the lesser,
for Ax , Ay and Az see also Fig. 6.3.
h = height[m] of the door between the levels of the bottom of the door and the upper deck or between the bottom
of the door and the top of the door, whichever is the lesser,
R = length [m] of the door at a height h/2 above the bottom of the door,
pe = external design pressure [kN/m2
] as given in 3.1.1 with angles " and $ defined as follows:
" = flare angle measured at the point on the bow door, R/2 aft of the stem line on the plane h/2 above
the bottom of the door, as shown in Fig. 6.2.
$ = entry angle measured at the same point as ".
For bow doors, including bulwark, of unusual form or proportions, e.g. ships with a rounded nose and large stem angles,
the areas and angles used for determination of the design values of external forces may require to be specially considered.
3.1.3For visor doors the closing moment My under external loads is to be taken as:
My = [kN m]
W = mass of the visor door [t]
a = vertical distance [m] from visor pivot to the centroid of the transverse vertical projected area Ax of the visor
door, as shown in Fig.6.3
b = horizontal distance[m] from visor pivot to the centroid of the horizontal projected area Az of the visor door,
as shown in Fig. 6.3
c = horizontal distance[m] from visor pivot to the centre of gravity of visor mass, as shown in Fig. 6.3.
Fig. 6.3 Bow door of visor type
3.1.4Moreover,theliftingarmsofavisordooranditssupportsareto be dimensioned for the staticanddynamicforcesapplied
during the lifting and lowering operations, and a minimum wind pressure of 1,5 kN/m2
is to be taken into account.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-121-320.jpg)
![H Section 6 - Shell Plating6-12/20
3.2 Inner doors
3.2.1The design external pressure pe considered for the scantlings of primary members, securing and supporting devices
and surrounding structure of inner doors is to be taken as the greater of the following:
! pe = 0,45 @ L [kN/m2
] or
! hydrostatic pressure ph = 10 @ h [kN/m2
], where h is the distance [m] from the load point to the top of the
cargo space
Where L is the ship's length, as defined in 3.1.1.
3.2.2The design internal pressure pi considered for the scantlings of securing devices of inner doors is not to be less than:
pi = 25 [kN/m2
]
4. Scantlings of bow doors
4.1 General
4.1.1The strength of bow doors is to be commensurate with that of the surrounding structure.
4.1.2Bow doors are to be adequately stiffened and means are to be provided to prevent lateral or vertical movement of the
doorswhenclosed.Forvisordoorsadequatestrengthfortheopeningandclosingoperationsistobeprovidedintheconnections
of the lifting arms to the door structure and to the ship structure.
4.2 Plating and secondary stiffeners
4.2.1The thickness of the bow door plating is not to be less than the side shell thickness tS2 according to C.1.2, using bow
door stiffener spacing, but in no case less than the required minimum thickness of the shell plating according to C.2.
4.2.2The section modulus of horizontal or vertical stiffeners is not to be less than that required for framing at the position
ofthedooraccordingtoSection9.Considerationis tobe given, wherenecessary,todifferencesinfixitybetweenship'sframes
and bow doors stiffeners.
4.2.3The stiffener webs are to have a net sectional area not less than :
Aw = [cm2
]
Q = shearforce[kN] in the stiffener calculated by usinguniformlydistributedexternaldesignpressurepe asgiven
in 3.1.1
4.3 Primary structure
4.3.1The bow door secondary stiffeners are to be supported by primary members constituting the main stiffening of the door.
4.3.2The primary members of the bow door and the hull structure in way are to have sufficient stiffness to ensure integrity
of the boundary support of the door.
4.3.3Scantlings of the primary members are generally to be verified by direct calculations in association with the external
design pressure given in 3.1.1 and permissible stresses given in 2.1.1. Normally, formulae for simple beam theory may be
applied.
5. Scantlings of inner doors
5.1 General
5.1.1Fordeterminingscantlingsoftheprimarymemberstherequirementsof4.3.3applyinconjunctionwiththeloadsspecified
in 3.2.
5.1.2Where inner doors also serve as vehicle ramps, the scantlings are not to be less than those required for vehicle decks
as per Section 7, B.2.
5.1.3Thedistributionoftheforcesactingonthesecuringandsupportingdevicesisgenerallytobeverifiedbydirectcalculations
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-122-320.jpg)
![Section 6 - Shell Plating H 6-13/20
taking into account the flexibility of the structure and the actual position and stiffness of the supports.
6. Securing and supporting of bow doors
6.1 General
6.1.1Bow doors are to be fitted with adequate means of securing and supporting so as to be commensurate with the strength
and stiffness of the surrounding structure. The hull supporting structure in way of the bow doors is to be suitable for the same
design loads and design stresses as the securing and supporting devices. Where packing is required, the packing material
is to be of a comparatively soft type, and the supporting forces are to be carried by the steel structure only. Other types of
packing may be considered. The maximum design clearance between securing and supporting devices is generally not to
exceed 3 mm.
A means is to be provided for mechanically fixing the door in the open position.
6.1.2Only the active supporting and securing devices having an effective stiffness in the relevant direction are to be included
and considered to calculate the reaction forces acting on the devices. Small and/or flexible devices such as cleats intended
to provide load compression of the packing material are not generally to be included in the calculations called for in 6.2.5.
The number of securing and supporting devices are generally to be the minimum practical whilst taking into account the
redundancy requirements given in 6.2.6 and 6.2.7 and the available space for adequate support in the hull structure.
6.1.3Foropeningoutwardsvisordoors,thepivotarrangementisgenerallytobesuchthatthevisorisselfclosingunderexternal
loads, that is My > 0. Moreover, the closing moment My as given in 3.1.3 is to be not less than:
My0 = [kNm]
6.2 Scantlings
6.2.1Securing and supporting devices are to be adequately designed so that they can withstand the reaction forces within
the permissible stresses given in 2.1.1.
6.2.2For visor doors the reaction forces applied on the effective securing and supporting devices assuming the door as a rigid
body are determined for the following combination of external loads acting simultaneously together with the self weight
of the door:
Case 1 : Fx and Fz ,
Case 2 : 0,7 @ Fy acting on each side separately together with 0,7 @ Fx and 0,7 @ Fz .
The forces Fx , Fy and Fz are to be determined as indicated in 3.1.2 and applied at the centroid of the projected areas.
6.2.3For side-opening doors the reaction forces applied on the effective securing and supporting devices assuming the door
as a rigid body are determined for the following combination of external loads acting simultaneously together with the self
weight of the door:
Case 1 : Fx , Fy and Fz acting on both doors
Case 2 : 0,7 @ Fx and 0,7 @ Fz acting on both doors and 0,7 @ Fy acting on each door separately,
for Fx , Fy and Fz see 6.2.2.
6.2.4Thesupportforcesasdeterminedaccordingto6.2.2and6.2.3shallgenerallyresultinazeromomentaboutthetransverse
axis through the centroid of the area Ax .
For visor doors, longitudinal reaction forces of pin and/or wedge supports at the door base contributing to this moment are
not to be of the forward direction.
6.2.5The distribution of the reaction forces acting on the securingand supporting devices may require to be verified by direct
calculations taking into account the flexibility of the hull structure and the actual position and stiffness of the supports. This
is, for instance, the case when the bow door is supported statically undetermined.
6.2.6The arrangement of securing and supporting devices in way ofthese securing devices istobedesigned with redundancy
so that in the event of failure of any single securing or supporting device the remaining devices are capable of withstanding
the reaction forces without exceeding by more than 20% the permissible stresses as given in 2.1.
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![H Section 6 - Shell Plating6-14/20
6.2.7For visor doors, two securing devices are to be provided at the lower part of the door, each capable of providing the
fullreactionforce required to prevent opening of the door withinthe permissible stresses given in 2.1.1. The opening moment
M0 to be balanced by this reaction force, is not to be taken less than the greater of the following values:
M01 = [kNm]
M02 = [kNm]
FH = horizontal design force [kN], acting forward in the centre of gravity, FH = 10 × W
d = vertical distance [m] from the hinge axis to the centre of gravity of the door mass, as shown in Fig. 6.3
)x = lever
= 0,25 × e [m]
e = distance[m] as defined in Fig. 6.3
a = distance[m] as defined in 3.1.3
6.2.8Forvisordoors,thesecuringandsupportingdevicesexcludingthehingesaretobecapableofresistingtheverticaldesign
force Fv = Fz – 10 × W [kN] within the permissible stresses given in 2.1.1.
6.2.9All load transmitting elements in the design load path, from door through securing and supporting devices into the ship
structure, including welded connections, are to be of the same strength standard as required for the securing and supporting
devices.
6.2.10 For side-opening doors, thrust bearings are to be provided in way of girder ends at the closing of the two leaves
to prevent one leaf to shift towards the other one under effect of unsymmetrical pressure. An example for a thrust bearing
is shown in Fig. 6.4. Securing devices are to be provided so that each part of the thrust bearing can be kept secured on the
other part. Any other arrangement serving the same purpose may be accepted.
Fig. 6.4 Thrust bearing
7. Arrangement of securing and locking devices
7.1 Systems for operation
7.1.1Securing devices are to be simple to operate and easily accessible.
Securing devices are to be equipped with mechanical locking arrangement (self locking or separate arrangement), or to be
of the gravity type. The opening and closing systems as well as securing and locking devices are to be interlocked in such
a way that they can only operate in the proper sequence.
7.1.2Bow doors and inner doors giving access to vehicle decks are to be provided with an arrangement for remote control,
from a position above the freeboard deck of:
! the closing and opening of the doors, and
! associated securing and locking devices for every door.
Indication of the open/closed position of every securing and locking device is to be provided at the remote control stations.
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![Section 6 - Shell Plating J 6-17/20
2.2 Side shell doors and stern doors are to be so fitted as to ensure tightness and structural integrity commensurate
with their location and the surrounding structure.
2.3 Wherethesillofanysideshelldooris belowtheuppermostloadline,thearrangementistobespecially considered.
In case of ice strengthening see Section 15.
2.4 Doors should preferably open outwards.
3. Strength criteria
The requirements of H.2. apply.
4. Design loads
4.1 The design forces considered for the scantlings of primary members, securing and supporting devices of side shell
doors and stern doors are to be not less than the greater of the following values:
4.1.1 Design forces for securing or supporting devices of doors opening inwards:
external force: Fe = [kN]
internal force: Fi = [kN]
4.1.2 Design forces for securing or supporting devices of doors opening outwards:
external force: Fe = [kN]
internal force: Fi = [kN]
4.1.3Design forces for primary members:
external force: Fe = [kN]
internal force: Fi = [kN]
A = area of the door opening [m2
]
W = mass of the door [t]
Fp = total packing force[kN], where the packing line pressure is normally not to be taken less than 5 N/mm
Fo = the greater of Fc or 5 @ A [kN]
Fc = accidentalforce[kN]due toloose ofcargoetc., tobeuniformlydistributed overthe area Aandnotto be taken
less than 300 kN. For small doors such as bunker doors and pilot doors, the value of Fc may be appropriately
reduced. However, the value of Fc may be taken as zero, provided an additional structure such as an inner
ramp is fitted, which is capable of protecting the door from accidental forces due to loose cargoes
pe = external design pressure determined at the centre of gravity of the door opening and not taken less than:
= ps acc. to Section 4, B.2.1 or:
pe = [kN/m2
] for zG < T
= 25 [kN/m2
] for zG > T
zG = height of centre of area of door above base line [m].
4.2 For stern doors of ships fitted with bow doors, pe is not to be taken less than:
pe = [kN/m2
]
cRW = service range coefficient as defined in Section 4, A.2.2.
cH = see H.3.1.1.
5. Scantlings
5.1 General
The requirements of H.4.1 apply analogously with the following additions :
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![Section 6 - Shell Plating K 6-19/20
K. Bulwarks
1. The thickness of bulwark plating is not to be less than :
t = [mm] for L#100 m
= [mm] for L > 100 m
L need not be taken greater than 200 m. The thickness of bulwark plating forward particularly exposed to wash of sea is
to be equal to the thickness of the forecastle side plating according to Section 16, B.1.
Inwayofsuperstructuresabovethefreeboarddeckabaft0,25L fromF.P.thethickness ofthebulwarkplatingmaybereduced
by 0,5 mm.
2. The bulwarkheightorheight of guard rail is not to be less than 1,0 m, the lesser height may be approved ifadequate
protection is provided.
3. Plate bulwarks are to be stiffened at the upper edge by a bulwark rail section.
4. The bulwark is to be supported by bulwark stays fitted at every alternate frame. Where the stays are designed as
per Fig. 6.5, the section modulus of their cross section effectively attached to the deck is not to be less than:
W = 4 @ p q e q R2
[cm3
]
p = ps or pe as the case may be
pmin = 15 kN/m2
e = spacing of stays [m]
R = length of stay [m]
The dimension for calculation of W are to be taken vertical of the plating starting from the base of the stays.
In addition Section 3, E.2.3. must be considered.
The stays are to be fitted above deck beams, beam knees or carlings. It is recommended to provide flat bars in the lower part
which are to be effectively connected to the deck plating. Particularly in ships the strength deck of which is made of higher
tensile steel, smooth transitions are to be provided at the end connection of the flat bar faces to deck.
5. On ships carrying deck cargo, the bulwark stays are to be effectively connected to the bulwark and the deck. The
stays are to be designed for a load at an angle of heel of 30E. Under such loads the following stresses are not to be exceeded:
bending stress:
Fb = [N/mm2
]
shear stress:
J = [N/mm2
]
For loads caused by containers and by stow and lashing arrangements. See also Section 21, G.
6. Anadequatenumberofexpansionjointsistobeprovidedinthebulwark.Inlongitudinaldirectionthestaysadjacent
to the expansion joints shall be as flexible as practicable.
The number of expansion joints for ships exceeding 60 m in length should not be less than:
n = , but need not be greater than n = 5.
7. Openings in the bulwarks shall have sufficient distance from the end bulkheads of superstructures. For avoiding
cracks the connection of bulwarks to deckhouse supports is to be carefully designed.
8. For the connection of bulwarks with the sheer strake C.3.4 is to be observed.
9. Bulwarks are to be provided with freeing ports of sufficient size. See also Section 21, D. 2 and ICLL.
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![Section 7 - Decks A 7-1/9
Section 7
Decks
A. Strength Deck
1. General, Definition
1.1 The strength deck is:
.1 the uppermost continuous deck which is forming the upper flange of the hull structure,
.2 a superstructure deck which extends into 0,4 L amidships and the length of which exceeds 0,15L,
.3 a quarter deck or the deck of a sunk superstructure which extends into 0,4 L amidships.
At the option of the designer the deck below superstructure deck may be taken as strength deck.
1.2 In way of a superstructure deck which is to be considered as a strength deck, the deck below the superstructure
deck istohave thesamescantlingsasa2nd
deck,andthedeckbelowthisdeckthesamescantlingsasa3rd
deck.Thethicknesses
ofastrengthdeckplatingare tobeextended into the superstructure for a distance equal to the width of the deckplatingabreast
the hatchway. For strengthening of the stringer plate in the breaks, see Section 16, A.3.
1.3 If the strength deck is protected by sheathing a smaller corrosion addition tK than required by Section 3, K may
be permitted. Where a sheathing other than wood is used, attention is to be paid that the sheathing does not affect the steel.
The sheathing is to be effectively fitted to the deck.
1.4 For ships with a speed v0 > 1,6 [kn], additional strengthening of the strength deck and the sheerstrake may
be required.
1.5 The following definitions apply throughout this Section:
k = material factor according to Section 2, B.2.
pD = load according to Section 4, B.1.
pL = load according to Section 4, C.1.
tK = corrosion addition according to Section 3, K.
2. Connection between strength deck and sheerstrake
2.1 The welded connection between strength deck and sheerstrake may be effected by fillet welds according to
Table 19.3. Where the plate thickness exceeds approximately 25 mm, a double bevel weld connection according to Section
19, B.3.2, shall be provided for instead of fillet welds. Bevelling of the deck stringer to 0,65 times of its thickness in way
of the welded connection is admissible.
In special cases a double bevel weld connection may also be required, where the plate thickness is less than 25 mm.
2.2 Where the connection of deck stringer to sheerstrake is rounded, the requirements of Section 6, C.3.3 are to be
observed.
3. Openings in the strength deck
3.1 All openings in the strength deck are to have well rounded corners circular openings are to be edge-reinforced.
The sectional area of the face bar is not to be less than:
Af = 0,25 @ d @ t [cm2
]
d = diameter of openings[cm]
t = deck thickness [cm].
Thereinforcingfacebarmaybedispensedwith,wherethediameterislessthan300mmandthesmallestdistancefromanother
opening is not less than 5 x diameter of the smaller opening. The distance between the outer edge of openings for pipes etc.
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![A Section 7 - Decks7-2/9
and the ship's side is not to be less than the opening diameter.
3.2 The hatchway corners are to be surrounded by strengthened plates which are to extend over at least one frame
spacing fore-and-aft and athwartships. Within 0,5 L amidships, the thickness of the strengthened plate is to be equal to
thedeckthicknessabreastthehatchwayplusthedeckthicknessbetweenthehatchways.Outside0,5Lamidshipsthethickness
of the strengthened plated need not exceed 1,6 times the thickness of the deck plating abreast the hatchway.
The reinforcement may be dispensed with in case of proof by a fatigue analysis.
3.3 The hatchway corner radius is not to be less than:
r = n @ b (1 – b/B)
rmin = 0,1 m
n =
nmin = 0,1
nmax = 0,25
R = length of hatchway [m]
b = breadth [m], of hatchway or total breadth of hatchways in case of more than one hatchway. b/B need not
be taken smaller than 0,4.
For ships with large hatch openings see 3.6.
3.4 Wherethehatchwaycornersareellipticorparabolic,strengtheningaccordingto3.2isnotrequired.Thedimensions
of the elliptical and parabolical corners shall be as shown in Fig. 7.1:
Fig. 7.1 Elliptic or parabolic hatch corner
Where smaller values are taken for a and c, reinforced insert plates are required which will be considered in each individual
case.
3.5 At the corners of the engine room casings, strengthenings according to 3.2 may also be required, depending on
the position and the dimensions of the casing.
3.6 For ships with large deck openings according to Section 5, F. the design of the hatch corners will be specially
considered on the basis of the stresses due to longitudinal hull girder bending, torsion and transverse loads.
Approximately the following formulae can be used to determine the radii of the hatchway corners:
r $ c1 A c 2
rmin = 0,15 m for hatchway corners in the strength deck
= 0,1 in all other locations
c1 =
for hatchway corners at deck girders alongside the hatchway, adjacent to a closed deck area
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![Section 7 - Decks A 7-3/9
= 0,4 A bQ for hatchway corners at cross deck strips between hatchways adjacent to a closed deck area
=
for hatchway corners adjacent to a cross deck strip
fD = coefficient for deck configuration
= 0,25 +
for hatchway corners of the strength deck and for decks and coamings above the strength deck
= 0,2 +
forthestrengthdeck,decksandcoamingsabovethestrengthdeckandfordeckswithinthedistanceofmaximum
bL below the strength deck, if a further deck with the same hatchway corner radius is arranged in a distance
of less than bL below the strength deck.
= 0,1 for lower decks where the distance from the strength deck exceeds bL
R = relevant length of large deck openings [m] forward and/or aft of the superstructure
Lmin = 100 m
Lmax = 300 m
bL = breadth of deck girder alongside the hatchway [m]
bQ = breadth of cross deck strip between hatchways [m]
ForhatchwaycornersaboveorbelowthestrengthdeckbL andbQ aretobetakenasthebreadthsofthelongitudinalortransverse
structural members adjacent to the hatchway corners.
c2 =
tD = plate thickness of the longitudinal structural member [mm]
ti = thickness of the hatchway corner plate [mm]
1 $ $ 0,625
MT = totallongitudinalbendingmoment[kNm],accordingtoSection5,A.5attheforwardoraftedgeof the relevant
cross deck strip or the relevant closed deck area
Iy = moment of inertia [m4
] of the section according to Section 5, A.5. in the hatchway corner without inserted
strengthened plate
cs = according to Section 5, C.1.1 for the strength deck
= 1,0 for the lower decks
z0 = distance of neutral axis of the hull section from the baseline [m]
zD = distance of the relevant hatchway corner from the baseline[m]
ki = material factor according to Section 2, B. of the relevant hatchway corner
Where required by above calculation or on the basis of direct fatigue assessment hatchway corners are to be surrounded by
strengthened plates, i.e. insert plates, which extend minimum distances a and b from hatch edges (see Fig. 7.2), where
a = [mm]
amin = 350 mm
b = [mm]
Openings in way of hatchway corners are not to be located within the following minimum distances (see Fig. 7.2)
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![A Section 7 - Decks7-4/9
Fig. 7.2 Strengthening of hatchway corners
a) Opening outside of insert plate
c = distance of opening from butt seam
= 2 t + h + 50 [mm] for strength deck
= 2 t + h/2 + 50 [mm] for lower decks
b) Opening inside of insert plate
e = distance of opening from longitudinal bulkhead
= 2 r + h/2 [mm] for strength deck
= 1,5 r + h/2 [mm] for lower decks
h = diameter of opening [mm]
On the basis of direct calculations, other minimum distances for specific cases may be accepted. Outside 0,5 L midships
the thickness of the strengthened plate shall not exceed 1,6 times the thickness of the deck plating abreast the hatchway.
3.7 Stresses due to lateral loads
= [N/mm2
]σ Q
MQ = bending moment around the z-axis due to the action of the external water pressure according to Section 4,
B.2 and/or cargo loads [kNm], stressing the girder consisting of deck strip, longitudinal hatch coaming and
effective parts of longitudinal bulkhead and side shell plating.
W1 = section modulus [m³] of the girder specified above abreast hatchway around the vertical axis. Longitudinal
hatch coamings can only be included, if carried sufficiently beyond the hatchway ends.
Forcontainershipswithhatchwaylengthsnotexceedingapproximately14mandwithtransverseboxgirdersofapproximately
equal rigidity, FQ may be determined by the following formulae:
FQ = [N/mm2
]
p0 = see Section 4, A.2.2
In the hatch corners of ships with large deck openings according to Section 5, F., the following equation must be complied
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![Section 7 - Decks A 7-5/9
with :
Fv = see Section 5, D.1.2.
FL = see Section 5, D.1.
4. Scantlings of strength deck of ships up to 65 m in length
The scantlings of the strength deck for ships, for which proof of longitudinal strength is not required, i.e. in general for ships
withlengthL 65m,thesectionalareaofthestrengthdeckwithin0,4Lamidshipsistobedeterminedsuchthattherequirements
for the minimum midship section modulus according to Section 5, C.2. are complied with.
The thickness within 0,4 L amidship is not to be less than the minimum thickness according to 6.
For the range 0,1 L from ends, the requirement of 7.1 apply.
5. Scantlings of strength deck of ships of more than 65 m in length
5.1 Deck sectional area
The deck sectional area abreast the hatchways, if any, is to be so determined that the section modulii of the cross section
is in accordance with the requirements of Section 5, C.
5.2 Critical plate thickness, buckling strength
5.2.1The critical plate thickness is to be determined according to Section 6, B.2. analogously.
5.2.2Reductions from the critical plate thickness on account of restricted service are not admissible.
5.2.3In regard to buckling strength the requirements of Section 6, B.2.2 apply analogously.
5.3 Deck stringer
If the thickness of the strength deck plating is less than that of the side shell plating, a stringer plate is to be fitted having
the width of the sheerstrake and the thickness of the side shell plating.
6. Minimum thickness
6.1 The thickness of deck plating for 0,4 L amidships outside line of hatchways, is not to be less than the greater of
the two following values:
tmin = (4,5 + 0,05 L) [mm]
or
tE = according to 7.1,
L need not be taken greater than 200 m.
6.2 When the deck is located above a level of T + c0 above basis a smaller thickness than tmin may be accepted if
the stress level permits such reduction. c0 see Section 4, A.2.2.
7. End thickness, thickness inside line of hatchways
7.1 The thickness of strength deck plating for 0,1 L from the ends and between hatchways is not to be less than:
tE1 = [mm]
tE2 = [mm]
tEmin = (5,5 + 0,02 L) [mm]
L need not be taken greater than 200 m.
7.2 Between the midship thickness and the end thickness, the thicknesses are to be tapered gradually.
7.3 The strength of deck structure between hatch openings has to withstand compressive transversely acting loads.
Proof of buckling strength is to be provided according to Section 3, F.
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![B Section 7 - Decks7-6/9
B. Lower Decks
1. Thickness of decks for cargo loads
1.1 The plate thickness is not to be less than:
t = 1,1 a [mm]
tmin = (5,5 + 0,02 L) [mm]
for the 2nd deck
= 6,0 mm for other lower decks
L need not be taken greater than 200 m.
1.2 For the critical deck thickness see A.5.2.
2. Thickness of decks for wheel loading
2.1 The thickness of deck plating for wheel loading is to be determined by the following formulae:
t = [mm]
P = load [kN] of one wheel or group of wheels on a plate panel a @ b 1)
considering the aceleration factor av.
=
Q = axle load [kN]
For fork lift trucks Q is generally to be taken as the total weight of the fork lift truck.
n = number of wheels or group of wheels per axle
av = see Section 4, C.1.1
= 0 for harbour conditions
c = factor according to the following formulae:
for the aspect ratio b/a =1:
for the range 0 < < 0,3 :
c =
for the range 0,3 # 1,0 :
c = 1,20 - 0,40
for the aspect ratio b/a $ 2,5:
for the range 0 < < 0,3 :
c =
for the range 0,3 # 1,0 :
c = 1,20 - 0,517
1)
Where no data available P is to be taken as 25 kN
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![Section 7 - Decks B, C 7-7/9
for intermediate values of b/a the factor c is to be obtained by direct interpolation.
f = print area of wheel or group of wheels
F = area of plate panel a @ b according to Fig. 7.3
a = width of smaller side of plate panel (in general beam spacing)
b = width of larger side of plate panel
F need not be taken greater than 2,5 a2
.
In case of narrowly spaced wheels these may be grouped together to one wheel print area.
Fig. 7.3 Footprint of wheel
2.2 Where the wheel print area is not known, it may approximately be determined as follows:
f = [cm2
]
p = specific wheel pressure according to Table 7.1.
2.3 In deck beams and girders, the stress is not to exceed 165/k [N/mm2
].
Table 7.1 - Specific wheel pressure
Type of vehicle
Specific wheel pressure p [bar]
Pneumatic
tyres
Solid rubber
tyres
private cars 2 -
trucks 8 -
trailers 8 15
fork lift trucks 6 15
3. Machinery decks and accommodation decks
The scantlings of machinery decks and other accommodation decks have to be based on the loads given in Section 4, C.3.
The thickness of the plates is not to be less than:
t = 1,1 @ a @ [mm]
tmin = 5 [mm]
C. Helicopter Decks
1. General
1.1 The starting/landing zone is to be dimensioned for the largest helicopter type expected to use the helicopter deck.
1.2 Forscantlingpurposes,otherloads(cargo,snow/ice,etc.)aretobeconsideredsimultaneouslyorseparately,depending
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![C Section 7 - Decks7-8/9
on the conditions of operation to be expected. Where these conditions are not known, the data contained in 2. may be used
as a basis.
1.3 The following provisions in principle apply to starting/landing zones on special pillar-supported landing decks
or on decks of superstructures and deckhouses.
Note
For the convenience of the users of these Rules reference is made to the "Guide to Helicopter/Ship Operations' published
by the International Chamber of Shipping (ICS).
2. Design Load
The following load cases (LC) are to be considered:
2.1 LC 1
Helicopter lashed on deck, with the following vertical forces acting simultaneously:
.1 Wheel and/or skid force P acting at the points resulting from the lashing position and distribution of the wheels and/or
supports according to helicopter construction.
P = 0,5 @ G (1 + av) [kN]
G = maximum permissible take-off weight [kN]
av = see Section 4, C.1.1
P = evenly distributed force over the contact area f = 30 x 30 cm for single wheel or according to data supplied
by helicopter manufacturers;fordualwheelsorskids to be determined individually in accordance with given
dimensions.
e = wheel or skid distance according to helicopter types to be expected
.2 Force due to weight of helicopter deck Me as follows :
Me (1 + av) [kN]
.3 Load p = 2,0 kN/m2
evenly distributed over the entire landing deck.
2.2 LC 2
Helicopter lashed on deck, with the following horizontal and vertical forces acting simultaneously:
.1 Forces acting horizontally:
H = 0,6 (G + Me) + W [Kn]
W = Wind load, taking into account the lashed helicopter;
wind velocity vw = 50 m/s.
.2 Forces acting vertically:
V = G + Me [kN]
2.3 LC 3
Normal landing impact, with the following forces acting simultaneously:
.1 Wheel and/or skid load P at two points simultaneously, at an arbitrary (most unfavourable) point of the helicopter deck
(landing zone + safety zone)
P = 0,75 G [kN]
.2 Load p = 0,5 kN/m2
evenly distributed
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![Section 8 - Bottom Structures A 8-1/13
Section 8
Bottom Structures
A. Single Bottom
1. Floor plates
1.1 General
1.1.1Floor plates are to be fitted at every frame. For the connection with the frames, see Section 19, B.4.2.
1.1.2Deep floors, particularly in the after peak, are to be provided with buckling stiffeners.
1.1.3The floor plates are to be provided with limbers to permit the water to reach the pump suctions.
1.2 Scantlings
1.2.1Floor plates in the cargo hold area
Onshipswithoutdoublebottomoroutside any double bottomthe scantlings of floor plates fitted betweenafterpeakbulkhead
and collision bulkhead are to be determined according to the following formulae.
The section modulus is not to be less than:
W = c @ T @ e @ R2
[cm3
]
e = spacing of plate floor [m]
R = unsupported span [m], generally measured on upper edge of floor from side shell to side shell.
Rmin = 0,7 B, if the floors are not supported at longitudinal bulkheads
c = 7,5 for spaces which may be empty at full draught, e.g. machinery spaces, storerooms, etc.
= 4,5 elsewhere.
The depth of the floor plates is not to be less than :
h = 55 @ B – 45 [mm]
hmin = 180 mm.
In ships having rise of floor, at 0,1 R from the ends of the length R where possible, the depth of the floor plate webs shall not
be less than half the required depth.
In ships having a considerable rise of floor, the depth of the floor plate webs at the beginning of the turn of bilge is not to
be less than the depth of the frame.
The web thickness is not to be less than :
t = [mm]
The web sectional area is to be determined according to B.6.2.2 analogously.
1.2.2The face plates of the floor plates are to be continuous over the span R. If they are interrupted at the centre keelson, they
are to be connected to the centre keelson by means of full penetration welding.
1.2.3 Floor plates in the peaks
.1 The thickness of the floor plates in the peaks is not to be less than:
t = 0,035 L + 5,0 [mm].
The thickness, however, need not be greater than required by B.6.2.1.
.2 The floor plate height in the fore peak above top of keel or stem shoe is not to be less than :
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![A, B Section 8 - Bottom Structures8-2/13
h = 0,06 H + 0,7 [m].
For small ship deviation from this requirement may be considered.
.3 The floor plates in the after peak are to extend over the stern tube (see also Section 13, C.1.4).
.4 Wherepropellerrevolutionsareexceeding300rpm(approx.)thepeakfloorsabovethepropelleraretobe strengthened..
Particularly in case of flat bottoms additional longitudinal stiffeners are to be fitted above or forward of the propeller.
2. Longitudinal girders
2.1 General
2.1.1 All single bottom ships are to have a centre girder. Where the breadth measured on top of floors does not exceed
9 mone additional side girder is to be fitted, and two side girders where the breadth exceeds 9 m. Side girders are not required
where the breadth does not exceed 6 m.
2.1.2For the spacing of side girders from each other and from the centre girder in way of bottom strengthening forward see
Section 6, E.1.
2.1.3The centre and side girders are to extend as far forward and aft as practicable. They are to be connected to the girders
of a non-continuous double bottom or are to be scarphed into the double bottom by two frame spacings.
2.2 Scantlings
2.2.1Centre girder
The web thickness tw and the sectional area of the face plate Af within 0,7 L amidships is not to be less than:
tw = 0,07 L + 5,5 [mm].
Af = 0,7 L + 12 [cm2
].
Towards theendsthethicknessofthewebplateaswellasthesectionalarea ofthetopplatemaybereducedby10%.Lightening
holes are to be avoided.
2.2.2 Side girder
The web thickness tw and the sectional area of the face plate Af within 0,7 L amidships is not to be less than:
tw = 0,04 L + 5 [mm].
Af = 0,2 L + 6 [cm2
].
Towards the ends, the thickness of the web plate and the sectional area of the face plate may be reduced by 10%.
B. Double Bottom
1. General
1.1 On passenger ships and cargo ships other than tankers a double bottom shall be fitted extending from the collision
bulkhead to the afterpeak bulkhead, as far as this is practicable and compatible with the design and proper working of the
ship. For oil tankers see Section 24.
1.2 The arrangement shall comply with Chapter II-1 of SOLAS as amended. See also Section 36, C.
1.3 Where a double bottom is required to be fitted the inner bottom shall be continued out to the ship's sides in such
a manner as to protect the bottom to the turn of the bilge. Such protection will be deemed satisfactory if the inner bottom
is not lower at any part than a plane parallel with the keel line and which is located not less than a vertical distance h measured
from the keel line, as calculated by the formula :
h =
However, in no case is the value of h to be less than 760 mm, and need not be taken as more than 2000 mm.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-142-320.jpg)
![Section 8 - Bottom Structures B 8-3/13
1.4 Small wells for hold drainage may be arranged in the double bottom, their depth, however, shall be as small as
practicable. A well extending to the outer bottom, may, however, be permitted at the after end of the shaft tunnel. Other
wells may be permitted if their arrangement does not reduce the level of protection equivalent to that afforded by a double
bottomcomplying with this Section. In no case shall the vertical distance fromthe bottomof such a well to a plane coinciding
with the keel line be less than 500 mm.
1.5 In fore- and after peak a double bottom need not be arranged.
1.6 The centre girder should be watertight at least for 0,5 L amidships, unless the double bottom is subdivided by
watertight side girders. On ships which are assigned the load line permissible for timber deck load, the double bottom is to
be subdivided watertight by the centre girder or side girders as required by the ICLL 66.
1.7 For the double bottom structures of bulk carriers, see Section 23, B.4.
1.8 For bottom strengthening forward see Section 6,E.
1.9 For the material factor k see Section 2, B.2. For the corrosion addition tK see Section 3, K.
1.10 For buckling strength of the double bottom structures see 8.3.
1.11 Ships touching ground whilst loading and discharging
On request of the owner, the bottom structures of a ship which is expected to frequently touch ground whilst loading and
discharging will be examined particularly.
To fulfil this requirement, where the transverse framing system is adopted, plate floors are to be fitted at every frame and
the spacing of the side girders is to be reduced to half the spacing as required according to 3.1.
When the longitudinal framing system is adopted, the longitudinal girder system according to 7.5 is to be applied.
The thickness of bottom plating is to be increased by 10 %, compared to the plate thickness according to Section 6,
B.1. to B.5.
2. Centre girder
2.1 Lightening holes
Lightening holes in the centre girder are generally permitted only outside 0,75 L amidships. Their depth is not to exceed
half the depth of the centre girder and their lengths are not to exceed half the frame spacing.
2.2 Scantlings
2.2.1 The depth of the centre girder is not to be less than:
h = 350 + 45 @ B [mm]
hmin = 600 mm
Where longitudinal wing bulkheads are fitted, the distance between the bulkheads may be inserted in lieu of B, however,
not less than 0,8 B.
For double bottoms with wing tanks (e.g. on bulk carriers) instead of the breadth B the fictitious breadth B' according to
Fig. 8.1 may be used, but not less than 0,8 . B.
B' = (2 B + b) for " $ 35°
B' = B for " < 35°
Fig. 8.1 - Fictitious breadth B’
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-143-320.jpg)
![B Section 8 - Bottom Structures8-4/13
2.2.2 The thickness of the centre girder is not to be less than:
– within 0,7 L amidships :
tm = [mm] for h # 1200 [mm]
tm = [mm] for h > 1200 [mm]
– 0,15 L at the ends:
te = 0,9 A tm
ha = depth of centre girder as built [mm]
ha need not be taken less than h to calculate tm
tm = shall not be less than t according to 7.5
3. Side girders
3.1 Arrangement
At least one side girder shall be fitted in the engine room and in way of 0,25 L aft of F.P. In the other parts of the double
bottom, one side girder shall be fitted where the horizontal distance between ship's side and centre girder exceeds 4,5 m.
Two side girders shall be fitted where the distance exceeds 8 m, and three side girders where it exceeds 10,5 m. The distance
of the side girders from each other and from centre girder and ship's side respectively shall not be greater than:
1,8 m in the engine room within the breadth of engine seatings,
4,5 m where one side girder is fitted in the other parts of double bottom,
4,0 m where two side girders are fitted in the other parts of double bottom,
3,5 m where three side girders are fitted in the other parts of double bottom.
3.2 Scantlings
The thickness of the side girders is not to be less than :
t = [mm]
h = depth of the centre girder [mm] according to 2.2.
ha = as built depth of side girders [mm]
ha need not be taken less than h to calculate t
t = shall not be less than t according to 7.5.
For strengthenings under the engine seating, see C.2.3.
4. Inner bottom
4.1 The thickness of the inner bottom plating is not to be less than :
t = [mm]
p = design pressure [kN/m2
]
p is the greater of the following values:
p1 = 10 (T - hDB)
p2 = 10 @ h, where the inner bottom forms a tank boundary
p3 = pi according to Section 4, C.2.
h = distance from top of overflow pipe to inner bottom [m]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-144-320.jpg)
![Section 8 - Bottom Structures B 8-5/13
hDB = double bottom height [m].
4.2 If no ceiling according to Section 21, B.1. is fitted on the inner bottom, the thickness determined in accordance
with 4.1 for p1 or p2 is to be increased by 2 mm. This increase is not required for ships with the Notation "CONTAINER
SHIP".
4.3 For strengthening in the range of grabs, see Section 23, B.4.3.
4.4 For strengthening of inner bottom in machinery spaces, see C.2.4.
5. Double bottom tanks
5.1 Scantlings
Structures forming boundaries of double bottom tanks are to comply with the requirements of Section 12.
5.2 Fuel and lubricating oil tanks
5.2.1 In double bottom tanks, oil fuel may be carried, the flash point (closed cup test) of which exceeds 60E C.
5.2.2 Where practicable, lubricating oil discharge tanks or circulating tanks shall be separated from the shell.
5.2.3 For the separation of oil fuel tanks from tanks for other liquids, see Section 12, A.5.
5.2.4 For air, overflow and sounding pipes, see Section 21, E. as well as Rules for Machinery Installations, Volume
III, Section 11.
5.2.5 Manholes for access to oil fuel double bottom tanks situated under cargo oil tanks are not permitted in cargo oil
tanks nor in the engine room (see also Section 24, A.12.4).
5.2.6 The thickness of structures is not to be less than the minimum thickness according to Section 12, A.7.
5.2.7If the tank top of the lubricating oil circulating tank is not arranged at the same level as the adjacent inner bottom, this
discontinuity of the flow of forces has to be compensated by vertical and/or horizontal brackets.
The brackets shall be designed with a soft taper at the end of each arm. The thickness of the vertical brackets shall correspond
to the thickness of the floor plates according to C.2.2, the thickness of the horizontal brackets shall correspond to the tank
top thickness of the circulating tank.
The brackets shall be connected to the ship structure by double-bevel welds according to Section 19, B.3.2.2.
5.3 Bilge wells
Bilge wells shall have a capacity of more than 0,2 m3
. Small holds may have smaller bilge wells. For the use of manhole
covers or hinged covers for the access to the bilge suctions, see Rules for Machinery Installations, Volume III, Section
11. Bilge wells are to be separated from the shell. Section 29, F.5. shall be applied analogously.
5.4 Sea chests
5.4.1 The plate thickness of sea chests is not to be less than :
t = [mm]
a = spacing of stiffeners [m]
p = blow out pressure at the safety valve [bar]. p is not to be less than 2 bar (see also Rules for Machinery
Installations, Volume III, Section 11)
5.4.2 The section modulus of sea chest stiffeners is not to be less than:
W = 56 @ a @ p @ R2
@ k [cm3
]
a and p see 5.4.1
R = unsupported span of stiffeners[m].
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-145-320.jpg)
![B Section 8 - Bottom Structures8-6/13
5.4.3The sea-water inlet openings in the shell are to be protected by gratings.
5.4.4A cathodic corrosion protection with galvanic anodes made of zinc or aluminium is to be provided in sea chests with
chest coolers. For the suitably coated plates a current density of 30 :A/m2
is to be provided and for the cooling area a current
density of 180 :A/m2
.
6. Double bottom, transverse framing system
6.1 Plate floors
6.1.1 It is recommended to fit plate floors at every frame in the double bottom if transverse framing is adopted.
6.1.2Plate floors are to be fitted at every frame:
.1 in way of strengthening of the bottom forward according to Section 6, E.,
.2 in the engine room,
.3 under boiler seatings.
6.1.3 Plate floors are to be fitted:
.1 below bulkheads
.2 under corrugated bulkheads, see also Section 3, D.4. and Section 23, B.4.3.
6.1.4 For the remaining part of the double bottom, the spacing of plate floors shall not exceed approximately 3 m.
6.2 Scantlings
6.2.1 The thickness of plate floors is not to be less than :
tpf = [mm]
tm = thickness of centre girder according to 2.2.2.
The thickness need not exceed 16,0 mm.
6.2.2The web sectional area of the plate floors is not to be less than :
Aw = g @ T @ R @ e (1 – ) k [cm2
]
e = spacing of plate floors [m]
R = span between longitudinal bulkheads, if any, [m]
= B, if longitudinal bulkheads are not fitted
y = distance between supporting point of the plate floor (ship's side, longitudinal bulkhead) and the section
considered [m]. The distance y is not to be taken greater than 0,4 R.
g = 0,5 for spaces which may be empty at full draught, e.g. machinery spaces, store rooms, etc.
= 0,3 elsewhere.
6.2.3Where in small ships side girders are not required (see 3.1) at least one vertical stiffener is to be fitted at every plate
floor; its thickness is to be equal to that of the floors and its depth of web at least 1/15 of the height of centre girder.
6.2.4In way of strengthening of bottom forward according to Section 6, E., the plate floors are to be connected to the shell
plating and inner bottom by continuous fillet welding.
6.2.5For strengthening of floors in machinery spaces, see C.2.2.
6.3 Watertight floors
6.3.1The thickness of watertight floors is not to be less than that required for tank bulkheads according to Section 12,
B.2. In no case their thickness is to be less than required for plate floors according to 6.2.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-146-320.jpg)
![Section 8 - Bottom Structures B 8-7/13
6.3.2The scantlings of stiffeners at watertight floors are to be determined according to Section 12, B.3.
6.4 Bracket floors
6.4.1Where plate floors are not required according to 6.1 bracket floors may be fitted.
6.4.2Bracket floors consist of bottom frames at the shell plating and reversed frames at the inner bottom, attached to centre
girder, side girders and ship's side by means of brackets.
6.4.3The section modulus of bottom and inner bottom frames is not to be less than:
W = n @ c @ a @ R2
@ p @ k [cm3
]
p = design load, as applicable [kN/m2
] as follows :
for bottom frames
p = pB according to Section 4, B.3.
for inner bottom frames
p = pi according to Section 4, C.2.
= p1 or p2 according to Section 4, D.1.
= 10 (T - hDB)
The greater value is to be used.
hDB = double bottom height [m]
n = 0,44, if p = p2
= 0,55, if p = pi or p1
= 0,70, if p = pB
c = 0,60 where struts according to 6.6 are provided at R/2, otherwise c = 1,0
R = unsupported span [m] disregarding struts, if any.
6.5 Brackets
6.5.1The brackets are, in general, to be of same thickness as the plate floors. Their breadth is to be 0,75 of the depth of the
centregirderasper2.2.Thebracketsaretobeflangedattheirfreeedges,wheretheunsupportedspanofbottomframesexceeds
1 m or where the depth of floors exceeds 750 mm.
6.5.2At the side girders, bottom frames and inner bottom frames are to be supported by flat bars having the same depth as
the inner bottom frames.
6.6 Struts
The cross sectional area of the struts is to be determined according to Section 10, C.2. analogously. The design force is to
be taken as the following value:
P = 0,5 @ p @ a @ R [kN]
p = load according to 6.4.3
R = unsupported span according to 6.4.3
7. Double bottom, longitudinal framing system
7.1 General
Wherethelongitudinalframingsystemchanges to the transverse framing system, structural continuity or sufficientscarphing
is to be provided for.
7.2 Bottom and inner bottom longitudinals
7.2.1The section moduli are to be calculated according to Section 9, B.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-147-320.jpg)
![B Section 8 - Bottom Structures8-8/13
7.2.2Where bottomandinnerbottomlongitudinals are coupledby struts in the centre of their unsupported spanR their section
modulimaybereducedto60%ofthevaluesrequiredbySection9B.Thescantlingsofthestrutsarebedeterminedinaccordance
with 6.6.
7.3 Plate floors
7.3.1The floor spacing shall, in general, not exceed 5 times the mean longitudinal frame spacing.
7.3.2 Floors are to be fitted at every frame as defined in 6.1.3 as well as in the machinery space under the main engine.
In the remaining part of the machinery space, floors are to be fitted at every alternate frame.
7.3.3Regarding floors in way of the strengthening of the bottom forward, Section 6, E. is to be observed. For ships intended
for carrying heavy cargo, see Section 23.
7.3.4The scantlings of floors are to be determined according to 6.2.
7.3.5The plate floors are to be stiffened at every longitudinal by a vertical stiffener having the same scantlings as the inner
bottom longitudinals. The depth of the stiffener need not exceed 150 mm. If necessary a strength check can be required.
7.4 Brackets
7.4.1Where the ship's sides are framed transversely flanged brackets having a thickness of the floors are to be fitted between
the plate floors at every transverse frame, extending to the outer longitudinals at the bottom and inner bottom.
7.4.2One bracket is to be fitted at each side of the centre girder between the plate floors where the plate floors are spaced
not more than 2,5 m apart. Where the floor spacing is greater, two brackets are should be fitted.
7.5 Longitudinal girder system
7.5.1Wherelongitudinalgirdersare fittedinstead of bottomlongitudinals, the spacing offloorsmaybegreaterthanpermitted
by 7.3.1, provided that adequate strength of the structure is proved.
7.5.2The plate thickness of the longitudinal girders is not to be less than:
t = (5,0 + 0,03 L) [mm]
tmin = 6,0 [mm]
7.5.3The longitudinal girders are to be examined for sufficient safety against buckling according to Section 3,F.
8. Direct calculation of bottom structures
8.1 General, Definitions
8.1.1 Where deemed necessary, a direct calculation of bottomstructures according to Section 23, B.4. may be required.
Where it is intended to load the cargo holds unevenly (alternately loaded holds), this direct calculation is to be carried out.
Definitions
pi = load on inner bottom according to Section 4, C.2. [kN/m²] or Section 4, C.1.3 [kN], (where applicable)
Where high density ore cargo is intended to be carried in the holds in a conical shape, in agreement with
BKI a corresponding load distribution pi on the inner bottom is to be used for the calculation.
= 10 T + p0 @ cF [kN/m²] (hogging condition)
= 10 T – p0 @ cF [kN/m²] (sagging condition)
p0 , cF see Section 4, A.2.2
FL = designhullgirderbendingstress[N/mm²]accordingtoSection5,D.1.(hoggingorsagging,whichever condition
is examined).
FR = bending stress [N/mm²] in longitudinal direction, due to the load p, in longitudinal girders
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-148-320.jpg)
![Section 8 - Bottom Structures B 8-9/13
Fq = bending stress [N/mm²] in transverse direction, due to the load p, in transverse girders
J = shear stress in the longitudinal girders or transverse girders due to the load p [N/mm²].
8.1.2 For two or more holds arranged one behind the other, the calculation is to be carried out for the hogging as well
as for the sagging condition.
8.2 Design loads, permissible stresses
8.2.1Design loads
p = [kN/m2
] for loaded holds.
= [kN/m2
] for empty holds.
Where the grillage system of the double bottom is subjected to single loads caused by containers, the stresses in the bottom
structure are to be calculated for these single loads as well as for the bottom load p’a as per 8.1.1. The permissible stresses
specified there in are to be observed.
8.2.2 Permissible stresses
.1 Permissible equivalent stress Fv
The equivalent stress is not to exceed the following value :
Fv = [N/mm2
]
=
Fx = stress in the ship’s longitudinal direction
= FL + FR
= 0 for webs of transverse girders
Fy = stress in the ship’s transverse direction
= Fq
= 0 for webs of longitudinal girders
Note
Where grillage computer programs are used the following stress definitions apply :
Fx =
Fy =
.2 Permissible max. values for FR, Fq and J
The stresses FR, Fq and J alone are not to exceed the following values:
FR, Fq = [N/mm2
]
J = [N/mm2
]
8.3 Buckling strength
The buckling strength of the double bottomstructures is to be examined according to Section 3, F. For this purpose the design
stresses according to Section 5, D.1. and the stresses due to local loads are to be considered.
9. Testing for tightness
Each compartment or tank of a double bottom is to be tested for tightness as specified in Section 12, H.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-149-320.jpg)
![C Section 8 - Bottom Structures8-10/13
C. Bottom Structure in Machinery Spaces in Way of the Main Propulsion Plant
1. Single bottom
1.1 The scantlings of floors are to be determined according to A.1.2.1 for the greatest span measured in the engine
room.
1.2 The web depth of the plate floors in way of the engine foundation should be as large as possible. The depth of
plate floors connected to web frames shall be similar to the depth of the longitudinal foundation girders. In way of the crank
case, the depth shall not be less than 0,5 h.
The web thickness is not to be less than:
t = [mm]
h see A.1.2.1.
1.3 The thickness of the longitudinal foundation girders is to be determined according to 3.2.1.
1.4 No centre girder need be fitted in way of longitudinal foundation girders. Intercostal docking profiles are to be
fitted instead. The sectional area of the docking profiles is not to be less than:
Aw = 10 + 0,2 L [cm2
].
Docking profiles are not required where a bar keel is fitted. Brackets connecting the plate floors to the bar keel are to be fitted
on either side of the floors.
2. Double bottom
2.1 General
2.1.1Lighteningholesinwayoftheenginefoundationaretobekeptassmallaspossiblewithdueregard,however,toaccessibility.
Where necessary, the edges of lightening holes are to be strengthened by means of face bars or the plate panels are to be
stiffened.
2.1.2Local strengthenings are to be provided beside the following minimum requirements, according to the construction
and the local conditions.
2.2 Plate floors
Plate floors are to be fitted at every frame. The floor thickness according to B.6.2 is to be increased as follows :
minimum 5%, maximum 15%.
P = single engine output [kW].
The thickness of the plate floors below web frames is to be increased in addition to the above provisions. In this case the
thickness of the plate floors is not to be taken less than the web thickness according to Section 9, A.6.2.1.
2.3 Side girders
2.3.1The thickness of side girders under an engine foundation top plate inserted into the inner bottom is to be similar to the
thickness of side girders above the inner bottom according to 3.2.1.
2.3.2Side girders with the thickness of longitudinal girders according to 3.2 are to be fitted under the foundation girders in
full height of the double bottom. Where two side girders are fitted on either side of the engine, one may be a half-height girder
under the inner bottom for engines up to 3000 kW.
2.3.3Side girders under foundation girders are to be extended into the adjacent spaces and to be connected to the bottom
structure. This extension abaft and forward of the engine room bulkheads shall be two to four frame spacings if practicable.
2.3.4No centre girder is required in way of the engine seating (see 1.4).
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-150-320.jpg)
![Section 8 - Bottom Structures C 8-11/13
2.4 Inner bottom
Between the foundation girders, the thickness of the inner bottom plating required according to B.4.1 is to be increased by
2 mm. The strengthened plate is to be extended beyond the engine seating by three to five frame spacings.
3. Engine seating
3.1 General
3.1.1The following rules apply to low speed engines. Seating for medium and high speed engines as well as for turbines
will be specially considered.
3.1.2The rigidity of the engine seating and the surrounding bottom structure must be adequate to keep the deformations of
the systemdue to the loads within the permissible limits. In special cases, proofof deformations and stresses may be required.
Note :
1. At the draught resulting in the maximum deflection in way of the foundation the deflection of two stroke, cross head
engines including foundation ought to be less than 1 mm over the length of the engine. In addition to the deflection of engine
and foundation the crank web deflections by which the admissible engine deflection may be limited to values less than 1 mm
have to be considered as well. For medium speed and high speed engines not only the deflections of crank webs have to be
taken into account but for assuring trouble free bearing conditions of the crank shaft the bending deflection of the engine
is to be limited.
2. If in special cases a direct calculation of motorseatings may become necessary, the following is to be observed:
– For seatings of slow speed two-stroke diesel engines and elastically mounted medium speed four-stroke diesel
engines the total deformation ªf = fu + fo shall not be greater than:
Îf = 0,2 A RM [mm]
RM = length of motor [m]
fu = maximum vertical deformation of the seating downwards within the length RM [mm]
fo = maximum vertical deformation of the seating upwards within the length RM [mm].
The individual deformations fu and fo shall not be greater than:.
fu max , fo max = 0,7 × Îf [mm]
Forthecalculationofthedeformationsthemaximumstaticandwaveinduceddynamicinternalandexternaldifferential
loads due to local loads and the longitudinal hull girder bending moments as well as the rigidity of the motor are
to be considered.
– For seatings of non-elastically mounted medium speed four-stroke diesel engines the deformation values shall
not exceed 50% of the above values.
3.1.3Dueregardistobepaid,attheinitialdesignstage,toagoodtransmissionofforcesintransverseandlongitudinaldirection,
see also B.5.2.7.
3.1.4Thefoundationboltsforfasteningtheengineattheseatingshallbespacednomore than 3 x d apart fromthe longitudinal
foundation girder. Where the distance of the foundation bolts from the longitudinal foundation girder is greater, proof of
equivalence is to be provided.
d = diameter of the foundation bolts.
3.1.5In the whole speed range of main propulsion installations forcontinuousserviceresonancevibrationswithinadmissible
vibrationamplitudesmustnotoccur;ifnecessarystructuralvariationshavetobeprovidedforavoidingresonancefrequencies.
Otherwise, a barred speed range has to be fixed. Within a range of -10% to + 5% related to the rated speed no barred speed
range is permitted. BKI may require a vibration analysis and, if deemed necessary, vibration measurement.
3.2 Longitudinal girders
3.2.1The thickness of the longitudinal girders above the inner bottom is not to be less than:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-151-320.jpg)
![C, D Section 8 - Bottom Structures8-12/13
t = [mm] for P < 1500 kW
t = [mm] for 1500 P < 7500 kW
t = [mm] for P 7500 kW
P see 2.2.
3.2.2Where two longitudinal girders are fitted on either side of the engine, their thickness required according to 3.2.1 may
be reduced by 4 mm.
3.2.3The sizes of the top plate (width and thickness) shall be sufficient to attain efficient attachment and seating of the engine
and -depending on seating height and type of engine- adequate transverse rigidity.
The thickness of the top plate shall approximately be equal to the diameter of the fitted-in bolts. The cross sectional area
of the top plate is not to be less than:
AT = [cm2
] for P 750 kW
= [cm2
] for P > 750 kW
Where twin engines are fitted, a continuous top plate is to be arranged in general if the engines are coupled to one propeller
shaft.
3.2.4Thelongitudinalgirdersoftheengineseatingaretobesupportedtransverselybymeansofwebframesorwingbulkheads.
The scantlings of web frames are to be determined according to Section 9, A.6.
3.2.5Top plates are preferably to be connected to longitudinal and transverse girders thicker than approx. 15 mm by means
of a double bevel butt joint (K butt joint), (see also Section 19, B.3.2).
D. Docking Calculation
For ships exceeding 120 m in length, for ships of special design, particularly in the aft body and for ships with a docking
load of more than 700 kN/m a special calculation of the docking forces is required. The maximum permissible cargo load
toremainonboardduringdockingandtheloaddistributionaretobespecified.Theproofofsufficientstrengthcanbeperformed
either by a simplified docking calculation or by a direct docking calculation. The number and arrangement of the keel blocks
shall agree with the submitted docking plan. Direct calculations are required for ships with unusual overhangs at the ends
or with inhomogeneous distribution of cargo.
1. Simplified docking calculation
The local forces of the keel blocks acting on the bottomstructures can be calculated in a simplified manner using the nominal
keel block load q0. Based on these forces sufficient strength must be shown for all structural bottom elements which may
be influenced by the keel block forces.
The nominal keel block load q0 is calculated as follows, see also Figure 8.2:
q0 = [kN/m]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-152-320.jpg)
![Section 8 - Bottom Structures D 8-13/13
Fig. 8.2 - Load on keel block
where
GS = total ship weight during docking including cargo, ballast and consumables [kN]
LKB = length of the keel block range [m]; i.e. in general the length of the horizontal flat keel
C = weighting factor
= 1,25 in general
= 2,0 in the following areas:
– within 0,075 @ LKB from both ends of the length LKB
– below the main engine
– in way of the transverse bulkheads along a distance of 2 @ e
– in way of gas tank supports of gas tankers
e = distance of plate floors adjacent to the transverse bulkheads [m]; for e no value larger than 1 m needs to be
taken.
If a longitudinal framing system is used in the double bottom in combination with a centre line girder in accordance with
B.2., it may be assumed that the centre line girder carries 50 % of the force and the two adjacent (see Section 6, B.5.2) keel
block longitudinals 25 % each.
2. Direct docking calculation
If the docking block forces are determined by direct calculation, e.g. by a finite element calculation, considering the stiffness
of the ship's body and the weight distribution, the ship has tobe assumed as elastically bedded at the keel blocks. The stiffness
of the keel blocks has to be determined including the wood layers.
If a floating dock is used, the stiffness of the floating dock is to be taken into consideration.
Transitory docking conditions need also to be considered.
3. Permissible stresses
The permissible equivalent stress Fv is:
Fv = [N/mm2
]
4. Buckling strength
The bottomstructures are to be examined according to Section 3,F. For this purpose a safety factor S = 1,05 has to be applied.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-153-320.jpg)
![Section 9 - Framing System A 9-1/12
Section 9
Framing System
A. Transverse Framing
1. General
1.1 Frame spacing
Forward of the collision bulkhead and aft of the after peak bulkhead, the frame spacing shall in general not exceed 600 mm.
1.2 Definitions
k = material factor according to Section 2, B.2.
R = unsupported span [m] according to Section 3, C., see also Fig. 9.1
Rmin = 2,0 m
RKu, RKo = length of lower/upper bracket connection of main frames within the length R [m], see Fig. 9.1
Fig. 9.1 - Unsupported span of transverse frames
ma =
e = spacing of web frames [m]
p = ps or pe as the case may be
ps = load on ship's sides [kN/m2
] according to Section 4, B.2.1
pe = load on bow structures [kN/m2
] according to Section 4, B.2.2 or stern structures according to Section
4, B.2.3 as the case may be
pL = 'tween deck load [kN/m2
] according to Section.4, C.1.
p1, p2 = pressure [kN/m2
] according to Section 4, D.1.
Hu = depth up to the lowest deck [m]
cr = factor for curved frames
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-155-320.jpg)
![A Section 9 - Framing System9-2/12
=
crmin = 0,75
s = max. height of curve.
2. Main frames
2.1 Scantlings
2.1.1The section modulus WR and shear area AR of the main frames including end attachments are not to be less than:
WR = [cm3
]
upper end shear area :
ARO = [cm2]
lower end shear area :
ARU = [cm2]
n = 0,9 ! 0,0035 @ L for L < 100 m
= 0,55 for L 100 m
c =
cmin = 0,6
Within the lower bracket connection the section modulus is not to be less than the value obtained for c = 1,0.
2.1.2In ships with more than 3 decks the main frames are to extend at least to the deck above the lowest deck.
2.1.3The scantlings of the main frames are not to be less than those of the 'tween deck frames above.
2.1.4Where the scantlings of the main frames are determined by strength calculations, the following permissible stresses
are to be observed:
bending stress: Fb = [N/mm2
]
shear stress: J = [N/mm2
]
equivalent stress: Fv = [N/mm2
]
2.1.5Forces due to lashing arrangements acting on frames are tobe considered when determining the scantlings of the frames
(see also Section 21, H)
2.1.6For main frames in holds of bulk carriers see also Section 23, B.5.2.
2.2 Frames in tanks
The section modulus W and shear area A of frames in tanks or in hold spaces for ballast water are not to be less than the
greater of the following values :
W1 = n @ c @ a @ R2
@ p1 @ cr @ k [cm3
]
W2 according to Section 12, B.3.1, and
A1 = (1 - 0,817 @ ma) 0,05 @ a @ R @ p1 @ k [cm2
]
A2 = (1 - 0,817 @ ma) 0,04 @ a @ R @ p2 @ k [cm2
]
n and c see 2.1.1.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-156-320.jpg)
![Section 9 - Framing System A 9-3/12
2.3 End attachment
2.3.1The lower bracket attachment to the bottom structure is to be determined according to Section 3, D.2. on the basis of
the main frame section modulus.
2.3.2The upper bracket attachment to the deck structure and/or to the 'tween deck frames is to be determined according to
Section 3, D .2. on the basis of the section modulus of the deck beams or 'tween deck frames whichever is the greater.
2.3.3Where frames are supported by a longitudinally framed deck, the frames fitted between web frames are to be connected
to the adjacent longitudinals by brackets. The scantlings of the brackets are to be determined in accordance with Section
3, D.2. on the basis of the section modulus of the frames.
3. 'Tween deck and superstructure frames
3.1 General
In ships having a speed exceeding v0 = 1,6 [kn], the forecastle frames forward of 0,1 L from F.P are to have at least
the same scantlings as the frames located between the first and the second deck.
Where further superstructures, or big deckhouses are arrangedonthe superstructures strengthening of the frames of the space
below may be required.
For 'tween deck frames in tanks, the requirements for the section moduli W1 and W2 according to 2.2 are to be observed.
3.2 Scantlings
The section modulus Wt and shear area At of the ’tween deck and superstructure frames are not to be less than:
Wt = 0,55 @ a @ R2
@ p @ cr @ k [cm3
]
At = (1 - 0,817 @ ma) 0,05 @ a @ R @ p @ k [cm2
]
p is not to be taken less than:
pmin = 0,4 @ pL @ [kN/m2
]
b = unsupported span of the deck beam below the respective 'tween deck frame [m].
For 'tween deck frames connected at their lower ends to the deck transverses, pmin, is to be multiplied by the factor :
f1 = 0,75 + 0,2 1,0
3.3 End attachment
'Tween deck and superstructure frames are to be connected to the main frames below, or to the deck. The end attachment
may be carried out in accordance with Fig. 9.2.
For 'tween deck and superstructure frames 2.3.3 is to be observed, where applicable.
Fig 9.2 - Typical ends attachments of tween deck and superstructure frames
4. Peak frames and frames in way of the stern
4.1 Peak frames
4.1.1 Section modulus WP and shear area AP of the peak frames are not to be less than:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-157-320.jpg)
![A Section 9 - Framing System9-4/12
WP = 0,55 @ a @ R2
@ p @ cr @ k [cm3
]
AP = (1 - 0,817 @ ma) 0,05 @ a A R @ p @ k [cm2
]
4.1.2Where the length of the forepeak does not exceed 0,06 L the section modulus required at half forepeak length may be
maintained throughout the entire forepeak.
4.1.3The peak frames are to be connected to the stringer plates to ensure sufficient transmission of shear forces.
4.1.4Ships not exceeding 30 m in length are to have peak frames having the same section modulus as the main frames.
4.1.5Where peaks are to be used as tanks, the section modulus of the peak frames is not to be less than required by Section
12, B.3.1 for W2.
4.2 Frames in way of the stern
4.2.1The frames in way of the cruiser stern arranged at changing angles to the transverse direction are to have a spacing not
exceeding 600 mm and are to extend up to the deck above peak tank top maintaining the scantlings of the peak frames.
4.2.2An additional stringer may be required in the after ship outside the afterpeak where frames are inclined considerably
and not fitted vertically to the shell.
5. Strengthenings in fore- and aft body
5.1 General
In the fore body, i.e. from the forward end to 0,15 L behind F.P., flanged brackets have to be used in principle.
As far as practicable and possible, tiers of beams or web frames and stringers are to be fitted in the fore- and after peak.
5.2 Tiers of beams
5.2.1Forward of the collision bulkhead, tiers of beams (beams at every other frame) generally spaced not more than 2,6 m
apart, measured vertically, are to be arranged below the lowest deck within the forepeak. Stringer plates are to be fitted on
the tiers of beams which are to be connected by continuous welding to the shell plating and by a bracket to each frame. The
scantlings of the stringer plates are to be determined from the following formulae:
width b = 75 [mm]
thickness t = 6,0 + [mm].
5.2.2The cross sectional area of each beam is to be determined according to Section 10, C.2 for a load
P = A @ p [kN]
A = load area of a beam [m2
]
p = ps or pe, whichever is applicable.
5.2.3In the after peak, tiers of beams with stringer plates generallyspaced 2,6 mapart,measuredvertically, are to be arranged
as required under 5.2.1, as far as practicable with regard to the ship's shape.
5.2.4Intermittent welding at the stringers in the afterpeakistobeavoided.Anyscallopingattheshellplatingistoberestricted
to holes required for welding and for limbers.
5.2.5Where peaks are used as tanks, stringer plates are to be flanged or face bars are to be fitted at their inner edges. Stringers
are to be effectively fitted to the collision bulkhead so that the forces can be properly transmitted.
5.2.6 Whereperforateddecksarefittedinsteadoftiersofbeams,theirscantlingsaretobedeterminedasforwashbulkheads
according to Section 12, G. The requirements regarding cross sectional area stipulated in 5.2.2 are, however, to be complied
with.
5.3 Web frames and stringers
5.3.1Where web frames and supporting stringers are fitted instead of tiers of beams, their scantlings are to be determined
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-158-320.jpg)
![Section 9 - Framing System A 9-5/12
as follows:
.1 Section modulus:
W = 0,55 @ e @ R2
@ ps @ nc @ k [cm3
]
.2 Web sectional area at the supports:
Aw = 0,05 @ e @ R1 @ ps @ k [cm2
]
R = unsupported span [m], without consideration of cross ties, if any
R1 = similar to R, however, considering cross ties, if any
nc = coefficient according to the following Table 9.1.
5.3.2Vertical transverses are to be interconnected by cross ties the cross sectionalareaofwhichistobedeterminedaccording
to 5.2.2.
5.3.3 Where web frames and stringers in the fore body are dimensioned by strength calculations the stresses shall not
exceed the permissible stresses in 2.1.4.
Note
Wherealargeandlongbulbousbowisarrangedadynamicpressurepsdyn istobeappliedunilaterally.Theunilateralpressure
can be calculated approximately as follows :
psdyn = po @ cF @ [kN/m2
]
po , cF , z and f according to Section 4, with f = 0,75.
For the effective area of psdyn, the projected area of the z-x-plane from forward to the collision bulkhead may be assumed.
Table 9.1 - Reduction coefficient nc
Number of cross ties nc
0
1
2
3
1,0
0,5
0,3
0,2
5.4 Web frames and stringers in 'tween decks and superstructure decks
Where the speed of the ship exceeds v0 = 1,6 [kn] or in ships with a considerable bow flare respectively, stringers and
transverses according to 5.3areto be fitted within0,1Lfromforwardperpendicularin'tweendeckspacesandsuperstructures.
The spacing of the stringers and transverses shall be less than 2,8 m. A considerable bow flare exists, if the flare angel
exceeds 40°, measured in the ship's transverse direction and related to the vertical plane.
5.5 Tripping brackets
5.5.1Between the point of greatest breadth of the ship at maximum draft and the collision bulkhead tripping brackets spaced
notmorethan2,6m,measuredvertically,accordingtoFig.9.3aretobefitted.Thethicknessofthebracketsistobedetermined
according to 5.2.1. Where proofofsafetyagainsttrippingisprovidedtrippingbrackets may partly or completely be dispensed
with.
5.5.2In the same range. in 'tween deck spaces and superstructures of 3 m and more in height, tripping brackets according
to 5.5.1 are to be fitted.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-159-320.jpg)
![A Section 9 - Framing System9-6/12
Fig. 9.3 - Tripping brackets
5.5.3Wherepeaksorotherspacesforwardofthecollisionbulkheadareintendedtobeusedastanks.trippingbracketsaccording
to 5.5.1 are to be fitted between tiers of beams or stringers.
5.5.4For ice strengthening, see Section 15.
6. Web frames in machinery spaces
6.1 Arrangement
6.1.1Intheengineandboilerroom,webframesaretobefitted. Generally, they should extend up to the uppermost continuous
deck. They are to be spaced not more than 5 times the frame spacing in the engine room.
6.1.2For combustion engines, web frames shall generally be fitted at the forward and aft ends of the engine. The web frames
are to be evenly distributed along the length of the engine.
6.1.3Where combustion engines are fitted aft, stringers spaced 2,6 m apart are to be fitted in the engine room, in alignment
with the stringers in the after peak, if any. Otherwise the main frames are to be adequately strengthened. The scantlings of
the stringers shall be similar to those of the web frames. At least one stringer is required where the depth up to the lowest
deck is less than 4 m.
6.1.4For the bottom structure in machinery spaces, see Section 8, C.
6.2 Scantlings
6.2.1The section modulus of web frames is not to be less than:
W = 0,8 @ e @ R2
@ ps @ k [cm3
]
The moment of inertia of web frames is not to be less than:
I = H (4,5 H n 3,5) ci @ 102
[cm4
] for 3m # H # 10m
I = H (7,25 H n 31) ci @ 102
[cm4
] for H > 10 m
ci = 1 + (Hu - 4) 0,07
The scantlings of the webs are to be calculated as follows :
depth h = 50 @ H [mm],
hmin = 250 mm
thickness t = [mm],
tmin = 8,0 mm.
6.2.2Ships with a depth of less than 3 m are to have web frames with web scantlings not less than 250 x 8 mm and
a minimum face sectional area of 12 cm2
.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-160-320.jpg)
![Section 9 - Framing System A, B 9-7/12
6.2.3 In very wide engine rooms it is recommended to provide side longitudinal bulkheads.
B. Bottom, Side- and Deck Longitudinals, Side Transverses
1. General
1.1 Longitudinals shall preferably be continuous through floor plates and transverses. Attachments of their webs to
the webs of floor plates and transverses are to be such that the support forces will be transmitted without exceeding a shear
stress of 100/k [N/mm2
].
For longitudinal frames and beams sufficient fatigue strength according to Section 20 is to be demonstrated.
Ahead of 0,1 L from F.P. webs of longitudinals are to be connected effectively at both ends. If the flare angle is more than
40° additional heel stiffeners or brackets are to be arranged.
1.2 Where longitudinals abut at transverse bulkheads or webs, brackets are to be fitted. These longitudinals are to
be attached to the transverse webs or bulkheads by brackets with the thickness of the stiffeners web thickness, and with
a length of weld at the longitudinals equal to 2 x depth of the longitudinals.
1.3 Outside the upper and the lower hull flange, the cross sectional areas stipulated in 1.2 may be reduced by 20%.
1.4 Where longitudinals are sniped at watertight floors and bulkheads, they are to be attached to the floors by brackets
of the thickness of plate floors, and with a length of weld at the longitudinals equal to 2 x depth of the bottom longitudinals.
(For longitudinal framing systems in double bottoms, see Section 8, B.7.)
1.5 For buckling strength of longitudinals see Section.3, F.2.3 and 3.
2. Definitions
k = material factor according to Section 2, B.2.
R = unsupported span [m], see also Fig.9.4
p = load [kN/m2
]
= pB,pB1 according to section 4.B.3. for bottom longitudinals.
= ps, ps1 or pe according to Section 4, B.2.1 for side longitudinals
= pl accordingtoSection4,D.1.1.for longitudinals atship's sides, at longitudinal bulkheads and inner
bottom in way of tanks.
For bottom longitudinals in way of tanks p due to tank pressure need not to be taken larger than
[kN/m2
]
For side longitudinals below Tmin p need not to be taken larger than:
[kN/m2
]
For the expression in the squared brackets no value < 0 shall be used.
= pd according to Section 4, D.2. for longitudinals at ship's sides, at deck and at longitudinal bulkheads in
tanks intended to be partially filled.
= pD according to Section 4, B.1. for deck longitudinals of the strength deck
= pDA according to Section 4, B.5. for exposed decks which are not to be treated as strength deck
= pi accordingtoSection4,C.2.forinnerbottomlongitudinals,however,notlessthantheloadcorresponding
to the distance between inner bottom and deepest load waterline
= pL according to Section 4, C.1. for longitudinals of cargo decks and for inner bottom longitudinals
p0 = according to Section 4, A.2.2
cF = according to Section 4, Table 4.1
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-161-320.jpg)
![B Section 9 - Framing System9-8/12
Tmin = smallest ballast draught
FL = Axial stress in the profile considered [N/mm2
] according to Section 5, D.1.
z = distance of structure [m] above base line.
xR = distance [mm] from transverse structure at I and J respectively (see Fig.9.4)
m = ; m $
ma = see A.1.2
mK =
RKI,RKJ = effective supporting length [mm] due to heel stiffeners and brackets at frame I and J (see Fig. 9.4)
RK =
c1 = For Rb # 0,3 @ hb, = 0 is to be taken.
hs, Rb, hb, he see Fig. 9.4
hs = height of the heel stiffener [mm]
Rb, hb = dimensions of the brackets [mm]
c2 = 3 in general
c2 = 1 for flanged brackets (see Fig. 9.4 (c))
he = height of bracket [mm] in the distance
xR = hs + 0,3 A hb of frame I and J respectively
If no heel stiffeners or brackets are arranged the respective values are to be taken as (hs, hb, ) = 0 (see Fig. 9.4 (d)).
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-162-320.jpg)
![Section 9 - Framing System B 9-9/12
Fig. 9.4 - End attachment
3. Scantlings of longitudinals and longitudinal beams
3.1 The section modulus WR and shear area AR of longitudinals and longitudinal beams of the strength deck is not to
be less than :
WR = @ m @ a @ R2
@ p [cm3
]
AR = (1 - 0,817 @ ma) 0,05 @ a @ R @ p @ k [cm2
],
The permissible stress Fpr is to be determined according to the following formulae :
Fpr = Fperm - *FL* [N/mm2
]
Fpr # [N/mm2
]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-163-320.jpg)
![B Section 9 - Framing System9-10/12
Fperm= [N/mm2
]
Fperm max = [N/mm2
]
For side longitudinals WR and AR shall not be less than :
WRmin= [cm3
]
ARmin = (1 – 0,817 @ ma) 0,037 @ a @ R @ psl @ k [cm2
]
psl according to Section 4,B.2.1.1 and 2.1.2 respectively.
ForfatiguestrengthcalculationsaccordingtoSection20,Table20.1bendingstressesduetolocalstiffenerbendingandlongitudinal
normal stresses due to global hull girder bending are to be combined. Bending stresses from local stiffener bending due to
lateral loads p can be calculated as follows:
for 0 # xR # Rk
FA = [N/mm2
]
for xR = hs + Rb
FB = FA @ m1 [N/mm2
]
Wa = section modulus of the profile [cm3
] including effective plate width according to Section 3, F.2.2
Fh = according to Section 3, L.1.
m1 = 1 – 4 @ c3 @ [1 – 0,75 @ c3]
for position B at I
c3I =
for position B at J
c3J =
The stresses at point A shall not be less than the stresses in adjacent fields (aft of frame I and forward of frame J respectively).
In way of curved shell plates (e.g. in the bilge area) section modulus WRmin, shear area ARmin, and stress FB can be reduced
by the factor CR.
CR =
t = thickness of shell plating [mm]
Ia = moment of inertia of the longitudinal frame [cm4
], including effective width
R = bending radius of the plate [m]
3.2 In tanks, the section modulus is not to be less than W2 according to Section 12, B.3.1.1.
3.3 Where the scantlings of longitudinals are determined by strength calculations, the total stress comprising local
bending and normal stresses due to longitudinal hull girder bending is not to exceed the total stress value Fperm and
Fperm max respectively as defined in 3.1.
3.4 If non symmentrical section are used additional stresses according to Section 3, L. shall be considered.
3.5 Wherenecessary, forlongitudinals between transversebulkheadsandsidetransversesadditionalstressesresulting
from the deformation of the side transverses are to be taken into account.
If no special verification of stresses due to web frame deformations is carried out, the following minimum values are to be
considered for fatigue strength verification of side longitudinals :
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-164-320.jpg)
![Section 9 - Framing System B 9-11/12
FDF = ± 0,1 @ [N/mm2
]
hw = web height of profile i [mm] (see Section 3, Fig. 3.3)
'Rb = ( hsI + RbI + hsJ + RbJ ) @ 10-3
[m] (see Fig. 9.4)
RR = unsupported web frame length [m] (see Fig. 9.5)
DF = height of web frame [m] (see Fig. 9.5)
Cp = weighting factor regarding location of the profile:
=
zRo = z-coordinate of web frame outset above basis [m] (see Fig. 9.5), zRo < T
CT = correction regarding location of the profile i to the waterline
= 0 # CT # 0,1
Fig. 9.5 - Definitions
3.6 Where struts are fitted between bottom and inner bottom longitudinals, see Section 8, B.7.2.
3.7 For scantlings of side longitudinals in way of those areas which are tobe strengthened against loads due to harbour
and tug manoeuvres see Section 6, C.5.
3.8 In the fore body where the flare angle " is more than 40° and in the aft body where the flare angle " is more than
75° the unsupported span of the longitudinals located above Tmin ! co shall not be larger than 2,6 m; co see Section 4,
A.2. Otherwise tripping brackets according to A.5.5 are to be arranged. co see Section 4, A.2.
3.9 The sideshelllongitudinalswithin the range from0,5 below the minimumdraught up to 2,0 mabove the maximum
draught and a waterline breadth exceeding 0,9 @ B are to be examined for sufficient strength against berthing impacts.
The force induced by a fender into the side shell may be determined by :
0 < D # 2 100 [t]: Pf = 0,08 · D [kN]
2 100 < D # 17 000 [t]: Pf = 170 [kN]
D > 17 000 [t]: Pf = D/100 [kN]
D = displacement of the ship [t]
Dmax= 100 000 t
3.10 In order to withstand the load Pf the section modulus W R of side shell longitudinals are not to be less than :
[cm3
]
k = Material factor
Mf = bending moment
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-165-320.jpg)
![B Section 9 - Framing System9-12/12
= [kNm]
R = unsupported length [m]
4. Side transverses
4.1 The section modulus W and shear area AW of side transverses supporting side longitudinals is not to be less than:
W = 0,55 @ e @ R2
@ p @ k [cm3
]
Aw = 0,05 @ e @ R @ p @ k [cm2
]
4.2 Where the side transverses are designed on the basis of strength calculations the following stresses are not to
be exceeded:
Fb = [N/mm2
]
J = [N/mm2
]
Fv = [N/mm2
]
Side transverses and their supports (e. g. decks) are to be checked according to Section 3, F. with regard to their buckling
strength.
Note :
The web thickness can be dimensioned depending on the size of the unstiffened web field as follows :
t =
a, b = length of side of the unstiffened web plate field, a b
f = 0,75 in general
= 0,9 in the aft body with extreme flare and in the fore body with flare angles " are less or equal 40°
= 1,0 in the fore body where flare angles " are greater than 40°
In the fore body where flare angles " are larger than 40° the web in way of the deck beam has to be stiffened.
4.3 In tanks the web thickness shall not be less than the minimum thickness according to Section 12, A.7., and the
section modulus and the cross sectional area are not to be less than W2 and Aw2 according to Section.12, B.3.
4.4 Thewebsofsidetransverseswithintherangefrom0,5mbelowtheminimumdraughtupto2,0mabovethemaximum
draught and a waterline breadthexceeding0,9ABaretobeexaminedforsufficientbucklingstrengthagainstberthingimpacts.
The force induced by a fender into the web frame may be determined as in 3.9.
4.5 In order to withstand the load Pf on the web frames, the following condition has to be met:
Pf < Pfu
Pf = see 3.9
Pfu = [kN]
C = 0,17 in general
C = 0,05 for web frame cutouts with free edges in way of continuous longitudinal
ts = web thickness of the side transverses [mm].
ReH = minimum nominal upper yield strength [N/mm2
] of the steel used for the webs of side transverses.
5. Strengthenings in the fore and aft body
In the fore and aft peak web frames and stringers or tiers of beams respectively are to be arranged according to A.5.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-166-320.jpg)
![Section 10 - Deck Beams and Supporting Deck Structures A 10-1/5
Section 10
Deck Beams and Supporting Deck Structures
A. General
1. Definitions
k = material factor according to Section 2, B.2.
R = unsupported span [m] according to Section 3, C.
e = width of deck supported, measured from centre to centre of the adjacent unsupported fields [m]
p = deck load pD, pDA or pL [kN/m2
], according to Section 4, B. and C.
c = 0,55
= 0,75 for beams, girders and transverses which are simply supported on one or both ends.
Ps = pillar load
= P @ A + Pi [kN]
A = load area for one pillar [m2
]
Pi = load from pillars located above the pillar considered [kN]
8s = degree of slenderness of the pillar
= $ 0,2
Rs = length of the pillar [cm]
ReH = nominal yield point [N/mm2
]
E = Young’s modulus [N/mm2
]
= 2,06 x 105
is = radius of gyration of the pillar
= [cm]
= 0,25 ds for solid pillars of circular cross section
= 0,25 for tubular pillars
Is = moment of inertia of the pillar [cm4
]
As = sectional area of the pillar [cm2
]
ds = pillar diameter [cm]
da = outside diameter of pillar [cm]
di = inside diameter of pillar [cm].
ma = factor according to Section 9, A.1.2
2. Permissible stresses
Where the scantlings of girders not forming part of the longitudinal hull structure, or of transverses, deck beams, etc. are
determined by means of strength calculations the following stresses are not to be exceeded:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-167-320.jpg)
![A, B Section 10 - Deck Beams and Supporting Deck Structures10-2/5
Fb = [N/mm2
]
J = [N/mm2
]
Fv = [N/mm2
]
3. Buckling strength
The buckling strength of the deck structures is to be examined according to Section 3, F. For this purpose the design stresses
according to Section 5, D.1. and the stresses due to local loads are to be considered.
B. Deck Beams and Girders
1. Transverse deck beams and deck longitudinals
The section modulus Wd and shear area Ad of transverse deck beams and of deck longitudinals between 0,25 H and 0,75
H above base line is to be determined by the following formula:
Wd = c @ a @ p . R2
. k [cm3
]
Ad = (1 - 0,817 @ ma) 0,05 @ a @ R @ p @ k [cm2
]
2. Deck longitudinals in way of the upper and lower hull flange
Thesectionmodulusofdecklongitudinalsofdeckslocatedbelow0,25Hand/orabove0,75Hfrombaselineistobecalculated
according to Section 9, B.
3. Attachment
3.1 Transverse deck beams are to be connected to the frames by brackets according to Section 3, D.2.
3.2 Deck beams crossing longitudinal walls and girders may be attached to the stiffeners of longitudinal walls and
the webs of girders respectively by welding without brackets.
3.3 Deck beams may be attached to hatchway coamings andgirdersbydoublefilletweldswherethereisnoconstraint.
The length of weld is not to be less than 0,6 x depth of the section.
3.4 Where deck beams are to be attached to hatchway coamingsand girders of considerable rigidity (e.g. box girders),
brackets are to be provided.
3.5 Within 0,6 L amidships, the arm lengths of the beam brackets in single deck ships are to be increased by 20%.
The scantlings of the beam brackets need, however, not be taken greater than required for the Rule section modulus of the
frames.
3.6 Regarding the connection of deck longitudinals to transverses and bulkheads, Section 9, B.1. is to be observed.
4. Girders and transverses
4.1 The section modulus W and shear area Aw are not to be less than:
W = c @ e @ R2
@ p @ k [cm3
].
Aw = 0,05 @ p @ e @ R @ k [cm2
].
4.2 The depth of girders is not to be less than 1/25 of the unsupported span. The web depth of girders scalloped for
continuous deck beams is to be at least 1,5 times the depth of the deck beams.
Scantlings of girders of tank decks are to be determined according to Section 12, B.3.
4.3 Where a girder does not have the same section modulus throughout all girder fields, the greater scantlings are to
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-168-320.jpg)
![Section 10 - Deck Beams and Supporting Deck Structures B, C 10-3/5
be maintained above the supports and are to be reduced gradually to the smaller scantlings.
4.4 End attachments of girders at bulkheads are to be so dimensioned that the bending moments and shear forces can
be transferred. Bulkhead stiffeners under girders are to be sufficiently dimensioned to support the girders.
4.5 FaceplatesaretobestiffenedbytrippingbracketsaccordingtoSection3,H.2.5.Atgirdersofsymmetricalsection,
they are to be arranged alternately on both sides of the web.
4.6 For girders in line of the deckhouse sides under the strength deck, see Section 16, A.3.2.
4.7 For girders forming part of the longitudinal hull structure and for hatchway girders see E.
5. Supporting structure of windlasses and chain stoppers
5.1 Forthesupportingstructureunderwindlassesandchainstoppers,thefollowingpermissiblestressesaretobeobserved:
Fb = [N/mm2
]
J = [N/mm2
]
Fv # [N/mm2
]
5.2 The acting forces are to be calculated for 80% and 45% respectively of the rated breaking load of the chain cable,
i.e.:
– for chain stoppers 80%
– for windlasses 80% , where chain stoppers are not fitted.
– for windlasses 45%,where chain stoppers are fitted.
SeealsoRulesforMachineryInstallations,VolumeIII,Section14,D.andRulesforMaterials,VolumeV,Section 13,Table.13.7.
C. Pillars
1. General
1.1 Structural members at heads and heels of pillars as well as substructures are to be constructed according to the
forces they are subjected to. The connection is to be so dimensioned that at least 1 cm2
cross sectional area is available for
10 kN of load.
Where pillars are affected by tension loads doublings are not permitted.
1.2 Pillars in tanks are to be checked for tension. Tubular pillars are not permitted in tanks for flammable liquids.
1.3 For structural elements of the pillars' transverse section, sufficient buckling strength according to Section.3,
F. hastobeverified.Thewallthicknessoftubularpillars which may be expected to bedamagedduringloadingandunloading
operations is not to be less than:
tw = 4,5 + 0,015 da [mm] for da # 300 mm
tw = 0,03 da [mm] for da > 300 mm
da = outside diameter of tubular pillar [mm]
1.4 Pillars also loaded by bending moments have to be specially considered.
2. Scantlings
The sectional area of pillars is not to be less than:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-169-320.jpg)
![C, D Section 10 - Deck Beams and Supporting Deck Structures10-4/5
As req= [cm2
]
Fp = permissible compressive stress [N/mm2
]
=
6 = reduction factor
=
k =
np = 0,34 for tubular and rectangular pillars
= 0,49 for open sections
S = safety factor
= 2,00 in general
= 1,66 in accommodation area
D. Cantilevers
1. General
1.1 In order to withstand the bending moment arising from the load P, cantilevers for supporting girders, hatchway
coamings, engine casings and unsupported parts of decks are to be connected to transverses, web frames, reinforced main
frames, or walls.
1.2 When determining the scantlings of the cantilevers and the aforementioned structural elements, it is to be taken
into consideration that the cantilever bending moment depends on the load capacity of the cantilever, the load capacity being
dependent on the ratio of rigidity of the cantilever to that of the members supported by it.
1.3 Face plates are to be secured against tilting by tripping brackets fitted to the webs at suitable distances (see also
Section 3, H.2.).
1.4 Particulars of calculation, together with drawings of the cantilever construction are to be submitted for approval.
2. Permissible stresses
2.1 When determining the cantilever scantlings, the following permissible stresses are to be observed:
.1 Where single cantilevers are fitted at greater distances:
bending stress:
Fb = [N/mm2
]
shear stress:
J = [N/mm2
]
.2 Where several cantilevers are fitted at smaller distances (e.g. at every frame):
bending stress:
Fb = [N/mm2
].
shear stress:
J = [N/mm2
]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-170-320.jpg)
![Section 10 - Deck Beams and Supporting Deck Structures E 10-5/5
equivalent stress:
Fv < = [N/mm2
].
.3 The stresses in web frames are not to exceed the values specified in .1 and .2 above.
E. Hatchway Girders and Girders Forming Part of the Longitudinal Hull Structure
1. Thescantlingsoflongitudinalandtransversehatchwaygirdersaretobedeterminedonthebasisofstrengthcalculations.
The calculations are to be based upon the deck loads calculated according to Section 4, B. and.C.
2. The hatchway girders are to be so dimensioned that the stress values given in Table 10.1 will not be exceeded.
Table 10.1 - Maximum stress values FR for hatchway girders
Longitudinal coaming and girders of the strength deck All other hatchway girders
upper and lower flanges :
FR = [N/mm2
]
FR = [N/mm2
]
deck level:
FR = [N/mm2
]
3. For continuous longitudinal coamings the combined stress resulting from longitudinal hull girder bending and
local bending of the longitudinal coaming is not to exceed the following value :
FL + FR # [N/mm2
]
FR = local bending stress in the ship's longitudinal direction
FL = design longitudinal hull girder bending stress according to Section 5, D.1.
4. The equivalent stress is not to exceed the following value:
Fv,all = [N/mm2
] for L < 90 m
= [N/mm2
] for L $ 90 m
=
Fx = FL + FR
Fy = stress in the ship's transverse direction
J = shear stress
Jmax = [N/mm2
].
The individual stresses FR and Fy are not to exceed 150/k [N/mm2
].
5. The requirements regarding buckling strength according to A.3. are to be observed.
6. Weldings at the top of hatch coamings are subject to special approval.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-171-320.jpg)
![Section 11 - Watertight Bulkheads A 11-1/8
Section 11
Watertight Bulkheads
A. General
1. Watertight subdivision
1.1 All ships are to have a collision bulkhead, a stern tube bulkhead and one watertight bulkhead at each end of the
engine room. In ships with machinery aft, the stern tube bulkhead may substitute the aft engine room bulkhead.
1.2 For ships without longitudinal bulkheads in the cargo hold area the number of watertight transverse bulkheads
should, in general, not be less than given in Table 11.1.
Table 11.1 - Number of watertight transverse bulkheads
L
[m]
Arrangement of machinery space
aft elsewhere
L 65
65 < L 85
85 < L 105
105 < L 125
125 < L 145
145 < L 165
165 < L 185
3
4
4
5
6
7
8
4
4
5
6
7
8
9
L > 185 to be special considered
1.3 One or more of the watertight bulkheads required by 1.2, may be dispensed with where the transverse strength
of the ship is adequate. The number of watertight bulkheads will be entered into the Register.
1.4 Number and location of transverse bulkheads fitted in addition to those specified in 1.1 are to be so selected as
to ensure sufficient transverse strength of the hull.
1.5 For ships which require proof of survival capability in damaged conditions, the watertight sub-division will be
determined by damage stability calculations. For oil tankers see Section 24, A.2., for passenger vessels see Section
29-I, C., for special purpose ships see Section 29-II,.C., for cargo ships of more than 100 m in length see Section 36
and for supply vessels see Section 34, A.2. For liquefied gas tankers see Rules for Ships Carrying Liquefied Gases in
Bulk, Volume IX, Section 2, for chemical tankers see Rules for Ships Carrying Dangerous Chemicals in Bulk, Volume X,
Section 2.
2. Arrangement of watertight bulkheads
2.1 Collision bulkhead
2.1.1A collision bulkhead shall be located at a distance from the forward perpendicular of not less than 0,05 Lc or 10
m, whichever is the less, and, except as may be permitted by the Administration, not more than 0,08 Lc or 0,05 Lc
+ 3 m, whichever is the greater
2.1.2Where any part of the ship below the waterline extends forward of the forward perpendicular, e.g., a bulbous bow,
the distance x shall be measured from a point either:
– at the mid-length of such extension, i.e. x = 0,5 @ a
– at a distance 0,015 Lc forward of the forward perpendicular, i.e. x = 0,015 @ Lc, or
– at a distance 3 m forward of the forward perpendicular, i.e. x = 3,0 m whichever gives the smallest measurement.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-173-320.jpg)
![A, B Section 11 - Watertight Bulkheads11-4/8
The closing mechanism is to be safely operable from each side of the bulkhead and from above the freeboard deck. If closing
ofthedoorcannotbeobservedwithcertainty,anindicatoristobefittedwhichshows,ifthedoorisclosedoropen;theindicator
is to be installed at the position from which the closing mechanism is operated.
3.4 Penetrations through watertight bulkheads
Where bulkhead fittings are penetrating watertight bulkheads, care is to be taken to maintain water tightness by observation
of Chapter II-1 Reg. 12 of SOLAS as amended. For penetrations through the collision bulkhead, 2.1.6 is to be observed.
B. Scantlings
1. General, Definitions
1.1 Where holds are intended to be filled with ballast water, their bulkheads are to comply with the requirements of
Section 12.
1.2 Bulkheads of holds intended to be used for carrying ore are to comply with the requirements of Section 23, as
far as their strength is concerned.
1.3 Definitions
tK = corrosion addition according to Section 3, K.
a = spacing of stiffeners [m]
R = unsupported span [m], according to Section 3, C.
p = 9,81 @ h [kN/m2
]
h = distance from the load centre of the structure to a point 1 m above the bulkhead deck at the ship side, for
the collision bulkhead to a point 1 m above the upper edge of the collision bulkhead at the ship side.
For cargo ships with proven damage stability see Section 36, E.2.
For the definition of "load centre" see Section.4. A.2.1.
cp, cs = coefficients according to Table 11.2
f =
ReH = minimum nominal upper yield point [N/mm2
] according to Section 2, B.2.
Table 11.2 - Coefficients cp and cs
Coefficient cp and cs
Collision
bulkhead
Other
bulkheads
Plating cp
Stiffeners,
corrugated
bulkhead
elements
cs: in case of constraint of both ends 0,33 @ f 0,265 @ f
cs: in case of simply support of one end and
constraint at the other end
0,45 @ f 0,36 @ f
cs: both ends simply supported 0,66 @ f 0,53 @ f
For the definition of "constraint" and "simply supported", see Section.3. D.1.
2. Bulkhead plating
2.1 The thickness of the bulkhead plating is not to be less than :
t = [mm]
tmin = [mm]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-176-320.jpg)
![Section 11 - Watertight Bulkheads B 11-5/8
For ships with large deck openings according to Section.5, F.1.2, the plate thickness of transverse bulkheads is not to be less
than:
t = c @ + tK [mm]
where
)R = distancefromthemidofholdbeforetothemidofholdaftoftheconsideredtransversebulkhead or supporting
bulkhead [m]
a, b = spacing of stiffeners [m]
tK = corrosion addition [mm] according to Section 3, K.
ReH = nominal upper yield stress of material [N/mm2
] according to Section 2, B.2.
F1 = correction factor according to Section 3, F.1.
c = 13 in general
= 15 below z = 0,2 H and above 0,8 H and generally in the fore ship before x/L = 0,8
2.2 In small ships, the thickness of the bulkhead plating need not exceed the thickness of the shell plating for a frame
spacing corresponding to the stiffener spacing.
2.3 The stern tube bulkhead is to be provided with a strengthened plate in way of the stern tube.
2.4 In areas where concentrated loads due to ship manoeuvres at terminals, may be expected, the buckling, strength
of bulkhead plate fields directly attached to the side shell, is to be examined according to Section 9, B.4.4 and 4.5.
2.5 When determining the bulkhead scantlings of tanks, connected by cross-flooding arrangements, the increase in
pressure head at the immerged side that may occur at maximumheeling in the damaged condition shall be taken into account.
3. Stiffeners
3.1 The section modulus of bulkhead stiffeners is not to be less than:
W = [cm3
]
3.2 In horizontal part of bulkheads, the stiffeners are also to comply with the rules for deck beams according to
Section 10.
3.3 Thescantlingsofthebracketsaretobedeterminedindependence ofthesectionmodulusofthestiffenersaccording
to Section 3, D.2. If the length of the stiffener is 3,5 m and over, the brackets are to extend to the next beam or the next floor.
3.4 Unbracketed bulkhead stiffeners are to be connected to the decks by welding. The length of weld is to be at least
0,6 x depth of the section.
3.5 If the length of stiffeners between bulkhead deck and the deck below is 3 m and less, no end attachment according
to 3.4 is required. In this case the stiffeners are to be extended to about 25 mm from the deck and sniped at the ends. (See
also Section 3, C.3.)
3.6 Bulkhead stiffeners cut in way of watertight doors are to be supported by carlings or stiffeners.
4. Corrugated bulkheads
4.1 The plate thickness of corrugated bulkheads is not to be less than required according to 2.1. For the spacing a,
the greater one of the values b or s [m] according to 4.3 is to be taken.
4.2 The section modulus of a corrugated bulkhead element is to be determined according to 3.1. For the spacing a,
the width of an element e, [m] according to 4.3 is to be taken. For the end attachment see Section 3, D.4.
4.3 Theactualsectionmodulusofacorrugatedbulkheadelementistobe assessedaccordingtothefollowingformulae:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-177-320.jpg)
![B Section 11 - Watertight Bulkheads11-6/8
W = t @ d [cm3
]
where, carling or similar elements can not be fitted in line with the web strips
W = t @ d (d + t) [cm3
]
e = width of element [cm]
b = breadth of face plate [cm]
s = breadth of web plate [cm]
d = distance between face plates [cm]
t = plate thickness [cm]
" 45E
Fig. 11.2 Element of corrugated bulkhead
4.4 For watertight bulkheads of corrugated type on ship according to Section 5, G. See Section 23, E.
5. Primary Supporting Members
5.1 General
Primary supporting members are to be dimensioned using direct calculation as to ensure the stress criteria according to 5.3.1
for normal operation and the criteria according to 5.3.2 if any cargo hold is flooded.
Regarding effective breadth and buckling proof in each case Section 3, E. and F. has to be observed.
In areas with cut-outs 2nd-order bending moments shall be taken into account.
5.2 Load assumptions
5.2.1 Loads during operation
Loads during operation are the external water pressure, see Section 4, and the loads due to cargo and filled tanks, see Section
17, B.1.7, Section 21, G. and if relevant depending on the deck opening Section 5, F.
5.2.2 Loads in damaged condition
The loads in case of hold flooding result from 1.3 considering Section 36, D.2.
5.3 Strength criteria
5.3.1 Load case "operation"
With loads according to 5.2.1 the following permissible stresses are to be used :
Fv = # [N/mm2
]
FN = normal stress, FN # [N/mm2
]
J = shear stress, J # [N/mm2
]
k = material factor according Section 2, B.2.
If necessary Section 5, F.2. shall be observed in addition.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-178-320.jpg)
![Section 11 - Watertight Bulkheads B 11-7/8
5.3.2 Load case "hold flooding"
The thickness of webs shall not be smaller than:
tw = [mm]
Jperm = 727 [N/mm2
]
Q = shear force [kN]
hw = height of web [mm]
a, b = lengths of stiffeners of the unstiffened web field, where hw $ b # a
5.3.3 Dimensioning of Primary Supporting Members
For dimensioning of primary supporting members plastic hinges can be taken into account.
Thiscanbedoneeitherbyanon-linearcalculationofthetotalbulkheadorbyalineargirdergrillagecalculationoftheidealized
bulkhead.
When a linear girder grillage calculation is done, only those moments and shear forces are taken as boundary conditions at
the supports, which can be absorbed by the relevant sections at these locations in full plastic condition.
The plastic moments [kNm] are calculated by:
Mp =
c = 1,1 for the collision bulkhead
= 1,0 for cargo hold bulkheads
The plastic shear forces [kN] are calculated by :
Qp =
For the field moments and shear forces resulting thereof the sections are defined in such a way that the condition
Fv # ReH
is fulfilled.
The plastic section moduli are to be calculated as follows:
Wp = Ai @ epi [cm3
]
epi = distance [mm] of the centre of the partial area Ai fromthe neutral axis of the yielded section. The neutral axis shall
not be taken in a position lower than the lowest point of the web.
Ai = effective partial area [mm2
] considering Section.3, F.2.2.
In this connection the area As of webs transferring shear shall not be taken into account.
That part of the web height related to shear transfer shall not be less than:
)hw = hw @
twa = as built thickness of the web $ tw
Where girders are built up by partial areas Ai with different yield stress ReHi the plastic moments are calculated by:
Mp = [kNm]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-179-320.jpg)
![B, C Section 11 - Watertight Bulkheads11-8/8
The plastic shear forces are:
Qp = [kN]
6. Watertight longitudinal structures
The plating and stiffeners of watertight longitudinal structures shall be dimensioned according to Table 11.2, column "Other
bulkheads".
C. Shaft Tunnels
1. General
1.1 Shaftandstuffingboxaretobeaccessible.Whereoneormorecompartmentsaresituatedbetweensterntubebulkhead
and engine room, a watertight shaft tunnel is to be arranged. The size of the shaft tunnel is to be adequate for service and
maintenance purposes.
1.2 The access opening between engine room and shaft tunnel is to be closed by a watertight sliding door complying
with the requirements according to A.3.3. For extremely shortshaft tunnels watertight doorsbetweentunnelandengineroom
may be dispensed with subject to special approval.
In this connection see also SOLAS 74, Chapter II-1, Regulation 11/8 as amended.
1.3 Tunnel ventilators and the emergency exit are to be constructed watertight up to the freeboard deck.
2. Scantlings
2.1 The plating of the shaft tunnel is to be dimensioned as for a bulkhead according to B.2.1.
2.2 The plating of the round part of tunnel tops may be 10 % less in thickness.
2.3 In the range of hatches, the plating of the tunnel top is to be strengthened by not less than 2 mm unless protected
by a ceiling.
On container ships this strengthening can be dispensed with.
2.4 The section modulus of shaft tunnel stiffeners is to be determined according to B.3.1.
2.5 Horizontal parts of the tunnel are to be treated as horizontal parts of bulkheads and as cargo decks respectively.
2.6 Shaft tunnels in tanks are to comply with the requirements of Section 12.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-180-320.jpg)
![A Section 12 - Tank Structures12-2/10
condensate water and potable water by cofferdams1)
.
5.2 Upon special approval on small ships the arrangement of cofferdams between oil fuel and lubricating oil tanks
may be dispensed with provided that:
.1 the common boundary is continuous, i.e. it does not abut at the adjacent tank boundaries, see Fig. 12.1
Where the common boundary cannot be constructed continuously according to Fig. 12.1, the fillet welds on
both sides of the common boundary are to be welded in two layers and the throat thickness is not to be less than
0,5 @ t (t = plate thickness);
Fig. 12.1 - Continuous common boundary replacing a cofferdam
.2 stiffeners or pipes do not penetrate the common boundary;
.3 the corrosion allowance tK for the common boundary is not less than 2,5 mm.
5.3 Fuel oil tanks adjacent to lubricating oil circulation tanks are not permitted.
5.4 For fuel tanks which are heated up to a temperature which is higher than the flash point – 10 °C of the relevant
fuel, Rules for Machinery Installations, Volume III, Section.10, B.5.is to be observed specifically.
6. Tanks for heated liquids
6.1 Where heated liquids are intended to be carried in tanks, acalculationofthermalstressesis required, if the carriage
temperature of the liquid exceeds the following values :
T = 65EC in case of longitudinal framing,
= 80EC in case of transverse framing.
6.2 The calculations are to be carried out for both temperatures, the actual carriage temperature and the limit
temperature T according to 6.1.
The calculations are to give the resultant stresses in the hull structure based on a sea water temperature of 0EC and an air
temperature of 5EC.
Constructionalmeasuresand/orstrengtheningswillberequiredonthebasisoftheresultsofthecalculationforbothtemperatures.
7. Minimum thickness
7.1 The thickness of all tank structures is not to be less than the following minimum value :
tmin = 5,5 + 0,02 L [mm]
7.2 For fuel oil, lubrication oil and fresh water tanks tmin need not be taken greater than 7,5 mm
7.3 For ballast tanks of dry cargo ships tmin need not be taken greater than 9,0 mm.
7.4 For oil tankers see Section 24, A.14.
1)
For Indonesian flag ship, the cofferdams are also required between accommodation spaces and oil tanks.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-182-320.jpg)
![Section 12 - Tank Structures A 12-3/10
8. Plating and stiffeners in the propeller area and in the engine room
8.1 General
Fromavibrationpointofviewshellandtankstructuresinthevicinityofthepropeller(s)andthemainengineshouldbedesigned
such that the design criteria defined in 8.3 to 8.5 are fulfilled (see also Section 6, F.1 and Section 8, A.1.2.3).
8.2 Definitions
fplate
2)
= lowestnaturalfrequencyofisotropicplatefieldunderconsiderationofadditionaloutfittingandhydrodynamic
masses [Hz]
fstiff
2)
= lowest natural frequency of stiffener under consideration of additional outfitting and hydrodynamic
masses [Hz]
dp = propeller diameter [m]
r = distance of plate field or stiffener to 12 o'clock propeller blade tip position [m]
dr = ratio
" = flare angle of frame section in propeller plane measured between a vertical line and the tangent to the
bottom shell plating
n = maximum propeller shaft revolution rate [1/min]
z = number of propeller blades
fblade = propeller blade passage excitation frequency at n [Hz]
= [Hz]
ne = maximum main engine revolution rate [1/min]
nc = number of cylinders of main engine
kstroke = number indicating the type of main engine
= 1,0 for 2-stroke (slow-running) main engines
= 0,5 for 4-stroke (medium speed) main engines 3)
fignition = main engine ignition frequency at ne
= [Hz]
8.3 Shell structures in propeller area
Plate fields and stiffeners of shell structures in vicinity of the propeller(s) within dr = 3 should fulfil the following frequency
criteria:
for " $ 60o
for " < 60o
dr needs not to be taken less than 1,0.
8.4 Tank structures in propeller area
Forvesselwithasinglepropeller,platefieldsandstiffenersoftankstructureswithindr =5shouldfulfilthefollowingfrequency
criteria :
2)
The natural frequencies of plate fields and stiffeners can be estimated by approved computer program
3)
The number is valid for in-line engines. The ignition frequency for V-engines depends on the V-angle of the cylinder banks and can be obtained
from the engine manufacturer.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-183-320.jpg)
![A, B Section 12 - Tank Structures12-4/10
for " $ 60o
for " < 60o
dr needs not to be taken less than 1,3.
8.5 Tank structures in main engine area
For vessels with a single propeller, plate fields and stiffeners of tanks located in the engine room should at all filling states
fulfil the frequency criteria as summarized in Table 12.1.
Generally, direct connections between transverse engine top bracings and tank structures shall be avoided. Pipe fittings at
tank walls etc. shall be designed in such a way that the same frequency criteria as given for plates are fulfilled.
B. Scantlings
1. Definitions
k = material factor according to Section 2, B.2.
a = spacing of stiffeners or load width [m]
R = unsupported span [m] according to Section 3, C.
p = load p1 or pd [kN/m2
] according to Section 4, D.; the greater load to be taken.
For tank structures of tanks adjacent to the shell the pressure p below Tmin need not be larger than :
p = [kN/m2
]
Tmin = smallest design ballast draught [m]
z = distance of structural member above base line [m]
p2 = load [kN/m2
] according to Section 4, D.1.
tK = corrosion addition according to Section 3, K.
h = filling height of tank [m]
et = characteristic tank dimension Rt or bt [m]
Rt = tank length [m]
bt = tank breadth [m]
FpR = [N/mm2
]
FL = membrane stress at the position considered [N/mm2
] according to Section 5,D.1
JL = shear stress [N/mm2
] at the position considered see also Section 5,D.1.
nf = 1,0 for transverse stiffening
= 0,83 for longitudinal stiffening
For the terms "constraint" and "simply supported" see Section 3, D.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-184-320.jpg)
![Section 12 - Tank Structures B 12-5/10
Table 12.1 - Frequency criteria
Engine type Mounting type Application area Frequency criteria
Slow speed Rigid Tanks within engine room
fplate > 1,2 . fignition
fstiff > 1,2 . fignition
and
fplate < 1,8 . fignition or
fplate > 2,2 . fignition
Medium speed
Rigid or semi-resilient Tanks within engine room
fplate < 0,8 . fignition or
fplate > 1,2 . fignition
and
fstiff < 0,8 . fignition or
fstiff > 1,2 . fignition
Resilient
Tanks within engine
length up to next platform
deck above inner bottom
fplate < 0,9 . fignition or
fplate < 1,1 . fignition
2. Plating
2.1 The plate thickness is not to be less than:
t1 = 1,1 @ a @ + tK [mm]
t2 = 0,9 @ a @ + tK [mm].
2.2 Abovetherequirementsspecifiedin2.1thethicknessoftankboundaries(includingdeckandinnerbottom)carrying
also normal and shear stresses due to longitudinal hull girder bending is not to be less than :
t = [mm]
2.3 Proof of plating of buckling strength of longitudinal and transverse bulkheads is to be carried out according to
Section 3, F. For longitudinal bulkheads the design stresses according to Section 5, D.1. and the stresses due to local loads
are to be considered.
3. Stiffeners and girders
3.1 Stiffeners and girders, which are not considered as longitudinal strength members
3.1.1The section modulus of stiffeners and girders constrained at their ends, is not to be less than:
W1 = 0,55 @ a @ R2
@ p @ k [cm3
]
W2 = 0,44 @ a @ R2
@ p2 @ k [cm3
].
Where one or both ends are simply supported, the section moduli are to be increased by 50%.
The shear area of the girder webs is not to be less than:
Aw1 = 0.05 @ a @ R @ p @ k [cm2
]
Aw2 = 0,04 @ a @ R @ p2 @ k [cm2
].
Aw2 is to be increased by 50 % at the position of constraint for a length of 0,1 R.
The buckling strength of the webs is to be checked according to Section 3, F.
3.1.2Wherethescantlingsofstiffenersandgirdersaredeterminedaccordingtostrengthcalculations,thefollowingpermissible
stress values apply :
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-185-320.jpg)
![B Section 12 - Tank Structures12-6/10
S if subjected to load p :
Fb = [N/mm2
]
J = [N/mm2
]
Fv = [N/mm2
]
S if subjected to load p2 :
Fb = [N/mm2
]
J = [N/mm2
]
Fv = [N/mm2
]
3.2 Stiffeners and girders, which are to be considered as longitudinal strength members
3.2.1The section moduli and shear areas of horizontal stiffeners and girders are to be determined according to Section 9,
B.3.1 as for longitudinals. In this case for girders supporting transverse stiffeners the factors m = 1 and ma = 0 are to
be used.
3.2.2 Regarding buckling strength of girders the requirements of 2.3 are to be observed.
3.3 The scantlings of beams and girders of tank decks are also to comply with the requirements of Section 10.
3.4 For frames in tanks, see Section 9, A.2.2.
3.5 ThestiffenersoftankbulkheadsaretobeattachedattheirendsbybracketsaccordingtoSection3,D.2.Thescantlings
of the brackets are to be determined according to the section modulus of the stiffeners. Brackets have to be fitted where the
length of the stiffeners exceeds 2 m.
The brackets of stiffeners are to extend to the next beam, the next floor, the next frame, or are to be otherwise supported at
their ends.
3.6 Where stringersoftransverse bulkheads are supported at longitudinal bulkheads or at the side shell, the supporting
forcesofthesestringersaretobeconsideredwhendeterminingthe shear stress in the longitudinal bulkheads. Likewise, where
vertical girders of transverse bulkheads are supported at deck or inner bottom, the supporting forces of these vertical girders
are to be considered when determining the shear stresses in the deck or inner bottom respectively.
The shear stress introduced by the stringer into the longitudinal bulkhead or side shell may be determined by the following
formulae:
= [N/mm2
]τSt
Pst = supporting force of stringer or vertical girder [kN]
bSt = breadth of stringer or depth of vertical girder including end bracket (if any) [m] at the supporting point
t = see 2.2
The additional shear stress is to be added to the shear stress JL due to longitudinal bending according to SectionτSt
5, D.1. in the following area:
– 0,5 m on both sides of the stringer in the ship's longitudinal direction
– 0,25 . bSt above and below the stringer
Thereby the following requirement shall be satisfied :
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-186-320.jpg)
![Section 12 - Tank Structures B, C 12-7/10
4. Corrugated bulkheads
4.1 Theplatethicknessesofcorrugatedbulkheadsaswellastherequiredsectionmoduliofcorrugatedbulkheadelements
are to be determined according to 2. and 3., proceeding analogously to Section 11, B.4.
The plate thickness is not to be less than tmin, according to A.7, or
S if subjected to load p
tcrit = [mm]
S if subjected load p2
tcrit = [mm]
FD = compressive stress [N/mm2
]
b = breadth of face plate strip [mm]
4.2 For the end attachment Section 3, D.4. is to be observed.
5. Thickness of clad plating
5.1 Where the yieldpointofthe claddingisnotless thanthat of the base material the plate thickness is to be determined
according to 2.1.
5.2 Where the yield point of the cladding is less than that of the base material the plate thickness is not to be less than:
t1 = 0,55 @ a [mm]
t2 = 0,45 @ a [mm]
for one side clad steel:
A = 0,25 S
for both side clad steel:
A = 0,25 S
t = plate thickness including cladding [mm]
tp = thickness of the cladding [mm]
r =
Rep = minimum nominal upper yield point of the cladding [N/mm2
] at service temperature
ReH = minimum nominal upper yield point of the base material [N/mm2
] according to Section 2, B.2.
5.3 The plate thicknesses determined in accordance with 5.1 and 5.2 respectively may be reduced by 0,5 mm. For
chemicaltankershoweverthereductions as perRulesforShipsCarryingDangerousChemicalsinBulk,VolumeX,Section.4,
4 – 0.1.3 apply.
C. Tanks with Large Lengths or Breadths
1. General
Tanks with lengths Rt > 0,1 L or breadths bt > 0,6 B (e.g. hold spaces for ballast water) which are intended to be partially
filled, are to be investigated to avoid resonance between theliquidmotionandthepitchorrollmotionoftheship.Ifnecessary,
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-187-320.jpg)
![C, D Section 12 - Tank Structures12-8/10
critical tank filling ratios are to be avoided. The ship's periods of pitch and roll motion as well as the natural periods of the
liquid in the tank may be determined by the following formulae:
Natural period of liquid in tank :
TR,b = [s]
f = hyperbolic function as follows:
= tanh
Period of wave excited maximum pitch motion :
Ts = [s]
= ahead speed of ship [kn] as defined in Section 1, H.5.
Period of roll motion :
Tr = [s]
cr = 0,78 in general
= 0,70 for tankers in ballast
. 0,07 @ B in general
. 0,12 @ B for tankers and bulk carriers.
2. Hold spaces for ballast water
Inadditiontotherequirementsspecifiedunder1.aboveforholdspacesofdrycargoshipsandbulkcarriers,whichareintended
to be filled with ballast water, the following is to be observed:
.1 For hold spaces only permitted to be completely filled, a relevant notice will be entered into the Certificate.
.2 Adequate venting of the hold spaces and of the hatchway trunks is to be provided.
.3 For frames also Section 9, A.2.2 is to be observed.
D. Vegetable Oil Tanks
1. Further to the regulations stipulated under A. and B. for vegetable oil tanks, the following requirements are to
be observed.
2. Tanks carrying vegetable oil or similar liquids, the scantlings of which are determined according to B., are to be
either fully loaded or empty. A corresponding note will be entered into the Certificate.
Thesetanksmaybepartiallyfilledprovided they are subdivided according to A.1.2. Fillingratiosbetween70and90%should
be avoided.
3. Intankscarryingvegetableoilorsimilarliquidssufficientairpipesaretobefittedforpressureequalizing.Expansion
trunks of about 1 % of the tank volume are to be provided. Where the tank is subdivided by at least one centre line bulkhead,
3% of the tank may remain empty and be used as expansion space.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-188-320.jpg)
![Section 12 - Tank Structures E, F, G 12-9/10
E. Detached Tanks
1. General
1.1 Detached tanks are to be adequately secured against forces due to the ship's motions.
1.2 Detached tanks in hold spaces are also to be provided with anti floatation devices. It is to be assumed that the hold
spaces are flooded to the load waterline. The stresses in the anti floatation devices caused by the floatation forces are not
to exceed the material's yield stress.
1.3 Detached oil fuel tanks should not be installed in cargo holds. Where such an arrangement cannot be avoided,
provision is to be made to ensure that the cargo cannot be damaged by leakage oil.
1.4 Fittings and pipings on detached tanks are to be protected by battens, and gutterways are to be fitted on the outside
of tanks for draining any leakage oil.
2. Scantlings
2.1 The thickness of plating of detached tanks is to be determined according to B.2.1 using the formulae for t1 and
the pressure p as defined in 2.2.
2.2 The section modulus of stiffeners of detached tanks is not to be less than:
W = c @ a @ R2
@ p @ k [cm3
]
c = 0,36 if stiffeners are constrained at both ends
= 0,54 if one or both ends are simply supported
p = 9,81 @ h [kN/m2
]
h = head measured from the load centre of plate panel or stiffener respectively to the top of overflow; the height
of overflow is not to be taken less than 2,5 m.
2.3 For minimum thickness the requirements of A.7 apply in general.
F. Potable Water Tanks
1. Potablewatertanksshallbeseparatedfromtankscontainingliquidsotherthanpotablewater,ballastwater,distillate
or feed water.
2. In no case sanitary arrangement or corresponding piping are to be fitted directly above the potable water tanks.
3. Manholes arranged in the tank top are to have sills.
4. If pipes carrying liquids other than potable water are to be led through potable water tanks, they are to be fitted
in a pipe tunnel.
5. Air and overflow pipes of potable water tanks are to be separated from pipes of other tanks.
G. Swash Bulkheads
1. The total area of perforation shall not be less than 5% and should not exceed 10% of the total bulkhead area.
2. The plate thickness shall, in general, be equal to the minimum thickness according to A.7. Strengthenings may
be required for load bearing structural parts.
The free lower edge of a wash bulkhead is to be adequately stiffened.
3. The section modulus of the stiffeners and girders is not to be less than W1 as per B.3., however, in lieu of p the
load pd according to Section 4, D.2., but disregarding pv is to be taken.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-189-320.jpg)
![Section 13 - Stem and Sternframe Structures A, B, C 13-1/8
Section 13
Stem and Sternframe Structures
A. Definitions
ReH = minimum nominal upper yield point [N/mm2
] according to Section 2, B.2.
k = material factor according to Section 2, B.2.1, for cast steel k = kr according to Section 14, A.4.2
CR = rudder force [N] according to Section 14, B. 1.
B1 = support force [N] according to Section 14, C.3.
tK = corrosion addition [mm] according to Section 3,K.
aB = spacing of fore-hooks [m]
B. Stem
1. Bar stem
1.1 The cross sectional area of a bar stem below the load waterline is not to be less than:
Ab = 1,25 @ L [cm2
].
1.2 Starting from the load waterline, the sectional area of the bar stem may be reduced towards the upper end
to 0,75 Ab.
2. Plate stem and bulbous bows
2.1 The thickness is not to be less than:
t = (0,6 + 0,4 aB) @ (0,08 L + 6) [mm]
tmax = 25 [mm]
The plate thickness shall not be less than the required thickness according to Section 6, C.2.
The extension R of the stem plate from its trailing edge aftwards shall not be smaller than:
R = 70 @ [mm]
Dimensioning of the stiffening has to be done according to Section 9.
2.2 Starting from 600 mm above the load waterline up to T + co, the thickness may gradually be reduced to 0,8t.
2.3 Plate stems and bulbous bows have to be stiffened by fore-hooks and/or cant frames. In case of large and long
bulbous bows, see Section 9, A.5.3.3.
C. Sternframe
1. General
1.1 Propeller post and rudder post are to be led into the hull in their upper parts and connected to it in a suitable and
efficient manner. In way of the rudder post the shell is to be strengthened according to Section 6, F. Due regard is to be paid
to the design of the aft body, rudder and propeller well in order to minimize the forces excited by the propeller.
1.2 The following value is recommended for the propeller clearance d0,9 related to 0,9 R (see Fig 13.1):
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-191-320.jpg)
![C Section 13 - Stem and Sternframe Structures13-2/8
[m]
R = propeller radius [m]
v0 = ship's speed, see Section 1, H.5. [knot]
n = number of propeller revolutions per minute
D = maximum displacement of ship [ton]
dp = propeller diameter [m]
( = skew angle of the propeller [E], see Fig. 13.2
zB = height of wheelhouse deck above weather deck [m]
xF = distance of deckhouse front bulkhead from aft edge of stern [m], see Fig. 13.1.
Fig. 13.1 - Propeller clearance d0,9 Fig. 13.2 - Skew angle
1.3 For single screw ships, the lower part of the stern frame is to be extended forward by at least 3 times the frame
spacing from fore edge of the boss, for all other ships by 2 times the frame spacing from after edge of the stern frame.
1.4 The stern tube is to be surrounded by the floor plates or, when the ship's shape is too narrow to be stiffened by
internal rings. Where no sole piece is fitted the internal rings may be dispensed with.
1.5 The plate thickness of sterns of welded construction for twin screw vessels shall not be less than:
t = (0,07 L + 5,0) [mm]
tmax = 22 [mm].
2. Propeller post
2.1 The scantlings of rectangular, solid propeller posts are to be determined according to the following formulae:
R = 1,4 L + 90 [mm]
b = 1,6 L + 15 [mm]
Where other sections than rectangular ones are used, their section modulus is not to be less than that resulting from R
and b.
2.2 Thescantlingsofpropeller posts of welded constructionare to be determined according to the followingformulae:
R = 50 [mm]
b = 36 [mm]
t = 2,4 [mm].
2.3 Where the cross sectional configuration is deviating from Fig. 13.3 and for cast steel propeller posts the section
modulus of the cross section related to the longitudinal axis is not to be less than:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-192-320.jpg)
![Section 13 - Stem and Sternframe Structures C 13-3/8
Wx = 1,2 @ L1,5
@ k [cm3
]
Fig. 13.3 Propeller post
Note
With single-screw ships having in the propeller region above the propeller flaring frames of more than " = 75° the thickness
of the shell should not be less than the thickness of the propeller stem. For " # 75° the thickness may be 0,8 t. In no case
the thickness shall be less than the thickness of the side shell according to Section 6.
This recommendation applies for that part of the shell which is bounded by an assumed sphere the centre of which is located
at the top of a propeller blade in the twelve o’clock position and the radius of which is 0,75 @ propeller diameter.
Sufficient stiffening should be arranged, e.g. by floors at each frame and by longitudinal girders.
2.4 The wal l thickness o f the boss in the propeller post in its finished condition is to be at least 60 % of the
breadth b of the propeller post according to 2.1.
2.5 The wall thickness of the boss in propeller posts of welded construction according to 2.2 shall not be less
than 0,9 the wall thickness of the boss according to D.2.
The outer diameter of the sternframe boss, however,shall not belessthantheouterdiameterofthepropellerbossatitsforward
edge.
3. Rudder post and rudder axle
3.1 The section modulus of the rudder post related to the longitudinal axis of the ship is not to be less than:
Wx = CR @ R @ k @ 10-3
[cm3
]
R = unsupported span of the rudder post [m]
Strength calculations for the rudder post, taking into account the flexibility of the sole piece, may be required where due
to its low rigidity in y-direction the sole piece cannot be regarded as an efficient support for the rudder post and, therefore,
additional bending stresses may arise at the upper point of constraint. The bending stress Fb is not to exceed 85 N/mm2
.
3.2 The diameter of a rudder axle of a balanced rudder is not to be less than :
d = 4,2 [mm]
R = length of rudder axle [m], see Fig. 13.4
b = [m]
bl, b2 see Fig. 13.4.
Regarding strength calculations for the rudder axle, respective remarks under 3.1 are to be observed.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-193-320.jpg)
![C Section 13 - Stem and Sternframe Structures13-4/8
Fig. 13.4 Stationary rudder axle
4. Sole piece
4.1 The section modulus of the sole piece related to the z-axis is not to be less than :
Wz = [cm3
]
B1 = See A.
For rudders with two supports the support force is approximately B1= CR/2, when the elasticity of the sole piece is ignored.
x = distance of the respective cross section from the rudder axis [m]
xmin = 0,5 @ R50
xmax = R50
R50 = see Fig. 13.5 and Section 14, C.3.2.
Fig. 13.5 Length R50 of a sole piece
4.2 The section modulus Wz may be reduced by 15% where a rudder post according to 3.1 is fitted.
4.3 The section modulus related to the y-axis is not to be less than:
- where no rudder post or rudder axle is fitted :
Wy =
- where a rudder post or rudder axle is fitted :
Wy =
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-194-320.jpg)
![Section 13 - Stem and Sternframe Structures C 13-5/8
4.4 The sectional area at the location x = R50 is not to be less than:
As = [mm2
].
4.5 The equivalent stress taking into account bending and shear stresses at any location within the length R50 is not
to exceed:
Fv = = [N/mm2
]
Fb = [N/mm2
]
J = [N/mm2
]
5. Rudder horn of semi spade rudders
5.1 The distribution of the bending moment, shear. force and torsional moment is to be determined according to the
following formulae:
– bending moment: Mb = Bl . z [Nm]
Mbmax = Bl . d [Nm]
– shear force: Q = Bl [N]
– torsional moment: MT = Bl . e(z) [Nm]
FordeterminingpreliminaryscantlingstheflexibilityoftherudderhornmaybeignoredandthesupportingforceBl becalculated
according to the following formulae :
Bl = CR [N]
b, c, d, e(z) and z see Fig. 13.6 and 13.7
b result from the position of the centre of gravity of the rudder area.
Fig. 13.6 - Arrangement of bearings of a semi spade rudder
Fig. 13.7 - Loads on the rudder horn
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-195-320.jpg)
![C Section 13 - Stem and Sternframe Structures13-6/8
5.2 The section modulus of the rudder horn in transverse direction related to the horizontal x-axis is at any location
z not to be less than :
Wx = [cm3
]
5.3 At no cross section of the rudder horn the shear stress due to the shear force Q is to exceed the value:
J = [N/mm2
]
The shear stress is to be determined by the following formulae :
J = [N/mm2
]
Ah = effective shear area of the rudder horn in y-direction [mm2
].
5.4 The equivalent stress at any location (z) of the rudder horn shall not exceed the following value :
Fv = # [N/mm2
]
Fb = [N/mm2
]
JT = [N/mm2
]
AT = sectional area [mm2
] enclosed by the rudder horn at the location considered
th = thickness of the rudder horn plating [mm].
5.5 When determining the thickness of the rudder horn plating the provisions of 5.2 - 5.4 are to be complied with.
The thickness is, however, not to be less than :
tmin = 2,4 [mm]
5.6 The rudder horn plating is to be effectively connected to the aft ship structure, e.g. by connecting the plating to
longitudinal girders, in order to achieve a proper transmission of forces, see Fig. 13.8.
5.7 Transverse webs of the rudder horn are to be led into the hull up to the next deck in a sufficient number and shall
be of adequate thickness.
5.8 Strengthened plate floors are to be fitted in line with the transverse webs in order to achieve a sufficient
connection with the hull. The thickness of these plate floors is to be increased by 50% above the Rule values as required
by Section 8.
5.9 The centre line bulkhead (wash-plate) in the afterpeak is to be connected to the rudder horn.
Fig. 13.8 - Rudder horn integration into the aft ship structure
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-196-320.jpg)
![Section 13 - Stem and Sternframe Structures C, D, E 13-7/8
5.10 Where the transition between rudder horn and shell is curved, about 50 % of the required total section modulus
of the rudder horn is to be formed by the webs in a Section A - A located in the centre of the transition zone, i.e. 0,7r above
the beginning of the transition zone. See Fig. 13.9
Fig 13.9 Transition between rudder horn and shell
D. Propeller Brackets
1. The strut axes should intersect in the axis of the propeller shaft a s far as practicable. The struts are to be
extended through the shell plating and are to be attached in an efficient manner to the frames and plate floors respectively.
The construction in way of the shell is to be carried out with special care. In case of welded connection, the struts are to
haveaweldflangeorathickenedpartoraretobeconnectedwiththeshellplatinginanothersuitablemanner.For-strengthening
of the shell in way of struts and shaft bossings, see Section 6, F. The requirements of Section 19, B.4.3 are to be observed.
2. The scantlings of solid struts are to be determined as outlined below depending on shaft diameter d :
thickness : 0,44 d
cross-sectional area in propeller bracket : 0,44 d2
length of boss : see Rules for Machinery Installations, Volume III, Section 4, D.5.2.
wall thickness of boss : 0,25 d.
3. Propeller brackets and shaft bossings of welded construction are to have the same strength as solid ones according
to 2.
4. For single strut propeller bracket a strength analysis according to E.1.2 and a vibration analysis according to E.2.
are to be carried out. Due consideration is to be given to fatigue strength aspects.
Single strut propeller bracket may also be determined as follows:
W = 0.068 d3
I = 0.018 d4
where;
W = section modulus of strut [mm3
]
I = moment inertia of strut [mm4
]
d = required shaft diameter [mm]
Above formulae applies for bracket length, measured from the outside perimeter of the strut bracket or boss is not to exceed
10.6 d. Where this length is exceeded the scantling of the strut has to be increased.
E. Elastic Stern Tube
1. Strength analysis
When determining the scantlings of the stern tube in way of the connection with the hull, the following stresses are to be
proved:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-197-320.jpg)
![A Section 14 - Rudder and Manoeuvring Arrangement14-2/21
the propeller hub.
Cavitation at surface irregularities :
– Grind and polish all welds.
– Avoid changes of profile shape. Often rudders are built with local thickenings (bubbles) and dents to ease fitting of
the rudder shaft. Maximum changes in profile shape should be kept to less than two percent of profile thickness.
Gap cavitation :
– Round out all edges of the part around the gap.
– Gap size should be as small as possible.
– Place gaps outside of the propeller slipstream.
3. Size of rudder area
In order to achieve sufficient manoeuvring capability the size of the movable rudder area A is recommended to be not less
than obtained from the following formula:
A = c1 @ c2 @ c3 @ c4 @ [m2
]
c1 = factor for the ship type:
= 1,0 in general
= 0,9 for bulk carriers and tankers having a displacement of more than 50 000 ton
= 1,7 for tugs and trawlers
c2 = factor for the rudder type:
= 1,0 in general
= 0,9 for semi-spade rudders
= 0,7 for high lift rudders
c3 = factor for the rudder profile:
= 1,0 for NACA-profiles and plate rudder
= 0,8 for hollow profiles and mixed profiles
c4 = factor for the rudder arrangement:
= 1,0 for rudders in the propeller jet
= 1,5 for rudders outside the propeller jet
For semi-spade rudder 50% of the projected area of the rudder horn may be included into the rudder area A.
Where more than one rudder is arranged the area of each rudder can be reduced by 20 %.
Estimating the rudder area A, B.1. is to be observed.
4. Materials
4.1 For materials for rudder stock, pintles, coupling bolts etc. see Rules for Material Volume V. Special material
requirements are to be observed for the ice Class Notations ES3 and ES4 as well as for the ice Class Notations PC7 -
PC1.
4.2 In general materials having a minimum nominal upper yield point ReH of less than 200 N/mm2
and a minimum
tensile strength of less than 400 N/mm2
or more than 900 N/mm2
shall not be used for rudder stocks, pintles, keys and
bolts. The requirements of this Section are based on a material's minimum nominal upper yield point ReH of 235 N/mm2
.
If material is used having a ReH differing from 235 N/mm2
, the material factor kr is to be determined as follows :
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-200-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement A 14-3/21
kr = for ReH > 235 [N/mm2
]
= for ReH 235 [N/mm2
]
ReH = minimum nominal upper yield point of material used [N/mm2
].
ReH is not to be taken greater than 0,7. Rm or 450 N/mm2
, whichever is less. Rm = tensile strength of the material
used.
4.3 Before significant reductions in rudder stock diameter due to the application of steels with ReH exceeding
235 N/mm2
are granted, BKI may require the evaluation of the elastic rudder stock deflections. Large deflections should
be avoided in order to avoid excessive edge pressures in way of bearings.
4.4 The permissible stresses given in E.1. are applicable for normal strength hull structural steel. When higher tensile
steels are used, higher values may be used which will be fixed in each individual case.
5. Definitions
CR = rudder force [N]
QR = rudder torque [Nm]
A = total movable area of the rudder [m2
], measured at the mid-plane of the rudder
For nozzle rudders, A is not to be taken less than 1,35 times the projected area of the nozzle.
At = A + area of a rudder horn, if any, [m2
]
Af = portion of rudder area located ahead of the rudder stock axis [m2
]
b = mean height of rudder area [m]
c = mean breadth of rudder area [m] (see Fig. 14.1a)
Fig. 14.1a Rudder area geometry
7 = aspect ratio of rudder area At
=
v0 = ahead speed of ship [kn] as defined in Section.1, H.5.; if this speed is less than 10 kn, v0 is to be taken as
[kn]
va = astern speed of ship [kn]; if the astern speed va < 0,4 @ v0 or 6 kn, whichever is less, determination of rudder
force and torque for astern condition is not required. For greater astern speeds special evaluation of rudder
force and torque as a function of the rudder angle may be required. If no limitations for the rudder angle at
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-201-320.jpg)
![A,B Section 14 - Rudder and Manoeuvring Arrangement14-4/21
astern condition is stipulated, the factor 62 is not to be taken less than given in Table 14.1forasterncondition.
k = material factor according to Section 2, B.2.
For ships strengthened for navigation in ice, Section 15, B.9 and D.3.7 have to be observed.
B. Rudder Force and Torque
1. Rudder force and torque for normal rudders
1.1 The rudder force is to be determined according to the following formula:
CR = 132 @ A @ v2
@ 61 @ 62 @ 63 @ 6t [N]
v = v0 for ahead condition
= va for astern condition
61 = coefficient, depending on the aspect ratio 7
= (7 + 2)/3, where 7 need not be taken greater than 2
62 = coefficient, depending on the type of the rudder and the rudder profile according to Table 14.1.
63 = coefficient, depending on the location of the rudder
= 0,8 for rudders outside the propeller jet
= 1,0 elsewhere, including also rudders within the propeller jet
= 1,15 for rudders aft of the propeller nozzle
6t = coefficient depending on the thrust coefficient CTh
= 1,0 normally
In special cases for thrust coefficients CTh > 1,0 determination of 6t according to the following formula may be required:
6t =
1.2 The rudder torque is to be determined by the following formula:
QR = CR @ r [Nm]
r = c (" n kb) [m]
" = 0,33 for ahead condition
= 0,66 for astern condition (general)
= 0,75 for astern condition (hollow profiles)
For parts of a rudder behind a fixed structure such as a rudder horn:
" = 0,25 for ahead condition
= 0,55 for astern condition.
For high lift rudders " is to be specially considered. If not known, " = 0,4 may be used for the ahead condition.
kb = balance factor as follows:
=
= 0,08 for unbalanced rudders
rmin = 0,1 @ c [m] for ahead condition.
1.3 Effects of the provided type of rudder / profile on choice and operation of the steering gear are to be observed.
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-202-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement B 14-5/21
2. Rudder force and torque for rudder blades with cut-outs (semi-spade rudders)
2.1 The total rudder force CR is to be calculated according to 1.1. The pressure distribution over the rudder area, upon
which the determination of rudder torque and rudder blade strength is to be based, is to be derived as follows :
The rudder area may be divided into two rectangular or trapezoidal parts with areas A1 and A2 (see Fig. 14.2).
Table 14.1 - Coefficient 62
Profile Type
62
Ahead Condition Astern Condition
for Ordinary Rudders
1
Single plate
1.0 1.0
2
NACA-OO
Göttingen
1.1 0.80
3
Flat Side
1.1 0.90
4
Mixed
(e.g., HSVA)
1.21 0.90
5
Hollow
1.35 0.90
for High-Lift/Performance Rudders
6
Fish tail
(e.g., Schilling high-lift rudder)
1.4 0.8
7
Flap rudder
1.7 1.3
8
Rudder with steering nozzle
1.9 1.5
The resulting force of each part may be taken as:
CR1 = CR [N]
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-203-320.jpg)
![B, C Section 14 - Rudder and Manoeuvring Arrangement14-6/21
CR2 = CR [N]
2.2 The resulting torque of each part may be taken as:
QR1 = CR1 @ r1 [Nm]
QR2 = CR2 @ r2 [Nm]
The levers r1 and r2 are to be determined as follows :
r1 = c1 (" n kbl) [m]
r2 = c2 (" n kb2) [m]
kb1 =
kb2 =
A1f, A2f see Fig. 14.2
c1 =
c2 =
b1, b2 = mean heights of the partial rudder areas A1 and A2 (see Fig. 14.2).
Fig. 14.2 Partial area A1 and A2
2.3 The total rudder torque is to be determined according to the following formulae:
QR = QR1 + QR2 [Nm] or
QRmin = CR @ r1,2min [Nm]
r1,2min = ( c1 @ A1 + c2 @ A2 ) [m] for ahead condition
The greater value is to be taken.
C. Scantlings of the Rudder Stock
1. Rudder stock diameter
1.1 The diameter of the rudder stock for transmitting the torsional moment is not to be less than :
Dt = 4,2 [mm]
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-204-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement C 14-7/21
QR see B. 1.2 and B. 2.2 - 2.3.
The related torsional stress is:
Jt = [N/mm2
]
kr see A.4.2.
1.2 The steering gear is to be determined according to Rules for Machinery Installations, Volume III, Section 14 for
theruddertorque QR as required in B.1.2, B.2.2 or B.2.3 and under considerationofthefrictionallossesattherudderbearings.
1.3 In case of mechanical steering gear the diameter of the rudder stock in its upper part which is only intended for
transmission of the torsional moment fromthe auxiliary steering gear may be 0,9 Dt. The length of the edge of the quadrangle
for the auxiliary tiller shall not be less than 0,77 Dt and the height not less than 0,8 Dt.
1.4 The rudder stock is to be secured against axial sliding. The degree of the permissible axial clearance depends on
the construction of the steering engine and on the bearing.
2. Strengthening of rudder stock
If the rudder is so arranged that additional bending stresses occur in the rudder stock, the stock diameter has to be suitably
increased. The increased diameter is, where applicable, decisive for the scantlings of the coupling.
For the increased rudder stock diameter the equivalent stress of bending and torsion is not to exceed the following value:
Fv = = [N/mm2
]
Bending stress:
Fb = [N/mm2
]
Mb = bending moment at the neck bearing [Nm]
Torsional stress:
J = [N/mm2
]
D1 = increased rudder stock diameter [mm]
The increased rudder stock diameter may be determined by the following formula:
D1 = Dt [mm]
QR see B.1.2 and B.2.2 - 2.3
Dt see 1.1.
Note
Where a double-piston steering gear is fitted, additional bending moments may be transmitted from the steering gear into
the rudder stock. These additional bending moments are to be taken into account for determining the rudder stock diameter.
3. Analysis
3.1 General
The evaluation of bending moments, shear forces and support forces for the system rudder - rudder stock may be carried
out for some basic rudder types as shown in Figs. 14.3 - 14.5 as outlined in 3.2. - 3.3.
3.2 Data for the analysis
R10 n R40 = lengths of the individual girders of the system [m]
I10 n I40 = moments of inertia of these girders [cm4
]
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-205-320.jpg)
![C Section 14 - Rudder and Manoeuvring Arrangement14-8/21
For rudders supported by a sole piece the length R20 is the distance between lower edge of rudder body and centre of sole
piece, and I20 is the moment of inertia of the pintle in the sole piece.
Load on rudder body (general):
pR = [kN/m]
Load on semi-spade rudders:
pR10 = [kN/m]
pR20 = [kN/m]
CR, CR1, CR2 see B.1. and B.2.
Z = spring constant of support in the sole piece or rudder horn respectively
for the support in the sole piece (Fig. 14.3) :
Z = [kN/m]
for the support in the rudder horn (Fig. 14.4) :
Z = [kN/m]
fb = unit displacement of rudder horn [m] due to a unit force of 1 kN acting in the centre of support
fb = 0,21 [m/kN] (guidance value for steel)
In = moment of inertia of rudder horn around the x-axis at d/2 [cm4
] (see also Fig. 14.4)
ft = unit displacement due to torsional moment of the amount 1 @ e [kNm]
=
= [m/kN] for steel
G = modulus of rigity
= 7,92 @ 107
[kN/m2
] for steel
Jt = torsional moment of inertia [m4
]
FT = mean sectional area of rudder horn [m2
]
ui = breadth [mm] of the individual plates forming the mean horn sectional area
ti = plate thickness within the individual breadth ui [mm]
e, d = distances [m] according to Fig. 14.4.
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-206-320.jpg)
![C Section 14 - Rudder and Manoeuvring Arrangement14-10/21
Fig. 14.5 Spade rudder
Fig. 14.6 - Spade rudders with rudder trunks inside the rudder body
3.3 Moments and forces to be evaluated
3.3.1 The bending moment MR and the shear force Ql in the rudder body, the bending moment Mb in the neck bearing
and the support forces Bl, B2, B3 are to be evaluated.
The so evaluated moments and forces are to be used for the stress analyses required by 2. and E.1. of this Section and by
Section 13, C.4. and C.5.
3.3.2. For spade rudders the moments and forces may be determined by the following formulae:
Mb = CR [Nm]
B3 = [N]
B2 = CR + B3 [N]
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-208-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement C 14-11/21
3.3.3 For spade rudders with rudder trunks (seeFig.14.6)themomentsandforcesmaybedeterminedbythe following
formulae:
CR1 = rudder force over the partial rudder area A1 according to B.2.1 [N]
CR2 = rudder force over the partial rudder area A2 according to B.2.1 [N]
MCR1 = [Nm]
MCR2 = [Nm]
MR = Max (MCR1, MCR2) [Nm]
Mb = MCR2 - MCR1 [Nm]
B3 = [N]
B2 = CR + B3 [N]
4. Rudder trunk
4.1 In case where the rudder stock is fitted with a rudder trunk welded in such a way the rudder trunk is loaded by
thepressureinducedontherudderblade,asgiveninB.1.1,thebendingstressintheruddertrunk,inN/mm2
,istobeincompliance
with the following formula :
F < 80 / k
where the material factor k for the rudder trunk is not to be taken less than 0,7.
For the calculation of the bending stress, the span to be considered is the distance between the mid-height of the lower rudder
stock bearing and the point where the trunk is clamped into the shell or the bottom of the skeg.
4.2 The weld at the connection between the rudder trunk and the shellorthebottomoftheskegistobefullpenetration.
The fillet shoulder radius r, in mm, is to be as large as practicable and to comply with the following formulae:
r = 60 when F $ 40 / k [N/mm2
]
r = 0,1 D1 when F < 40 / k [N/mm2
]
without being less than 30, where D1 is defined in 2.1.
Note
The radius may be obtained by grinding. If disk grinding is carried out, score marks are to be avoided in the direction of
the weld.
The radius is to be checked with a template for accuracy. Four profiles at least are to be checked. A report is to be submitted
to the Surveyor.
Before welding is started, a detailedweldingprocedurespecificationistobesubmittedto BKIcovering the weld preparation,
weldingpositions,weldingparameters,weldingconsumables,preheating,postweldheattreatmentandinspectionprocedures.
This welding procedure is to be supported by approval tests in accordance with the applicable requirements of materials
and welding sections of the rules.
The manufacturer is to maintain records of welding, subsequentheat treatment and inspections traceable to the welds. These
records are to be submitted to the Surveyor.
Non destructive tests are to be conducted at least 24 hours after completion of the welding. The welds are to be 100
% magnetic particle tested and 100 % ultrasonic tested.
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-209-320.jpg)
![D Section 14 - Rudder and Manoeuvring Arrangement14-12/21
D. Rudder Couplings
1. General
1.1 The couplings are to be designed in such a way as to enable them to transmit the full torque of the rudder stock.
1.2 The distance of bolt axis fromthe edges of the flange is notto be less than 1,2 the diameter of the bolt. In horizontal
couplings, at least 2 bolts are to be arranged forward of the stock axis.
1.3 The coupling bolts are to be fitted bolts. The bolts and nuts are to be effectively secured against loosening, e.g.
according to recognized standards.
1.4 For spade rudders horizontal couplings according to 2. are permissible only where the required thickness of the
coupling flanges tf is less than 50 mm, otherwise cone couplings according to 4. are to be applied. For spade rudders of the
high lift type, only cone couplings according to 4. are permitted.
2. Horizontal couplings
2.1 The diameter of coupling bolts is not to be less than :
db = 0,62 [mm]
D = rudder stock diameter according to C. [mm]
n = total number of bolts, which is not to be less than 6
e = mean distance of the bolt axes from the centre of bolt system [mm]
kr = material factor for the rudder stock as given in A.4.2
kb = material factor for the bolts analogue to A.4.2.
2.2 The thickness of the coupling flanges is not to be less than determined by the following formulae:
tf = 0,62 [mm]
tfmin = 0,9 @ db
kf = material factor for the coupling flanges analogue to A.4.2.
The thickness of the coupling flanges clear of the bolt holes is not to be less than 0,65 @ tf.
The width of material outside the bolt holes is not to be less than 0,67 @ db.
2.3 ThecouplingflangesaretobeequippedwithafittedkeyaccordingtoDIN6885orequivalentstandardsforrelieving
the bolts.
The fitted key may be dispensed with if the diameter of the bolts is increased by 10%.
2.4 Horizontal coupling flanges should either be forged togetherwith the rudder stock or be weldedtotherudderstock
as outlined in Section 19, B.4.4.3.
2.5 For the connection of the coupling flanges with the rudder body see also Section 19, B.4.4.
3. Vertical couplings
3.1 The diameter of the coupling bolts is not to be less than :
db = [mm]
D, kb, kr, n see 2.1, where n is not to be less than 8.
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-210-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement D 14-13/21
3.2 The first moment of area of the bolts about the centre of the coupling is not to be less than :
S = 0,00043 D3
[cm3
].
3.3 The thickness of the coupling flanges is not to be less than :
tf = db [mm]
The width of material outside the bolt holes is not to be less than 0,67 @ db.
4. Cone couplings
4.1 Cone couplings with key
4.1.1 Cone couplings should have a taper c on diameter of 1: 8 - 1:12.
c = according Fig. 14.7.
The cone shapes should fit very exact. The nut is to be carefully secured, e.g. by securing plate as shown in Fig. 14.7.
Fig. 14.7 - Cone coupling with key and securing plate
4.1.2The coupling length R shall, in general. not be less than 1,5 @ d0.
4.1.3For couplings between stock and rudder a key is to be provided, the shear area of which is not to be less than:
as = [cm2
]
QF = design yield moment of rudder stock [Nm] according to F.
dk = diameter of the conical part of the rudder stock [mm] at the key
ReHl = minimum nominal upper yield point of the key material [N/mm2
]
4.1.4The effective surface area of the key (without rounded edges) between key and rudder stock or cone coupling, is not
to be less than:
ak = [cm2
]
ReH2 = minimum nominal upper yield point of the key, stock or coupling material [N/mm2
], whichever is less.
4.1.5The dimensions of the slugging nut are to be as follows, see Fig. 14.7:
– height:
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-211-320.jpg)
![D Section 14 - Rudder and Manoeuvring Arrangement14-14/21
hn = 0,6 @ dg
– outer diameter (the greater value to be taken):
dn = 1,2 @ du or dn = 1,5 @ dg
– external thread diameter:
dg = 0,65 @ d0
4.1.6It is to be proved that 50% of the design yield moment will be solely transmitted by friction in the cone couplings. This
can be done by calculating the required push-up pressure and push-up length according to 4.2.3 for a torsional moment Q'F
= 0,5 @ QF
4.2 Cone couplings with special arrangements for mounting and dismounting the couplings
4.2.1Wherethestockdiameterexceeds200mmthepressfitisrecommendedtobeeffectedbyahydraulicpressureconnection.
In such cases the cone should be more slender, c . 1:12 to . 1 : 20.
4.2.2In case of hydraulic pressure connections the nut is to be effectively secured against the rudder stock or the pintle. A
securing plate for securing the nut against the rudder body is not to be provided, see Fig. 14.8.
Fig. 14.8 - Cone coupling without key and with securing flat bar
Note
A securing flat bar will be regarded as an effective securing device of the nut, if its shear area is not less than:
As = [ mm2
]
Ps = shear force as follows
= [N]
Pe = push-up force according to 4.2.3.2 [N]
µ1 = frictional coefficient between nut and rudder body, normally µ1 = 0,3
d1 = mean diameter of the frictional area between nut and rudder body, see Fig. 14.8
dg = thread diameter of the nut
ReH = yield point [N/mm²] of the securing flat bar material.
4.2.3For the safe transmission of the torsional moment by the coupling between rudder stock and rudder body the push-up
length and the push-up pressure are to be determined by the following formulae.
4.2.3.1 Push-up pressure
The push-up pressure is not to be less than the greater of the two following values :
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-212-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement D 14-15/21
preq1 = [N/mm2
]
preq2 = [N/mm2
]
QF = design yield moment of rudder stock according to F. [Nm]
dm = mean cone diameter [mm]
R = cone length [mm]
:0 . 0,15 (frictional coefficient)
Mb = bending moment in the cone coupling (e.g. in case of spade rudders) [Nm].
It has to be proved that the push-up pressure does not exceed the permissible surface pressure in the cone. The permissible
surface pressure is to be determined by the following formula :
pperm = [N/mm2
]
ReH = yield point [N/mm2
] of the material of the gudgeon
" = dm /da (see Fig 14.7)
The outer diameter of the gudgeon shall not be less than:
da = 1,5 @ dm [mm]
4.2.3.2 Push-up length
The push-up length is not to be less than:
)R1 = [mm]
Rtm = mean roughness [mm]
• 0,01 mm
c = taper on diameter according to 4.2.1
E = Young's modulus (2,06 @ 105
N/mm2
)
A guidance figure for the minimum push-up length is :
)Rmin= [mm]
The push-up length is, however, not to be taken greater than :
)R2 = [mm]
Note
In case of hydraulic pressure connections the required push-up force Pe for the cone may be determined by the following
formula :
Pe = [N]
The value 0,02 in above formula is a reference value for the friction coefficient using oil pressure. It varies and depends
on the mechanical treatment and roughness of the details to be fixed.
Whereduetothefittingprocedureapartialpush-upeffectcaused bythe rudder weightis given,thismaybetakenintoaccount
when fixing the required push-up length, subject to approval by BKI.
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![D, E Section 14 - Rudder and Manoeuvring Arrangement14-16/21
4.2.4The required push-up pressure for pintle bearings is to be determined by the following formula :
preq = 0,4 [N/mm2
]
Bl = supporting force in the pintle bearing [N], see also Fig. 14.4
dm, R = see 4.2.3
d0 = pintle diameter [mm] according to Fig. 14.7.
E. Rudder Body, Rudder Bearings
1. Strength of rudder body
1.1 The rudder body is to be stiffened by horizontal and vertical webs in such a manner that the rudder body will be
effective as a beam. The rudder should be additionally stiffened at the aft edge.
1.2 The strength of the rudder body is to be proved by direct calculation according to C.3.
1.3 For rudder bodies without cut-outs the permissible stress are limited to :
bending stress due to MR:
Fb = 1l0 [N/mm2
]
shear stress due to Ql:
J = 50 [N/mm2
]
equivalent stress due to bending and shear:
Fv = = 120 [N/mm2
]
MR, Q1 see C.3.3.and Fig.14.3 and 14.4.
In case of openings in the rudder plating for access to cone coupling or pintle nut the permissible stresses according to 1.4
apply.Smallerpermissiblestressvaluesmayberequiredifthecornerradiiarelessthan 0,15@ ho, where ho = heightofopening.
1.4 In rudder bodies with cut-outs (semi-spade rudders) the following stress values are not to be exceeded :
bending stress due to MR :
Fb = 90 [N/mm2
]
shear stress due to Ql :
J = 50 [N/mm2
]
torsional stress due to Mt :
Jt = 50 [N/mm2
]
equivalent stress due to bending and shear and equivalent stress due to bending and torsion:
Fv1 = = 120 [N/mm2
]
Fv2 = = 100 [N/mm2
]
MR = CR2 @ fl + B1 [Nm]
Q1 = CR2 [N]
f1, f2 see Fig. 14.9.
The torsional stress may be calculated in a simplified manner as follows :
Jt = [N/mm2
]
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-214-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement E 14-17/21
Mt = CR2 @ e [Nm]
CR2 = partial rudder force [N] of the partial rudder area A2 below the cross section under consideration
e = lever for torsional moment [m]
(horizontal distance between the center of pressure of area A2 and the centre line a-a of the effective cross
sectional area under consideration, see Fig. 14.9. The center of pressure is to be assumed at 0,33 @ c2 aft
of the forward edge of area A2, where c2 = mean breadth of area A2)
h, R, t [cm], see Fig. 14.9.
Fig. 14.9 Geometry of semi-spade rudder
The distance R between the vertical webs should not exceed 1,2 @ h.
The radii in the rudder plating are not to be less than 4 - 5 times the plate thickness, but in no case less than 50 mm.
Note
It is recommended to keep the natural frequency of the fully immersed rudder and of local structural components at least
10% above the exciting frequency of the propeller (number of revolutions x number of blades) or if relevant, above higher
order.
2. Rudder plating
2.1 Double plate rudders
2.1.1The thickness of the rudder plating is to be determined according to the following formula:
t = [mm]
PR = 10 @ T + [kN/m2
]
a = the smaller unsupported width of a plate panel [m].
The influence of the aspect ratio of the plate panels may be taken into account as given in Section 3, A.3.
The thickness shall, however, not be less than the thickness tmin according to Section 6, B.3.1.
To avoid resonant vibration of single plate fields the frequency criterion as defined in Section 12, A.8.3 (" < 60°)
for shell structures applies analogously.
Regarding dimensions and welding Section 19, B.4.4.1 has to be observed in addition.
2.1.2For connecting the side plating of the rudder to the webs tenon welding is not to be used. Where application of fillet
welding is not practicable, the side plating is to be connected by means of slot welding to flat bars which are welded to the
webs.
2.1.3The thickness of the webs is not to be less than 70% of the thickness of the rudder plating according to 2.1.1, but not
less than:
tmin = 8 [mm]
Webs exposed to seawater must be dimensioned according to 2.1.1.
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-215-320.jpg)
![E Section 14 - Rudder and Manoeuvring Arrangement14-18/21
2.2 Single plate rudders
2.2.1 Main piece diameter
The main piece diameter is calculated according to C.1 and C.2 respectively. For spade rudders the lower third may taper
down to 0.75 times stock diameter.
2.2.2Blade thickness
2.2.2.1 The blade thickness is not to be less than:
tb = [mm]
a = spacing of stiffening arms [m], not to exceed 1 m;
v0 = ahead speed of ship [kn]
2.2.2.2 After edge of rudder plating to be rounded.
2.2.3Arms
The thickness of the arms “ t a” is not to be less than the blade thickness according to 2.2.2.
The section modulus is to be determined as follow:
Wa = [cm3
]
c1 = horizontal distance from the aft edge of the rudder to the centreline of the rudder stock [m].
3. Transmitting of the rudder torque
3.1 For transmitting the rudder torque, the rudder plating according to 2.1.1 and 2.2.2.1 is to be increased by 25%
in way of the coupling. A sufficient number of vertical webs is to be fitted in way of the coupling.
3.2 If the torque is transmitted by a prolonged shaft extended into the rudder, the latter shall have the diameter Dt
or D1, whichever is greater, at the upper 10% of the intersection length. Downwards it may be tapered to 0,6 Dt, in spade
rudders to 0,4 times the strengthened diameter, if sufficient support is provided for.
4. Rudder bearings
4.1 In way of bearings liners and bushes are to be fitted. Their minimum thickness is
tmin = 8 mm for metallic materials and synthetic material
= 22 mm for lignum material
Where in case of small ships bushes are not fitted, the rudder stock is to be suitably increased in diameter in way of bearings
enabling the stock to be re-machined later.
4.2 An adequate lubrication is to be provided.
4.3 The bearing forces result from the direct calculation mentioned in C.3. As a first approximation the bearing force
may be determined without taking account of the elastic supports. This can be done as follows:
– normal rudder with two supports:
The rudder force CR is to be distributed to the supports according to their vertical distances from the centre of
gravity of the rudder area.
– semi-spade rudders:
S support force in the rudder horn:
B1 = CR @ [N]
S support force in the neck bearing:
B2 = CR - Bl [N]
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-216-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement E 14-19/21
For b and c see Section 13, Fig. 13.6.
4.4 The projected bearing surface Ab (bearing height x external diameter of liner) is not to be less than
Ab = [mm2
]
B = support force [N]
q = permissible surface pressure according to Table 14.2
Table 14.2 - Permissible surface pressure q
Bearing material q [N/mm2
]
lignum vitae 2,5
white metal, oil lubricated 4,5
synthetic material1)
5,5
steel2)
, bronze and hot-pressed bronze-graphite
materials
7,0
1)
Synthetic materials to be of approved type.
Surfacepressuresexceeding5,5N/mm²maybeacceptedinaccordancewithbearing
manufacturer's specification and tests, but in no case more than 10 N/mm².
2)
Stainlessandwearresistantsteelinanapprovedcombinationwithstockliner.Higher
surface pressures than7 N/mm² may be accepted if verified by tests.
4.5 Stainlessandwearresistantsteels,bronzeandhot-pressedbronze-graphitematerialshaveaconsiderabledifference
in potential to non-alloyed steel. Respective preventive measures are required.
4.6 The bearingheightshallbeequalto the bearing diameter, however, is not to exceed 1,2 times the bearing diameter.
Where the bearing depth is less than the bearing diameter, higher specific surface pressures may be allowed.
4.7 The wallthickness ofpintle bearingsinsolepieceandrudderhornshallbeapproximately¼of the pintle diameter.
5. Pintles
5.1 Pintles are to have scantlings complying with the conditions given in 4.4 and 4.6. The pintle diameter is not to
be less than:
d = 0,35 [mm]
Bl = support force [N]
kr = see A.4.2.
5.2 The thickness of any liner or bush shall not be less than:
t = 0,01 [mm]
or the values in 4.1 respectively.
5.3 Where pintles are of conical shape, they are to comply with the following:
taper on diameter 1: 8 to 1: 12 if keyed by slugging nut,
taper on diameter 1: 12 to 1: 20 if mounted with oil injection and hydraulic nut.
5.4 The pintles are to be arranged in such a manner as to prevent unintentional loosening and falling out.
For nuts and threads the requirements of D.4.1.5 and 4.2.2 apply accordingly.
6. Guidance values for bearing clearances
6.1 For metallic bearing material the bearing clearance shall generally not be less than:
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![E, F, G, H Section 14 - Rudder and Manoeuvring Arrangement14-20/21
[mm]
db = inner diameter of bush.
6.2 If non-metallic bearing material is applied, the bearing clearance is to be specially determined considering the
material's swelling and thermal expansion properties and to be in accordance with maker recommendation.
6.3 The clearance is not to be taken less than 1,5 mmon diameter. In case of self lubricating bushes going down below
this value can be agreed to on the basis of the manufacturer's specification.
F. Design Yield Moment of Rudder Stock
The design yield moment of the rudder stock is to be determined by the following formula:
QF = 0,02664 [Nm]
Dt = stock diameter [mm] according to C.1.
Where the actual diameter Dta is greater than the calculated diameter Dt, the diameter Dta is to be used. However, Dta need
not be taken greater than 1,145 . Dt.
G. Stopper, Locking Device
1. Stopper
The motions of quadrants or tillers are to be limited on either side by stoppers. The stoppers and their foundations connected
to the ship's hull are to be of strong construction so that the yield point of the applied materials is not exceeded at the design
yield moment of the rudder stock.
2. Locking device
Each steering gear is to be provided with a locking device in order to keep the rudder fixed at any position. This device as
well as the foundation in the ship's hull are to be of strong construction so that the yield point of the applied materials is not
exceeded at the design yield moment of the rudder stock as specified in F. Where the ship's speed exceeds 12 kn, the design
yield moment need only be calculated for a stock diameter based on a speed v0 = 12 [kn].
3. Regarding stopper and locking device see also Rules for Machinery Installations, Volume III, Section.14.
H. Propeller Nozzles
1. General
1.1 The following requirements are applicable to propeller nozzles having an inner diameter of up to 5 m. Nozzles
with larger diameters will be specially considered.
1.2 Special attention is to be given to the support of fixed nozzles at the hull structure.
2. Design pressure
The design pressure for propeller nozzles is to be determined by the following formula :
pd = [kN/m2
]
pdo = g [kN/m2
]
N = maximum shaft power [kW]
BKI - Rules for Hull - 2013](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-218-320.jpg)
![Section 14 - Rudder and Manoeuvring Arrangement H 14-21/21
Ap = propeller disc area [m2
]
=
D = propeller diameter [m]
g = factor according to the following formula:
g = 0,21 n 2 @ 10-4
gmin = 0,10
c = 1,0 in zone 2 (propeller zone),
= 0,5 in zones 1 and 3
= 0,35 in zone 4.
see Fig. 14.10
Fig. 14.10 Zone 1 to 4 of propeller nozzle
3. Plate thickness
3.1 The thickness of the nozzle shell plating is not to be less than:
t = 5 @ + tK [mm]
tmin = 7,5 [mm]
a = spacing of ring stiffeners [m].
3.2 The web thickness of the internal stiffening rings shall not be less than the nozzle plating for zone 3, however,
in no case be less than 7,5 mm.
4. Section modulus
The section modulus of the cross section shown in Fig. 14.10 around its neutral axis is not to be less than:
W = n @ d2
@ b @ v0
2
[cm3
]
d = inner diameter of nozzle [m]
b = length of nozzle [m]
n = 1,0 for rudder nozzles
= 0,7 for fixed nozzles.
5. Welding
Theinnerandouternozzleshellplatingistobeweldedtotheinternalstiffeningringsasfaraspracticablebydoublecontinuous
welds. Plug welding is only permissible for the outer nozzle plating.
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![A Section 15 - Strengthening for Navigation in Ice15-2/17
Upon request, the Notation ES may be assigned independently for hull or machinery.
1.6 Ships which beyond the requirements for the ice Class Notations ES, ES1 to ES4 or PC7 to PC1 have been
specially designed, dimensioned and/or equippedforicebreakingwillhaveaffixedthenotationICEBREAKER in addition.
Dimensioning of the structure with regard to the foreseen area of operation has to be harmonized with BKI.
1.7 Ships intended for navigation in arctic waters may have the ice Class Notations PC7 - PC1 affixed to their
Character of Classification if the requirements given in Guidelines for the Construction of Polar Class Ships are complied
with.
1.8 If the scantlings required by this Section are less than those required for ships without ice strengthening, the
scantlings required by the other Sections of these Rules are to be maintained.
2. Ice class draught for Ships with Notations ES1-ES4
2.1 The upper ice waterline (UIWL) is to be the highest waterline at which the ship is intended to operate in ice. The
lower ice waterline (LIWL) is to be the lowest waterline at which the ship is intended to operate in ice. Both the UIWL and
LIWL may be broken lines.
2.2 The maximum and minimum ice class draughts at the forward perpendicular, amidships and at the aft
perpendicular are to be determined in accordance with the upper/lower ice waterlines and are to be stated in the drawings
submitted for approval. The maximum ice class draught at the forward perpendicular is not to be less than the maximum
draught at amidships. The ice class draughts, the minimum propulsion machinery output, P, according to 3., as well as the
corresponding ice class, will be stated in the Annex to the Class Certificate.
If the summer load line in fresh water is located at a higher level than the UIWL, the ship's sides are to be provided with
a warning triangle and with an ice class draught mark at the maximum permissible ice class draught amidships (see Annex
B).
2.3 The draught and trim, limited by the UIWL,shall not be exceeded when the ship is navigating in ice. The salinity
of the sea water along the intended route is to be taken into account when loading the ship.
The ship is always to be loaded down at least to the LIWL when navigating in ice. The LIWL is to be agreed upon with
the owners. For ships with the ice class notations E1 – E4, any ballast tank adjacent to the side shell and situated above the
LIWL, and needed to load the ship down to this waterline, is to be equipped with devices to prevent the water from freezing.
In determining the LIWL, regard is to be paid to the need for ensuring a reasonable degree of ice-going capability in ballast.
The propeller is to be fully submerged, entirely below the ice, if possible.
2.4 For ships with the ice class notations ES1 - ES4 the minimum draught at the forward perpendicular shall not be
less than the smaller of the following values :
Tmin = h0 (2 + 2,5 @ 10-4
@ D) [m]
or
Tmin = 4 @ h0 [m]
D = displacement of the ship [t] on the maximum ice class draught according to 2.1
h0 = design ice thickness according to B.2.1.
3. Propulsion machinery output for ships with Notations ES1-ES4
3.1 The propulsion machinery output P in the context of this Section, is the total maximum output the propulsion
machinery can continuously deliver to the propeller(s). If the output of the machinery is restricted by technical means or by
any regulations applicable to the ship, P is to be taken as the restricted output.
3.2 For ships with the ice class notation ES1 or ES2, the keels of which were laid or which are in a similar stage of
construction before September 1st
, 2003, the propulsion machinery output is not to be less than:
P = f1 @ f2 @ f3 (f4 @ D + P0) [kW]
Pmin = 740 kW
f1 = 1,0 for a fixed pitch propeller
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![Section 15 - Strengthening for Navigation in Ice A 15-3/17
= 0,9 for a controllable pitch propeller
f2 = + 0,675, but not more than 1,1
= 1,1 for a bulbous bow
f1 @ f2 > 0,85
n1 = the forward facing angle between the stem and the UIWL. If the stem forms a fair curve within the ice belt
as defined in 4.1 it may be presented by a straight line between the points of intersection of the stem and
the upper and lower limits of the ice belt. If there are sharp changes in the inclination of the stem the largest
n1 is to be used.
f3 = 1,2 , but not less than 1,0
f4 and Po are to be taken from Table 15.1 for the respective ice Class Notation and displacement.
Table 15.1 - Factor f4 and power P0 for the determination of minimum propulsion machinery output for ships of
ice classes ES1 and ES2
Ice class notation ES2 ES1 ES2 ES1
D [t] < 30 000 $ 30 000
f4 0,22 0,18 0,13 0,11
P0 370 0 3070 2100
D = displacement of the ship [t] as per 2.4.D need not to be taken as greater than 80 000 t.
For ES2, no higher propulsion machinery output, P, than required for ES3 is necessary.
Note
The Finnish Administration may in special cases approve an propulsion machinery output below that required in
accordance with 3.2 above.
3.3 For ships with the ice Class Notation ES1 or ES2, the keels of which are laid or which are in a similar stage of
construction on or after September 1st
, 2003, and for ships with the ice class notation ES3 or ES4, the propulsion machinery
output is not to be less than :
P = [kW]
Pmin = 2800 kW for ice class notation ES4
= 1000 kW for ice class notation ES1, ES2 and ES3
The required propulsion machinery output P is to be calculated for ships on both the UIWL and the LIWL. The propulsion
machinery output shall not be less than the greater of these two outputs.
Ke = is be taken from Table 15.2
The values in Table 15.2 apply only to conventional propulsion systems. Other methods may be used for determining the
Ke values for advanced propulsion systems as specified in 3.4.
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![A Section 15 - Strengthening for Navigation in Ice15-4/17
Table 15.2 Factor Ke for the determinationofminimumpropulsionmachinery output for ships of ice classes ES3
and ES4
Propeller type or machinery
Ke
CP or electric or hydraulic
propulsion machinery
FP propeller
1 propeller 2,03 2,26
2 propellers 1,44 1,60
3 propellers 1,18 1,31
DP = diameter of the propeller(s) [m]
RCH = resistance [N] of the ship in a channel with brash ice and a consolidated layer :
RCH = C1 + C2 + C3 @ Cμ ( HF + HM )2
@ (B + Cψ @ HF) + C4 @ LPAR @ + C5 [N]
C1 and C2 take into account a consolidated upper layer of the brash ice and can be taken as zero for ice Class Notations ES1,
ES2 and ES3.
For ice class ES4 :
C1 = f1 @ (f2 @ B + f3 @ LBOW + f4 @ B @ LBOW)
C2 = (1 + 0,063 n1) (g1 + g2 @ B) + g3
C3 = 845 [kg/m2
/s2
]
C4 = 42 [kg/m2
/s2
]
C5 = 825 [kg/s2
]
Cμ = 0,15 cos n2 + sin ψ @ sin α; Cμ $ 0,45
Cψ = 0,047 ψ – 2,115; Cψ = 0 for ψ # 45°
HF = thickness of the brash ice layer displaced by the bow [m]
= 0,26 +
HM = thickness of the brash ice in mid channel [m]
= 1,0 for ice class notations ES3 and ES4
= 0,8 for ice class notations ES2
= 0,6 for ice class notation ES1
The ship parameters defined below are to be calculated on the UIWL using a horizontal waterline passing through the
maximum ice class draught amidships, as defined in 2.1, and on the LIWL using a horizontal waterline passing through the
minimum ice class draught amidships, as defined in 2.3. The ship dimensions LPP and B, however, are always to be
calculated on the UIWL. See also Fig. 15.1. The lengths of the bow, LBOW, on the UIWL and LIWL are both to be
measured from the fore perpendicular defined on the UIWL. The length of the parallel midship body, LPAR, is to be
measured between the aft perpendicular and the flat of side, if the vessel has a full beam between these two points.
LPAR = length of the parallel midship body [m]
LPP = length of the ship between perpendiculars [m]
LBOW = length of the bow [m]
T = maximum and minimum ice class draughts amidship [m] according to 2.1 and 2.3, respectively
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![Section 15 - Strengthening for Navigation in Ice A 15-5/17
Awf = area of the waterplane of the bow [m2
]
n1 = the rake of the stem at the centreline [°]
For a ship with a bulbous bow, n1 shall be taken as 90°.
n2 = the rake, of the bow at B/4 [°], n2max = 90°
α = the angle of the waterline at B/4 [°]
ψ = arctan
The quantity
is not to be taken less than 5 and not to be taken more than 20.
f1 = 23 [N/m2
], g1 = 1 530 [N]
f2 = 45,8 [N/m], g2 = 170 [N/m]
f3 = 14,7 [N/m], g3 = 400 [N/m1,5
]
f4 = 29 [N/m2
]
Ship's parameters are generally to be within the ranges of validity shown in Table 15.3 if the above formula for RCH is to
be used. Otherwise, alternative methods for determining RCH are to be used as specified in 3.4.When calculating the
parameter DP/T, T shall be measured on the UIWL.
Table 15.3 - Range of application of the formula for ship resistance RCH
Parameter Minimum Maximum
α [°] 15 55
n1 [°] 25 90
n2 [°] 10 90
Lpp [m] 65,0 250,0
B [m] 11,0 40,0
T [m] 4,0 15,0
LBOW/Lpp 0,15 0,40
LPAR/Lpp 0,25 0,75
Dp/T 0,45 0,75
Awf / (Lpp @ B) 0,09 0,27
3.4 For an individual ship, in lieu of the Ke or RCH values defined in 3.3, the use of Ke values based on more exact
calculations or RCH values based on model tests may be approved (see also paragraph 7.4 of the Guidelines for the
Application of the Finnish-Swedish Ice Class Rules). If RCH is determined using the rule formulae, then Ke can be
determined by using direct calculations or the rule formulae. However, if RCH is determined using model tests, then propeller
thrust should be calculated by direct calculations using the actual propeller data.
Such approvals will be given on the understanding that they can be revoked if warranted by the actual performance of the
ship in ice.
The design requirement for ice classes is a minimum speed of 5 kn in the following brash ice channels :
ES4 = HM = 1,0 m and a 0,1 m thick consoli-dated layer of ice
ES3 = HM = 1,0 m
ES2 = HM = 0,8 m
ES1 = HM = 0,6 m
4. Definitions for ships notations ES1-ES4
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![A Section 15 - Strengthening for Navigation in Ice15-6/17
4.1 Ice belt
4.1.1 The ice belt is the zone of the shell plating which is to be strengthened. The ice belt is divided into regions as
follows, see Fig. 15.2 :
.1 Forward region F
The region from the stem to a line parallel to and at the distance c aft of the borderline between the parallel midship
region and the fore ship;
c = 0,04 L, not exceeding 6 m for the ice Class Notation ES3 and ES4, not exceeding 5 m for the ice class
notations ES1- ES2
= 0,02 L, not exceeding 2 m for the ice class notation ES.
.2 Midship region M
The region from the aft boundary of the region F, as defined in .1 to a line parallel to and at the distance c aft of the
borderline between the parallel midbody region and the aft ship ;
.3 Aft region A
The region from the aft boundary of the region M, as defined in .2 to the stern;
.4 Fore foot FF
(for ice class notation ES4 only)
The region below the ice belt from the stem to a position five main frame spaces abaft the point where the bow profile
departs from the keel line;
.5 Upper forward ice belt FU
(for ice class notations ES3 and ES4 on ships with a speed v0 $ 18 kn only)
The region from the upper limit of the ice belt to 2 m above it and from the stem to a position 0,2 L abaft the forward
perpendicular.
4.1.2 The vertical extension of the regions F, M, and A is to be determined from Table 15.4.
4.1.3 On the shell expansion plan submitted for approval, the location of the UIWL, LIWL and the upper/lower limits
of the ice belt, as well as the regions F, M and A (including FF and FU, if applicable), are to be clearly indicated.
Table 15.4 - Vertical extension of the regions F, M and A
Ice class notation
Below
LIWL [m]
Above
UIWL [m]
ES, ESl
ES2
ES3
ES4
0,5
0,5
0,6
0,75
0,4
0,4
0,5
0,6
4.1.4 The following terms are used in the formulae in B:
a = frame spacing [m], longitudinal or transverse, taking into account the intermediate frames, if fitted.
ReH = minimum nominal upper yield point for hull structural steel according to Section 2, B.2.
R = unsupported span [m] of frames, web frames, stringer. See also Section 3, C.3.
p = design ice pressure [N/mm2
] according to B.2.2
h = design height of ice pressure area [m] according to B.2.1.
The frame spacing and spans are normally to be measured in a vertical plane parallel to the centreline of the ship. However,
if the ship's side deviates more than 20° from this plane, the frame spacing and spans shall be measured along the side of
the ship.
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![Section 15 - Strengthening for Navigation in Ice A, B 15-7/17
Fig. 15.1 - Rake of the stem n1 and rake of the bow n2 at B/4 from CL
Fig. 15.2 Ice belt
B. Requirements for the Notations ES1 – ES4
1. General
1.1 A typical ice load distribution is shown in Fig.15.3. Maximum pressures (pmax) occur at the frames, minimum
pressures occur between frames, due to different flexural stiffness of frames and shell plating.
Fig. 15.3 - Ice load distribution
The formulae for determining the scantlings used in this Section are based on the following design loads :
for frames :
p = ( pmax + pmin ) [N/mm2
]
for shell plating :
p1 = 0,75 p [N/mm2
]
p = design ice pressure as per 2.2.
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![B Section 15 - Strengthening for Navigation in Ice15-8/17
1.2 The formulae given in this Section may be substituted by direct calculation methods, subject to approval by BKI.
2. Ice loads
2.1 An ice strengthened ship is assumed to operate in open sea conditions corresponding to a level ice thickness not
exceeding h0. The design height, h, of the area actually under ice pressure is, however, assumed to be less than h0. The
values for h0 and h are given in Table 15. 5.
Table 15.5 - Ice thickness h0 and design height h
Ice class notation h0 [m] h [m]
ES, ES1
ES2
ES3
ES4
0,4
0,6
0,8
1,0
0,22
0,25
0,30
0,35
2.2 The design ice pressure is to be determined according to the following formula :
p = cd @ c1 @ ca @ p0 [N/mm2
]
cd =
k =
Pmax = 740 kW for the ice class notation ES
a, b = coefficients in accordance with Table 15.6
Table 15.6 - Coefficients a and b
Region F M and A
k 12 > 12 12 > 12
a
b
30
230
6
518
8
214
2
286
D see A.2.4
P = total maximum output the propulsion machinery can continuously deliver to the propeller(s)[kW], see also
A.3.1
c1 = coefficient in accordance with Table 15.7
ca = max. 1,0, min. 0,6
Ra = effective length [m] according to Table15.8
p0 = 5,6 N/mm2
(nominal ice pressure).
Table 15.7 - Coefficient c1
Ice class notation
Region
F M A
ES
ES1
ES2
ES3
ES4
0,3
1,0
1,0
1,0
1,0
!
0,50
0,70
0,85
1,00
!
0,25
0,45
0,65
0,75
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![Section 15 - Strengthening for Navigation in Ice B 15-9/17
Table 15.8 - Effective length Ra
Structure
Type of
framing
Ra
Shell
Transverse frame spacing
Longitudinal 2 x frame spacing
Frames
Transverse frame spacing
Longitudinal span of frame
Ice stringer span of stringer
Web frame 2 x web frame spacing
3. Thickness of shell plating in the ice belt
3.1 The thickness of the shell plating is to be determined according to the following formulae:
.1 transverse framing:
t = 667 a + tc [mm]
.2 longitudinal framing :
t = 667 a + tc [mm]
p1 see 1.1
f1 = 1,3 !
f1max = 1,0
f2 = 0,6 + , where h/a # 1
= 1,4 ! , where 1 < h/a # 1,8
tc = allowance for abrasion and corrosion [mm]. Usually tc amounts to 2 mm. If a special coating is applied and
maintained, which by experience is shown to be capable to withstand the abrasion of ice, the allowance may
be reduced to 1 mm.
3.2 Where the draught (e.g., in the ballast condition) is smaller than 1,5 m, or where the distance between the lower
edge of the ice belt and the keel plate is smaller than 1,5 m, the thickness of the bottom plating in way of the ice belt region
F is not to be less than required for the ice belt. In the same area the thickness of the plate floors is to be increased by 10
%.
3.3 Side scuttles are not to be situated in the ice belt. If the weather deck in any part of the ship is situated below the
upper limit of the ice belt, see A.4.1.2 (e.g. in way of the well of a raised quarter decker), the bulwark is to have at least the
same strength as is required for the shell in the ice belt. Special consideration has to be given to the design of the freeing
ports.
3.4 For ships with the ice Class Notation ES4 the region FF according to A.4.1.1.4 shall have at least the thickness
of the region M.
3.5 For ships with the ice Class Notation ES3 or ES4 and with a speed v0 $ 18 kn the region FU according to
A.4.1.1.5 shall have at least the thickness of the region M.
A similar strengthening of the bow region is also advisable for a ship with a lower service speed when it is evident that the
ship will have a high bow wave, e.g. on the basis of model tests.
4. Frames, ice stringers, web frames
4.1 General
4.1.1 Within the ice-strengthened area, all frames are to be effectively attached to the supporting structures.
Longitudinal frames are generally to be attached to supporting web frames and bulkheads by brackets. Brackets may be
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![B Section 15 - Strengthening for Navigation in Ice15-10/17
omitted with an appropriate increase in the section modulus of the frame (see 4.3.1) and with the addition of heel stiffeners
(heel stiffeners may be omitted on the basis of direct calculations, subject to approval by BKI). Brackets and heel stiffeners
are to have at least the same thickness as the web plate of the frame and the free edge has to be appropriately stiffened
against buckling. When a transverse frame terminates at a stringer or deck, a bracket or similar construction is to be fitted.
When a frame is running through the supporting structure, both sides of the web are to be connected to the structure by direct
welding, collar plate or lug.
4.1.2 For the ice Class Notation ES4, for the ice Class Notation ES3 within the regions F and M and for the ice class
notations ES2 and ES1 within the region F the following applies :
.1 Frames with webs which are not at perpendicular to the shell are to be supported against tripping by brackets,
intercostal plates, stringers or similar at a distance not exceeding 1300 mm.
.2 The frames are to be attached to the shell by double continuous welds. No scalloping is allowed except when crossing
shell plate butts welds.
.3 The web thickness of the frames is to be at least one half of the thickness of the shell plating and at least 9 mm, The
latter minimum value is independent of the material factor k according to Section 2, B.2.1. However, the web thickness
of frames need not exceed one half of the shell plating thickness required for a frame spacing of 0,45 m, assuming a
yield stress for the plating not greater than that for the framing.
.4 Where there is a deck, tank top, bulkhead, web frame or stringer in lieu of a frame, its plate thickness of this is to be
as required in accordance with .3, to a depth corresponding to the height of adjacent frame.
4.1.3 For transverse framing above UIWL and below LIWL, as well as longitudinal framing below LIWL, the vertical
extension of the ice strengthened framing bE is to be determined according to Table 15.9.
Where the vertical extension of ice-strengthened transverse framing bE would extend beyond a deck or a tank top by not
more than 250 mm, it may be terminated at that deck or tank top.
For longitudinal framing above UIWL the vertical extension of the ice-strengthening should be extended up to and including
the first frame above the upper edge of the ice belt. Additionally, the spacing between the longitudinal frames directly above
and below the edge of the ice belt should be the same as the frame spacing in the ice belt. If the first frame above the ice
belt is closer than approximately a/2 to the upper edge of the ice belt, then the same frame spacing as in the ice belt should
be extended to the second frame above the upper edge of the ice belt.
Table 15.9 Vertical extension bE of ice strengthened framing
Ice class notation Region
bE
Above UIWL [m]
Below LIWL
[m]
ES
F, from stem to 0,075 L
abaft it
1,0
1,0
ES1
ES2
ES3
F, from stem to 0,3 L abaft
it
1,6
F, abaft 0,3 L from stem to
aft boundary of region F
1,3
M 1,3
A 1,0
FU 1)
2,5
ES4
F, from stem to 0,3 L abaft
it
1,2
To double bottom or below
top of floors
F, abaft 0,3 L from stem to
aft boundary of region F
1,6
M 1,6
A 1,2
FU 1)
2,6
1)
If required according to A.4.1.1.5.
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![Section 15 - Strengthening for Navigation in Ice B 15-11/17
4.2 Transverse frames
4.2.1 The section modulus of a main, 'tweendeck or intermediate transverse frame is to be determined according to the
following formula:
W = [cm3
]
mt =
m0 = coefficient according to Table 15.10.
The boundary conditions referred to in Table 15.10 are those for the intermediate frames. Other boundary conditions for
main frames and 'tweendeck frames are assumed to be covered by interaction between the frames. This influence is included
in the m0 values. The load centre of the ice load is taken at R/2.
Where less than 15 % of the span R, is situated within the ice-strengthening zone for frames as defined in 4.1.3, ordinary
frame scantlings may be used.
4.2.2 Upper end of transverse framing
4.2.2.1 The upper end of the ice- strengthened part of all frames is to be attached to a deck or an ice stringer as per 4.4.
Table 15.10 - Boundary conditions for transverse frames
Boundary
Condition
m0 Example
7
Frames in bulk carrier with
top wing tanks
6
Frames extending from the
tank top to a single deck
5,7
Continuous frames between
several decks or stringers
5
Frames extending between
two decks only
4.2.2.2 Where a frame terminates above a deck or stringer, which is situated at or above the upper limit of the ice belt
(see A.4.1.2), the part above the deck or stringer need not be ice-strengthened. In such cases, the upper part of the
intermediate frames may be connected to the adjacent main or 'tweendeck frames by a horizontal member of the same
scantlings as the main and 'tweendeck frames, respectively. Such intermediate frames may also be extended to the deck
above and, if this is situated more than 1,8 m above the ice belt, the intermediate frame need not be attached to that deck,
except in the forward region F.
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![B Section 15 - Strengthening for Navigation in Ice15-12/17
4.2.3 Lower end of transverse framing
4.2.3.1 The lower end of the ice strengthened part of all frames is to be attached to a deck, inner bottom, tanktop or ice
stringer as per 4.4.
4.2.3.2 Where an intermediate frame terminates below a deck, tanktop or ice stringer which is situated at or below the
lower limit of the ice belt (see A.4.1.2), its lower end may be connected to the adjacent main or 'tweendeck frames by a
horizontal member of the same scantlings as the respectively main and 'tweendeck frames, respectively.
4.3 Longitudinal frames
The section modulus and the shear area of the longitudinal frames are to be determined according to the following formulae:
.1 section modulus:
W = [cm3
]
.2 shear area:
A = [cm2
]
f3 = factor which takes account of the load distribution to adjacent frames
= 1 - 0,2 h/a
f4 = 0,6
m = boundary condition factor
= 13,3 for a continuous beam with double end brackets
= 11,0 for a continuous beam without double end bracket.
Where the boundary conditions are considerably different from those of a continuous beam, e.g. in an end
field, a smaller factor m may be determined
4.4 Ice stringers
4.4.1 Ice stringers within the ice belt
The section modulus and the shear area of a stringer situated within the ice belt are to be determined according to the
following formulae :
.1 section modulus:
W = [cm3
]
.2 shear area:
A = [cm2
]
p @ h is not to be taken as less than 0,3
m = see 4.3
f5 = factor which takes account of the distribution of load to the transverse frames; to be taken as 0,9
4.4.2 Ice stringers outside the ice belt
The section modulus and the shear area of a stringer situated outside the ice belt, but supporting frames subjected to ice
pressure, are to be calculated according to the following formulae:
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![Section 15 - Strengthening for Navigation in Ice B 15-13/17
.1 section modulus:
W = [cm3
]
.2 shear area:
A = [cm2
]
p @ h is not to be taken as less than 0,3
f6 = factor which takes account of the distribution of load to the transverse frames; to be taken as 0,95
m = see 4.3
hs = distance of the stringer to the ice belt [m]
Rs = distance of the stringer to the adjacent ice stringer or deck or similar structure [m].
4.4.3 Deck strips
4.4.3.1 Narrow deck strips abreast of hatches and serving as ice stringers are to comply with the section modulus and
shear area requirements in 4.4.1 and 4.4.2 respectively. In the case of very long hatches, the product p @ h may be taken less
than 0,30 but in no case less than 0,20.
4.4.3.2 When designing weatherdeck hatchcovers and their fittings, the deflection of the ship's sides due to ice pressure
in way of very long hatch openings is to be considered.
4.5 Web frames
4.5.1 The load transferred to a web frame from a stringer or from longitudinal framing is to be calculated according
to the following formula:
P = p @ h @ e @ 103
[kN]
p @ h is not to be taken as less than 0,3
e = web frame spacing [m].
In case the supported stringer is outside the ice belt, the load P may be multiplied by
where hs and Rs shall be taken as defined in 4.4.2.
4.5.2 Shear area and section modulus
For the case of simple support at the upper end and constraint at the lower end according to Fig. 15.4, shear area and section
modulus can be calculated by the following formulae :
shear area :
A = [cm2
]
Q = P @ k1 [kN]
k1 = 1 + or
= ,
whichever is greater.
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![B Section 15 - Strengthening for Navigation in Ice15-14/17
For the lower part of the web frame, the smallest RF within the ice belt is to be used. For the upper part, the biggest RF within
the ice belt is to be taken.
R, RF [m] according to Fig. 15.4.
Fig. 15.4 - Lengths R and RF
α = see Table 15.11
P = as in 4.5.1
section modulus :
W = [cm3
]
M = P @ R @ k2 [kNm]
k2 =
Aa = actual shear area
A = required shear area as above, but by using
k1 = 1 +
γ = see Table 15.11
4.5.3 For web frame configurations and boundary conditions than given in 4.5.2, a direct stress calculation is to be
performed. The point of application of the load P is in each case to be chosen in relation to the arrangement of stringers and
longitudinal frames so as to obtain the maximum shear and bending moments.
4.5.4 At any position of the web frame the equivalent stress due to bending and shear is to comply with the following
condition :
σv =
5. Stem
5.1 The stem may be made of rolled, cast or forged steel or of shaped steel plates. A sharp edged stem (see Fig. 15.5)
improves the manoeuvrability of the ship in ice and is particularly recommended for ships less than 150m in length.
5.2 The plate thickness of a shaped plate stem and, in the case of a blunt bow, any part of the shell which forms an
angle β (see Fig. 15.5) of 30o
or more to the centre line in a horizontal plane, is to be calculated according to the formulae
in 3.1 observing that:
p1 = p
a = smaller of the two unsupported widths of plate panel [m]
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![Section 15 - Strengthening for Navigation in Ice B 15-15/17
Ra = spacing of vertical supporting elements [m] (see also Table 15.8)
Fig. 15.5 Stem
5.3 The stem and the part of a blunt bow defined in 5.2 (if applicable), are to be supported by floors or brackets
spaced not more than 0,6 m apart and having a thickness of at least half the plate thickness according to 5.2. The
reinforcement of the stem shall extend from the keel to a point 0,75 m above UIWL or, in case an upper forward ice belt
is required (see also A.4.1.1) to the upper limit of the region FU.
Table 15.11 - Coefficient a and . for the calculation of required shear area and section modulus
0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40 1,60 1,80 2,00
α 1,50 1,23 1,16 1,11 1,09 1,07 1,06 1,05 1,05 1,04 1,04
γ 0,00 0,44 0,62 0,71 0,76 0,80 0,83 0,85 0,87 0,88 0,89
Af = cross sectional area of free flange
Aw = cross sectional area of web plate
6. Arrangements for towing
6.1 A mooring pipe with an opening not less than stated below is to be fitted in the bow bulwark at the centreline.
size of opening : 250 x 300 [mm]
length : 150 [mm]
inner surface radius : 100 [mm]
6.2 A bitt or other means for securing a towline, dimensioned to withstand the breaking force of the towline of the
ship, is to be fitted. Alternatively, two fairleads can be fitted symmetrically off the centreline with one bitt each. The bitts
shall be aligned with the fairleads allowing the towlines to be fastened straight onto them. The installation of a centreline
fairlead is still recommended, since it remains useful for many open water operations as well as some operations in ice.
6.3 On ships with a displacement not exceeding 30.000 t the part of the bow which extends to a height of a least
5 m above the UIWL and at least 3 m aft of the stem, is to be strengthened for the loads caused by fork towing. For this
purpose intermediate frames and additional stringers or decks are to be fitted.
Note
Fork towing in ice is often the most efficient way of assisting ships of moderate size (as defined in 6.3). Ships with a bulb
protruding more than 2,5 m forward of the forward perpendicular are often difficult to tow in this way. Some national
authorities may deny assistance to such ships if the circumstances so warrant.
7. Stern
7.1 An extremely narrow clearance between the propeller blade tip and the stern frame is to be avoided as a small
clearance would cause very high loads on the blade tips.
7.2 On twin and triple screw ships the ice strengthening of the shell and framing shall be extended to the double
bottom to an extent of 1,5 m forward and aft of the side propellers.
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![B Section 15 - Strengthening for Navigation in Ice15-16/17
7.3 Shafting and stern tubes of side propellers are normally to be enclosed within plated bossings. If detached struts
are used, their design, strength and attachment to the hull are to be duly considered.
7.4 A wide transom stern extending below the UIWL will seriously impede the capability of the ship to back in ice,
which is most essential. Therefore, a transom stern is not to extend below the UIWL if this can be avoided. If unavoidable,
the part of the transom below the UIWL is to be kept as narrow was possible. The part of a transom stern situated within
the ice belt shall be strengthened as for the midship region M.
7.5 Propulsion arrangements with azimuthing thrusters or "podded" propellers, which provide an improved
manoeuverability, result in increased ice loading of the aft region and stern structure.
Due consideration is to be given to this increased ice loading in the design and dimensioning of the aft region and stern
structure.
8. Bilge keels
To limit damage to the shell when a bilge keel is partly ripped off in ice, it is recommended that bilge keels are divided into
several shorter independent lengths.
9. Rudder and steering gear
9.1 When calculating the rudder force and torsional moment according to Section 14, B.1. the ship's speed v0 is not
to be taken less than given in Table 15.12.
All scantlings dimensioned according to the rudder force and the torsional moment respectively (rudder stock, rudder
coupling, rudder horn etc.) as well as the capacity of the steering gear are to be increased accordingly where the speed stated
in Table 15.12 exceeds the ship's service speed.
Independent of rudder profile the coefficient κ2 according to Section 14, B.1.1 need not be taken greater than κ2 = 1,1
in connection with the speed values given in Table 15.12.
Table 15.12 - Minimum speed for the dimensioning of rudder
Ice class notation v0 [kn]
ES1
ES2
ES3
ES4
14
16
18
20
The factor κ3 according to Section 14, B.1.1 need not be taken greater than 1,0 for rudders situated behind a nozzle.
9.2 Within the ice belt (as per A.4.1) the thickness of the rudder plating is to be determined as of the shell plating
within the region A. The thickness of webs shall not to be less than half the rudder plating thickness.
9.3 For the ice Class Notations ES3 and ES4, the rudder stock and the upper edge of the rudder are to be protected
against ice pressure by an ice knife or equivalent means. Special consideration shall be given to the design of the rudder and
the ice knife for vessels with a flap-type rudder.
9.4 For ships with the ice Class Notations ES3 and ES4 due regard is to be paid to the excessive arising when the
rudder is forced out of the midship position while backing into an ice ridge. A locking device according to Section 14, G.2.
is regarded sufficient to absorb these loads.
Note
For ships sailing in low temperature areas, small gaps between the rudder and ship's hull may cause the rudder to become
fixed to the hull through freezing. It is therefore recommended to avoid gaps less than 1/20 of the rudder body width or 50
mm, whichever is less, or to install suitable means such as heating arrangements.
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![Section 16 - Superstructures and Deckhouses A 16-1/9
Section 16
Superstructures and Deckhouses
A. General
1. Definitions
1.1 A superstructure is a decked structure on the freeboard deck extending from side to side of the ship or with the
side plating not being inboard of the shell plating more than 0,04 B.
1.2 A deckhouse is a decked structure above the strength deck the side plating being inboard of the shell plating more
than 0,04 B.
1.3 A long deckhouse is a deckhouse the length of which within 0,4 L amidships exceeds 0,2 L or 12 m, where the
greater value is decisive. The strength of a long deckhouse is to be specially considered.
1.4 A short deckhouse is a deckhouse not covered by the definition given in 1.3.
1.5 Superstructures extending into the range of 0,4 L amidships and the length of which exceeds 0,15 L are defined
as effective superstructures. Their side plating is to be treated as shell plating and their deck as strength deck (see Sections
6 and 7).
1.6 All superstructures being located beyond 0,4 L amidships or having a length of less than 0,15 L or less than 12
metres are, for the purpose of this Section, considered as non-effective superstructures.
1.7 For deckhouses of aluminium, Section 2, D. is to be observed. For the use of non-magnetic material in way of
the wheel house, see Section 14, A.1.4.
1.8 Scantlings of insulated funnels are to be determined as for deckhouses.
1.9 Throughout this Section the following definitions apply:
k = material factor according to Section 2, B.2
ps = load according to Section 4, B 2.1.
pe = load according to Section 4, B 2.2.
pD = load according to Section 4, B.1.
pDA = load according to Section 4, B.5.
pL = load according to Section 4, C.1.
tK = corrosion addition according to Section 3, K.
2. Arrangement of superstructure
2.1 According to ICLL, Regulation 39, a minimum bow height is required at the forward perpendicular, which may
be obtained by sheer extending for at least 0,15 Lc, measured from the forward perpendicular or by fitting a forecastle
extending from the stem to a point at least 0,07 Lc abaft the forward perpendicular.
2.2 Ships carrying timber deck cargo and which are to be assigned the respective permissible freeboard, are to have
a forecastle of the Rule height and a length of at least 0,07 Lc. Furthermore, ships the length of which is less than 100 m,
are to have a poop of Rule height or a raised quarter deck with a deckhouse.
3. Strengthenings at the ends of superstructures
3.1 At the ends of superstructures one or both end bulkheads of which are located within 0,4 L amidships, the
thickness of the sheer strake, the strength deck in a breadth of 0,1 B from the shell, as well as the thickness of the
superstructure side plating are to be strengthened as specified in Table 16.1. The strengthenings shall extend over a region
from 4 frame spacings abaft the end bulkhead to 4 frame spacings forward of the end bulkhead.
Table 16.1 Strengthening [%] at the ends of superstructures
Type of superstructure Strength deck and sheer strake Side plating of superstructure
effective according to 1.5 30 20
non effective according to 1.6 20 10
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![A, B Section 16 - Superstructures and Deckhouses16-2/9
3.2 Under strength decks in way of 0,6 L amidships, girders are to be fitted in alignment with longitudinal walls,
which are to extend at least over three frame spacings beyond the end points of the longitudinal walls. The girders are to
overlap with the longitudinal walls by at least 2 frame spacings.
4. Transverse structure of superstructures and deckhouses
The transverse structure of superstructures and deckhouses is to be sufficiently dimensioned by a suitable arrangement of
end bulkheads, web frames, steel walls of cabins and casings, or by other measures.
5. Openings in closed superstructures
5.1 Allaccessopeningsinendbulkheadsofclosedsuperstructuresshallbefittedwith weathertight doors permanently
attached to the bulkhead, having the same strength as the bulkhead. The doors shall be so arranged that they can be operated
from both sides of the bulkhead. The coaming heights of the access opening above the deck are to be determined according
to ICLL.
5.2 Any opening in a superstructure deck or in a deckhouse deck directly above the freeboard deck (deckhouse
surrounding companionways), is to be protected by efficient weathertight closures.
6. Recommendations regarding deckhouse vibration
6.1 Thenaturalfrequenciesofthebasicglobaldeckhousevibrationmodes(longitudinal,transverse,torsional) should
not coincide with major excitation frequencies at the nominal revolution rate of the propulsion plant. This should be verified
during the design stage by a global vibration analysis.
6.2 The natural frequencies of local deck panel structure components (plates, stiffeners, deck frames, longitudinal
girders, deck grillages) should not coincide with major excitation frequencies at the nominal revolution rate of the
propulsion plant. This should be verified during the design stage by a local vibration analysis.
6.3 It is recommended to design the local deck structures in such a way that their natural frequencies exceed twice
propeller blade rate, and in case of rigidly mounted engines ignition frequency, by at least 20 %. This recommendation is
based on the assumption of a propeller with normal cavitation behaviour, i.e. significant decrease of pressure pulses with
increasing blade harmonic shall be ensured.
6.4 Cantilever navigation bridge wings should be supportedbypillarsorbracketsextendingfromtheouterwing edge
to at least the deck level below. If this is not possible, the attachment points of the pillars/brackets at the deckhouse structure
have to be properly supported.
6.5 The base points of the main mast located on the compass deck should be preferably supported by walls or pillars.
The natural frequencies of the basic main mast vibration modes (longitudinal, transverse, torsional) should not coincide
with major excitation frequencies at the nominal revolution rate of the propulsion plant. This should be verified during the
design stage by a mast vibration analysis.
B. Side Plating and Decks of Non-Effective Superstructures
1. Side plating
1.1 The thickness of the side plating above the strength deck is not to be less than the greater of the following values:
t = [mm]
or
t = 0,8 @ tmin [mm]
p = ps or pe , as the case may be
tmin = see Section 6, B. 3.1.
1.2 The thickness of the side plating of upper tier superstructures may be reduced if the stress level permits such
reduction.
2. Deck plating
2.1 The thickness of deck plating is not to be less than the greater of the following values:
t = [mm]
t = [mm]
p = pDA or pL, the greater value is to be taken.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-240-320.jpg)
![Section 16 - Superstructures and Deckhouses B, C 16-3/9
C = 1,21,if p = pDA
= 1,1, if p = pL
L need not be taken greater than 200 m.
2.2 Where additional superstructures are arranged on non-effective superstructures located on the strength deck, the
thickness required by 2.1 may be reduced by 10 %.
2.3 Where plated decks are protected by sheathing, the thickness of the deck plating according to 2.1 and 2.2 may
be reduced by tK, however, it is not to be less than 5 mm.
Where a sheathing other than wood is used, attention is to be paid that the sheathing does not affect the steel. The sheathing
is to be effectively fitted to the deck.
3. Deck beams, supporting deck structure, frames
3.1 The scantlings of the deck beams and the supporting deck structure are to be determined in accordance with
Section 10.
3.2 The scantlings of superstructure frames are given in Section 9, A.3.
C. Superstructure End Bulkheads and Deckhouse Walls
1. General
The following requirements apply to superstructure end bulkheads and deckhouse walls forming the only protection for
openings as per Regulation 18 of ICLL and for accommodations. These requirements also apply to breakwaters, see also
F.
2. Definitions
The design load for determining the scantlings is:
pA = n @ c ( b @f– z ) [kN/m2
]
f = cL @ c0
cL, c0= see Section 4,A.2.2
hN = standard superstructure height
= 1,05 + 0,01 L [m] , 1,8 < hN < 2,3
n =
for the lowest tier of unprotected fronts. The lowest tier is normally that tier which is directly situated above
the uppermost continuous deck to which the Rule depth H is to be measured. However, where the actual
distance H - T exceeds the minimum non-corrected tabular freeboard according to ICLL by at least one
standard superstructure height hN, this tier may be defined as the 2nd
tier and the tier above as the 3rd
tier
= for 2nd
tier unprotected fronts
= for 3rd
tier and tiers above of unprotected fronts, for sides and protected fronts
= for aft ends abaft of amidships
= for aft ends forward of amidships
= for breakwaters forward of $ 0,85
L need not be taken greater than 300 m.
b = 1,0 + for < 0,45
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-241-320.jpg)
![C Section 16 - Superstructures and Deckhouses16-4/9
b = 1,0 + 1,5 for 0,45
b = 1,0 + 2,75 for breakwaters forward of 0,85
0,60 CB 0,80; when determining scantlings of aft ends forward of amidships, CB need not be taken less than 0,8.
x = distance [m] between the bulkhead considered or the breakwater and the aft end of the length L. When
determining sides of a deckhouse, the deckhouse is to be subdivided into parts of approximately equal
length, not exceeding 0,15 L each, and x is to be taken as the distance between aft end of the length L
and the centre of each part considered.
z = vertical distance [m] from the summer load line to the midpoint of stiffener span, or to the middle of the
plate field.
c = 0,3 + 0,7 b'/B'
For exposed parts of machinery casings and breakwaters, c is not to be taken less than 1,0.
b' = breadth of deckhouse at the position considered
B' = actual maximum breadth of ship on the exposed weather deck at the position considered.
b'/B' is not to be taken less than 0,25.
a = spacing of stiffeners [m]
R = unsupported span [m]; for superstructure end bulkheads and deckhouse walls, R is to be taken as the
superstructure height or deckhouse height respectively, however, not less than 2,0 m.
The design load pA up to the third tier inclusive is not to be taken less than the minimum values given in Table 16.2.
For breakwaters, the minimum design load is to be the same as for the lowest tier of unprotected fronts.
Table 16.2 Minimum design load pAmin
L
pAmin [kN/m2
] for
lowest tier of unprotected
fronts and breakwaters
elsewhere
50 30 15
> 50
250
250 50 25
For the 4th
tier and all following ones pAmin is to be taken as 12,5 kN/mm2
3. Scantlings
3.1 Stiffeners
The section modulus of the stiffeners is to be determined according to the following formula:
W = 0,35 @ a @ R2
@ pA @ k [cm3
]
These requirements assume the webs of lower tier stiffeners to be efficiently welded to the decks. Scantlings for other types
of end connections may be specially considered.
The section modulus of house side stiffeners needs not be greater than that of side frames on the deck situated directly
below; taking account of spacing a and unsupported span R.
3.2 Plate thickness
The thickness of the plating is to be determined according to the greater values of the following formula :
t = 0,9 @ a [mm]
tmin = [mm]
for the lowest tier and for breakwaters
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-242-320.jpg)
![Section 16 - Superstructures and Deckhouses C, D 16-5/9
= [mm]
for the upper tiers, however not less than 5 mm
for tug 4,5 mm
L need not be taken greater than 300 m.
D. Decks of Short Deckhouses
1. Plating
The thickness of deck plating exposed to weather but not protected by sheathing is not to be less than:
t = 8 @ a + tK [mm]
For weather decks protected by sheathing and for decks within deckhouses the thickness may be reduced by tK.
In no case the thickness is to be less than the minimum thickness tmin = 5,0 mm.
2. Deck beams
The deck beams and the supporting deck structure are to be determined according to Section 10.
E. Elastic Mounting of Deckhouses
1. General
1.1 The elastic mountings are to be type approved by BKI. The stresses acting in the mountings which have been
determined by calculation are to be proved by means of prototype testing on testing machines. Determination of the grade
of insulation for transmission of vibrations between hull and deckhouses is not part of this type approval.
1.2 The height of the mounting system is to be such that the space between deck and deckhouse bottom remains
accessible for repair, maintenance and inspection purposes. The height of this space shall normally not be less than 600
mm.
1.3 For the fixed part of the deckhouse on the weather deck, a coaming height of 380 mm is to be observed, as
required by ICLL for coamings of doors in superstructures which do not have access openings to under deck spaces.
1.4 For pipelines, see Rules for Machinery Installations, Volume III, Section 11.
1.5 Electric cables are to be fitted in bends in order to facilitate the movement. The minimum bending radius
prescribed for the respective cable is to be observed. Cable glands are to be watertight. For further details, see Rules for
Electrical Installations, Volume IV.
1.6 The following scantling requirements forrails, mountings, securingdevices,stoppersand substructures in the hull
and the deckhouse bottom apply to ships in unrestricted service. For special ships and for ships intended to operate in
restricted service ranges requirements differing from those given below may be applied.
2. Design loads
For scantling purposes the following design loads apply:
2.1 Weight
2.1.1The weight induced loads result from the weight of the fully equipped deckhouse, considering also the acceleration
due to gravity and the acceleration due to the ship's movement in the seaway. The weight induced loads are to be assumed
to act in the centre of gravity of the deckhouse.
The individual dimension less accelerations az (vertically), ay (transversely) and ax (longitudinally) and the dimension less
resultant acceleration aβ, are to be determined according to Section 4, E. for k = 1,0 and f = 1,0.
Due to the resultant acceleration aβ the following load is acting:
P = [kN]
G = mass of the fully equipped deckhouse [t]
g = 9,81 m/s2
2.1.2The support forces in the vertical and horizontal directions are to be determined for the various angles β. The scantlings
are to be determined for the respective maximum values (see also Fig. 16.1).
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-243-320.jpg)
![E Section 16 - Superstructures and Deckhouses16-6/9
Fig. 16.1 Support forces
2.2 Water pressure and wind pressure
2.2.1The water load due to the wash of the sea is assumed to be acting on the front wall in the longitudinal direction only.
The design load is :
pwa = 0,5 @ pA [kN/m2
]
pA = see C.2
The water pressure is not to be less than :
pwa = 25 [kN/m2
] at the lower edge of the front wall
= 0 at the level of the first tier above the deckhouse bottom
Pwa = pwa @ Af [kN]
Af = loaded part of deckhouse front wall [m2
]
2.2.2The design wind load acting on the front wall and on the side walls is:
Pwi = AD @ pwi [kN]
AD = area of wall [m2
]
pwi = 1,0 [kN/m2
]
2.3 Load on the deckhouse bottom
The load on the deckhouse bottom is governed by the load acting on the particular deck on which the deckhouse is located.
Additionally, the support forces resulting from the loads specified in 2.1 and 2.2 are to be taken into account.
2.4 Load on deck beams and girders
For designing the deck beams and girders of the deck on which the deckhouse is located the following loads are to be taken:
.1 Below the deckhouse: Load pu according to the pressure head due to the distance between the supporting deck and the
deckhouse bottom [kN/m2
].
.2 Outside the deckhouse: Load pD.
.3 Bearing forces in accordance with the load assumptions 2.1 and 2.2.
3. Load cases
3.1 For design purposes the following load cases are to be investigated separately (see also Fig. 16.2) :
Fig. l6.2Design loads due to wind and water pressure
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-244-320.jpg)
![Section 16 - Superstructures and Deckhouses E 16-7/9
3.2 Service load cases
Forces due to external loads:
3.2.1Transverse direction (z-y-plane)
Py1 = G @ aβ(y) @ g + Pwi [kN]
acting in transverse direction
Pz1 = G @ aβ(z) @ g [kN]
acting vertically to the baseline
Pwi = wind load as per 2.2.2
aβ(y) = horizontal acceleration component of aβ
aβ(z) = vertical acceleration component of aβ.
3.2.2 Longitudinal direction (z-x-plane)
Px1 = G @ aβ(x) @ g + Pwa + Pwi [kN]
acting in longitudinal direction
Pz1 = G @ aβ(z) @ g [kN]
acting vertically to the baseline
aβ(x) = horizontal acceleration component in the longitudinal plane.
3.2.3For designing the securing devices to prevent the deckhouse from being lifted, the force (in upward direction) is not
to be taken less than determined from the following formula:
Pzmin = 0,5 @ g @ G [kN]
3.3 Extraordinary load cases
3.3.1Collision force in longitudinal direction:
Px2 = 0,5 @ g @ G [kN]
3.3.2Forces due to static heel of 45E
Pz2,Py2 = 0,71 @ g @ G [kN]
Pz2 = force acting vertically to the baseline
Py2 = force acting in transverse direction.
3.3.3The possible consequences of a fire for the elastic mounting of the deckhouse are to be examined (e.g. failure of rubber
elastic mounting elements, melting of glue). Even in this case, the mounting elements between hull and deckhouse bottom
shall be capable of withstanding the horizontal force Py2 as per 3.3.2 in transverse direction.
3.3.4For designing of the securing devices to prevent the deckhouse from being lifted, a force not less than the buoyancy
force of the deckhouse resulting from a water level of 2 m above the freeboard deck is to be taken.
4. Scantlings of rails, mounting elements and substructures
4.1 General
4.1.1The scantlings of those elements are to be determined in accordance with the load cases stipulated under 3. The effect
of deflection of main girders need not be considered under the condition that the deflection is so negligible that all elements
take over the loads equally.
4.1.2Strength calculations for the structural elements with information regarding acting forces are to be submitted for
approval.
4.2 Permissible stresses
4.2.1The permissible stresses given in Table 16.3 are not to be exceeded in the rails and the steel structures of mounting
elements and in the substructures (deck beams, girders of the deckhouse and the deck, on which the deckhouse is located).
4.2.2The permissible stresses for designing the elastic mounting elements of various systems will be considered from case
to case. Sufficient data are to be submitted for approval.
4.2.3The stresses in the securing devices to prevent the deckhouse from being lifted are not to exceed the stress values
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-245-320.jpg)
![E Section 16 - Superstructures and Deckhouses16-8/9
specified in 4.2.1.
4.2.4In screwed connections, the permissible stresses given in Table 16.4 are not to be exceeded.
Table 16.3 Permissible stress in the rails and the steel structures at mounting elements and in the substructures
[N/mm2
]
Type of stress
service load
cases
extraordinary
load cases
normal stress σn
0,6 @ ReH
or
0,4 @ Rm
0,75 @ ReH
or
0,5 @ Rm
shear stress τ
0,35 @ ReH
or
0,23 @ Rm
0,43 @ ReH
or
0,3 @ Rm
equivalent stress 0,75 @ ReH 0,9 @ ReH
ReH = minimum nominal upper yield point
Rm = tensile strength
4.2.5Where turnbuckles in accordance with DIN 82008 are used for securing devices, the load per bolt under load conditions
3.2.3 and 3.3.4 may be equal to the proof load (2 times safe working load).
5. Corrosion Addition
For the deck plating below elastically mounted deckhouse a minimum corrosion addition of tK = 3.0 mm applies.
Type of stress service load cases
extra-ordinary
load cases
longitudinal tension σn 0,5 @ ReH 0,8 @ ReH
bearing pressure pR 1,0 @ ReH 1,0 @ ReH
equivalent stress from longitudinal tension σn, tension τt
due to tightening torque and shear τ if applicable
0,6 @ ReH 1,0 @ ReH
F. Breakwater
1. Arrangement
If cargo is intended to be carried on deck forward of x/L $ 0,85, a breakwater or an equivalent protecting structure (e.g.
whaleback or turtle deck) is to be installed.
2. Dimensions of the breakwater
2.1 The recommended height of the breakwater is
hw = [mm]
but shall not be less than
hwmin = [mm]
where z is to be the vertical distance [m] between the summer load line and the bottom line of the breakwater.
The average height of whalebacks or turtle decks has to be determined analogously.
2.2 The breakwater has to be at least as broad as the width of the area behind the breakwater, intended for carrying
deck cargo.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-246-320.jpg)
![Section 16 - Superstructures and Deckhouses F 16-9/9
3. Cutouts
Cutouts in the webs of primary supporting members of the breakwater are to be reduced to their necessary minimum. Free
edges of the cutouts are to be reinforced by stiffeners.
If cutouts in the plating are provided to reduce the load on the breakwater, the area of single cutouts should not exceed 0,2
m2
and the sum of the cutout areas not
4. Loads
The loads for dimensioning are to be taken accordingly from C.2.
5. Plate thickness and stiffeners
5.1 The plate thickness has to be determined according to C.3.2.
5.2 The section moduli of the stiffeners are to be calculated according to C.3.1. Stiffeners are to be connected on both
ends to the structural members supporting them.
6. Primary supporting members
For primary supporting members of the structure a stress analysis has to be carried out.
Sufficient supporting structures are to be provided.
The permissible equivalent stress is σv = 230/k [N/mm2
].
7. Proof of buckling strength
Structural members' buckling strength has to be proved according to Section 3, F.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-247-320.jpg)
![Section 17 - Hatchways A 17-1/20
Section 17
Hatchways
A. General
1. Hatchways on freeboard and superstructure decks
1.1 The hatchways are classified according to their position as defined in Section 1, H.6.7.
1.2 Hatchways are to have coamings, the minimum height of which above the deck is to be as follows:
In position 1: 600 mm.
In position 2: 450 mm.
1.3 Adeviationfromtherequirementsunder1.2mayonlybegrantedforhatchwaysonexposeddeckswhichare closed
by weathertight, self tightening steel covers. The respective exemption, in accordance with IC LL Regulation 14(1), has
to be applied for in advance from the competent flag state authority.
1.4 Where an increased freeboard is assigned, the height of hatchway coamings according to 1.2 and the design load
for hatch covers according to Table 17.2 on the actual freeboard deck may be as required for a superstructure deck, provided
the summer freeboard is such that the resulting draught will not be greater than that corresponding to the minimum freeboard
calculated from an assumed freeboard deck situated at a distance equal to a standard superstructure height below the actual
freeboard deck.
1.5 For corrosion protection for all hatch coamings and all hatch covers of bulk carriers, ore carriers and combination
carriers, see Section 38, G.
Note
SpecialrequirementsofNationalAdministrationsregardinghatchways,hatchcovers, tighteningandsecuringarrangements
are to be observed.
2. Hatchways on lower decks and within superstructures
2.1 Coamings are not required for hatchways below the freeboard deck or within weathertight closed superstructures
unless they are required for strength purposes.
2.2 For hatchways according to 2.1 wooden gratings instead of hatch covers may be used; hatch covers may also be
dispensed with completely.
2.3 Where within hatch casings no hatchcoversare arrangedat thedecklevel,thenextcoversandtheirsupportsbelow
are to be strengthened corresponding to the greater load.
3. Definitions
p = design load [kN/m2
] for hatch covers of respective load cases A to D according to B.
= pH for vertical loading on hatch covers
= pA for horizontal loading on edge girders of hatch covers and on coamings
= liquid pressure p1, p2 according to Section 4,D.1.
ReH = minimum nominal upper yield point of the steel used [N/mm2
] according to Section 2,B.2.
For hatch covers the application of steel which minimum nominal upper yield point exceeds 355 N/mm2
is not permitted.
Rm = tensile strength of the steel used [N/mm2
]
For normal strength hull structural steel :
Rm = 400 N/mm2
with ReH = 235 N/mm2
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-249-320.jpg)
![A, B Section 17 - Hatchways17-2/20
For higher strength hull structural steel :
Rm = 440 N/mm² with ReH = 315 N/mm²
= 490 N/mm² with ReH = 355 N/mm²
R = unsupported span of stiffener [m]
a = spacing of hatchway beams or stiffeners [m]
t = thickness of structural member [mm]
= tnet + tK
tnet = net thickness [mm]
tK = corrosion addition according to Table 17.1.
B. Hatch Covers
1. Design loads
Structural assessment of hatch covers and hatch coamings is to be carried out according to the following design loads:
1.1 Load case A:
1.1.1The vertical design load pH for weather deck hatch covers is to be taken from Table 17.2 unless higher design loads
are requested by the owner.
1.1.2The design load for hatch covers of decks the height of which above baseline is z > zfb + 2 @ hN may be reduced, if the
Administration concerned agrees and if it is verified that the load capacity of the hatch cover corresponds at least to that of
the deck beside.
zfb = required height of the freeboard deck above baseline [m] according to ICLL
hN = superstructure standard height according to ICLL
= [m] for
1.1.3 The vertical design load pH shall in no case be less than the deck design load according to Section 4, B.1. Instead
of the deck height z the height of hatch cover plating above baseline is then to be inserted.
1.1.4 The horizontal design load pA for the outer edge girders of weather deck hatch covers and of hatch coamings is
to be determined analogously as for superstructure walls in the respective position.
For bulk carriers according to Section 23 the horizontal load shall not be less than:
PAmin = 175 kN/m2
in general for outer edge girders of hatch covers
= 220 kN/m2
in general for hatch coamings
= 230 kN/m2
for the forward edge girder of the hatch 1 cover, if no forecastle according to Section
23, D is arranged
= 290 kN/m2
for the forward transverse coaming of hatch 1, if no forecastle according to Section
23, D is arranged
1.2 Load case B:
Where cargo is intended to be carried on hatch covers of decks in pos. 1 and 2 hatch covers, they are to be designed for the
loads as given in Section 4, C.1.
If cargo with low stowage height is carried on weather deck hatch covers Section 4, B.13 is to be observed.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-250-320.jpg)
![Section 17 - Hatchways B 17-3/20
Table 17.1 - Corrosion addition for hatch coamings and hatch covers
Application Structure tK (mm)
Weather deck hatches of container
ships, car carriers, paper carriers,
passenger vessels
Hatch covers:
- Weather exposed plating
- Remaining structure
1,3
1,0
Hatch coamings according to Section 3, K.1.
Weather deck hatches of all other ship
types (e.g. multi-purpose dry cargo
ships)
Hatch covers in general: Load Case A,D Load Case B,C,E1
- weather exposed plating 2,0 1,5
- remaining structure 2,0 1,2
Double skin hatch covers and closed
box girders
- weather exposed plating and
bottom plating
1,5 (2,0)2
- inner structures 1,0 (1,5)2
- remaining structures 1,2
Hatch coamings not part of the
longitudinal hull structure
1,5
Hatch coamings part of the
longitudinal hull structure
according to Section 3, K.1.
Coaming stays and stiffners 1,5
Hatches within enclosed spaces
Hatch covers :
- top plating 1,2
- remaining structures 1,0
Hatch covers and coamings according to Section 3, K.1. to K.3.
1)
The tk-values for load case A, B, C and E respectively are to be indicated in the drawings.
2)
The tk-values in brackets are to be applied to bulk carriers according to the definition of IACS Common Structural
Rules (See Section 23, B.1.4)
1.3 Load case C:
Where containers, which are not horizontally supported, are stowed on hatch covers of hatch in pos. 1 and 2 the following
loads due to the ship's rolling motion are to be considered, see also Fig. 17.1.
Az = 9,81 @ (1 + av) [kN]
Bz = 9,81 @ (1 + av) [kN]
By = 2,4 @ M [kN]
av = acceleration factor according to section 4,C.1
M = mass of container stack [t]
hm = height of centre of gravity of stack above hatch cover supports [m]
For M and hm those values shall be used, which are calculated using non reduced acceleration values according to Rules
for Stowage and Lashing of Containers, Section 3, A.
b = distance between footpoints [m]
Az, Bz, By = support forces in y-, z- direction at the stack corners.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-251-320.jpg)
![B Section 17 - Hatchways17-4/20
Table 17.2 - Design load of weather deck hatches
Position
Design load pH [kN/m2
]
1
for m
for m
9,81 @ 3,5
for type B ships according to ICLL
for ships with less freeboard then type B ships according to ICLL
, with
2
for m
for m
9,81 @ 2,6 9,81 @ 3,5
Fig. 17.1 Forces due to load case C acting on hatch cover
1.3.1Load cases with partial loading
TheloadcasesBandC arealsotobeconsidered forpartialloadingwhichmayoccurinpractice,e.g.wherespecifiedcontainer
stack places are empty.
The design load for other cargo than containers subject to lifting forces is to be determined separately.
1.3.2 In case of container stacks secured to lashing bridges or carried in cell guides the forces acting on the hatch cover
are to be considered.
1.4 Load case D:
Hatch covers of hold spaces intended to be filled with liquids are to be designed for the loads specified in Section 4, D.1.
and D.2. irrespective of the filling height of hold spaces.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-252-320.jpg)
![Section 17 - Hatchways B 17-5/20
1.5 Load case E:
Hatch covers, which in addition to the loads according to 1. are loaded in the ship's transversedirectionbyforcesduetoelastic
deformations of the ship's hull, are to be so designed that the sum of stresses does not exceed the permissible values given
in 2.
1.6 Load case F:
Tweendeck hatch covers not subject to cargo loads are to be designed for a uniformly distributed load of 2 kN/m2
or for a
single load of 3 kN, whichever results in the stronger scantlings.
1.7 Horizontal mass forces
For the design of the securing devices against shifting according to 4.7 the horizontal mass forces in ship's longitudinal
and transverse direction are to be calculated. For this purpose the following acceleration component are to be used:
ax = 0,2 @ g [m/s2
] in longitudinal direction
ay = 0,5 @ g [m/s2
] in transverse direction
2. Permissible stresses and deflections
2.1 The equivalent stress in steel hatch cover structures related to the net thickness shall not exceed 0,8 .
ReH.v
[N/mm2
]
F =
Fb = bending stress
Fn = normal stress
J = shear stress
The deflection f of weather deck hatch covers under the design load pH shall not exceed
f = 0,0056 Rg
Rg = largest span of girders [m]
Note :
Where hatch covers are arranged for carrying containers and mixed stowage is allowed i.e. a 40'-container on stowages
places for two 20'-containers, the deflections of hatch covers have to be particularly observed.
2.2 Where hatch covers are made of aluminium alloys. Section 2, D. is to be observed. For permissible deflections
2.1 applies.
2.3 Thepermissiblestressesspecifiedunder2.1applytoprimarygirdersofsymmetricalcrosssection.Forunsymmetrical
cross sections, e.g. - sections, equivalence in regard to strength and safety is to be proved, see also Section 3, L.
3. Strength calculation for hatch covers
3.1 General
Calculations are to be based on net thickness:
The tK values used for calculation have to be indicated in the drawings.
Verifications according to Section 3, F. are to be based on t = tnet and stresses corresponding to tnet applying the safety factor
S = 1,1.
Forallstructuralcomponentsofhatchcoversforspacesinwhichliquidsarecarried,theminimumthicknessfortanksaccording
to Section 12, A.7. is to be observed.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-253-320.jpg)
![B Section 17 - Hatchways17-6/20
3.2 Hatch cover supports
Supports and stoppers of hatch covers are to be so arranged that no constraints due to hull deformations occur in the hatch
cover structure and at stoppers respectively, see also load case E.
Deformations due to the design loads according to 1. between coaming and weathertight hatch covers, as well as between
coaming and covers for hold spaces in which liquids are carried, shall not lead to leakiness.
Iftwoormoredeckpanels are arranged on one hatch, clearancesinforcetransmittingelementsbetweenpanelshavegenerally
to be observed.
For bulk carriers according to Section 23 each panel has to be assumed as independently load-bearing.
Stiffness of securing devices, where applicable, and clearances are to be considered.
3.3 Strength calculations for beam and girder grillages
Cross-sectional properties are to be determined considering the effective breadth according to Section 3, E. Cross sectional
areas of profiles parallel to the girder web within the effective breadth can be included, see Section 3, F.
The effective width of flange plates under compression with stiffeners perpendicular to the girder web is to be determined
according to Section 3, F.2.2.
In way of larger cutouts in girder webs it may be required to consider second order bending moments.
3.4 FEM calculations
Forstrengthcalculationsofhatchcoversbymeansoffiniteelements,thecovergeometryshallbeidealisedbuiltasrealistically
as possible. Element size shall be appropriate to account for effective breadth. In no case element width shall be larger than
stiffener spacing. In way of force transfer points and cutouts the mesh has to be refined where applicable.
The ratio of element length to width shall not exceed 2.
The element height of girder webs shall not exceed half the web height.
Stiffeners, supporting plates against lateral loads, have to be included in the idealization.
Buckling stiffeners may be disregarded for the stress calculation.
4. Scantlings
4.1 Hatch cover plating
4.1.1Top plating
The thickness of the hatch cover top plating is to be obtained from the calculation according to 3. However, the thickness
shall not be less than the largest of the following values :
t = [mm]
= [mm]
t = [mm]
tmin = 6,0 mm
cp = for p = pH
= for p from pD, cargo load or liquid pressure
Fx = bending stress [N/mm2
] of main girder at a distance a/2 of the girder web, see Section 3, F.
For flange plates under compression sufficient buckling strength according to Section 3, F. is to be verified.
For hatch covers subject to wheel loading plate thickness shall not be less than according to Section 7, B.2.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-254-320.jpg)
![Section 17 - Hatchways B 17-7/20
4.1.2Lower plating of pontoon hatch covers and box girders
The thickness is to be obtained from the calculation according to 3.
The thickness shall not be less than the larger of the following values :
t = [mm]
tmin = 6,0 mm
The lower plating of hatch covers for spaces in which liquids are carried is to be designed for the liquid pressure and the
thickness is to be determined according to 4.1.1.
4.2 Main girders
Scantlingsofmaingirdersareobtainedfromthecalculationaccordingto3.underconsiderationofpermissiblestressesaccording
to 2.
For all components of main girders sufficient safety against bucklingshallbeverified. For biaxially compressed flange plates
thisistobeverifiedwithintheeffectivewidths.Atintersectionsofflangesfromtwogirders,notchstresseshavetobeobserved.
The thickness of main girder webs shall not be less than :
t = [mm]
tmin = 6,0 mm
For hatch covers of bulk carriers according to Section 23 the ratio of flange width to web height shall not exceed 0,4, if the
unsupportedlengthoftheflangebetween two flange supports of main girders is largerthan3,0m. Theratioofflangeoutstand
to flange thickness shall not exceed 15.
4.3 Edge girders
4.3.1 Scantlingsofedgegirders are obtained fromthe calculationsaccordingto3.Thethicknessoftheouteredge girders
exposed to wash of sea shall not be less than the largest of the following values :
t = [mm]
= [mm]
t = [mm]
tmin = 6,0 mm
4.3.2 The stiffness of edge girders of weather deck hatch covers is to be sufficient to maintain adequate sealing pressure
between securing devices. The moment of inertia of edge elements is not to be less than:
I = [cm4
]
q = packing line pressure [N/mm], minimum 5 N/mm
s = spacing [m] of securing devices
4.3.3 For hatch covers of spaces in which liquids are carried, the packing line pressure shall also be ensured in case
of hatch cover loading due to liquid pressure.
4.4 Hatch cover stiffeners
The section modules Wnet and shear area Asnet of uniformly loaded hatch cover stiffeners constraint at both ends shall not
be less than :
[cm3
]
[cm2
]
Stiffeners paralleltomaingirderwebsandarrangedwithintheeffectivebreadth according to Section 3, E. shall be continuous
at transverse girders and may be regarded for calculating the cross sectional properties of main girders. It is to be verified
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-255-320.jpg)
![B Section 17 - Hatchways17-8/20
that the resulting stress from main girders and hatch cover stiffeners does not exceed the permissible stress according to 2.
If hatch cover stiffeners are sniped at the edge girders, Wnet is to be increased by 50 %
The thickness of hatch cover plating at sniped stiffener ends shall not be less than the thickness according to Section 3,
D.3.
For hatch cover stiffeners under compression sufficient safety against lateral and torsional buckling according to Section
3, F. is to be verified.
For hatch covers subject to wheel loading stiffener scantlings are to be determined by direct calculations.
4.5 Hatch cover supports
4.5.1Hatch covers, which are intended to carry cargo, are to be additionally secured against shifting in the longitudinal and
transverse direction due to the acting mass forces specified in 1.7.
For the transmission of the support forces resulting from the load cases specified in 1.1 - 1.7, supports are to be provided
which are to be designed such that the nominal surface pressures in general do not exceed the following values:
pn max = [N/mm2
]
d =
dmax = 3,0
dmin = 1,0 in general
= 2,0 for partial loading conditions (see 1.3.1)
pn = see Table 17.3
Table 17.3 - Permissible nominal surface pressure pn
Support material
pn [N/mm2
]
when loaded by
Vertical force Horizontal force
hull structural steels 25 40
hardened steels 35 50
plastic materials on steel 50 -
For metallic supporting surfaces not subjected to relative displacements the following applies:
pn max = 3 @ pn [N/mm2
]
Where large relative displacements of the supporting surfaces are to be expected, the use of material having low wear and
frictional properties is recommended.
4.5.2Drawings of the supports shall be submitted. In the drawings of the supports the permitted maximum pressure given
by the material manufacturer related to long time stress is to be specified.
4.5.3If necessary, sufficient abrasive strength may be shown by tests demonstrating an abrasion of support surfaces of not
more than 0,3 mm per one year in service at a total distance of shifting of 15 000 m/year.
4.5.4The substructures of the supports have to be of such a design, that a uniform pressure distribution is achieved.
4.5.5Irrespectiveofthearrangementofstoppers,thesupportsshallbeabletotransmitthefollowingforcePh inthelongitudinal
and transverse direction:
Ph = [kN]
Pv = vertical supporting force [kN].
: = frictional coefficient
= 0,5 for steel on steel
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-256-320.jpg)
![Section 17 - Hatchways B 17-9/20
= 0,35 for non-metallic, low-friction support materials on steel
4.5.6Supports,aswellastheadjacentstructuresandsubstructuresaretobedesignedsuch thatthepermissibelstressesaccording
to 2. are not exceeded.
4.5.7For substructures and adjacent constructions of supports subjected to horizontal forces Ph a fatigue strength analysis
is to be carried out according to Section 20 by using the stress spectrum B and applying the horizontal force Ph.
4.6 Locking and securing of hatch covers
4.6.1Securing of weather deck hatch covers
4.6.1.1 Locking devices between cover and coaming and at cross-joints are to be provided to ensure weathertightness.
Sufficient packing line pressure is to be maintained. The packing line pressure is to be specified in the drawings.
Securing devices shall be appropriate to bridge displacements between cover and coaming due to hull deformations.
4.6.1.2 Securing devices are to be of reliable construction and effectively attached to the hatchway coamings, decks or
covers. Individual securing devices on each cover are to have approximately the same stiffness characteristics.
4.6.1.3 Where rod cleats are fitted, resilient washers or cushions are to be incorporated.
4.6.1.4 Where hydraulic cleating is adopted, a positive means is to be provided to ensure that it remains mechanically
locked in the closed position in the event of failure of the hydraulic system.
4.6.1.5 The spacing of securing devices shall generally not exceed 6 m.
4.6.1.6 Securing devices are to be provided at each corner of the hatch cover. This applies also to hatch covers consisting
of several parts.
4.6.1.7 The net cross-sectional area of the securing devices is not to be less than:
A = [cm2
]
q = packing line pressure [N/mm], minimum 5 N/mm
s = spacing between securing devices [m], not to be taken less than 2 m
=
ReH is not to be taken greater than 0,70 Rm.
e = 0,75 for ReH > 235 N/mm²
= 1,00 for ReH # 235 N/mm²
Rods or bolts are to have a net diameter not less than 19 mm for hatchways exceeding 5 m2
in area.
4.6.1.8 Thelockingelementsofhatchcovers,onwhichcargoistobelashed,aretobedesignedfortheliftingforcesaccording
to 1., load case C. Unsymmetrical loadings, which may occur in practice, are to be considered. Under these loadings the
equivalent stress in the securing devices is not to exceed:
= [N/mm2
]
4.6.1.9 Securing devices of hatch covers for spaces in which liquids are carried shall be designed for the lifting forces
according to load case D.
4.6.1.10 Cargo deck hatch covers consisting of several parts have to be secured against accidental lifting.
4.7 Hatch cover stoppers
Hatch covers shall be sufficiently secured against shifting.
Stoppers are to be provided for hatch covers on which cargo is carried as well as for hatch covers, which edge girders have
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-257-320.jpg)
![B Section 17 - Hatchways17-10/20
to be designed for pA > 175 kN/m2
.
Design forces for the stoppers are obtained from the loads according to 1.
The permissible stress in stoppers and their substructures in the cover and of the coamings is to be determined according
to 2.
4.8 Cantilevers, load transmitting elements
4.8.1Cantilevers and load transmitting elements which are transmitting the forces exerted by hydraulic cylinders into the
hatchway covers and the hull are to be designed for the forces stated by the manufacturer. The permissible stresses according
to 2. are not to be exceeded.
4.8.2Structuralmemberssubjectedtocompressivestressesaretobeexaminedforsufficientsafetyagainstbuckling,according
to Section 3, F.
4.8.3Particular attention is tobepaidtothe structural design in way of locations where loads are introduced into the structure.
4.9 Container seatings on hatch covers
The seatings and their substructures are to be designed for the loads according to load case B and C respectively, applying
the permissible stresses according to 2.
5. Weathertightness of hatch covers
For weather deck hatch covers packings are to be provided, exception see 5.2
5.1 Packing material
5.1.1The packing material is to be suitable for all expected service conditions of the ship and is to be compatible with the
cargoes to be transported.
The packing material is to be selected with regard to dimensions and elasticity in such a way that expected deformations
can be carried. Forces are to be carried by the steel structure only.
The packings are to be compressed so as to give the necessary tightness effect for all expected operating conditions.
Special consideration shall be given to the packing arrangementin ships with large relative movements betweenhatch covers
and coamings or between hatch cover sections.
5.1.2If the requirements in 5.2 are fulfilled the weather tightness can be dispensed with.
5.2 Non-weathertightness hatch covers
5.2.1Upon request and subject to compliance with the following conditions the fitting of weather tight gaskets according
to 5.1 may be dispensed with:
5.2.1.1 The hatchway coamings shall be not less than 600 mm in height.
5.2.1.2 The hatch covers are located above a depth H(x).
H(x) is to be shown to comply with the following calculated criteria:
H(x) $ Tfb + fb + hN + 4,6 [m]
Tfb = draught corresponding to the assigned summer load line
fb = freeboard determined in accordance with ICLL, relative to a deck height which is by hN + 4,6 m smaller
than H(x)
hN = 0 for # 0,75 [m]
= 2,3 for > 0,75 [m]
5.2.1.3 Labyrinths are to be fitted proximate to the edges of each panel in way of the coamings. The clear profile of these
openings is to be kept as small as possible.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-258-320.jpg)
![Section 17 - Hatchways B 17-11/20
Where a hatch is covered by several hatch cover panels the clear opening of the gap in between the panels shall be not wider
than 50 mm.
Thelabyrinthsandgapsbetweenhatchcoverpanelsshallbeconsideredasunprotectedopeningswithrespecttotherequirements
of intact and damage stability calculations.
Withregardtodrainageofcargoholdsandthenecessaryfire-fightingsystemreferenceismadetoRulesforMachineryInstallations,
Volume III, Sections 11 and 12.
Furthermore, the requirements for the carriage of dangerous goods are to be complied with.
5.2.2 Securing devices
In the context of paragraph 5.2 an equivalence to 4.6 can be considered subject to:
– the proof that in accordance with 1.3 load case C securing devices are not to be required and additionally
– the transverse cover guides are effective up to a height hE above the cover supports. The height hE shall not be less than
the greater of the following formulae:
hE = 1, 75 @ [mm]
hEmin = height of the face plate [mm] + 150
where
e = largest distance of the cover guides from the longitudinal face plate [mm]
s = total clearance [mm]
with
10 < s < 40
The transverse guides and their substructure are to be dimensioned in accordance with the loads given in 1.7 acting
at the position hE using the equivalent stress level Fv = ReH [N/mm2
].
5.3 Drainage arrangements
5.3.1 If drain channels are provided inside the line of gasket by means of a gutter bar or vertical extension of the hatch
side and end coaming, drain openings are to be provided at appropriate positions of the drain channels.
5.3.2 Drain openings in hatch coamings are to be arranged with sufficient distance to areas of stress concentration (e.g.
hatch corners, transitions to crane posts).
5.3.3 Drain openings are to be arranged at the ends of drain channels and are to be provided with non-return valves to
prevent ingress of water from the outside. Lengths of fire hoses are not acceptable.
5.3.4Cross-joints of multi-panel covers are to be provided with efficient drainage arrangements.
5.3.5If a continuous outer steel contact between cover and ship structure is arranged, drainage from the space between the
steel contact and the gasket is also to be provided for.
5.4 Tightness test, trials
5.4.1The self-tightening steel hatch coversonweather decks and within open superstructures are to be hose tested. The water
pressure should not be less than 2 bar and the hose nozzle should be held at a distance of not more than 1,5 m from the hatch
cover to be tested. The nozzle diameter should not be less than 12 mm. During frost periods equivalent tightness tests may
be carried out to the satisfaction of the Surveyor.
5.4.2Upon completion of the hatchway cover system trials for proper functioning are to be carried out in presence of the
Surveyor.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-259-320.jpg)
![B Section 17 - Hatchways17-12/20
6. Wooden hatchway covers & hatchway beams
6.1 Hatchway covers
6.1.1The thickness of woodenhatchcoversisnottobeless than60mmwhere the spacing of hatchway beams is 1,5 m. Where
the beams spacing is greater or smaller than 1,5 m, the thickness of the covers is modified proportionally; however, it is not
to be less than 50 mm.
6.1.2Where the 'tween deck height exceeds 2,5 m, or the deck load is greater than 1,8 t/m2
, the thickness of the hatch covers
is to be increased at the rate of 12 mm per 1 m greater 'tween deck height, or per 0,72 t/m2
increased in deck load.
6.1.3The grovers for grips are not be arranged too near to the ends of the hatch covers.
6.1.4The wood used for the hatch coverings is to be of good quality, free from sap and objectionable defects, and dry.
6.1.5The ends of wood hatch covers shall be encircled by durable bands, e.g., of galvanized steel.
6.2. Hatchway beams
6.2.1General
6.2.1.1 Hatchwaybeamsmaybeconstructedeitherasslidingbeamsorasboltedbeams.Slidingbeamsarehatchwaybeams
movable in the longitudinal hatchway direction, whereas bolted beams are fixed to the longitudinal coaming.
6.2.1.2 The scantlings ofpontoonhatchcoversfittedwithtarpaulinsandbatteningdevices used inlieuofhatchway beams
and wooden hatch covers are to be determined as for hatchway beams.
6.2.1.3 The scantlings of pontoon hatch covers in 'tweendecks may be determined as for steel hatch covers according to
4.1.
The same applies to portable beams (herfts) of 'tweendeck hatchways if they are constructed as box girders.
6.2.2Scantlings
6.2.2.1 Thesectionmodulusandthemomentofinertiaofhatchwaybeamssimplysupportedatbothendsaretobedetermined
according to 6.3. For hatchway beams designed by direct calculations, 2.1 is to be observed.
6.2.2.2 The web thickness of hatchway beams is not be less than:
t = 6 + [mm]
tmin = 7,5 [mm]
6.2.2.3 In general, the web depth is not to be less than 150 mm.
6.2.2.4 The width of the beam face plate is to be sufficient to provide a minimum bearing surface for the hatch covers
of 65 mm.
6.2.2.5 At beams which carry the ends of hatch covers the web plate is to extend 50 mm above the upper edge of the top
flange, or flat bars of 50 mm in height are to be welded on the top flanges.
6.2.2.6 The upper face plates are to be extended to the extreme ends of the beams. For sliding beams which are supported
on the edge of the coaming, on the deck, or on slide angles, also the lower face plates are to be extended to the ends of the
beams.
6.2.2.7 At their ends the face plates are to be connected by continuous fillet welds to the webs at a length equal to 1,5
times the depth of web.
6.2.2.8 At the ends of bolted beams, which are supported by carriers of double angles, strengthened web plates are to be
fitted, having a breadth of at least 180 mm.
6.2.2.9 Lightening holes or lifting holes are not to be provided within 0,5 m from either ends.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-260-320.jpg)
![Section 17 - Hatchways B 17-13/20
6.3. Moments of inertia, section moduli, shear areas
6.3.1Thesection modulusofsteelhatchwaybeamsandhatchcoverstiffenerswhichmayberegardedasbeingsimplysupported
at both ends is not to be less than :
W = [cm3
]
= permissible bending stress =
The moment of inertia of steel hatchway beams of hatches in pos. 1 and 2 which may be regarded as being simply supported
is not to be less than:
I = C2 @ C3 @ a @ R3
@ pH [cm4
]
C1 = 1 +
C1min = 1,0
" =
( =
For R, R1, W, W1, I, I1 see Fig. 17.2
C2 = 2,82 for hatchway beams
= 2,22 for hatch cover stiffeners
C3 = 1 + 8"3
$ =
Fig. 17.2
6.3.2 Within 0,1 R from supports the web sectional area is not to be less than :
Aw = [cm2
]
6.4 Arrangement and securing of hatchway beams
6.4.1The beam spacing is to be equal throughout a hatchway. Where the spacings are unequal, the difference is to be such
that the shorter hatch covers cannot be used for the greater intervals.
6.4.2Hatchway beams are to be provided with an efficient device for locking them in their positions. Locking bolts are to
have a diameter of at least 22 mm.
6.4.3The beams are to have a bearing surface of at least 75 mm. The thickness of supporting angles is not to be less than
12 mm. The connection of the support to the coaming is to be in proportion to the hatchway beams.
6.4.4The ends of the sliding beams are to be so designed that they cannot fall down when being moved along the coaming.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-261-320.jpg)
![Section 17 - Hatchways C 17-15/20
2. Scantlings
2.1 Plating
The thickness of weather deck hatch coamings shall not be less than the larger of the following values:
t = [mm]
= [mm]
tmin = [mm]
L need not be taken greater than 300 m
tmin = 9,5 + tK [mm] for bulk carrier according to Section 23.
For grab operation see also Section 23, B.9.1.
2.2 Coaming stays
2.2.1 Coaming stays are to be designed for the loads and permissible stresses according to B.
2.2.2 The section modulus of coaming stays of coamings, the height of which is hs < 1,6 m and which are to be designed
for the load pA, shall not be less than :
= [cm3
]
e = spacing of coaming stays [m]
The effective breadth of the coaming plate shall not be larger than the effective plate width according to Section 3, F.2.
Coaming stays are to be supported by appropriate substructures.
Face plates may only be includedinthecalculationifanappropriatesubstructureisprovidedand welding ensures an adequate
joint.
2.2.3 Web thickness at the root point shall not be less than :
= [mm]
= [mm]
hw = web height of coaming stay at root point [m]
Webs are to be connected to the decks by fillet welds on both sides with a = 0,44 @ tw. For toes of stay webs within 0,15 @
hw the throat thickness is to be increased to a = 0,7 @ tw for tw # 10 mm. For tw > 10,0 mm deep penetration double bevel
welds are to be provided in this area.
2.2.4 For coaming stays, which transfer friction forces at hatch cover supports, sufficient fatigue strength according
to Section 20 is to be verified.
2.3 Horizontal stiffeners
The stiffeners shall be continuous at the coaming stays.
For stiffeners with both ends constraint the elastic section modulus Wnet and shear area Asnet, calculated on the basis of net
thickness, shall not be less than:
Wnet = [cm3
]
Anet = [cm2
]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-263-320.jpg)
![Section 17 - Hatchways D 17-17/20
above the summer load waterline, whichever is the lesser.
2.3 Strength
2.3.1 Forsmallrectangularsteelhatchcovers,theplatethickness,stiffenerarrangementandscantlingsaretobein accordance
with Table 17.4 and Fig. 17.3. Stiffeners, where fitted, are to be aligned with the metal-to-metal contact points, required in
2.5.1, see Fig. 17.3. Primary stiffeners are to be continuous. All stiffeners are to be welded to the inner edge stiffener, see
Fig. 17.4.
2.3.2 The upper edge of the hatchway coamings is to be suitably reinforced by a horizontal section, normally not more
than 170 mm to 190 mm from the upper edge of the coamings.
2.3.3 For small hatch covers of circular or similar shape, the cover plate thickness and reinforcement is to be specially
considered.
2.3.4 For small hatch covers constructed of materials other than steel, the required scantlings are to provide equivalent
strength.
Table 17.4 - Scantlings for small steel hatch covers on the fore deck
Nominal size
[mm x mm]
Cover plate
thickness [mm]
Primary stiffeners Secondary stiffeners
Flat bar [mm x mm]; number
630 x 630 8 -- --
630 x 830 8 100 x 8; 1 --
830 x 630 8 100 x 8; 1 --
830 x 830 8 100 x 10; 1 --
1030 x 1030 8 120 x 12; 1 80 x 8; 2
1330 x 1330 8 150 x 12; 2 100 x 10; 2
For ships with L < 80 m the cover scantlings may be reduced by the factor :
$ 0,75
2.4 Primary securing devices
2.4.1 Small hatches located on exposed fore deck subject to theapplication according to 2.2 are to be fitted with primary
securing devices such that their hatch covers can be secured in place and weathertight by means of a mechanism employing
any one of the following methods:
– method A : butterfly nuts tightening onto forks (clamps)
– method B : quick acting cleats
– method C : central locking device
2.4.2 Dogs (twist tightening handles) with wedges are not acceptable.
2.5 Requirements for primary securing
2.5.1 The hatch cover is to be fitted with a gasket of elastic material. This is to be designed to allow a metal to metal
contactatadesignedcompressionandtopreventover-compressionofthegasketbygreenseaforcesthatmaycausethesecuring
devicestobeloosenedordislodged.Themetal-to-metalcontactsaretobearrangedclosetoeachsecuringdeviceinaccordance
with Fig. 17.3 and of sufficient capacity to withstand the bearing force.
2.5.2 The primary securing method is to be designed and manufactured such that the designed compression pressure
is achieved by one person without the need of any tools.
2.5.3 For a primary securing method using butterfly nuts, the forks (clamps) are to be of robust design. They are to be
designed to minimize the risk of butterfly nuts being dislodged while in use; by means of curving the forks upward, a raised
surface on the free end, or a similar method. The plate thickness of unstiffened steel forks is not to be less than 16 mm. An
example arrangement is shown in Fig. 17.4.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-265-320.jpg)
![Section 18 - Equipment A, B 18-1/10
Section 18
Equipment
A. General
1. The equipment of anchors. chain cables, wires and ropes is to be determined from Table 18.2 in accordance with
the equipment numeral Z1 or Z2, respectively.
Note
The anchoring equipment required by this Section is intended of temporary mooring of a vessel within a harbour or
sheltered area when the vessel is awaiting berth, tide, etc.
The equipment is, therefore, not designed to hold a ship off fully exposed coasts in rough weather or to stop a ship which
is moving or drifting. In this condition the loads on the anchoring equipment increase to such a degree that its components
may be damaged or lost owing to the high energy forces generated, particularly in large ships.
The anchoring equipment required by this Section is designed to hold a ship in good holding ground in conditions such as
to avoid dragging of the anchor. In poor holding ground the holding power of the anchors will be significantly reduced.
The equipment numeral formula for anchoring equipment required under this Section is based on an assumed current speed
of 2,5 m/sec, wind speed of 25 m/sec and a scope of chain cable between 6 and 10, the scope being the ratio between length
of chain paid out and water depth.
It is assumed that under normal circumstances a ship will use only one bow anchor and chain cable at a time.
2. Every ship is to be equipped with at least one anchor windlass.
Windlass and chain stopper, if fitted, are to comply with Rules for Machinery Installations, Volume III, Section 14,D.
For the substructures of windlasses and chain stoppers, see Section 10, B.5.
For the location of windlasses on tankers, see Section 24, A.9.
3. For ships having the navigation Notation "L" (Coasting Service) affixed to their Character of Classification, the
equipment may be determined as for one numeral range lower than required in accordance with the equipment numeral Z1
or Z2, respectively.
4. When determining the equipmentforshipshavingthenavigationnotation"T"(Sheltered Shallow Water Service)
affixed to their Character of Classification, the provisions of Section 30, E. are to be observed.
5. When determining the equipment for tugs, Section 27, E. is to be observed.
When determining the equipment of barges and pontoons, Section 31, G. is to be observed.
6. Ships built under survey of BKI and which are to have the mark a stated in their Certificate and in the Register
Book must be equipped with anchors and chain cables complying with the Rules for Materials, Volume V, and having been
tested on approved machines in the presence of Surveyor.
7. For ships having three or more propellers, a reduction of the weight of the bower anchors and the chain cables
may be considered.
B. Equipment Numeral
1. The equipment numeral Z1 for anchors and chain cables is to be calculated as follows :
Z1 =
D = moulded displacement [ton] (in sea water having a density of 1,025 t/m3
) to the summer load waterline
h = effective height from the summer load waterline to the top of the uppermost house
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-269-320.jpg)
![B, C Section 18 - Equipment18-2/10
= a + Ghi
a = distance [m], from the summer load water-line, amidships, to the upper deck at side
A = area [m2
], in profile view of the hull, superstructures and houses, having a breadth greater than B/4, above
the summer load waterline within the length L and up to the height h
3hi = sum of height [m] of superstructures and deckhouses, measured on the centreline of each tier having a
breadth greater than B/4. Deck sheer, if any, is to be ignored. For the lowest tier, "h" is to be measured at
centreline from the upper deck or from a notional deck line where there is local discontinuity in the upper
deck.
Where a deckhouse having a breadth greater than B/4 is located above a deckhouse having a breadth of B/4 or less, the wide
house is to be included and the narrow house ignored.
Screens of bulwarks 1,5 m or more in height are to be regarded as parts of houses when determining h and A, e.g. the area
shown in Fig. 18.1 as A1 is to be included in A. The height of the hatch coamings and that of any deck cargo, such as
containers, may be disregarded when determining h and A.
Fig. 18.1 Effective area A1 of bulwark
2. The equipment numeral Z2 for the recommended selection of ropes as well as for the determination of the design
load for shipboard towing and mooring equipment and supporting hull structure is to be calculated as follows:
Z2 =
D = moulded displacement [t] in sea water having a density of 1,025 t/m3
to the summer load waterline
h = effective height from the summer load waterline to the top of the uppermost house
= a + Ehi
a = distance [m], from the summer load waterline, amidships, to the upper deck at side
Ehi = sum of height [m] of superstructures and deckhouses on the upper deck, measured on the centreline of each
tier. Deck sheer, if any, is to be ignored. For the lowest tier, "h" is to be measured at centreline from the
upper deck or from a notional deck line where there is local discontinuity in the upper deck.
A = area [m2
], in profile view of the hull, superstructures and deckhouses above the summer load waterline
within the length L.
Screens of bulwarks, hatch coamings and deck equipment, e.g., masts and lifting gear, as well as containers
on deck have to be observed for the calculation of A.
C. Anchors
1. The number of bower anchors is to be determined according to column 3 of Table 18.2. The anchors are to be
connected to their chain cables and positioned on board ready for use.
It is to be ensured that each anchor can be stowed in the hawse and hawse pipe in such a way that it remains firmly secured
in seagoing conditions. Details have to be coordinated with the owner.
Note
National regulations concerning the provision of a spare anchor, stream anchor or a stern anchor may need to be observed.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-270-320.jpg)
![D, E Section 18 - Equipment18-4/10
strength Rm of not less than 400 N/mm2
.
3. Grade K 2 and K 3 chain cables shall be post production quenched and tempered and purchased from recognized
manufacturers only.
4. The total length of chain given in the Table 18.2 is to be divided in approximately equal parts between the two
bower anchors.
5. Either stud link or short link chain cables may be used for stream anchors.
6. For connection of the anchor with the chain cable approved Kenter-type anchor shackles may be chosen in lieu
of the common Dee-shackles. A forerunner with swivel is to be fitted between anchor and chain cable. In lieu of a forerunner
with swivel an approved swivel shackle may be used. However, swivel shackles are not to be connected to the anchor shank
unless specially approved. A sufficient number of suitable spare shackles are to be kept on board to facilitate fitting of the
spare anchor at any time. On owner's request the swivel shackle may be dispensed with.
7. The attachment of the inboard ends of the chain cables to the ship's structure is to be provided with a mean
suitable to permit, in case of emergency, an easy slipping of the chain cables to sea operable from an accessible position
outside the chain locker.
The inboard ends of the chain cables are to be secured to the structures by a fastening able to withstand a force not less than
15% nor more than 30% of the rated breaking load of the chain cable.
E. Chain Locker
1. The chain locker is to be of capacity and depth adequate to provide an easy direct lead of the cables through the
chain pipes and self-stowing of the cables.
The minimum required stowage capacity without mud box for the two bow anchor chains is as follows:
[m3
]
d = chain diameter [mm] according to Table 18.2
R = total length of stud link chain cable according to Table 18.2
The total stowage capacity is to be distributed on two chain lockers of equal size for the port and starboard chain cables.
The shape of the base areas shall as far as possible be quadratic with a maximum edge length of 33 d. As an alternative,
circular base areas may be selected, the diameter of which shall not exceed 30 – 35 d.
Above the stowage of each chain locker sufficient free depth is to be provided
2. The chain locker boundaries and their access openings are to be watertight to prevent flooding of essential
installation or equipment are aranged, in order to not affect the proper operation of the ship after accidental flooding of the
chain locker.
2.1 Special requirements to minimize the ingress of water
2.1.1 Spurling pipes and cable lockers are to be watertight up to the weather deck.
2.1.2Where means of access is provided, it is to be closed by a substantial cover and secured by closely spaced bolts.
2.1.3 Spurling pipes through which anchor cables are led are to be provided with permanently attached closing
appliances to minimize water ingress.
3. Adequate drainage facilities of the chain locker are to be provided.
4. Where the chain locker boundaries are also tank boundaries their scantlings of stiffeners and plating are to be
determined as for tanks in accordance with Section 12.
Where this is not the case the plate thickness is to be determined as for t2 and the section modulus as for W2 in accordance
with Section 12, B.2. and B.3. respectively. The distance from the load centre to the top of the chain locker pipe is to be
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-272-320.jpg)
![Section 18 - Equipment F 18-5/10
taken for calculating the load.
5. For th e location of chain lockers on tankers Section 24, A.9 is to be observed.
F. Mooring Equipment
1. Ropes
1.1 The following items 1.2 to 1.6 and the Tables 18.1 and 18.2 for tow lines and mooring ropes are recommendations
only, a compliance with which is not a condition of Class.
1.2 For tow lines and mooring lines, steel wire ropes as well as fibre ropes made of natural or synthetic fibres or wire
ropes consisting of steel wire and fibre cores may be used. The breaking loads 1)
specified in Table 18.2 are valid for wire
ropes and ropes of natural fibre (Manila) only. Where ropes of synthetic fibre are used, the breaking load is to be increased
above the table values. The extent of increase depends on the material quality.
The required diameters of synthetic fibre ropes used in lieu of steel wire ropes may be taken from Table 18.1.
Table 18.1 - Wire/ fibre ropes diameter
Steel wire
ropes 1)
Synthetic wire
ropes Poly-
amide2)
Fibre ropes
Polyamide Polyester Polypropylene
dia.
[mm]
dia.
[mm]
dia.
[mm]
dia.
[mm]
dia.
[mm]
12
13
14
16
18
20
22
24
26
28
32
36
40
30
30
32
32
36
40
44
48
56
60
68
72
72
30
32
36
40
44
48
48
52
60
64
72
80
88
30
32
36
40
44
48
48
52
60
64
72
80
88
30
32
36
40
44
48
52
56
64
72
80
88
96
1)
According to DIN 3068 or equivalent
2)
Regular laid ropes of refined polyamide monofilaments and filament fibres.
1.3 Where the stream anchor is used in conjunction with a rope, this is to be a steel wire rope.
1.4 Wire ropes shall be of the following type:
– 6 x 24 wires with 7 fibre cores for breaking loads of up to 500 kN
type: Standard
– 6 x 36 wires with 1 fibre core for breaking loads of more than 500 kN
type: Standard.
Where wire ropes are stored on mooring winch drums, steel cored wire ropes may be used e.g. :
– 6 x 19 wires with 1 steel core
1)
The term "Breaking Load" used throughout this Section means the "Nominal breaking load".
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-273-320.jpg)
![Section 18 - Equipment F 18-7/10
2) The minimum design load applied to supporting hull structures for winches, etc. is to be the design load acc. to (1).
For capstans, the minimum design load is to be 1,25 times the maximum hauling-in force.
3) The design load is to be applied through the mooring line according to the arrangement shown on the towing
and mooring arrangements plan, see Fig. 18.2.
4) When a specific SWLGL, that is greater than required in 2.2 (1), is applied for a fitting at the request of the applicant,
the fitting and the supporting hull structure have to be designed using the requested SWLGL times 1,875 as design load.
Fig. 18.2 Application of design loads
5) The acting point of the mooring force on shipboard fittings is to be taken at the attachment point of a mooring line or
at a change in its direction.
For bollards, the acting point of the design load is to be taken at least equivalent to the diameter of the pipe above deck
level. Special designs have to be evaluated individually.
3.2 Allowable stresses
Normal stress: FN < ReH
Shear stress: J 0,6 ReH
Equivalent stress: FV ReH
ReH = Nominal upper yield point of the material used [N/mm2
] acc. Section 2, B.2.
4. Corrosion addition
The total corrosion addition, tk, in mm, for both sides of the hull supporting structure is not to be less than the following
values:
– Ships covered by CSR for bulk carriers and CSR for double hull oil tankers: Total corrosion additions defined in these
rules
– Other ships: 2,0 mm in general and 1,0 mm in dry spaces
5. Equipment for mooring at single point moorings
5. 1 Upon request from the owner, BKI is prepared to certify that the vessel is specially fitted for compliance with
Sections 2.1, 4.2 and 6. of the "Standards for equipment employed in the mooring of ships at single point moorings"
published by the Oil Companies International Marine Forum (OCIMF), 1978.
5. 2 The certificate may be issued if
.1 plans showing the equipment and the arrangement as well as necessary substructures are submitted for approval;
.2 the chain stopper, Smith bracket, or other device for securing the chafing chain to the ship and the structure to which
it is attached are capable of withstanding a load not less than the breaking strength of the chain corresponding to the
size of the ship as given in Section 6 of the standards stipulated in 5.1 above and calculations to demonstrate this
capability are submitted;
.3 the chain bearing surface of the bow fairleads described in 6.1 of the standard stipulated in 3.5.1 above have a diameter
at least seven times that of the associated chain;
.4 the installation on board the ship is surveyed by BKI’s Surveyor.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-275-320.jpg)
![G Section 18 - Equipment18-8/10
G. Towing Equipment
1. Shipboard fittings
1.1 Arrangement and strength
Shipboard fittings for towing are to be located on longitudinals, beams and/or girders, which are part of the deck construction
so as to facilitate efficient distribution of the towing load. Other arrangements may be accepted (for Panama chocks, etc.)
provided the strength is confirmed adequate for the intended service.
The strength of shipboard fittings used for ordinary towing operations (not emergency towing) at bow, sides and stern and
their supporting hull structures are to be determined on the basis of 1.1.1 and 1.1.2.
Strength calculations are to be based on net thicknesses
tnet = t – tk
tk = corrosion addition, see F.4.
1.1.1 Load considerations
Unless greater safe working load (SWL) of shipboard fittings is specified by the applicant, the minimum design load to be
used is the following value of (1) or (2), whichever is applicable:
1) for normal towing operations (e.g., in harbour) using fittings at bow, sides and stern, 1,875 times the intended
maximum towing load (e.g. static bollard pull) as indicated on the towing and mooring arrangements plan.
If the intended maximum towing load is not specified by the applicant, the nominal breaking strength of the
corresponding mooring lines according to Table 18.2 for the equipment numeral Z2 is to be applied.
2) for other towing service using the forward main towing fittings, in general arranged on forecastle deck at the vessel's
centreline, the nominal breaking strength of the tow line according to Table 18.2 for the equipment numeral Z2.
3) The design load is to be applied through the tow line according to the arrangement shown on the towing and mooring
arrangements plan, see Fig. 18.2.
For bollards, the acting point of the design load is to be taken at least equivalent to the diameter of the pipe above deck
level. Special designs have to be evaluated individually.
4) When a specific SWLGL, that is greater than required in 1.2, is applied for a fitting at the request of the applicant, the
fitting and the supporting hull structure have to be designed using the requested SWLGL times 1,875 as design load.
1.1.2 Allowable stresses
Normal stress: FN < ReH
Shear stress: J < 0,6 ReH
Equivalent stress: FV < ReH
ReH = Nominal upper yield point of the material used [N/mm2
] acc. Section 2, B.2.
1.2 Safe working load (SWL)
1) The safe working load for a shipboard fitting used for normal towing operations is not to exceed the following value:
FD = design load per 1.1.1(1)
2) The safe working load for a shipboard fitting used for other towing service (i.e., for the main towing fittings) is not
to exceed the following value:
FD = design load per 1.1.1(2).
3) For chocks and bollards of which the strength shall comply with Panama Canal Regulations, the safe working load is
not to exceed the following value:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-276-320.jpg)
![H Section 18 - Equipment18-10/10
Table 18.2 - Anchor, Chain Cables and Ropes
No. for
Reg.
Equipment
numeral
Z1 or Z2
Stockless anchor Stud link chain cables Recommended ropes
Bower anchor
Stream
anchor
Bower anchors
Stream wire or
chain for stream
anchor
Towline Mooring ropes
Num-
ber 1)
Mass
per anchor
Total
length
Diameter
Length
Br.
load2) Length
Br.
load2)
Num-
ber
Length
Br.
load2)
d1 d2 d3
[kg] [m] [mm] [mm] [mm] [m] [kN] [m] [kN] [m] [kN]
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
up to 50
50 - 70
70 - 90
90 - 110
110 - 130
130 - 150
150 - 175
175 - 205
205 - 240
240 - 280
280 - 320
320 - 360
360 - 400
400 - 450
450 - 500
500 - 550
550 - 600
600 - 660
660 - 720
720 - 780
780 - 840
840 - 910
910 - 980
980 - 1060
1060 - 1140
1140 - 1220
1220 - 1300
1300 - 1390
1390 - 1480
1480 - 1570
1570 - 1670
1670 - 1790
1790 - 1930
1930 - 2080
2080 - 2230
2230 - 2380
2380 - 2530
2530 - 2700
2700 - 2870
2870 - 3040
3040 - 3210
3210 - 3400
3400 - 3600
3600 - 3800
3800 - 4000
4000 - 4200
4200 - 4400
4400 - 4600
4600 - 4800
4800 - 5000
5000 - 5200
5200 - 5500
5500 - 5800
5800 - 6100
6100 - 6500
6500 - 6900
6900 - 7400
7400 - 7900
7900 - 8400
8400 - 8900
8900 - 9400
9400 - 10000
10000 - 10700
10700 - 11500
11500 - 12400
12400 - 13400
13400 - 14600
14600 - 16000
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
120
180
240
300
360
420
480
570
660
780
900
1020
1140
1290
1440
1590
1740
1920
2100
2280
2460
2640
2850
3060
3300
3540
3780
4050
4320
4590
4890
5250
5610
6000
6450
6900
7350
7800
8300
8700
9300
9900
10500
11100
11700
12300
12900
13500
14100
14700
15400
16100
16900
17800
18800
20000
21500
23000
24500
26000
27500
29000
31000
33000
35500
38500
42000
46000
40
60
80
100
120
140
165
190
165
220
220
247,5
247,5
275
275
302,5
302,5
330
357,5
357,5
385
385
412,5
412,5
440
440
440
467,5
467,5
467,5
495
495
495
522,5
522,5
522,5
550
550
550
577,5
577,5
577,5
605
605
605
632,5
632,5
632,5
660
660
660
687,5
687,5
687,5
715
715
715
742,5
742,5
742,5
742,5
742,5
742,5
770
770
770
770
770
770
770
770
770
770
770
770
770
12,5
14
16
17,5
19
20,5
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
62
64
66
68
70
73
76
78
81
84
87
90
92
95
97
100
102
105
107
111
114
117
120
122
124
127
130
132
12,5
12,5
14
16
17,5
17,5
19
20,5
22
24
26
28
30
32
34
34
36
38
40
42
44
46
48
50
50
52
54
56
58
60
62
64
66
68
70
73
76
78
81
84
84
87
90
92
95
97
100
102
105
107
111
111
114
117
120
124
127
132
137
142
147
152
12,5
12,5
14
16
17,5
17,5
19
20,5
20,5
22
24
24
26
28
30
30
32
34
36
36
38
40
42
44
46
46
48
50
50
52
54
56
58
60
62
64
66
68
70
73
76
78
78
81
84
87
87
90
92
95
97
97
100
102
107
111
114
117
122
127
132
132
137
142
147
152
157
162
80
80
85
85
90
90
90
90
65
65
75
80
90
100
110
120
180
180
180
180
180
180
180
180
180
180
180
180
180
180
180
190
190
190
190
190
190
190
190
200
200
200
200
200
200
220
220
220
220
220
240
240
240
260
260
260
280
280
280
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
100
100
100
100
100
100
100
110
130
150
175
200
225
250
275
305
340
370
405
440
480
520
560
600
645
690
740
785
835
890
940
1025
1110
1170
1260
1355
1455
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
1470
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
6
6
6
6
6
6
6
6
7
7
7
7
7
8
8
8
9
9
9
10
11
11
12
13
14
15
16
17
18
19
21
80
80
100
110
110
120
120
120
120
120
140
140
140
140
140
160
160
160
160
170
170
170
170
180
180
180
180
180
180
190
190
190
190
190
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
35
35
40
40
45
50
55
60
65
70
80
85
95
100
110
120
130
145
160
170
185
200
215
230
250
270
285
305
325
325
335
350
375
400
425
450
480
480
490
500
520
555
590
620
650
650
660
670
680
685
685
695
705
705
715
725
725
725
735
735
735
735
735
735
735
735
735
735
d1 = Chain diameter Grade K 1 (Ordinary quality)
d2 = Chain diameter Grade K 2 (Special quality)
d3 = Chain diameter Grade K 3 (Extra special quality)
See also D
1)
see C.1.
2)
see F.1.2
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-278-320.jpg)
![Section 19 - Welded Joints B 19-3/20
2.1.6Where the plate thickness differs at joints perpendicularly to the direction of the main stress, differences in thickness
greater than 3 mm shall be accommodated by bevelling the proud edge in the manner shown in Fig. 19.1 at a ratio of at least
1 : 3 or according to the notch category. Differences in thickness of 3 mm or less may be accommodated within the weld.
2.1.7For the welding on of plates orotherrelatively thin-walled elements, steel castings and forgings should be appropriately
tapered or provided with integrally cast or forged welding flanges in accordance with Fig. 19.2.
Fig. 19.1 Accommodation of differences of thickness Fig. 19.2 Welding flanges on steel castings or forgings
2.1.8For the connection of shaft brackets to the boss and shell plating, see 4.3 and Section 13, D.2.; for the connection of
horizontal coupling flanges to the rudder body, see 4.4 For the required thickened rudderstock collar required with build-up
welds and for the connection of the coupling flange, see 2.7 and Section 14, D.2.4. The joint between the rudder-stock and
the coupling flange are to be connected by full penetration weld.
2.2 Local clustering of welds, minimum spacing
2.2.1 The local clustering of welds and short distances between welds are to be avoided. Adjacent butt welds should
be separated from each other by a distance of at least:
50 mm + 4 × plate thickness.
Fillet welds should be separated from each other and from butt welds by a distance of at least:
30 mm + 2 × plate thickness.
Thewidthofreplacedorinsertedplates(strips)should,however,beatleast300mmortentimestheplatethickness,whichever
is the greater.
2.2.2Reinforcing plates, welding flanges, mountings and similar components socket-welded into plating should be of the
following minimum size:
Dmin =
D = diameter of round or length of side of angular weldments [mm]
t = plating thickness [mm].
The corner radii of angular socket weldments should be 5t [mm] but at least 50 mm. Alternatively the ”longitudinal seams”
are to extend beyond the ”transverse seams”. Socket weldments are to be fully welded to the surrounding plating. Regarding
the increase of stress due to different thickness of plates see also Section 20, B.1.3.
2.3 Welding cut-outs
2.3.1 Welding cut-outs for the (later) execution of butt or fillet welds following the positioning of transverse members
should be rounded (minimum radius 25 mm or twice the plate thickness, whichever is the greater) and should be shaped to
provide a smooth transition on the adjoining surface as shown in Fig. 19.3 (especially necessary where the loading is mainly
dynamic).
2.3.2 Where the welds are completed prior to the positioning of the crossing members, no welding cut-outs are needed.
Any weld reinforcements present are to be machined off prior to the location of the crossing members or these members
are to have suitable cut-outs.
2.4 Local reinforcements, doubling plates
2.4.1Where plating (including girder plates and tube walls) are subjected locally to increased stresses, thicker plates should
be used wherever possible in preference todoubling plates. Bearing bushes, hubs etc. shall invariably take the formof thicker
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-281-320.jpg)
![B Section 19 - Welded Joints19-4/20
sections welded into the plating, see 2.2.2.
2.4.2Where doublings cannot be avoided, the thickness of the doubling plates should not exceed twice the plating thickness.
Doubling plates whose width is greater than approximately 30 times their thickness shall be slot welded to the underlying
plating in accordance with 3.3.11 at intervals not exceeding 30 times the thickness of the doubling plate.
2.4.3Along their (longitudinal) edges, doubling plates shall be continuously fillet welded with a throat thickness "a" of 0,3
x the doubling plate thickness. At the ends of doubling plates, the throat thickness "a" at the end faces shall be increased
to 0,5 x the doubling plate thickness but shall not exceed the plating thickness, see Fig. 19.4.
The welded transition at the end faces of the doubling plates to the plating should form with the latter an angle of 45E or
less.
Fig. 19.3 Welding cut-outs Fig. 19.4 Welding at the ends of doubling plates
2.4.4Where proof of fatigue strength is required (see Section 20), the configuration of the end of the doubling plate shall
conform to the selected detail category.
2.4.5Doubling plates are not permitted in tanks for flammable liquids.
2.5 Intersecting members, stress in the thickness direction
2.5.1Where, in the case of intersecting members, plates or other rolled products are stressed in the thickness direction by
shrinking stresses due to the welding and/or applied loads, suitable measures shall be taken in the design and fabrication
of the structures to prevent lamellar tearing (stratified fractures) due to the anisotropy of the rolled products.
2.5.2Such measures include the use of suitable weld shapes with a minimum weld volume and a welding sequence designed
to reduce transverse shrinkage. Other measures are the distribution of the stresses over a larger area of the plate surface by
using a build-up weld or the joining together of several "fibres" of members stressed in the thickness direction as exemplified
by the deck stringer/sheer strake joint shown in Fig. 19.12.
2.5.3 In case of very severe stresses in the thickness direction due, for example, to the aggregate effect of the shrinkage
stressesofbulkysingleordouble-bevelbuttweldsplushighappliedloads,plateswithguaranteedthroughthicknessproperties
(extrahigh-puritymaterialandguaranteedminimumreductions inarea oftensile testspecimenstakeninthicknessdirection)1)
are to be used.
2.6 Welding of cold formed sections, bending radii
2.6.1 Whereverpossible,weldingshouldbeavoidedatthecoldformedsectionswithmorethan5%permanent elongation2)
and in the adjacent areas of structural steels with a tendency towards strain ageing.
1)
See Rules for Materials, Vol. V, Section 4, I.
2)
Elongation g in the outer tensile-stressed zone
, =
r = inner bending radius [mm]
t = plate thickness [mm]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-282-320.jpg)
![Section 19 - Welded Joints B 19-9/20
amin = [mm] but not less than 3 mm
t1 = lesser (e.g. the web) plate thickness [mm]
t2 = greater (e.g. the flange) plate thickness [mm].
3.3.4It is desirable that the fillet weld section shall be flat faced with smooth transitions to the base material. Where proof
offatiguestrengthisrequired(seeSection20),machiningoftheweld(grindingtoremovenotches)mayberequireddepending
on the notch category. The weld should penetrate at least close to the theoretical root point.
3.3.5Where mechanical welding processes are used which ensure deeper penetration extending well beyond the theoretical
root point and where such penetration is uniformly and dependably maintained under production conditions, approval may
be given for this deeper penetration to be allowed for in determining the throat thickness. The effective dimension:
[mm]
shall be ascertained in accordance with Fig. 19.14 and by applying the term "emin" to be established for each welding process
by a welding procedure test. The throat thickness shall not be less than the minimumthroat thickness related to the theoretical
root point.
Fig. 19.14 Fillet welds with increased penetration
3.3.6When welding on top of shop primers which are particularly liable to cause porosity, an increase of the "a" dimension
by up to 1 mm may be stipulated depending on the welding process used. This is specially applicable where minimum fillet
weld throat thicknesses are employed. The size of the increaseshall be decided on a case by case basis considering the nature
and severity of the stressing following the test results of the shop primer in accordance with the Rules for Welding, Volume
VI, Section 12, F. This applies in analogous manner to welding processes where provision has to be made for inadequate
root penetration.
3.3.7Strengthened fillet welds continuous on both sides are to be used in areas subjected to severe dynamic loads (e.g. for
connecting the longitudinal and transverse girders of the engine base to top plates close to foundation bolts, see Section 8,
C.3.2.5 and Table 19.3), unless single or double bevel welds are stipulated in these locations. In these areas the "a" dimension
shall equal 0,7 times the lesser thickness of the parts to be welded.
3.3.8Intermittent fillet welds in accordance with Table 19.3 may be located opposite one another (chain intermittent
welds, possibly with scallops) or may be staggered, see Fig. 19.15. In case of small sections other types of scallops may be
accepted.
In water and cargo tanks, inthebottomarea of fuel oil tanksand of spaces where condensed or sprayed water may accumulate
and in hollow components (e.g. rudders) threatened by corrosion, only continuous or intermittent fillet welds with scallops
shall be used. This applies accordingly also to areas, structures or spaces exposed to extreme environmental conditions or
which are exposed to corrosive cargo.
There shall be no scallops in areas where the plating is subjected to severe local stresses (e.g. in the bottom section of the
fore ship) and continuous welds are to be preferred where the loading is mainly dynamic.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-287-320.jpg)
![B Section 19 - Welded Joints19-10/20
Fig. 19.15 Scallop, chain and staggered welds
3.3.9 The throat thickness au of intermittent fillet welds is to be determined according to the selected pitch ratio b/R
by applying the formula:
au = [mm]
a = required fillet weld throat thickness [mm] for a continuous weld according to Table 19.3 or determined by
calculation
b = pitch = e + R [mm]
e = interval between the welds [mm]
R = length of fillet weld [mm]
The pitch ratio b/R should not exceed 5. The maximum unwelded length (b - R with scallop and chain welds, or b/2 - R with
staggered welds) should not exceed 25 times the lesser thickness of the parts to be welded. The length of scallops should,
however, not exceed 150 mm.
3.3.10 Lap joints should be avoided wherever possible and are not to be used for heavily loaded components. In the case
of components subject to low loads lap joints may be accepted provided that, wherever possible, they are orientated parallel
to the direction of the main stress. The width of the lap shall be 1,5 t + 15 mm (t = thickness of the thinner plate). Except
where another value is determined by calculation, the fillet weld throat thickness "a" shall equal 0,4 times the lesser plate
thickness, subject to the requirement that it shall not be less than the minimum throat thickness required by 3.3.3. The fillet
weld shall be continuous on both sides and shall meet at the ends.
3.3.11 Inthecaseofslotwelding,theslotsshould,whereverpossible,taketheformofelongatedholeslyinginthedirection
of the main stress. The distance between the holes and the length of the holes may be determined by analogy with the pitch
"b"andthefilletweldlength"R"intheintermittentweldscoveredby3.3.8.Thefilletweldthroatthickness"au"maybeestablished
in accordance with 3.3.9. The width of the holes shall be equal to at least twice the thickness of the plate and shall not be
less than 15 mm. The ends of the holes shall be semi-circular. Plates or sections placed underneath should at least equal
theperforatedplateinthicknessandshouldprojectonbothsidestoadistance of1,5x the plate thickness subjecttoamaximum
of 20 mm. Wherever possible only the necessary fillet welds shall be welded, while the remaining void is packed with a
suitable filler. In special cases, instead of slot welding, plug weld may be approved by BKI. Lug joint welding is not allowed.
4. Welded joints of particular components
4.1 Welds at the ends of girders and stiffeners
4.1.1As shown in Fig. 19.16, the web at the end of intermittently welded girders or stiffeners is to be continuously welded
to the plating or the flange plate, as applicable, over a distance at least equal to the depth "h" of the girder or stiffener subject
to a maximum of 300 mm. Regarding the strengthening of the welds at the ends, extending normally over 0,15 of the span,
see Table 19.3.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-288-320.jpg)
![B Section 19 - Welded Joints19-12/20
Fig. 19.18 - Shaft bracket with integrally cast welding flanges
t = plating thickness in accordance with Section 6, F. [mm]
t' = [mm]where d < 50mm
= [mm]where d 50mm
For shaft brackets of elliptically shaped cross section d may be substituted by 2/3 d
in the above formulae.
Fig. 19.19 - Shaft bracket without integrally cast welding flanges
4.4 Rudder coupling flanges
4.4.1Unless forged or cast steel flanges with integrally forged or cast welding flanges in conformity with 2.1.7 are used,
horizontal rudder coupling flanges are to be joined to the rudder body by plates of graduated thickness and full penetration
single or double-bevel welds as prescribed in 3.2.1, see Fig. 19.20. See also Section 14, D.1.4 and D.2.4.
4.4.2Allowance shall be made for the reduced strength of the coupling flange in the thickness direction, see 1.5 and 2.5. In
case of doubt, proof by calculation of the adequacy of the welded connection shall be produced.
4.4.3The welded joint between the rudder stock (with thickened collar, see 2.1.8) and the flange shall be made in accordance
with Fig. 19.21a.
For small stock diameter welded joint in accordance with Fig. 19.21b may be applied.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-290-320.jpg)
![Section 19 - Welded Joints B 19-13/20
t = plate thickness in accordance with Section 14, E.3.1 [mm]
tf = actual flange thickness [mm]
t' = [mm] where tf < 50 mm
= [mm] where tf 50 mm
Fig. 19.20 - Horizontal rudder coupling flanges
Fig. 19.21a - Welded joint between rudder stock and coupling flange
Fig. 19.21b - Welded joint between rudder stock and coupling flange for small stock diameter
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-291-320.jpg)
![C Section 19 - Welded Joints19-14/20
C. Stress Analysis
1. General analysis of fillet weld stresses
1.1 Definition of stresses
For calculation purposes, the following stresses in a fillet weld are defined (see also Fig. 19.22):
Fz = normal stresses acting vertically to the direction of the weld seam
Jz = shear stress acting vertically to the direction of the weld seam
J## = shear stress acting in the direction of the weld seam.
Fig. 19. 22 Stresses in a fillet weld
Normal stresses acting in the direction of the weld seam need not be considered.
For calculation purposes the weld seam area is a @ R
Due to equilibrium condition the following applies to the flank area vertical to the shaded weld seam area
Jz = Fz
The equivalent stress is to be calculated by the following formula:
Fv =
1.2 Definitions
a = throat thickness [mm]
R = length of fillet weld [mm]
P = single force [N]
M = bending moment at the position considered [Nm]
Q = shear force at the point considered [N]
S = first moment of the cross sectional area of the flange connected by the weld to the web in relationship to
the neutral beam axis [cm3
]
I = moment of inertia of the girder section [cm4
]
W = section modulus of the connected section [cm3
].
2. Determination of stresses
2.1 Fillet welds stressed by normal and shear forces
Flank and frontal welds are regarded as being equal for the purposes of stress analysis. In view of this, normal and shear
stresses are calculated as follows:
F = J = [N/mm2
]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-292-320.jpg)
![Section 19 - Welded Joints C 19-15/20
Joint as shown in Fig. 19.23:
Fig. 19.23 Weld joint of an overlapped lifting eye
- Stresses in frontal fillet welds:
Jz = [N/mm2
]
J## = [N/mm2
]
Ft = [mm2
]
- Stresses in flank fillet welds :
Jz = [N/mm2
]
J## = [N/mm2
]
R1, R2, e [mm]
- Equivalent stress for frontal and flank fillet welds:
Fv = [N/mm2
]
Joint as shown in Fig. 19.24:
Fig. 19.24 Weld joint of a vertically mounted lifting eye
Jz = [N/mm2
]
J## = [N/mm2
]
– Equivalent stress :
Fv = [N/mm2
]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-293-320.jpg)
![C Section 19 - Welded Joints19-16/20
2.2 Fillet weld joints stressed by bending moments and shear forces
The stresses at the fixing point of a girder are calculated as follows (in Fig. 19.25 a cantilever beam is given as an example):
Fig. 19.25 Fixing point of cantilever beam
.1 Normal stress due to bending moment:
Fz(z) = [N/mm2
]
Fzmax = [N/mm2
], if eu > e0
= [N/mm2
], if eu < e0
.2 Shear stress due to shear force:
J## (z) = [N/mm2
]
J## max = [N/mm2
]
Is = moment of inertia of the welded joint related to the x-axis [cm4
]
Ss (z)= the first moment of the connected weld section at the point under consideration [cm3
]
z = distance from the neutral axis [cm].
.3 Equivalent stress :
IthastobeprovedthatneitherFzmax intheregionoftheflangenor max intheregionoftheneutralaxisnortheequivalent
stress Fv= exceed the permitted limits given in 2.8 at any given point. The equivalent stress Fvshould always
be calculated at the web-flange connection.
2.3 Fillet welded joints stressed by bending and torsional moments and shear forces
Regardingthenormalandshearstressesresultingfrombending,see2.2.Torsionalstressesresultingfromthetorsionalmoment
MT are to be calculated:
JT = [N/mm2
]
MT = torsional moment [Nm]
Am = sectional area [mm2
] enclosed by the weld seam.
The equivalent stress composed of all three components (bending, shear and torsion) is calculated by means of the following
formulae:
Fv = [N/mm2
]
where and JT have not the same direction
Fv = [N/mm2
]
where and JT have the same direction.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-294-320.jpg)
![Section 19 - Welded Joints C 19-17/20
2.4 Continuous fillet welded joints between web and flange of bending girders
The stresses are to be calculated in way of maximum shear forces. Stresses in the weld’s longitudinal direction need not to
be considered. In the case of continuous double fillet weld connections the shear stress is to be calculated as follows:
J## = [N/mm2
]
The fillet weld thickness required is:
areq = [mm]
2.5 Intermittent fillet weld joints between web and flange of bending girders
Shear stress :
J## = [N/mm2
]
b = pitch
" = 1,1 stress concentration factor which takes into account increases in shear stress at the ends of the fillet
weld seam "R ".
Fig. 19.26 Intermittent fillet weld joint
The fillet weld thickness required is :
areq = [mm]
2.6 Fillet weld connections on overlapped profile joints
2.6.1Profiles joined by means of two flank fillet welds (see Fig. 19.27):
Jz = [N/mm2
]
J## = [N/mm2
]
Fig. 19.27 Profile joined by means of two flank fillet joints
The equivalent stress is :
Fv = [N/mm2
]
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-295-320.jpg)
![C Section 19 - Welded Joints19-18/20
c, d, R1, R2, r [mm] see Fig. 19.27
c = [mm]
As the influence of the shear force can generally be neglected, the required fillet weld thickness may be determined by the
following formula :
areq = [mm]
2.6.2 Profiles joined by means of two flank and two frontal fillet welds (all round welding as shown in Fig. 19.28):
Jz = [N/mm2
]
J## = [N/mm2
]
The equivalent stress is :
Fv = [N/mm2
]
areq = [mm]
Fig. 19.28 Profile joined by means of two flank and two frontal fillet welds (all round welding)
2.7 Bracket joints
Where profiles are joined to brackets as shown in Fig. 19.29, the average shear stress is :
J = [N/mm2
]
d = length of overlap [mm]
Fig. 19.29 Bracket joint with idealized stress distribution resulting from moment M and shear force Q
The required fillet weld thickness is to be calculated from the section modulus of the profile as follows :
areq = [mm].
(The shear force Q has been neglected.)
2.8 Permissible stresses
The permissible stresses for various materials under mainly static loading conditions are given in Table 19.2. The values
listed for high strength steels, austenitic stainless steels and aluminium alloys are based on the assumption that the strength
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-296-320.jpg)
![Section 19 - Welded Joints C 19-19/20
values of the weld metal used are at least as high as those of the parent metal. If this is not the case, the "a" value calculated
shall be increased accordingly (see also B.3.3.2).
Table 19.2 - Permissible stresses in fillet weld seams
Material
ReH or Rp0,2
[N/mm2
]
Permissible stresses [N/mm2
]
equivalent stress, shear stress
Fvp, Jp
normal strength hull structural steel KI - A/B/D/E 235 115
higher strength
hull structural steel
KI - A/D/E/F 32 315 145
KI - A/D/E/F 36 355 160
KI - A/D/E/F 40 390 175
high strength steels
S 460 460 200
S 690 685 290
austenitic and austenitic-
ferritic stainless steels
1.4306/304 L 180
110
1.4404/316 L 190
1.4435/316 L 190
1.4438/317 L 195
1.4541/321 205
1.4571/316 Ti 215
1.4406/316 LN 280
1301.4429/316 LN 295
1.4439/317 LN 285
1.4462/318 LN 480 205
aluminium alloys
Al Mg 3/5754 80 1)
35
AlMg4,5Mn0,7/5083 125 1)
56
Al Mg Si/6060 652)
30
Al Mg Si Mn/6082 110 2)
45
1)
Plates, soft condition
2)
Sections, cold hardened
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-297-320.jpg)
![Section 20 - Fatigue Strength A 20-1/20
Section 20
Fatigue Strength
Preamble
The proof of sufficient fatigue strength, i.e. the strength against crack initiation under dynamic loads during operation, is
useful for judging and reducing the probability of crack initiation of structural members during the design stage.
Due to the randomness of the load process, the spreading of material properties and fabrication factors and to effects of
ageing, crack initiation cannot be completely excluded during later operation. Therefore among other things periodical
surveys are necessary.
A. General
1. Definitions
Fig. 20.1 Dynamic Load cycle
)F = applied stress range (Fmax S Fmin) [N/mm2
], see also Fig. 20.1
Fmax = maximum upper stress of a stress cycle [N/mm2
]
Fmin = maximum lower stress of a stress cycle [N/mm2
]
Fm = mean stress (Fmax/2 + Fmin/2) [N/mm2
]
)Fmax = applied peak stress range within a stress range spectrum [N/mm2
]
)Fp = permissible stress range [N/mm2
]
)J = corresponding range for shear stress [N/mm2
]
n = number of applied stress cycles
N = number of endured stress cycles according to S-N curve (= endured stress cycles under constant
amplitude loading)
)FR = fatigue strength reference value of S-N curve at 2 @ 106
cycles of stress range [N/mm2
] (= detail
category number according to Table 20.3)
fm = correction factor for material effect
fR = correction factor for mean stress effect
fw = correction factor for weld shape effect
fi = correction factor for importance of structural element
fs = additional correction factor for structural stress analysis
fn = factor considering stress spectrum and number of cycles for calculation of permissible stress range.
)FRc = corrected fatigue strength reference value of S-N curve at 2 @ 106
stress cycles [N/mm2
]
D = cumulative damage ratio.
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![A Section 20 - Fatigue Strength20-4/20
Table 20.1 Maximum and minimum value for seaway-induced cyclic loads
Load Maximum load Minimum load
Vertical longitudinal bending
moments (Section 5, B.)1)
MSW + MST + fQ.MWVhog MSW + MST + fQ.MWVsag
Vertical bending moments
and horizontal wave bending
moments 1)
(Section 5, B.)
MSW + MST
+ fQ.(0,6.MWVhog + MWH)
MSW + MST
+ fQ.(0,6.MWVhog - MWH)
Vertical longitudinal bending
moments , horizontal wave bending
moments and torsional moments1)
(Section 5, B.)
fF.{MSW + MST
+ fQ.[(0,43+C).MWVhog
+ MWH + MWT]}
fF.{MSW + MST
+ fQ.[(0,43+C.(0,5-C)).MWVhog
+ C.(0,43+C).MWVsag - MWH - MWT]}
C =
Loads on weather decks 2)
Section 4, B.1.)
pD 0
Loads on ship’s sides 2), 4)
– below T
– above T
(Section 4, B.2.)
10 (T S z) + p0 @ cF
p0 @ cF
10 (T S z) S p0 @ cF
but $ 0
0
Loads on ship’s bottom 2), 4)
(Section 4, B.3.)
10 T + p0 @ cF 10 T S p0 @ cF
Liquid pressure in completely filled
tanks 4)
(Section 4, D.1.)
9,81@ h1 @ D (1 + av) + 100 pv
or
9,81 @ D ”h1@ cos n
+ (0,3@ b + y)sin n ] + 100 pv
9,81@ h1 @ D (1 S av) + 100 pv
or
9,81 @ D ”h1@ cos n + (0,3@ b S y)sin n ]
+ 100 pv but 100 pv
Loads due to cargo 5)
(Section 4, C.1.1 and E.1)
p (1 + av)
p @ ax @ 0,7
p @ ay @ 0,7
p (1 S av )
S p @ ax @ 0,7
S p @ ay @ 0,7
Loads due to friction forces 3)
(Section 17, B.4.5.5)
Ph S Ph
Loads due to rudder forces 3)
(Section 14, B.)
CR
QR
– CR
– QR
1)
Maximum and minimum load are to be so determined that the largest applied stress range )F as per Figure 20.1 at conservative
mean stress is obtained having due regard to the sign (plus, minus). For fF, fQ see Section 5.D.1
2)
With probability factor f for calculation p0 according to Section 4, A.2.2.: however
f = 1,0 for stiffeners if no other cyclic load components are considered
3)
In general the largest friction load is to be taken in connection with the load spectrum B without considering further cyclic loads.
4)
Assumption of conservative super positioning for the shell: Where appropriate, proof is to be furnished for Tmin.
5)
Probability factor fQ = 1,0 used for determination of a0 and further calculation of ax and ay according to Section 4, E.1.
3. Quality requirements (fabrication tolerances)
3.1 The detail classification of the different welded joints as given in Table 20.3 is based on the assumption that the
fabrication of the structural detail or welded joint, respectively, corresponds in regard to external defects at least to quality
group B according to DIN EN ISO 5817 and in regard t internal defects at least to quality group C. Further information about
the tolerances can also be found in the Rules for Welding, Volume VI, Appendix 6.
3.2 Relevant information have to be included in the manufacturing document for fabrication. If it is not possible to
comply with the tolerances given in the standards this has to be accounted for when designing the structural details or welded
joints, respectively. In special cases an improved manufacture as stated in 3.1 may be required, e.g. stricter tolerances or
improved weld shapes, .see also B.3.2.4.
3.3 The following stress increase factors km for considering significant influence of axial and angular misalignment
are already included in the fatigue strength reference values )FR (Table 20.3) :
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-302-320.jpg)
![Section 20 - Fatigue Strength B 20-7/20
Table 20.2 - Factor fn for the determination of the permissible range for standard stress range spectra
Stress
range Welded Joints Plates Edges
(m0 = 3)
n max =
type E1 (m0 = 5)
n max =
type E2 (m0 = 4)
n max =
type E3 (m0 = 3,5)
n max =
103
105
5 × 107
108
103
105
5 × 107
108
103
105
5 × 107
108
103
10 5
5 × 107
108
A (17,2) 3,53 3,02 (8,1) 3,63 3,32 (9,2) 3,68 3,36
10,3
12,22) 3,65 3,19
B (9,2) 1,67 1,43 (9,5) 5,0 1,95 1,78 (11,2) 5,9 1,86 1,65
6,6
7,52) 1,78 1,55
C (12,6) 2,71
0,424
0,5431)
0,369
0,5261) 4,57 1,82
0,606
0,6731)
0,561
0,6531) (5,2) 2,11
0,532
0,6211)
0,482
0,6021) (8,8) 2,35
0,483
0,5871)
0,430
0,5691)
For definition of type E1 to type E3 see Table 20.3
For definition of m0 see 3.1.2
The values given in parentheses may be applied for interpolation.
For interpolation between any pair of values (nmax1 ; fn1 ) and (nmax2 ; fn2 ), the following formula may be applied in the case of
stress spectrum A or B:
For the stress spectrum C intermediate values may be calculated according to 3.1.2 by taking N = n max and f n = )F/)FR.
1)
fn for non-corrosive environment, see also 3.1.4.
2)
for )FR = 100 [N/mm2
]
3.1.4For stress ranges of constant magnitude (stress range spectrum C) in non-corrosive environment from N = 1 @ 107
the
S-N curves of type "O" in Fig. 20.3 and 20.4 can be used, thus:
m = m0 for N 107
(Q < 0)
= 22 for N > 107
(Q > 0)
3.2 Correction of the reference value of the design S-N curve
3.2.1A correction of the reference value of the S-N curve (or detail category) is required to account for additional influence
factors on fatigue strength as follows:
)FRc = fm @ fR @ fw @ fi @ ft @)FR
fm, fR, fw, fi, ft defined in 3.2.2 - 3.2.6
For the description of the corrected design S-N curve, the formulae given in 3.1.2 may be used by replacing )FR by )FRc.
3.2.2Material effect (fm)
For welded joints it is generally assumed that the fatigue strength is independent of steel strength, i.e. :
fm = 1,0.
For free edges at steel plates the effect of the material's yield point is accounted for as follows :
fm = 1 +
ReH = minimum nominal upper yield point of the steel [N/mm2
].
For aluminium alloys, f m = 1 generally applies.
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![Section 20 - Fatigue Strength B 20-9/20
Fm
fR = 1 + 2 @ c
c = 0 for welded joints subjected to constant stress cycles (stress range spectrum C)
= 0,15 for welded joints subjected to variable stress cycles (corresponding to stress range spectrum A or
B)
= 0,3 for unwelded base material.
3.2.4Effect of weld shape (fw)
In normal cases:
fw = 1,0.
A factor f w > 1,0 applies for welds treated e.g. by grinding. By this surface defects such as slag inclusions, porosity and
crack-like undercuts shall be removed and a smooth transition from the weld to the base material shall be achieved. Final
grinding shall be performed transversely to the weld direction. The depth should be approx. 0,5 mm larger than that of
visible undercuts.
For ground weld toes of fillet and K- butt welds machined by:
! disk grinder fw = 1,15.
! burr grinder fw = 1,30
For butt welds ground flush the corresponding detail category has to be chosen, e.g. type A1, A10 or A12 in Table 20.3.
For endings of stiffeners or brackets, e.g. type C4 or C6 in Table 20.3, which have a full penetration weld and are completely
ground flush to achieve a notch-free transition, the following factor applies:
fw = 1,4
The assessment of a local post-weld treatment of the weld surface and the weld toe by other methods e.g. ultrasonic impact
treatment has to be agreed on in each case.
3.2.5Influence of importance of structural element (fi)
In general the following applies:
fi = 1,0.
For secondary structural elements failure of which may cause failure of larger structural areas, the correction factor fi is to
be taken as:
fi = 0,9.
For notches at plate edges in general the following correction factor is to be taken which takes into account the radius of
rounding:
fi = 0,9 + 5/r 1,0.
r = notch radius [mm]; for elliptical roundings the mean value of the two main half axes may be taken.
3.2.6 Plate thickness effect (ft)
In order to account for the plate thickness effect, application of the reduction factor ft is required by BKI for butt welds
oriented transversely to the direction of applied stress for plate thicknesses t > 25 mm.
ft =
n = 0,17 as welded
n = 0,10 toe-ground
For all other weld connections consideration of the thickness effect may be required subject to agreement with BKI.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-307-320.jpg)
![Section 20 - Fatigue Strength C 20-19/20
Table 20.5 Examples of details
Detail
category
)FR
Steel
71
80
63
71
36
71
Descriptionofjoint
Cruciformortee-jointK-buttwelds
withfullpenetrationorwithdefined
incompleterootpenetrationaccording
toSection19,Fig.19.9.
cruciformjoint
tee-joint
Cruciformortee-jointwithtransverse
filletweld,toefailure(rootfailure
particularlyforthroatthicknessa<
0,7t,seejointtypeD3)
cruciformjoint
tee-joint
Weldedmetalintransverse
load-carryingfilletweldatcruciform
ortee-joint,rootfailure(basedon
stressrangeinweldthroat).Seealso
jointtypeNo.D2
R#150mm
Inwayoftheroundedcornerofan
openingwiththeradiusraminimum
distancexfromtheedgetobekept
(hatchedarea):
x[mm]=15+0,175Ar[mm]
100mm#r#400mm
Incaseofanellipticalroundingthe
meanvalueofbothsemiaxestobe
applied
Jointconfigurationshowing
modeoffatiguecrackingand
stressFconsidered
Type
No.
D1
D2
D3
C1
Descriptionofstructureor
equipmentdetail
Unstiffenedflangetowebjoint,tobe
assessedaccordingtotypeD1,D2orD3,
dependingonthetypeofjoint.
Thestressinthewebiscalculatedusingthe
forceFgintheflangeasfollows:
Furthermore,thestressinlongitudinalweld
directionhastobeassessedaccordingtotype
B2–B4.Incaseofadditionalshearor
bending,alsothehighestprincipalstressmay
becomerelevantintheweb,seeB.1.4.
Jointatstiffenedknuckleofaflange,tobe
assessedaccordingtotypeD1,D2orD3,
dependingonthetypeofjoint.
Thestressinthestiffenerattheknucklecan
normallybecalculatedasfollows:
F=Fa2sin"
Holderweldedinwayofanopeningandarranged
paralleltotheedgeoftheopening.
Notvalidforhatchcorner.
Structureor
equipmentdetail
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-317-320.jpg)
![Section 21 - Hull Outfit A, B 21-1/21
Section 21
Hull Outfit
A. Partition Bulkheads
1. General
Spaces,whicharetobeaccessiblefortheserviceoftheship,holdspacesandaccommodationspaces are to be gastight against
each other.
2. Partition bulkheads between engine and boiler rooms
2.1 General
2.1.1 Boiler rooms generally are to be separated from adjacent engine rooms by bulkheads. Unless these bulkheads are
watertight or tank bulkheads according to Section 11 or 12, the scantlings according to 2.2 are sufficient.
2.1.2 The bilges are to be separated from each other in such a way that no oil can pass from the boiler room bilge to
the engine room bilge. Bulkhead openings are to have hinged doors.
2.1.3 Where a close connection between engine and boiler room is advantageous in respect of supervision and safety,
complete bulkheads may be dispensed with, provided the conditions given in Rules for Machinery Installations, Volume
III, are complied with.
2.2 Scantlings
2.2.1 The thickness of watertight parts of the partition bulkheads is not to be less than 6,0 mm. The thickness or the
remaining parts may be 5 mm.
2.2.2 Platforms and decks below the boilers are to be made watertight; they are to be not less than 6,0 mm in thickness,
and are to be well supported.
2.2.3 Stiffeners spaced 900 mm apart are to be fitted. The section modulus of the stiffeners is not to be less than:
W = 12 @ R [cm3
]
R = unsupported span of stiffener [m].
Where the stiffener spacing deviates from 900 mm, the section modulus is to be corrected in direct proportion.
B. Ceiling
1. Bottom ceiling
1.1 Where in the holds of general cargo ships a tight bottom ceiling is to be fitted from board to board, the thickness
of a wooden ceiling shall not be less than 60 mm.
1.2 On single bottoms ceilings are to be removable for inspection of bottom plating at any time.
1.3 Ceilingsondoublebottomsaretobelaidonbattensnotlessthan12,5mmthickprovidingaclearspacefordrainage
of water or leakage oil. The ceiling may be laid directly on the inner bottom plating, if embedded in preservation and sealing
compound.
1.4 It is recommended to fit double ceilings under the hatchways.
1.5 The manholes are to be protected by a steel coaming welded around each manhole, fitted with a cover of wood
or steel, or by other suitable means.
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![C, D Section 21 - Hull Outfit21-4/21
4.3 Heated glass panes have to be in accordance with ISO 3434.
4.4 An equivalent thickness (ts) of laminated toughened safety glass is to be determined from the following formula:
ts =
5. Tests
Windows and side scuttles have to be tested in accordance with the respective ISO standards 1751 and 3903.
D. Scuppers, Sanitary Discharges and Freeing Ports
1. Scuppers and sanitary discharges
1.1 Scuppers sufficient in number and size to provide effective drainage of water are to be fitted in the weather deck
and in the freeboard deck within weathertight closed superstructures and deckhouses. Cargo decks and decks within closed
superstructuresaretobedrainedtothebilge.Scuppersfromsuperstructuresanddeckhouseswhicharenotclosedweathertight
are also to be led outside.
1.2 Scuppers draining spaces below the summer load line, are to be connected to pipes, which are led to the bilges
and are to be well protected.
1.3 Wherescupperpipesareledoutsidefromspacesbelowthefreeboarddeckandfromweathertightclosedsuperstructures
and deckhouses, they are to be fitted with non-return valves of automatic type, which can be operated from a position always
accessible and above the freeboard deck. Means showing whether the valves are open or closed (positive means of closing)
are to be provided at the control position.
1.4 Where the vertical distance from the summer load waterline to the inboard end of the discharge pipe exceeds 0,01
L, the discharge may have two automatic non-return valves without positive means of closing, provided that the inboard
valve is always accessible for examination, i.e., the valve is to be situated above the tropical or subdivision load line.
1.5 Where the vertical distance mentioned under 1.4 exceeds 0,02 L, a single automatic non-return valve, without
positive means of closing may be accepted. This relaxation is not valid for compartments below the freeboard deck of ships,
for which a flooding calculation in the damaged condition is required.
1.6 Scuppers and discharge pipes originating at any level and penetrating the shell either more than 450 mm below
the freeboard deck or less than 600 mm above the summer load water line are to be provided with a non-return valve at the
shell. This valve, unless required by 1.3, may be omitted if a heavy gauge discharge pipe is fitted.
1.7 Requirements for seawater valves related to operating the power-plant shall be observed see Rules for Machinery
Installations, Volume III, Section 11, I.3.
1.8 All valves including ship side valves required under 1.2 to 1.7 are to be of steel, bronze or other approved ductile
material. Ordinary casts iron is not acceptable. Pipe lines are to be of steel or similar material ( see Rules for Machinery
Installations, Volume III, Section 11).
1.9 Scuppersandsanitarydischargesshouldnotbefittedabovethelowestballastwaterlineinwayoflifeboatlaunching
positions or means for preventing any discharge of water into the life boats are to be provided for. The location of scuppers
and sanitary discharges is also to be taken into account when arranging gangways and pilot lifts.
2. Freeing ports
2.1 Where bulwarks on exposed portions of freeboard and/or superstructure decks form wells, ample provision is to
be made for rapidly freeing the decks of water.
2.2 Except as provided in 2.3 to 2.5 the minimum freeing port area on each side of the ship for each well on the
freeboard deck of a ship of type "B" is to be determined by the following formulae in cases where the sheer in way of the
well is standard or greater than standard :
A = 0,7 + 0,035 R [m2
] for R < 20 m
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-322-320.jpg)
![Section 21 - Hull Outfit D, E 21-5/21
= 0,07 R [m2
] for R > 20 m
R = length of bulwark [m]
Rmax = 0,7 L
The minimum area for each well on superstructure decks shall be one half of the area obtained by the formulae.
If the bulwark is more than 1,2 m in average height the required area is to be increased by 0,004 m2
per metre of length of
well for each 0,1 m difference in height.
If the bulwark is less than 0,9 m in average height, the required area may be decreased accordingly.
2.3 In ships with no sheer the area calculated according to 2.2 is to be increased by 50%. Where the sheer is less than
the standard the percentage shall be obtained by linear interpolation.
2.4 In ships of type "B with reduced freeboard" the freeing port area on the exposed freeboard deck is to be obtained
as follows :
- Where a combination of open rail and rigid bulwark is fitted, the length of the open rail is to be at least 50% of the length
of the exposed part of the freeboard deck.
- Where a continuous bulwark is fitted, the freeing port area is to be 25% of the total area of the bulwarks, where the
freeboard is reduced by not more than 60% of the difference between B and A tables. Where the freeboard is reduced
by more than 60% the area is to be not less than 33% of the total area of the bulwarks.
2.5 Where a ship is fitted with a trunk on the freeboard deck, which will not be take into account when calculating
thefreeboard,orwherecontinuousorsubstantiallycontinuoushatchwaysidecoamingsarefittedbetweendetachedsuperstructures
the minimum area of the freeing port openings is to be determined from Table 21.1.
2.6 In ships having open superstructures, adequate freeing ports are to be provided which guarantee proper drainage.
2.7 Where trunks are taken into account when calculating the freeboard an open rail is to be fitted in way of the trunk
for at least 50% of the length of the trunk.
As an equivalent, a continuous bulwark can be fitted with a continuous slot of 33% of the bulwark area.
2.8 The lower edges of the freeing ports shall be as near to the deck as practicable. Two thirds of the freeing port area
required shall be provided in the half of the well nearest to the lowest point of the sheer curve.
Table 21.1 - Minimum area of freeing ports
Breadth of hatchway or trunk in
relation to B [%]
Area of freeing ports in relation to the
total area of the bulwark [%] 1)
(each side separately)
40 or less
75 or more
20
10
1)
The area of freeing ports at intermediate breadth is to be obtained by linear interpolation
2.9 All such openings in the bulwarks shall be protected by rails or bars spaced approximately 230 millimeters apart.
Ifshuttersarefitted to freeing ports, ample clearance shallbe provided to preventjamming. Hingesshallhavepinsorbearings
of non-corrodible material.
2.10 Oncontainershipswithcontinuouslongitudinalhatchcoamings,wherewatermayaccumulatebetweenthe transverse
coamings, freeing ports are to be provided at both sides, with a minimum sectional area Aq of :
Aq = 0,07 @ bQ [m2
]
bQ = breadth of transverse box girder [m]
E. Air Pipes, Overflow Pipes, Sounding Pipes
1. Each tank is to be fitted with air pipes, overflow pipes and sounding pipes. The air pipes are in general to be led
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-323-320.jpg)
![E Section 21 - Hull Outfit21-6/21
to above the exposed deck. For the arrangement and scantlings of pipes see also Rules for Machinery Installations, Volume
III, Section 11,R. The height from the deck of the point where the water may have access is to be at least 760 mm on the
freeboard deck and 450 mm on a superstructure deck.
2. Suitable closing appliances are to be provided for air pipes, overflow pipes and sounding pipes, see also Rules
for Machinery Installations, Volume III, , Section 11, R. Where deck cargo is carried, the closing appliances are to be readily
accessible at all times. In ships for which flooding calculations are to be made, the ends of the air pipes are to be above the
damage waterline in the flooded condition. Where they immerge at intermediate stages of flooding, these conditions are to
be examined separately.
3. Closely under the inner bottom or the tank top, holes are to be cut into floor plates and side girders as well as into
beams, girders, etc., to give the air free access to the air pipes.
Besides, all floor plates and side girders are to be provided with limbers to permit the water or oil to reach the pump suctions.
4. Sounding pipes are to be extended to directly above the tank bottom. The shell plating is to be strengthened by
thicker plates or doubling plates under the sounding pipes.
5. Special strength requirements for fore deck fittings
5.1 General
The following strength requirements are to be observed to resist green sea forces for the items given below, located within
the forward quarter length:
– air pipes, ventilator pipes and their closing devices
Exempted from these requirements are air pipes, ventilator pipes and their closing devices of the cargo venting systems and
the inert gas systems of tankers.
5.2 Application
For ships that are contracted for construction on or after 1st
January 20042)
on the exposed deck over the forward 0,25 L,
applicable to:
– all ship types of seagoing service of length 80 m or more, where the height of the exposed deck in way of the item is
less than 0,1 L or 22 m above the summer load waterline, whichever is the lesser
5.3 Applied loading for air pipes, ventilator pipes and their closing devices
5.3.1 The pressures p [kN/m2
] acting on air pipes, ventilator pipes and their closing devices may be calculated from:
p = [kN/m2
]
D = density of sea water (1,025 t/m3
)
V = velocity of water over the fore deck-
= 13,5m/sec for d #0.5 # d1
= m/sec for 0.5 d1 # d # d1
d = distance from summer load waterline to exposed deck
d1 = 0.1L or 22m whichever is the lesser
Cd = shape coefficient
= 0,5 for pipes
= 0,8 for an air pipe or ventilator head of cylindrical form with its axis in the vertical direction
= 1,3 for air pipes or ventilator heads
2)
For ships contracted for construction prior to 1st
January 2004 refer to IACS UR S27 para 2.2.
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![Section 21 - Hull Outfit E 21-7/21
Cs = slamming coefficient
= 3,2
Cp = protection coefficient
= 0,7 for pipes and ventilator heads located immediately behind a breakwater or forecastle
= 1,0 elsewhere and immediately behind a bulwark
5.3.2 Forces acting in the horizontal direction on the pipe and its closing device may be calculated from 5.3.1 using
the largest projected area of each component.
5.4 Strength requirements for air pipes, ventilator pipes and their closing devices
5.4.1 Bending moments and stresses in air and ventilator pipes are to be calculated at critical positions:
– at penetration pieces
– at weld or flange connections
– at toes of supporting brackets
Bending stresses in the net section are not to exceed 0,8@Fy, where Fy is the specified minimum yield stress or 0,2 % proof
stress of the steel at room temperature. Irrespective of corrosion protection, a corrosion addition to the net section of 2,0 mm
is then to be applied.
5.4.2 Forstandardairpipesof760mmheightclosedbyheadsofnotmorethanthetabulatedprojectedarea,pipe thicknesses
and bracket heights are specified in Table 21.2. Where brackets are required, three or more radial brackets are to be fitted.
Brackets are to be of gross thickness 8 mm or more, of minimum length 100 mm, and height according to Table 21.2
but need not extend over the joint flange for the head. Bracket toes at the deck are to be suitably supported.
5.4.3 For other configurations, loads, according to 5.3 are to be applied, and means of support determined in order to
comply with the requirements of 5.4.1. Brackets, where fitted, are to be of suitable thickness and length according to their
height. Pipe thickness is not to be taken less than as indicated in Rules for Machinery Installations, Volume III, Section
11, Table 11.20a and 11.20b.
5.4.4 For standard ventilators of 900 mm height closed by heads of not more than the tabulated projected area, pipe
thicknesses and bracket heights are specified in Table 21.3. Brackets, where required are to be as specified in 5.4.2.
5.4.5 Forventilatorsofheightgreaterthan900mm,bracketsoralternativemeansofsupportaretobespecially considered.
Pipe thickness is not to be taken less than as indicated in Rules for Machinery Installations, Volume III, Section 11, Table
11.20a and 11.20b.
5.4.6 All component part and connectionsofthe air pipe or ventilator are to be capable of withstanding the loads defined
in 5.3.
5.4.7 Rotating type mushroom ventilator heads are unsuitable for application in the areas defined in 5.2.
Table 21.2 - 760 mm air pipe thickness and bracket standards
Nominal pipe diameter
[mm]
Minimum fitted 1)
gross
thickness
[mm]
Maximum projected area
of head
[cm2
]
Height2)
of brackets
[mm]
65A 6.0 –– 480
80A 6.3 –– 460
100A 7.0 –– 380
125A 7.8 –– 300
150A 8.5 –– 300
175A 8.5 –– 300
200A 8.5 3)
1900 300 3)
250A 8.5 3)
2500 300 3)
300A 8.5 3)
3200 300 3)
350A 8.5 3)
3800 300 3)
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![E, F Section 21 - Hull Outfit21-8/21
400A 8.5 3)
4500 300 3)
1)
See IACS Unified Interpretation LL 36.c
2)
Brackets see 5.4.2 need not extend over the joint flange for the head.
3)
Brackets are required where the as fitted (gross) thickness is less than 10,5 mm, or where the tabulated projected head area is exceeded.
Note:
For other air pipe heights, the relevant requirements of 5.4 are to be applied
Table 21.3 - 900 mm ventilator pipe thickness and bracket standards
Nominal pipe diameter
[mm]
Minimum fitted
gross thickness
[mm]
Maximum projected area
of head
[cm2
]
Height of brackets
[mm]
80A 6,3 –– 460
100A 7,0 –– 380
150A 8,5 –– 300
200A 8,5 550 ––
250A 8,5 880 ––
300A 8,5 1200 ––
350A 8,5 2000 ––
400A 8,5 2700 ––
450A 8,5 3300 ––
500A 8,5 4000 ––
Note:
For other ventilator heights, the relevant requirements of 5.4 are to be applied.
F. Ventilators
1. General
1.1 The height of the ventilator coamings on the exposed freeboard deck, quarter deck and on exposed superstructure
decks in the range 0,25 L from F.P. is to be at least 900 mm.
1.2 On exposed superstructure decks abaft 0,25 L from F.P. the coaming height is not to be less than 760 mm.
1.3 Ventilators of cargo holds are not to have any connection with other spaces.
1.4 The thickness of the coaming plates is to be 7,5 mm where the clear opening sectional area of the ventilator
coamings is 300 cm2
or less, and 10 mm where the clear opening sectional area exceeds 1600 cm2
. Intermediate values are
to be determined by direct interpolation. A thickness of 6 mm will generally be sufficient within not permanently closed
superstructures.
1.5 The thickness of ventilator posts should be at least equal to the thickness of coaming as per 1.4.
1.6 The wall thickness of ventilator posts of a clear sectional area exceeding 1600 cm2
is to be increased according
to the expected loads.
1.7 Generally, the coamings and posts shall pass through the deck and shall be welded to the deck plating from above
and below.
Where coamings or posts are welded onto the deck plating, fillet welds of a = 0,5 @ t0, subject to Section 19, B.3.3 should
be adopted for welding inside and outside.
1.8 Coamings and posts particularly exposed to wash of sea are to be efficiently connected with the ship's structure.
1.9 Coamings of a height exceeding 900 mm are to be specially strengthened.
1.10 Where the thickness of the deck plating is less than 10 mm, a doubling plate or insert plate of 10 mm thickness
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-326-320.jpg)
![Section 21 - Hull Outfit F, G 21-9/21
is to be fitted. Their side lengths are to be equal to twice the length or breadth of the coaming.
1.11 Wherebeams are pierced by ventilatorcoamings,carlingsofadequatescantlingsaretobefittedbetweenthebeams
in order to maintain the strength of the deck.
2. Closing appliances
2.1 Inlet and exhaust openings of ventilation systems are to be provided with easily accessible closing appliances,
which can be closed weathertight against wash of the sea. ln ships of not more than 100 m in length, the closing appliances
are to be permanently attached. In ships exceeding 100 m in length, they may be conveniently stowed near the openings to
which they belong.
2.2 Forventilatorpostswhichexceed4,5minheightabovethefreeboarddeckorraisedquarterdeckandaboveexposed
superstructuredecksforwardof0,25L fromF.P. andforventilatorpostsexceeding2,3minheightaboveexposedsuperstructure
decks abaft 0,25 L from F.P. closing appliances are required in special cases only.
2.3 For the case of fire draught-tight fire dampers are to be fitted.
3. For Special strength requirements for fore deck fittings, see E.5.
G. Stowage of Containers
1. General
1.1 All parts for container stowing and lashing equipment are to comply with the "Rules for the Stowage and Lashing
of Containers Aboard Ships". All parts which are intended to be welded to the ship's hull, including hatchcovers, are to be
made of materials complying with and tested in accordance with the Rules for Materials, Volume V.
1.2 Allequipmentondeckandintheholdsessentialformaintainingthesafetyoftheshipandwhicharetobeaccessible
at sea, e.g. fire fighting equipment, sounding pipes etc., should not be made inaccessible by containers or their stowing and
lashing equipment.
1.3 Fortransmitting the forces fromthe container stowing and lashing equipment into the ship's hull adequatewelding
connections and local reinforcements of structural members are to be provided (see also 2. and 3.).
1.4 The hatchway coamings are to be strengthened in way of the connections of transverse and longitudinal struts
of cell guide systems.
The cell guide systems are not permitted to be connected to projecting deck plating edges in way of the hatchways. Any flame
cutting or welding should be avoided, particularly at the deck rounding in the hatchway corners.
1.5 Where inner bottom, decks, or hatchcovers are loaded with containers, adequate substructures, e.g. carlings, half
heightgirdersetc.,aretobeprovidedandtheplatethicknessistobeincreased whererequired.Forwelded-inparts,seeSection
19, B.2.
2. Load assumptions
2.1 The scantlings of the local ship structures and of the container substructures are to be determined on the basis of
the Containers Stowage and Lashing Plans.
2.2 For determining scantlings the following design forces are to be used which are assumed to act simultaneously
in the centre of gravity of a stack :
ship's transverse (y-) direction:
0,5 g @ G [kN]
ship's vertical (z-) direction:
(1 + av) g @ G [kN]
G = stack mass [t]
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![G, H, J Section 21 - Hull Outfit21-10/21
av = see Section 4, C.1.1.
3. Permissible stresses
3.1 For hatchway covers in pos. 1 and 2 loaded with containers, the permissible stresses according to Section 17, C.2.
are to be observed.
3.2 The stresses in local ship structures and in substructure for containers as well as for cell guide systems and lashing
devices in the hatch covers of cargo decks are not to exceed the following values:
Fb = [N/mm2
]
J = [N/mm2
]
Fv = < [N/mm2
]
ReH = minimum nominal upper yield point of the material.
3.3 For dimensioning the double bottom in case of single point loads due to 20'- or 40'-containers, see Section 8,
B.8.2.
3.4 Where other structural members of the hull, e.g. frames, deck beams, bulkheads, hatchway coamings, bulwark
stays etc. are subjected to loads from containers, cell guide systems and container lashing devices, these members are to be
strengthened wherever necessary so that the actual stresses will not exceed those upon which the formulae in the respective
Sections are based.
H. Lashing Arrangements
Lashingeyesandholesaretobearrangedinsuchawayastonotundulyweakenthestructuralmembersofthehull.Inparticular
wherelashingsareattachedtoframes,theyaretobesoarrangedthatthebendingmomentintheframesisnotundulyincreased.
Where necessary, the frame is to be strengthened.
J. Car Decks
1. General
1.1 These Rules apply to movable as well as to removable car decks not forming part of the ship's structure.
1.2 The following information should be included in the plans to be submitted for approval :
- Scantlings of the car decks
- Masses of the car decks
- Number and masses of cars intended to be stowed on the decks
- Wheel loads and distance of wheels
- Connection of the car decks to the hull structure
- Moving and lifting gear of the car decks.
1.3 Car decks in accordance with these requirementsmaybemadeofhullstructuralsteel or of the following materials:
- Structural steel R St 37-2 (Fe 360 B) and St 52-3 (Fe 510 D1)
- Seawater resisting aluminium alloys
2. Design loads
2.1 For determining the scantlings of remaining component parts of the decks, the following loads are to be used:
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-328-320.jpg)
![Section 21 - Hull Outfit J 21-11/21
- Uniformly distributed load resulting from the mass of the deck and maximum number of cars to be carried. This
load is not to be taken less than 2,5 [kN/m2
.].
- Wheel load P
Where all wheels of one axle are standing on a deck girder or a deck beam, the axle load is to be evenly distributed
on all wheels.
Where not all of the wheels of one axle are standing on a deck girder or a deck beam, the following wheel loads are
to be used:
P = 0,5 x axle load for 2 wheels per axle
= 0,3 x axle load for 4 wheels per axle
= 0,2 x axle load for 6 wheels per axle.
Where no data is available, P is to be taken as 25 [kN].
2.2 For determining the scantlings of the suspensions, the increased wheel load in case of four and six wheels per
axle as per 2.1 need not be considered.
3. Plating
3.1 The thickness of the plating is to be determined accordingto the formulae as per Section 7, B.2. Where aluminium
alloy is used, the thickness is to be determined as per Section 2, D.1.
3.2 The thickness of plywood is to bedeterminedtaking into account a safety factor of 6 against the minimumultimate
strength of the material. Where plywood plates, supported on two sides only, are subjected to single loads, 1,45 times the
unsupported span may be taken as effective width of the plating.
4. Permissible stresses
4.1 In steel stiffeners and girders as well as in the steel structural elements of the suspensions, subjected to loads as
per 2. including the acceleration factor av according to Section 4, C.1.1 the following permissible stresses are to be observed:
Normal and bending stresses (tension and compression):
F < [N/mm2
]
Sheer stresses:
J < [N/mm2
]
Combined stresses:
Fv = # [N/mm2
]
k = material factor according to Section 2, B.2.
= 0,72 for Fe 510 D1 (St 52-3)
= 1,0 for Fe 360 B (R St 37-2)
4.2 Wherealuminiumalloysareused,thepermissiblestressesmaybederivedfrommultiplyingthepermissiblestresses
specified for ordinary hull structural steel by the factor 1/kAR (kAR = material factor for aluminium according to Section 2,
D.1.).
5. Permissible deflection
5.1 The deflection of girders subjected to loads stipulated under 2. is not to exceed:
f =
R = unsupported span of girder.
5.2 An adequate safety distance should be maintained between the girders of a loaded deck and the top of car stowed
on the deck below.
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-329-320.jpg)
![J, K, L Section 21 - Hull Outfit21-12/21
6. Buckling
The buckling strength of girders is to be proved according to Section 3, F., if required.
K. Life Saving Appliances
1. It is assumed that for the arrangement and operation of life boats and other life saving appliances the regulations
of SOLAS 74 or those of the competent Authority are complied with.
2. The design appraisal and testing of life boats with their launching appliances and of other life saving appliances
are not part of Classification.
However, approval of the hull structure in way of the launching appliances taking into account the forces from the above
appliances is part of classification.
Part of Classification also is the survey of the life saving appliances and their launching appliances with regard to their proper
condition and functioning within the scope of the class renewal surveys.
L. Signal and Radar Masts
1. General
1.1 Drawings of masts, mast substructures and hull connections are to be submitted for approval.
1.2 Loosecomponentpartsaretocomplywiththe"RegulationsfortheConstructionandSurveyofLiftingAppliances".
They are to be tested by BKI.
1.3 Other masts than covered by 2. and 3. as well as special designs, shall as regards dimensions and construction
in each case be individually agreed with BKI.
2. Single tubular masts
The following requirements applytotubular or equivalent rectangular sections made of steel with an ultimate tensile strength
of 400 N/mm², which are designed to carry only signals (navigation lanterns, flag and day signals).
2.1 Stayed masts
2.1.1 Stayed masts may be constructed as simply supported masts (rocker masts) or may be supported by one or more
decks (constrainedt masts).
2.1.2 The diameterofstayed steelmastsintheuppermosthousingistobeatleast20mmforeach1mlengthofhounding.
The length of the mast top above the hounds is not to exceed 1/3 Rw (Rw denotes the hounding [m]).
2.1.3 Mast according to 2.1.2 may be gradually tapered towards the hounds to 75% of the diameter at the uppermost
housing. The plate thickness is not to be less than 1/70 of the diameter or at least 4 mm, see 4.1.
2.1.4 Wire ropes for shrouds are to be thickly galvanized. It is recommended to use wire ropes composed of a minimum
number of thick wires, as for instance a rope construction 6 x7 with a tensile breaking strength of 1570 N/mm2
.
2.1.5 Where masts are stayed forward and aft by one shroud on each side of the ship, steel wire ropes are to be used
with a tensile breaking strength of 1570 N/mm2
according to Table 21.4.
Table 21.4 - Rope and sackles of stayed steel masts
h [m] 6 8 10 12 14 16
Rope diameter [mm] 14 16 18 20 22 24
Nominal size of shackle, rigging screw, rope socket 2,5 3 4 5 6 8
h = height of hound over the hauling of the shrouds
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-330-320.jpg)
![Section 21 - Hull Outfit L 21-13/21
2.1.6 Where steel wire ropes according to Table 21.2 are used, the following conditions apply:
b > 0,3 h
0,15 h < a < b
a = the distance of the hauling points of the shrouds from the transverse section through the hound.
b = the distance of the hauling points of the shrouds from the longitudinal section through the hound.
Alternative arrangements of staying are to be of equivalent stiffness
2.2 Unstayed masts
2.2.1 Unstayed masts may be completely constrained in the uppermost deck or be supported by two or more decks. (In
general, the fastenings of masts to the hull of a ship should extend over at least one deck height).
2.2.2 The scantlings for unstayed steel masts are given in the Table 21.5
Table 21.5 - Dimensions of unstayed steel masts
Length of mast Rm [m] 6 8 10 12 14
Dxt [mm] 160 x@4 220 x 4 290 x 4,5 360 x 5,5 430 x 6,5
Rm = length of mast from uppermost support to the top
D = diameter of mast at uppermost support
t = plate thickness of mast
2.2.3 The diameter of masts may be gradually tapered to D/2 at the height of 0,75 Rm.
3. Box girder and frame work masts
3.1 For dimensioning the dead loads, acceleration forces and wind loads are to be considered.
3.2 Where necessary additional loads e. g. loads caused by the sea fastening of crane booms or tension wires are also
to be considered.
3.3 Thedesignloadsfor3.1and3.2aswellastheallowablestressescanbetakenfromthe"RegulationsfortheConstruction
and Survey of Lifting Appliances."
3.4 Single tubular masts mounted on the top may be dimensioned according to 2.
3.5 In case of thin walled boxgirder masts stiffeners and additional buckling stiffeners may be necessary.
4. Structural details
4.1 Steelmastsclosedall-roundshallhaveawallthicknessofatleast4mm.Formastsnotclosedall-roundtheminimum
wall thickness is 6 mm. For masts used as funnels a corrosion addition of at least 1 mm is required.
4.2 The ship’s side foundations are to be dimensioned in accordance with the acting forces.
4.3 Doublingplatesatmastfeetarepermissibleonlyforthetransmissionofcompressiveforcessincetheyaregenerally
not suitable for the transmission of tensile forces or bending moments.
4.4 In case of tubular constructions all welded fastenings and connections shall be of full penetration weld type.
4.5 If necessary, slim tubes are to be additionally supported in order to avoid vibrations.
4.6 The dimensioning normally does not require a calculation of vibrations. However, in case of undue vibrations
accuring during the ship’s trial a respective calculation will be required.
4.7 For determining scantlings of masts made from aluminium or austenitic steel, the requirements given in Section
2, D. and E. apply.
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![A,B Section 22 - Structural Fire Protection on Board Seagoing Ships22-2/48
ceilings, surface materials and not readily ignitable deck coverings shall be of approved type.
1.7 Forregulationsonfirealarmsystemsandonfireextinguishingarrangements,seeRulesforMachineryInstallations,
Volume III, Section 12.
1.8 IACS Unified Interpretations have to be observed and shall be complied with.
B. Regulations on Fire Protection for Passenger Ships carrying more than 36 Passengers
1. Materials
1.1 Thehull,decks,structuralbulkheads,superstructuresanddeckhousesaretobeofsteelorotherequivalentmaterials
(Aluminium alloy suitably insulated).
1.2 Components made from aluminium alloys require special treatment, with regard to the mechanical properties
of the material in case of temperature increase. In principle, the following is to be observed:
1.2.1 The insulation of "A" or "B" class divisions shall be such that the temperature of the structural core does not rise
more than 200EC above the ambient temperature at any time during the applicable fire exposure to the standard fire test.
1.2.2 Special attention shall be given to the insulation of aluminium alloy components of columns, stanchions and other
structural members required to support lifeboat and liferaft stowage, launching and embarkation areas, and "A" and "B"
class divisions to ensure:
that for such members supporting lifeboat and liferaft areas and "A"class divisions, the temperature rise limitation specified
in1.2.1shallapplyattheendofonehour;andthatfor suchmembers required to support "B"class divisions, the temperature
rise limitation specified in 1.2.1 shall apply at the end of half an hour.
1.2.3 Crowns and casings of machinery spaces of category A shall be of steel construction and be insulated as required
by Table 22.1 as appropriate. Openings therein, if any, shall be suitably arranged and protected to prevent the spread of
fire.
2. Main vertical zones and horizontal zones
2.1 The hull, superstructures and deckhouses are to be subdivided into main vertical zones the average length and
width of which on any deck is generally not to exceed 40 m.
Subdivision is to be effected by "A-60" class divisions. Steps and recesses shall be kept to a minimum. Where a category
4.3 [5], 4.3 [9] or 4.3 [10] space is on one side of the division or where fuel oil tanks are on both sides of the division the
standard may be reduced to "A-0".
As far as practicable, the bulkheads forming the boundaries of the main vertical zones above the bulkhead deck shall be
in line with watertight subdivision bulkheads situated immediately below the bulkhead deck. The length and width of main
vertical zones may be extended to a maximum of 48 m in order to bring the ends of main vertical zones to coincide with
subdivision watertight bulkheads or in order to accommodatea large public space extending for the whole length of the main
vertical zone provided that the total area of the main vertical zone is not greater than 1600 m2
on any deck. The length or
width of a main vertical zone is the maximum distance between the furthermost points of the bulkheads bounding it.
The divisions are to be extended from deck to deck and to the shell or other boundaries. At the edges insulating bridges are
to be provided where required.
2.2 On ships designed for specialpurposes(automobileor railroad car ferries), where the provision of main vertical
zone bulkheads would defeat the purpose for which the ship is intended, equivalent means for controlling and limiting a fire
aretobeprovidedandspecificallyapproved.Servicespacesandshipstoresshallnotbelocatedonro-rodecksunlessprotected
in accordance with the applicable regulations.
3. Bulkheads within main vertical zones
3.1 All bulkheads which are not required to be "A" class divisions shall be at least "B" class or "C" class divisions
as prescribed in Table 22.1. All such divisions may be faced with combustible materials.
3.2 All bulkheads required to be "B"class divisionsshall extend from deck to deck and to the shell or other boundaries
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-342-320.jpg)
![B Section 22 - Structural Fire Protection on Board Seagoing Ships22-4/48
Table 22.1 Bulkheads not bounding either main vertical zones or horizontal zones
Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
Control stations [1] B-01
A-0 A-0 A-0 A-0 A-60 A-60 A-60 A-0 A-0 A-60 A-60 A-60 A-60
Stairways [2] A-01
A-0 A-0 A-0 A-0 A-15 A-15 A-03
A-0 A-15 A-30 A-15 A-30
Corridors [3] B-15 A-60 A-0 B-15 B-15 B-15 B-15 A-0 A-15 A-30 A-0 A-30
Evacuation stations and ex-
ternal escape routes
[4] A-0 A-
602,4
A-
602,4
A-
602,4
A-04
A-0 A-602
A-602
A-602
A-602
Open deck spaces [5] S A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0
Accommodation spaces
of minor fire risk
[6] B-0 B-0 B-0 C A-0 A-0 A-30 A-0 A-30
Accommodation spaces
of moderate fire risk
[7] B-0 B-0 C A-0 A-15 A-60 A-15 A-60
Accommodation spaces
of greater fire risk
[8] B-0 C A-0 A-30 A-60 A-15 A-60
Sanitary and similar spaces [9] C A-0 A-0 A-0 A-0 A-0
Tanks, voids and auxiliary
machinery spaces having
little or no fire risk
[10] A-01
A-0 A-0 A-0 A-0
Auxiliary machinery spaces,
cargo spaces, cargo and
other oil tanks and other
similar spaces of moderate
fire risk
[11] A-01
A-0 A-0 A-15
Machinery spaces and main
galleys
[12] A-01
A-0 A-60
Store-rooms, workshops,
pantries etc.
[13] A-01
A-0
Other spaces in which
flammable, liquids are
stowed
[14] A-30
Notes to be applied to Tables 22.1 to 22.2, as appropriate.
1. Whereadjacentspacesareinthesamenumericalcategoryandsuperscript1appears,abulkheadordeckbetweensuchspaces
need not be fitted. For example, in category [12] a bulkhead need not be required between a galley and its annexed pantries
provided the pantry bulkheads and decks maintain the integrity of the galley boundaries. A bulkhead is, however, required
between a galley and a machinery space even though both spaces are in category [12].
2. The ship's side, to the waterline in the lightest seagoing condition, superstructure and deckhouse sides situated below and
adjacent to the liferafts and evacuation slides may be reduced to "A-30"
3. Wherepublictoiletsareinstalledcompletelywithinthestairwayenclosure,thepublictoiletbulkheadwithinthestairwayenclosure
can be of "B" class integrity.
4. Where spaces of category [6], [7], [8] and [9] are located completely within the outer perimeter of the muster station, the
bulkheads of these spaces are allowed to be of "B-0" class integrity. Control positions for audio, video and light installations
may be considered as part of the muster station.
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![Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-5/48
Table 22.2 Decks not forming steps in main vertical zones nor bounding zones
Spaces above
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
Spaces below
Control stations [1] A-30 A-30 A-15 A-0 A-0 A-0 A-15 A-30 A-0 A-0 A-0 A-60 A-0 A-60
Stairways [2] A-0 A-0 n A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-30 A-0 A-30
Corridors [3] A-15 A-0 A-01
A-60 A-0 A-0 A-15 A-15 A-0 A-0 A-0 A-30 A-0 A-30
Evacuation stations and ex-
ternal escape routes
[4] A-0 A-0 A-0 A-0 n A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0
Open deck spaces [5] A-0 A-0 A-0 A-0 n A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0
Accommodation spaces of
minor fire risk
[6] A-60 A-15 A-0 A-60 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0
Accommodation spaces of
moderate fire risk
[7] A-60 A-15 A-15 A-60 A-0 A-0 A-15 A-15 A-0 A-0 A-0 A-0 A-0 A-0
Accommodation spaces of
greater fire risk
[8] A-60 A-15 A-15 A-60 A-0 A-15 A-15 A-30 A-0 A-0 A-0 A-0 A-0 A-0
Sanitary and similar spaces [9] A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0
Tanks, voids and auxiliary
machinery spaces having
little or no fire risk
[10] A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-01
A-0 A-0 A-0 A-0
Auxiliary machinery spaces,
cargo spaces, cargo and
other oil tanks and other
similar spaces of moderate
fire risk
[11] A-60 A-60 A-60 A-60 A-0 A-0 A-15 A-30 A-0 A-0 A-01
A-0 A-0 A-30
Machinery spaces and main
galleys
[12] A-60 A-60 A-60 A-60 A-0 A-60 A-60 A-60 A-0 A-0 A-30 A-301
A-0 A-60
Store-rooms, workshops,
pantries etc.
[13] A-60 A-30 A-15 A-60 A-0 A-15 A-30 A-30 A-0 A-0 A-0 A-0 A-0 A-0
Other spaces in which
flammable, liquids are
stowed
[14] A-60 A-60 A-60 A-60 A-0 A-30 A-60 A-60 A-0 A-0 A-0 A-0 A-0 A-0
See notes under Table 22.1
[1] Control stations
Spaces containing emergency sources of power and lighting. Wheelhouse and chartroom. Spaces containing the ship's
radio equipment. Fire control stations. Control room for propulsion machinery when located outside the propulsion
machinery space.Spacescontainingcentralizedfirealarmequipment.Spacescontaining centralized emergency public
address system stations and equipment.
[2] Stairways
Interior stairways, lifts, totally enclosed emergency escape trunks and escalators (other than those wholly contained
within the machinery spaces) for passengers and crew and enclosures thereto. In this connection, a stairway which
is enclosed at only one level shall be regarded as part of the space from which it is not separated by a fire door.
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[3] Corridors
Passenger and crew corridors and lobbies.
[4] Evacuation stations and external escape routes.
Survival craft stowage area.
Open deck spaces and enclosed promenades forming lifeboat and liferaft embarkation and lowering stations.
Assembly stations, internal and external.
External stairs and open decks used for escape routes.
The ship's side to the waterline in the lightest seagoing condition, superstructure and deck house sides situated below
and adjacent to the liferaft's and evacuation slide's embarkation areas.
[5] Open deck spaces
Open deck spaces and enclosed promenades clear of lifeboat and liferaft embarkation and lowering stations. To be
considered in this category, enclosed promenades shall have no significant fire risk, meaning that furnishings shall
be restricted to deck furniture. In addition, such spacesshall be naturally ventilated by permanent openings. Air spaces
(the space outside superstructures and deckhouses).
[6] Accommodation spaces of minor fire risk
Cabins containing furniture and furnishings of restricted fire risk. Offices and dispensaries containing furniture and
furnishings of restricted fire risk. Public spaces containing furniture and furnishings of restricted fire risk and having
a deck area of less than 50 m2
.
[7] Accommodation spaces of moderate fire risk
Spacesasincategory [6] above butcontaining furnitureandfurnishings of other than restricted fire risk. Public spaces
containing furniture and furnishings of restricted fire risk and having a deck area of 50 m2
or more. Isolated lockers
andsmallstore-roomsinaccommodationspaceshavingareaslessthan4m2
(inwhichflammableliquidsarenotstowed).
Sale shops. Motion picture projection and film stowage rooms. Diet kitchens (containing no open flame). Cleaning
gear lockers (in which flammable liquids are not stowed). Laboratories (in which flammable liquids are not stowed).
Pharmacies.Smalldryingrooms(havingadeckareaof4m2
orless).Specierooms,operatingrooms, electricaldistribution
boards (see 4.3.2 and 4.3.3).
[8] Accommodation spaces of greater fire risk
Public spaces containing furniture and furnishings of other than restricted fire risk and having a deck area of 50 m2
or more. Barber shops and beauty parlours. Saunas.
[9] Sanitary and similar spaces
Communal sanitary facilities, showers, baths, water closets, etc. Small laundry rooms. Indoor swimming pool area.
Isolated pantries containing no cooking appliances in accommodation spaces.
Private sanitary facilities shall be considered a portion of the space in which they are located.
[10] Tanks, voids and auxiliary machinery spaces having little or no fire risk.
Watertanksformingpartoftheship'sstructure.Voidsandcofferdams.Auxiliarymachineryspaceswhichdonotcontain
machinery having a pressure lubrication system and where storage of combustibles is prohibited, such as:
Ventilationandair-conditioningrooms;windlassroom;steeringgearroom;stabilizerequipmentroom;electricalpropulsion
motor room; rooms containing section switchboards and purely electrical equipment other than oil-filled electrical
transformers(above10kVA);shaftalleysandpipetunnels;spacesforpumpsandrefrigerationmachinery(nothandling
or using flammable liquids).
Closed trunks serving the spaces listed above. Other closed trunks such as pipe and cable trunks.
[11] Auxiliary machinery spaces, cargo spaces, cargo and other oil tanks and other similar spaces of moderate fire risk
Cargo oil tanks. Cargo holds, trunkways and hatchways. Refrigerated chambers. Oil fuel tanks (where installed in a
separatespacewithnomachinery).Shaftalleysandpipetunnelsallowingstorageofcombustibles. Auxiliary machinery
spacesasincategory[10] whichcontainmachineryhavingapressurelubricationsystemorwherestorageofcombustibles
ispermitted.Oilfuelfillingstations.Spacescontainingoil-filledelectricaltransformers (above10kVA).Spacescontaining
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![Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-7/48
turbine and reciprocating steam engine driven auxiliary generators and small internal combustion engines of power
output up to 110 kW driving generators, sprinkler, drencher or fire pumps, bilge pumps, etc. Closed trunks serving
the spaces listed above.
[12] Machinery spaces and main galleys
Mainpropulsionmachineryrooms (otherthanelectricpropulsionmotorrooms)andboilerrooms.Auxiliarymachinery
spaces other than those in categories [10] and [11] whichcontain internal combustion machinery or other oil-burning,
heating or pumping units. Main galleys and annexes. Trunks and casings to the spaces listed above.
[13] Store-rooms, workshops, pantries, etc.
Main pantries not annexed to galleys. Main laundry. Large drying rooms (having a deck area of more than 4 m2
).
Miscellaneous stores. Mail and baggage rooms. Garbage rooms. Workshops (not part of machinery spaces. galleys,
etc.), lockers and store-rooms having areas greater than 4 m2
, other than those spaces which have provisions for the
storage of flammable liquids.
[14] Other spaces in which flammable liquids are stowed
Lamp rooms. Paint rooms. Store-rooms containing flammable liquids (including dyes, medicines, etc.). Laboratories
(in which flammable liquids are stowed).
4.3.1 In respect of category [5] spaces BKI shall determine whether the insulation values in Table 22.1 shall apply to
ends of deckhouses and superstructures, and whether the insulation values in Table 22.2 shall apply to weather decks.
Innocase shallthe requirements ofcategory [5] ofTables 22.1and22.2necessitate enclosure ofspaces whichinthe opinion
of BKI need not be enclosed.
4.3.2 Electricaldistributionboardsmaybelocatedbehindpanels/liningswithinaccommodationspacesincluding stairway
enclosures, without the need to categorize the space, provided no provision for storage is made.
4.3.3 If distribution boards are located in an identifiable space having a deck area of less than 4 m², this space shall
be categorized in [7].
4.4 Continuous "B" class ceilings or linings, in association with the relevant decks or bulkheads, may be accepted
as contributing wholly or in part, to the required insulation and integrity of a division.
4.5 At intersections and terminal points of the required fire insulation constructions due regard is to be paid to the
effect of thermal bridges. In order to avoid this, the insulation of a deck or bulkhead shall be carried past the intersection
or terminal point for a distance of at least 450 mm.
5. Protection of stairways and lifts in accommodation and service spaces
5.1 Allstairwaysinaccommodationandservicespacesaretobeofsteelframeorotherapprovedequivalentconstruction;
they are to be arranged within enclosures formed by "A" Class division, with effective means of closure for all openings.
The following exceptions are admissible:
5.1.1 Astairwayconnectingonlytwodecksneednotbeenclosed,providedthattheintegrityofthepierceddeckismaintained
by suitable bulkheads or doors at one of the two decks. When a stairway is closed at one ‘ween deck space, the stairway
enclosure shall be protected in accordance with the tables for decks.
5.1.2 Stairways fitted within a closed public space need not be enclosed.
5.2 Stairway enclosures are to be directly accessible from the corridors and of sufficient area to prevent congestion,
having in mind the number of persons likely to use them in an emergency. Within the perimeter of such stairway enclosures,
onlypublictoilets,lockersofnon-combustiblematerialprovidingstorageforsafetyequipmentandopeninformationcounters
are permitted. Only public spaces, corridors, public toilets, special category spaces, other escape stairways required by
12.3.3 and external areas are permitted to have direct access to these stairway enclosures.
Small corridors or lobbies used to separate an enclosed stairway from galleys or main laundries may have direct access
to the stairway provided they have a minimum deck area of 4,5 m², a width of no less than 900 mm and contain a fire hose
station.
5.3 Lift trunks shall be so fitted as to prevent the passage of smoke and flame from one 'tweendeck to another and
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10.7.5 bedding components shall have qualities of resistance to the ignition and propagation of flame 13)
.
10.8 Paints,varnishesandotherfinishesusedonexposedinteriorsurfaces,includingcabinbalconieswiththeexclusion
of natural hard wood decking systems, shall not be capable of producing excessive quantities of smoke and toxic products
14)
.
10.9 Primary deck coverings, if applied within accommodation and service spaces and control stations or if applied
on cabin balconies, shall be of approved material which will not readily ignite, or give rise to smoke or toxic or explosive
hazards at elevated temperatures 15)
.
10.10 Wastereceptaclesshallbeconstructedofnon-combustiblematerialswithnoopeningsinthesidesorbottom. Containers
ingalleys,pantries,bars,garbagehandlingorstoragespacesandincineratorroomswhichareintendedpurelyforthecarriage
of wet waste, glass bottles and metal cans may be constructed of combustible materials.
11. Details of construction
11.1 Inaccommodationandservicespaces,controlstations,corridorsandstairways,airspacesenclosedbehindceilings,
panellingor linings shall be suitably divided by close fittingdraught stops not more than 14 m apart. In the vertical direction,
such enclosed air spaces, including those behind linings of stairways, trunks, etc. shall be closed at each deck.
11.2 The construction of ceilings and bulkheads shall be such that it will be possible, without impairing the efficiency
of the fire protection, for the fire patrols to detect any smoke originating in concealed and inaccessible spaces.
11.3 Non-load bearing partial bulkheads separating adjacent cabin balconies shall be capable of being opened by
the crew from each side for the purpose of fighting fires.
11.4 The cargo holds and machinery spaces shall be capable of being effectively sealed such as to prevent the inlet
of air. Doors leading to machinery spaces of category A are to be provided with self-closing devices and 2 securing devices.
Allothermachineryspaces,whichareprotectedbya gas fire extinguishingsystem,aretobeequippedwithself-closingdoors.
11.5 Helicopter decks shall be of a steel or steel equivalentfire-resistant construction. If the space below the helicopter
deck forms the deckhead of a deckhouse or superstructure, it shall be insulated to "A-60" class standard. If an aluminium
or other low melting metal construction will be allowed, the following provisions shall be satisfied:
11.5.1 If the platform is cantilevered over the side of the ship, after each fire on the ship or on the platform, the platform
shall undergo a structural analysis to determine its suitability for further use.
11.5.2 Iftheplatformislocatedabovetheship'sdeckhouseorsimilarstructure,thefollowingconditionsshallbesatisfied:
11.5.2.1 The deckhouse top and bulkheads under the platform shall have no openings;
11.5.2.2 All windows under the platform shall be provided with steel shutters;
11.5.2.3 Therequiredfire-fightingequipmentshallbein accordance withthe requirementsofRulesforMachineryInstallations,
Volume III, Section 12.
11.5.2.4 After each fire on the platform or in close proximity, the platform shall undergo a structural analysis to determine
its suitability for further use.
11.6 Construction and arrangement of saunas
11.6.1 Theperimeter ofthesaunashallbeof“A”class boundariesandmayincludechangingrooms,showersand toilets.
The sauna shall be insulated to A-60 standard against other spaces except those inside the perimeter and spaces of category
[5], [9] and [10].
13)
Reference is made to the Fire Test Procedure Code, Annex 1, Part 9, adopted by IMO by Resolution MSC 61(67).
14)
Reference is made to the Fire Test Procedure Code, Annex 1, Part 2, adopted by IMO by Resolution MSC 61(67).
15)
Reference is made to the Fire Test Procedure Code, Annex 1, Part 6, adopted by IMO by Resolution MSC.61(67).
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of stairways serving this deck.
12.3.3.4 Stairways shall not exceed 3,5 m in vertical rise without the provision of a landing and shall not have an angle
of inclination greater than 45E.
12.3.3.5 Landings at each deck level shall be not less than 2 m2
in area and shall increase by 1 m2
for every 10 persons
provided for in excess of 20 persons but need not exceed 16 m2
, except for those landings servicing public spaces having
direct access onto the stairway enclosure.
12.3.4 Stairways serving only a space and a balcony in that space shall not be considered as forming one of the means
of escape.
12.3.5 Acorridor,lobby,orpartofacorridorfromwhichthereisonlyonerouteofescapeshallnotbepermitted.Dead–end
corridorsusedinserviceareaswhicharenecessaryforthepracticalutilityoftheship,suchasfueloilstationsandathwartship
supply corridors, shall be permitted, provided such dead-end corridors are separated from crew accommodation areas and
are inaccessible from passenger accommodation areas. Also, a part of the corridor that has a depth not exceeding its width
is considered a recess or local extension and is permitted.
12.3.6 In addition to the emergency lighting (see also Rules for Electrical Installations, Volume IV, Section 3 and 10),
the means of escape including stairways and exits, shall be marked by lighting or photoluminescent strip indicators placed
not more than 0,3 m above the deck at all points of the escape route including angles and intersections. The marking shall
enable passengers to identify all the routes of escape and readily identify the escape exits. If electric illumination is used,
it shall be supplied by the emergency source of power and it shall be so arranged that the failure of any single light or cut
in a lighting strip, will not result in the marking being ineffective. Additionally, all escape route signs and fire equipment
locationmarkingsshallbeofphotoluminescentmaterialormarkedbylighting. Suchlightingorphotoluminescentequipment
shall be of an approved type16)
.
12.3.7 The requirement of 12.3.6 shall also apply to the crew accommodation areas.
12.3.8 PublicSpacesspanningthree ormoredecksandcontaincombustiblessuchas furniture and enclosed spaces such
as shops, offices and restaurants shall have at each level withinthe space two means of escape, one of which shall have direct
access to an enclosed vertical means of escape as mentioned under 12.3.3.
12.4 Ifaradiotelegraphstationhasnodirectaccesstotheopendeck, twomeansofescapefromoraccesstosuchstation
shall be provided, one of which may be a porthole or window of sufficient size or another means.
12.5 In special category spaces the number and disposition of the means of escape both below and above the bulkhead
deck shall be satisfactory as mentioned under 12.3.1, .2 and .3.
12.6 Two means of escape shall be provided from each machinery space. In particular, the following provisions shall
be complied with:
12.6.1 Where the space is below the bulkhead deck the two means of escape shall consist of either:
12.6.1.1 Two sets of steel ladders as widely separated as possible, leading to doors in the upper part of the space similarly
separated and from which access is provided to the appropriate lifeboat and liferaft embarkation decks. One of these ladders
shall be located within a protected enclosure having fire integrity, including insulation values, in accordance with the
Tables 22.1and22.2foracategory[2] space,fromthelowerpartofthespacetoasafepositionoutsidethespace.Self-closing
doors of the same fire integrity standards shall be fitted in the enclosure. The ladder shall be fixed in such a way that heat
isnottransferredintotheenclosurethroughnon-insulatedfixingpoints.Theprotectedenclosureshallhaveminimuminternal
dimensions of at least 800 mm × 800 mm, and shall have emergency lighting provisions, or
12.6.1.2 One steel ladder leading to a door in the upper part of the space from which access is provided to the embarkation
deck and additionally, in the lower part of the space and in a position well separated from the ladder referred to, a steel
door capable of being operated from each side and which provides access to a safe escape route from the lower part of the
space to the embarkation deck.
12.6.2 Where the space is above the bulkhead deck, two means of escape shall be as widely separated as possible and
the doors leading from such means of escape shall be in a position from which access is provided to the appropriate lifeboat
and liferaft embarkation decks. Where such escapes require the use of ladders these shall be of steel.
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12.7.10 Escape routes are to be evaluated by an evacuation analysis early in the design process 17)
.
Theanalysisshallbeusedtoidentifyandeliminate,asfaraspracticable,congestionwhichmaydevelopduringanabandonment,
due to normal movement of passengers and crew along escape routes, including the possibility that crew may need to move
along these routes in a direction opposite the movement of passengers. In addition, the analysis shall be used to demonstrate
the escape arrangements are sufficiently flexible to provide for the possibility that certain escape routes, assembly stations,
embarkation stations or survival craft may not be available as a result of a casualty.
12.7.11 Designatedwalkwaystothemeansofescapewithabreadthofatleast600mmshallbeprovidedinspecial category
and open ro-ro spaces to which any passengers carried have access.
12.7.12 At least two means of escape shall be provided in ro-ro spaces where the crew are normally employed. The escape
routes shall provide safe escape to the lifeboat and liferaft embarkation decks and shall be located at the fore and aft ends
of the space.
13. Fixed fire detection and fire alarm systems and automatic sprinkler, fire detection and fire alarm systems.
13.1 Any ship shall be equipped with:
13.1.1 Anautomaticsprinkler,firedetectionandfirealarmsysteminallservicespaces,controlstationsandaccommodation
spaces, including corridors and stairways (see also Rules for Machinery Installations, Volume III, Section.12); and
13.1.2 A fixed fire detection and alarm system so installed and arranged as to provide smoke detection in service spaces,
control stations and accommodation spaces, including corridors and stairways (see also Rules for Machinery Installations,
Volume III, Section 12).
13.2 Controlstationswherewatermaycausedamagetoessentialequipmentmaybefittedwithafixedfire-extinguishing
system of another type (see also Rules for Machinery Installations, Volume III, Section 12).
13.3 Cabinbalconiesshallbeequippedwithafixedfiredetectionandfirealarmsystemandafixedpressure water-spraying
system(seealsoRules for Machinery Installations, Volume III, Section 12), whenfurniture andfurnishingsonsuchbalconies
are not complying with 10.7.
13.4 Smoke detectors need not be fitted in private bathrooms and galleys. Spaces having little or no fire risk such as
voids, public toilets andsimilar spacesneednotbefittedwithanautomaticsprinkler,orfixedfiredetectionandalarmsystem.
14. Protection of vehicle, special category and ro-ro spaces
14.1 The subdivision of such spaces in main vertical zones would defeat their intended purpose. Therefore equivalent
protection shall be obtained in such spaces on the basis of a horizontal zone concept. A horizontal zone may include special
category and ro-ro spaces on more than one deck provided that the total overall clear height for vehicles does not exceed
10 m, whereas the total overall clear height is the sum of distances between deck and web frames of the decks forming the
horizontal zone.
14.2 Structural Protection
The boundary bulkheads and decks of special category spaces and ro-ro spaces shall be insulated to "An60" class standard.
However, where a category 4.3 [5],4.3 [9]or 4.3 [10] space is on one side of the division the standard may be reduced to
"A-0". Where fuel oil tanks are below a special category space, the integrity of the deck between such spaces may be reduced
to "A-0" standard. Indicators shall be provided on the navigating bridge which shall indicate when any fire door leading
to or from the special category space is closed.
14.3 Fixed fire-extinguishing system
14.3.1 Vehicle spaces and ro-ro spaces which are not special category spaces and are capable of being sealed from a
location outside of the cargo spaces shall be fitted with a fixed gas fire-extinguishing system of an approved type (see
also Rules for Machinery Installations, Volume III, Section 12).
14.3.2 Ro-roandvehiclespacesnotcapableofbeingsealedandspecialcategoryspacesshallbefittedwithafixed pressure
17)
Reference is made to the Interim Guidelines for evacuation analyses for new and existing passenger ships adopted by IMO by
MSC/Circ. 1238.
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zone provided that the total area of the main vertical zone is not greater than 1600 m2
on any deck. The length or width of
a main vertical zone is the maximum distance between the furthermost points of the bulkheads bounding it. The divisions
are to extend from deck to deck and to the shell or other boundaries and shall have insulation values in accordance with
Table 22.3. At the edges insulating bridges are to be provided where required.
2.2 Where a main vertical zone is subdivided by horizontal "A" class divisions into horizontal zones for the purpose
of providing an appropriate barrier between sprinklered and non-sprinklered zones of the ship the divisions shall extend
between adjacent main vertical zone bulkheads and to the shell or exterior boundaries of the ship and shall be insulated
in accordance with the fire insulation and integrity values given in Table 22.4.
2.3 On ships designed for special purposes (automobile or railroad car ferries), where the provision of main vertical
zone bulkheads would defeat the purpose for which the ships is intended, equivalent means for controlling and limiting a
fire are to be provided and specifically approved. Service spaces and ship stores shall not be located on ro-ro decks unless
protected in accordance with the applicable regulations.
3. Bulkheads within main vertical zones
3.1 All bulkheads within accommodation and service spaces which are not required to be "A" class divisions shall
be at least "B" class or "C" class divisions as prescribed in Table 22.3. All such divisions may be faced with combustible
materials.
3.2 All corridor bulkheads where not required to be "A" class shall be "B" class divisions which shall extend from
deck to deck. Exceptions may be permitted when continuous "B" class ceilings are fitted on both sides of the bulkhead or
when the accommodations are protected by an automatic sprinkler system.
3.3 All bulkheads required to be "B" class division, except corridor bulkheads prescribed in 3.2, shall extend from
deck to deck and to the shell or other boundaries unless the continuous "B" class ceilings or linings fitted on both sides of
thebulkheadsareatleastofthesamefireresistanceasthebulkhead,inwhichcasethebulkheadmayterminateatthecontinuous
ceiling or lining.
4. Fire integrity of bulkheads and decks
4.1 In addition to complying with the specific provisions for fire integrity of bulkheads and deck mentioned elsewhere
in this Section, the minimum fire integrity of all bulkheads and decks shall be as prescribed in Tables 22.3 to 22.4.
4.2 The following requirements shall govern application of the tables :
Table 22.3 shall apply to bulkheads, separating adjacent spaces.
Table 22.4 shall apply to deck, separating adjacent spaces.
4.3 Forthepurposeofdeterminingtheappropriatefireintegritystandardstobeappliedtoboundariesbetweenadjacent
spaces, such spaces are classified according to their fire risk as shown in the following categories [1] to [11]. Where the
contents and use of a space are such that there is a doubt as to its classification for the purpose of this regulation, or where
it is possible to assign two or more classifications to a space, it shall be treated as a space within the relevant category having
the most stringent boundary requirements. Smaller, enclosed rooms within a spopenings to that space are to be considered
separate spaces. The fire integrity of the boundary bulkheads of such smaller rooms shall be as prescribed in Tables 22.3
and 22.4. The title of each category is intended to be typical rather than restrictive.
The number in parentheses preceding each category refers to the applicable column or row number in the Tables.
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Table 22.3 Fire integrity of bulkheads separating adjacent spaces
Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Control stations [1] A-03
A-0 A-60 A-0 A-15 A-60 A-15 A-60 A-60 7
A-60
Corridors [2] C5
B-05
A-01
B-05
B-05
A-60 A-0 A-0 A-15
A-04
7
A-15
Accommodation spaces [3] C5
A-01
B-05
B-05
A-60 A-0 A-0 A-15
A-04
7
A-30
A-04
Stairways [4] A-01
B-05
A-01
B-05
A-60 A-0 A-0 A-15
A-04
7
7
A-15
Service spaces (low risk) [5] C5
A-60 A-0 A-0 A-0 7
A-0
Machinery spaces of category A [6] 7
A-0 A-0 A-60 7
A-60
Other machinery spaces [7] A-02
A-0 A-0 7
A-0
Cargo spaces [8] 7
A-0 7
A-0
Service spaces (high risk) [9] A-0 7
A-30
Open decks [10] - A-0
Specialcategory spacesandro-rocargo
spaces
[11] A-0
Notes to be applied to Tables 22.3 and 22.4, as appropriate
1. For clarification as to which applies see 3 and 5
2. Wherespaces are of the same numerical category and superscript2appears,abulkheadordeckoftheratingsshowninthetablesinonly required
when the adjacent spaces are for a different purpose, e.g. in category [9]. A galley next to a galley does not require a bulkhead but a galley next
to a paint room requires an "A-0" bulkhead.
3. Bulkheads separating the wheelhouse and chartroom from each other may be "B-0" rating.
4. Indeterminingtheapplicablefireintegritystandardofaboundarybetweentwospaceswhichareprotectedbyanautomaticsprinklersystem,
the lesser of the two values given in the tables shall apply.
5. For the application of 2.1 "B-0" and "C" , where appearing in Table 22.3 shall be read as "A-0".
6. Fire insulation need not be fitted if the machinery space of category [7], in the opinion of the Administration, has little or no fire risk.
7. Where a 7 appears in the tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class
standard.
For the application of 2.1 a 7, where appearing in Table 22.4 except for categories 8 and 10, shall be read as "A-0".
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Table 22.4 Fire integrity of decks separating adjacent spaces
Space above
Space below
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Control stations [1] A-0 A-0 A-0 A-0 A-0 A-60 A-0 A-0 A-0 7
A-30
Corridors [2] A-0 7 7
A-0 7
A-60 A-0 A-0 A-0 7
A-0
Accommodation spaces [3] A-60 A-0 7
A-0 7
A-60 A-0 A-0 A-0 7
A-30
A-04
Stairways [4] A-0 A-0 A-0 7
A-0 A-60 A-0 A-0 A-0 7
A-0
Service spaces (low risk) [5] A-15 A-0 A-0 A-0 7
A-60 A-0 A-0 A-0 7
A-0
Machinery spaces of category A [6] A-60 A-60 A-60 A-60 A-60 7
A-606
A-30 A-60 7
A-60
Other machinery spaces [7] A-15 A-0 A-0 A-0 A-0 A-0 7
A-0 A-0 7
A-0
Cargo spaces [8] A-60 A-0 A-0 A-0 A-0 A-0 A-0 7
A-0 7
A-0
Service spaces
(high risk)
[9] A-60 A-30
A-04
A-30
A-04
A-30
A-04
A-0 A-60 A-0 A-0 A-0 7
A-30
Open decks [10] 7 7 7 7 7 7 7 7 7
- A-0
Special category spaces and ro-ro cargo
spaces
[11] A-60 A-15 A-30
A-04
A-15 A-0 A-30 A-0 A-0 A-30 A-0 A-0
See note under Table 22.3
[1] Control stations
Spaces containing emergency sources of power and lighting.Wheelhouseandchart-room.Spacescontainingtheship's
radio equipment. Fire control stations. Control room for propulsion machinery when located outside the propulsion
machinery space. Spaces containing centralized fire alarm equipment.
[2] Corridors
Passenger and crew corridors and lobbies.
[3] Accommodation spaces
Spaces used for public spaces, lavatories, cabins, offices, hospitals, cinemas, games and hobby rooms, barber ships,
pantries containing no cooking appliances and similar spaces.
[4] Stairways
Interior stairways, lifts, totally enclosed emergency escape trunks and escalators (other than those wholly contained
within machinery spaces) and enclosures thereto.
In this connection, a stairways which is enclosed only at one level shall be regarded as part of the space from which
it is not separated by a fire door.
[5] Service spaces (low risk)
Lockers and store-rooms not having provisions for the storage of flammable liquids and having areas less than 4 m2
and drying rooms and laundries.
[6] Machinery spaces of category A.
Spaces and trunks to such spaces which contain:
internal combustion machinery used for main propulsion; or
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internalcombustionmachineryusedforpurposesotherthanmainpropulsionwheresuchmachineryhasintheaggregate
a total power output of not less than 375 kW; or
any oil-fired boiler or oil fuel unit.
[7] Other machinery spaces
Spaces, other than machinery spaces of category A, containing propulsion machinery, boilers, oil fuel units, steam
andinternalcombustionengines,generatorsandmajorelectricalmachinery,oilfillingstations, refrigerating,stabilizing,
ventilation and air conditioning machinery, and similar spaces,and trunks to such spaces. Electrical equipment rooms
(auto-telephone exchange, air-conditioning duct spaces)
[8] Cargo spaces
All spaces used for cargo (including cargo oil tanks) and trunkways and hatchways to such spaces, other than special
category spaces.
[9] Service spaces (high risk)
Galleys, pantries containing cooking appliances, paint and lamp rooms, lockers and store-rooms having areas of 4
m2
or more, spaces for the storage of flammable liquids, saunas and workshops other than those forming part of the
machinery spaces.
[10] Open decks
Open deck spaces and enclosed promenades having little or nofire risk. Enclosed promenades shall have no significant
firerisk,meaningthatfurnishingshouldberestrictedtodeckfurniture.Inaddition,suchspacesshallbenaturallyventilated
by permanent openings. Air spaces (the space outside superstructures and deckhouses).
[11] Special category spaces and ro-ro cargo spaces
4.4 Continuous "B" class ceilings or linings, in association with the relevant decks or bulkheads, may be accepted
as contributing wholly or in part, to the required insulation and integrity of a division.
4.5 See B.4.5.
5. Protection of stairways and lifts in accommodation and service spaces.
5.1 Allstairwaysinaccommodationandservicespacesaretobeofsteelframeorotherapprovedequivalentconstruction;
they are to be arranged within enclosures formed by "A" Class divisions, with effective means of closure for all openings.
The following exceptions are admissible :
5.1.1 Astairwayconnectingonlytwodecksneednotbeenclosed,providedthattheintegrityofthepierceddeckismaintained
by suitable bulkheads or doors at one of the two decks. When a stairway is closed at one 'tweendeck space, the stairway
enclosed shall be protected in accordance with the tables for decks.
5.1.2 Stairways fitted within a closed public space need not be enclosed.
5.2 Stairway enclosures are to be directly accessible from the corridors and of sufficient area to prevent congestion,
having in mind the number of persons likely to use them in an emergency. Within the perimeter of such stairway enclosures,
onlypublicspaces,lockersofnon-combustiblematerialprovidingstorageforsafetyequipmentandopeninformationcounters
are permitted. Only public spaces, corridors, public toilets, special category spaces, other escape stairways required by
12.1.3 and external areas are permitted to have direct access to these stairway enclosures. Small corridors or lobbies used
to separate an enclosed stairway from galleys or main laundries may have direct access to the stairway provided they
have a minimum deck area of 4,5 m², a width of no less than 900 mm and contain a fire hose station.
5.3 Lift trunks shall be so fitted as to prevent the passage of smoke and flame from one ‘ween deck to another and
shall be provided with means of closing so as to permit the control of draught and smoke.
6. Openings in "A" class divisions
6.1 Where "A"class divisions are penetratedfor the passageofelectriccables, pipes, trunks,ducts, etc, or for girders,
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shall be provided, one of which may be a porthole or window of sufficient size or another means.
12.5 In special category spaces the number and disposition of the means of escape both below and above the bulkhead
deck shall be satisfactory as mentioned under 12.3.1, .2 and .3.
12.6 Two means of escape shall be provided from each machinery space. In particular, the following provisions shall
be complied with :
12.6.1 Where the space is below the bulkhead deck the two means of escape shall consist of either :
12.6.1.1 two sets of steel ladders as widely separated as possible, leading to doors in the upper part of the space similarly
separated and from which access is provided to the appropriate life boat and liferaft embarkation decks. One of these
ladders shall be located within a protected enclosure having fire integrity, including insulation values, in accordance
with the Tables 22.3 and 22.4 for a category [4] space, from the lower part of the space to a safe position outside the space.
Self-closing doors of the same fire integrity standards shall be fitted in the enclosure. The ladder shall be fixed in such a
way that heat is not transferred into the enclosure through non-insulated fixing points. The protected enclosure shall have
minimum internal dimensions of at least 800 mm × 800 mm, and shall have emergency lighting provisions.
12.6.1.2 oronesteelladderleadingtoadoorintheupperpartofthespacefromwhichaccess isprovidedtotheembarkation
deck an additionally, in the lower part of the space and in a position well separated from the ladder referred to, a steel door
capable of being operated from each side and which provides access to a safe escape route from the lower part of the space
to the embarkation deck.
12.6.2 Where the space is above the bulkhead deck, two means of escape shall be as widely separated as possible and
the doors leading from such means of escape shall be in a position from which access is provided to the appropriate lifeboat
and liferaft embarkation decks. Where such escapes require the use of ladders these shall be of steel.
12.6.3 A ship of a gross tonnage less than 1000 may be dispensed with one of the means of escape, due regard being
paid to the width and disposition of the upper part of the space; and a ship of a gross tonnage of 1000 and above, may be
dispensed with one means of escape from any such space so long as either a door or a steel ladder provides a safe escape
routetotheembarkationdeck,dueregardbeing paid to the nature and location of the space and wether persons are normally
employed in that space.
12.6.4 In the steering gear room, a second means of escape shall be provided when the emergency steering position is
located in that space unless there is direct access to the open deck.
12.6.5 Oneoftheescaperoutesfromthemachineryspaceswherethecrew is normally employed shallavoiddirectaccess
to any special category space.
12.6.6 Two means of escape shall be provided from a machinery control room within a machinery space, at least one
of which shall provide continuous fire shelter to a safe position outside the machinery space.
12.7 Additional requirements for ro-ro passenger ships
See B.12.7.
13. Fixed fire detection and fire alarm systems and automatic sprinkler, fire detection and fire alarm systems
In any ship there shall be installed throughout each separate zone, whether vertical or horizontal, in all accommodation
and service spaces and, where it is considered necessary, in control stations, except spaces which afford no substantial fire
risk (such as void spaces, sanitary spaces, etc.) either:
13.1 a fixed fire detection and fire alarm system (see also Rules for Machinery Installations, Volume III, Section
12); or
13.2 an automatic sprinkler, fire detection and fire alarm system and in addition a fixed fire detection and fire alarm
systemsoinstalledandarrangedastoprovidesmokedetectionincorridors,stairwaysandescaperouteswithinaccommodation
spaces.
14. Protection of vehicle, special category and ro-ro spaces
14.1 The subdivision of such spaces in main vertical zones would defeat their intended purpose. Therefore equivalent
protection shall be obtained in such spaces on the basis of a horizontal zone concept. A horizontal zone may include special
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category and ro-ro spaces on more than one deck provided that the total overall clear height for vehicles does not exceed
10 m, whereas the total overall clear height is the sum of distances between deck and web frames of the decks forming the
horizontal zone.
14.2 Structural protection
The boundary bulkheads and decks of special category spaces shall be insulated as required for category [11] spaces in
Tables 22.3 and 22.4, whereas the boundary bulkheads and decks of closed and open ro-ro spaces shall have fire integrity
as required for category [8] spaces in Tables 22.3 and 22.4. Indicators shall be provided on the navigating bridge which
shall indicate when any fire door leading to or from the special category space is closed.
14.3 Fixed fire-extinguishing system
14.3.1 Vehicle spaces and ro-ro spaces which are not special category spaces and are capable of being sealed from a
location outside of the cargo spaces shall be fitted with a fixed gas fire-extinguishing system of an approved type (see also
Rules for Machinery Installations, Volume.III, Section 12).
14.3.2 Ro-roandvehiclespacesnotcapableofbeingsealedandspecialcategoryspacesshallbefittedwithafixed pressure
water spraying system for manual operation of an approved type (see also Rules for Machinery Installations, Volume III,
Section 12).
14.4 Ventilation system
There shall be provided an effective power ventilation system for the special category spaces sufficient to give at least 10
air changes per hour and for closed ro-ro and vehicle spaces sufficient to give at least 6 air changes per hour. Beyond this,
ahigher air exchangerateisrequiredduringtheperiodofloadingandunloading.Thesystemforsuchspacesshallbeentirely
separated from other ventilation systems and shall be operating at all times when vehicles are in such spaces.
Ventilation ducts serving such spaces capable of being effectively sealed shall be separated for each such space. The system
shall be capable of being controlled from a position outside such spaces.
The ventilation shall be such as to prevent air stratification and the formation of air pockets.
Means shall be provided to indicate on the navigating bridge any loss or reduction of the required ventilating capacity.
Arrangements shall be provided to permit a rapid shut-down and effective closure of the ventilation system in case of fire,
taking into account the weather and sea conditions.
Ventilation ducts, including dampers, within a common horizontal zone shall be made of steel.
Ducts passing through other horizontal zones or machinery spaces shall be "A-60" class steel ducts complying with 9.11.
Permanent openings in the side plating, the ends or deckhead of the spaces shall be so situated that a fire in the cargo space
does not endanger stowage areas and embarkation stations for survival craft and accommodation spaces, service spaces
and control stations in superstructures and deckhouses above the cargo spaces.
14.5 Fire detection
Thereshallbeprovidedafixedfiredetectionandfirealarmsystemofanapprovedtype(seealsoRulesforMachineryInstallations,
Volume III, Section 12).
A sample extraction smoke detection system of an approved type (see also Rules for Machinery Installations, Volume III,
Section 12) may be accepted as equivalent, except for open ro-ro spaces, open vehicle spaces and special category spaces.
An efficient fire patrol system shall be maintained in special category spaces. In case of a continuous fire watch at all times
during the voyage, a fixed fire detection and alarm system is not required therein.
15. Special arrangements in machinery spaces of category A
15.1 The number of skylights, doors, ventilators, openings in funnels to permit exhaust ventilation and other openings
to machinery spaces shall be reduced to a minimum consistent with the needs of ventilation and the proper and safe working
of the ship.
15.2 Skylights shall be of steel and shall not contain glass panels. Suitable arrangements shall be made to permit the
release of smoke in the event of fire, from the space to be protected. The normal ventilation systems may be acceptable for
this purpose.
15.3 Means of control shall be provided for permitting the release of smoke and such controls shall be located outside
the space concernedsothat, in the event of fire, they will not becut off from the space they serve. The controlsshallbesituated
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4.4 External boundaries which are required in 1.1 to be of steel or other equivalent material may be pierced for the
fittingofwindowsandsidescutlesprovidedthatthereisnorequirementforsuchboundariestohave"A"classintegrityelsewhere
intheserequirements.Similarly,insuchboundarieswhicharenotrequiredtohave"A"classintegrity,doorsmaybeofmaterials
to meet the requirements of their application.
4.5 The following requirements shall govern application of the Tables:
Tables 22.5 and 22.6 shall apply respectively to the bulkheads and decks separating adjacent spaces.
4.6 For determining the appropriate fire integrity standards to be applied to divisions between adjacent spaces, such
spaces are classified according to their fire risk as shown in the following categories [1] to [11]. Where the contents and
use of a space are such that there is a doubt as to its classification for the purpose of this regulation, or where it is possible
to assign two or more classifications to a space, it shall be treated as a space within the relevant category having the most
stringent boundary requirements. Smaller, enclosed room within a space that have less than 30 % communicating openings
to that space are to be considered separate spaces. The fire integrity of the boundary bulkheads of such smaller rooms shall
beasprescribedinTables22.5and22.6.Thetitleofeachcategoryisintendedtobetypicalratherthanrestrictive.Thenumber
in parentheses preceding each category refers to the applicable column or row number in the tables.
Table 22.5 Fire integrity of bulkheads separating adjacent spaces
Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Control stations [1] A-05
A-0 A-60 A-0 A-15 A-60 A-15 A-60 A-60 10
A-60
Corridors [2] C B-0 B-0
A-03
B-0 A-60 A-0 A-0 A-0 10
A-30
Accommodation spaces [3] C1,2
B-0
A-03
B-0 A-60 A-0 A-0 A-0 10
A-30
Stairways [4] B-0
A-03
B-0
A-03
A-60 A-0 A-0 A-0 10
10
A-30
Service spaces (low risk) [5] C A-60 A-0 A-0 A-0 10
A-0
Machinery spaces of category A [6] 10
A-0 A-07
A-60 10
A-606
Other machinery spaces [7] A-04
A-0 A-0 10
A-0
Cargo spaces [8] 10
A-0 10
A-0
Service spaces (high risk) [9] A-04 10
A-30
Open decks [10] - A-0
Ro-ro and vehicle spaces [11] 10,8
Notes to be applied to Tables 22.5 and 22.6, as appropriate
1. No special requirements are imposed upon bulkheads in methods IIC and IIIC fire protection.
2. In case of method IIC "B" class bulkheads of "B-0" rating shall be provided between spaces or groups of spaces of 50 m2
and over
in area.
3. For clarification as to which applies, see 3 and 5.
4. Where spaces are of the same numerical category and superscript 4 appears, a bulkhead or deck of the rating shown in the Tables in only
required when the adjacent spaces are for a different purpose, e.g. in category [9]. A galley next to a galley does not require a bulkhead
but a galley next to a paint room requires an "A-0" bulkhead.
5. Bulkheads separating the wheelhouse, chartroom and radio room from each other may be "B-0" rating.
6. "A-0" rating may be used if no dangerous goods are intended to be carried or if such goods are stowed not less than 3 m horizontally
from such bulkhead.
7. For cargo spaces in which dangerous goods are intended to be carried 4.2 applies.
8. Bulkheads and decks separating ro-ro cargo spaces shall be capable of being closed reasonably gastight and such divisions shall have
"A" class integrity in so far as is reasonable and practicable.
9. Fire insulation need not be fitted if the machinery spaces in category [7], has little or no fire risk.
10. Where a 10 appears in the Tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class
standard.
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Table 22.6 Fire integrity of decks separating adjacent spaces
Space above
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Space below
Control stations [1] A-0 A-0 A-0 A-0 A-0 A-60 A-0 A-0 A-0 10
A-60
Corridors [2] A-0 10 10
A-0 10
A-60 A-0 A-0 A-0 10
A-30
Accommodation spaces [3] A-60 A-0 10
A-0 10
A-60 A-0 A-0 A-0 10
A-30
Stairways [4] A-0 A-0 A-0 10
A-0 A-60 A-0 A-0 A-0 10
A-30
Service spaces (low risk) [5] A-15 A-0 A-0 A-0 10
A-60 A-0 A-0 A-0 10
A-0
Machinery spaces of category A [6] A-60 A-60 A-60 A-60 A-60 10
A-609
A-30 A-60 10
A-60
Other machinery spaces [7] A-15 A-0 A-0 A-0 A-0 A-0 10
A-0 A-0 10
A-0
Cargo spaces [8] A-60 A-0 A-0 A-0 A-0 A-0 A-0 10
A-0 10
A-0
Service spaces (high risk) [9] A-60 A-0 A-0 A-0 A-0 A-60 A-0 A-0 A-04 10
A-30
Open decks [10] 10 10 10 10 10 10 10 10 10
- 10
Ro-ro and vehicle spaces [11] A-60 A-30 A-30 A-30 A-0 A-60 A-0 A-0 A-30 10 10, 8
See notes under Table 22.5
[1] Control stations
Spaces containing emergency sources of power and lighting. Wheelhouse and chart-room.Spacescontainingtheship's
radio equipment. Fire control stations. Control room for propulsion machinery when located outside the machinery
space. Spaces containing centralized fire alarm equipment.
[2] Corridors
Corridors and lobbies.
[3] Accommodation spaces
Spaces used for public spaces, lavatories, cabins, offices, hospitals, cinemas, games and hobby rooms, barber ships,
pantries containing no cooking appliances and similar spaces.
[4] Stairways
Interior stairways, lifts, totally enclosed emergency escape trunks and escalators (other than those wholly contained
within the machinery spaces) and enclosures thereto.
In this connection, a stairway which is enclosed only at one level shall be regarded as part of the space from which
it is not separated by a fire door.
[5] Service spaces (low risk)
Lockers and store-rooms not having provision for the storage of flammable liquids and having areas less than 4 m2
and drying rooms and laundries.
[6] Machinery spaces of category A
Spaces and trunks to such spaces which contain:
internal combustible machinery used for main propulsion; or
internalcombustiblemachineryusedforpurposesotherthanmainpropulsionwhere suchmachineryhasintheaggregate
a total power output of not less than 375 kW; or
any oil-fired boiler or oil fuel unit.
[7] Other machinery spaces
Spaces, other than machinery spaces of category A, containing propulsion machinery, boilers, oil fuel units, steam and
internal combustion engines, generators and major electrical machinery, oil filling stations, refrigerating, stabilizing,
ventilation and air conditioning machinery, and similar spaces,and trunks to such spaces. Electrical equipment rooms
(auto-telephone exchange, air-conditioning duct spaces).
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[8] Cargo spaces
All spaces used for cargo (including cargo oil tanks) and trunkways and hatchways to such spaces.
[9] Service spaces (high risk)
Galleys, pantries containing cookingappliances, saunas, paint and lamp rooms, lockers and store-rooms having areas
of4m2
ormore,spacesforthestorageofflammableliquids,andworkshopsotherthanthoseformingpartofthemachinery
spaces.
[10] Open decks
Open deck spaces and enclosed promenades having no fire risk. Enclosed promenades shall have no significant fire
risk,meaningthatfurnishingshouldberestrictedtodeckfurniture.Inaddition,suchspacesshallbenaturallyventilated
by permanent openings. Air spaces (the space outside superstructures and deckhouses).
[11] Ro-ro and vehicle spaces
5. Protection of stairways and lift trunks in accommodation spaces, service spaces and control stations
5.1 Stairwayswhichpenetrateonlyasingledeck shall be protected at least at one level by atleast"B-0"classdivisions
and self-closing doors. Lifts which penetrate only a single deck shall be surrounded by "A-0"class divisions with steel doors
at both levels. Stairways and lift trunks which penetrate more than a single deck shall be surrounded by at least "A-0" class
divisions and be protected by self-closing doors at all levels.
5.2 On ships having accommodation for 12 persons or less, where stairways penetrate more than a single deck
and where there are at least two escape routes direct to the open deck at every accommodation level, consideration may
be given reducing the "A-0" requirements of 5.1 to "B-0".
5.3 All stairways shall be of steel frame construction or of other equivalent material.
6. Openings in fire resisting divisions
6.1 Where "A" or "B" class division are penetrated for the passage of electric cables, pipes, trunks, ducts, etc. or
forgirders,beamsorotherstructuralmembers,arrangementsshallbe made to ensure thatthe fire resistanceisnotimpaired.
6.2 Except for hatches between cargo, special category, store, and baggage spaces, and between such spaces and
theweatherdecks,allopeningsshallbeprovidedwithpermanentlyattachedmeansofclosingwhichshallbeatleastaseffective
for resisting fires as the divisions in which they are fitted 30)
.
6.3 The fire resistance of doors shall be equivalent to that of the division in which they are fitted. Doors and door
frames in"A"class divisions shallbe constructedofsteel. Doors in"B"class divisions shallbenon-combustible. Doors fitted
in boundary bulkheads of machinery spaces of category A shall be reasonably gastight and self-closing. In ships constructed
according to method IC the use of combustible materials in doors separating cabins from individual interior sanitary
accommodation such as showers may be permitted.
6.4 Doorsrequiredtobe self-closing shallnotbefittedwithhold-backhooks.However,hold-backarrangementsfitted
with remote release devices of the fail-safe type may be utilized.
6.5 In corridor bulkheads ventilation openings may be permitted only in and under class B-doors of cabins and public
spaces. Ventilation openings are also permitted in B-doors leading to lavatories, offices, pantries, lockers and store rooms.
Except as permitted below, the openings shall be provided only in the lower half of a door. Where such opening is in or under
adoorthetotalnetareaofanysuchopeningoropeningsshallnotexceed0,05m².Alternatively,anon-combustibleairbalance
duct routed between the cabin and the corridor, and located below the sanitary unit is permitted where the cross-sectional
area of the duct does not exceed 0,05 m². Ventilation openings, except those under the door, shall be fitted with a grille made
of non-combustible material.
6.6 Watertight doors need not be insulated.
30)
Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67).
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11.2 Doors in escape routes shall, in general, open in-way of the direction of escape, except that
11.2.1 individual cabin doors may open into the cabins in order to avoid injury to persons in the corridor when the door
is opened, and
11.2.2 doors in vertical emergency escape trunks may open out of the trunk in order to permit the trunk to be used both
for escape and access.
11.3 Stairways and ladders shall be so arranged as to provide, from all accommodation spaces and from spaces in
which the crew is normally employed, other than machinery spaces, ready means of escape to the open deck and thence to
the lifeboats and liferafts. In particular the following general provisions shall be complied with :
11.3.1 At all levels of accommodation there shall be provided at least two widely separated means of escape from each
restricted space or group of spaces.
11.3.2 Below the lowest open deck the main means of escape shall be a stairway and the second escape may be a trunk
or stairway.
11.3.3 Above the lowest open deck the means of escape shall be stairways or doors to an open deck or a combination
thereof.
11.4 Stairways and corridors used as means of escape shall be not less than 700 mm in clear width and shall have
a handrail on one side. Stairways and corridors with a clear width of 1800 mm and above shall have handrails on both sides.
The angle of inclination of stairways shall be, in general, 45°, but not greater than 50°, and in machinery spaces and small
spaces not more than 60°. Doorways which give access to a stairway shall be of the same size as the stairway 37)
.
11.5 Dispense may be given with one of the means of escape, due regard being paid to the nature and location of spaces
and to the numbers of persons who normally might be quartered or employed there.
11.6 No dead-end corridors having a length of more than 7 m shall be accepted. A dead-end corridor is a corridor
or part of a corridor from which there is only one escape route.
11.7 If a radiotelegraph station has no direct access to the open deck, two means of access to or egress from such
stationshallbeprovided,oneofwhichmaybeaportholeorwindow of sufficient size or other means to provide an emergency
escape.
11.8 At least two means shall be provided in ro-ro cargo spaces where the crew are normally employed. The escape
routes shall provide safe escape to the lifeboat and liferaft embarkation decks and shall be located at the fore and aft ends
of the space.
11.9 TwomeansofescapeshallbeprovidedfromeachmachineryspaceofcategoryA.Inparticular,oneofthefollowing
provisions shall be complied with :
11.9.1 Two sets of steel ladders as widely separated as possible leading to doors in the upper part of the space similarly
separatedandfromwhichaccessisprovidedtotheopendeck.Oneoftheseladdersshallbelocatedwithinaprotectedenclosure
having fire integrity, including insulation values, in accordance with the Tables 22.5 and 22.6 for category [4] space from
the lower part of the space to a safe position outside the space. Self-closing fire doors having the same fire integrity shall
be fitted in the enclosure. The ladder shall be fixed in such a way that heat is not transferred into the enclosure through non-
insulated fixing points. The enclosure shall have minimum internal dimensions of at least 800 mm × 800 mm, and shall have
emergency lighting provisions; or
11.9.2 One steel ladder leading to a door in the upper part of the space from which access is provided to the open deck
and additionally, in the lower part of the space and in a position well separated from the ladder referred to, a steel door
capable of being operated from each side and which provides access to a safe escape route from the lower part of the space
to the open deck.
11.9.3 For a ship of a gross tonnage less than 1000, dispense may be given with one of the means of escape due regard
being paid to the dimension and disposition of the upper part of the space.
37)
Reference is made to the Fire Safety Systems Code adopted by IMO by Resolution MSC 98(73).
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1.4 Chemical tankers and gas carriers shall comply with the requirements of this Section, unless other and additional
safety precautions according the requirements for Ships Carrying Liquefied Gases inBulk(VolumeIX)andtherequirements
for Ships Carrying Dangerous Chemicals in Bulk (Volume X) apply.
2. Construction
2.1 Exterior boundariesofsuperstructuresanddeckhousesenclosingaccommodationandincludinganyoverhanging
decks which support such accommodation, shall be constructed of steel and insulated to "A-60" standard for the whole of
the portions which face the cargo area and on the outward sides for a distance of 3 m from the end boundary facing the cargo
area. In the case of the sides of those superstructures and deckhouses, such insulation shall be carried up to the underside
of the bridge deck.
2.2 Entrances, air inlets and openings to accommodation spaces, service spaces and control stations shall not face
the cargo area. They shall be located on the end bulkhead not facing the cargo area and/or on the outboard side of the
superstructure or deckhouse at a distance of at least 4% of the length of the ships but not less than 3 m from the end of the
superstructure or deckhouse facing the cargo area. This distance, however, need not exceed 5 m.
In this area doors to those spaces not having access to accommodation spaces, service spaces and control stations, such
as cargo control stations, provision rooms, store-rooms and engine rooms may be permitted provided that the boundaries
of the spaces are insulated to "A-60" standard. Bolted plates for the removal of machinery may be fitted within the limits
of such areas. Navigating bridge doors and wheelhouse windows may be located within this area, so long as they are so
designed that a rapid and efficient gas and vapour tightening of the navigating bridge can be ensured.
2.3 Windows and side scuttles facing the cargo area and on the sides of the superstructures and deck-houses within
the limits specified in 2.2 shall be of the fixed (non-opening) type 38)
.
Such windows and side scuttles, except wheelhouse windows, shall be constructed to "A-60" class standard and shall be
of an approved type, except the "A-0" class standard is acceptable for windows and sidescuttles outside the limits specified
in 2.1.
2.4 Skylights to cargo pump rooms shall be of steel, shall not contain any glass and shall be capable of being closed
from outside the pump room.
2.5 Furthermore the requirements of Section 24, Paragraph A.4 are to be observed.
3. Structure, bulkheads within accommodation and service spaces and details of construction
For the application of the requirements of D.2, D.3 and D.9 to tankers, only method IC as defined in D.2.1.1 shall be used.
4. Fire integrity of bulkheads and decks
4.1 In lieu of D.4 and in addition to complying with the specific provisions for fire integrity of bulkheads and decks
mentioned elsewhere in this Section the minimum fire integrity of bulkheads and decks shall be as prescribed in Tables 22.7
and 22.8.
4.2 The following requirements shall govern application of the Tables :
Tables 22.7 and 22.8 shall apply respectively to the bulkhead and deck separating adjacent spaces.
4.3 For determining the appropriate fire integrity standards to be applied to divisions between adjacent spaces, such
spaces are classified according to their fire risk as shown in categories [1] to [10] below. Where the contents and use of
a space are such that there is a doubt as to its classificationfor the purpose of this regulation, or where it is possible to assign
two or more classifications to a space, it shall be treated as a space within the relevant category having the most stringent
boundary requirements. Smaller, enclosed rooms within a space that have less than 30% communicating openings to that
spaceareconsideredseparatespaces.Thefireintegrityoftheboundarybulkheadsofsuchsmallerroomsshallbeasprescribed
in Tables 22.7 and 22.8. The title of each category is intended tobe typical rather than restrictive. The number in parentheses
preceding each category refers to the applicable column or row in the Tables.
[1] Control stations
Spaces containing emergency sources of power and lighting. Wheelhouse and chartroom. Spaces containing the ship's
38)
Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67).
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-385-320.jpg)
![F Section 22 - Structural Fire Protection on Board Seagoing Ships22-46/48
radio equipment. Fire control stations. Control room for propulsion machinery when located outside the machinery
space. Spaces containing centralized fire alarm equipment.
[2] Corridors
Corridors and lobbies.
[3] Accommodation spaces
Spaces used for public spaces, lavatories, cabins, offices, hospitals, cinemas, games and hobbies rooms, barber shops,
pantries containing no cooking appliances and similar spaces.
[4] Stairways
Interior stairways, lifts, totally enclosed emergency escape trunks and escalators (other than those wholly contained
within the machinery spaces) and enclosures thereto.
In this connection, a stairway which is enclosed only at one level shall be regarded as part of the space from which
it is not separated by a fire door.
[5] Service spaces (low risk)
Lockers and store-rooms not having provisions for the storage of flammable liquids and having areas less than 4 m2
and drying rooms and laundries.
[6] Machinery spaces of category A
Spaces and trunks to such spaces which contain:
internal combustion machinery used for main propulsion; or
internalcombustionmachineryusedforpurposesotherthanmainpropulsionwhere suchmachineryhasintheaggregate
a total power output of not less than 375 kW; or
any oil-fired boiler or oil fuel unit.
[7] Other machinery spaces
Spaces, other than machinery spaces of category A, containing propulsion machinery, boilers, oil fuel units, steam
andinternalcombustionengines,generatorsandmajorelectricalmachinery,oilfillingstations,refrigerating,stabilizing,
ventilationandair conditioningmachinery, andsimilar spaces, andtrunks tosuch spaces. Electricalequipmentrooms
(auto-telephone exchange and air-conditioning duct spaces).
[8] Cargo pump rooms
Spaces containing cargo pumps and entrances and trunks to such spaces.
[9] Service spaces (high risk)
Galleys, pantries containing cooking appliances, saunas, paint and lamp rooms, lockers and store-rooms having areas
of4m2
ormore,spacesforthestorageofflammableliquids,andworkshopsotherthanthoseformingpartofthemachinery
spaces.
[10] Open decks
Open deck spaces and enclosed promenades having little or no fire risk. Air spaces (the space outside superstructures
and deckhouses).
4.4 Continuous "B" class ceilings or linings, in association with the relevant decks or bulkheads, may be accepted
as contributing wholly or in part, to the required insulation and integrity of a division.
4.5 External boundaries which are required in D.3.1 to be of steel or other equivalent material may be pierced for
the fitting of windows and sidescuttles provided that there is not requirement for such boundaries to have "A" class integrity
elsewhere in these requirements. Similarly, in such boundaries which are not required to have "A" class integrity, doors
may be of materials to meet the requirements of their application.
4.6 Permanentapprovedgastightlightingenclosuresforilluminatingcargopumproomsmaybepermittedinbulkheads
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![Section 22 - Structural Fire Protection on Board Seagoing Ships F 22-47/48
anddecksseparatingcargopumproomsandotherspacesprovidedtheyareofadequatestrengthandtheintegrityandgastightness
of the bulkhead or deck is maintained.
4.7 Construction and arrangement of saunas.
See B.11.6.
Table 22.7 Fire integrity of bulkheads separating adjacent spaces
Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
Control stations [1] A-03
A-0 A-60 A-0 A-15 A-60 A-15 A-60 A-60 6
Corridors
[2]
C B-0 B-0
A-01
B-0 A-60 A-0 A-60 A-0 6
Accommodation spaces
[3]
C B-0
A-01
B-0 A-60 A-0 A-60 A-0 6
Stairways
[4]
B-0
A-01
B-0
A-01
A-60 A-0 A-60 A-0 6
6
Service spaces (low risk) [5] C A-60 A-0 A-60 A-0 6
Machinery spaces of category A [6] 6
A-0 A-04
A-60 6
Other machinery spaces [7] A-02
A-0 A-0 6
Cargo pump rooms [8] 6
A-60 6
Service spaces (high risk) [9] A-02 6
Open decks [10] -
Notes to be applied to Tables 22.7 and 22.8 as appropriate
1. For clarification as to which applies, see D.3 and D.5
2. Where spaces are of the same numerical category and superscript 2 appears, a bulkhead or deck of the rating shown in the Tables
in only required when the adjacent spaces are for a different purpose, e.g. in category [9]. A galley next to a galley does not require
a bulkhead but a galley next to a paint room requires an "A-0" bulkhead.
3. Bulkheads separating the wheelhouse, chartroom and radio room from each other may be "B-0" rating.
4. BulkheadsanddecksbetweencargopumproomsandmachineryspacesofcategoryAmaybepenetratedbycargopumpshaftglands
andsimilarglanded penetrations,provided thatgastightsealswith efficientlubrication orothermeansofensuring the permanence
of the gas seal are fitted in way of the bulkhead or deck.
5. Fire insulation need not be fitted if the machinery space in category [7] has little or no fire risk.
6. Where a 6 appears in the Tables, the division is required to be of steel or other equivalent material but is not required to be of "A"
class standard.
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![F Section 22 - Structural Fire Protection on Board Seagoing Ships22-48/48
Table 22.8 Fire integrity of decks separating adjacent spaces
Space above
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
Space below
Control stations [1] A-0 A-0 A-0 A-0 A-0 A-60 A-0 - A-0 6
Corridors [2] A-0 6 6
A-0 6
A-60 A-0 - A-0 6
Accommodation spaces [3] A-60 A-0 6
A-0 6
A-60 A-0 - A-0 6
Stairways [4] A-0 A-0 A-0 6
A-0 A-60 A-0 - A-0 6
Service spaces (low risk) [5] A-15 A-0 A-0 A-0 6
A-60 A-0 - A-0 6
Machinery spaces of category A [6] A-60 A-60 A-60 A-60 A-60 6
A-605
A-0 A-60 6
Other machinery spaces [7] A-15 A-0 A-0 A-0 A-0 A-0 6
A-0 A-0 6
Cargo pump rooms [8] - - - - - A-04
A-0 6
- 6
Service spaces (high risk) [9] A-60 A-0 A-0 A-0 A-0 A-60 A-0 - A-02 6
Open decks [10] 6 6 6 6 6 6 6 6 6
-
See notes under Table 22.7
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![Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings B
for Bulk Cargo and Heavy Cargo
23-3/27
When determining the load on inner bottom pi , a cargo density of not less than 1 t/m3
is to be used.
For determining scantlings of tank side slopes the load pi is not to be taken less than the load which results from an angle
of heel of 20E.
4.3.2 Where the plating has been designed according to the following formula, in connection with 9. the Notation "G"
may be entered into the Certificate behind the Character of Classification :
tG = [mm]
The thickness, however, need not exceed 30 mm.
Note
The stressing of the inner bottom plating depends mainly on the use of grabs, therefore, damage of plating cannot be
excluded, even in case of compliance with the above recommendation.
4.3.3 Sufficient continuity of strength is to be provided for between the structure of the bottom wing tanks and the
adjacent longitudinal structure.
5. Side Structures
5.1 Side longitudinals, longitudinal stiffeners, main frames
The scantlings of side longitudinals are to be determined according to Section 9, B. The longitudinal stiffeners at the lower
tank side slopes are to have the same section modulus as the side longitudinals. Their scantlings are also to be checked for
the load according to 4.3.1. For the longitudinal stiffeners of the topside tanks within the upper flange Section 9, B.1.5 is
to be observed.
5.2 Main frames and end connection
The section modulus of main frames of single side skin bulk carrier is to be increased by at least 20% above the value
required by Section 9, A.2.1.1.
The section modulus W of the frame and bracket or integral bracket, and associated shell plating, at the locations shown
in Fig. 23.1, is not to be less than twice the section modulus WF required for the frame midspan area.
The dimensions of the lower and upper brackets are not to be less than those shown in Fig. 23.2.
Structural continuity with the upper and lower end connections of side frames is to be ensured within topsides and hopper
tanks by connecting brackets as shown in Fig. 23.3.
Frames are to be fabricated symmetrical sections with integral upper and lower brackets and are to be arranged with soft
toes.
The side frame flange is to be curved (not knuckled) at the connection with the end brackets. The radius of curvature is not
to be less than r [mm], given by :
r =
where bf and tf are the flange width and thickness of the brackets, respectively [mm]. The end of the flange is to be sniped.
In ships with L < 190 m, mild steel frames may be asymmetric and fitted with separate brackets. The face plate or flange
of the bracket is to be sniped at both ends. Brackets are to be arranged with soft toes.
The web depth to thickness ratio of frames is not to exceed the following values :
= for symmetrically flanged frames
= for asymmetrically flanged frames
The outstanding flange b1 is not to exceed 10 times the flange thickness, see Fig. 23.1.
In way of the foremost hold, side frames of asymmetrical section are to be fitted with tripping brackets at every two frames
according to Section 9, A.5.5.
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![B Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings
for Bulk Cargo and Heavy Cargo
23-4/27
Where proof of fatigue strength according to Section 20 is carried out for the main frames, this proof is to be based on the
scantlings which do not include the 20% increase in section modulus.
For bulk carrier ship configurations which incorporate hopper and topside tanks the minimum thickness of frame webs in
cargo holds and ballast holds is not to be less than :
tw,min = [mm]
C = 1,15 for the frame webs in way of the foremost hold
= 1,00 for the frame webs in way of other holds
where L need not be taken greater than 200 m.
The thickness of the brackets at the lower frame ends is not to be less than the required web thickness tw of the frames or
tw,min + 2,0 mm, whichever is the greater value.
The thickness of the frame upper bracket is not to be less than the greater of tw and tw,min.
5.3 Minimum thickness of side shell plating
The thickness of side shell plating located between hopper and upper wing tanks is not to be less than tp,min [mm], given
by :
tp,min = [mm]
5.4 Weld connections of frames and end brackets
Double continuous welding is to be adopted for the connections of frames and brackets to side shell, hopper and upper wing
tank plating and web to face plates.
For this purpose, the weld throat is to be (see Fig. 23.1) :
– 0,44 · t in zone “a”
– 0,40 · t in zone “b”
where t is the plate thickness of thinner of the two connected members.
Where the hull form is such to prohibit an effective fillet weld, edge preparation of the web of frame and bracket may be
required, in order to ensure the same efficiency as the weld connection stated above.
6. Topside tanks
6.1 The plate thickness of the topside tanks is to be determined according to Section 12.
6.2 Where the transverse stiffening system is applied for the longitudinal walls of the topside tanks and for the shell
plating in way of topside tanks, the stiffeners of the longitudinal walls are to be designed according to Section.12, the
transverse frames at the shell according to Section 9, A.3.
6.3 The buckling strength of top side tank structures is to be examined in accordance with Section 3, F.
6.4 Sufficient continuity of strength is to be provided for between the structure of the topside tanks and the adjacent
longitudinal structure.
7. Transverses in the wing tanks
Transverses in the wing tanks are to be determined according to Section 12, B.3. for the load resulting from the head of water
or for the cargo load. The greater load is to be considered.
The scantlings of the transverses in the lower wing tanks are also to be examined for the loads according to 4.3.1.
8. Cargo hold bulkheads
The following requirement apply to cargo hold bulkheads on the basis of the loading conditions according to Section 5,
A.4.
For vertically corrugated transverse cargo hold bulkheads on ships according to Section 5, G. the requirements of E. apply
in addition, where the strength in the hold flooded condition has to be ensured.
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![C, D Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings
for Bulk Cargo and Heavy Cargo
23-8/27
with the ore cargo holds fitted between them, a double bottom through out the cargo length area and intended primary to
carry ore cargoes in the centre hold only.
1.2 Ships built in accordance with the following requirements will get the Notation "ORE CARRIER" affixed to
their Character of Classification. Entries will be made into the Certificate as to whether specified cargo holds may be empty
in case of alternating loading. Additional indications of the types of cargo for which the ship is strengthened may be entered
into the Certificate.
1.3 For ships subject to the provisions of this paragraph the requirements of B. are applicable unless otherwise
mentioned in this sub-section.
1.4 For ore carriers carrying also oil in bulk also Section 24, G. applies.
1.5 Where reduced freeboards according to ICLL shall be assigned, the respective requirements of the ICLL are
to be observed.
2. Double bottom
2.1 Forachieving good stability criteria in the loaded condition the double bottombetween the longitudinal bulkheads
should be as high as possible.
2.2 The strength of the double bottom structure is to comply with the requirements given in B.4.
3. Transverse and longitudinal bulkheads
3.1 The spacing of transverse bulkheads in the side tanks which are to be used as ballast tanks is to be determined
according to Section 24, as for tankers. The spacing of transverse bulkheads in way of the cargo hold is to be determined
according to Section 11.
3.2 The scantlings of cargo hold bulkheads exposed to the load of the ore cargo are to be determined according to
B.8. The scantlings of the side longitudinal bulkheads are to be at least equal to those required for tankers.
D. Allowable hold loading, considering flooding
1. General
These requirements apply to all bulk carriers, defined in Section 5, G.
The loading in each hold is not to exceed the allowable loading according to 4. and shall not exceed the design hold loading
in intact condition.
2. Load model
2.1 General
The loads to be considered as acting on the double bottom are those given by the external sea pressures and the combination
of the cargo loads with those induced by the flooding of the hold to which the double bottom belongs to.
The most severe combinations of cargo induced loads and flooding loads are to be used, depending on the loading conditions
included in the loading manual:
– homogeneous loading conditions
– non-homogeneous loading conditions
– packed cargo conditions (such as steel mill products) For each loading condition, the maximum bulk cargo
density to be carried is to be considered in calculating the allowable hold loading limit.
2.2 Inner bottom flooding head
The flooding head hf (see Fig. 23.4) is the distance [m], measured vertically with the ship in the upright position, from the
inner bottom to a level located at a distance df [m], from the baseline :
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-396-320.jpg)
![Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings D
for Bulk Cargo and Heavy Cargo
23-9/27
df is in general :
– H for the foremost hold
– 0,9 @ H for the other holds
For ships less than 50.000 tdw with Type B freeboard, df is :
– 0,95 @ H for the foremost hold
– 0,85 @ H for the other holds
3. Shear capacity of the double bottom
The shear capacity C of the double bottom is defined as the sum of the shear strength at each end of :
– all floors adjacent to both hoppers, less one half of the strength of the two floors adjacent to each stool, or
transverse bulkhead if no stool is fitted, see Fig. 23.5
– all double bottom girders adjacent to both stools, or transverse bulkheads if no stool is fitted
Where in the end holds, girders or floors run out and are not directly attached to the boundary stool or hopper girder, their
strength is to be evaluated for the one end only.
The floors and girders to be considered are those inside the hold boundaries formed by the hoppers and stools (or transverse
bulkheads if no stool is fitted). The hopper side girders and the floors directly below the connection of the bulkhead stools
(or transverse bulkheads if no stool is fitted) to the inner bottom are not to be included.
When the geometry and/or the structural arrangement of the double bottom are such to make the above assumptions
inadequate, the shear capacity C of double bottom is to be calculated by direct calculations.
In calculating the shear strength, the net thickness of floors and girders is to be used. The net thickness tnet [mm] is given
by:
tnet = t - 2,5 [mm]
t = thickness [mm], of floors and girders
Fig. 23.4 Flooding head hf of the inner bottom
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![D Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings
for Bulk Cargo and Heavy Cargo
23-10/27
Fig. 23.5 Girders and floors in the double bottom
3.1 Floor shear strength
The floor shear strength in way of the floor panel adjacent to hoppers Sf1 [kN], and the floor shear strength in way of the
openings in the outmost bay (i.e. that bay which is adjacent to the hopper) Sf2 [kN], are given by the following expressions:
=
=
Af = sectional area [mm2
], of the floor panel adjacent to hoppers
Af,h = net sectional area [mm2
], of the floor panel in way of the openings in the outmost bay (i.e. that bay which
is adjacent to the hopper)
ta = allowable shear stress [N/mm2
], to be taken equal to the lesser of
= and
For floors adjacent to the stools or transverse bulkheads, as identified in 3., Ja may be taken as
ReH = minimum upper yield stress [N/mm2
], of the hull structural steel
a = spacing of stiffening members [mm], of panel under consideration
01 = 1,10
02 = 1,20
= 1,10, where appropriate reinforcements are fitted
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![Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings D
for Bulk Cargo and Heavy Cargo
23-11/27
3.2 Girder shear strength
The girder shear strength in way of the girder panel adjacent to stools (or transverse bulkheads, if no stool is fitted) Sg1
[kN], and the girder shear strength in way of the largest opening in the outmost bay (i.e. that bay which is closer to stool,
or transverse bulkhead, if no stool is fitted) Sg2 [kN], are given by
=
=
Ag = minimum sectional area [mm2
], of the girder panel adjacent to stools (or transverse bulkheads, if no stool
is fitted)
Ag,h = net sectional area [mm2
], of the girder panel in way of the largest opening in the outmost bay (i.e. that bay
which is closer to stool, or transverse bulkhead, if no stool is fitted)
Ja = allowable shear stress [N/mm2
], as given in 3.1
01 = 1,10
02 = 1,20
= 1,10, where appropriate reinforcements are fitted
4. Allowable hold loading
Calculating the allowable hold loading HL [t], the following condition are to be complied with :
HL = the lesser of HL1 and HL2
HL1 =
HL2 = HLint
HLint = max. perm. hold loading for intact condition
F = 1,10 in general
= 1,05 for steel mill products
Dc = cargo density [t/m3
], for bulk cargoes see 2.1;
for steel products, Dc is to be taken as the density of steel
V = volume [m3
], occupied by cargo assumed flattened at a level h1
h1 =
For bulk cargoes, X is the lesser of X1 and X2 given by:
X1 =
X2 = Z + D · g · (E - hf · perm)
perm = cargo permeability, (i.e. the ratio between the voids within the cargo mass and the volume occupied
by the cargo); need not be taken greater than 0,3.
For steel products, X may be taken as X1 using a value for perm according to the type of products (pipes, flat bars, coils etc.)
harmonized with BKI.
D = 1,025 [t/m3
], sea water density
g = 9,81 [m/s2
], gravitational acceleration
E = (nominal ship) immersion [m] for flooded hold condition = df – 0,1 H
Z = the lesser of Z1 and Z2:
Z1 = [kN/m2
]
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![D, E Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings
for Bulk Cargo and Heavy Cargo
23-12/27
Z1 =
Z2 =
Ch = shear capacity of the double bottom [kN], as defined in 3., considering, for each floor, the lesser of the shear
strengths Sf1 and Sf2 (see 3.1) and, for each girder, the lesser of the shear strengths Sg1 and Sg2 (see 3.2)
Ce = shear capacity of the double bottom [kN], as defined in 3., considering, for each floor, the shear strength Sf1 (see
3.1) and, for each girder, the lesser of the shear strengths Sg1 and Sg2 (see 3.2)
= [m2
]
= [m2
]
n = number of floors between stools (or transverse bulkheads, if no stool is fitted)
Si = spacing of ith - floor [m]
BDB,i = BDB – aR for floors whose shear strength is given by Sf1, see 3.1
= BDB,h for floors whose shear strength is given by Sf2, see 3.1
BDB = breadth of double bottom [m] between hoppers, see Fig. 23.6
BDB,h = distance [m] between the two considered openings, see Fig. 23.6
aR = spacing [m], of double bottom longitudinals adjacent to hoppers.
Fig. 23.6 Effective distance BDB and BDB,h for the calculation of shear capacity
E. Evaluation of Scantlings of Corrugated Transverse Watertight Bulkheads in Bulk Carriers Considering
Hold Flooding
1. Application and definitions
These requirements apply to all bulk carriers with L > 150 m, intended for the carriage of solid bulk cargoes having bulk
density of 1,0 [t/m3
], or above, with vertically corrugated transverse watertight bulkheads.
The net thickness tnet is the thickness obtained by applying the strength criteria given in 4.
The required thickness is obtained by adding the corrosion addition tK, given in 6., to the net thickness tnet
In this requirement, homogeneous loading condition means a loading condition in which the ratio between the highest and
the lowest filling ratio, evaluated for each hold, does not exceed 1,20, to be corrected for different cargo densities
2. Load model
2.1 General
The loads to be considered as acting on the bulkheads are those given by the combination of the cargo loads with those
BKI - Rules for Hull - 2014](https://image.slidesharecdn.com/rulesforhull2014-151023210949-lva1-app6891/85/Rules-for-hull-2014-400-320.jpg)
![Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings E
for Bulk Cargo and Heavy Cargo
23-13/27
induced by the flooding of one hold adjacent to the bulkhead under examination. In any case, the pressure due to the flooding
water alone is to be considered.
The most severe combinations of cargo induced loads and flooding loads are to be used for the check of the scantlings
of each bulkhead, depending on the loading conditions included in the loading manual :
– homogeneous loading conditions
– non-homogeneous loading conditions
considering the individual flooding of both loaded and empty holds.
The specified design load limits for the cargo holds are to be represented by loading conditions defined in the loading
manual.
Non-homogeneous part loading conditions associated with multiport loading and unloading operations for homogeneous
loading conditions need not to be considered according to these requirements.
Holds carrying packed cargoes (e.g. steel products) are to be considered as empty holds for this application.
Unless the ship is intended to carry, in nonhomogeneous conditions, only iron ore or cargo having bulk density equal to or
greater than 1,78 [t/m3
], the maximum mass of cargo which may be carried in the hold shall also be considered to fill that
hold up to the upper deck level at centre line.
2.2 Bulkhead corrugation flooding head
The flooding head hf (see Fig. 23.7) is the distance [m], measured vertically with the ship in the upright position, from the
calculation point to a level located at a distance df [m], from the baseline.
df is in general :
– H for the aft transverse corrugated bulkhead of the foremost hold
– 0,9 @ H for the other bulkheads
Where the ship is to carry cargoes having bulk density less than 1,78 t/m3
in non-homogeneous loading conditions, the
following values can be assumed for df :
– 0,95 @ H for the aft transverse corrugated bulkhead of the foremost hold
– 0,85 @ H for the other bulkheads
For ships less than 50.000 tdw with Type B freeboard df is :
– 0,95 @ H for the aft transverse corrugated bulkhead of the foremost hold
– 0,85 @ H for the other bulkheads
Where the ship is to carry cargoes having bulk density less than 1,78 [t/m3
] in non-homogeneous loading conditions, the
following values can be assumed :
– 0,9 @ H for the aft transverse corrugated bulkhead of the foremost hold
– 0,8 @ H for the other bulkheads.
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![E Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings
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Fig. 23.7 Flooding head hf of a corrugated bulkhead
2.3 Pressure in the non-flooded bulk cargo loaded holds
At each point of the bulkhead, in way of length R according to Fig. 23.8 and Fig. 23.9 the pressure pc [kN/m2
], is given by:
pc = Dc · g · h1 · n
Dc = bulk cargo density [t/m3
]
g = 9,81 [m/s2
], gravitational acceleration
h1 = vertical distance [m], from the calculation point to the horizontal plane corresponding to the level height
of the cargo (see Fig. 23.7), located at a distance d1 [m], from the baseline
n =
( = angle of repose of the cargo, that may generally be taken as 35° for iron ore and 25° for cement.
The force Fc [kN], acting on a corrugation is given by :
=
e1 = spacing of corrugations [m], see Fig. 23.8
hLS = mean height of the lower stool [m], from the inner bottom
hDB = height of the double bottom [m]
2.4 Pressure in the flooded holds
2.4.1 Bulk cargo holds
Two cases are to be considered, depending on the values of d1 and df.
a) df > d1
At each point of the bulkhead located at a distance between d1 and df from the baseline, the pressure pc,f [kN/m2
], is given
by :
pc,f = D · g · hf
D = 1,025 [t/m3
], sea water density
At each point of the bulkhead located at a distance lower than d1 from the baseline, the pressure pc,f [kN/m2
], is given by:
pc,f = D · g · hf + [Dc - D (1 - perm)] g · h1 · n
perm = permeability of cargo, to be taken as 0,3 for ore (corresponding bulk cargo density for iron ore may
generally be taken as 3,0 [t/m3
]), coal cargoes and for cement (corresponding bulk cargo density for cement
may generally be taken as 1,3 [t/m3
])
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The force Fc,f [kN], acting on a corrugation is given by :
=
pc,f,le = pressure [kN/m2
], at the lower end of thecorrugation
b) df < d1
At each point of the bulkhead located at a distance between df and d1 from the baseline, the pressure pc,f [kN/m2
], is given
by :
pc,f = Dc · g · h1 · n
At each point of the bulkhead located at a distance lower than df from the baseline, the pressure pc,f [kN/m2
], is given by:
pc,f = D · g · hf + [Dc · h1 - D (1 - perm) · hf ] g · n
The force Fc,f [kN], acting on a corrugation is given by :
=
2.4.2 Pressure in empty holds due to flooding water alone
At each point of the bulkhead, the hydrostatic pressure pf induced by the flooding head hf is to be considered.
The force Ff [kN], acting on a corrugation is given by :
Ff =
2.5 Resultant pressure and force
2.5.1 Homogeneous loading conditions At each point of the bulkhead structures, the resultant pressure p [kN/m2
], to
be considered for the scantlings of the bulkhead is given by :
p = pc,f - 0,8 · pc
The resultant force F [kN], acting on a corrugation is given by :
F = Fc,f - 0,8 · Fc
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2.5.2 Non homogeneous loading conditions
At each point of the bulkhead structures, the resultant pressure p [kN/m2
], to be considered for the scantlings of the bulkhead
is given by :
p = pc,f
The resultant force F [kN], acting on a corrugation is given by :
F = Fc,f
3. Bending moment and shear force in the bulkhead corrugations
The bending moment M and the shear force Q in the bulkhead corrugations are obtained using the formulae given in 3.1
and 3.2. The M and Q values are to be used for the checks in 4.2.
3.1 Bending moment
The design bending moment M [kN • m], for the bulkhead corrugations is given by :
M =
F = resultant force [kN], as given in 2.5
R = span of the corrugation [m], to be taken according to Fig. 23.8 and 23.9
3.2 Shear force
The shear force Q [kN], at the lower end of the bulkhead corrugations is given by :
Q = 0,8 · F
F = as given in 2.5
4. Strength criteria
4.1 General
The following criteria are applicable to transverse bulkheads with vertical corrugations, see Fig. 23.8. For ships of 190 m
of length and above, these bulkheads are to be fitted with a lower stool, and generally with an upper stool below deck. For
smaller ships, corrugations may extend from inner bottom to deck. However, if any stools are fitted, they are to comply with
the requirements in 4.1.1 and 4.1.2. See also B.8.4.
The corrugation angle k shown in Fig. 23.8 is not to be less than 55°.
Requirements for local net plate thickness are given in 4.7.
In addition, the criteria as given in 4.2 and 4.5 are to be complied with.
The thicknesses of the lower part of corrugations considered in the application of 4.2 and 4.3 are to be maintained for a
distance from the inner bottom (if no lower stool is fitted) or the top of the lower stool not less than 0,15 @ R.
The thicknesses of the middle part of corrugations as considered in the application of 4.2 and 4.4 are to be maintained to
a distance from the deck (if no upper stool is fitted) or the bottom of the upper stool not greater than 0,3 @ R.
The section modulus of the corrugation in the remaining upper part of the bulkhead is not to be less than 75% of that
required for the middle part, corrected for different yield stresses.
4.1.1 Lower stool
The height of the lower stool is generally to be not less than 3 times the depth of the corrugations. The thickness and material
of the stool top plate is not to be less than those required for the bulkhead plating above. The thickness and material of the
upper portion of vertical or sloping stool side plating within the depth equal to the corrugation flange width from the stool
top is not to be less than the required flange plate thickness and material to meet the bulkhead stiffness requirement at lower
end of corrugation. The thickness of the stool side plating and the section modulus of the stool side stiffeners is not to be
less than those required according to Section 11, B. on the basis of the load model in 2. The ends of stool side vertical
stiffeners are to be attached to brackets at the upper and lower ends of the stool.
The distance d from the edge of the stool top plate to the surface of the corrugation flange is to be not less than the
corrugation flange plate thickness, measured from the intersection of the outer edge of corrugation flanges and the centre
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line of the stool top plate, see Fig. 23.12. The stool bottom is to be installed in line with double bottom floors and is to have
a width not less than 2,5 times the mean depth of the corrugation. The stool is to be fitted with diaphragms in line with the
longitudinal double bottomgirders for effective support of thecorrugated bulkhead. Scallops in the brackets and diaphragms
in way of the connections to the stool top plate are to be avoided.
Where corrugations are cut at the lower stool, corrugated bulkhead plating is to be connected to the stool top plate by full
penetration welds. The stool side plating is to be connected to the stool top plate and the inner bottom plating by either full
penetration or deep penetration welds, see Fig. 23.13. The supporting floors are to be connected to the inner bottom by either
full penetration or deep penetration welds, see Fig. 23.13.
4.1.2 Upper stool
The upper stool, where fitted, is to have a height generally between 2 and 3 times the depth of corrugations. Rectangular
stools are to have a height generally equal to 2 times the depth of corrugations, measured from the deck level and at hatch
side girder. The upper stool is to be properly supported by girders or deep brackets between the adjacent hatch-end beams.
The width of the stool bottom plate is generally to be the same as that of the lower stool top plate. The stool top of non
rectangular stools is to have a width not less then 2 times the depth of corrugations. The thickness and material of the stool
bottom plate are to be the same as those of the bulkhead plating below. The thickness of the lower portion of stool side
plating is not to be less than 80 % of that required for the upper part of the bulkhead plating where the same material is used.
The thickness of the stool side plating and the section modulus of the stool side stiffeners is not to be less than required
according to Section 11, B. on the basis of the load model in 2. The ends of stool side stiffeners are to be attached to brackets
at the upper and lower ends of the stool. Diaphragms are to be fitted inside the stool in line with and effectively attached
to longitudinal deck girders extending to the hatch end coaming girders for effective support of the corrugated bulkhead.
Scallops in the brackets and diaphragms in way of the connection to the stool bottom plate are to be avoided.
4.1.3 Alignment
At deck, if no stool is fitted, two transverse reinforced beams are to be fitted in line with the corrugation flanges.
At bottom, if no stool is fitted, the corrugation flanges are to be in line with the supporting floors. Corrugated bulkhead
plating is to be connected to the inner bottom plating by full penetration welds. The plating of supporting floors is to be
connected to the inner bottomby either full penetration or deep penetration welds, see Fig. 23.13. The thickness and material
properties of the supporting floors are to be at least equal to those provided for the corrugation flanges.
Moreover, the cut-outs for connections of the inner bottom longitudinals to double bottom floors are to be closed by collar
plates. The supporting floors are to be connected to each other by suitably designed shear plates.
Stool side plating is to align with the corrugation flanges and stool side vertical stiffeners and their brackets in lower stool
are to align with the inner bottom longitudinals to provide appropriate load transmission between these stiffening members.
Stool side plating is not to be knuckled anywhere between the inner bottom plating and the stool top.
4.2 Bending capacity and shear stress t
The bending capacity is to comply with the following relationship :
M = bending moment [kN q m], as given in 3.1
Wle = section modulus of one half pitch corrugation [cm3
], at the lower end of corrugations, to be calculated
according to 4.3
Wm = section modulus of one half pitch corrugation [cm3
], at the mid-span of corrugations, to be calculated
according to 4.4
Fa,le = allowable stress [N/mm2
], as given in 4.5, for the lower end of corrugations
Fa,m = allowable stress [N/mm2
], as given in 4.5, for the mid-span of corrugations
In no case is Wm to be taken greater than the lesser of 1,15 q Wle and 1,15 q W’le for calculation of the bending capacity,
W’le being defined below.
In case shedders plates are fitted which :
– are not knuckled
– are welded to the corrugations and the top of the lower stool by one side penetration welds or equivalent
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– are fitted with a minimum slope of 45° and their lower edge is in line with the stool side plating
– have thicknesses not less than 75 % of that provided by the corrugation flange
– and material properties at least equal to those provided by the flanges
or gusset plates are fitted which:
– are in combination with shedder plates having thickness, material properties and welded connections in
accordance with the above requirements
– have a height not less than half of the flange width
– are fitted in line with the stool side plating
– are generally welded to the top of the lower stool by full penetration welds, and to the corrugations and shedder
plates by one side penetration welds or equivalent
– have thickness and material properties at least equal to those provided for the flanges
the section modulus Wle [cm3
], is to be taken not larger than the value W’le [cm3
], given by :
W’le =
Wg = section modulus of one half pitch corrugation [cm3
], of the corrugations calculated, according to 4.4,
in way of the upper end of shedder or gusset plates, as applicable
Q = shear force [kN], as given in 3.2
hg = height [m], of shedders or gusset plates, as applicable (see Fig. 23.10 and 23.11)
e1 = as given in 2.3
pg = resultant pressure [kN/m2
], as defined in 2.5, calculated in way of the middle of the shedders or gusset
plates, as applicable
Fa = allowable stress [N/mm2
], as given in 4.5
Stresses t are obtained by dividing the shear force Q by the shear area. The shear area is to be reduced in order to account
for possible non-perpendicularity between the corrugation webs and flanges. In general, the reduced shear area may be
obtained by multiplying the web sectional area by (sin k), k being the angle between the web and the flange (see Fig. 23.8).
When calculating the section modulus and the shear area, the net plate thicknesses are to be used.
The section modulus of corrugations are to be calculated on the basis of the following requirements given in 4.3 and 4.4.
4.3 Section modulus at the lower end of corrugations
The section modulus is to be calculated with the compression flange having an effective flange width, bef , not larger than
as given in 4.6.1.
If the corrugation webs are not supported by local brackets below the stool top (or below the inner bottom) in the lower part,
the section modulus of the corrugations is to be calculated considering the corrugation webs 30 % effective.
a) Provided that effective shedder plates, as defined in 4.2, are fitted (see Fig. 23.10), when calculating the section
modulus of corrugations at the lower end (cross-section 1 in Fig. 23.10), the area of flange plates [cm2
], may be
increased by
)Af = [cm2
]
(not to be taken greater than 2,5q b q tf)
b = width [m], of the corrugation flange, see Fig. 23.8
tsh = net shedder plate thickness [mm]
tf = net flange thickness [mm]
b) Provided that effective gusset plates, as defined in 4.2, are fitted (see Fig. 23.11), when calculating the section modulus
of corrugations at the lower end (cross-section 1 in Fig. 23.11), the area of flange plates [cm2
], may be increased by
)Af = [cm2
]
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hg = height of gusset plate [m], see Fig. 23.11, not to be taken greater than :
hg = [m]
agu = width of the gusset plates [m]
= 2 q e1 – b [m]
tf = net flange thickness [mm], based on the as built condition
c) If the corrugation webs are welded to a sloping stool top plate which has an angle not less than 45° with the horizontal
plane, the section modulus of the corrugations may be calculated considering the corrugation webs fully effective.
In case effective gusset plates are fitted, when calculating the section modulus of corrugations the area of flange plates may
be increased as specified in b) above. No credit can be given to shedder plates only.
For angles less than 45°, the effectiveness of the web may be obtained by linear interpolation between 30% for 0° and 100%
for 45°.
Fig. 23.10 Shedder plates
Fig. 23.11 Gusset plates and shedder plates
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4.4 Section modulus of corrugations at cross-sections other than the lower end
The section modulus is to be calculated with the corrugation webs considered effective and the compression flange having
an effective flange width, bef, not larger than as given in 4.6.1.
4.5 Allowable stress check
The normal and shear stresses s and t are not to exceed the allowable values sa and ta [N/mm2
], given by :
Fa = ReH
Ja = 0,5 · ReH
ReH = the minimum upper yield stress [N/mm2
], of the hull structural steel
4.6 Effective compression flange width and shear buckling check
4.6.1 Effective width of the compression flange of corrugations
The effective width bef, in m, of the corrugation flange is given by :
bef = Ce q b
where:
Ce = for $ > 1.25
Ce = 1.0 for $ < 1.25
$ =
tf = net flange thickness, in mm
b = width, in m, of the corrugation flange (see Fig. 23.8)
ReH = minimum upper yield stress, in N/mm2
, of the material
E = modulus of elasticity of the material, in N/mm2
, to be assumed equal to 2,06 × 105
for steel
4.6.2 Shear buckling
The buckling check for the web plates at the corrugation ends is to be performed according to Section 3, F. The buckling
factor is to be taken as follows :
K =
The shear stress t has to be taken according to 4.2 and the safety factor S is 1,05.
4.7 Local net plate thickness
The bulkhead local net plate thickness tnet [mm], is given by :
=
Fw = plate width [m], to be taken equal to the width of the corrugation flange or web, whichever is the greater,
see Fig. 23.8
p = resultant pressure [kN/m2
], as defined in 2.5, at the bottom of each strake of plating; in all cases, the net
thickness of the lowest strake is to be determined using the resultant pressure at the top of the lower stool,
or at the inner bottom, if no lower stool is fitted or at the top of shedders, if shedder or gusset/shedder plates
are fitted
For built-up corrugation bulkheads, when the thicknesses of the flange and web are different, the net thickness of the
narrower plating is to be not less than tnet,n [mm], given by :
=
an = the width [m], of the narrower plating, see Fig. 23.8
The net thickness of the wider plating [mm], is not to be taken less than the maximum of the following values tw1 and tw2:
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Rules for hull 2014
- 1. RULES FOR THE CLASSIFICATION AND CONSTRUCTION PART 1. SEAGOING SHIPS VOLUME II RULES FOR HULL 2014 EDITION BIRO KLASIFIKASI INDONESIA
- 3. RULES FOR THE CLASSIFICATION AND CONSTRUCTION PART 1. SEAGOING SHIPS VOLUME II RULES FOR HULL 2014 EDITION Biro Klasifikasi Indonesia Jl. Yos Sudarso No. 38-40, Tanjung Priok Jakarta 14320 www.klasifikasiindonesia.com rules@klasifikasiindonesia.com Copyright © 2014 Reproduction in whole or in part by any means, is subject to the permission in writing by Biro Klasifikasi Indonesia Head Office
- 4. The following Guidelines come into force on 1st January 2014 Reproduction in whole or in part by any means, is subject to the permission in writing by Biro Klasifikasi Indonesia Head Office Published by: Biro Klasifikasi Indonesia
- 5. Foreword iii Foreword Rules for Hull Volume II 2014 Edition amends Rules for Hull Volume II Edition 2013. Reference source of the rules are derived from IACS Unified Requirements and inputs from BKI Branch Offices and Technical Division BKI Head Office. The general description about this rules in every section describe below: Section 1 General Definition Section 2 Material Section 3 Design Principles Section 4 Design Load Section 5 Longitudinal Strength Section 6-14 Scantling Calculation Section 15 Strengthening for Navigation in Ice Section 16 Superstructure and Deckhouse Section 17 Hatchways Section 18 Equipment Section 19 Welded Joints Section 20 Fatigue Strength Section 21 Hull Outfit Section 22 Structural Fire Protection on Board Seagoing Ships Section 23-34 Special Requirement for Ship Type (Bulk Carriers, Ore Carriers, Heavy Cargo Ships, Oil Tankers, Ships Carrying Dangerous Chemical in Bulk, Ships Carrying Liquefied Gases in Bulk, Tugs, Fishing Vessels, Passenger Ships, Ships for Sheltered Shallow Water Services, Barges, Pontoons, Dredgers, Special Rules Floating Docks, and Supply Vessels) Section 35 Strengthening Against Collision Section 36 Subdivision and Stability of Cargo Ships and Passanger Ships Section 37 Special Requirement for In-Water Surveys Section 38 Corrosion Protection BKI - Rules for Hull - 2014
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- 7. Table of Contents v Table of Contents Page Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v Rules Amendment Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxv Section 1 - General, Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1/10 A. Validity, Equivalence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1/10 B. Restricted Service Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2/10 C. Ships for Special Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2/10 D. Accessibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2/10 E. Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2/10 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2/10 2. Ships with proven damage stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2/10 3. Anti-heeling devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3/10 F. Vibrations and Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3/10 1. Mechanical vibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3/10 2. Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3/10 G. Documents for Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4/10 H. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6/10 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6/10 2. Principal dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6/10 J. International Conventions and Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7/10 K. Rounding-off Tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8/10 L. Regulations of National Administrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8/10 M. Computer Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8/10 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8/10 2. General Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8/10 N. Workmanship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9/10 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9/10 1.l Requirements to be complied with by the manufacturer . . . . . . . . . . . . . . . . . . . . . . . . . 1-9/10 1.2 Quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9/10 2. Structural details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9/10 2.1 Details in manufacturing documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9/10 2.2 Cut-outs, plate edges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9/10 2.3 Cold forming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10/10 2.4 Assembly, alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10/10 3. Corrosion protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10/10 Section 2 - Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1/10 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1/10 B. Hull Structural Steel for Plates and Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1/10 1. Normal strength hull structural steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1/10 2. Higher strength hull structural steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1/10 3. Material selection for the hull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2/10 4. Structural members which are stressed in direction of their thickness . . . . . . . . . . . . . . . . . . . 2-7/10 C. Forged Steel and Cast Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7/10 D. Aluminium Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7/10 E. Austenitic Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8/10 Section 3 - Design Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1/24 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1/24 1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1/24 2. Permissible stresses and required sectional properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1/24 3. Plate panels subjected to lateral pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1/24 4. Fatigue strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2/24 B. Upper and Lower Hull Flange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2/24 C. Unsupported Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2/24 BKI - Rules for Hull - 2014
- 8. Table of Contentsvi Page D. End Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3/24 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3/24 2. Brackets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3/24 3. Sniped ends of stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4/24 4. Corrugated bulkhead elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4/24 E. Effective Breadth of Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4/24 1. Frames and stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4/24 2. Girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4/24 3. Cantilevers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5/24 F. Proof of Buckling Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5/24 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5/24 2. Proof of single plate fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7/24 3. Proof of partial and total fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12/24 3.1 Longitudinal and transverse stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12/24 3.2 Lateral buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12/24 3.3 Torsional buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15/24 G. Rigidity of Transverses and Girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17/24 H. Structural Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17/24 1. Longitudinal members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17/24 2. Transverses and girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17/24 3. Knuckles (general) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19/24 J. Evaluation of Notch Stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20/24 K. Corrosion Additions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22/24 L. Additional Stresses in Asymmetric Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23/24 1. Additional stresses for fatique strength analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23/24 2. Correction of section modulus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23/24 Section 4 - Design Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1/10 A. General, Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1/10 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1/10 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1/10 2.1 Load centre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1/10 2.2 Definition of symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1/10 B. External Sea Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2/10 1. Load on weather decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2/10 2. Load on ship's sides and of bow and stern structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3/10 2.1 Load on ship's sides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3/10 2.2 Load on bow structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3/10 2.3 Load on stern structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4/10 3. Load on the ship's bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4/10 4. Design bottom slamming pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4/10 5. Load on decks of superstructures and deckhouses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5/10 C. Cargo Loads, Load on Accommodation Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6/10 1. Load on cargo decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6/10 2. Load on inner bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6/10 3. Loads on accommodation and machinery decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7/10 D. Load on Tank Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7/10 1. Design pressure for filled tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7/10 2. Design pressure for partially filled tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8/10 E. Design Values of Acceleration Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8/10 1. Acceleration components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8/10 2. Combined acceleration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9/10 Section 5 - Longitudinal Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1/27 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1/27 1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1/27 2. Calculation Particulars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1/27 3. Assumptions for calculation, loading conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1/27 4. Loading guidance information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1/27 4.1 General, definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1/27 4.2 Conditions of approval of loading manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2/27 BKI - Rules for Hull - 2014
- 9. Table of Contents vii Page 4.3 Conditions of approval of loading instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2/27 4.4 Design cargo and ballast loading conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3/27 4.5 Approval procedures of loading instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5/27 4.6 Class maintenance of loading guidance information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5/27 5. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5/27 B. Loads on the Ship’s Hull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6/27 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6/27 2. Still Water Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7/27 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7/27 2.2 Guidance values for containerships with irregular loading . . . . . . . . . . . . . . . . . . . . . . . 5-7/27 3. Wave induced loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8/27 3.1 Vertical wave bending moments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8/27 3.2 Vertical wave shear forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9/27 3.3 Horizontal bending moments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10/27 3.4 Horizontal shear forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10/27 3.5 Torsional moments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10/27 C. Section Moduli, Moments of Inertia, Shear and Buckling Strength . . . . . . . . . . . . . . . . . . . . . . . . . 5-11/27 1. Section moduli as a function of the longitudinal bending moments . . . . . . . . . . . . . . . . . . . . 5-11/27 2. Minimum midship section modulus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12/27 3. Midship section moment of inertia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12/27 4. Calculation of section moduli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12/27 5. Ships with multi-hatchways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13/27 6. Shear strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14/27 7. Proof of buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14/27 8. Ultimate load calculation of the ship's transverse sections . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14/27 D. Design Stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19/27 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19/27 1.1 Buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19/27 1.2 Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20/27 1.3 Structural design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20/27 2. Normal stresses in the ship's longitudinal direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21/27 2.1 Normal stresses from vertical bending moments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21/27 2.2 Normal stresses due to horizontal bending moments . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21/27 2.3 Normal stresses from torsion of the ship's hull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21/27 3. Shear stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22/27 3.1 Shear stresses due to vertical shear forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22/27 3.2 Shear stresses due to horizontal shear forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23/27 3.3 Shear stresses due to torsional moments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23/27 E. Permissible Still Water Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23/27 1. Vertical bending moments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23/27 2. Vertical shear forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-24/27 3. Static torsional moments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-25/27 F. Guidance Values for Large Deck Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-25/27 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-25/27 2. Guidance values for the determination of the section modulus . . . . . . . . . . . . . . . . . . . . . . . . 5-25/27 3. Guidance values for the design of transverse box girders of container ships . . . . . . . . . . . . . . 5-26/27 4. Guidance values for the displacements of the upper girder of the ship . . . . . . . . . . . . . . . . . . 5-27/27 G. Bulk Carriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27/27 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27/27 2. Flooding criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27/27 3. Flooding conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27/27 Section 6 - Shell Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1/20 A. General, Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1/20 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1/20 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1/20 B. Bottom Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1/20 1. Plate thickness based on load stress criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1/20 1.1 Ships with lengths L < 90 m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1/20 1.2 Ships with length L > 90 m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1/20 BKI - Rules for Hull - 2014
- 10. Table of Contentsviii Page 2. Critical plate thickness, buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2/20 2.1 Guidance values for critical plate thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2/20 2.2 Buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2/20 3. Minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2/20 4. Bilge strake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2/20 5. Flat plate keel and garboard strake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3/20 C. Side Shell Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4/20 1. Plate thickness based on load stress criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4/20 1.1 Ships with lengths L < 90 m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4/20 1.2 Ships with lengths L 90 m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4/20 2. Minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4/20 3. Sheerstrake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5/20 4. Buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5/20 5. Strengthenings for harbour and tug manoeuvres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5/20 D. Side Plating of Superstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6/20 E. Strengthening of Bottom Forward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6/20 1. Arrangement of floors and girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6/20 2. Bottom plating forward of = 0,5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6/20 3. Stiffeners forward of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6/20 F. Strengthenings in Way of Propellers and Propeller Shaft Brackets, Bilge Keels . . . . . . . . . . . . . . . 6-7/20 1. Strengthenings in way of propellers and propeller brackets . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7/20 2. Bilge keels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7/20 G. Openings in the Shell Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7/20 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7/20 2. Pipe connections at the shell plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8/20 H. Bow Doors and Inner Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8/20 1. General, definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8/20 1.1 Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8/20 1.2 Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9/20 1.3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9/20 2. Strength criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9/20 3. Design loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10/20 3.1 Bow doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10/20 3.2 Inner doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12/20 4. Scantlings of bow doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12/20 4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12/20 4.2 Plating and secondary stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12/20 4.3 Primary structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12/20 5. Scantlings of inner doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12/20 6. Securing and supporting of bow doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13/20 6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13/20 6.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13/20 7. Arrangement of securing and locking devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14/20 7.1 Systems for operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14/20 7.2 Systems for indication/monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15/20 8. Operating and maintenance manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16/20 J. Side Shell Doors and Stern Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16/20 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16/20 2. Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16/20 3. Strength criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17/20 4. Design loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17/20 5. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17/20 5.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17/20 5.2 Plating and secondary stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 5.3 Primary structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 6. Securing and supporting of side shell and stern doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 6.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 7. Arrangement of securing and locking devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 7.1 Systems for operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 BKI - Rules for Hull - 2014
- 11. Table of Contents ix Page 7.2 Systems for indication/monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 8. Operating and maintenance manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18/20 K. Bulwarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19/20 Section 7 - Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1/9 A. Strength Deck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1/9 1. General, Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1/9 2. Connection between strength deck and sheerstrake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1/9 3. Openings in the strength deck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1/9 4. Scantlings of strength deck of ships up to 65 m in length . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5/9 5. Scantlings of strength deck of ships of more than 65 m in length . . . . . . . . . . . . . . . . . . . . . . 7-5/9 6. Minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5/9 7. End thickness, thickness inside line of hatchways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5/9 B. Lower Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6/9 1. Thickness of decks for cargo loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6/9 2. Thickness of decks for wheel loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6/9 3. Machinery decks and accommodation decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7/9 C. Helicopter Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7/9 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7/9 2. Design Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8/9 2.1 LC 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8/9 2.2 LC 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8/9 2.3 LC 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8/9 3. Scantlings of structural members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9/9 Section 8 - Bottom Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1/13 A. Single Bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1/13 1. Floor plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1/13 1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1/13 1.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1/13 2. Longitudinal girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2/13 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2/13 2.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2/13 B. Double Bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2/13 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2/13 2. Centre girder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3/13 2.1 Lightening holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3/13 2.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3/13 3. Side girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4/13 3.1 Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4/13 3.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4/13 4. Inner bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4/13 5. Double bottom tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5/13 5.1 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5/13 5.2 Fuel and lubricating oil tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5/13 5.3 Bilge wells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5/13 5.4 Sea chests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5/13 6. Double bottom, transverse framing system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6/13 6.1 Plate floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6/13 6.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6/13 6.3 Watertight floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6/13 6.4 Bracket floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7/13 6.5 Brackets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7/13 6.6 Struts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7/13 7. Double bottom, longitudinal framing system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7/13 7.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7/13 7.2 Bottom and inner bottom longitudinals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7/13 7.3 Plate floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8/13 7.4 Brackets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8/13 7.5 Longitudinal girder system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8/13 8. Direct calculation of bottom structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8/13 BKI - Rules for Hull - 2014
- 12. Table of Contentsx Page 8.1 General, Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8/13 8.2 Design loads, permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9/13 8.3 Buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9/13 9. Testing for tightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9/13 C. Bottom Structure in Machinery Spaces in Way of the Main Propulsion Plant . . . . . . . . . . . . . . . . . 8-10/13 1. Single bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10/13 2. Double bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10/13 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10/13 2.2 Plate floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10/13 2.3 Side girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10/13 2.4 Inner bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11/13 3. Engine seating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11/13 3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11/13 3.2 Longitudinal girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11/13 D. Docking Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12/13 1. Simplified docking calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12/13 2. Direct docking calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13/13 3. Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13/13 4. Buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13/13 Section 9 - Framing System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1/12 A. Transverse Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1/12 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1/12 1.1 Frame spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1/12 1.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1/12 2. Main frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2/12 2.1 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2/12 2.2 Frames in tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2/12 2.3 End attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3/12 3. 'Tween deck and superstructure frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3/12 3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3/12 3.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3/12 3.3 End attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3/12 4. Peak frames and frames in way of the stern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3/12 4.1 Peak frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3/12 4.2 Frames in way of the stern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4/12 5. Strengthenings in fore- and aft body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4/12 5.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4/12 5.2 Tiers of beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4/12 5.3 Web frames and stringers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4/12 5.4 Web frames and stringers in 'tween decks and superstructure decks . . . . . . . . . . . . . . . . 9-5/12 5.5 Tripping brackets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5/12 6. Web frames in machinery spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6/12 6.1 Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6/12 6.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6/12 B. Bottom, Side- and Deck Longitudinals, Side Transverses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7/12 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7/12 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7/12 3. Scantlings of longitudinals and longitudinal beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-9/12 4. Side transverses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-12/12 5. Strengthenings in the fore and aft body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-12/12 Section 10 - Deck Beams and Supporting Deck Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1/5 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1/5 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1/5 2. Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1/5 3. Buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2/5 B. Deck Beams and Girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2/5 1. Transverse deck beams and deck longitudinals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2/5 2. Deck longitudinals in way of the upper and lower hull flange . . . . . . . . . . . . . . . . . . . . . . . . . 10-2/5 3. Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2/5 BKI - Rules for Hull - 2014
- 13. Table of Contents xi Page 4. Girders and transverses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2/5 5. Supporting structure of windlasses and chain stoppers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3/5 C. Pillars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3/5 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3/5 2. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3/5 D. Cantilevers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4/5 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4/5 2. Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4/5 E. Hatchway Girders and Girders Forming Part of the Longitudinal Hull Structure . . . . . . . . . . . . . . 10-5/5 Section 11 - Watertight Bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1/8 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1/8 1. Watertight subdivision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1/8 2. Arrangement of watertight bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1/8 2.1 Collision bulkhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1/8 2.2 Stern tube and remaining watertight bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3/8 3. Openings in watertight bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3/8 3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3/8 3.2 Hinged doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3/8 3.3 Sliding doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3/8 3.4 Penetrations through watertight bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4/8 B. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4/8 1. General, Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4/8 2. Bulkhead plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4/8 3. Stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-5/8 4. Corrugated bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-5/8 5. Primary Supporting Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-6/8 5.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-6/8 5.2 Load assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-6/8 5.3 Strength criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-6/8 6. Watertight longitudinal structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-8/8 C. Shaft Tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-8/8 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-8/8 2. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-8/8 Section 12 - Tank Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1/10 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1/10 1. Subdivision of tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1/10 2. Air, overflow and sounding pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1/10 3. Forepeak tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1/10 4. Cross references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1/10 5. Separation of fuel oil tanks from tanks for other liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1/10 6. Tanks for heated liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2/10 7. Minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2/10 8. Plating and stiffeners in the propeller area and in the engine room . . . . . . . . . . . . . . . . . . . . . 12-3/10 8.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3/10 8.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3/10 8.3 Shell structures in propeller area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3/10 8.4 Tank structures in propeller area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3/10 8.5 Tank structures in main engine area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-4/10 B. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-4/10 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-4/10 2. Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-5/10 3. Stiffeners and girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-5/10 4. Corrugated bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7/10 5. Thickness of clad plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7/10 C. Tanks with Large Lengths or Breadths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7/10 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7/10 2. Hold spaces for ballast water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-8/10 D. Vegetable Oil Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-8/10 E. Detached Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9/10 BKI - Rules for Hull - 2014
- 14. Table of Contentsxii Page 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9/10 2. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9/10 F. Potable Water Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9/10 G. Swash Bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9/10 H. Testing for Tightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-10/10 Section 13 - Stem and Sternframe Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1/8 A. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1/8 B. Stem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1/8 1. Bar stem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1/8 2. Plate stem and bulbous bows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1/8 C. Sternframe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1/8 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1/8 2. Propeller post . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2/8 3. Rudder post and rudder axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3/8 4. Sole piece . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-4/8 5. Rudder horn of semi spade rudders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5/8 D. Propeller Brackets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-7/8 E. Elastic Stern Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-7/8 1. Strength analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-7/8 1.1 Static load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-8/8 1.2 Dynamic load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-8/8 Section 14 Rudder and Manoeuvring Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1/21 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1/21 1. Manoeuvring arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1/21 2. Structural details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1/21 3. Size of rudder area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2/21 4. Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2/21 5. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3/21 B. Rudder Force and Torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4/21 1. Rudder force and torque for normal rudders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4/21 2. Rudder force and torque for rudder blades with cut-outs (semi-spade rudders) . . . . . . . . . . . . 14-5/21 C. Scantlings of the Rudder Stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6/21 1. Rudder stock diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6/21 2. Strengthening of rudder stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-7/21 3. Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-7/21 3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-7/21 3.2 Data for the analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-7/21 3.3 Moments and forces to be evaluated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-10/21 4. Rudder trunk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-11/21 D. Rudder Couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-12/21 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-12/21 2. Horizontal couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-12/21 3. Vertical couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-12/21 4. Cone couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-13/21 4.1 Cone couplings with key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-13/21 4.2 Cone couplings with special arrangements for mounting and dismounting the couplings 14-14/21 E. Rudder Body, Rudder Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-16/21 1. Strength of rudder body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-16/21 2. Rudder plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-17/21 2.1 Double plate rudders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-17/21 2.2 Single plate rudders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-18/21 2.2.1 Main piece diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-18/21 2.2.2 Blade thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-18/21 2.2.3 Arms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-18/21 3. Transmitting of the rudder torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-18/21 4. Rudder bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-18/21 5. Pintles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-19/21 6. Guidance values for bearing clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-19/21 F. Design Yield Moment of Rudder Stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-20/21 BKI - Rules for Hull - 2014
- 15. Table of Contents xiii Page G. Stopper, Locking Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-20/21 H. Propeller Nozzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-20/21 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-20/21 2. Design pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-20/21 3. Plate thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-21/21 4. Section modulus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-21/21 5. Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-21/21 Section 15 - Strengthening for Navigation in Ice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1/17 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1/17 1. Ice class notations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1/17 2. Ice class draught for Ships with Notations ES1-ES4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-2/17 3. Propulsion machinery output for ships with Notations ES1-ES4 . . . . . . . . . . . . . . . . . . . . . . . 15-2/17 4. Definitions for ships notations ES1-ES4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-5/17 B. Requirements for the Notations ES1 – ES4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-7/17 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-7/17 2. Ice loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-8/17 3. Thickness of shell plating in the ice belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-9/17 4. Frames, ice stringers, web frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-10/17 4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-10/17 4.2 Transverse frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-10/17 4.3 Longitudinal frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-12/17 4.4 Ice stringers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-12/17 4.5 Web frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-13/17 5. Stem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-15/17 6. Arrangements for towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-16/17 7. Stern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-16/17 8. Bilge keels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-16/17 9. Rudder and steering gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-16/17 C. Requirements for the Ice Class Notation ES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-17/17 1. Shell plating within the ice belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-17/17 2. Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-17/17 3. Stem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-17/17 Section 16 - Superstructures and Deckhouses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1/10 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1/10 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1/10 2. Arrangement of superstructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1/10 3. Strengthenings at the ends of superstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1/10 4. Transverse structure of superstructures and deckhouses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-2/10 5. Openings in closed superstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-2/10 6. Recommendations regarding deckhouse vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-2/10 B. Side Plating and Decks of Non-Effective Superstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-2/10 1. Side plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-2/10 2. Deck plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3/10 3. Deck beams, supporting deck structure, frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3/10 C. Superstructure End Bulkheads and Deckhouse Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3/10 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3/10 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3/10 3. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-5/10 3.1 Stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-5/10 3.2 Plate thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-5/10 D. Decks of Short Deckhouses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-5/10 1. Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-5/10 2. Deck beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-5/10 E. Elastic Mounting of Deckhouses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-6/10 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-6/10 2. Design loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-6/10 2.1 Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-6/10 2.2 Water pressure and wind pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-7/10 BKI - Rules for Hull - 2014
- 16. Table of Contentsxiv Page 2.3 Load on the deckhouse bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-7/10 2.4 Load on deck beams and girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-7/10 3. Load cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-7/10 4. Scantlings of rails, mounting elements and substructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-8/10 4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-8/10 4.2 Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-8/10 5. Corrosion Addition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-9/10 F. Breakwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-9/10 1. Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-9/10 2. Dimensions of the breakwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-9/10 3. Cutouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-10/10 4. Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-10/10 5. Plate thickness and stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-10/10 6. Primary supporting members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-10/10 7. Proof of buckling strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-10/10 Section 17 - Hatchways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1/20 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1/20 1. Hatchways on freeboard and superstructure decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1/20 2. Hatchways on lower decks and within superstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1/20 3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1/20 B. Hatch Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2/20 1. Design loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2/20 1.1 Load case A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2/20 1.2 Load case B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2/20 1.3 Load case C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-3/20 1.4 Load case D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-4/20 1.5 Load case E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-5/20 1.6 Load case F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-5/20 1.7 Horizontal mass forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-5/20 2. Permissible stresses and deflections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-5/20 3. Strength calculation for hatch covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-5/20 3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-5/20 3.2 Hatch cover supports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-6/20 3.3 Strength calculations for beam and girder grillages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-6/20 3.4 FEM calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-6/20 4. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-6/20 4.1 Hatch cover plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-6/20 4.1.1 Top plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-6/20 4.1.2 Lower plating of pontoon hatch covers and box girders . . . . . . . . . . . . . . . . . 17-7/20 4.2 Main girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-7/20 4.3 Edge girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-7/20 4.4 Hatch cover stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-7/20 4.5 Hatch cover supports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-8/20 4.6 Locking and securing of hatch covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-9/20 4.7 Hatch cover stoppers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-9/20 4.8 Cantilevers, load transmitting elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-10/20 4.9 Container seatings on hatch covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-10/20 5. Weathertightness of hatch covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-10/20 5.1 Packing material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-10/20 5.2 Non-weathertightness hatch covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-10/20 5.3 Drainage arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-11/20 5.4 Tightness test, trials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-11/20 6. Wooden hatchway covers & hatchway beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-12/20 6.1 Hatchway covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-12/20 6.2. Hatchway beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-12/20 6.2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-12/20 6.2.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-12/20 6.3. Moments of inertia, section moduli, shear areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-13/20 6.4 Arrangement and securing of hatchway beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-13/20 BKI - Rules for Hull - 2014
- 17. Table of Contents xv Page 7. Sealing and Securing Arrangements of Wooden and Non Self Tightening Pontoon Hatchway Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-14/20 C. Hatch Cover Coamings and Girders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-14/20 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-14/20 2. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-15/20 2.1 Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-15/20 2.2 Coaming stays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-15/20 2.3 Horizontal stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-15/20 D. Smaller Opening and Hatches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-16/20 1. Miscellaneous openings in freeboard and superstructure decks . . . . . . . . . . . . . . . . . . . . . . . 17-16/20 2. Strength and securing of small hatches on the exposed fore deck . . . . . . . . . . . . . . . . . . . . . . 17-16/20 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-16/20 2.2 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-16/20 2.3 Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-17/20 2.4 Primary securing devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-17/20 2.5 Requirements for primary securing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-17/20 2.6 Secondary securing device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-18/20 E. Engine and Boiler Room Hatchways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-18/20 1. Deck openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-18/20 2. Engine and boiler room casings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-18/20 3. Doors in engine and boiler room casings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-19/20 Section 18 - Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1/10 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1/10 B. Equipment Numeral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1/10 C. Anchors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2/10 D. Chain Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-3/10 E. Chain Locker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-4/10 F. Mooring Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-5/10 1. Ropes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-5/10 2. Shipboard fittings (mooring bollards and bitts, fairleads, stand rollers, chocks) . . . . . . . . . . . 18-6/10 3. Supporting hull structure for mooring equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-6/10 4. Corrosion addition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-7/10 5. Equipment for mooring at single point moorings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-7/10 G. Towing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-8/10 H. Towing and Mooring Arrangements Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-9/10 Section 19 - Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1/20 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1/20 1. Information contained in manufacturing documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1/20 2. Materials, weldability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1/20 3. Manufacture and testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1/20 B. Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2/20 1. General design principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2/20 2. Design details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2/20 2.1 Stress flow, transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2/20 2.2 Local clustering of welds, minimum spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-3/20 2.3 Welding cut-outs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-3/20 2.4 Local reinforcements, doubling plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-3/20 2.5 Intersecting members, stress in the thickness direction . . . . . . . . . . . . . . . . . . . . . . . . . . 19-4/20 2.6 Welding of cold formed sections, bending radii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-4/20 2.7 Build - up welds on rudderstocks and pintles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-5/20 3. Weld shapes and dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-5/20 3.1 Butt joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-5/20 3.2 Corner, T and double-T (cruciform) joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-6/20 3.3 Fillet weld connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-8/20 4. Welded joints of particular components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-10/20 4.1 Welds at the ends of girders and stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-10/20 4.2 Joints between section ends and plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-11/20 4.3 Welded shaft bracket joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-11/20 4.4 Rudder coupling flanges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-12/20 BKI - Rules for Hull - 2014
- 18. Table of Contentsxvi Page C. Stress Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-14/20 1. General analysis of fillet weld stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-14/20 1.1 Definition of stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-14/20 1.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-14/20 2. Determination of stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-14/20 2.1 Fillet welds stressed by normal and shear forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-14/20 2.2 Fillet weld joints stressed by bending moments and shear forces . . . . . . . . . . . . . . . . . . . 19-16/20 2.3 Fillet welded joints stressed by bending and torsional moments and shear forces . . . . . . 19-16/20 2.4 Continuous fillet welded joints between web and flange of bending girders . . . . . . . . . . 19-17/20 2.5 Intermittent fillet weld joints between web and flange of bending girders . . . . . . . . . . . . 19-17/20 2.6 Fillet weld connections on overlapped profile joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-17/20 2.7 Bracket joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-18/20 2.8 Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-18/20 Section 20 - Fatigue Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1/21 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1/21 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1/21 2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-2/21 3. Quality requirements (fabrication tolerances) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-4/21 B. Fatigue Strength Analysis for Free Plate Edges and for Welded Joints Using Detail Classification . 20-5/21 1. Definition of nominal stress and detail Classification for welded joints . . . . . . . . . . . . . . . . . . 20-5/21 2. Permissible stress range for standard stress range spectra or calculation of the cumulative damage ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-5/21 3. Design S-N Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-6/21 3.1 Description of the design S-N curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-6/21 3.2 Correction of the reference value of the design S-N curve . . . . . . . . . . . . . . . . . . . . . . . . 20-7/21 C. Fatigue Strength Analysis for Welded Joints Based on Local Stresses . . . . . . . . . . . . . . . . . . . . . . . 20-10/21 Section 21 - Hull Outfit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1/21 A. Partition Bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1/21 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1/21 2. Partition bulkheads between engine and boiler rooms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1/21 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1/21 2.2 Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1/21 B. Ceiling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1/21 1. Bottom ceiling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1/21 2. Side ceiling, ceiling at tank bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2/21 C. Side Scuttles, Windows and Skylights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2/21 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2/21 2. Design Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-3/21 3. Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-3/21 4. Glass panes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-3/21 5. Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-4/21 D. Scuppers, Sanitary Discharges and Freeing Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-4/21 1. Scuppers and sanitary discharges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-4/21 2. Freeing ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-4/21 E. Air Pipes, Overflow Pipes, Sounding Pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-5/21 F. Ventilators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-8/21 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-8/21 2. Closing appliances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-9/21 G. Stowage of Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-9/21 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-9/21 2. Load assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-9/21 3. Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-10/21 H. Lashing Arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-10/21 J. Car Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-10/21 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-10/21 2. Design loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-10/21 3. Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-11/21 4. Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-11/21 5. Permissible deflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-11/21 BKI - Rules for Hull - 2014
- 19. Table of Contents xvii Page 6. Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-12/21 K. Life Saving Appliances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-12/21 L. Signal and Radar Masts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-12/21 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-12/21 2. Single tubular masts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-12/21 2.1 Stayed masts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-12/21 2.2 Unstayed masts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-13/21 3. Box girder and frame work masts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-13/21 4. Structural details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-13/21 M. Loading and Lifting Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-14/21 N. Access to Cargo Area of Oil Tankers and Bulk Carriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-14/21 1. Safe access to cargo holds, cargo tanks, ballast tanks and other spaces . . . . . . . . . . . . . . . . . 21-14/21 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-14/21 3. Technical provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-15/21 4. Ship structure access manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-21/21 O. Guard - Rails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-21/21 P. Access to Ships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-21/21 Section 22 - Structural Fire Protection on Board Seagoing Ships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1/49 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1/49 B. Regulations on Fire Protection for Passenger Ships carrying more than 36 Passengers . . . . . . . . . 22-2/49 1. Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-2/49 2. Main vertical zones and horizontal zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-2/49 3. Bulkheads within main vertical zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-2/49 4. Fire integrity of bulkheads and decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-3/49 5. Protection of stairways and lifts in accommodation and service spaces . . . . . . . . . . . . . . . . . 22-7/49 6. Openings in "A" class divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-8/49 7. Openings in "B" class divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-9/49 8. Windows and sidescuttles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-10/49 9. Ventilation systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-10/49 10. Restriction of combustible materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-13/49 11. Details of construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-14/49 12. Means of escape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-15/49 13. Fixed fire detection and fire alarm systems and automatic sprinkler, fire detection and fire alarm systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-18/49 14. Protection of vehicle, special category and ro-ro spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-18/49 15. Special arrangements in machinery spaces of category A . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-19/49 16. Special requirements for ships carrying dangerous goods . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-20/49 C. Regulations on Fire Protection for Passenger Ships carrying not more than 36 Passengers . . . . . . 22-20/49 1. Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-20/49 2. Main vertical zones and horizontal zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-20/49 3. Bulkheads within main vertical zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-21/49 4. Fire integrity of bulkheads and decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-21/49 5. Protection of stairways and lifts in accommodation and service spaces . . . . . . . . . . . . . . . . . 22-24/49 6. Openings in "A" class divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-24/49 7. Openings in "B" class divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-26/49 8. Windows and side scuttles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-27/49 9. Ventilation systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-27/49 10. Restriction of combustible materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-29/49 11. Details of construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-30/49 12. Means of escape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-30/49 13. Fixed fire detection and fire alarm systems and automatic sprinkler, fire detection and fire alarm systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-32/49 14. Protection of vehicle, special category and ro-ro spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-32/49 15. Special arrangements in machinery spaces of category A . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-33/49 16. Special requirements for ships carrying dangerous goods . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-34/49 D. Regulations on Fire Protection for Cargo Ships of 500 GT and over . . . . . . . . . . . . . . . . . . . . . . . . 22-34/49 1. Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-34/49 2. Accommodation and service spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-35/49 3. Bulkheads within the accommodation and service spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-35/49 BKI - Rules for Hull - 2014
- 20. Table of Contentsxviii Page 4. Fire integrity of bulkheads and decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-35/49 5. Protection of stairways and lift trunks in accommodation spaces, service spaces and control stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-38/49 6. Openings in fire resisting divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-38/49 7. Ventilation systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-39/49 8. Restricted use of combustible materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-40/49 9. Details of construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-41/49 10. Fixed fire detection and fire alarm systems, automatic sprinkler, fire detection and fire alarm systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-41/49 11. Means of escape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-41/49 12. Miscellaneous items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-43/49 13. Protection of cargo spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-43/49 14. Protection of vehicle and ro-ro spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-43/49 15. Special requirements for ships carrying dangerous goods . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-43/49 E. Regulations on Fire Protection for Cargo Ships of less than 500 GT . . . . . . . . . . . . . . . . . . . . . . . . 22-44/49 F. Regulations on Fire Protection for Oil Tankers of 500 GT and over . . . . . . . . . . . . . . . . . . . . . . . . . 22-44/49 1. Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-44/49 2. Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-45/49 3. Structure, bulkheads within accommodation and service spaces and details of construction 22-45/49 4. Fire integrity of bulkheads and decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-45/49 Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1/27 A. Strengthenings for Bulk Cargo and Heavy Cargo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1/27 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1/27 2. Double bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1/27 3. Longitudinal strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1/27 B. Bulk Carriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1/27 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1/27 2. Longitudinal strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-2/27 3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-2/27 4. Scantlings of bottom structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-2/27 5. Side Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-3/27 5.1 Side longitudinals, longitudinal stiffeners, main frames . . . . . . . . . . . . . . . . . . . . . . . . . 23-3/27 5.2 Main frames and end connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-3/27 5.3 Minimum thickness of side shell plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-4/27 5.4 Weld connections of frames and end brackets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-4/27 6. Topside tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-4/27 7. Transverses in the wing tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-4/27 8. Cargo hold bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-4/27 9. Hatchway coamings, longitudinal bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-6/27 10. Loading information for Bulk Carriers, Ore Carriers and Combination Carriers . . . . . . . . . . . 23-6/27 C. Ore Carriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-7/27 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-7/27 2. Double bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-8/27 3. Transverse and longitudinal bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-8/27 D. Allowable hold loading, considering flooding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-8/27 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-8/27 2. Load model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-8/27 3. Shear capacity of the double bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-9/27 4. Allowable hold loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-11/27 E. Evaluation of Scantlings of Corrugated Transverse Watertight Bulkheads in Bulk Carriers Considering Hold Flooding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-12/27 1. Application and definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-12/27 2. Load model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-12/27 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-12/27 2.2 Bulkhead corrugation flooding head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-13/27 2.3 Pressure in the non-flooded bulk cargo loaded holds . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-14/27 2.4 Pressure in the flooded holds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-14/27 2.5 Resultant pressure and force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-15/27 BKI - Rules for Hull - 2014
- 21. Table of Contents xix Page 3. Bending moment and shear force in the bulkhead corrugations . . . . . . . . . . . . . . . . . . . . . . . 23-17/27 3.1 Bending moment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-17/27 3.2 Shear force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-17/27 4. Strength criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-17/27 4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-17/27 4.1.1 Lower stool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-17/27 4.1.2 Upper stool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-18/27 4.1.3 Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-18/27 4.2 Bending capacity and shear stress t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-18/27 4.3 Section modulus at the lower end of corrugations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-19/27 4.4 Section modulus of corrugations at cross-sections other than the lower end . . . . . . . . . . 23-22/27 4.5 Allowable stress check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-22/27 4.6 Effective compression flange width and shear buckling check . . . . . . . . . . . . . . . . . . . . 23-22/27 4.6.1 Effective width of the compression flange of corrugations . . . . . . . . . . . . . . 23-22/27 4.6.2 Shear buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-22/27 4.7 Local net plate thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-22/27 5. Shedder and gussed plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-23/27 6. Corrosion addition and steel renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-23/27 F. Harmonised Notations and Corresponding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-23/27 1. Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-23/27 2. Harmonized notations and annotations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-23/27 2.1 Notations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-23/27 2.2 Additional Notations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-23/27 3. Design loading conditions (General) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-24/27 3.1 BC-C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-24/27 3.2 BC-B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-24/27 3.3 BC-A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-24/27 3.4 Ballast conditions (applicable to all Notations) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-24/27 3.4.1 Ballast tank capacity and disposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-24/27 3.4.2 Strength requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-25/27 4. Departure and arrival conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-25/27 5. Design loading conditions (for local strength) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-25/27 5.1 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-25/27 5.2 General conditions applicable for all Notations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-25/27 5.3 Condition applicable for all Notations, except when Notation {no MP} is assigned . . . 23-25/27 5.4 Additional conditions applicable for BC-A Notation only . . . . . . . . . . . . . . . . . . . . . . . 23-26/27 5.5 Additional conditions applicable for ballast hold(s) only . . . . . . . . . . . . . . . . . . . . . . . . 23-26/27 5.6 Additional conditions applicable during loading and unloading in harbour only . . . . . . 23-26/27 5.7 Hold mass curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-26/27 G. Fitting of Forecastle of Bulk Carrier, Ore Carriers and Combination Carriers . . . . . . . . . . . . . . . . 23-27/27 1. Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-27/27 2. Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-27/27 Section 24 - Oil Tankers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-1/32 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-1/32 1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-1/32 2. Character of Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2/32 3. Cargo Tank Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2/32 3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2/32 3.2 Double hull requirements for oil tankers of 5.000 tdw and above . . . . . . . . . . . . . . . 24-3/32 3.3 Double hull requirements for oil tankers of less than 5.000 tdw . . . . . . . . . . . . . . . . . . . 24-4/32 3.4 Limitation of cargo tank length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-4/32 4. Ship Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-5/32 4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-5/32 4.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-5/32 4.3 Location and separation of spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-7/32 4.4 Arrangement of doors windows and air inlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-8/32 4.5 Pipe tunnels in double bottoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-8/32 4.6 Slop tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-8/32 5. Bow or stern loading and unloading arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-9/32 BKI - Rules for Hull - 2014
- 22. Table of Contentsxx Page 6. Superstructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-10/32 7. Gangways, bulwarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-10/32 8. Ventilators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-10/32 9. Anchor equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-11/32 10. Cathodic protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-11/32 11. Aluminium paints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-11/32 12. Access to spaces in the cargo area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-11/32 13. Minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-12/32 14. Corrosion protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-13/32 15. Testing of cargo and ballast tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-13/32 B. Strength of Girders and Transverses in the Cargo Tank Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-14/32 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-14/32 2. Stress analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-14/32 2.1 Structural modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-14/32 2.2 Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-14/32 2.3 Permissible stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-16/32 2.3.1 Transverse members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-16/32 2.3.2 Longitudinal members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-16/32 2.4 Fatigue strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-17/32 2.5 Cross ties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-17/32 C. Oiltight Longitudinal and Transverse Bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-17/32 1. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-17/32 2. Cofferdam bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-17/32 D. Wash Bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 2. Scantlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 E. Hatches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 1. Tank hatches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 2. Other access arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 F. Structural Details at the Ship's End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 2. Fore body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-18/32 3. Aft body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-19/32 4. Emergency towing arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-19/32 4.1 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-19/32 4.2 Requirements for the arrangements and components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-19/32 4.2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-19/32 4.2.2 Documents to be submitted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-19/32 4.2.3 Strength of the towing components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-19/32 4.2.4 Length of towing pennant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20/32 4.2.5 Location of strongpoint and fairlead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20/32 4.2.6 Strongpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20/32 4.2.7 Fairleads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20/32 4.2.8 Chafing gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20/32 4.2.9 Towing connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20/32 4.2.10 Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20/32 4.3 Ready availability of towing arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20/32 G. Ships for the Carriage of Dry Cargo or Oil in Bulk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-21/32 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-21/32 2. Reinforcements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-21/32 3. Slop tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-21/32 H. Small Tankers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-22/32 l. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-22/32 2. Girders and transverses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-22/32 3. Transverse framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-22/32 4. Deck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-23/32 5. Shell plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-23/32 J. Product List 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-24/32 K. Product List 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-25/32 L. Additional Requirements for Tankers in Shuttle Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-26/32 BKI - Rules for Hull - 2014
- 23. Table of Contents xxi Page 1. General requirements and instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-26/32 1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-26/32 1.2 Exemptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-27/32 1.3 Notations affixed to the Character of Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-27/32 1.4 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-27/32 1.5 Documents for approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-27/32 2. System requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-28/32 2.1 Requirements for Single Point Mooring (SPM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-28/32 2.1.1 Bow chain stoppers and fairleads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-28/32 2.1.2 Bow loading arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-29/32 2.1.3 Fire fighting arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-29/32 2.1.4 Electrical equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-30/32 2.2 Requirements for Submerged Turret Loading (STL) . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-30/32 2.3 Arrangement of forward spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-30/32 2.4 Functional requirements for bow and STL loading systems . . . . . . . . . . . . . . . . . . . . . . 24-31/32 2.4.1 Control systems, communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-31/32 2.4.2 Operation manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-31/32 3. Surveys and tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-32/32 3.1 Tests of components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-32/32 3.2 Tests after installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-32/32 3.3 Periodical inspections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-32/32 Section 25 - Ships Carrying Dangerous Chemicals in Bulk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-1/1 Section 26 - Ships Carrying Liquefied Gases in Bulk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1/1 Section 27 - Tugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-1/13 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-1/13 1. Scope, application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-1/13 2. Classification, Notations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-1/13 3. Approval documents, documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-1/13 B. Hull Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-2/13 1. Scantlings, general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-2/13 2. Deck structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-2/13 3. Fore body, bow structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-2/13 4. Stern frame, bar keel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-2/13 5. Side structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-2/13 6. Engine room casing, superstructures and deckhouses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-2/13 7. Foundations of towing gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-3/13 8. Ice strengthening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-3/13 C. Towing Gear/Towing Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-3/13 1. General design requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-3/13 2. Definition of loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-3/13 3. Towing hook and slip device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-4/13 4. Towropes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-4/13 5. Towing winches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-5/13 6. Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-6/13 D. Steering Gear/Steering Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-8/13 1. Steering stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-8/13 2. Rudder movement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-8/13 3. Tugs operating as pusher units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-8/13 4. Special steering arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-8/13 E. Anchoring/Mooring Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-8/13 1. Equipment numeral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-8/13 2. General requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-9/13 3. Tugs operating as pusher units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-9/13 F. Weathertight Integrity and Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-9/13 1. Weather deck openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-9/13 2. Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-9/13 G. Escape Routes and Safety Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 1. Engine room exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 BKI - Rules for Hull - 2014
- 24. Table of Contentsxxii Page 2. Companionways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 3. Rudder compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 4. Access to bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 5. Safe handling of towing gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 6. Fire safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 H. Additional Requirements for Active Escort Tugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 1. Scope, application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 2. Classification, Notations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 3. Characteristics of Active Escort Tugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-10/13 4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-11/13 5. Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-11/13 6. Arrangement and design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-11/13 7. Stability of Active Escort Tugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-12/13 8. Full Scale Trials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-13/13 Section 28 - Fishing Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28-1/1 Section 29 - Passenger Ships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-1/4 I. Passenger Ships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-1/4 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-1/4 B. Documents for Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-1/4 C. Watertight Subdivision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-1/4 D. Double Bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-1/4 E. Openings in the Shell Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-1/4 F. Materials for Closures of Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-2/4 G. Cross-Flooding Arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-2/4 H. Pipe Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-2/4 II. Special Purpose Ships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-3/4 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-3/4 1. Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-3/4 2. Structural Fire Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-3/4 3. Character of Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-3/4 B. Documents for Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-3/4 C. Watertight Subdivision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-3/4 Section 30 - Ships for Sheltered Shallow Water Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1/3 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1/3 B. Shell Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1/3 C. Watertight Bulkheads and Tank Bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1/3 D. Deck Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2/3 1. Hatchways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2/3 2. Casings, companionways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-2/3 E. Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-3/3 Section 31 - Barges and Pontoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1/4 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1/4 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1/4 2. Validity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1/4 3. Character of Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1/4 4. General indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1/4 5. Deck cargo load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1/4 B. Longitudinal Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1/4 C. Watertight Bulkheads and Tank Bulkheads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-2/4 D. Structural Details at the Ends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-2/4 E. Rudder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-2/4 F. Pushing and Towing Devices, Connecting Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-2/4 G. Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-3/4 H. Cargo Retaining Arrangements of Deck Cargo Barge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-4/4 Section 32 - Dredgers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-1/8 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-1/8 BKI - Rules for Hull - 2014
- 25. Table of Contents xxiii Page B. Documents for Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-1/8 C. Principal Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-2/8 D. Longitudinal Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-2/8 E. Shell Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-2/8 F. Deck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-2/8 G. Bottom Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-3/8 1. Single bottom transversely framed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-3/8 2. Single bottom longitudinally framed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-3/8 3. Double bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-4/8 H. Hopper and Well Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-4/8 J. Box Keel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-5/8 K. Stern Frame and Rudder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-6/8 L. Bulwark, Overflow Arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-6/8 M. Self-Unloading Barges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-6/8 N. Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-7/8 Section 33 - Special Rules of Floating Docks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33-1/1 Section 34 - Supply Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-1/3 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-1/3 1. Application, character of classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-1/3 2. Stability, floatability in damaged condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-1/3 B. Shell Plating, Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-1/3 1. Shell plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-1/3 2. Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-2/3 C. Weather Deck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-2/3 D. Superstructures and Deckhouses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-2/3 E. Access to Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-2/3 l. Access to the machinery space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-2/3 2. Access to spaces below the exposed cargo deck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-3/3 F. Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-3/3 Section 35 - Strengthening Against Collisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35-1/5 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35-1/5 B. Calculation of the Deformation Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35-1/5 C. Computation of the Critical Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35-4/5 Section 36 - Subdivision and Stability of Cargo Ships and Passenger Ships . . . . . . . . . . . . . . . . . . . . . . . 36-1/4 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-1/4 1. Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-1/4 2. Character of Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-1/4 3. Documents for approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-1/4 B. Onboard Stability Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-1/4 C. Double Bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-2/4 D. Watertight Bulkheads and Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-2/4 E. External Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-3/4 F. Cross-Flooding Arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-3/4 Section 37 - Special Requirements for In-Water Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37-1/2 A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37-1/2 B. Special Arrangements for In-Water Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37-1/2 C. Documents for Approval, Trials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37-1/2 Section 38 - Corrosion Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-1/7 A. General Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-1/7 1. Field of Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-1/7 B. Shop Primers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-1/7 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-1/7 2. Approvals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-1/7 C. Hollow Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 D. Combination of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 BKI - Rules for Hull - 2014
- 26. Table of Contentsxxiv Page 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 E. Fitting-Out and Berthing Periods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 F. Corrosion Protection of Ballast Water Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 2. Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-2/7 3. Coatings combined with cathodic protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-4/7 G. Corrosion Protection of Cargo Holds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-6/7 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-6/7 2. Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-6/7 H. Corrosion Protection of the Underwater Hull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-7/7 1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-7/7 2. Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-7/7 Annex A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1/3 I. Biro Klasifikasi Indonesia Freeboard Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1/3 II. Ice Class Draught Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3/3 BKI - Rules for Hull - 2014
- 27. Rules Amendment Notice xxv Rules Amendment Notice These pages contain amendment within he following Sections of the Rules for Classification and Surveys, 2014 Edition These amendment are effective from 1st January and 1st July 2014 Paragraph Title/ Subject Status/ Remarks Section 1. General, Definitions E. Stability 1. General To clarify the refferal criteria of intact stability Section 2. Material B. Hull Structural Steel for Plates and Sections Table 2.2 Material classes and grades for ships in general To clarify new requirements of material classes and grades for ships Table 2.3 Minimum material grades for ships excludingliquefiedgascarrierscoveredin Table 2.4, with length exceeding 150m and single strength deck To assert the definition of strength deck plate Table 2.4 Minimum Material Grades for membrane type liquefied gas carriers with length exceeding 150m Newly added Fig. 2.1 Typical deck arrangement for membrane type Liquefied Natural Gas Carriers Newly added 3.2 Material selection for longitudinal structural members To clarify minimum grade for sternframes supporting the rudder and propeller boss, rudders, rudder horns and shaft brackets 3.3 Material selection for local structural members To clarify the definition of requirements Section 21. Hull Outfit E. AirPipes, Overflow Pipes, Sounding Pipes 5.3.1 Applied loading for air pipes, ventilator pipes and their closing devices To add new formula for velocity of water over the fore deck Section 24. Oil Tanker A. General 11 Aluminium paints To add permission for applied of aluminium painting BKI - Rules for Hull - 2014
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- 29. Section 1 - General, Definitions A 1-1/10 Section 1 General, Definitions Note Passages printed in italics generally contain recommendations and notes which are not part of the Classification Rules. Requirements quoted in extracts of statutory regulations, which are mandatory besides Classification, may also be printed in italics. A. Validity, Equivalence 1. The Rules apply to seagoing steel ships classed A 100 whose breadth to depth ratio is within the range common for seagoing ships and the depth H of which is not less than: L/16 for Unlimited Range of Service and P (Restricted Ocean Service) L/18 for L (Coasting Service) L/19 for T (Sheltered Shallow Water Service). Smaller depths may be accepted if proof is submitted of equal strength, rigidity and safety of the ship. Hull structural design of bulk carriers with L $ 90 m contracted for construction on or after 1st April 2006, is to be carried out on the basis of the IACS Common Structural Rules for Bulk Carriers. For bulk carriers not subject to the IACS Common Structural Rules the requirements in Section 23, are applicable. Accordingly for double hull oil tankers with L $ 150 m the IACS Common Structural Rules for Double Hull Oil Tankers are applicable from this date on. For these ships Section 24, A. is to be observed in addition. Further rules relevant for hull structural design not covered by the IACS Common Structural Rules are issued by BKI in special companion volumes as complementary Rules to both IACS Common Structural Rules. For bulk carriers and oil tankers below each individual length limit these BKI Rules continue to apply under particular consideration of Section 23 and Section 24. 2. Ships deviating from the Construction Rules in their types, equipment or in some of their parts may be classed, provided that their structures or equipment is found to be equivalent to BKI’s requirements for the respective class. 3. For Characters of Classification and Class Notations see Rules for Classification and Survey, Volume I, Section 2. 4. For ships suitable for in-water surveys which will be assigned the Class Notation “IW”, the requirements of Section 37, are to be observed. 5. Class Notations for ships subject to extended strength analysis RSD Cargo hold analysis carried out by the designer and examined by BKI RSD (F25) Fatigue assessment based on 6,25 · 107 load cycles of North Atlantic Spectrum carried out by BKI RSD (F30) Fatigue assessment based on 7,5 · 107 load cycles of North Atlantic Spectrum carried out by BKI Fatigue assessment will be carried out for all hatch opening corners on all deck levels, longitudinal frames and butt welds of deck plating and side shell plating (where applicable). RSD (ACM) Additional corrosion margin according to detailed listings in the technical file. Analysis carried out by BKI. RSD (gFE) Global finite element analysis carried out in accordance with the Guidelines for Global Strength Analysis of Container Ships. BKI - Rules for Hull - 2014
- 30. B, C, D, E Section 1 - General, Definitions1-2/10 B. Restricted Service Ranges 1. For determining the scantlings of the longitudinal and transverse structures of ships intended to operate within one of the restricted service ranges P, L and T, the dynamic loads may be reduced as specified in Sections 4 and 5. 2. For the definition of the restricted service ranges P, L and T see Rules for Classification and Surveys, Volume I, Section 2,.C.3.1, Table 2.5 C. Ships for Special Services When a ship is intended to carry special cargoes (e.g. logs) the loading, stowage and discharging of which may cause considerable stressing of structures in way of the cargo holds, such structures are to be investigated for their ability to withstand these loads. D. Accessibility 1. All parts of the hull are to be accessible for survey and maintenance. 2. For safe access to the cargo area of oil tanker and bulk carriers see Section 21, N. E. Stability 1. General Ships with a length of 24 m and above will be assigned class only after it has been demonstrated that their intact stability is adequate for the service intended. Adequate intact stability means compliance with standards laid down by the relevant Administration. BKI reserves the right to deviate there from, if required for special reasons, taking into account the ships' size and type. The level of intact stability for ships of all sizes in any case should not be less than that provided by IMO-Resolution 267(85) (Adoption of the international code on intact stability, 2008 (2008 IS Code)), unless special operational restrictions reflected in the Class Notation render this possible. Part.B Chapter 2.3 of the above Resolution has only to be taken into account on special advice of the competent Administration. However, a preliminary stability information booklet approved by the Society in lieu of a final stability information booklet may be provided on-board for a specific period. Special attention is to be paid to the effect of free surfaces of liquids in partly filled tanks. Special precautions shall be taken for tanks which, due to the geometry, may have excessive free surface moments, thus jeopardizing the initial stability of the vessel, e.g. tanks in the double bottom reaching from side to side. In general such tanks shall be avoided. Evidence of approval by the competent Administration concerned may be accepted for the purpose of classification. The above provisions do not affect any intact stability requirements resulting from damage stability calculations, e.g. for ships to which the symbol is assigned. 2. Ships with proven damage stability Ships with proven damage stability will be assigned the symbol . In the Register and in an appendix to the Certificate the proof of damage stability will be specified by a code as detailed in Rules for Classification and Surveys, Volume I, Section 2, C.2.1, Table 2.2 2.1 Damage stability requirements applicable to bulk carriers 2.1.1 Bulk carriers of 150 min length and upwards of single side skin construction, designed to carry solid bulk cargoes having a density of 1000 kg/m3 and above shall, when loaded to the summer load line, be able to withstand flooding of any one cargo hold in all loading conditions and remain afloat in a satisfactory condition of equilibrium, as specified in the next 2.1.2. BKI - Rules for Hull - 2014
- 31. Section 1 - General, Definitions E, F 1-3/10 Subject to the provisions of that paragraph, the condition of equilibrium after flooding shall satisfy the condition of equilibrium laid down in the annex to resolution A.320(IX), Regulation equivalent to regulation 27 of the International Convention on Load Lines, 1966, as amended by resolution A.514(13). The assumed flooding need only take into account flooding of the cargo hold space. The permeability of a loaded hold shall be assumed as 0,9 and the permeability of an empty hold shall be assumed as 0,95, unless a permeability relevant to a particular cargo is assumed for the volume of a flooded hold occupied by cargo and a permeability of 0,95 is assumed for the remaining empty volume of the hold. Bulk carriers which have been assigned a reduced freeboard in compliance with the provisions of paragraph (8) of the regulationequivalenttoregulation27oftheInternationalConvention on Load Lines, 1966, adopted by resolution A.320(IC), as amended by resolution A.514(13), may be considered as complying with paragraphs 2.1.1. 2.1.2 On bulk carriers which have been assigned reduced freeboard in compliance with the provisions of regulation 27(8) set out in Annex B of the Protocol of 1988 relating to the International Convention on Load Lines, 1966, the condition of equilibrium after flooding shall satisfy the relevant provisions of that Protocol. 2.1.3 Ships with assigned reduced freeboards intended to carry deck cargo shall be provided with a limiting GM or KG curve required by SOLAS Chapter II-1, Regulation 25-8, based on compliance with the probabilistic damage stability analysis of Part B-1 (see IACS Unified Interpretation LL 65). 3. Anti-heeling devices 3.1 If tanks are used as anti-heeling devices, effects of maximum possible tank moments on intact stability are to be checked. A respective proof has to be carried out for several draughts and taking maximum allowable centres of gravity resulting from the stability limit curve as a basis. In general the heeling angle shall not be more than 10°. 3.2 If the ship heels more than 10°, Rules for Machinery Installations, Volume III, Section 11, P.1.4 has to be observed. 3.3 All devices have to comply with Rules for Electrical Installations, Volume IV, Section 7, G. F. Vibrations and Noise Notes 1. Mechanical vibrations Operating conditions which are encountered most frequently should be kept free as far as possible from resonance vibrations of the ship hull and individual structural components. Therefore, the exciting forces coming from the propulsion plant and pressure fluctuations should be limited as far as possible. Beside the selection of the propulsion units particular attention is to be given to the ship's lines including the stern post, as well as to the minimization of possible cavitation. In the shaping of the bow of large ships, consideration is to be given to limit excitation from the seaway. As far as critical excitation loads cannot be eliminated, appropriate measures are to be taken on the basis of theoretical investigations at an early design stage. Fatigue considerations mustbe included. For machinery, equipmentandother installations the vibration level is to be kept below that specified in Rules for Machinery Installations, Volume III, Section 1, as far as possible. The evaluation of vibrations in living and working areas should follow ISO 6954 except where other national or international rules or standards are mandatory. It is recommended to use the lower transition curve of ISO 6954 as a criteria for design, whereas the upper curve may serve for the evaluation of vibration measurements. 2. Noise Suitable precautions are to be taken to keep noises as low as possible particularly in the crew's quarters, working spaces, passengers' accommodations etc. Attention is drawn to regulations concerning noise level limitations, if any, of the flag administration. BKI - Rules for Hull - 2014
- 32. G Section 1 - General, Definitions1-4/10 G. Documents for Approval 1. To ensure conformity with the Rules the following drawings and documents are to be submitted in triplicate1)2) showing the arrangement and the scantlings of structural members : 1.1 Midship section The cross sectional plans (midship section, other typical sections) shall contain all necessary data on the scantlings of the longitudinal and transverse hull structure as well as details of anchor and mooring equipment. 1.2 Longitudinal section The plan of longitudinal sections shall contain all necessary details on the scantlings of the longitudinal and transverse hull structure and on the location of the watertight bulkheads and the deck supporting structures arrangement of superstructures and deck houses, as well as supporting structures of cargo masts, cranes etc. 1.3 Decks Plans of the decks showing the scantlings of the deck structures, length and breadth of cargo hatches, openings above the engine and boiler room, and other deck openings. On each deck, it has to be stated which deck load caused by cargo is to be assumed in determining the scantlings of the decks and their supports. Furthermore, details on possible loads caused by fork lift trucks and containers are to be stated. 1.4 Shell Drawings of shell expansion, containing full details on the location and size of the openings and drawings of the sea chests. 1.5 Ice strengthening The drawings listed in 1.1 - 1.4, 1.6, 1.7 and 1.9 shall contain all necessary details on ice strengthening. 1.6 Bulkheads Drawings of the transverse, longitudinal and wash bulkheads and of all tank boundaries, with details on densities of liquids, heights of overflow pipes and set pressures of the pressure-vacuum relief valves (if any). 1.7 Bottom structure 1.7.1 Drawings of single and double bottom showing the arrangement of the transverse and longitudinal girders as well as the water and oiltight subdivision of the double bottom. For bulk and ore carriers, data are to be stated on the maximum load on the inner bottom. 1.7.2 Docking plan and docking calculation according to Section 8, D. are to be submitted for information. 1.8 Engine and boiler seatings Drawings of the engine and boiler seatings, the bottom structure under the seatings and of the transverse structures in the engine room, with details on fastening of the engine foundation plate to the seating, as well as type and output of engine. 1.9 Stem and stern post, and rudder Drawings of stem and stern post, of rudder, including rudder support. The rudder drawings shall contain details on the ship's speed, the bearing materials to be employed, and the ice strengthening. Drawings of propeller brackets and shaft exits. 1.10 Hatchways Drawings of hatchway construction and hatch covers. The drawings of the hatch coamings shall contain all details, e.g., bearing pads with all relevant details regarding loads and substructures, including cut-outs for the fitting of equipment such as stoppers, securing devices etc. necessary for the 1) A detailed list of documents to be submitted for approval will be provided upon request. 2) For Indonesian flagships in quadruplicate (one for Indonesian Government). BKI - Rules for Hull - 2014
- 33. Section 1 - General, Definitions G 1-5/10 operation of hatches. The structural arrangement of stays and stiffeners and of their substructures shall be shown. 1.11 Longitudinal strength All necessary documents for the calculation of bending moments, shear forces and, if necessary, torsional moments. This includes the mass distribution for the envisaged loading conditions and the distribution of section moduli and moduli of inertia over the ship's length. Loading Guidance Information according to Section 5, A.4. 1.12 Materials The drawings mentioned in 1.l n 1.10 and 1.15 shall contain details on the hull materials (e.g. hull structural steel grades, standards, material numbers). Where higher tensile steels or materials other than ordinary hull structural steels are used, drawings for possible repairs have to be placed on board. 1.13 Weld joints The drawings listed in items 1.1 n 1.10 and 1.15 shall contain details on the welded joints e.g. weld shapes and dimensions and weld quality. For the relevant data for manufacturing and testing of welded joints see Rules for Welding, Volume VI. 1.14 Lashing and stowage devices Drawings containing details on stowage and lashing of cargo (e.g. containers, car decks). In the drawings the location of the connections and the appropriate substructures at the ship shall be shown in detail. 1.15 Substructures Drawings of substructures below steering gears, windlasses and chain stoppers as well as masts and boat davits together with details on loads to be transmitted into structural elements. 1.16 Closing condition For assessing the closing condition. details on closing appliances of all openings on the open deck in position 1 and 2 according to ICLL and in the shell, i e. hatchways, cargo ports, doors, windows and side scuttles, ventilators, erection openings, manholes, sanitary discharges and scuppers. 1.17 Watertight Integrity Drawings containing the main- and local internal subdivision of the hull. Information about arrangements of watertight longitudinal- and transverse bulkheads, cargo hold entrances, air ventilation ducts, down- and crossflooding arrangements. 1.18 Intact stability Analysis of an inclining experiment to be performed upon completion of newbuildings and/or conversions, for determining the light ship data. Intact stability particulars containing all information required for calculation of stability in different loading conditions. For initial assignment of class to new buildings preliminary particulars will be acceptable. 1.19 Damage stability Damage stability particulars containing all information required for establishing unequivocal condition for intact stability. A damage control plan with details on watertight subdivision, closable openings in watertight bulkheads as well as cross flooding arrangements and discharge openings. 1.20 Structural fire protection In addition to the fire control and safety plan also drawings of the arrangement of divisions (insulation, A-, B- and C-divisions) including information regarding BKI-approval number. Drawings of air conditioning and ventilation plants. 1.21 Special particulars for examination 1.21.1 For ships constructed for special purposes, drawings and particulars of those parts, examination of which is BKI - Rules for Hull - 2014
- 34. G, H Section 1 - General, Definitions1-6/10 necessary for judging the vessel's strength and safety. 1.21.2 Additional documents and drawings may be required, if deemed necessary. 1.21.3 Any deviations from approved drawings are subject to approval before work is commenced. H. Definitions 1. General Unless otherwise mentioned, the dimensions according to 2. and 3. are to be inserted [m] into the formulae stated in the following Sections. 2. Principal dimensions 2.1 Length L The length L is the distance in metres, on the summer load waterline from the foreside of stem to the after side of the rudder post, or the centre of the rudder stock if there is no rudder post. L is not to be less than 96% and need not be greater than 97% of the extreme length of the summer load waterline. In ships with unusual stern and bow arrangement, the length L will be specially considered. 2.2 Length Lc (according to ICLL, MARPOL 73/ 78, IBC - Code and IGC - Code ) The length Lc is to be taken as 96 % of the total length on a waterline at 85 % of the least moulded depth Hc measured from the top of the keel, or as the length from the fore side of the stem to the axis of the rudder stock on that waterline, if that be greater. In ships designed with a rake of keel the waterline on which this length is measured shall be parallel to the designed waterline. For the definition of the least moulded depth Hc see ICLL, Annex I, Chapter I, Regulation 3 (5). 2.3 Length L* (according to SOLAS 74 Chapter II-1, Reg 2) The length L* of the ship is the length measured between perpendiculars taken at the extremities of the deepest subdivision load line. 2.4 Subdivision length Ls Reference is made to the definition in SOLAS 74, Chapter II–1, Reg. 25 – 2.2.1 and in Section 36, B.4. 2.5 Forward perpendicular FP. The forward perpendicular coincides with the foreside of the stem on the waterline on which the respective length L, Lc, or L* is measured. 2.6 Breadth B The breadth B is the greatest moulded breadth of the ship. 2.7 Depth H The depth H is the vertical distance, at the middle of the length L, from the base line3) to top of the deck beam at side on the uppermost continuous deck. In way of effective superstructures the depth H is to be measured up to the superstructure deck for determining the ship's scantlings. 2.8 Draught T The draught T is the vertical distance at the middle of the length L from base line to freeboard marking for summer load waterline. Fo r ships with timber load line the draught T is to be measured up to the freeboard mark for timber load waterline. 3) Base line is a line passing trough top of the keel plate at the middle of the length L. BKI - Rules for Hull - 2014
- 35. Section 1 - General, Definitions H, J 1-7/10 3. Frame spacing a The frame spacing a will be measured from moulding edge to moulding edge of frame. 4. Block coefficient CB Moulded block coefficient at load draught T, based on length L. 5. Ship's speed v0 Maximum service speed [kn], which the ship is designed to maintain at the summer load line draught and at the propeller RPM corresponding to MCR (maximum continuous rating). In case of controllable pitch propellers the speed v0 is to be determined on the basis of maximum pitch. 6. Definition of decks 6.1 Bulkhead deck Bulkhead deck is the deck up to which the watertight bulkheads are carried. 6.2 Freeboard deck Freeboard deck is the deck upon which the freeboard calculation is based. 6.3 Strength deck Strength deck is the deck or the parts of a deck which form the upper flange of the effective longitudinal structure. 6.4 Weather deck All free decks and parts of decks exposed to the sea are defined as weather deck. 6.5 Lower decks Starting from the first deck below the uppermost continuous deck, the lower decks are defined as 2nd , 3rd deck, etc. 6.6 Superstructure decks Thesuperstructuredeckssituatedimmediatelyabovetheuppermost continuous deck are termed forecastle deck, bridge deck, and poop deck. Superstructure decks above the bridge deck are termed 2nd, 3rd superstructure deck, etc. 6.7 Positions of Hatchways, doorways and ventilators For the arrangement of hatches, doors and ventilators the following areas are defined: Pos. 1 S on exposed freeboard decks, S on raised quarter decks, S on the first exposed superstructure deck above the freeboard deck within the forward quarter of Lc. Pos. 2 S on exposed superstructure decks aft of the forward quarter of Lc located at least one standard height of superstructure above the freeboard deck S on exposed superstructure decks within the forward quarter of Lc located at least two standard heights of superstructure above the freeboard deck J. International Conventions and Codes Where reference is made of International Conventions and Codes these are defined as follows: 1. ICLL International Convention on Load Lines, 1966 as amended. BKI - Rules for Hull - 2014
- 36. J, K, L, M Section 1 - General, Definitions1-8/10 2. MARPOL 73/78 International Convention for the Prevention of Pollution from Ships, 1973 including the 1978 Protocol as amended. 3. SOLAS 74 International Convention for the Safety of Life at Sea, 1974 as amended. 4. IBC-Code International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk as amended. 5. IGC-Code International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk as amended. K. Rounding-off Tolerances Where in determining plate thicknesses in accordance with the provisions of the following Sections the figures differ from full or half mm, they may be rounded off to full or half millimeters up to 0,2 or 0,7; above 0,2 or 0,7 mm they are to be rounded up. If plate thicknesses are not rounded the calculated required thicknesses shall be shown in the drawings. The section moduli of profiles usual in the trade and including the effective width according to Section 3, E. and F. may be 3 % less than the required values according to the following Rules for dimensioning. L. Regulations of National Administrations For the convenience of the user of these Rules several Sections contain for guidance references to such regulations of National Administrations, which deviate from the respective rule requirements of this Society but which may have effect on scantlings and construction. These references have been specially marked. Compliance with these Regulations of National Administrations is not conditional for class assignment. M. Computer Programs 1. General 1.1 In order to increase the flexibility in the structural design of ships BKI also accepts direct calculations with computer programs. The aim of such analyses should be the proof of equivalence of a design with the rule requirements. 1.2 Direct calculations may also be used in order to optimize a design; in this case only the final results are to be submitted for examination. 2. General Programs 2.1 The choice of computer programs according to "State of the Art" is free. The programs may be checked by BKI through comparative calculations with predefined test examples. A generally valid approval for a computer program is, however, not given by BKI. 2.2 Direct calculations may be used in the following fields: S longitudinal strength, S beams and grillages, S detailed strength, S global strength. 2.3 For such calculation the computer model, the boundary condition and load cases are to be agreed upon with BKI. BKI - Rules for Hull - 2014
- 37. Section 1 - General, Definitions M, N 1-9/10 The calculation documents are to be submitted including input and output. During the examination it may prove necessary that BKI perform independent comparative calculations. 2.4 Collision resistance Calculation of the structure's resistance against collision for granting the additional Class Notation ”COLL” according to Section 35. N. Workmanship 1. General 1.l Requirements to be complied with by the manufacturer 1.1.1The manufacturing plant Shall be provided with suitable equipment and facilities to enable proper handling of the materials, manufacturing processes, structural components, etc. BKI reserve the right to inspect the plant accordingly or to restrict the scope of manufacture to the potential available at the plant. 1.1.2The manufacturing plant shall have at its disposal sufficiently qualified personnel. BKI is to be advised of the names and areas of responsibility of all supervisory and control personnel. BKI reserves the right to require proof of qualification. 1.2 Quality control 1.2.1As far as required and expedient, the manufacturer's personnel has to examine all structural components both during manufacture and on completion, to ensure that they are complete, that the dimensions are correct and that workmanship is satisfactory and meets the standard of good shipbuilding practice. 1.2.2Upon inspection and corrections by the manufacturing plant, the structural components are to be shown to the BKI Surveyor for inspection, in suitable Sections, normally in unpainted condition and enabling proper access for inspection. 1.2.3The Surveyor may reject components that have not been adequately checked by the plant and may demand their re-submission upon successful completion of such checks and corrections by the plant. 2. Structural details 2.1 Details in manufacturing documents 2.1.1All significant details concerning quality and functional ability of the component concerned shall be entered in the manufacturing documents (workshop drawings etc.). This includes not only scantlings but - where relevant - such items as surface conditions (e.g. finishing of flame cut edges and weld seams), and special methods of manufacture involved as well as inspection and acceptance requirements and where relevant permissible tolerances. So far as for this aim a standard shall be used (works or national standard etc.) it shall be harmonized with BKI. This standard shall be based on the IACS Recommendation 47 Shipbuilding and Repair Quality Standard for New Construction. For weld joint details, see Section 19, A.1. 2.1.2If, due to missing or insufficient details in the manufacturing documents, the quality or functional ability of the component cannot be guaranteed or is doubtful, BKI may require appropriate improvements. This includes the provision of supplementary or additional parts (for example reinforcements) even if these were not required at the time of plan approval or if - as a result of insufficient detailing- such requirement was not obvious. 2.2 Cut-outs, plate edges 2.2.1The free edges (cut surfaces) of cut-outs, hatch corners, etc. are to be properly prepared and are to be free from notches. As a general rule, cutting drag lines etc. shall not be welded out, but are to be smoothly ground. All edges should be broken or in cases of highly stressed parts, should be rounded off. 2.2.2Free edges on flame or machine cut plates or flanges are not to be sharp cornered and are to be finished off as laid down in 2.2.1 This also applies to cutting drag lines etc., in particular to the upper edge of sheer strake and analogously to weld joints, changes in sectional areas or similar discontinuities. BKI - Rules for Hull - 2014
- 38. N Section 1 - General, Definitions1-10/10 2.3 Cold forming 2.3.1For cold forming (bending, flanging, beading) of plates the minimum average bending radius shall not fall short of 3@t (t = plate thickness) and shall be at least 2@t. Regarding the welding of cold formed areas, see Section.19, B.2.6. 2.3.2In order to prevent cracking, flame cutting flash or shearing burrs shall be removed before cold forming. After cold forming all structural components and, in particular, the ends of bends (plate edges) are to be examined for cracks. Except in cases where edge cracks are negligible, all cracked components are to be rejected. Repair welding is not permissible. 2.4 Assembly, alignment 2.4.1 The use of excessive force is to be avoided during the assembly of individual structural components or during the erection of sections. As far as possible major distortions of individual structural components should be corrected before further assembly. 2.4.2 Girders, beams, stiffeners, frames etc. that are interrupted by bulkheads, decks etc. shall be accurately aligned. In the case of critical components, control drillings are to be made where necessary, which are then to be welded up again on completion. 2.4.3 After completion of welding, straightening and aligning shall be carried out in such a manner that the material properties will not be influenced significantly. In case of doubt, BKI may require a procedure test or a working test to be carried out. 3. Corrosion protection For corrosion protection, see Section 38. BKI - Rules for Hull - 2014
- 39. Section 2 - Materials A, B 2-1/10 Section 2 Materials A. General All materials to be used for the structural members indicated in the Construction Rules are to be in accordance with the Rules for Materials, Volume V. Materials the properties of which deviate from these Rule requirements may only be used upon special approval. B. Hull Structural Steel for Plates and Sections 1. Normal strength hull structural steel 1.1 Normal strength hull structural steel is a hull structural steel with a minimum nominal upper yield point ReH of 235 N/mm2 and a tensile strength Rm of 400 - 520 N/mm2 , see also Section 17.A.3. 1.2 The material factor k in the formulae of the following Sections is to be taken 1,0 for normal strength hull structural steel. 1.3 Normal strength hull structural steel is grouped into the grades KI-A, KI-B, KI-D, KI-E, which differ from each other in their toughness properties. For the application of the individual grades for the hull structural members, see 3. 1.4 If for special structures the use of steels with yield properties less than 235 N/mm2 has been accepted, the material factor k is to be determined by : 2. Higher strength hull structural steels 2.1 Higher strength hull structural steel is a hull structural steel, the yield and tensile properties of which exceed those of normal strength hull structural steel. According to the Rules for Materials, Volume V, for three groups of higher strength hull structural steels the nominal upper yield stress ReH has been fixed at 315, 355 and 390 N/mm2 respectively. Where higher strength hull structural steel is used, for scantling purposes the values in Table 2.1 are to be used for the material factor k mentioned in the various Sections. For higher strength hull structural steel with other nominal yield stresses up to 390 N/mm2 , the material factor k may be determined by the following formula: Note Especially when higher strength hull structural steels are used, limitation of permissible stresses due to buckling and fatigue strength criteria may be required. Table 2.1 Material factor k ReH [N/mm2 ] k 315 355 390 0,78 0,72 0,66 2.2 Higher strength hull structural steel is grouped into the following grades, which differ from each other in their toughness properties : KI-A 32/36/40 BKI - Rules for Hull - 2014
- 40. B Section 2 - Materials2-2/10 KI-D 32/36/40 KI-E 32/36/40 KI-F 32/36/40. In Table 2.8 the grades of the higher strength hull structural steels are marked by the letter "H". 2.3 Where structural members are completely or partly made from higher strength hull structural steel, a suitable Notation will be entered into the Ship's Certificate. 2.4 In the drawings submitted for approval it is to be shown which structural members are made of higher strength hull structural steel. These drawings are to be placed on board in case any repairs are to be carried out. 2.5 Regarding welding of higher strength hull structural steel, see Rules for Welding, Volume VI, Section 12. 3. Material selection for the hull 3.1 Material classes For the material selection for hull structural members material classes as given in Table 2.2 are defined. BKI - Rules for Hull - 2014
- 41. Section 2 - Materials B 2-3/10 Table 2.2 - Material classes and grades for ships in general Structural member category Material class or grade Secondary : A1. Longitudinal bulkhead strakes, other than that belonging to the Primary category A2. Deck plating exposed to weather, other than that belonging to the Primary or Special category A3. Side plating S Class I within 0,4 L amidships S Grade A/AH outside 0,4 L amidships Primary : B1. Bottom plating, including keel plate B2. Strength deck plating, excluding that belonging to the Special category B3. Continuous longitudinal plating of strength members above strength deck, excluding hatch coamings B4. Uppermost strake in longitudinal bulkhead B5. Vertical strake (hatch side girder) and uppermost sloped strake in top wing tank S Class II within 0,4 L amidships S Grade A/AH outside 0,4 L amidships Special : C1. Sheer strake at strength deck 1) C2. Stringer plate in strength deck 1) C3. Deck strake at longitudinal bulkhead excluding deck plating in way of inner-skin bulkhead of double-hull ships 1) S Class III within 0,4 L amidships S Class II outside 0,4 L amidships S Class I outside 0,6 L amidships C4. Strength deck plating at outboard corners of cargo hatch openings in container ships and other ships with similar hatch openings configurations S Class III within 0,4 L amidships S Class II outside 0,4 L amidships S Class I outside 0,6 L amidships S Min. Class III within cargo region C5. Strength deck plating at corners of cargo hatch openings in bulk carriers, ore carriers, combination carriers and other ships with similar hatch openings configurations C5.1 Trunk deck and inner deck plating at corners of openings for liquid and gas domes in membrane type liquefied gas carriers S Class III within 0,6 L amidships S Class II within rest of cargo region C6. Bilge strake in ships with double bottom over the full breadth and length less than 150 m 1) S Class II within 0,6 L amidships S Class I outside 0,6 L amidships C7. Bilge strake in other ships 1) S Class III within 0,4 L amidships S Class II outside 0,4 L amidships S Class I outside 0,6 L amidships C8. Longitudinal hatch coamings of length greater than 0,15 L including coaming top plate and flange C9. End brackets and deck house transition of longitudinal cargo hatch coamings S Class III within 0,4 L amidships S Class II outside 0,4 L amidships S Class I outside 0,6 L amidships S Not to be less than grade D/DH 1) Single strakes required to be of class III within 0,4 L amidships are to have breadths not less than 800 + 5 L [mm] need not be grater than 1800 mm, unless limited by the geometry of the ship's design. BKI - Rules for Hull - 2014
- 42. B Section 2 - Materials2-4/10 Table 2.3 - Minimum material grades for ships, excluding liquefied gas carriers covered in Table 2.4, with length exceeding 150 m and single strength deck Structural member category Material grade ! Longitudinal plating of strength deck where contributing to the longitudinal strength ! Continuous longitudinal plating of strength members above strength deck Grade B/AH within 0,4 L amidships Single side strakes for ships without inner continuous longitudinal bulkhead(s) between bottom and the strength deck Grade B/AH within cargo region Table 2.4 - Minimum Material Grades for membrane type liquefied gas carriers with length exceeding 150 m * Structural member category Material grade Longitudinal plating of strength deck where contributing to the longitudinal strength Grade B/AH within 0.4L amidships Continuous longitudinal plating of strength members above the strength deck Trunk deck plating Class II within 0.4L amidships ! Inner deck plating ! Longitudinal strength member plating between the trunk deck and inner deck Grade B/AH within 0.4L amidships (*) Table 2.4 is applicable to membrane type liquefied gas carriers with deck arrangements as shown in Fig.2.1. Table 2.4 may apply to similar ship types with a “double deck” arrangement above the strength deck. Fig. 2.1 Typical deck arrangement for membrane type Liquefied Natural Gas Carriers BKI - Rules for Hull - 2014
- 43. Section 2 - Materials B 2-5/10 Table 2.5 - Minimum material grades for ships with length exceeding 250 m Structural member category Material grade Shear strake at strength deck 1) Grade E/EH within 0,4 L amidships Stringer plate in strength deck 1) Grade E/EH within 0,4 L amidships Bilge strake 1) Grade D/DH within 0,4 L amidships 1) Single strakes required to be of Grade E/EH and within 0,4 L amidships are to have breadths not less than 800 + 5 L [mm], need not be grater than 1800 mm, unless limited by the geometry of the ship's design. Table 2.6 - Minimum material grades for single-side skin bulk carriers subjected to SOLAS regulation XII/6.5.3 Structural member category Material grade Lower bracket of ordinary side frame 1), 2) Grade D/DH Side shell strakes included totally or partially between the two points located to 0,125 R above and below the intersection of side shell and bilge hopper sloping plate or inner bottom plate2) Grade D/DH 1) The term "lower bracket" means webs of lower brackets and webs of the lower part of side frames up to the point of 0,125 R above the intersection of side shell and bilge hopper sloping plate or inner bottom plate. 2) The span of the side frame R is defined as the distance between the supporting structures. Table 2.7 - Minimum material grades for ships with ice strengthening Structural member category Material grade Shell strakes in way of ice strengthening area for plates Grade B/AH Table 2.8 - Steel grades to be used, depending on plate thickness and material class Thickness t [mm] 1) > 15 > 20 > 25 > 30 > 35 > 40 > 50 Material class # 15 # 20 # 25 # 30 # 35 # 40 # 50 # 1003) I A/AH A/AH A/AH A/AH B/AH B/AH D/DH D/DH2) II A/AH A/AH B/AH D/DH D/DH 4) D/DH 4) E/EH E/EH III A/AH B/AH D/DH D/DH 4) E/EH E/EH E/EH E/EH 1) Actual thickness of the structural member. 2) For thicknesses t > 60 mm E/EH. 3) For thicknesses t > 100 mm the steel grade is to be agreed with BKI. 4) For nominal yield stresses ReH $ 390 N/mm2 EH. 3.2 Material selection for longitudinal structural members Materials in the various strength members are not to be of lower grades than those corresponding to the material classes and grades specified in Table 2.2 to Table 2.8. General requirements are given in Table 2.2, while additional minimum requirements are given in the following: Table 2.3: for ships, excluding liquefied gas carriers covered in Table 3, with length exceeding 150 m and single strength deck, Table 2.4: for membrane type liquefied gas carriers with length exceeding 150 m, Table 2.5: for ships with length exceeding 250 m, Table 2.6: for single side bulk carriers subjected to SOLAS regulation XII/6.5.3, Table 2.7: for ships with ice strengthening. The material grade requirements for hull members of each class depending on the thickness are defined in Table 2.8. For strength members not mentioned in Tables 2.2 to 2.7, Grade A/AH may generally be used. The steel grade is to correspond to the as-built plate thickness and material class. Plating materials for sternframes supporting the rudder and propeller boss, rudders, rudder horns and shaft brackets are BKI - Rules for Hull - 2014
- 44. B Section 2 - Materials2-6/10 in general not to be of lower grades than corresponding to Class II. 3.3 Material selection for local structural members 3.3.1 The material selection for local structural members, which are not part of the longitudinal hull structure, may in general be effected according to Table 2.9. For parts made of forged steel or cast steel C. is to be applied. Table 2.9 - Material selection for local structural members Structural member Material class hawse pipe, stern tube, pipe stanchion3) I face plates and webs of girder systems, hatch cover II1) rudder body 2) , rudder horn, sole piece, stern frame, propeller brackets, trunk pipe II 1) Class I material sufficient, where rolled sections are used or the parts are machine cut from plates with condition on delivery of either "normalized", "rolled normalized" or "rolled thermo- mechanical". 2) See 3.3.2 3) For pipe stanchions for cargo reefer holds Table 2.10 is applicable. 3.3.2 For rudder and rudder body plates subjected to stress concentrations (e.g. in way of lower support of semi- spade rudders or at upper part of spade rudders) Class III is to be applied. 3.3.3 For top plates of machinery foundations located outside 0,6 L amidships, grade A ordinary hull structural steel may also be used for thicknesses above 40 mm. For members not specifically mentioned normally grade A/AH may be used. However, BKI may require also higher grades depending on the stress level. 3.4 Material selection for structural members which are exposed to low temperatures 3.4.1 The material selection for structural members, which are continuously exposed to temperatures below 0 °C, e.g. in or adjacent to refrigerated cargo holds, is governed by the design temperature of the structural members. The design temperature is the temperature determined by means of a temperature distribution calculation taking into account the design environmental temperatures. The design environmental temperatures for unrestricted service are: air : + 5° C sea water : 0° C. 3.4.2 For ships intended to operate permanently in areas with low air temperatures (below and including - 20 °C), e.g. regular service during winter seasons to Arctic or Antarctic waters, the materials in exposed structures are to be selected based on the design temperature tD , to be taken as defined in 3.4.5. Materials in the various strength members above the lowest ballast waterline (BWL) exposed to air are not to be of lower grades than those corresponding to classes I, II and III, as given in Table 2.10, depending on the categories of structural members (Secondary, Primary and Special). For non-exposed structures and structures below the lowest ballast waterline, see 3.2 and 3.3. 3.4.3 The material grade requirements of each material class depending on thickness and design temperature are defined in Table 2.11. For design temperatures tD < - 55 °C, materials are to be specially considered. 3.4.4 Single strakes required to be of class III or of grade E/EH or FH are to have breadths not less 800 + 5 × L [mm], maximum 1800 mm. Plating materials for stern frames, rudder horns, rudders and shaft brackets are not to be of lower grades than those corresponding to the material classes given in 3.3. 3.4.5 The design temperature tD is to be taken as the lowest mean daily average air temperature in the area of operation, see Fig. 2.2. The following definitions apply: BKI - Rules for Hull - 2014
- 45. Section 2 - Materials B,C,D 2-7/10 Mean : Statistical mean over an observation period of at least 20 years Average : Average during one day and night. Lowest : Lowest during the year. For seasonally restricted service the lowest expected value within the period of operation applies. 4. Structural members which are stressed in direction of their thickness In case of high local stresses in the thickness direction, e.g. due to shrinkage stresses in single bevel or double bevel T-joints with a large volume of weld metal, steels with guaranteed material properties in the thickness direction according to the Rules for Materials, Volume V, Section 4, I. are to be used. Fig. 2.2 Commonly used definitions of temperatures C. Forged Steel and Cast Steel Forged steel and cast steel for stem, stern frame, rudder post as well as other structural components, which are subject of this Rule, are to comply with the Rules for Materials, Volume V. The tensile strength of forged steel and of cast steel is not to be less than 400 N/mm2 . Forged steel and cast steel are to be selected under consideration of B.3. In this respect beside strength properties also toughness requirements and weldability shall be observed. D. Aluminium Alloys 1. Where aluminium alloys, suitable for seawater, as specified in the Rules for Materials, Volume V, are used for the construction of superstructures, deckhouses, hatchway covers and similar parts, the conversion from steel to aluminium scantlings is to be carried out by using the material factor : Rp0,2 = 0,2% proof stress of the aluminium alloy [N/mm2 ] Rm = tensile strength of the aluminium alloy [N/mm2 ] For welded connections the respective values in welded condition are to be taken. Where these figures are not available, BKI - Rules for Hull - 2014
- 46. D,E Section 2 - Materials2-8/10 the respective values for the soft-annealed condition are to be used. Method of conversion: – section modulus: WAR = WSt @ kAR – plate thickness: tAR = tSt @ 2. The smaller modulus of elasticity is to be taken into account when determining the buckling strength of structural elements subjected to compression. This is to be applied accordingly to structural elements for which maximum allowable deflections have to be adhered to. 3. The conversion of the scantlings of the main hull structural elements from steel into aluminium alloy is to be specially considered taking into account the smaller modulus of elasticity, as compared with steel, and the fatigue strength aspects, specifically those of the welded connections. E. Austenitic Steels Where austenitic steels are applied having a ratio Rp0,2/Rm 0,5, after special approval the 1% proof stress Rp1,0 may be used for scantling purposes instead of the 0,2% proof stress Rp0,2. BKI - Rules for Hull - 2014
- 47. Section 2 - Materials E 2-9/10 Table 2.10 - Material classes and grades for structures exposed to low temperatures Structural member category Material class Within 0,4 L amidships Outside 0,4 L amidships Secondary: Deck plating exposed to weather, in general Side plating above BWL 5) Transverse bulkheads above BWL 5) I I Primary: Strength deck plating 1) Continuous longitudinal members above strength deck, excluding longitudinal hatch coamings Longitudinal bulkhead above BWL 5) Top wing tank plating above BWL 5) II I Special: Sheer strake at strength deck 2) Stringer plate in strength deck 2) Deck strake at longitudinal bulkhead 3) Continuous longitudinal hatch coamings 4) III II 1) Plating at corners of large hatch openings to be specially considered. Class III or grade E/EH to be applied in positions where high local stresses may occur. 2) Not to be less than grade E/EH within 0,4 L amidships in ships with length exceeding 250 metres. 3) In ships with breadth exceeding 70 metres at least three deck strakes to be of class III. 4) Not to be less than grade D/DH 5) BWL = ballast waterline. BKI - Rules for Hull - 2014
- 48. E Section 2 - Materials2-10/10 Table 2.11 - Material grade requirements for classes I, II and III at low temperatures Class I Plate thickness [mm] tD tD tD tD – 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C normal strength higher strength normal strength higher strength normal strength higher strength normal strength higher strength t 10 A AH B AH D DH D DH 10 < t 15 B AH D DH D DH D DH 15 < t 20 B AH D DH D DH E EH 20 < t 25 D DH D DH D DH E EH 25 < t 30 D DH D DH E EH E EH 30 < t 35 D DH D DH E EH E EH 35 < t 45 D DH E EH E EH FH 45 < t 50 E EH E EH FH FH Class II Plate thickness [mm] tD tD tD tD – 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C normal strength higher strength normal strength higher strength normal strength higher strength normal strength higher strength t 10 B AH D DH D DH E EH 10 < t 20 D DH D DH E EH E EH 20 < t 30 D DH E EH E EH FH 30 < t 40 E EH E EH FH FH 40 < t 45 E EH FH FH 45 < t 50 E EH FH FH Class III Plate thickness [mm] tD tD tD tD – 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C normal strength higher strength normal strength higher strength normal strength higher strength normal strength higher strength t 10 D DH D DH E EH E EH 10 < t 20 D DH E EH E EH FH 20 < t 25 E EH E EH FH FH 25 < t 30 E EH E EH FH FH 30 < t 35 E EH FH FH 35 < t 40 E EH FH FH 40 < t 50 FH FH BKI - Rules for Hull - 2014
- 49. Section 3 - Design Principles A 3-1/24 Section 3 Design Principles A. General 1. Scope This Section contains definitions and general design crteria for hul structural elements as well as indications concerning structural details. 2. Permissible stresses and required sectional properties In the following Sections permissible stresses have been stated in addition to the formulae for calculating the section moduli and cross sectional areas of webs of frames, beams, girders, stiffeners etc. and may be used when determining the scantlings of those elements by means of direct strength calculations. The required section moduli and web areas are related on principle to an axis which is parallel to the connected plating. For profiles usual in the trade and connected vertically to the plating in general the appertaining sectional properties are given in tables. Where webs of stiffeners and girders are not fitted vertically to the plating (e.g. frames on the shell in the flaring fore body) the sectional properties (moment of inertia, section modulus and shear area) have to be determined for an axis which is parallel to the plating. For bulb profiles and flat bars the section modulus of the inclined profile including plating can be calculated simplified by multiplying the corresponding value for the vertically arranged profile by sin " where " is the smaller angle between web and attached plating. Note For bulb profiles and flat bars " in general needs only be taken into account where " is less than 75°. Furthermore, with asymmetric profiles where additional stresses occur according to L. the required section modulus is to be increased by the factor ksp depending on the type of profile, see L. 3. Plate panels subjected to lateral pressure The formulae for plate panels subjected to lateral pressure as given in the following Sections are based on the assumption of an uncurved plate panel having an aspect ratio b/a 2,24. For curved plate panels and/or plate panels having aspect ratios smaller than b/a = 2,24, the thickness may be reduced as follows: t = C = constant, e.g. C = 1,1 for tank plating f1 = f2 = r = radius of curvature a = smaller breadth of plate panel b = larger breadth of plate panel p = applicable design load. tK = corrosion addition according to K. The above does not apply to plate panels subjected to ice pressure according to Section 15 and to longitudinally framed side shell plating according to Section 6. BKI - Rules for Hull - 2014
- 50. A, B, C Section 3 - Design Pinciples3-2/24 4. Fatigue strength Where a fatigue strength analysis is required or will be carried out for structures or structural details this shall be in accordance with the requirements of Section 20. B. Upper and Lower Hull Flange 1. All continuous longitudinal structural members up to zo below the strength deck at side and up to zu above base line are considered to be the upper and lower hull flange respectively. 2. Where the upper and/or the lower hull flange are made from normal strength hull structural steel their vertical extent zo = zu equals 0,1 H. On ships with continuous longitudinal structural members above the strength deck a fictitious depth H' = eB + e'D is to be applied. eB = distance between neutral axis of the midship section and base line [m] e'D see Section 5, C.4.1 3. The vertical extent z of the upper and lower hull flange respectively made from higher tensile steel of one quality is not to be less than: z = e (1 S n @ k) e = distance of deck at side or of the base line from the neutral axis of the midship section. For ships with continuous longitudinal structural members above the strength deck, see Section 5, C.4.1 n = W(a) = actual deck or bottom section modulus W = rule deck or bottom section modulus. Where two different steel grades are used it has to be observed that at no point the stresses are higher than the permissible stresses according to Section 5, C.1. C. Unsupported Span 1. Stiffeners, frames The unsupported span R is the true length of the stiffeners between two supporting girders or else their length including end attachments (brackets). The frame spacings and spans are normally assumed to be measured in a vertical plane parallel to the centreline of the ship. However, if the ship's side deviates more than 10° from this plane, the frame distances and spans shall be measured along the side of the ship. Instead of the true length of curved frames the length of the chord between the supporting points can be selected. 2. Corrugated bulkhead elements The unsupported span R of corrugated bulkhead elements is their length between bottom or deck and their length between vertical or horizontal girders. Where corrugated bulkhead elements are connected to box type elements of comparatively low rigidity, their depth is to be included into the span R unless otherwise proved by calculations. 3. Transverses and girders The unsupported span R of transverses and girders is to be determined according to Fig. 3.1, depending on the type of end attachment. In special cases, the rigidity of the adjoining girders is to be taken into account when determining the span of girder. BKI - Rules for Hull - 2014
- 51. Section 3 - Design Pinciples D 3-3/24 Fig. 3.1 Unsupported span R D. End Attachments 1. Definitions For determining scantlings of beams, stiffeners and girders the terms "constraint" and "simple support" will be used. "Constraint" will be assumed where for instance the stiffeners are rigidly connected to other members by means of brackets or are running throughout over supporting girders. "Simple support" will be assumed where for instance the stiffener ends are sniped or the stiffeners are connected to plating only, see also 3. 2. Brackets 2.1 For the scantlings of brackets the required section modulus of the section is decisive. Where sections of different section moduli are connected to each other, the scantlings of the brackets are generally governed by the smaller section. 2.2 The thickness of brackets is not to be less than : t = c = 1,2 for non-flanged brackets = 0,95 for flanged brackets k1 = material factor k for the section according to Section 2, B.2. tK = corrosion addition according to K W = section modulus of smaller section [cm3 ] tmin = 5 + tK mm tmax = web thickness of smaller section. For minimum thicknesses in tanks and in cargo holds of bulk carriers see Section 12, A.7., Section 23, B.5.3 and Section 24, A.13. 2.3 The arm length of brackets is not to be less than: R = [mm] Rmin = 100 mm ct = ta = "as built" thickness of bracket [mm] > t according to 2.2 W = see 2.2 k2 = material factor k for the bracket according to Section 2, B.2. BKI - Rules for Hull - 2014
- 52. D, E Section 3 - Design Pinciples3-4/24 The arm length R is the length of the welded connection. Note For deviating arm length the thickness of brackets is to be estimated by direct calculations considering sufficient safety against buckling. 2.4 The throat thickness a of the welded connection is to be determined according to Section 19, C.2.7. 2.5 Where flanged brackets are used the width of flange is to be determined according to the following formulae: b = [mm] b is not to be taken less than 50 mm and need not be taken greater than 90 mm. 3. Sniped ends of stiffeners Stiffeners may be sniped at the ends, if the thickness of the plating supported by stiffeners is not less than: t = [mm] p = design load [kN/m2 ] R = unsupported length of stiffener [m] a = spacing of stiffeners [m] ReH = minimum nominal upper yield point of the plating material [N/mm2 ] according to Section 2, B.2 c = 15,8 for watertight bulkheads and for tank bulkheads when loaded by p2 according to Section 4, D.1.2 = 19,6 otherwise, 4. Corrugated bulkhead elements Care is to be taken that the forces acting at the supports of corrugated bulkheads are properly transmitted into the adjacent structure by fitting structural elements such as carlings, girders or floors in line with the corrugations. Note Where carlings or similar elements cannot be fitted in line with the web strips of corrugated bulkhead elements, these web strips cannot be included into the section modulus at the support point for transmitting the moment of constraint. Deviating from the formula stipulated in Section 11, B.4.3 the section modulus of a corrugated element is then to be determined by the following formulae: W = [cm3 ] E. Effective Breadth of Plating 1. Frames and stiffeners Generally, the spacing of frames and stiffeners may be taken as effective breadth of plating. 2. Girders 2.1 The effective breadth of plating “em” of frames and girders may be determined according to Table 3.1 considering the type of loading. Special calculations may be required for determining the effective breadth of one-sided or non-symmetrical flanges. 2.2 The effective cross sectional area of plates is not to be less than the cross sectional area of the face plate. BKI - Rules for Hull - 2014
- 53. Section 3 - Design Pinciples E, F 3-5/24 Table 3.1 Effective breadth em of frames and girders R/e 0 1 2 3 4 5 6 7 8 em1/e 0 0,36 0,64 0,82 0,91 0,96 0,98 1,00 1,00 em2/e 0 0,20 0,37 0,52 0,65 0,75 0,84 0,89 0,90 em1 is to be applied where girders are loaded by uniformly distributed loads or else by not less than 6 equally spaced single loads. em2 is to be applied where girders are loaded by 3 or less single loads. Intermediate values may be obtained by direct interpolation. R = length between zero-points of bending moment curve, i.e. unsupported span in case of simply supported girders and 0,6 x unsupported span in case of constraint of both ends of girder e = width of plating supported, measured from centre to centre of the adjacent unsupported fields. 2.3 Where the angle " between web of stiffeners or else of girders and the attached plating is less than 75E the required section modulus is to be multiplied by the factor 1/sin ". 2.4 The effective width of stiffeners and girders subjected to compressive stresses may be determined according to F.2.2, but is in no case to be taken greater than the effective breadth determined by 2.1. 3. Cantilevers Where cantilevers are fitted at every frame, the effective width of plating may be taken as the frame spacing. Where cantilevers are fitted at a greater spacing the effective breadth of plating at the respective cross section may approximately be taken as the distance of the cross section from the point on which the load is acting, however, not greater than the spacing of the cantilevers. F. Proof of Buckling Strength The calculation method is based on DIN-standard 18800 1. Definitions a = length of single or partial plate field [mm] b = breadth of single plate field [mm] " = aspect ratio of single plate field = n = number of single plate field breadths within the partial or total plate field longitudinal : stiffiner in the direction of the length a transverse : stiffiner in the direction of the length b Fig. 3.2 Definition of plate fields subject to buckling BKI - Rules for Hull - 2014
- 54. F Section 3 - Design Pinciples3-6/24 t = nominal plate thickness [mm] = ta – tK [mm] ta = plate thickness as built [mm] tK = corrosion addition according to K. [mm] Fx = membrane stress in x-direction [N/mm2 ] Fy = membrane stress in y-direction [N/mm2 ] J = shear stress in the x-y plane [N/mm2 ] Compressive and shear stresses are to be taken positive, tension stresses are to be taken negative. Note If the stresses in the x- and y- direction contain already the Poisson - effect, the following modified stress values may be used: Both stresses Fx* and Fy* are to be compressive stresses, in order to apply the stress reduction according to the following formulae: Fx= Fy= , = stresses containing the Poisson-effect Where compressive stress fulfils the condition Fy* < 0,3 @ Fx*, then Fy = 0 and Fx = Fx*. Where compressive stress fulfils the condition Fx* < 0,3 @ Fy*, then Fx = 0 and Fy = Fy*. When at least Fx* or Fy* is tensio n stress, then Fx = Fx* and Fy = Fy*. R = edge stress ratio according to Table 3.3 F1 = correction factor for boundary condition at the long. stiffeners according to Table 3.2 Fe = reference stress = [N/mm2 ] E = Young's modulus = [N/mm2 ] for steel = [N/mm2 ] for aluminium alloys Table 3.2 - Correction Factor F1 1,0 for stiffeners sniped at both ends Guidance values where both ends are effectively connected to adjacent structures * : 1,05 for flat bars 1,10 for bulb sections 1,20 for angle and tee-sections 1,30 for girders of high rigidity (e.g. bottom transverses) * Exact values may be determined by direct calculations. ReH = nominal yield point [N/mm2 ] for hull structural steels according to Section 2, B.2. = 0,2 % proof stress [N/mm2 ] for aluminium alloys BKI - Rules for Hull - 2014
- 55. Section 3 - Design Pinciples F 3-7/24 S = safety factor = 1,1 in general = 1,2 for structures which are exclusively exposed to local loads = 1,05 for combinations of statistically independent loads For constructions of aluminium alloys the safety factors are to be increased in each case by 0,1. 8 = reference degree of slenderness = K = buckling factor according to Tables 3.3 and 3.4. In general, the ratio plate field breadth to plate thickness shall not exceed b/t = 100. 2. Proof of single plate fields 2.1 Proof is to be provided that the following condition is complied with for the single plate field a @ b: Each term of the above condition shall not exceed 1,0. The reduction factors 6x, 6y and 6J are given in Table 3.3 and/or 3.4. Where Fx # 0 (tension stress), 6x = 1,0. Where Fy # 0 (tension stress), 6y = 1,0. The exponents e1, e2 and e3 as well as the factor B are calculated or set respectively : Exponents e1 – e3 and factor B plate field plane curved e1 1,25 e2 1,25 e3 1 + 6x @ 6y @ 2,0 B Fx and Fy positive (compression stress) 0 B Fx or Fy negative (tension stress) 1 –– 2.2 Effective width of plating The effective width of plating may be determined by the following formulae: bm = for longitudinal stiffeners am = for transverse stiffeners see also Fig. 3.2. The effective width of plating is not to be taken greater than the value obtained from E.2.1. BKI - Rules for Hull - 2014
- 56. F Section 3 - Design Pinciples3-8/24 Table 3.3 - Plane Plate Fields Load case Edge stress ratio R Aspect ratio " Buckling factor K Reductions factor 6 K = 6x = 1 for 8 # 8c 6x = for 8 > 8c c = 8c = K = K = " K = 6y = c = R = for 8 < 8c R = 0,22 for 8 $ 8c F = $ 0 8c = = 82 – 0,5 1 # # 3 c1 = 1 for due to direct loads c1 = $ 0 for due to bending (in general) c1 = 0 for due to bending in extreme load cases (e.g. w. t. bulkheads) H = $ R T = K = K = K = K = K = 6x = 1 for 8 # 0,7 6x = for 8 > 0,7 K = K = BKI - Rules for Hull - 2014
- 57. Section 3 - Design Pinciples F 3-9/24 Table 3.3 - Plane Plate Fields (Cont.) Load case Edge stress ratio R Aspect ratio " Buckling factor K Reductions factor 6 — K = 6J = 1 for 8 # 0,84 6J = for 8 > 0,84 KJ = KJ = — K = K’ @ r K’ = K according to line 5 r = Reductions factor = with # 0,7 and # 0,7 — K = 1,28 6x = 1 for 8 # 0,7 6x = for 8 > 0,7 K = — K = 6,97 6x = 1 for 8 # 0,83 6x = for 8 > 0,83 K = — K = 4 K = K = — K = 6,97 K = K = Explanations for boundary conditions : plate edge free plate edge simply supported plate edge clamped BKI - Rules for Hull - 2014
- 58. F Section 3 - Design Pinciples3-10/24 Table 3.4 - Curved plate field R/t 25001) Load case Aspect ratio b / R Buckling factor K Reduction factor 6 pe = external pressure [N/mm2 ] K = 6x = 12) for 8 # 0,4 6x = for 0,4 < 8 #1,2 6x = for 8 > 1,2 K = K = 6y = 1 2) for 8 # 0,25 6y = for 0,25 < 8 # 1 6y = 0.3 / 83 for 1 < 8 # 1,5 6y = 0.2 / 82 for 8 > 1,5 K = K = as in load case 1a K = K = 6J = 1 for 8 # 0,4 6J = for 0,4 < 8 # 1,2 6J = for 8 > 1,2 KJ = KJ = Explanations for boundary conditions : plate edge free plate edge simply supported plate edge clamped 1) For curved plate fields with a very large radius the 6-value need not to be taken less than derived for the expanded plane field. 2) For curved single fields. e.g. the bilge strake, which are located within plane partial or total fields, the reduction factor 6 may be taken as follows: Load case 1b : 6x = 0,8/82 1,0 ; load case 2: 6y = 0,65/82 1,0 BKI - Rules for Hull - 2014
- 59. Section 3 - Design Pinciples F 3-11/24 Note The effective width of stiffened flange plates of girders may be determined as follows:e m' Stiffening parallel to web of girder : b < = n = integral number of the stiffener spacing b inside the effective breadth “em” according to Table 3.1 in E.2.1 = int Stiffening perpendicular to web of girder: a $ = n @ < n = 2,7 @ # 1 e a m e = width of plating supported according to E.2.1 For b $ em or a < em respectively, b and a have to be exchanged. am and bm for flange plates are in general to be determined for R = 1. BKI - Rules for Hull - 2014
- 60. F Section 3 - Design Pinciples3-12/24 Stress distribution between two girders : c1 = 0 # c1 # 1 c2 = Fx1, Fx2 = normal stresses in flange plates of adjacent girder 1 and 2 with spacing e. = proportionate effective width of and respectively of girder 1 within the distance e = = proportionate effective width of and respectively of girder 2 within the distance e = y = distance of considered location from girder 1 Scantlings of plates and stiffeners are in general to be determined according to the maximum stresses Fx(y) at girder webs and stiffeners respectively. For stiffeners under compression arranged parallel to the girder web with spacing b no lesser value than 0,25 @ ReH shall be inserted for Fx(y=b). Shear stress distribution in the flange plates may be assumed linearly. 2.3 Webs and flanges For non-stiffened webs and flanges of sections and girders proof of sufficient buckling strength as for single plate fields is to be provided according to 2.1. Note Within 0,6 L amidships the following guidance values are recommended for the ratio web depth to web thickness and/or flange breadth to flange thickness: flat bars: angle-, tee and bulb sections: web: flange: bi = b1 or b2 according to Fig. 3.3, the larger value is to be taken. 3. Proof of partial and total fields 3.1 Longitudinal and transverse stiffeners Proof is to be provided that the continuous longitudinal and transverse stiffeners of partial and total plate fields comply with the conditions set out in 3.2 and 3.3. 3.2 Lateral buckling Fa = uniformly distributed compressive stress in the direction of the stiffener axis [N/mm2 ] = Fx for longitudinal stiffeners = Fy for transverse stiffeners BKI - Rules for Hull - 2014
- 61. Section 3 - Design Pinciples F 3-13/24 Fb = bending stress in the stiffeners = [N/mm2 ] M0 = bending moment due to deformation w of stiffener = [N @ mm] M1 = bending moment due to the lateral load p for continuous longitudinal stiffeners : = [N @ mm] for transverse stiffeners : = [N @ mm] p = lateral load [kN/m²] according to Section 4 FKi = ideal buckling force of the stiffener [N] FKix = for long. stiffeners FKiy = for transv. stiffeners Ix, Iy = moments of inertia of the longitudinal or transverse stiffener including effective width of plating according to 2.2 [cm4 ] Ix $ Iy $ pz = nominal lateral load of the stiffener due to Fx, Fy and J [N/mm2 ] for longitudinal stiffeners: pzx = for transverse stiffeners: pzy = Fx1 = [N/mm2 ] cx, cy= factor taking into account the stresses vertical to the stiffener's axis and distributed variable along the stiffener's length = 0,5 (1 + R) for 0 # R # 1 = for R < 0 R = edge stress ratio according to Table 3.3 Ax,Ay = sectional area of the longitudinal or transverse stiffener respectively [mm2 ] BKI - Rules for Hull - 2014
- 62. F Section 3 - Design Pinciples3-14/24 J1 = for longitudinal stiffeners: : m1 = 1,47 m2 = 0,49 : m1 = 1,96 m2 = 0,37 for transverse stiffeners: : m1 = 0,37 m2 = : m1 = 0,49 m2 = w = wo + w1 wo = assumed imperfection [mm], for long. stiffeners for transv. stiffeners however wo mm Note For stiffeners sniped at both ends wo shall not be taken less than the distance from the midpoint of plating to the neutral axis of the profile including effective width of plating. w1 = deformation of stiffener due to lateral load p at midpoint of stiffener span [mm] In case of uniformly distributed load the following values for w1 may be used : for longitudinal stiffeners: w1 = for transverse stiffeners: w1 = cf = elastic support provided by the stiffener [N/mm2 ] cfx = for long. stiffeners cpx = cx" = for a $ 2 b = for a < 2 b cfy = for transv. stiffeners BKI - Rules for Hull - 2014
- 63. Section 3 - Design Pinciples F 3-15/24 cpy = cy" = for n @ b $ 2 a = for n @ b < 2 a cs = factor accounting for the boundary conditions of the transverse stiffener = 1,0 for simply supported stiffeners = 2,0 for partially constraint stiffeners Wst = section modulus of stiffener (long. or transverse) [cm3 ] including effective width of plating according to 2.2. If no lateral load p is acting the bending stress Fb is to be calculated at the midpoint of the stiffener span for the fibre which results in the largest stress value. If a lateral load p is acting, the stress calculation is to be carried out for both fibres of the stiffener’s cross sectional area (if necessary for the biaxial stress field at the plating side). Note Longitudinal and transverse stiffeners not subjected to lateral load p have sufficient scantlings if their moments of inertia Ix and Iy are not less than obtained by the following formulae : Ix = [cm4 ] Iy = [cm4 ] 3.3 Torsional buckling 3.3.1 Longitudinal stiffeners : 6T = 1,0 for = for k = 8T = reference degree of slenderness 8T = FKiT = [N/mm2 ] For IP, IT, IT see Fig.3.3 and Table 3.5. BKI - Rules for Hull - 2014
- 64. F Section 3 - Design Pinciples3-16/24 Fig. 3.3 - Main dimensions of typical longitudinal stiffners IP = polar moment of inertia of the stiffener related to the point C [cm4 ] IT = St. Vernant’s moment of inertia of the stiffener [cm4 ] IT = sectorial moment of inertia of the stiffener related to the point C [cm6 ] g = degree of fixation = hw = web height [mm] tw = web thickness [mm] bf = flange breadth [mm] tf = flange thickness [mm] Aw = web area hw × tw Af = flange area bf × tf . 3.3.3 Transverse stiffeners For transverse stiffeners loaded by compressive stresses and which are not supported by longitudinal stiffeners, proof is to be provided in accordance with 3.3.1 analogously. Table 3.5 Formulas for the calculation of moments of inertia IP, IT, and IT Profile IP IT IT flat bar profile with bulb or flange + for bulb and angle profiles: for T - profiles: BKI - Rules for Hull - 2014
- 65. Section 3 - Design Pinciples G, H 3-17/24 G. Rigidity of Transverses and Girders The moment of inertia of deck transverses and girders, is not to be less than : I = c @ W @ R [cm4 ] c = 4,0 if both ends are simply supported = 2,0 if one end is constrained = 1,5 if both ends are constrained W = section modulus of the structural member considered [cm3 ] R = unsupported span of the structural member considered [m] H. Structural Details 1. Longitudinal members 1.1 All longitudinal members taken into account for calculating the midship section modulus are to extend over the required length amidships and are to be tapered gradually to the required end scantlings (see also Section 5, C.1). 1.2 Abrupt discontinuities of strength of longitudinal members are to be avoided as far as practicable. Where longitudinal members having different scantlings are connected with each other, smooth transitions are to be provided. Special attention in this respect is to be paid to the construction of continuous longitudinal hatch coamings forming part of the longitudinal hull structure. 1.3 At the ends of longitudinal bulkheads or continuous longitudinal walls suitable scarphing brackets are to be provided. 2. Transverses and girders 2.1 Where transverses and girders fitted in the same plane are connected to each other, major discontinuities of strength shall be avoided. The web depth of the smaller girder shall, in general, not be less than 60% of the web depth of the greater one. 2.2 The taper between face plates with different dimensions is to be gradual. In general the taper shall not exceed 1: 3. At intersections the forces acting in the face plates are to be properly transmitted. 2.3 For transmitting the acting forces the face plates are to be supported at their knuckles. For supporting the face plates of cantilevers, see Fig. 3.4. Fig. 3.4 - Support of face plates of cantilevers 2.4 Upon special approval the stiffeners at the knuckles may be omitted if the following condition is complied with: Fa = actual stress in the face plate at the knuckle [N/mm2 ] BKI - Rules for Hull - 2014
- 66. H Section 3 - Design Pinciples3-18/24 Fp = permissible stress in the face plate [N/mm2 ] bf = breadth of face plate [mm] be = effective breadth of face plate : be = tw = web thickness [mm] tf = face plate thickness [mm] b = [mm] c = cmax = 1 2" = knuckle angle [E], see Fig. 3.5 "max = 45E R = radius of rounded face plates [mm] = tf for knuckled face plates n1 = 1 for un-symmetrical face plates (face plate at one side only) = 2 for symmetrical face plates n2 = 0 for face plate not supported by brackets = # 1,0 for face plates of multi-web girders n3 = 3 if no radial stiffener is fitted = 3000 if two or more radial stiffeners are fitted or if one knuckle stiffener is fitted according to Fig. 3.5 (a). n3 = if one stiffener is fitted according to Fig. 3.5 (b). 3 # n3 # 3000 d = distance of the stiffener from the knuckle [mm] For proof of fatigue strength of the weld seam in the knuckle, the stress concentration factor KS (angle 2 " according to Fig. 3.5 < 35°) related to the stress Fa in the face plate of thickness tf may be estimated as follows and may be evaluated with case 5 of Table 20.3 : KS = n4 = 7,143 for > 8 = for 8 $ > 1,35 = 0,5 @ + 0,125 for 1,35 $ $ ! 0,25 The welding seam has to be shaped according to Fig. 3.6. BKI - Rules for Hull - 2014
- 67. Section 3 - Design Pinciples H 3-19/24 Scantlings of stiffeners (guidance) : thickness: tb = height: h = 1,5 @ b. 2.5 For preventing the face plates from tripping adequately spaced stiffeners or tripping brackets are to be provided. The spacing of these tripping elements shall not exceed 12@ bf. 2.6 The webs are to be stiffened to prevent buckling (see also F.). 2.7 The location of lightening holes shall be such that the distance from hole edge to face plate is not less than 0,3 x web depth. 2.8 In way of high shear stresses lightening holes in the webs are to be avoided as far as possible. Fig. 3.5 - Typical stiffeners of rounded of knuckled face plates Fig. 3.6 Welding and supporting of knuckles 3. Knuckles (general) Flanged structural elements transmitting forces perpendicular to the knuckle, are to be adequately supported at their knuckle, i.e. the knuckles of the inner bottom are to be located above floors, longitudinal girders or bulkheads. If longitudinal structures, such as longitudinal bulkheads or decks, include a knuckle which is formed by two butt-welded BKI - Rules for Hull - 2014
- 68. H, J Section 3 - Design Pinciples3-20/24 plates, the knuckle is to be supported in the vicinity of the joint rather than at the exact location of the joint. The minimum distance d to the supporting structure is to be at least: d = 25 + but not more than 50 mm, see Fig. 3.6. On bulk carriers at knuckles between inner bottom and tank side slopes in way of floors the welding cutouts have to be closed by collar plates or insert plates, see Fig. 3.7. In both cases a full penetration weld is required to inner bottom and bottom girder. Fig. 3.7 Knuckles of the double bottom J. Evaluation of Notch Stresses The notch stress FK evaluated for linear-elastic material behaviour at free plate edges, e.g. at hatch corners, openings in decks, walls, girders etc., should, in general, fulfill the following criterion: f = 1,1 for normal strength hull structural steel = 0,9 for higher strength hull structural steel with ReH = 315 N/mm2 = 0,8 for higher strength hull structural steel with ReH = 355 N/mm2 . = 0,73 for higher strength hull structural steel with ReH = 390 N/mm2 If plate edges are free of notches and corners are rounded-off, a 20 % higher notch stress FK may be permitted. A further increase of stresses may be permitted on the basis of a fatigue strength analysis as per Section 20. For some types of openings the notch factors Kt for the calculation of the notch stress FK are given in Figs. 3.8 and 3.9. They apply to stress conditions with uniaxial or biaxial normal stresses. In case of superimposed stresses due to longitudinal and shear loads, the maximum notch stress FKmax of rectangular openings with rounded corners can approximately be calculated as follows: FKmax = For F1 = tensile stress = For F1 = compressive stress Ktv = notch factor for equivalent stress = m, c = parameters according to Fig.3.10 BKI - Rules for Hull - 2014
- 69. Section 3 - Design Pinciples J 3-21/24 R, a = length and height of opening J1 = shear stress related to gross area of section F1 = longitudinal stress (in direction of length R of opening) related to gross area of section r = radius of rounded corner D = ratio of smaller length to radius of corner ( R/r or a/r) Dmin = 3 Fig.3.8 - Notch faktor Kt for rounded openings Fig. 3.9 Notch factor Kt for rectangular openings with rounded corners at uniaxial stress condition (left) and at biaxial stress condition (right) BKI - Rules for Hull - 2014
- 70. J, K Section 3 - Design Pinciples3-22/24 Fig. 3.10 Parameters m and c to determine the notch factors of rectangular openings loaded by superimposed longitudinal and shear stresses Note Because the notch factor and the equivalent stress are always positive, the sign of F1 governs the most unfavourable superposition of the stress components in any of the four corners. A load consisting of shear only, results in notch stresses of equal size with two positive and two negative values in the opposite corners. An exact evaluation of notch stresses is possible by means of finite element calculations. For fatigue investigations the stress increase due to geometry of cut-outs has to be considered, see Table 20.3. Note These notch factors can only be used for girders with multiple openings if there is no correlation between the different openings regarding deformations and stresses. K. Corrosion Additions 1. The scantling requirements of the subsequent Sections imply the following general corrosion addition tK : tK = 1,5 mm for t’ 10 mm = mm, max. 3,0 mm for t’ > 10 mm t’ = required rule thickness excluding tK [mm]. k = material factor according to Section 2, B.2. 2. For structural elements in specified areas tK is not to be less than given in Table 3.6. For corrosion protection see Section 38. Table 3.6 - Minimum corrosion addition Area tKmin [mm] In ballast tanks where the weather deck forms the tank top, 1,5 m below tank top1) . 2,5 In cargo oil tanks where the weather deck forms the tank top, 1,5 m below tank top. Horizontal members in cargo oil and fuel oil tanks. 2,0 Deck plating below elastically mounted deckhouses 3,0 Longitudinal bulkheads of ships assignedtothe Notation G and exposed to grab operation 2,5 1) tK = 2,5 mm for all structures within topside tanks of bulk carriers. BKI - Rules for Hull - 2014
- 71. Section 3 - Design Pinciples K, L 3-23/24 3. For structures in dry spaces such as box girders of container ships and for similar spaces the corrosion addition is: tK = , max. 2,5 mm however, not less than 1,0 mm. 4. Corrosion addition for hatch covers and hatch coamings are to be determined according to Section 17. L. Additional Stresses in Asymmetric Sections 1. Additional stresses for fatique strength analysis The additional stress Fh occurring in non-symmetric sections may be calculated by the following formulae : Q = load on section parallel to its web within the unsupported span Rf [kN] = p @ a @ Rf [kN] in case of uniformly distributed load p [kN/m2 ] Rf = unsupported span of flange [m] tf, bl, b2 = flange dimensions [mm] as shown Fig. 3.11. b1 b2 Wy = Section modulus of section related to the y-y axis including the effective width of plating [cm3 ] Wz = section modulus of the partial section consisting of flange and half of web area related to the z-z axis [cm3 ] (Bulb sections may be converted into a similar L-section) Fig. 3.11 - Asymmetrical profile c = factor depending on kind of load, stiffness of the section’s web and length and kind of support of the profile. For profiles clamped at both ends and constant area load c = 80 can be taken for approximation. A precise calculation may be required, e.g. for longitudinal frames of tankers. This additional stress Fh is to be added directly to other stresses such as those resulting from local and hull girder bending. 2. Correction of section modulus The required section modulus Wy according to A.2. is to be multiplied with the factor ksp according to Table 3.7 BKI - Rules for Hull - 2014
- 72. L Section 3 - Design Pinciples3-24/24 Table 3.7 - Increase factor ksp Type of Profile ksp Flat bars and symmetric T-profiles 1,00 Bulb profiles 1,03 Asymmetric T profiles 1,05 Rolled angels (L-profiles) 1,15 BKI - Rules for Hull - 2014
- 73. Section 4 - Design Loads A 4-1/10 Section 4 Design Loads A. General, Definitions 1. General. This Section provides data regarding design loads for determining the scantlings of the hull structural elements by means of the design formulae given in the following Sections or by means of direct calculations. The dynamic portions of the design loads are design values which can only be applied within the design concept of this Volume. 2. Definitions 2.1 Load centre 2.1.1For plates: – Vertical stiffening system: 0,5 @ stiffener spacing above the lower support of plate field, or lower edge of plate when the thickness changes within the plate field. – Horizontal stiffening system: Midpoint of plate field. 2.1.2For stiffeners and girders: Centre of span R. 2.2 Definition of symbols v0 = ship's speed according to Section 1, H.5. Dc = density of cargo as stowed [t/m3 ] D = density of liquids [t/m3 ] = 1,0 t/m3 for fresh water and sea water z = vertical distance of the structure's load centre above base line [m] x = distance from aft end of length L [m] p0 = basic external dynamic load = 2,1 @ (CB + 0,7) @ c0 @ cL @ f [kN/m2 ] for wave directions with or against the ship’s heading p01 = 2,6 @ (CB + 0,7) @ c0 @ cL [kN/m2 ] for wave directions transverse the ship’s heading CB = moulded block coefficient according to Section 1, H.4., where CB is not to be taken less than 0,60. c0 = wave coefficient = for L < 90 m = for 90 < L < 300 m = 10,75 @ cRW for L > 300 m BKI - Rules for Hull -2014 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only.
- 74. A, B Section 4 - Design Loads4-2/10 cL = length coefficient = for L < 90 m = 1,0 for L 90 m cRW = service range coefficient = 1,00 for unlimited service range = 0,90 for service range P = 0,75 for service range L = 0,60 for service range T f = probability factor = 1,0 for plate panels of the outer hull (shell plating, weather decks) = 0,75 for secondary stiffening members of the outer hull (frames, deck beams), but not less than fQ according to Section 5, D.1. = 0,60 for girders and girder systems of the outer hull (web frames, stringers, grillage systems), but not less than fQ/1,25 cD, cF = distribution factors according to Table 4.1. B. External Sea Loads 1. Load on weather decks 1.1 The load on weather deck is to be determined according to the following formula: pD = p0 [kN/m2 ] Table 4.1 Distribution factors for sea loads on ship's sides and weather decks Range Factor cD Factor cF 1) A 0 < 0,2 1,2 n 1,0 + M 0,2 < 0,7 1,0 1,0 F 0,7 1,0 1,0 + c = 0,15 L n 10 where: Lmin = 100 m Lmax = 250 m 1,0 + 1) Within the range A the ratio x/L need not be taken less than 0,1, within the range F the ratio x/L need not be taken greater than 0,93 Fig. 4.1 Longitudinal sections A, M, and F according to Table 4.1 BKI - Rules for Hull -2014
- 75. Section 4 - Design Loads B 4-3/10 1.2 For strength decks which are to be treated as weather decks as well as for forecastle decks the load is not to be less than the greater of the following two values : pDmin = 16 @ f [kN/m2 ] and pDmin = 0,7 @ p0 [kN/m2 ] 1.3 Where deck cargo is intended to be carried on the weather deck resulting in load greater than the value determined according to 1.1, the scantlings are governed by the greater load (see also C). Where the stowage height of deck cargo is less than 1,0 m, the deck cargo load may require to be increased by the following value : pz = 10 (1 S hc) [kN/m2 ] hc = stowage height of the cargo [m] 2. Load on ship's sides and of bow and stern structures 2.1 Load on ship's sides The external load ps on the ship's sides is to be determined according to 2.1.1 and 2.1.2. 2.1.1For elements the load centre of which is located below load waterline: ps = [kN/m2 ] for wave directions with or against the ship's heading. ps1 = [kN/m2 ] for wave directions transverse to the ship's heading including quasi-static pressure increase due to heel. y = horizontal distance between load centre and centreline [m] 2.1.2For elements the load centre of which is located above the load waterline: ps = [kN/m2 ] for wave directions with or against the ship's heading. ps1 = [kN/m2 ] for wave directions transverse to the ship's heading including quasi-static pressure increase due to heel. 2.2 Load on bow structures The design load for bow structures from forward to 0,1 L behind F.P. and above the ballast waterline in accordance with the draft Tb in 4. is to be determined according to the following formulae : pe = [kN'm2 ] with Lmax = 300m. c = 0,8 in general = for extremely flared sides where the flare angle " is larger than 40°. The flare angle " at the load centre is to be measured in the plane of frame between a vertical line and the tangent to the side shell plating. For unusual bow shapes pe can be specially considered. BKI - Rules for Hull -2014
- 76. B Section 4 - Design Loads4-4/10 pe shall not be smaller than ps according to 2.1.1 or 2.1.2 respectively. Aft of 0,1 L from F.P. up to 0,15 L from F.P. the pressure between pe and ps is to be graded steadily. The design load for bow doors is given in Section 6, H.3. 2.3 Load on stern structures The design load for stern structures from the aft end to 0,1 L forward of the aft end of L and above the smallest design ballast draught at the centre of the rudder stock up to T + c0/2 is to be determined according to the following formulae: pe = cA @ L [kN/m2 ] with Lmax = 300m. cA = 0,3 @ c $ 0,36 c = see 2.2 pe = shall not be smaller than ps according to 2.1.1 or 2.1.2 respectively 3. Load on the ship's bottom The external load pB of the ship's bottom is to be determined according to the greater of the following formulae: pB = 10 @ T + p0 @ cF [kN/m2 ] For wave direction with or against the ship’s heading. pB1 = [kN/m2 ] For wave direction transverse to the ship’s heading including quasi-static pressure increase due to heel. 4. Design bottom slamming pressure The design bottom slamming pressure in the fore body may be determined by the following formulae: pSL = [kN/m2 ] for L 150 m = [kN/m2 ] for L > 150 m c1 = 0 # c1 # 1,0 Tb = smallest designballast draught at F.P for normal ballast conditions [m],according to which the strengthening of bottom forward, see Section.6, E. has to be done. This value has to be recorded in the Class Certificate and in the loading manual. Where the sequential method for ballast water exchange is intended to be applied, Tb is to be considered for the sequence of exchange. Note With respect to the observation of the smallest design ballast draught Tb , an exception is possible, if during the exchange of ballast water weather conditions are observed the parameters of which are put down in the annex to the Certificate of Class. cSL = distribution factor, see also Fig. 4.2 cSL = 0 for 0,5 = for 0,5 < < 0,5 + c2 = 1,0 for 0,5 + c2 < < 0,65 + c2 BKI - Rules for Hull -2014
- 77. Section 4 - Design Loads B 4-5/10 = for > 0,65 + c2 c2 = 0,33 @ CB + c2max = 0,35 cA = 10/A = 1,0 for plate panels and stiffeners. A = loaded area between the supports of the structure considered [m2 ] 0,3 < cA 1,0 cs = cRW = see A.2.2 Fig. 4.2 Distribution factor cSL 5. Load on decks of superstructures and deckhouses 5.1 The load on exposed decks and parts of superstructure and deckhouse decks, which are not to be treated as strength deck, is to be determined as follows: pDA = pD @ n [kN/m2 ] pD = load according 1.1 n = = 1,0 for the forecastle deck nmin = 0,5 For deckhouses the value so determined may be multiplied by the factor b’ = breadth of deckhouse B’ = largest breadth of ship at the position considered. Except for the forecastle deck the minimum load is: pDAmin = 4 [kN/m2 ] 5.2 For exposed wheel house tops the load is not to be taken less than p = 2,5 [kN/m2 ] BKI - Rules for Hull -2014
- 78. C Section 4 - Design Loads4-6/10 C. Cargo Loads, Load on Accommodation Decks 1. Load on cargo decks 1.1 The load on cargo decks is to be determined according to the following formulae: pL = pc (1 + av) [kN/m2 ] pc = static cargo load [kN/m2 ] if no cargo load is given: pc = 7 @ h for 'tween decks but not less than 15 kN/m2 . h = mean 'tween deck height [m]. In way of hatch casings the increased height of cargo is to be taken into account. av = acceleration factor as follows: = F @ m F = 0,11 m = mo - 5 (mo - 1) for 0 < < 0,2 = 1,0 for 0,2 < < 0,7 = for 0,7 < < 1,0 mo = (1,5 + F) v0 = see A.2.2. v0 is not to be taken less than [kn] 1.2 For timber and coke deck cargo the load on deck is to be determined by the following formulae: pL = 5 @ hs (1 + av) [kN/m2 ] hs = stowing height of cargo [m]. 1.3 The loads due to single forces PE (e.g. in case of containers) are to be determined as follows: P = PE (1 + av) [kN]. 1.4 The cargo pressure of bulk cargoes is to be determined by the following formulae: pbc = pc (1 + av) [kN/m2 ] pc = static bulk cargo load = 9,81 A Dc A h A n [kN/m2 ] h = distance between upper edge of cargo and the load centre [m] n = " = angle [E] between the structural element considered and a horizontal plane ( = angle of repose of the cargo [E] 2. Load on inner bottom 2.1 The inner bottom cargo load is to be determined as follows: pi = 9,81 @ @ h (1 + av) [kN/m2 ] G = mass of cargo in the hold [t] V = volume of the hold [m3 ] (hatchways excluded) h = height of the highest point of the cargo above the inner bottom [m], assuming hold to be completely filled. BKI - Rules for Hull -2014
- 79. Section 4 - Design Loads C, D 4-7/10 av = see 1.1 For calculating av the distance between the centre of gravity of the hold and the aft end of the length L is to be taken. 2.2 For inner bottom load in case of ore stowed in conical shape, see Section 23, B.3. 3. Loads on accommodation and machinery decks 3.1 The deck load in accommodation and service spaces is: p = 3,5 ( 1 + av ) [kN/m2 ] 3.2 The deck load of machinery decks is: p = 8 ( 1 + av ) [kN/m2 ] 3.3 Significant single forces are also to be considered, if necessary. D. Load on Tank Structures 1. Design pressure for filled tanks 1.1 The design pressure for service conditions is the greater of the following values: p1 = 9,81@ h1 @ D (1 + av) + 100 @ pv [kN/m2 ] or p1 = [kN/m2 ] h1 = distance of load centre from tank top [m] av = see C.1.1 n = design heeling angle [E] for tanks = arctan in general fbk = 0,5 for ships with bilge keel = 0,6 for ships without bilge keel n > 20o for hatch covers of holds carrying liquids b = upper breadth of tank [m] y = distance of load centre from the vertical longitudinal central plane of tank [m] pv = set pressure of pressure relief valve [bar], if a pressure relief valve is fitted = working pressure during ballast water exchange [bar] = )z = distance from top of overflow to tank top [m] )pv = pressure losses in the overflow line [bar] )pvmin = 0,1 bar pvmin = 0,1 bar during ballast water exchange for both, the sequential method as well as the flow-through method = 0,2 bar (2,0 mWS) for cargo tanks of tankers (see also Rules for Machinery Installations, Volume III, Section 15). Smaller set pressures than 0,2 bar may be accepted in special cases. The actual set pressure will be entered into the Class Certificate. BKI - Rules for Hull -2014
- 80. D, E Section 4 - Design Loads4-8/10 1.2 The maximum static design pressure is: p2 = 9,81 @ h2 [kN/m2 ] h2 = distance of load centre from top of overflow or from a point 2,5 m above tank top, whichever is the greater. Tank venting pipes of cargo tanks of tankers are not to be regarded as overflow pipes. For tanks equipped with pressure relief valves and/or for tanks intended to carry liquids of a density greater than 1 t/m3 , the head h2 is at least to be measured to a level at the following distance hp above tank top: hp = 2,5 @ D [mWS], head of water [m], or = 10 @ pv [mWS], where pv > 0,25 @ D Regarding the design pressure of fuel tanks and ballast tanks which are connected to an overflow system, the dynamic pressure increase due to the overflowing is to be taken into account in addition to the static pressure height up to the highest point of the overflow system, see also Regulation for Construction, Equipment and Testing of Closed Fuel Overflow Systems. 2. Design pressure for partially filled tanks 2.1 For tanks which may be partially filled between 20% and 90% of their height, the design pressure is not to be taken less than given by the following formulae: 2.1.1For structures located within 0,25 Rt from the bulkheads limiting the free liquid surface in the ship's longitudinal direction: pd = [kN/m2 ] Rt = distance [m] between transverse bulkheads or effective transverse wash bulkheads at the height where the structure is located. 2.1.2For structures located within 0,25 bt from the bulkheads limiting the free liquid surface in the ship's transverse direction: pd = [kN/m2 ] bt = distance [m] between tank sides or effective longitudinal wash bulkhead at the height where the structure is located. nx = ny = x1 = distance of structural element from the tank’s end in the ship’s longitudinal direction [m] y1 = distance of structural element from the tank’s sides in the ship’s transverse direction [m] 2.2 For tanks with ratios Rt/L > 0,1 or bt/B > 0,6 a direct calculation of the pressure pd may be required. E. Design Values of Acceleration Components 1. Acceleration components The following formulae may be taken for guidance when calculating the acceleration components owing to ship's motions. Vertical acceleration: az = BKI - Rules for Hull -2014
- 81. Section 4 - Design Loads E 4-9/10 Transverse acceleration: ay = Longitudinal acceleration: ax = where A = The acceleration components take account of the following components of motion: Vertical acceleration (vertical to the base line) due to heave, and pitch. Transverse acceleration (vertical to the ship's side) due to sway, yaw , and roll including gravity component of roll. Longitudinal acceleration (in longitudinal direction) due to surge and pitch including gravity component of pitch. ax, ay and az are maximum dimensionless accelerations (i.e., relative to the acceleration gravity g) in the related direction x, y and z. For calculation purposes they are considered to act separately. a0 = L0 = length of ship L [m], but for determination of a0 the length L0 shall not be taken less than 100 m k = = metacentric height [m] kmin = 1,0 fQ = probability factor depending on probability level Q as outline in Table 4.2. Table 4.2 Probability factor fQ for a straightline spectrum of seaway-induced stress ranges Q fQ 10-8 10-7 10-6 10-5 10-4 1,000 0,875 0,750 0,625 0,500 2. Combined acceleration The combined acceleration a$ may be determined by means of the "acceleration ellipse" according to Fig. 4.3 (e.g. y-z- plane). BKI - Rules for Hull -2014
- 82. E Section 4 - Design Loads4-10/10 Fig. 4.3 Acceleration ellipse BKI - Rules for Hull -2014
- 83. Section 5 - Longitudinal Strength A 5-1/27 Section 5 Longitudinal Strength A. General 1. Scope 1.1 Forships ofcategoriesI-IIasdefinedin 4.1.3,thescantlingsofthelongitudinalhullstructure are to be determined onthebasis oflongitudinalbending moments and shear forces calculations.Forshipswhichdonotbelongtothesecategories i.e. in general for ships of less than 65 m in length, see also Section 7, A. 4. 1.2 The wave bending moments and shear forces specified under B.3. are design values which, in connection with the scantlingformulae, correspond to a probability level Q = 10-8 .Reducedvaluesmaybeusedforthepurposeofdetermining combined stresses as specified under D.1. 2. Calculation Particulars The curves of the still water bending moments and still water shear forces for the envisaged loading and ballast conditions are to be calculated. 3. Assumptions for calculation, loading conditions 3.1 The calculation of still water bending moments and shear forces is to be carried out for the following three loading conditions: .1 departure condition .2 arrival condition .3 transitory conditions (reduced provisions and ballast variations between departure and arrival) For determining the scantlings of the longitudinal hull structure the maximum values of the still water bending moments and shear forces are to be used. 3.2 In general, the loading conditions specified in 4.4.2 are to be investigated. 3.3 Forothershiptypesandspecialships,thecalculationofbendingmomentsandshearforcesforotherloading conditions according to the intended service may be required to be investigated, see also G. 3.4 Where for ships of unusual design and formas well as for ships with large deck openings a complex stress analysis of the ship in the seaway becomes necessary, the analysis will normally be done by using computer programs approved by BKI and processing the data prepared by the yard. 4. Loading guidance information 4.1 General, definitions 4.1.1 Loading guidance information is a means in accordance with Regulation 10(1) of ICLL which enables the master to load and ballast the ship in a safe manner without exceeding the permissible stresses. 4.1.2 An approved loading manual is to be supplied for all ships except those of Category II with length less than 90 m in which the deadweight does not exceed 30 % of the displacement at the summer loadline. In addition, an approved loading instrument is to be supplied for all ships of Category I of 100 m in length and above. In specialcases,e.g.extremeloadingconditionsorunusualstructuralconfigurations, BKImay also require an approvedloading instrument for ships of Category I less than 100 m in length. Special requirements for bulk carriers, ore carriers and combination carriers are given in Section 23, B.10. BKI - Rules for Hull - 2014
- 84. A Section 5 - Longitudinal Strength5-2/27 4.1.3 The following definitions apply : A loading manual is a document which describes : – the loading conditions on which the design of the ship has been based, including permissible limits of still water bending moment and shear force, – the results of the calculations of still water bending moments, shear forces and where applicable, limitations due to torsional and lateral loads, – the allowable local loading for the structure (hatch covers, decks, double bottom, etc.). A loading instrument is an approved analogue or digital instrument consisting of: – loading computer (Hardware) and – loading program (Software) by means of which it can be easily and quickly ascertained that, at specified read-out points, the still water bending moments, shear forces, and the still water torsional moments and lateral loads, where applicable, in any load or ballast condition will not exceed the specified permissible values. Anapprovedoperationalmanualisalwaystobeprovidedfortheloadinginstrument.Theoperationalmanualistobeapproved. Loadingcomputershavetobetypetestedandcertified,see also 4.5.1.Typeapprovedhardware maybewaived,ifredundancy is ensured by a second certified loading instrument. Type approval is required if: S the computers are installed on the bridge or in adjacent spaces S interfaces to other systems of ship operation are provided. For type approval the relevant rules and guidelines aret to be observed. Loading programs shall be approved and certified, see also 4.3.1 and 4.5.2. Single point loading programs are not acceptable. Ship categories for the purpose of this Section are defined for all classed seagoing ships of 65 m in length and above which were contracted for construction on or after 1st July 1998 as follows: Category I Ships: Ships with large deck openings where, according to F., combined stresses due to vertical and horizontal hull girder bending and torsional and lateral loads have to be considered. Chemical tankers and gas carriers. Ships more than 120 m in length, where the cargo and/or ballast may be unevenly distributed. Shipslessthan120m inlength,whentheirdesigntakesintoaccountunevendistributionofcargoorballast,belongtoCategory II. Category II Ships: Ships with arrangement giving small possibilities for variationinthedistributionofcargoandballast(e.g.passengervessels). Ships on regular and fixed trading patterns where the loading manual gives sufficient guidance. The exceptions given under Category I. 4.2 Conditions of approval of loading manuals Manualshouldcontainthedesignloadingand ballastconditions, subdivided into departureandarrivalconditions, andballast exchange at sea conditions, where applicable, upon which the approval of the hull scantlings is based. 4.4.2 contains as guidance only a list of the loading conditions which in general are to be included in the loading manual. In case of modifications resulting in changes in the main data of the ship, a new approved loading manual is to be issued. The loading manual shall be prepared in a language understood by the users. If this language is not English, a translation into English is to be included. 4.3 Conditions of approval of loading instruments 4.3.1 The approval of the loading instrument is to include: BKI - Rules for Hull - 2014
- 85. Section 5 - Longitudinal Strength A 5-3/27 – verification of type approval, if required, see 4.1.3 – verification that the final data of the ship has been used, – acceptance of number and position of read-out points, – acceptance of relevant limits for all read-out points, – checking of proper installation and operation of the instrumentonboardinaccordancewithagreedtestconditions, and availability of the approved operation manual. 4.3.2 4.5 contains information on approval procedures for loading instruments. 4.3.3 Incaseofmodificationsimplyingchangesinthemaindataoftheship,theloadingprogramistobemodified accordingly and newly approved. 4.3.4 The operation manual and the instrument output must be prepared in a language understood by the users. If this language is not English, a translation into English is to be included. 4.3.5 The operation of the loading instrument is to be verified upon installation. It is to be checked that the agreed test conditions and the operation manual for the instrument are available on board. The permissible limits for the still water bending moments and shear forces to be applied for the ballast water exchange at sea are to be determined in accordance with E., where B.3.1 is to be used for the wave bending moments and B.3.2 for the wave shear forces. 4.4 Design cargo and ballast loading conditions 4.4.1 In general the loading manual should contain the design loading and ballast conditions, subdivided into departure andarrivalconditionsand,whereapplicable,ballastexchangeatseaconditionsupon which the approvalofthehullscantlings is based. Where the amount and disposition of consumables at any transitory stage of the voyage are considered to result in a more severe loading condition, calculations for such transitory conditions are to be submitted in addition to those for departure and arrival conditions. Also, where any ballasting and/or deballasting is intended during voyage, calculations of the transitory conditions before andafterballastingand/ordeballasting any ballast tank are tobe submitted and, after approval,includedinthe loadingmanual for guidance. 4.4.1.1 Partially filled ballast tanks in ballast loading condition Ballastloadingconditionsinvolving partially filledpeakand/or other ballast tanks at departure, arrivalorduringintermediate conditions are not permitted to be used as design conditions, unless – design stress limits are not exceeded in all filling levels between empty and full. – for bulk carriers, where applicable, the requirements of G. are complied with for all filling levels between empty and full. Todemonstratecompliancewithallfillinglevelsbetweenemptyandfull,itwillbeacceptableif,ineachconditionatdeparture, arrival and where required by 4.3.2 any intermediate condition, the tanks intended to be partially filled are assumed to be: – empty – ful – partially filled at intended level Where multiple tanks are intended to be partially filled, all combinations of empty, full or partially filled at intended level for those tanks are to be investigated. However, for conventional ore carriers with large wing water ballast tanks in cargo area, where empty or full ballast water filling levels of one or maximum two pairs of these tanks lead to the ship's trim exceeding one of the following conditions, itissufficienttodemonstratecompliancewithmaximum,minimumandintendedpartialfillinglevelsoftheseoneormaximum two pairs of ballast tanks such that the ship's condition does not exceed any of these trim limits. Filling levels of all other wing ballast tanks are to be considered between empty and full. BKI - Rules for Hull - 2014
- 86. A Section 5 - Longitudinal Strength5-4/27 The trim conditions mentioned above are: – trim by stern of 0,03 L, or – trim by bow of 0,015 L, or – any trim that cannot maintain propeller immersion (I/D) not less than 25% I = the distance from propeller centreline to the waterline D = propeller diameter The maximumand minimumfilling levels of the above mentioned pairs of side ballast tanks are to be indicated in the loading manual. 4.4.1.2 Partially filled ballast tanks in combination with cargo loading conditions In such cargo loading conditions, the requirementsin4.4.1.1applytothepeaktanksonly.Requirementsof4.4.1.1and 4.4.1.2 are not applicable to ballast water exchange using the sequential method. 4.4.2 In particular the following loading conditions should be included: For Dry-Cargo Ships, Containerships, Ro-Ro Ships, Refrigerated Carriers, Ore Carriers and Bulk Carriers: – loading conditions at maximum draught, – ballast conditions, – special loading conditions, e.g. container or light load conditions at less than the maximum draught, heavy cargo, empty holds or non-homogeneous cargo conditions, deck cargo conditions, etc., where applicable, – short voyages or harbour conditions, where applicable, – docking condition afloat, – loading and unloading transitory conditions, where applicable. – allloadingconditionsspecifiedinSection23,F.4.forshipswithNotationsBC-A,BC-BorBC-C,whereapplicable For oil tankers (see also Section 24, B.) : – homogeneous loadingconditions(excludingdryandsegregatedballasttanks)andballastorpartloadedconditions for both departure and arrival, – any specified non-uniform distribution of loading, – mid-voyage conditionsrelatingtotankcleaningorotheroperationswherethesediffersignificantlyfromtheballast conditions, – docking condition afloat, – loading and unloading transitory conditions. For chemical tankers : – conditions as specified for oil tankers, – conditions for high density or heated cargo, see also Section 12, A.6., – segregated cargo where these are included in the approved cargo list. For Liquefied gas carriers : – homogeneous loading conditions for all approved cargoes for both arrival and departure, – ballast conditions for both arrival and departure, – cargo condition where one or more tanks are empty or partially filled or where more than one type of cargo having significantly different densities is carried for both arrival and departure, – harbourconditionforwhichanincreasedvapourpressurehasbeenapproved(seeRulesforShipsCarryingLiquefied Gas in Bulk, Volume IX, Section 4, 4.2.6.4), – docking condition afloat. BKI - Rules for Hull - 2014
- 87. Section 5 - Longitudinal Strength A 5-5/27 For combination carriers : – conditions as specified for oil tankers and cargo ships 4.5 Approval procedures of loading instruments 4.5.1 Type test of the loading computer The type test requires: – The loading computer to undergo successful tests in simulated conditions to prove its suitability for shipboard operation, – The testing of a design may be waived if a loading instrument has been tested and certified by an independent and recognized authority, provided the testing program and results are considered satisfactory. 4.5.2 Certification of the loading program 4.5.2.1 After the successful type test of the hardware, if required, see 4.1.3, the producer of the loading program shall apply at BKI for certification. 4.5.2.2 The number and location of read-out points are to be to the satisfaction of BKI. Read-out points should usually be selected atthepositionofthetransversebulkheadsorotherobviousboundaries.Additionalread-outpointsmayberequired between bulkheads of long holds or tanks or between container stacks. 4.5.2.3 BKI will specify: – the maximum permissible still water shear forces, bending moments (limits) at the agreed read-out points and when applicable, the shear force correction factors at the transverse bulkheads, – when applicable, the maximum permissible torsional moments, – also when applicable the maximum lateral load. 4.5.2.4 For approval of the loading program the following documents have to be submitted: – operation manual for the loading program, – print-outs of the basic ship data like distribution of light ship weight, tank and hold data etc., – print-outs of at least 4 test cases, – diskettes with loading program and stored test cases. The calculated strength results at the fixed read-out points shall not differ from the results of the test cases by more than 5 % related to the approved limits. 4.5.3 Loading instrument Final approval of the loading instrument will be granted when the accuracy of the loading instrument has been checked after installation on board ship using the approved test conditions. Iftheperformanceoftheloadinginstrumentistobefoundsatisfactory,theSurveyorwillfixasasignofapprovalaself-adhering label, provided for this purpose, to the loading instrument casing in a prominent position. The date of approval (month, year) and the number of the corresponding approval certificate are stated on the proof label. A certificate will then be issued. A copy of the Certificate is to be included in the operation manual. 4.6 Class maintenance of loading guidance information At each Annual and Class Renewal Survey, it is to be checked that the approved loading guidance information is available on board. Theloadinginstrumentistobecheckedforaccuracyatregularintervalsbytheship'sMasterbyapplyingtestloadingconditions. At each Class Renewal Survey this checking is to be done in the presence of the Surveyor. 5. Definitions k = material factor according to Section 2, B.2. CB = block coefficient as defined in Section 1,H.4. CB is not to be taken less than 0,6 BKI - Rules for Hull - 2014
- 88. A, B Section 5 - Longitudinal Strength5-6/27 x = distance [m] between aft end of length L and the position considered v0 = speed of the ship [kn] according to Section.1, H.5. Iy = moment of inertia of the midship section [m4 ] around the horizontal axis at the position x/L eB = distance [m] between neutral axis of hull section and base line eD = distance [m] between neutral axis of hull section and deck line at side ez = vertical distance of the structural element considered from the horizontal neutral axis [m] (positive sign for above the neutral axis, negative sign for below) WB = section modulus of section [m3 ] related to base line WD = section modulus of section [m3 ] related to deck line at side S = first moment of the sectional area considered [m3 ] related to the neutral axis MT = total bending moment in the seaway [kNm] = MSW + MWV MSW = permissible vertical still water bending moment [kNm] (positive sign for hogging, negative sign for sagging condition) MWV= verticalwavebendingmoment[kNm](positivesignforhogging,MWVhog,negativesignforsaggingcondition, MWVsag) MWH= horizontal wave bending moment [kNm] (positive signfor tension starboard side, negative for compression in starboard side) MST = static torsional moment [kNm] MWT = wave induced torsional moment [kNm] QT = total vertical shear force in the seaway [kN] = QSW + QWV QSW = permissible vertical still water shear force [kN] QWV = vertical wave shear force [kN] QWH = horizontal wave shear force [kN]. Sign rule see Fig. 5.1 Fig. 5.1 Sign rule B. Loads on the Ship’s Hull 1. General In general the global loads on the hull in a seaway can be calculated with the formulae stated below. For ships of unusual form and design (e.g. L/B < 5, B/H $ 2,5, L > 500 m or CB < 0,6) and for ships with a speed of: v0 > 1,6 @ [kn] as well as for ships with large bow and stern flare and with cargo on deck in these areas BKI may require determination of BKI - Rules for Hull - 2014
- 89. Section 5 - Longitudinal Strength B 5-7/27 wavebendingmomentsaswellastheirdistributionovertheship'slengthbyapprovedcalculationprocedures.Suchcalculation procedures shall take into account the ship's motions in a natural seaway. 2. Still Water Loads 2.1 General Due to the provided loading cases the vertical longitudinal bending moments and shear forces are to be proved by calculations for cases in intact conditions (MSW, QSW) and if required (see G.1.) for damage conditions (MSWf, QSWf). If statical torsional moments are likely to be expected from the loading or construction of the ship, they have to be taken into account. Still water loads have to be superimposed with the wave induced loads according to 3. 2.2 Guidance values for containerships with irregular loading 2.2.1 Still water bending moments When determining the required section modulus of the midship section of containerships in the range: = 0,3 to = 0,55 it is recommended to use at least the following initial value for the hogging still water bending moment : MSWini = n1 @ c0 @ L2 @ B @ (0,123 ! 0,015 @ CB) [kNm] n1 = < 1,2 n = according to 2.2.2 MSWini shall be graduated regularly to ship’s ends. 2.2.2 Static torsional moment The maximum static torsional moment may be determined by: MST max = [kNm] CC = maximum permissible cargo capacity of the ship [t] = n . G n = maximum number of 20'-containers (TEU) of the mass G the ship can carry G = mean mass of a single 20'-container [t] For the purpose of a direct calculation the following envelope curve of the static torsional moment over the ship's length is to be taken: MST = [kNm] cT1, cT2 = distribution factors, see also Fig. 5.2 cT1 = for = for cT2 = for = for BKI - Rules for Hull - 2014
- 90. B Section 5 - Longitudinal Strength5-8/27 Fig. 5.2 - Distribution factors cT1 and cT2 for torsional moments 3. Wave induced loads 3.1 Vertical wave bending moments The vertical wave bending moment are to be determined according to the following formulae: MWV= L2 @ B @ c0 @ c1 @ cL @ cM [kNm] c0,cL = see Section 4,A.2.2 c1 = hogging/sagging condition as follows: c1H = 0,19 @ CB for hogging condition c1S = S 0,11 (CB + 0,7) for sagging condition cM = distribution factor, see also Fig. 5.3 cMH = hogging condition = for 0 < 0,4 = 1,0 for 0,4 0,65 = for 0,65 < 1 cMS = sagging condition = cv @ for 0 < 0,4 = cv for 0,4 0,65 @ cv = for 0,65 @ cv < 1 Fig. 5.3 - Distribution factor cM and influence factor cv BKI - Rules for Hull - 2014
- 91. Section 5 - Longitudinal Strength B 5-9/27 cv = influence with regard to speed v0 of the vessel = 1,0 for L the value need not be less than 100 = 1,0 for damaged condition. 3.2 Vertical wave shear forces The vertical wave shear forces are to be determined by the following formulae: QWV = c0 @ cL @ L @ B (CB + 0,7) cQ [kN] c0, cL = see Section 4, A.2.2 cQ = distribution factor according to Table 5.1, see also Fig. 5.4. m = c1H, c1S = see 3.1. Table 5.1 - Distribution factor cQ Range for positive shear forces for negative shear forces 0 < 0,2 1,38 @ m S 1,38 0,2 < 0,3 0,276 @ m S 0,276 0,3 < 0,4 1,104 m S 0,63 + (2,1 S 2,76 m) 0,4 < 0,6 0,21 S 0,21 0,6 < 0,7 (3 cv – 2,1) + 0,21 0,7 < 0,85 0,3 @ cv S 0,3 m 0,85 # 1,0 Fig 5.4 Distribution factor cQ BKI - Rules for Hull - 2014
- 92. B Section 5 - Longitudinal Strength5-10/27 3.3 Horizontal bending moments MWH = 0,32 @ L @ QWHmax @ cM [kNm] cM = see 3.1, but for cv = 1 QWHmax = see 3.4 3.4 Horizontal shear forces QWHmax = [kN] cN = cNmin = 2 QWH = QWHmax A cQH cQH = distribution factor according to Table 5.2, see also Fig. 5.5 Fig 5.5 Distribution factor cQH Table 5.2 - Distribution factor cQH Range cQH 1 0,5 1,0 3.5 Torsional moments The maximum wave induced torsional moment is to be determined as follows : MWTmax = [kNm] a = amin = 0,1 cN = see 3.4 BKI - Rules for Hull - 2014
- 93. Section 5 - Longitudinal Strength B, C 5-11/27 ZQ = distance [m] between shear centre and a level at above the basis When a direct calculation is performed, for the wave induced torsional moments the following envelope curve is to be taken: MWT = [kNm] cWT = distribution factor, see also Fig. 5.6 = cT1, cT2 = see 2.2.2 Fig. 5.6 - Distribution factor CWT Note The envelope can be approximated by superposition of both distributions according to Fig. 5.2. C. Section Moduli, Moments of Inertia, Shear and Buckling Strength 1. Section moduli as a function of the longitudinal bending moments 1.1 The section moduli related to deck WD respectively WD’ or bottom WB are not to be less than: W = [m3 ] fr = 1,0 in general = according to F.2. for ships with large openings Fp = permissible longitudinal bending stress [N/mm2 ] = cs @ Fp0 Fp0 = 18,5 for L < 90 m = for L $ 90 m cs = 0,5 + for 0 < 0,30 = 1,0 for 0,30 0,70 = for 0,70 < 1,0 1.2 Fortherangesoutside0,4Lamidshipsthefactorcs maybeincreaseduptocs =1,0,ifthisisjustifiedunderconsideration of combined stresses due to longitudinal hull girder bending (including bending to impact loads), horizontal bending, torsion and local loads and under consideration of buckling strength. BKI - Rules for Hull - 2014
- 94. C Section 5 - Longitudinal Strength5-12/27 2. Minimum midship section modulus 2.1 The section modulus related to deck and bottom is not to be less than the following minimum value: Wmin= k @ c0 @ L2 @ B A(CB + 0,7)A10-6 [m3 ] c0 according to Section 4, A.2.2 for unlimited service range. For ships classed for a restricted range of service, the minimum section modulus may be reduced as follows: P (Restricted Ocean Service) : by 5% L (Coasting Service) : by 15% T (Shallow Water Service) : by 25% 2.2 The scantlings of all continuous longitudinal members based on the minimum section modulus requirement are to be maintained within 0,4 L amidships. 3. Midship section moment of inertia The moment of inertia related to the horizontal axis is not to be less than : Iy = 3 @ 10-2 @ W @ [m4 ] W see 1.1 and/or 2.1, the greater value is to be taken. 4. Calculation of section moduli 4.1 The bottomsection modulus WB and thedecksectionmodulusWD aretobedeterminedbythefollowing formulae: WB = [m3 ] WD = [m3 ] Continuous structural elements above eD (e.g. trunks, longitudinal hatch coamings, decks with a large camber, longitudinal stiffners and longitudinal girders arrangedabovedeck,bulwarkscontributingtolongitudinalstrengthetc.)maybeconsidered when determining the section modulus, provided they have shear connection with the hull and are effectively supported by longitudinal bulkheads or by rigid longitudinal or transverse deep girders. The fictitious deck section modulus is then to be determined by the following formulae : W’D = [m3 ] e’D = [m] z = distance [m] from neutral axis of the cross section considered to top of continuous strength member y = distance [m] from centre line to top of continuous strength member. It is assumed that e’D > eD. For ships with multi-hatchways see 5. 4.2 When calculating the section modulus, openings of continuous longitudinal strength members shall be taken into account. Large openings, i.e. openings exceeding 2,5 m in length or 1,2 m in breadth and scallops, where scallop-welding is applied, are always to be deducted from the sectional areas used in the section modulus calculation. Smaller openings (manholes, lightening holes, single scallops in way of seams etc.) need not be deducted provided that the sumof their breadths or shadow area breadths in one transverse section is not reducing the section modulus at deck or bottom by more than 3 % and provided that the height of lightening holes, draining holes and single scallops in longitudinals or longitudinal girders does not exceed 25 % of the web depth, for scallops 75 mm at most. (See fig.5.7.) A deduction-free sumof smaller openingbreadths in one transverse section in the bottomor deck area of 0,06 (B -Gb) (where B = breadth of ship at the considered transverse section, Gb = sum of breadth of openings) may be considered equivalent to the above reduction in section modulus by 3%. BKI - Rules for Hull - 2014
- 95. Section 5 - Longitudinal Strength C 5-13/27 The shadow area will be obtained by drawing two tangent lines with an opening angle of 30E (see Fig. 5.7). 4.3 Where in the upper and lower flange thicknesses of continuous longitudinal structures forming boundaries of oil or ballast tanks have been reduced due to arrangement of an effective corrosion protection system, these thickness reduction shall not result in a reduction of midship section modulus of more than 5%. Note In case of large openings local strengthenings may be required which will be considered in each individual case (see also Section 7, A.3.1). Fig 5.7 Shadow area 5. Ships with multi-hatchways 5.1 Forthedeterminationofsectionmoduli100%effectivityofthelongitudinalhatchwaygirdersbetweenthe hatchways may be assumed, if an effective attachment of these girders is given. 5.2 An effective attachment of the longitudinal hatchway girder must fulfil the following condition : The longitudinal displacement fL of the point of attachment due to action of a standard longitudinal force PL is not to exceed fL = [mm] R = length of transverse hatchway girder according to Fig. 5.8 [m] PL = 10 @ ALG [kN] ALG = entire cross sectional area of the longitudinal hatchway girder [cm2 ] see also Fig. 5.8. Where the longitudinal displacement exceeds fL = R/20, special calculation of the effectivity of the longitudinal hatchway girders may be required. Fig. 5.8 Ship with multi-hatchways BKI - Rules for Hull - 2014
- 96. C Section 5 - Longitudinal Strength5-14/27 5.3 For the permissible combined stress see Section.10, E.3. 6. Shear strength The shear stress in longitudinal structures due to the vertical transverse forces QT acc. to E.2. and shall not exceed 110/ k [N/mm2 ]. For ships with large deck openings and/or for ships with large static torsional moments, also the shear stresses due to MSTmax have to be considered adversely, i.e. increasing the stress level. The shear stresses are to be determined according to D.3. 7. Proof of buckling strength AlllongitudinalhullstructuralelementssubjectedtocompressivestressesresultingfromMT accordingtoE.1andQT according to E.2. are to be examined for sufficient resistance to buckling according to Section 3, F. For this purpose the following load combinations are to be investigated : - MT and 0,7 @ QT - 0,7 @ MT and QT . 8. Ultimate load calculation of the ship's transverse sections 8.1 Inextremeconditions,largerloadsthanreferredtoinB.mayoccur.Therefore,dimensioningoflongitudinalstructures is to be verified by proving the ultimate capacity according to 8.2 and 8.3. The calculations are to include those structural elements contributing to the hull girder longitudinal strength and are to be based on gross scantlings. The following safety factors are to be assumed: (R = 1,20 (WV = 1,20 8.2 Ultimate vertical bending moment MSWf = maximum vertical still water bending moment in flooded conditions [kNm]. For a transverse section under consideration, the most severe levels of vertical still water bending moments are to be selected from those cases of flooding used in the damage stability calculations (see Section 36). cs = stress factor according to 1.1 MU = ultimate vertical bending moments of the ship's transverse section in the hogging (MU,H) and sagging (MU,S) conditions [kNm]. See 8.2.1. MUf = ultimateverticalbendingmomentsoftheship'sdamagedtransversesectioninthe hogging (MUf,H) and sagging (MUf,S) conditions [kNm]. If no assumptions regarding the extent of damage are prescribed, MUf = 6dM @ MU, where 6dM is a reduction factor for the ultimate moments in damaged conditions (6dM # 1). The reduction factor 6dM equals 1 unless a smaller value is specified by the owner or shipyard. 8.2.1 Progressive collapse analysis A progressive collapse analysis is to be used to calculate the ultimate vertical bending moments of a ship's transverse section. The procedure is to be based on a simplified incremental-iterative approach where the capacities are defined as the peaks of the resulting moment-curvature curve (M-P) in hogging (positive) and sagging (negative) conditions, i.e. P is the hull girder curvature [1/m]. See Fig. 5.9. BKI - Rules for Hull - 2014
- 97. Section 5 - Longitudinal Strength C 5-15/27 Fig. 5.9 Moment-curvature curve The main steps to be used in the incremental-iterative approach are summarized as follows: Step 1 The ship's transverse section is to be divided into plate-stiffener combinations (see 8.2.2.2 (a)) and hard corners (see 8.2.2.2(b)). Step2 The average stress – averagestrainrelationshipsFCRk-,forall structural elements (i.e. stiffenerplate combinations and hard corners) are to be defined, where the subscript k refers to the modes 0, 1, 2, 3 or 4, as applicable (see 8.2.2). Step 3 The initial and incremental value of curvature )P is to be defined by the following formula : ReH = minimum nominal yield point of structural elements in the strength deck [N/mm2 ] zD = z co-ordinate of strength deck at side [m] (see also Fig. 5.1) zNA,e = z co-ordinate of elastic neutral axis for the ship's transverse section [m] Step 4 For the value of curvature, Pj = Pj-1 + )P, the average strain ,+i,j = Pj zi and corresponding average stress Fi,j is to be defined for each structural element i (see 8.2.2). For structural elements under tension, Fi,j = FCR0 (see 8.2.2.1). For plate-stiffener combinations under compression, Fi,j = minimum [FCR1, FCR2, FCR3] (see 8.2.2.2 (a)). For hard corners under compression, Fi,j = FCR4 (see 8.2.2.2 (b)). zi = z co-ordinate of ith structural element [m] relative to basis, see also Fig. 5.11 Step 5 For the value of curvature, Pj = Pj-1 + )P, the height of the neutral axis zNA,j is to be determined iteratively through force equilibrium over the ship's transverse section: m is the number of structural elements located above zNA,j n is the number of structural elements located below zNA,j Ai = cross-sectional area of ith plate-stiffener combination or hard corner Step 6 For the value of curvature, Pj = Pj-1 + )P, the corresponding bending moment is to be calculated by summing the contributions of all structural elements within the ship's transverse section : Steps 4 through 6 are to be repeated for increasing increments of curvature until the peaks in the M-P curve are well defined. The ultimate vertical bending moments MU,H and MU,S are to be taken as the peak values of the M-P curve. 8.2.2 Average stress - average strain curves A typical average stress – average strain curve FCRk-g for a structural element within a ship's transverse section is shown in Fig. 5.10, where the subscript k refers to the modes 0, 1, 2, 3 or 4, as applicable. BKI - Rules for Hull - 2014
- 98. C Section 5 - Longitudinal Strength5-16/27 Fig. 5.10 - Typical average stress - average strain curve 8.2.2.1 Negative strain (FCRO - g) The portion of the curve corresponding to negative strain (i.e. tension) is in every case to be based on elasto-plastic behavior (i.e. material yielding) according to the following : [N/mm2 ] k = edge function = –1 for g < –1 = g for –1 # g # 0 , = relative strain = gE = element strain gy = strain at yield stress in the element = 8.2.2.2 Positive strain The portion of the curve corresponding to positive strain (i.e. compression)istobebasedonsomemodeofcollapse behaviour (i.e. buckling) for two types of structural elements; (a) plate-stiffener combinations and (b) hard corners. See Fig. 5.11. Fig. 5.11 Structural elements (a) Plate-stiffener combinations (FCR1-g,FCR2-g,FCR3-g) Plate-stiffener combinations are comprised of a single stiffener together with the attached plating from adjacent plate fields. Under positive strain, three average stress – average strain curves are to be defined for each plate stiffener combination based on beam column buckling (FCR1-g), torsional buckling (FCR2-g) and web/flange local buckling (FCR3-g). (i) Beam column buckling FCR1-g Thepositivestrainportionoftheaveragestress–average straincurveFCR1-gbasedonbeamcolumnbucklingofplate-stiffener combinations is described according to the following : BKI - Rules for Hull - 2014
- 99. Section 5 - Longitudinal Strength C 5-17/27 M = edge function = g for 0 # g # 1 = 1 for g >1 6BC = reduction factor = 1 for 8K # 0,2 = for 8K > 0,2 8K = kD = (1 + 0,21 (8K – 0,2) + 8K 2 ) / 2 a = length of stiffener [mm] AX = sectional area of stiffener with attached shell plating of breadth (bm,1/2 + bm,2/2) [mm2 ] IX = moment of inertia of stiffener with attached shell plating of breadth (bm,1/2 + bm,2/2) [cm4 ] bm,1, bm,2 = effective breadths of single plate fields on sides 1 and 2 of stiffener [mm] according to Section 3, F.2.2, in general based on Load Case 1 of Table 3.3, where the reference degree of slenderness is to be defined as b1, b2= breadths of single plate fields on sides 1 and 2 of stiffener [mm], see also Fig. 5.11 t1, t2 = thicknesses of single plate fields on sides 1 and 2 of stiffener [mm] AStif = sectional area of the stiffener without attached plating [mm2 ] (ii) Torsional buckling FCR2-g The positive strain portion of the average stress – average strain curve FCR1-g based on torsional buckling of plate-stiffener combinations is described according to the following : 6I = reduction factor according to Section 3, F.3.3. (iii) Web/flange local buckling FCR3 - g Thepositivestrainportionoftheaveragestress–averagestraincurveFCR3 -gbasedonweb/flangelocalbucklingofplate-stiffener combinations is described according to the following : hw,m, bf,m = effective widthofweb/flange plating[mm]accordingtoSection3,F.2.2(generallybasedonLoad Case 3ofTable3.3forflatbarsandflanges,otherwiseLoadCase1)wherethereferencedegreeofslenderness is to be defined as hw = web height [mm] tw = web thickness [mm] BKI - Rules for Hull - 2014
- 100. C Section 5 - Longitudinal Strength5-18/27 bf = flange breadth, where applicable [mm] tf = flange thickness, where applicable [mm] (b) Hard corners (FCR4-g) Hard corners are sturdy structural elements comprised of plates not lying in the same plane. Bilge strakes (i.e. one curved plate), sheer strake-deck stringer connections (i.e. two plane plates) and bulkhead-deck connections (i.e. three plane plates) are typical hard corners. Under positive strain, single average stress – average strain curves are to be defined for hard corners based on plate buckling (FCR4-g). ( i ) Plate buckling FCR4-g bm,i = effective breadths of single plate fields [mm] according to Section 3, F.2.2, as applicable, in general based onapplicableLoadCasesinTable3.3andTable3.4,wherethereferencedegreeofslendernessistobedefined as bi = breadth of single plate fields [mm], see also Fig. 5.11 ti = thickness of single plate fields [mm] n = number of plates comprising hard corner 8.3 Ultimate vertical shear force QSWf = maximumverticalstillwatershearforceinfloodedconditions[kN].Foratransverse section under consideration, the most severe levels of vertical still water shear forces are to be selected from those cases of flooding used in the damage stability calculations (see Section 36). cs = stress factor according to 1.1 QU = ultimate vertical shear force of the ship's transverse section [Kn] = q = number of shear force transmitting plate fields (in general, these are only the vertical plate fields of the ship's transverse section, e.g. shell and longitudinal bulkhead plate fields) 6Ji = reduction factor of the ith plate field according to Section 3, F.2.1. bi = breadth of the ith plate field [mm] ti = thickness of the ith plate field [mm] ReHi = minimum nominal yield point of the ith plate field [N/mm2 ] QUf = ultimate vertical shear force of the ship's undamaged transverse section [kN]. If no assumptions regarding the extent of damage are prescribed, QUf = 6dMQU, where 6dM is a reduction factor for the ultimate force in damaged conditions (6dM # 1). BKI - Rules for Hull - 2014
- 101. Section 5 - Longitudinal Strength D 5-19/27 D. Design Stresses 1. General Design stresses for the purpose of this rule are global load stresses, which are acting: – as normal stresses FL in ship's longitudinal direction : – for plates as membrane stresses – for longitudinal profiles and longitudinal girders in the bar axis – shear stresses JL in the plate level The stresses FL and JL are to be considered in the formulas for dimensioning of plate thicknesses (Section 6, B.1. and C.1. and Section 12, B.1.), longitudinals (Section 9, B.2.) and grillage systems (Section 8, B.8. and Section 10, E.2.). The calculation of the stresses can be carried out by an analysis of the complete hull. If no complete hull analysis is carried out, the most unfavourable values of the stress combinations according to Table 5.3 are to be taken for FL and JL respectively. The formulae in Table 5.3 contain FSW, FWV, FWH, FST and FWT according to 2. and JSW, JWV, JWH, JST and JWT according to 3. as well as: fF = weighting factor for the simultaneousness of global and local loads = 0,8 for dimensioning of longitudinal structures according to Sections 3 and 6 to 12 = for fatigue strength calculations according to Section 20 fQ = probability factor according to Table 4.2 fQmin = 0,75 for Q = 10-6 Note fQ is a function of the planned lifetime. For a lifetime of n > 20 years, fQ may be determined by the following formulae for a straight-line spectrum of seaway induced stress ranges : fQ = For greatest vertical wave bending moment: F’WV = J’WV = For smallest vertical wave bending moment : F’WV = J’WV = C = Note Forthepreliminarydeterminationofthescantlings,itisgenerallysufficienttoconsiderloadcase1,assumingthesimultaneous presence of FL1a and JL1b, but disregarding stresses due to torsion. The stress components (with the proper signs: tension positive, compression negative) are to be added such, that for FL and JL extreme values are resulting. 1.1 Buckling strength For structures loaded by compression or shear forces, sufficient buckling strength according to Section 3, F. is to be proved. BKI - Rules for Hull - 2014
- 102. D Section 5 - Longitudinal Strength5-20/27 1.2 Permissible stresses The equivalent stress from FL and JL is not to exceed the following value : FV = [N/mm2 ] Table 5.3 - Load cases and stress combinations Load Case Design stresses FL, JL L1a FL1a = JL1a = L1b FL1b = JL1b = L2a FL2a = JL2a = L2b FL2b = JL2b = L3a FL3a = JL3a = L3b FL3b = JL3b = L1a,b = Load caused by vertical bending and static torsional moment. L2a,b = Load caused by vertical and horizontal bending moment as well as static torsional moment. L3a,b = Load caused by vertical and horizontal bending moment as well as static and wave induced torsional moment 1.3 Structural design 1.3.1 Ingeneral,longitudinalstructures are tobedesignedsuch,thattheyrunthroughtransversestructures continuously. Major discontinuities have to be avoided. If longitudinal structures are to be staggered, sufficient shifting elements shall be provided. 1.3.2 TherequiredweldingdetailsandclassifyingofnotchesresultfromthefatiguestrengthanalysisaccordingtoSection 20. Within the upper and lower hull girder flange, the detail categories for the welded joints (see Table 20.3) shall not be less than )FR min = [N/mm2 ] MWVhog, MWVsag = vertical wave bending moment for hogging and sagging according to B.3.1 n = design lifetime of the ship 20 [years]≥ BKI - Rules for Hull - 2014
- 103. Section 5 - Longitudinal Strength D 5-21/27 2. Normal stresses in the ship's longitudinal direction 2.1 Normal stresses from vertical bending moments 2.1.1 statical from MSW : FSW = [N/mm2 ] MSW = still water bending moment according to A.5. at the position x/L 2.1.2 dynamical from MWV : FWV = [N/mm2 ] 2.2 Normal stresses due to horizontal bending moments dynamical from MWH : FWH = ! [N/mm2 ] MWH = horizontal wave bending moment according to B.3.3 at the position x/L Iz = moment of inertia[m4 ] of the transverse ship section considered around the vertical axis at the position x/L ey = horizontal distance of the structure considered from the vertical, neutral axis [m] ey is positive at the port side, negative at the starboard side 2.3 Normal stresses from torsion of the ship's hull When assessing the cross sectional properties the effect of wide deck strips between hatches constraining the torsion may be considered, e.g. by equivalent plates at the deck level having the same shear deformation as the relevant deck strips. 2.3.1 statical from MSTmax: For a distribution of the torsional moments according to B.2.2.2, the stresses can be calculated as follows : FST = [N/mm2 ] MSTmax = max. static torsional moment according to B.2.2.2 see 2.3.2. For other distributions the stresses have to be determined by direct calculations. 2.3.2 dynamical from MWTmax: FWT = [N/mm2 ] MWTmax = according to B.3.5 = for 0 # < 0,25CTor = for 0,25 # # 0,65 = for 0,65 # # 1 IT = sectorial inertia moment [m6 ] of the ship's transverse section at the position X/L BKI - Rules for Hull - 2014
- 104. D Section 5 - Longitudinal Strength5-22/27 Ti = sectorial coordinate [m2 ] of the structure considered 8 = warping value = [l/m] IT = torsional moment of inertia [m4 ] of the ship's transverse section at the position x/L e = Euler number (e = 2,718...) a = Rc = characteristical torsion length [m] = for < 5,284 = for > 5,284 Cc = for 0 # # 0,4 and 0 # # 0,4 = 1 for 0,4 # # 0,55 = for 0,55 < # 1 xA = 0 for ships without cargo hatches = distance [m] between the aft end of the length L and the aft edge of the hatch forward of the engine room front bulkhead on ships with cargo hatches, see also Fig. 5.13 3. Shear stresses Shear stress distribution shall be calculated by calculation procedures approved by BKI. For ships with multi-cell transverse cross sections (e.g. double hull ships), the use of such a calculation procedure, especially with non-uniform distribution of the load over the ship's transverse section, may be stipulated. 3.1 Shear stresses due to vertical shear forces For ships without longitudinal bulkheads or with two longitudinal bulkheads,the distribution of the shear stress in the shell and in the longitudinal bulkheads can be calculated with the following formulae: statical from QSW : JSW = dynamical from QWV : JWV = Sy(z)= first moment of the sectional area considered [m3 ], above or below, respectively, the level z considered, and related to the horizontal, neutral axis t = thickness of side shell or longitudinal bulkhead plating[mm] at the section considered " = 0 for ships having no longitudinal bulkhead If 2 (two) longitudinal bulkheads are arranged : " = 0,16 + 0,08 for the longitudinal bulkheads BKI - Rules for Hull - 2014
- 105. D, E Section 5 - Longitudinal Strength 5-23/27 = 0,34 - 0,08 for the side shell As = sectional area of side shell plating [m2 ] within the depth H AL = sectional area of longitudinal bulkhead plating [m2 ] within the depth H. For ships of normal shape and construction, the ratio S/Iy determined for the midship section can be used for all sections. 3.2 Shear stresses due to horizontal shear forces 3. is to be applied to correspondingly. 3.3 Shear stresses due to torsional moments statical from MSTmax : For a distribution of torsional moments according to B.2.2.2, the stresses can be calculated as follows: [N/mm2 ] CTor = according to D.2.3.1 MSTmax = according to B.2.2.2 MWTmax = according to B.3.5 IT = according to D.2.3.1 STi = statical sector moment [m4 ] of the structure considered ti = thickness[mm] of the plate considered For other distributions the stresses have to be determined by direct calculations. dynamical from MWTmax: = [N/mm2 ]τWT C M S I t Tor WT i i . . . max ω ω E. Permissible Still Water Loads 1. Vertical bending moments Thepermissiblestillwaterbendingmomentsforany sectionwithinthelengthLaretobedeterminedbythefollowingformulae: MSW = MT S MWV [kNm] MWV see B.3.1 For harbour- and offshore terminal conditions the wave loads may be multiplied with the following factors: — harbour conditions (normally) : 0,1 — offshore terminal conditions : 0,5 From the following two values for MT : MT = FD @ WD(a) @ [kNm] or MT = FB @ WB(a) @ [kNm] the smaller value is to be taken. WD(a), WB(a) = actual section modulus in the deck or bottom, respectively FD, F’D = longitudinal bending stress [N/mm2 ] for the ship’s upper hull girder flange BKI - Rules for Hull - 2014
- 106. E Section 5 - Longitudinal Strength5-24/27 = FSW + FWV FB = longitudinal bending stress [N/mm2 ] for the ship’s lower hull girder flange = FSW + FWV FSW, FWV longitudinal stress according to D.2. fr = 1,0 (in general). = according to F.2. for ships with large deck openings In the range x/L = 0,3 to x/L = 0,7 the permissible still water bending moment should generally not exceed the value obtained for x/L = 0,5. 2. Vertical shear forces ThepermissiblestillwatershearforcesforanycrosssectionwithinthelengthLaretobedeterminedbythefollowingformulae: QSW = QT S QWV [kN] QT = permissible total shear force [kN], for which the permissible shear stress J = JSW + JWV will be reached but not exceeded at any point of the section considered. J = permissible shear stress [N/mm2 ] QWV = according to B.3.2 For harbour and offshore terminal conditions, see 1. 2.1 Correction of still water shear force curve In casse with empty cargo hold, the conventional shear force curvemaybecorrected according to the direct load transmission by the longitudinal bottom structure at the transverse bulkheads. See also Fig. 5.12. 2.2 Thesupportingforcesofthebottomgrillageatthetransversebulkheadsmayeitherbedeterminedbydirect calculation or by approximation, according to 2.3. Fig. 5.12 Correction of the shear force curve 2.3 Thesumofthesupportingforcesofthebottomgrillageattheaftorforwardboundarybulkheadofthehold considered may be determined by the following formulae: )Q = u @ P S v @ T* [kN] P = mass of cargo or ballast [t] in the hold considered, including any contents of bottom tanks within the flat part of the double bottom T* = draught [m] at the centre of the hold u, v = correction coefficients for cargo and buoyancy as follows: u = [kN/t] BKI - Rules for Hull - 2014
- 107. Section 5 - Longitudinal Strength E, F 5-25/27 v = 10 @ 6 @ R @ b [kN/m] 6 = R = length of the flat part of the double bottom [m] b = breadth of the flat part of the double bottom [m] h = height of the hold [m] V = volume of the hold [m3 ]. 3. Static torsional moments The permissible static torsional moments have to be determined on the basis of the design stresses in Table 5.3. together with the formula in D.2.3.1. 3.1 For ships with torsional moments according to B.2. it has to be proved by means of the loading computer, that the maximum permissible values are exceeded at no location. Excess values are permissible, if the actual torsional moments at the adjacent calculation points are correspondingly less than the permissible values. 3.2 Unless shown by a particular proof, during loading and unloading the static torsional moments shall not be higher than 75 % of the wave induced torsional moment according to B.3.5. F. Guidance Values for Large Deck Openings 1. General 1.1 Displacements of the upper hull girder flange mainly caused by torsional loads, induce additional local bending moments and forces acting in the deck strips. These moments act about the z-axis, see Fig. 5.1. After consultation with BKI stresses resulting from that have to be calculated for longitudinal and transverse girders and to be taken into account for the design. The calculation of these stresses can be dispensed with, if the guidance values according to 2. and 3. are observed. 1.2 A ship is regarded as one with large deck openings if one of the following conditions applies to one or more hatch openings: .1 > 0,6 .2 > 0,7 bL = breadth of hatchway, in case of multi hatchways, bL is the sum of the individual hatchway-breadths RL = length of hatchway BM = breadth of deck measured at the mid length of hatchway RM = distancebetweencentresoftransversedeckstripsateachendofhatchway.Wherethereisnofurtherhatchway beyond the one under consideration, RM will be specially considered. 2. Guidance values for the determination of the section modulus The section moduli of the transverse sections of the ship are to be determined according to C.1. and C.2. The factor fr amounts to: according to D. for the ship's upper respectively lower girder. The greater value is to be taken.σ σ σL SW WV1, , The calculation of the factor fr may be dispensed with, if fr is selected according to Fig. 5.13. BKI - Rules for Hull - 2014
- 108. F Section 5 - Longitudinal Strength5-26/27 Fig. 5.13 - Correction factor fr and distribution factor cu 3. Guidance values for the design of transverse box girders of container ships The scantlings of the transverse box girders are to be determined by using the following design criteria : – support forces of hatch covers, see Section 17, B.4.5 - B.4.7. – support forces of the containers stowed in the hold place (e.g. due to longitudinal acceleration) – stresses due to the torsional deformations of the hull, – stresses resulting from the water pressure, if the transverse box girder forms part of a watertight bulkhead, see Section 11. In general the plate thickness shall not be less than obtained from the following formulae (see also Fig. 5.14) : t1 = [mm] : or t1 = 0,5 t0 [mm] t0 = thickness of longitudinal hatch coaming or of the uppermost strake of the longitudinal bulkhead t2 = 0,85 [mm] : or t2 = 12 @ a [mm] a = spacing of stiffeners [m]. The larger of the values t1 or t2 is to be taken. L need not be taken greater than 200 m. For coamings on the open deck see also Section 17, B.1. Fig. 5.14 Plate thickness of the transverse box girder BKI - Rules for Hull - 2014
- 109. Section 5 - Longitudinal Strength F, G 5-27/27 4. Guidance values for the displacements of the upper girder of the ship Ingeneral,therelativedisplacement)ubetweentheshipsidesistobedetermined bydirectcalculations.Forthedimensioning of hatch cover bearings and seals, the following value may be used for the displacement: = [mm]Δu MSTmax, MWTmax according to B.2.2.2 or B.3.5, respectively cu = distribution factor according to Fig. 5.13 cA = value for cu at the aft part of the open region, see also Fig. 5.13 = xA = according to D.2.3.1; for xA no smaller value than 0,15 L and no greater value than 0,3 L is to be taken. G. Bulk Carriers 1. General In addition to the requirements of B., for all bulk carriers with the Notation BC-A or BC-B according to Section 23, F.2.1, the longitudinal strength is to be checked to be adequate for specified flooded conditions, in each of the cargo and ballast conditions considered in the intact longitudinal strength calculations. The loading conditions ''harbour'', ''docking, afloat'', ''loading and unloading transitory conditions'' as well as ''ballast water exchange'' need not be considered. The required moment of inertia according to C.3. and the strength of local structural members are excluded from this proof. For accessibility see Section 1, D.1. 2. Flooding criteria To calculate the weight of ingressing water, the following assumptions are to be made: – The permeability of empty cargo spaces and volume left in loaded cargo spaces above any cargo is to be taken as 0,95. – Appropriatepermeabilitiesandbulkdensitiesaretobeusedforanycargocarried.Forironore,aminimum permeability of 0,3 with a corresponding bulk density of 3,0 t/m3 is to be used. For cement, a minimum permeability of 0,3 with a corresponding bulk density of 1,3 t/m3 is to be used. In this respect, "permeability" for solid bulk cargo means the ratio of the floodable volume between the cargo parts to the gross volume of the bulk cargo. – For packed cargo conditions (such as steel mill products), the actual density of the cargo should be used. The permeability has to be harmonized case by case (pipes, flat steel, coils etc.) with BKI. 3. Flooding conditions Each cargo hold is to be considered individually flooded up to the equilibrium waterline. This does not apply for cargo holds of double hull construction where the double hull spacing exceeds 1 000 mm, measured vertically to the shell at any location of the cargo hold length. The wave induced vertical bending moments and shear forces in the flooded conditions are assumed to be equal to 80 % of the wave loads, as given in B.3.1. and B.3.2. BKI - Rules for Hull - 2014
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- 111. Section 6 - Shell Plating A, B 6-1/20 Section 6 Shell Plating A. General, Definitions 1. General 1.1 Theapplicationofthedesignformulae giveninB.1.2andC.1.2toships ofless than90minlengthmaybeaccepted when a proof of longitudinal strength has been carried out. 1.2 Theplatethicknessesaretobetaperedgradually,ifdifferent.Gradualtaperisalsotobeeffectedbetweenthethicknesses required for strengthening of the bottom forward as per E.2. and the adjacent thicknesses. 2. Definitions k = material factor according to Section 2, B.2. pB, pB1 = load on bottom [kN/m2 ] according to Section 4, B.3. ps, ps1 = load on sides [kN/m2 ] according to Section.4, B.2.1 pe = design pressure for the bow area [kN/m2 ] according to Section 4, B.2.2 or according to Section 4, B.2.3 for the stern area as the case may be pSL = design slamming pressure [kN/m2 ] according to Section 4, B.4. nf = 1,0 for transverse framing = 0,83 for longitudinal framing FLB = Maximum bottom design hull girder bending stress [N/mm2 ] according to Section 5, D.1. FLS = maximumdesignhullgirderbendingstressinthesideshellatthestationconsideredaccordingtoSection 5, D.1. [N/mm2 ]. JL = maximum design shear stress due to longitudinal hull girder bending [N/mm2 ], according to Section 5, D.1. Fperm= permissible design stress [N/mm2 ] = [N/mm2 ] for L < 90 m = [N/mm2 ] for L 90 m tK = corrosion addition according to Section 3, K. B. Bottom Plating 1. Plate thickness based on load stress criteria 1.1 Ships with lengths L < 90 m The thickness of the bottom shell plating within 0,4 L amidships is not to be less than : tB1 = [mm] Within0,1LforwardoftheaftendofthelengthLandwithin 0,05L aft of F.P. the thickness is not to beless thantB2 according to 1.2. 1.2 Ships with length L > 90 m The thickness of the bottom plating is not to be less than the greater of the two following values : BKI - Rules for Hull - 2014
- 112. B Section 6 - Shell Plating6-2/20 tB1 = [mm] tB2 = [mm] FPR = [N/mm2 ] Note : As a first approximation FLB and JL may be taken as follows: FLB = [N/mm2 ] for L < 90 m = [N/mm2 ] for L 90 m JL = 0 2. Critical plate thickness, buckling strength 2.1 Guidance values for critical plate thickness For ships, for which proof of longitudinal strength is required or carried out respectively, the following guidance values for the critical plate thickness are recommended: for FLB 0,6 @ ReH : tcrit = [mm] for FLB > 0,6 @ ReH : tcrit = [mm] c = 0,5 for longitudinal framing = for transverse framing " = aspect ratio a/b of plate panel considered (see Section 3, F. 1.) FLB = largest compressive stress in the bottom due to longitudinal hull girder bending Fl = see Section 3, F.1. (Table 3.2) = 1,0 for longitudinal framing. 2.2 Buckling strength Theguidancevaluesobtainedfrom2.1aretobeverifiedaccordingtoSection3,F.Section5,C.6.applieswheresolelylongitudinal hull girder bending stress need to be considered. Section 8, B.8. applies where the combined action of longitudinal hull girder bending and local loads has to be considered. 3. Minimum thickness At no point the thickness of the bottom shell plating shall be less than : tmin = [mm] for L < 50 m = [mm] for L 50 m tmax = 16,0 mm in general or bulk carriers see Section 23, B.5.3, for tankers see Section 24, A.14. 4. Bilge strake 4.1 The thickness of the bilge strake is to be determined as required for the bottom plating according to 1. The thickness so determined is to be verified for sufficient buckling strength according to the requirements of Section 5, C.6.. and Section 3, F., see Table 3.4, load cases 1a, 1b, 2 and 4. BKI - Rules for Hull - 2014
- 113. Section 6 - Shell Plating B 6-3/20 If this verification shows that a smaller thickness than that of the bottom plating is possible, such smaller thickness may be permitted. 4.2 If according to Section 2, B. a higher steel grade than A/AH is required for the bilge strake, the width of the bilge strake is not to be less than: b = 800 + 5 @ L [mm] 4.3 At the end of the curved bilge strake longitudinal stiffeners or girders are to be arranged. When the stiffeners are arranged outside the bilge radius sufficient buckling resistance according to Section 3, F. is to be shown for the plane plate fields taking into account the stresses according to Section 5, D.1 and the compression stresses Fq = [N/mm2 ] acting coincidently in the transverse direction. The thickness of these plate fields shall not be less than the thickness derived from 1., 3. and C.1. respectively. For the frame spacing a and the field length R, aL and bL + R/4 are to be taken accordingly, see sketch. aL = spacing of the floors or transverse stiffeners respectively [mm] bL = distance of the longitudinal stiffener from the end of corner radius [mm] R = bilge radius [mm] p = ps, ps1 or pB1 at the end of corner radius or pSL according to Section 4, B.4.1 as the case may be [kN/m2 ]. t = plate thickness [mm] Ifthederivedthicknessfortheplaneplatefield is larger than that for the curved bilge strake accordingto4.1thereinforcement is to be expanded by a minimum of R/6 into the radius. 5. Flat plate keel and garboard strake 5.1 The width of the flat plate keel is not to be less than: b = 800 + 5 @ L [mm] The thickness of the flat plate keel is not to be less than: tFK = tB + 2,0 [mm] within 0,7 L amidships and in way of the engine seating = tB [mm] otherwise BKI - Rules for Hull - 2014
- 114. B, C Section 6 - Shell Plating6-4/20 tB = thickness of the bottom plating [mm] according to 1. – 3. 5.2 Forshipsexceeding100minlength,thebottomofwhichislongitudinallyframed,theflatplatekeelistobestiffened byadditionallongitudinalstiffenersfittedatadistanceofapprox.500mmfromcentreline.Thesectionalareaofonelongitudinal stiffener should not be less than 0,2 L [cm2 ]. 5.3 Where a bar keel is arranged, the adjacent garboard strake is to have the scantlings of a flat plate keel. C. Side Shell Plating 1. Plate thickness based on load stress criteria 1.1 Ships with lengths L < 90 m The thickness of the side shell plating within 0,4 L amidship is not to be less than: tS1 = [mm] Within0,1LforwardoftheaftendofthelengthLandwithin0,05 L aft of F.P. the thickness is not to be less than tS2 according to 1.2. 1.2 Ships with lengths L 90 m The thickness of the side shell plating is not to be less than the greater of the following values: tS1 = [mm] tS2 = [mm] tS3 = [mm] FpR = [N/mm2 ] FpRmax= [N/mm2 ] p = ps or pe as the case may be Note : As a first approximation FLS and JL may be taken as follows: FLS = 0,76 @ FLB [N/mm2 ] JL = [N/mm2 ] FLB = see B.1.2. 1.3 In way of large shear forces, the shear stresses are to be checked in accordance with Section 5,D. 2. Minimum thickness For the minimum thickness of the side shell plating B.3. applies accordingly. Abovealevel T+c0/2abovebaselinesmallerthicknessesthan tmin may be accepted if the stress level permits such reduction. For c0 see Section 4, A.2.2. BKI - Rules for Hull - 2014
- 115. Section 6 - Shell Plating C 6-5/20 3. Sheerstrake 3.1 The width of the sheerstrake is not to be less than: b = 800 + 5 @ L [mm] bmax = l800 [mm] 3.2 The thickness of the sheerstrake shall, in general, not be less than the greater of the following two values: t = 0,5 (tD + tS) [mm] = tS [mm] tD = required thickness of strength deck tS = required thickness of side shell. 3.3 Where the connection of the deck stringer with the sheerstrake is rounded, the radius is to be at least 15 times the plate thickness. 3.4 Welds on upper edge of sheerstrake are subject to special approval. Regarding welding between sheerstrake and deck stringer see Section 7, A.2. Holes for scuppers and other openings are to be carefully rounded, any notches shall be avoided. 4. Buckling strength For ship for which proof of longitudinal strength is required or carried out proof of buckling strength of the side shell is to be provided in accordance with the requirements of Section 5, C.6. and Section.3,.F. 5. Strengthenings for harbour and tug manoeuvres 5.1 In those zones of the side shell which may be exposed to concentrated loads due to harbour manoeuvres the plate thickness is not to be less than required by 5.2. These zones are mainly the plates in way of the ship's fore and aft shoulder. The exact locations where the tugs shall push are to be defined in the building specification. They are to be identified in the shell expansion plan. The length of the strengthened areas shall not be less tha n approximately 5 m. The height of the strengthened areas shall extend from about 0,5 m above ballast waterline to about 4,0 m above load water line. Forshipsof100minlengthandoveratleastonestrengthenedareaistobeprovidedamidshipsinadditiontothetwostrengthened areas at the ship's shoulders. Where the side shell thickness so determined exceeds the thickness required by 1. - 3. it is recommended to specially mark these areas. 5.2 The plate thickness in the strengthened areas is to be determined by the following formulae: t = [mm] PfR = local design impact force [kN] = D/100 [kN] with a minimum of 200 kN and a maximum of 1000 kN D = displacement of the ship [t]. Any reductions in thickness for restricted service are not permissible. 5.3 In the strengthened areas the section modulus of side longitudinals is not to be less than: W = [cm3 ] R = unsupported span of longitudinal [m]. 5.4 Tween decks, transverse bulkheads, stringer and transverse walls are to be investigated for sufficient buckling strengthagainstloadsactingintheship's transversedirection. For scantlings of side transverses supporting side longitudinals see Section 9, B.4.4. BKI - Rules for Hull - 2014
- 116. D, E Section 6 - Shell Plating6-6/20 D. Side Plating of Superstructures 1. The side plating of effective superstructures is to be determined according to C. 2. The side plating of non-effective superstructures is to be determined according to Section 16. 3. For the definition of effective and non-effective superstructures see Section 16, A.1. For strengthening at ends of superstructures see Section.16, A.3. E. Strengthening of Bottom Forward 1. Arrangement of floors and girders 1.1 For the purpose of arranging floors and girders the following areas are defined: ! forward of for L 100 m ! forward of for 100 < L 150 m ! forward of for L > 150 m 1.2 In case of transverse framing, plate floors are to be fitted at every frame. Where the longitudinal framing system or the longitudinal girder system is adopted the spacing of plate floors may be equal to three transverse frame spaces. 1.3 In case of transverse framing, the spacing of side girders is not to exceed L/250 + 0,9 [m], up to a maximum of 1,4 m. In case of longitudinal framing, the side girders are to be fitted not more than two longitudinal frame spacings apart. 1.4 Distances deviating from those defined in 1.2 and 1.3 may be accepted on the basis of direct calculations. 1.5 Within the areas defined in 1.1 any scalloping is to be restricted to holes for welding and for limbers. 2. Bottom plating forward of = 0,5 2.1 The thickness of the bottom plating of the flat part of the ship's bottom up to a height of 0,05 @ Tb or 0,3 m above base line, whichever is the smaller value, is not to be less than: t = 0,9 @ f2 @ a + tK [mm] Tb = smallest design ballast draft at the forward perpendicular [m]. f2 = see Section 3, A.3. 2.2 Above0,05Tb or 0,3m abovebaselinetheplatethicknessmaygraduallybetaperedtotherulethicknessdetermined according to B. For ships with a rise of floor the strengthened plating shall at least extend to the bilge curvature. 3. Stiffeners forward of 3.1 The section modulus of transverse or longitudinal stiffeners is not to be less than: W = 0,155 @ pSL @ a @ R2 @ k [cm3 ]. 3.2 The shear area of the stiffeners is not to be less than: A = 0,028 @ pSL @ a (R n 0,5 @ a) k [cm2 ]. The area of the welded connection has to be at least twice this value. BKI - Rules for Hull - 2014
- 117. Section 6 - Shell Plating F,G 6-7/20 F. Strengthenings in Way of Propellers and Propeller Shaft Brackets, Bilge Keels 1. Strengthenings in way of propellers and propeller brackets 1.1 The thickness of the shell plating in way of propellers is to be determined according to C. Note It is recommended that plate fields and stiffenersofshell structures inthevicinityofthepropeller(s)bespeciallyconsidered from a vibration point of view (see also Section 8, A.1.2.1 and Section 12, A.8). For vessels with a single propeller, plate fields and stiffeners within dr = 3 should fulfil the following frequency criteria: for " $ 60E : for " < 60E : " = flareangleofframesectioninpropeller planemeasured between a vertical line andthetangentto the bottom shell plating fplate = lowestnaturalfrequencyofisotropicplatefieldunderconsiderationofadditionaloutfitting and hydrodynamic masses [Hz] fstiff = lowest natural frequency of stiffener under consideration of additional outfitting and hydrodynamic masses [Hz] dr = ratio r = distance of plate field or stiffener to 12 o'clock propeller blade tip position [m] dp = propeller diameter [m] fblade = propeller blade passage excitation frequency at n [Hz] = [Hz] n = maximum propeller shaft revolution rate [1/min] z = number of propeller blades 1.2 In way of propeller shaft brackets, Section 19, B.4.3 has to be observed 1.3 Wherepropellerrevolutionsareexceeding300rpm(approx.),particularlyincaseofflatbottomsintercostalcarlings are to be fitted above or forward of the propeller in order to reduce the size of the bottom plate panels (see also Section 8, A. 1.2.3.4). 2. Bilge keels 2.1 Where bilge keels are provided they are to be welded to continuous flat bars, which are connected to the shell plating with their flat side by means of a continuous watertight welded seam, see bottom of Fig. 6.1. 2.2 The ends of the bilge keels are to have soft transition zones according to Fig. 6.1, top. The ends of the bilge keels shall terminate above an internal stiffening element. 2.3 Any scallops or cut-outs in the bilge keels are to be avoided. G. Openings in the Shell Plating 1. General 1.1 Where openings are cut in the shell plating for windows or side scuttles, hawses, scuppers, sea valves etc., they BKI - Rules for Hull - 2014
- 118. G, H Section 6 - Shell Plating6-8/20 are to have well rounded corners. If they exceed 500 mm in width in ships up to L = 70 m, and 700 mm in ships having a length L of more than 70 m, the openings are to be surrounded by framing, a thicker plate or a doubling. 1.2 Aboveopeningsinthe sheerstrake within 0,4L amidships, generally a strengthenedplateoracontinuousdoubling is to be provided compensating the omitted plate sectional area. For shell doors and similar large openings see J. Special strengthening is required in the range of openings at ends of superstructures. 1.3 The shell plating in way of the hawse pipes is to be reinforced. 2. Pipe connections at the shell plating Scupper pipes and valves are to be connected to the shell by weld flanges. Instead of weld flanges short flanged sockets of adequate thickness may be used if they are welded to the shell in an appropriate manner. Reference is made to Section 21, D. Construction drawings are to be submitted for approval. Fig 6.1 Soft transition zones at the ends of bilge keels H. Bow Doors and Inner Doors 1. General, definitions 1.1 Applicability 1.1.1These requirements apply to the arrangement, strength and securing of bow doors and inner doors leading to a complete or long forward enclosed superstructure, or to a long non-enclosed superstructure, where fitted to attain minimumbowheight equivalence. The requirements apply to all ro-ro passenger ships and ro-ro cargo ships engaged on international voyages and also to ro-ro passengershipsandro-rocargoshipsengagedonlyindomestic(non-international)voyages,exceptwherespecificallyindicated otherwise herein. BKI - Rules for Hull - 2014
- 119. Section 6 - Shell Plating H 6-9/20 The requirements are not applicable to high speed, light displacement craft as defined in the IMO Code of Safety for High Speed Craft. 1.1.2 Two types of bow door are covered by these requirements: S Visor doors opened by rotating upwards and outwards about a horizontal axis through two or more hinges located near the top of the door and connected to the primary structure of the door by longitudinally arranged lifting arms. S Side-opening doors opened either by rotating outwards about a vertical axis through two or more hinges located near the outboard edges or by horizontal translation by means of linking arms arranged with pivoted attachments to the door and the ship. It is anticipated that side-opening bow doors are arranged in pairs. Other types of bow door will be specially considered in association with the applicable requirements of these Rules. 1.2 Arrangement 1.2.1Bow doors are to be situated above the free-board deck. A watertight recess in the freeboard deck located forward of the collision bulkhead and above the deepest waterline fitted for arrangement of ramps or other related mechanical devices, may be regarded as a part of the freeboard deck for the purpose of this requirement 1.2.2An inner door is to be provided. The inner door is to be part of the collision bulkhead. The inner door needs not be fitted directly above the collision bulkhead below, provided it is located within the limits specified in Section 11, A.2.1 for the position of the collision bulkhead. A vehicle ramp may be arranged for this purpose, provided its position complies with Section 11, A.2.1. If this is not possible, a separate inner weatherthight door is to be installed, as far as practicable within the limits specified for the position of the collision bulkhead. 1.2.3Bowdoors are tobe so fittedastoensuretightnessconsistentwithoperationalconditionsandtogiveeffective protection to inner doors. Inner doors forming part of the collision bulkhead are to be weathertight over the full height of the cargo space and arranged with fixed sealing supports on the aft side of the doors. 1.2.4Bow doors and inner doors are to be so arranged as to preclude thepossibilityofthe bowdoor causing structuraldamage to the inner door or to the collision bulkhead in the case of damage to or detachment of the bow door. If this is not possible, a separate inner weathertight door is to be installed, as indicated in 1.2.2. 1.2.5Therequirementsforinnerdoorsarebasedontheassumptionthatthevehiclesareeffectivelylashedandsecuredagainst movement in stowed position. 1.3 Definitions Securing device is a device used to keep the door closed by preventing it from rotating about its hinges. Supporting device is a device used to transmit external or internal loads from the door to a securing device and from the securing device to the ship’s structure, or a device other than a securing device, such as a hinge, stopper or other fixed device, that transmits loads from the door to the ship’s structure. Locking device is a device that locks a securing device in the closed position. 2. Strength criteria 2.1 Primary structure and securing and supporting devices 2.1.1Scantlings of the primary members, securing and supporting devices of bow doors and inner doors are to be so designed that under the design loads defined in 3. the following stresses are not exceeded: bending stress: F = [N/mm2 ] shear stress: J = [N/mm2 ] equivalent stress: Fv = [N/mm2 ] where k is the material factor as given in Section 2, B.2.1, but is not to be taken less than 0,72 unless a fatigue analysis is carried out according to Section 20. BKI - Rules for Hull - 2014
- 120. H Section 6 - Shell Plating6-10/20 2.1.2The buckling strength of primary members is to be verified according to Section 3, F. 2.1.3For steel to steel bearings in securing and supporting devices, the nominal bearing pressure calculated by dividing the design force by the projected bearing area is not to exceed 0,8 x ReH, where ReH is the yield stress of the bearing material. Forotherbearingmaterials,thepermissiblebearingpressureistobedeterminedaccordingtothemanufacturer’sspecification. 2.1.4The arrangement of securing and supporting devices is to be such that threaded bolts do not carry support forces. The maximum tension stress in way of threads of bolts not carrying support forces is not to exceed 125/k [N/mm2 ]. 3. Design loads 3.1 Bow doors 3.1.1The design external pressure to be considered for the scantlings of primary members of bow doors is not to be less than the pressure specified in Section 4, B.2, but is not to be taken less than : pe = @ [kN/m2 ] vo = ship's speed [kn] as defined in Section 1, H.5 L = ship's length [m], L 200 m cRW = service range coefficient according to Section.4, A.2.2 cH = for L < 80 m = 1,0 for L 80 m " = flare angle at the point to be considered, defined as the angle between a vertical line and the tangent to the side shell plating, measured in a vertical plane normal to the horizontal tangent to the shell plating $ = entryangleatthepointtobeconsidered,definedastheanglebetweenalongitudinallineparalleltothecentreline and the tangent to the shell plating in a horizontal plane. See also Fig. 6.2. Fig. 6.2 Definition angles " and $ 3.1.2The design external forces for determining scantlings of securing and supporting devices of bow doors are not to be less than : Fx = [kN] Fy = [kN] BKI - Rules for Hull - 2014
- 121. Section 6 - Shell Plating H 6-11/20 Fz = [kN] Ax = area [m2 ] of the transverse vertical projection of the door between the levels of the bottom of the door and the upper deck or between the bottom of the door and the top of the door, whichever is the lesser, Ay = area [m2 ] of the longitudinal vertical projection of the door between the levels of the bottom of the door and the upper deck or between the bottom of the door and the top of the door, whichever is the lesser, Az = area [m2 ] of the horizontal projection of the door between the levels of the bottom of the door and the upper deck or between the bottom of the door and the top of the door, whichever is the lesser, for Ax , Ay and Az see also Fig. 6.3. h = height[m] of the door between the levels of the bottom of the door and the upper deck or between the bottom of the door and the top of the door, whichever is the lesser, R = length [m] of the door at a height h/2 above the bottom of the door, pe = external design pressure [kN/m2 ] as given in 3.1.1 with angles " and $ defined as follows: " = flare angle measured at the point on the bow door, R/2 aft of the stem line on the plane h/2 above the bottom of the door, as shown in Fig. 6.2. $ = entry angle measured at the same point as ". For bow doors, including bulwark, of unusual form or proportions, e.g. ships with a rounded nose and large stem angles, the areas and angles used for determination of the design values of external forces may require to be specially considered. 3.1.3For visor doors the closing moment My under external loads is to be taken as: My = [kN m] W = mass of the visor door [t] a = vertical distance [m] from visor pivot to the centroid of the transverse vertical projected area Ax of the visor door, as shown in Fig.6.3 b = horizontal distance[m] from visor pivot to the centroid of the horizontal projected area Az of the visor door, as shown in Fig. 6.3 c = horizontal distance[m] from visor pivot to the centre of gravity of visor mass, as shown in Fig. 6.3. Fig. 6.3 Bow door of visor type 3.1.4Moreover,theliftingarmsofavisordooranditssupportsareto be dimensioned for the staticanddynamicforcesapplied during the lifting and lowering operations, and a minimum wind pressure of 1,5 kN/m2 is to be taken into account. BKI - Rules for Hull - 2014
- 122. H Section 6 - Shell Plating6-12/20 3.2 Inner doors 3.2.1The design external pressure pe considered for the scantlings of primary members, securing and supporting devices and surrounding structure of inner doors is to be taken as the greater of the following: ! pe = 0,45 @ L [kN/m2 ] or ! hydrostatic pressure ph = 10 @ h [kN/m2 ], where h is the distance [m] from the load point to the top of the cargo space Where L is the ship's length, as defined in 3.1.1. 3.2.2The design internal pressure pi considered for the scantlings of securing devices of inner doors is not to be less than: pi = 25 [kN/m2 ] 4. Scantlings of bow doors 4.1 General 4.1.1The strength of bow doors is to be commensurate with that of the surrounding structure. 4.1.2Bow doors are to be adequately stiffened and means are to be provided to prevent lateral or vertical movement of the doorswhenclosed.Forvisordoorsadequatestrengthfortheopeningandclosingoperationsistobeprovidedintheconnections of the lifting arms to the door structure and to the ship structure. 4.2 Plating and secondary stiffeners 4.2.1The thickness of the bow door plating is not to be less than the side shell thickness tS2 according to C.1.2, using bow door stiffener spacing, but in no case less than the required minimum thickness of the shell plating according to C.2. 4.2.2The section modulus of horizontal or vertical stiffeners is not to be less than that required for framing at the position ofthedooraccordingtoSection9.Considerationis tobe given, wherenecessary,todifferencesinfixitybetweenship'sframes and bow doors stiffeners. 4.2.3The stiffener webs are to have a net sectional area not less than : Aw = [cm2 ] Q = shearforce[kN] in the stiffener calculated by usinguniformlydistributedexternaldesignpressurepe asgiven in 3.1.1 4.3 Primary structure 4.3.1The bow door secondary stiffeners are to be supported by primary members constituting the main stiffening of the door. 4.3.2The primary members of the bow door and the hull structure in way are to have sufficient stiffness to ensure integrity of the boundary support of the door. 4.3.3Scantlings of the primary members are generally to be verified by direct calculations in association with the external design pressure given in 3.1.1 and permissible stresses given in 2.1.1. Normally, formulae for simple beam theory may be applied. 5. Scantlings of inner doors 5.1 General 5.1.1Fordeterminingscantlingsoftheprimarymemberstherequirementsof4.3.3applyinconjunctionwiththeloadsspecified in 3.2. 5.1.2Where inner doors also serve as vehicle ramps, the scantlings are not to be less than those required for vehicle decks as per Section 7, B.2. 5.1.3Thedistributionoftheforcesactingonthesecuringandsupportingdevicesisgenerallytobeverifiedbydirectcalculations BKI - Rules for Hull - 2014
- 123. Section 6 - Shell Plating H 6-13/20 taking into account the flexibility of the structure and the actual position and stiffness of the supports. 6. Securing and supporting of bow doors 6.1 General 6.1.1Bow doors are to be fitted with adequate means of securing and supporting so as to be commensurate with the strength and stiffness of the surrounding structure. The hull supporting structure in way of the bow doors is to be suitable for the same design loads and design stresses as the securing and supporting devices. Where packing is required, the packing material is to be of a comparatively soft type, and the supporting forces are to be carried by the steel structure only. Other types of packing may be considered. The maximum design clearance between securing and supporting devices is generally not to exceed 3 mm. A means is to be provided for mechanically fixing the door in the open position. 6.1.2Only the active supporting and securing devices having an effective stiffness in the relevant direction are to be included and considered to calculate the reaction forces acting on the devices. Small and/or flexible devices such as cleats intended to provide load compression of the packing material are not generally to be included in the calculations called for in 6.2.5. The number of securing and supporting devices are generally to be the minimum practical whilst taking into account the redundancy requirements given in 6.2.6 and 6.2.7 and the available space for adequate support in the hull structure. 6.1.3Foropeningoutwardsvisordoors,thepivotarrangementisgenerallytobesuchthatthevisorisselfclosingunderexternal loads, that is My > 0. Moreover, the closing moment My as given in 3.1.3 is to be not less than: My0 = [kNm] 6.2 Scantlings 6.2.1Securing and supporting devices are to be adequately designed so that they can withstand the reaction forces within the permissible stresses given in 2.1.1. 6.2.2For visor doors the reaction forces applied on the effective securing and supporting devices assuming the door as a rigid body are determined for the following combination of external loads acting simultaneously together with the self weight of the door: Case 1 : Fx and Fz , Case 2 : 0,7 @ Fy acting on each side separately together with 0,7 @ Fx and 0,7 @ Fz . The forces Fx , Fy and Fz are to be determined as indicated in 3.1.2 and applied at the centroid of the projected areas. 6.2.3For side-opening doors the reaction forces applied on the effective securing and supporting devices assuming the door as a rigid body are determined for the following combination of external loads acting simultaneously together with the self weight of the door: Case 1 : Fx , Fy and Fz acting on both doors Case 2 : 0,7 @ Fx and 0,7 @ Fz acting on both doors and 0,7 @ Fy acting on each door separately, for Fx , Fy and Fz see 6.2.2. 6.2.4Thesupportforcesasdeterminedaccordingto6.2.2and6.2.3shallgenerallyresultinazeromomentaboutthetransverse axis through the centroid of the area Ax . For visor doors, longitudinal reaction forces of pin and/or wedge supports at the door base contributing to this moment are not to be of the forward direction. 6.2.5The distribution of the reaction forces acting on the securingand supporting devices may require to be verified by direct calculations taking into account the flexibility of the hull structure and the actual position and stiffness of the supports. This is, for instance, the case when the bow door is supported statically undetermined. 6.2.6The arrangement of securing and supporting devices in way ofthese securing devices istobedesigned with redundancy so that in the event of failure of any single securing or supporting device the remaining devices are capable of withstanding the reaction forces without exceeding by more than 20% the permissible stresses as given in 2.1. BKI - Rules for Hull - 2014
- 124. H Section 6 - Shell Plating6-14/20 6.2.7For visor doors, two securing devices are to be provided at the lower part of the door, each capable of providing the fullreactionforce required to prevent opening of the door withinthe permissible stresses given in 2.1.1. The opening moment M0 to be balanced by this reaction force, is not to be taken less than the greater of the following values: M01 = [kNm] M02 = [kNm] FH = horizontal design force [kN], acting forward in the centre of gravity, FH = 10 × W d = vertical distance [m] from the hinge axis to the centre of gravity of the door mass, as shown in Fig. 6.3 )x = lever = 0,25 × e [m] e = distance[m] as defined in Fig. 6.3 a = distance[m] as defined in 3.1.3 6.2.8Forvisordoors,thesecuringandsupportingdevicesexcludingthehingesaretobecapableofresistingtheverticaldesign force Fv = Fz – 10 × W [kN] within the permissible stresses given in 2.1.1. 6.2.9All load transmitting elements in the design load path, from door through securing and supporting devices into the ship structure, including welded connections, are to be of the same strength standard as required for the securing and supporting devices. 6.2.10 For side-opening doors, thrust bearings are to be provided in way of girder ends at the closing of the two leaves to prevent one leaf to shift towards the other one under effect of unsymmetrical pressure. An example for a thrust bearing is shown in Fig. 6.4. Securing devices are to be provided so that each part of the thrust bearing can be kept secured on the other part. Any other arrangement serving the same purpose may be accepted. Fig. 6.4 Thrust bearing 7. Arrangement of securing and locking devices 7.1 Systems for operation 7.1.1Securing devices are to be simple to operate and easily accessible. Securing devices are to be equipped with mechanical locking arrangement (self locking or separate arrangement), or to be of the gravity type. The opening and closing systems as well as securing and locking devices are to be interlocked in such a way that they can only operate in the proper sequence. 7.1.2Bow doors and inner doors giving access to vehicle decks are to be provided with an arrangement for remote control, from a position above the freeboard deck of: ! the closing and opening of the doors, and ! associated securing and locking devices for every door. Indication of the open/closed position of every securing and locking device is to be provided at the remote control stations. BKI - Rules for Hull - 2014
- 125. Section 6 - Shell Plating H 6-15/20 The operating panels for operation of doors are to be inaccessible to unauthorized persons. A notice plate, giving instructions to the effect that all securing devices are to be closed and locked before leaving harbour, is to be placed at each operating panel and is to be supplemented by warning indicator lights. 7.1.3Where hydraulic securing devices are applied, the systemis to be mechanically lockable in closed position. This means that, in the event of loss of the hydraulic fluid, the securing devices remain locked. The hydraulic systemfor securing and locking devices is to beisolated fromother hydraulic circuits, wheninclosed position. 7.2 Systems for indication/monitoring The requirements according to 7.2.3 – 7.2.6 are only for ships – with or without passengers – with Ro-Ro spaces as defined in Chapter II-2, Regulation 3 of SOLAS 74. 7.2.1Separate indicator lights are to be provided on the navigation bridge and on the operating panel to show that the bow doorandinnerdoorareclosedandthattheirsecuringandlockingdevicesareproperly positioned. Deviations fromthe correct closing state are to be indicated by acustic and visual alarms. The indication panel is to be provided with a lamp test function. It shall not be possible to turn off the indicator lights. 7.2.2The indicator systemis to be designed on the self-monitoring principle and is to be alarmed by visual and audible means if the door is not fully closed and not fully locked or if securing devices become open or locking devices become unsecured. The power supply for the indicator system is to be independent of the power supply for operating and closing doors. The sensors of the indicator system are to be protected from water, ice formation and mechanical damages. Degree of protection: at least IP 56. Note: The indicator system is considered designed on the fail - safe principal when : 1) The indication panel is provided with : - a power failure alarm - an earth failure alarm - a lamp test - separate indication for door closed, door locked, door not closed and door not locked 2) Limit switches electrically closed when the door is closed (when more limit switches are provided they may be connected in series). 3) Limitswitcheselectricallyclosedwhensecuringarrangementsareinplace(whenmorelimitswitchesare provided they may be connected in series). 4) Two electrical circuits (also in one multicore cable), onefor the indication of door closed/not closed and the other for door locked /not locked. 5) In case of dislocation of limit switches, indication to show: not closed/not locked/securing arrangement not in place - as appropriate. 7.2.3Theindication panelon the navigation bridge is to be equipped with a selectorswitch "harbour/seavoyage",soarranged that alarm is given if vessel leaves harbour with the bow door or inner door not closed and with any of the securing devices not in the correct position. 7.2.4Awaterleakagedetectionsystemwithaudiblealarmandtelevisionsurveillancearetobearrangedtoprovideanindication to the navigation bridge and to the engine control room of leakage through the inner door. 7.2.5For the space between the bow door and the inner door a television surveillance system is to be fitted with a monitor onthenavigationbridgeandintheenginecontrolroom.Thesystemshallmonitorthepositionofdoorsandasufficientnumber oftheirsecuringdevices.Specialconsiderationistobegiven for lighting and contrasting colour of objects under surveillance. 7.2.6A drainage system is to be arranged in the area between bow door and ramp, as well as in the area between the ramp and inner door where fitted. The system is to be equipped with an acustic alarm function to the navigation bridge for water level in these areas exceeding 0,5 m above the car deck level. 7.2.7For indication and monitoring systems see also Rules for Electrical Installations, Volume IV, Section 16, E. BKI - Rules for Hull - 2014
- 126. H, J Section 6 - Shell Plating6-16/20 8. Operating and maintenance manual 8.1 AnOperatingandMaintenanceManualforthebowdoorandinnerdooristobeprovidedonboardandistocontain necessary information on : - main particulars and design drawings, special safety precautions, details of vessel, equipment and design loading (forramps),keyplanofequipment(doorsandramps),manufacturer'srecommendedtestingforequipment,description of equipment for : - bow doors - inner bow doors - bow ramp/doors - side doors - stern doors - central power pack - bridge panel - engine control room panel - service conditions - limiting heel and trim of ship for loading/unloading - limiting heel and trim for door operations - doors/ramps operating instructions - doors/ramps emergency operating instructions - maintenance - schedule and extent of maintenance - trouble shooting and acceptable clearances - manufacturer's maintenance procedures - register of inspections, including inspection of locking, securing and supporting devices, repairs and renewals. ThisManualistobesubmittedforapprovalthattheabovementioneditemsarecontainedintheOMMandthatthemaintenance part includes the necessary information with regard to inspections, troubleshooting and acceptance/rejection criteria. Note: It is recommended that recorded inspections of the door supporting and securing devices be carried out by the ship's staff at monthly intervals and/or following incidents that could result in damage, including heavy weather and/or contact in the region of the shell doors. Any damages recorded during such inspections are to be reported to BKI. 8.2 Documented operating procedures for closing and securing the bow door and inner doors are to be kept on board and posted at an appropriate place. J. Side Shell Doors and Stern Doors 1. General 1.1 These requirements apply to side shell doors abaft the collision bulkhead and to stern doors leading into enclosed spaces. 1.2 For the definition of securing, supporting and locking devices see H.1.3. 2. Arrangement 2.1 Stern doors for passenger vessels are to be situated above the freeboard deck. Stern doors for Ro-Ro cargo ships and side shell doors may be either below or above the freeboard deck. BKI - Rules for Hull - 2014
- 127. Section 6 - Shell Plating J 6-17/20 2.2 Side shell doors and stern doors are to be so fitted as to ensure tightness and structural integrity commensurate with their location and the surrounding structure. 2.3 Wherethesillofanysideshelldooris belowtheuppermostloadline,thearrangementistobespecially considered. In case of ice strengthening see Section 15. 2.4 Doors should preferably open outwards. 3. Strength criteria The requirements of H.2. apply. 4. Design loads 4.1 The design forces considered for the scantlings of primary members, securing and supporting devices of side shell doors and stern doors are to be not less than the greater of the following values: 4.1.1 Design forces for securing or supporting devices of doors opening inwards: external force: Fe = [kN] internal force: Fi = [kN] 4.1.2 Design forces for securing or supporting devices of doors opening outwards: external force: Fe = [kN] internal force: Fi = [kN] 4.1.3Design forces for primary members: external force: Fe = [kN] internal force: Fi = [kN] A = area of the door opening [m2 ] W = mass of the door [t] Fp = total packing force[kN], where the packing line pressure is normally not to be taken less than 5 N/mm Fo = the greater of Fc or 5 @ A [kN] Fc = accidentalforce[kN]due toloose ofcargoetc., tobeuniformlydistributed overthe area Aandnotto be taken less than 300 kN. For small doors such as bunker doors and pilot doors, the value of Fc may be appropriately reduced. However, the value of Fc may be taken as zero, provided an additional structure such as an inner ramp is fitted, which is capable of protecting the door from accidental forces due to loose cargoes pe = external design pressure determined at the centre of gravity of the door opening and not taken less than: = ps acc. to Section 4, B.2.1 or: pe = [kN/m2 ] for zG < T = 25 [kN/m2 ] for zG > T zG = height of centre of area of door above base line [m]. 4.2 For stern doors of ships fitted with bow doors, pe is not to be taken less than: pe = [kN/m2 ] cRW = service range coefficient as defined in Section 4, A.2.2. cH = see H.3.1.1. 5. Scantlings 5.1 General The requirements of H.4.1 apply analogously with the following additions : BKI - Rules for Hull - 2014
- 128. J Section 6 - Shell Plating6-18/20 ! The strength of side shell doors and stern doors is to be commensurate with that of the surrounding structure. ! Side shell doors and stern doors are to be adequately stiffened and means are to be provided to prevent any lateral or vertical movement of the doors when closed. Adequate strength is to be provided in the connections of the lifting/manoeuvring arms and hinges to the door structure and to the ship's structure. ! where doors also serve as vehicle ramps, the design of the hinges shall take into account the ship's angle of trim and heel which may result in uneven loading on the hinges. ! shelldooropeningsaretohavewell-roundedcornersand adequatecompensationistobearrangedwithwebframes at sides and stringers or equivalent above and below. 5.2 Plating and secondary stiffeners The requirements of H.4.2.1 and H.4.2.2 apply analogously with the following additions: Where doors serve as vehicle ramps, plate thickness and stiffener scantlings are to comply with the requirements of Section 7, B.2. The section modulus of horizontal or vertical stiffeners is not to be less than that required for side framing. Consideration is to be given, where necessary, to differences in fixity between ship's frames and door stiffeners. Where doors serve as vehicle ramps, the stiffener scantlings are not to be less than required for vehicle decks. 5.3 Primary structure The requirements of H.4.3 apply analogously taking into account the design loads specified in 4. 6. Securing and supporting of side shell and stern doors 6.1 General The requirements of H.6.1.1 and H.6.1.2 apply analogously. 6.2 Scantlings The requirements of H.6.2.1, H.6.2.5, H.6.2.6 and H.6.2.9 apply analogously taking into account the design loads specified in 4. 7. Arrangement of securing and locking devices 7.1 Systems for operation 7.1.1 The requirements of H.7.1.1 apply. 7.1.2 Doors which are located partly or totally below the freeboard deck with a clear opening area greater than 6 m² are to be provided with an arrangement for remote control, from a position above the freeboard deck according to H.7.1.2. 7.1.3 The requirements of H.7.1.3 apply. 7.2 Systems for indication/monitoring 7.2.1 The requirements of H.7.2.1, H.7.2.2 and H.7.2.3 apply analogously to doors leading directly to special category spaces or Ro-Ro spaces, as defined in SOLAS 1974, Chapter II-2, Reg. 3, through which such spaces may be flooded. 7.2.2 For Ro-Ro passenger ships, a water leakage detection system with audible alarm and television surveillance is to be arranged to provide an indication to the navigation bridge and to the engine control room of any leakage through the doors. For Ro-Ro cargo ships, a water leakage detection systemwith audible alarmis to be arranged to provide an indication to the navigation bridge. 8. Operating and maintenance manual The requirements of H.8 apply analogously as well as the IACS unified requirement S9. BKI - Rules for Hull - 2014
- 129. Section 6 - Shell Plating K 6-19/20 K. Bulwarks 1. The thickness of bulwark plating is not to be less than : t = [mm] for L#100 m = [mm] for L > 100 m L need not be taken greater than 200 m. The thickness of bulwark plating forward particularly exposed to wash of sea is to be equal to the thickness of the forecastle side plating according to Section 16, B.1. Inwayofsuperstructuresabovethefreeboarddeckabaft0,25L fromF.P.thethickness ofthebulwarkplatingmaybereduced by 0,5 mm. 2. The bulwarkheightorheight of guard rail is not to be less than 1,0 m, the lesser height may be approved ifadequate protection is provided. 3. Plate bulwarks are to be stiffened at the upper edge by a bulwark rail section. 4. The bulwark is to be supported by bulwark stays fitted at every alternate frame. Where the stays are designed as per Fig. 6.5, the section modulus of their cross section effectively attached to the deck is not to be less than: W = 4 @ p q e q R2 [cm3 ] p = ps or pe as the case may be pmin = 15 kN/m2 e = spacing of stays [m] R = length of stay [m] The dimension for calculation of W are to be taken vertical of the plating starting from the base of the stays. In addition Section 3, E.2.3. must be considered. The stays are to be fitted above deck beams, beam knees or carlings. It is recommended to provide flat bars in the lower part which are to be effectively connected to the deck plating. Particularly in ships the strength deck of which is made of higher tensile steel, smooth transitions are to be provided at the end connection of the flat bar faces to deck. 5. On ships carrying deck cargo, the bulwark stays are to be effectively connected to the bulwark and the deck. The stays are to be designed for a load at an angle of heel of 30E. Under such loads the following stresses are not to be exceeded: bending stress: Fb = [N/mm2 ] shear stress: J = [N/mm2 ] For loads caused by containers and by stow and lashing arrangements. See also Section 21, G. 6. Anadequatenumberofexpansionjointsistobeprovidedinthebulwark.Inlongitudinaldirectionthestaysadjacent to the expansion joints shall be as flexible as practicable. The number of expansion joints for ships exceeding 60 m in length should not be less than: n = , but need not be greater than n = 5. 7. Openings in the bulwarks shall have sufficient distance from the end bulkheads of superstructures. For avoiding cracks the connection of bulwarks to deckhouse supports is to be carefully designed. 8. For the connection of bulwarks with the sheer strake C.3.4 is to be observed. 9. Bulwarks are to be provided with freeing ports of sufficient size. See also Section 21, D. 2 and ICLL. BKI - Rules for Hull - 2014
- 130. K Section 6 - Shell Plating6-20/20 Fig. 6.5 Bulwark stay BKI - Rules for Hull - 2014
- 131. Section 7 - Decks A 7-1/9 Section 7 Decks A. Strength Deck 1. General, Definition 1.1 The strength deck is: .1 the uppermost continuous deck which is forming the upper flange of the hull structure, .2 a superstructure deck which extends into 0,4 L amidships and the length of which exceeds 0,15L, .3 a quarter deck or the deck of a sunk superstructure which extends into 0,4 L amidships. At the option of the designer the deck below superstructure deck may be taken as strength deck. 1.2 In way of a superstructure deck which is to be considered as a strength deck, the deck below the superstructure deck istohave thesamescantlingsasa2nd deck,andthedeckbelowthisdeckthesamescantlingsasa3rd deck.Thethicknesses ofastrengthdeckplatingare tobeextended into the superstructure for a distance equal to the width of the deckplatingabreast the hatchway. For strengthening of the stringer plate in the breaks, see Section 16, A.3. 1.3 If the strength deck is protected by sheathing a smaller corrosion addition tK than required by Section 3, K may be permitted. Where a sheathing other than wood is used, attention is to be paid that the sheathing does not affect the steel. The sheathing is to be effectively fitted to the deck. 1.4 For ships with a speed v0 > 1,6 [kn], additional strengthening of the strength deck and the sheerstrake may be required. 1.5 The following definitions apply throughout this Section: k = material factor according to Section 2, B.2. pD = load according to Section 4, B.1. pL = load according to Section 4, C.1. tK = corrosion addition according to Section 3, K. 2. Connection between strength deck and sheerstrake 2.1 The welded connection between strength deck and sheerstrake may be effected by fillet welds according to Table 19.3. Where the plate thickness exceeds approximately 25 mm, a double bevel weld connection according to Section 19, B.3.2, shall be provided for instead of fillet welds. Bevelling of the deck stringer to 0,65 times of its thickness in way of the welded connection is admissible. In special cases a double bevel weld connection may also be required, where the plate thickness is less than 25 mm. 2.2 Where the connection of deck stringer to sheerstrake is rounded, the requirements of Section 6, C.3.3 are to be observed. 3. Openings in the strength deck 3.1 All openings in the strength deck are to have well rounded corners circular openings are to be edge-reinforced. The sectional area of the face bar is not to be less than: Af = 0,25 @ d @ t [cm2 ] d = diameter of openings[cm] t = deck thickness [cm]. Thereinforcingfacebarmaybedispensedwith,wherethediameterislessthan300mmandthesmallestdistancefromanother opening is not less than 5 x diameter of the smaller opening. The distance between the outer edge of openings for pipes etc. BKI - Rules for Hull - 2014
- 132. A Section 7 - Decks7-2/9 and the ship's side is not to be less than the opening diameter. 3.2 The hatchway corners are to be surrounded by strengthened plates which are to extend over at least one frame spacing fore-and-aft and athwartships. Within 0,5 L amidships, the thickness of the strengthened plate is to be equal to thedeckthicknessabreastthehatchwayplusthedeckthicknessbetweenthehatchways.Outside0,5Lamidshipsthethickness of the strengthened plated need not exceed 1,6 times the thickness of the deck plating abreast the hatchway. The reinforcement may be dispensed with in case of proof by a fatigue analysis. 3.3 The hatchway corner radius is not to be less than: r = n @ b (1 – b/B) rmin = 0,1 m n = nmin = 0,1 nmax = 0,25 R = length of hatchway [m] b = breadth [m], of hatchway or total breadth of hatchways in case of more than one hatchway. b/B need not be taken smaller than 0,4. For ships with large hatch openings see 3.6. 3.4 Wherethehatchwaycornersareellipticorparabolic,strengtheningaccordingto3.2isnotrequired.Thedimensions of the elliptical and parabolical corners shall be as shown in Fig. 7.1: Fig. 7.1 Elliptic or parabolic hatch corner Where smaller values are taken for a and c, reinforced insert plates are required which will be considered in each individual case. 3.5 At the corners of the engine room casings, strengthenings according to 3.2 may also be required, depending on the position and the dimensions of the casing. 3.6 For ships with large deck openings according to Section 5, F. the design of the hatch corners will be specially considered on the basis of the stresses due to longitudinal hull girder bending, torsion and transverse loads. Approximately the following formulae can be used to determine the radii of the hatchway corners: r $ c1 A c 2 rmin = 0,15 m for hatchway corners in the strength deck = 0,1 in all other locations c1 = for hatchway corners at deck girders alongside the hatchway, adjacent to a closed deck area BKI - Rules for Hull - 2014
- 133. Section 7 - Decks A 7-3/9 = 0,4 A bQ for hatchway corners at cross deck strips between hatchways adjacent to a closed deck area = for hatchway corners adjacent to a cross deck strip fD = coefficient for deck configuration = 0,25 + for hatchway corners of the strength deck and for decks and coamings above the strength deck = 0,2 + forthestrengthdeck,decksandcoamingsabovethestrengthdeckandfordeckswithinthedistanceofmaximum bL below the strength deck, if a further deck with the same hatchway corner radius is arranged in a distance of less than bL below the strength deck. = 0,1 for lower decks where the distance from the strength deck exceeds bL R = relevant length of large deck openings [m] forward and/or aft of the superstructure Lmin = 100 m Lmax = 300 m bL = breadth of deck girder alongside the hatchway [m] bQ = breadth of cross deck strip between hatchways [m] ForhatchwaycornersaboveorbelowthestrengthdeckbL andbQ aretobetakenasthebreadthsofthelongitudinalortransverse structural members adjacent to the hatchway corners. c2 = tD = plate thickness of the longitudinal structural member [mm] ti = thickness of the hatchway corner plate [mm] 1 $ $ 0,625 MT = totallongitudinalbendingmoment[kNm],accordingtoSection5,A.5attheforwardoraftedgeof the relevant cross deck strip or the relevant closed deck area Iy = moment of inertia [m4 ] of the section according to Section 5, A.5. in the hatchway corner without inserted strengthened plate cs = according to Section 5, C.1.1 for the strength deck = 1,0 for the lower decks z0 = distance of neutral axis of the hull section from the baseline [m] zD = distance of the relevant hatchway corner from the baseline[m] ki = material factor according to Section 2, B. of the relevant hatchway corner Where required by above calculation or on the basis of direct fatigue assessment hatchway corners are to be surrounded by strengthened plates, i.e. insert plates, which extend minimum distances a and b from hatch edges (see Fig. 7.2), where a = [mm] amin = 350 mm b = [mm] Openings in way of hatchway corners are not to be located within the following minimum distances (see Fig. 7.2) BKI - Rules for Hull - 2014
- 134. A Section 7 - Decks7-4/9 Fig. 7.2 Strengthening of hatchway corners a) Opening outside of insert plate c = distance of opening from butt seam = 2 t + h + 50 [mm] for strength deck = 2 t + h/2 + 50 [mm] for lower decks b) Opening inside of insert plate e = distance of opening from longitudinal bulkhead = 2 r + h/2 [mm] for strength deck = 1,5 r + h/2 [mm] for lower decks h = diameter of opening [mm] On the basis of direct calculations, other minimum distances for specific cases may be accepted. Outside 0,5 L midships the thickness of the strengthened plate shall not exceed 1,6 times the thickness of the deck plating abreast the hatchway. 3.7 Stresses due to lateral loads = [N/mm2 ]σ Q MQ = bending moment around the z-axis due to the action of the external water pressure according to Section 4, B.2 and/or cargo loads [kNm], stressing the girder consisting of deck strip, longitudinal hatch coaming and effective parts of longitudinal bulkhead and side shell plating. W1 = section modulus [m³] of the girder specified above abreast hatchway around the vertical axis. Longitudinal hatch coamings can only be included, if carried sufficiently beyond the hatchway ends. Forcontainershipswithhatchwaylengthsnotexceedingapproximately14mandwithtransverseboxgirdersofapproximately equal rigidity, FQ may be determined by the following formulae: FQ = [N/mm2 ] p0 = see Section 4, A.2.2 In the hatch corners of ships with large deck openings according to Section 5, F., the following equation must be complied BKI - Rules for Hull - 2014
- 135. Section 7 - Decks A 7-5/9 with : Fv = see Section 5, D.1.2. FL = see Section 5, D.1. 4. Scantlings of strength deck of ships up to 65 m in length The scantlings of the strength deck for ships, for which proof of longitudinal strength is not required, i.e. in general for ships withlengthL 65m,thesectionalareaofthestrengthdeckwithin0,4Lamidshipsistobedeterminedsuchthattherequirements for the minimum midship section modulus according to Section 5, C.2. are complied with. The thickness within 0,4 L amidship is not to be less than the minimum thickness according to 6. For the range 0,1 L from ends, the requirement of 7.1 apply. 5. Scantlings of strength deck of ships of more than 65 m in length 5.1 Deck sectional area The deck sectional area abreast the hatchways, if any, is to be so determined that the section modulii of the cross section is in accordance with the requirements of Section 5, C. 5.2 Critical plate thickness, buckling strength 5.2.1The critical plate thickness is to be determined according to Section 6, B.2. analogously. 5.2.2Reductions from the critical plate thickness on account of restricted service are not admissible. 5.2.3In regard to buckling strength the requirements of Section 6, B.2.2 apply analogously. 5.3 Deck stringer If the thickness of the strength deck plating is less than that of the side shell plating, a stringer plate is to be fitted having the width of the sheerstrake and the thickness of the side shell plating. 6. Minimum thickness 6.1 The thickness of deck plating for 0,4 L amidships outside line of hatchways, is not to be less than the greater of the two following values: tmin = (4,5 + 0,05 L) [mm] or tE = according to 7.1, L need not be taken greater than 200 m. 6.2 When the deck is located above a level of T + c0 above basis a smaller thickness than tmin may be accepted if the stress level permits such reduction. c0 see Section 4, A.2.2. 7. End thickness, thickness inside line of hatchways 7.1 The thickness of strength deck plating for 0,1 L from the ends and between hatchways is not to be less than: tE1 = [mm] tE2 = [mm] tEmin = (5,5 + 0,02 L) [mm] L need not be taken greater than 200 m. 7.2 Between the midship thickness and the end thickness, the thicknesses are to be tapered gradually. 7.3 The strength of deck structure between hatch openings has to withstand compressive transversely acting loads. Proof of buckling strength is to be provided according to Section 3, F. BKI - Rules for Hull - 2014
- 136. B Section 7 - Decks7-6/9 B. Lower Decks 1. Thickness of decks for cargo loads 1.1 The plate thickness is not to be less than: t = 1,1 a [mm] tmin = (5,5 + 0,02 L) [mm] for the 2nd deck = 6,0 mm for other lower decks L need not be taken greater than 200 m. 1.2 For the critical deck thickness see A.5.2. 2. Thickness of decks for wheel loading 2.1 The thickness of deck plating for wheel loading is to be determined by the following formulae: t = [mm] P = load [kN] of one wheel or group of wheels on a plate panel a @ b 1) considering the aceleration factor av. = Q = axle load [kN] For fork lift trucks Q is generally to be taken as the total weight of the fork lift truck. n = number of wheels or group of wheels per axle av = see Section 4, C.1.1 = 0 for harbour conditions c = factor according to the following formulae: for the aspect ratio b/a =1: for the range 0 < < 0,3 : c = for the range 0,3 # 1,0 : c = 1,20 - 0,40 for the aspect ratio b/a $ 2,5: for the range 0 < < 0,3 : c = for the range 0,3 # 1,0 : c = 1,20 - 0,517 1) Where no data available P is to be taken as 25 kN BKI - Rules for Hull - 2014
- 137. Section 7 - Decks B, C 7-7/9 for intermediate values of b/a the factor c is to be obtained by direct interpolation. f = print area of wheel or group of wheels F = area of plate panel a @ b according to Fig. 7.3 a = width of smaller side of plate panel (in general beam spacing) b = width of larger side of plate panel F need not be taken greater than 2,5 a2 . In case of narrowly spaced wheels these may be grouped together to one wheel print area. Fig. 7.3 Footprint of wheel 2.2 Where the wheel print area is not known, it may approximately be determined as follows: f = [cm2 ] p = specific wheel pressure according to Table 7.1. 2.3 In deck beams and girders, the stress is not to exceed 165/k [N/mm2 ]. Table 7.1 - Specific wheel pressure Type of vehicle Specific wheel pressure p [bar] Pneumatic tyres Solid rubber tyres private cars 2 - trucks 8 - trailers 8 15 fork lift trucks 6 15 3. Machinery decks and accommodation decks The scantlings of machinery decks and other accommodation decks have to be based on the loads given in Section 4, C.3. The thickness of the plates is not to be less than: t = 1,1 @ a @ [mm] tmin = 5 [mm] C. Helicopter Decks 1. General 1.1 The starting/landing zone is to be dimensioned for the largest helicopter type expected to use the helicopter deck. 1.2 Forscantlingpurposes,otherloads(cargo,snow/ice,etc.)aretobeconsideredsimultaneouslyorseparately,depending BKI - Rules for Hull - 2014
- 138. C Section 7 - Decks7-8/9 on the conditions of operation to be expected. Where these conditions are not known, the data contained in 2. may be used as a basis. 1.3 The following provisions in principle apply to starting/landing zones on special pillar-supported landing decks or on decks of superstructures and deckhouses. Note For the convenience of the users of these Rules reference is made to the "Guide to Helicopter/Ship Operations' published by the International Chamber of Shipping (ICS). 2. Design Load The following load cases (LC) are to be considered: 2.1 LC 1 Helicopter lashed on deck, with the following vertical forces acting simultaneously: .1 Wheel and/or skid force P acting at the points resulting from the lashing position and distribution of the wheels and/or supports according to helicopter construction. P = 0,5 @ G (1 + av) [kN] G = maximum permissible take-off weight [kN] av = see Section 4, C.1.1 P = evenly distributed force over the contact area f = 30 x 30 cm for single wheel or according to data supplied by helicopter manufacturers;fordualwheelsorskids to be determined individually in accordance with given dimensions. e = wheel or skid distance according to helicopter types to be expected .2 Force due to weight of helicopter deck Me as follows : Me (1 + av) [kN] .3 Load p = 2,0 kN/m2 evenly distributed over the entire landing deck. 2.2 LC 2 Helicopter lashed on deck, with the following horizontal and vertical forces acting simultaneously: .1 Forces acting horizontally: H = 0,6 (G + Me) + W [Kn] W = Wind load, taking into account the lashed helicopter; wind velocity vw = 50 m/s. .2 Forces acting vertically: V = G + Me [kN] 2.3 LC 3 Normal landing impact, with the following forces acting simultaneously: .1 Wheel and/or skid load P at two points simultaneously, at an arbitrary (most unfavourable) point of the helicopter deck (landing zone + safety zone) P = 0,75 G [kN] .2 Load p = 0,5 kN/m2 evenly distributed BKI - Rules for Hull - 2014
- 139. Section 7 - Decks C 7-9/9 (for taking into account snow or other environmental loads) .3 Weight of the helicopter deck .4 Wind load in accordance with the wind velocity admitted for helicopter operation (vw), where no data are available, vw = 25 m/s may be used. 3. Scantlings of structural members 3.1 Stresses and forces in the supporting structure are to be evaluated by means of direct calculations. 3.2 Permissible stresses for stiffeners, girders and substructure: Fperm= <S = Safety factors according to Table 7.2. 3.3 The thickness of the plating is to be determined according to B.2. where the coefficient c may be reduced by 5%. 3.4 Proof of sufficient buckling strength is to be carried out in accordance with Section 3, F. for structures subjected to compressive stresses. Table 7.2 - Safety factor <S Structural element <S LC1, LC2 LC 3 Stiffeners (deck beam) 1,25 1,1 main girders (deck girder) 1,45 1,45 load-bearing structure (pillar system) 1,7 2,0 BKI - Rules for Hull - 2014
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- 141. Section 8 - Bottom Structures A 8-1/13 Section 8 Bottom Structures A. Single Bottom 1. Floor plates 1.1 General 1.1.1Floor plates are to be fitted at every frame. For the connection with the frames, see Section 19, B.4.2. 1.1.2Deep floors, particularly in the after peak, are to be provided with buckling stiffeners. 1.1.3The floor plates are to be provided with limbers to permit the water to reach the pump suctions. 1.2 Scantlings 1.2.1Floor plates in the cargo hold area Onshipswithoutdoublebottomoroutside any double bottomthe scantlings of floor plates fitted betweenafterpeakbulkhead and collision bulkhead are to be determined according to the following formulae. The section modulus is not to be less than: W = c @ T @ e @ R2 [cm3 ] e = spacing of plate floor [m] R = unsupported span [m], generally measured on upper edge of floor from side shell to side shell. Rmin = 0,7 B, if the floors are not supported at longitudinal bulkheads c = 7,5 for spaces which may be empty at full draught, e.g. machinery spaces, storerooms, etc. = 4,5 elsewhere. The depth of the floor plates is not to be less than : h = 55 @ B – 45 [mm] hmin = 180 mm. In ships having rise of floor, at 0,1 R from the ends of the length R where possible, the depth of the floor plate webs shall not be less than half the required depth. In ships having a considerable rise of floor, the depth of the floor plate webs at the beginning of the turn of bilge is not to be less than the depth of the frame. The web thickness is not to be less than : t = [mm] The web sectional area is to be determined according to B.6.2.2 analogously. 1.2.2The face plates of the floor plates are to be continuous over the span R. If they are interrupted at the centre keelson, they are to be connected to the centre keelson by means of full penetration welding. 1.2.3 Floor plates in the peaks .1 The thickness of the floor plates in the peaks is not to be less than: t = 0,035 L + 5,0 [mm]. The thickness, however, need not be greater than required by B.6.2.1. .2 The floor plate height in the fore peak above top of keel or stem shoe is not to be less than : BKI - Rules for Hull - 2014
- 142. A, B Section 8 - Bottom Structures8-2/13 h = 0,06 H + 0,7 [m]. For small ship deviation from this requirement may be considered. .3 The floor plates in the after peak are to extend over the stern tube (see also Section 13, C.1.4). .4 Wherepropellerrevolutionsareexceeding300rpm(approx.)thepeakfloorsabovethepropelleraretobe strengthened.. Particularly in case of flat bottoms additional longitudinal stiffeners are to be fitted above or forward of the propeller. 2. Longitudinal girders 2.1 General 2.1.1 All single bottom ships are to have a centre girder. Where the breadth measured on top of floors does not exceed 9 mone additional side girder is to be fitted, and two side girders where the breadth exceeds 9 m. Side girders are not required where the breadth does not exceed 6 m. 2.1.2For the spacing of side girders from each other and from the centre girder in way of bottom strengthening forward see Section 6, E.1. 2.1.3The centre and side girders are to extend as far forward and aft as practicable. They are to be connected to the girders of a non-continuous double bottom or are to be scarphed into the double bottom by two frame spacings. 2.2 Scantlings 2.2.1Centre girder The web thickness tw and the sectional area of the face plate Af within 0,7 L amidships is not to be less than: tw = 0,07 L + 5,5 [mm]. Af = 0,7 L + 12 [cm2 ]. Towards theendsthethicknessofthewebplateaswellasthesectionalarea ofthetopplatemaybereducedby10%.Lightening holes are to be avoided. 2.2.2 Side girder The web thickness tw and the sectional area of the face plate Af within 0,7 L amidships is not to be less than: tw = 0,04 L + 5 [mm]. Af = 0,2 L + 6 [cm2 ]. Towards the ends, the thickness of the web plate and the sectional area of the face plate may be reduced by 10%. B. Double Bottom 1. General 1.1 On passenger ships and cargo ships other than tankers a double bottom shall be fitted extending from the collision bulkhead to the afterpeak bulkhead, as far as this is practicable and compatible with the design and proper working of the ship. For oil tankers see Section 24. 1.2 The arrangement shall comply with Chapter II-1 of SOLAS as amended. See also Section 36, C. 1.3 Where a double bottom is required to be fitted the inner bottom shall be continued out to the ship's sides in such a manner as to protect the bottom to the turn of the bilge. Such protection will be deemed satisfactory if the inner bottom is not lower at any part than a plane parallel with the keel line and which is located not less than a vertical distance h measured from the keel line, as calculated by the formula : h = However, in no case is the value of h to be less than 760 mm, and need not be taken as more than 2000 mm. BKI - Rules for Hull - 2014
- 143. Section 8 - Bottom Structures B 8-3/13 1.4 Small wells for hold drainage may be arranged in the double bottom, their depth, however, shall be as small as practicable. A well extending to the outer bottom, may, however, be permitted at the after end of the shaft tunnel. Other wells may be permitted if their arrangement does not reduce the level of protection equivalent to that afforded by a double bottomcomplying with this Section. In no case shall the vertical distance fromthe bottomof such a well to a plane coinciding with the keel line be less than 500 mm. 1.5 In fore- and after peak a double bottom need not be arranged. 1.6 The centre girder should be watertight at least for 0,5 L amidships, unless the double bottom is subdivided by watertight side girders. On ships which are assigned the load line permissible for timber deck load, the double bottom is to be subdivided watertight by the centre girder or side girders as required by the ICLL 66. 1.7 For the double bottom structures of bulk carriers, see Section 23, B.4. 1.8 For bottom strengthening forward see Section 6,E. 1.9 For the material factor k see Section 2, B.2. For the corrosion addition tK see Section 3, K. 1.10 For buckling strength of the double bottom structures see 8.3. 1.11 Ships touching ground whilst loading and discharging On request of the owner, the bottom structures of a ship which is expected to frequently touch ground whilst loading and discharging will be examined particularly. To fulfil this requirement, where the transverse framing system is adopted, plate floors are to be fitted at every frame and the spacing of the side girders is to be reduced to half the spacing as required according to 3.1. When the longitudinal framing system is adopted, the longitudinal girder system according to 7.5 is to be applied. The thickness of bottom plating is to be increased by 10 %, compared to the plate thickness according to Section 6, B.1. to B.5. 2. Centre girder 2.1 Lightening holes Lightening holes in the centre girder are generally permitted only outside 0,75 L amidships. Their depth is not to exceed half the depth of the centre girder and their lengths are not to exceed half the frame spacing. 2.2 Scantlings 2.2.1 The depth of the centre girder is not to be less than: h = 350 + 45 @ B [mm] hmin = 600 mm Where longitudinal wing bulkheads are fitted, the distance between the bulkheads may be inserted in lieu of B, however, not less than 0,8 B. For double bottoms with wing tanks (e.g. on bulk carriers) instead of the breadth B the fictitious breadth B' according to Fig. 8.1 may be used, but not less than 0,8 . B. B' = (2 B + b) for " $ 35° B' = B for " < 35° Fig. 8.1 - Fictitious breadth B’ BKI - Rules for Hull - 2014
- 144. B Section 8 - Bottom Structures8-4/13 2.2.2 The thickness of the centre girder is not to be less than: – within 0,7 L amidships : tm = [mm] for h # 1200 [mm] tm = [mm] for h > 1200 [mm] – 0,15 L at the ends: te = 0,9 A tm ha = depth of centre girder as built [mm] ha need not be taken less than h to calculate tm tm = shall not be less than t according to 7.5 3. Side girders 3.1 Arrangement At least one side girder shall be fitted in the engine room and in way of 0,25 L aft of F.P. In the other parts of the double bottom, one side girder shall be fitted where the horizontal distance between ship's side and centre girder exceeds 4,5 m. Two side girders shall be fitted where the distance exceeds 8 m, and three side girders where it exceeds 10,5 m. The distance of the side girders from each other and from centre girder and ship's side respectively shall not be greater than: 1,8 m in the engine room within the breadth of engine seatings, 4,5 m where one side girder is fitted in the other parts of double bottom, 4,0 m where two side girders are fitted in the other parts of double bottom, 3,5 m where three side girders are fitted in the other parts of double bottom. 3.2 Scantlings The thickness of the side girders is not to be less than : t = [mm] h = depth of the centre girder [mm] according to 2.2. ha = as built depth of side girders [mm] ha need not be taken less than h to calculate t t = shall not be less than t according to 7.5. For strengthenings under the engine seating, see C.2.3. 4. Inner bottom 4.1 The thickness of the inner bottom plating is not to be less than : t = [mm] p = design pressure [kN/m2 ] p is the greater of the following values: p1 = 10 (T - hDB) p2 = 10 @ h, where the inner bottom forms a tank boundary p3 = pi according to Section 4, C.2. h = distance from top of overflow pipe to inner bottom [m] BKI - Rules for Hull - 2014
- 145. Section 8 - Bottom Structures B 8-5/13 hDB = double bottom height [m]. 4.2 If no ceiling according to Section 21, B.1. is fitted on the inner bottom, the thickness determined in accordance with 4.1 for p1 or p2 is to be increased by 2 mm. This increase is not required for ships with the Notation "CONTAINER SHIP". 4.3 For strengthening in the range of grabs, see Section 23, B.4.3. 4.4 For strengthening of inner bottom in machinery spaces, see C.2.4. 5. Double bottom tanks 5.1 Scantlings Structures forming boundaries of double bottom tanks are to comply with the requirements of Section 12. 5.2 Fuel and lubricating oil tanks 5.2.1 In double bottom tanks, oil fuel may be carried, the flash point (closed cup test) of which exceeds 60E C. 5.2.2 Where practicable, lubricating oil discharge tanks or circulating tanks shall be separated from the shell. 5.2.3 For the separation of oil fuel tanks from tanks for other liquids, see Section 12, A.5. 5.2.4 For air, overflow and sounding pipes, see Section 21, E. as well as Rules for Machinery Installations, Volume III, Section 11. 5.2.5 Manholes for access to oil fuel double bottom tanks situated under cargo oil tanks are not permitted in cargo oil tanks nor in the engine room (see also Section 24, A.12.4). 5.2.6 The thickness of structures is not to be less than the minimum thickness according to Section 12, A.7. 5.2.7If the tank top of the lubricating oil circulating tank is not arranged at the same level as the adjacent inner bottom, this discontinuity of the flow of forces has to be compensated by vertical and/or horizontal brackets. The brackets shall be designed with a soft taper at the end of each arm. The thickness of the vertical brackets shall correspond to the thickness of the floor plates according to C.2.2, the thickness of the horizontal brackets shall correspond to the tank top thickness of the circulating tank. The brackets shall be connected to the ship structure by double-bevel welds according to Section 19, B.3.2.2. 5.3 Bilge wells Bilge wells shall have a capacity of more than 0,2 m3 . Small holds may have smaller bilge wells. For the use of manhole covers or hinged covers for the access to the bilge suctions, see Rules for Machinery Installations, Volume III, Section 11. Bilge wells are to be separated from the shell. Section 29, F.5. shall be applied analogously. 5.4 Sea chests 5.4.1 The plate thickness of sea chests is not to be less than : t = [mm] a = spacing of stiffeners [m] p = blow out pressure at the safety valve [bar]. p is not to be less than 2 bar (see also Rules for Machinery Installations, Volume III, Section 11) 5.4.2 The section modulus of sea chest stiffeners is not to be less than: W = 56 @ a @ p @ R2 @ k [cm3 ] a and p see 5.4.1 R = unsupported span of stiffeners[m]. BKI - Rules for Hull - 2014
- 146. B Section 8 - Bottom Structures8-6/13 5.4.3The sea-water inlet openings in the shell are to be protected by gratings. 5.4.4A cathodic corrosion protection with galvanic anodes made of zinc or aluminium is to be provided in sea chests with chest coolers. For the suitably coated plates a current density of 30 :A/m2 is to be provided and for the cooling area a current density of 180 :A/m2 . 6. Double bottom, transverse framing system 6.1 Plate floors 6.1.1 It is recommended to fit plate floors at every frame in the double bottom if transverse framing is adopted. 6.1.2Plate floors are to be fitted at every frame: .1 in way of strengthening of the bottom forward according to Section 6, E., .2 in the engine room, .3 under boiler seatings. 6.1.3 Plate floors are to be fitted: .1 below bulkheads .2 under corrugated bulkheads, see also Section 3, D.4. and Section 23, B.4.3. 6.1.4 For the remaining part of the double bottom, the spacing of plate floors shall not exceed approximately 3 m. 6.2 Scantlings 6.2.1 The thickness of plate floors is not to be less than : tpf = [mm] tm = thickness of centre girder according to 2.2.2. The thickness need not exceed 16,0 mm. 6.2.2The web sectional area of the plate floors is not to be less than : Aw = g @ T @ R @ e (1 – ) k [cm2 ] e = spacing of plate floors [m] R = span between longitudinal bulkheads, if any, [m] = B, if longitudinal bulkheads are not fitted y = distance between supporting point of the plate floor (ship's side, longitudinal bulkhead) and the section considered [m]. The distance y is not to be taken greater than 0,4 R. g = 0,5 for spaces which may be empty at full draught, e.g. machinery spaces, store rooms, etc. = 0,3 elsewhere. 6.2.3Where in small ships side girders are not required (see 3.1) at least one vertical stiffener is to be fitted at every plate floor; its thickness is to be equal to that of the floors and its depth of web at least 1/15 of the height of centre girder. 6.2.4In way of strengthening of bottom forward according to Section 6, E., the plate floors are to be connected to the shell plating and inner bottom by continuous fillet welding. 6.2.5For strengthening of floors in machinery spaces, see C.2.2. 6.3 Watertight floors 6.3.1The thickness of watertight floors is not to be less than that required for tank bulkheads according to Section 12, B.2. In no case their thickness is to be less than required for plate floors according to 6.2. BKI - Rules for Hull - 2014
- 147. Section 8 - Bottom Structures B 8-7/13 6.3.2The scantlings of stiffeners at watertight floors are to be determined according to Section 12, B.3. 6.4 Bracket floors 6.4.1Where plate floors are not required according to 6.1 bracket floors may be fitted. 6.4.2Bracket floors consist of bottom frames at the shell plating and reversed frames at the inner bottom, attached to centre girder, side girders and ship's side by means of brackets. 6.4.3The section modulus of bottom and inner bottom frames is not to be less than: W = n @ c @ a @ R2 @ p @ k [cm3 ] p = design load, as applicable [kN/m2 ] as follows : for bottom frames p = pB according to Section 4, B.3. for inner bottom frames p = pi according to Section 4, C.2. = p1 or p2 according to Section 4, D.1. = 10 (T - hDB) The greater value is to be used. hDB = double bottom height [m] n = 0,44, if p = p2 = 0,55, if p = pi or p1 = 0,70, if p = pB c = 0,60 where struts according to 6.6 are provided at R/2, otherwise c = 1,0 R = unsupported span [m] disregarding struts, if any. 6.5 Brackets 6.5.1The brackets are, in general, to be of same thickness as the plate floors. Their breadth is to be 0,75 of the depth of the centregirderasper2.2.Thebracketsaretobeflangedattheirfreeedges,wheretheunsupportedspanofbottomframesexceeds 1 m or where the depth of floors exceeds 750 mm. 6.5.2At the side girders, bottom frames and inner bottom frames are to be supported by flat bars having the same depth as the inner bottom frames. 6.6 Struts The cross sectional area of the struts is to be determined according to Section 10, C.2. analogously. The design force is to be taken as the following value: P = 0,5 @ p @ a @ R [kN] p = load according to 6.4.3 R = unsupported span according to 6.4.3 7. Double bottom, longitudinal framing system 7.1 General Wherethelongitudinalframingsystemchanges to the transverse framing system, structural continuity or sufficientscarphing is to be provided for. 7.2 Bottom and inner bottom longitudinals 7.2.1The section moduli are to be calculated according to Section 9, B. BKI - Rules for Hull - 2014
- 148. B Section 8 - Bottom Structures8-8/13 7.2.2Where bottomandinnerbottomlongitudinals are coupledby struts in the centre of their unsupported spanR their section modulimaybereducedto60%ofthevaluesrequiredbySection9B.Thescantlingsofthestrutsarebedeterminedinaccordance with 6.6. 7.3 Plate floors 7.3.1The floor spacing shall, in general, not exceed 5 times the mean longitudinal frame spacing. 7.3.2 Floors are to be fitted at every frame as defined in 6.1.3 as well as in the machinery space under the main engine. In the remaining part of the machinery space, floors are to be fitted at every alternate frame. 7.3.3Regarding floors in way of the strengthening of the bottom forward, Section 6, E. is to be observed. For ships intended for carrying heavy cargo, see Section 23. 7.3.4The scantlings of floors are to be determined according to 6.2. 7.3.5The plate floors are to be stiffened at every longitudinal by a vertical stiffener having the same scantlings as the inner bottom longitudinals. The depth of the stiffener need not exceed 150 mm. If necessary a strength check can be required. 7.4 Brackets 7.4.1Where the ship's sides are framed transversely flanged brackets having a thickness of the floors are to be fitted between the plate floors at every transverse frame, extending to the outer longitudinals at the bottom and inner bottom. 7.4.2One bracket is to be fitted at each side of the centre girder between the plate floors where the plate floors are spaced not more than 2,5 m apart. Where the floor spacing is greater, two brackets are should be fitted. 7.5 Longitudinal girder system 7.5.1Wherelongitudinalgirdersare fittedinstead of bottomlongitudinals, the spacing offloorsmaybegreaterthanpermitted by 7.3.1, provided that adequate strength of the structure is proved. 7.5.2The plate thickness of the longitudinal girders is not to be less than: t = (5,0 + 0,03 L) [mm] tmin = 6,0 [mm] 7.5.3The longitudinal girders are to be examined for sufficient safety against buckling according to Section 3,F. 8. Direct calculation of bottom structures 8.1 General, Definitions 8.1.1 Where deemed necessary, a direct calculation of bottomstructures according to Section 23, B.4. may be required. Where it is intended to load the cargo holds unevenly (alternately loaded holds), this direct calculation is to be carried out. Definitions pi = load on inner bottom according to Section 4, C.2. [kN/m²] or Section 4, C.1.3 [kN], (where applicable) Where high density ore cargo is intended to be carried in the holds in a conical shape, in agreement with BKI a corresponding load distribution pi on the inner bottom is to be used for the calculation. = 10 T + p0 @ cF [kN/m²] (hogging condition) = 10 T – p0 @ cF [kN/m²] (sagging condition) p0 , cF see Section 4, A.2.2 FL = designhullgirderbendingstress[N/mm²]accordingtoSection5,D.1.(hoggingorsagging,whichever condition is examined). FR = bending stress [N/mm²] in longitudinal direction, due to the load p, in longitudinal girders BKI - Rules for Hull - 2014
- 149. Section 8 - Bottom Structures B 8-9/13 Fq = bending stress [N/mm²] in transverse direction, due to the load p, in transverse girders J = shear stress in the longitudinal girders or transverse girders due to the load p [N/mm²]. 8.1.2 For two or more holds arranged one behind the other, the calculation is to be carried out for the hogging as well as for the sagging condition. 8.2 Design loads, permissible stresses 8.2.1Design loads p = [kN/m2 ] for loaded holds. = [kN/m2 ] for empty holds. Where the grillage system of the double bottom is subjected to single loads caused by containers, the stresses in the bottom structure are to be calculated for these single loads as well as for the bottom load p’a as per 8.1.1. The permissible stresses specified there in are to be observed. 8.2.2 Permissible stresses .1 Permissible equivalent stress Fv The equivalent stress is not to exceed the following value : Fv = [N/mm2 ] = Fx = stress in the ship’s longitudinal direction = FL + FR = 0 for webs of transverse girders Fy = stress in the ship’s transverse direction = Fq = 0 for webs of longitudinal girders Note Where grillage computer programs are used the following stress definitions apply : Fx = Fy = .2 Permissible max. values for FR, Fq and J The stresses FR, Fq and J alone are not to exceed the following values: FR, Fq = [N/mm2 ] J = [N/mm2 ] 8.3 Buckling strength The buckling strength of the double bottomstructures is to be examined according to Section 3, F. For this purpose the design stresses according to Section 5, D.1. and the stresses due to local loads are to be considered. 9. Testing for tightness Each compartment or tank of a double bottom is to be tested for tightness as specified in Section 12, H. BKI - Rules for Hull - 2014
- 150. C Section 8 - Bottom Structures8-10/13 C. Bottom Structure in Machinery Spaces in Way of the Main Propulsion Plant 1. Single bottom 1.1 The scantlings of floors are to be determined according to A.1.2.1 for the greatest span measured in the engine room. 1.2 The web depth of the plate floors in way of the engine foundation should be as large as possible. The depth of plate floors connected to web frames shall be similar to the depth of the longitudinal foundation girders. In way of the crank case, the depth shall not be less than 0,5 h. The web thickness is not to be less than: t = [mm] h see A.1.2.1. 1.3 The thickness of the longitudinal foundation girders is to be determined according to 3.2.1. 1.4 No centre girder need be fitted in way of longitudinal foundation girders. Intercostal docking profiles are to be fitted instead. The sectional area of the docking profiles is not to be less than: Aw = 10 + 0,2 L [cm2 ]. Docking profiles are not required where a bar keel is fitted. Brackets connecting the plate floors to the bar keel are to be fitted on either side of the floors. 2. Double bottom 2.1 General 2.1.1Lighteningholesinwayoftheenginefoundationaretobekeptassmallaspossiblewithdueregard,however,toaccessibility. Where necessary, the edges of lightening holes are to be strengthened by means of face bars or the plate panels are to be stiffened. 2.1.2Local strengthenings are to be provided beside the following minimum requirements, according to the construction and the local conditions. 2.2 Plate floors Plate floors are to be fitted at every frame. The floor thickness according to B.6.2 is to be increased as follows : minimum 5%, maximum 15%. P = single engine output [kW]. The thickness of the plate floors below web frames is to be increased in addition to the above provisions. In this case the thickness of the plate floors is not to be taken less than the web thickness according to Section 9, A.6.2.1. 2.3 Side girders 2.3.1The thickness of side girders under an engine foundation top plate inserted into the inner bottom is to be similar to the thickness of side girders above the inner bottom according to 3.2.1. 2.3.2Side girders with the thickness of longitudinal girders according to 3.2 are to be fitted under the foundation girders in full height of the double bottom. Where two side girders are fitted on either side of the engine, one may be a half-height girder under the inner bottom for engines up to 3000 kW. 2.3.3Side girders under foundation girders are to be extended into the adjacent spaces and to be connected to the bottom structure. This extension abaft and forward of the engine room bulkheads shall be two to four frame spacings if practicable. 2.3.4No centre girder is required in way of the engine seating (see 1.4). BKI - Rules for Hull - 2014
- 151. Section 8 - Bottom Structures C 8-11/13 2.4 Inner bottom Between the foundation girders, the thickness of the inner bottom plating required according to B.4.1 is to be increased by 2 mm. The strengthened plate is to be extended beyond the engine seating by three to five frame spacings. 3. Engine seating 3.1 General 3.1.1The following rules apply to low speed engines. Seating for medium and high speed engines as well as for turbines will be specially considered. 3.1.2The rigidity of the engine seating and the surrounding bottom structure must be adequate to keep the deformations of the systemdue to the loads within the permissible limits. In special cases, proofof deformations and stresses may be required. Note : 1. At the draught resulting in the maximum deflection in way of the foundation the deflection of two stroke, cross head engines including foundation ought to be less than 1 mm over the length of the engine. In addition to the deflection of engine and foundation the crank web deflections by which the admissible engine deflection may be limited to values less than 1 mm have to be considered as well. For medium speed and high speed engines not only the deflections of crank webs have to be taken into account but for assuring trouble free bearing conditions of the crank shaft the bending deflection of the engine is to be limited. 2. If in special cases a direct calculation of motorseatings may become necessary, the following is to be observed: – For seatings of slow speed two-stroke diesel engines and elastically mounted medium speed four-stroke diesel engines the total deformation ªf = fu + fo shall not be greater than: Îf = 0,2 A RM [mm] RM = length of motor [m] fu = maximum vertical deformation of the seating downwards within the length RM [mm] fo = maximum vertical deformation of the seating upwards within the length RM [mm]. The individual deformations fu and fo shall not be greater than:. fu max , fo max = 0,7 × Îf [mm] Forthecalculationofthedeformationsthemaximumstaticandwaveinduceddynamicinternalandexternaldifferential loads due to local loads and the longitudinal hull girder bending moments as well as the rigidity of the motor are to be considered. – For seatings of non-elastically mounted medium speed four-stroke diesel engines the deformation values shall not exceed 50% of the above values. 3.1.3Dueregardistobepaid,attheinitialdesignstage,toagoodtransmissionofforcesintransverseandlongitudinaldirection, see also B.5.2.7. 3.1.4Thefoundationboltsforfasteningtheengineattheseatingshallbespacednomore than 3 x d apart fromthe longitudinal foundation girder. Where the distance of the foundation bolts from the longitudinal foundation girder is greater, proof of equivalence is to be provided. d = diameter of the foundation bolts. 3.1.5In the whole speed range of main propulsion installations forcontinuousserviceresonancevibrationswithinadmissible vibrationamplitudesmustnotoccur;ifnecessarystructuralvariationshavetobeprovidedforavoidingresonancefrequencies. Otherwise, a barred speed range has to be fixed. Within a range of -10% to + 5% related to the rated speed no barred speed range is permitted. BKI may require a vibration analysis and, if deemed necessary, vibration measurement. 3.2 Longitudinal girders 3.2.1The thickness of the longitudinal girders above the inner bottom is not to be less than: BKI - Rules for Hull - 2014
- 152. C, D Section 8 - Bottom Structures8-12/13 t = [mm] for P < 1500 kW t = [mm] for 1500 P < 7500 kW t = [mm] for P 7500 kW P see 2.2. 3.2.2Where two longitudinal girders are fitted on either side of the engine, their thickness required according to 3.2.1 may be reduced by 4 mm. 3.2.3The sizes of the top plate (width and thickness) shall be sufficient to attain efficient attachment and seating of the engine and -depending on seating height and type of engine- adequate transverse rigidity. The thickness of the top plate shall approximately be equal to the diameter of the fitted-in bolts. The cross sectional area of the top plate is not to be less than: AT = [cm2 ] for P 750 kW = [cm2 ] for P > 750 kW Where twin engines are fitted, a continuous top plate is to be arranged in general if the engines are coupled to one propeller shaft. 3.2.4Thelongitudinalgirdersoftheengineseatingaretobesupportedtransverselybymeansofwebframesorwingbulkheads. The scantlings of web frames are to be determined according to Section 9, A.6. 3.2.5Top plates are preferably to be connected to longitudinal and transverse girders thicker than approx. 15 mm by means of a double bevel butt joint (K butt joint), (see also Section 19, B.3.2). D. Docking Calculation For ships exceeding 120 m in length, for ships of special design, particularly in the aft body and for ships with a docking load of more than 700 kN/m a special calculation of the docking forces is required. The maximum permissible cargo load toremainonboardduringdockingandtheloaddistributionaretobespecified.Theproofofsufficientstrengthcanbeperformed either by a simplified docking calculation or by a direct docking calculation. The number and arrangement of the keel blocks shall agree with the submitted docking plan. Direct calculations are required for ships with unusual overhangs at the ends or with inhomogeneous distribution of cargo. 1. Simplified docking calculation The local forces of the keel blocks acting on the bottomstructures can be calculated in a simplified manner using the nominal keel block load q0. Based on these forces sufficient strength must be shown for all structural bottom elements which may be influenced by the keel block forces. The nominal keel block load q0 is calculated as follows, see also Figure 8.2: q0 = [kN/m] BKI - Rules for Hull - 2014
- 153. Section 8 - Bottom Structures D 8-13/13 Fig. 8.2 - Load on keel block where GS = total ship weight during docking including cargo, ballast and consumables [kN] LKB = length of the keel block range [m]; i.e. in general the length of the horizontal flat keel C = weighting factor = 1,25 in general = 2,0 in the following areas: – within 0,075 @ LKB from both ends of the length LKB – below the main engine – in way of the transverse bulkheads along a distance of 2 @ e – in way of gas tank supports of gas tankers e = distance of plate floors adjacent to the transverse bulkheads [m]; for e no value larger than 1 m needs to be taken. If a longitudinal framing system is used in the double bottom in combination with a centre line girder in accordance with B.2., it may be assumed that the centre line girder carries 50 % of the force and the two adjacent (see Section 6, B.5.2) keel block longitudinals 25 % each. 2. Direct docking calculation If the docking block forces are determined by direct calculation, e.g. by a finite element calculation, considering the stiffness of the ship's body and the weight distribution, the ship has tobe assumed as elastically bedded at the keel blocks. The stiffness of the keel blocks has to be determined including the wood layers. If a floating dock is used, the stiffness of the floating dock is to be taken into consideration. Transitory docking conditions need also to be considered. 3. Permissible stresses The permissible equivalent stress Fv is: Fv = [N/mm2 ] 4. Buckling strength The bottomstructures are to be examined according to Section 3,F. For this purpose a safety factor S = 1,05 has to be applied. BKI - Rules for Hull - 2014
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- 155. Section 9 - Framing System A 9-1/12 Section 9 Framing System A. Transverse Framing 1. General 1.1 Frame spacing Forward of the collision bulkhead and aft of the after peak bulkhead, the frame spacing shall in general not exceed 600 mm. 1.2 Definitions k = material factor according to Section 2, B.2. R = unsupported span [m] according to Section 3, C., see also Fig. 9.1 Rmin = 2,0 m RKu, RKo = length of lower/upper bracket connection of main frames within the length R [m], see Fig. 9.1 Fig. 9.1 - Unsupported span of transverse frames ma = e = spacing of web frames [m] p = ps or pe as the case may be ps = load on ship's sides [kN/m2 ] according to Section 4, B.2.1 pe = load on bow structures [kN/m2 ] according to Section 4, B.2.2 or stern structures according to Section 4, B.2.3 as the case may be pL = 'tween deck load [kN/m2 ] according to Section.4, C.1. p1, p2 = pressure [kN/m2 ] according to Section 4, D.1. Hu = depth up to the lowest deck [m] cr = factor for curved frames BKI - Rules for Hull - 2014
- 156. A Section 9 - Framing System9-2/12 = crmin = 0,75 s = max. height of curve. 2. Main frames 2.1 Scantlings 2.1.1The section modulus WR and shear area AR of the main frames including end attachments are not to be less than: WR = [cm3 ] upper end shear area : ARO = [cm2] lower end shear area : ARU = [cm2] n = 0,9 ! 0,0035 @ L for L < 100 m = 0,55 for L 100 m c = cmin = 0,6 Within the lower bracket connection the section modulus is not to be less than the value obtained for c = 1,0. 2.1.2In ships with more than 3 decks the main frames are to extend at least to the deck above the lowest deck. 2.1.3The scantlings of the main frames are not to be less than those of the 'tween deck frames above. 2.1.4Where the scantlings of the main frames are determined by strength calculations, the following permissible stresses are to be observed: bending stress: Fb = [N/mm2 ] shear stress: J = [N/mm2 ] equivalent stress: Fv = [N/mm2 ] 2.1.5Forces due to lashing arrangements acting on frames are tobe considered when determining the scantlings of the frames (see also Section 21, H) 2.1.6For main frames in holds of bulk carriers see also Section 23, B.5.2. 2.2 Frames in tanks The section modulus W and shear area A of frames in tanks or in hold spaces for ballast water are not to be less than the greater of the following values : W1 = n @ c @ a @ R2 @ p1 @ cr @ k [cm3 ] W2 according to Section 12, B.3.1, and A1 = (1 - 0,817 @ ma) 0,05 @ a @ R @ p1 @ k [cm2 ] A2 = (1 - 0,817 @ ma) 0,04 @ a @ R @ p2 @ k [cm2 ] n and c see 2.1.1. BKI - Rules for Hull - 2014
- 157. Section 9 - Framing System A 9-3/12 2.3 End attachment 2.3.1The lower bracket attachment to the bottom structure is to be determined according to Section 3, D.2. on the basis of the main frame section modulus. 2.3.2The upper bracket attachment to the deck structure and/or to the 'tween deck frames is to be determined according to Section 3, D .2. on the basis of the section modulus of the deck beams or 'tween deck frames whichever is the greater. 2.3.3Where frames are supported by a longitudinally framed deck, the frames fitted between web frames are to be connected to the adjacent longitudinals by brackets. The scantlings of the brackets are to be determined in accordance with Section 3, D.2. on the basis of the section modulus of the frames. 3. 'Tween deck and superstructure frames 3.1 General In ships having a speed exceeding v0 = 1,6 [kn], the forecastle frames forward of 0,1 L from F.P are to have at least the same scantlings as the frames located between the first and the second deck. Where further superstructures, or big deckhouses are arrangedonthe superstructures strengthening of the frames of the space below may be required. For 'tween deck frames in tanks, the requirements for the section moduli W1 and W2 according to 2.2 are to be observed. 3.2 Scantlings The section modulus Wt and shear area At of the ’tween deck and superstructure frames are not to be less than: Wt = 0,55 @ a @ R2 @ p @ cr @ k [cm3 ] At = (1 - 0,817 @ ma) 0,05 @ a @ R @ p @ k [cm2 ] p is not to be taken less than: pmin = 0,4 @ pL @ [kN/m2 ] b = unsupported span of the deck beam below the respective 'tween deck frame [m]. For 'tween deck frames connected at their lower ends to the deck transverses, pmin, is to be multiplied by the factor : f1 = 0,75 + 0,2 1,0 3.3 End attachment 'Tween deck and superstructure frames are to be connected to the main frames below, or to the deck. The end attachment may be carried out in accordance with Fig. 9.2. For 'tween deck and superstructure frames 2.3.3 is to be observed, where applicable. Fig 9.2 - Typical ends attachments of tween deck and superstructure frames 4. Peak frames and frames in way of the stern 4.1 Peak frames 4.1.1 Section modulus WP and shear area AP of the peak frames are not to be less than: BKI - Rules for Hull - 2014
- 158. A Section 9 - Framing System9-4/12 WP = 0,55 @ a @ R2 @ p @ cr @ k [cm3 ] AP = (1 - 0,817 @ ma) 0,05 @ a A R @ p @ k [cm2 ] 4.1.2Where the length of the forepeak does not exceed 0,06 L the section modulus required at half forepeak length may be maintained throughout the entire forepeak. 4.1.3The peak frames are to be connected to the stringer plates to ensure sufficient transmission of shear forces. 4.1.4Ships not exceeding 30 m in length are to have peak frames having the same section modulus as the main frames. 4.1.5Where peaks are to be used as tanks, the section modulus of the peak frames is not to be less than required by Section 12, B.3.1 for W2. 4.2 Frames in way of the stern 4.2.1The frames in way of the cruiser stern arranged at changing angles to the transverse direction are to have a spacing not exceeding 600 mm and are to extend up to the deck above peak tank top maintaining the scantlings of the peak frames. 4.2.2An additional stringer may be required in the after ship outside the afterpeak where frames are inclined considerably and not fitted vertically to the shell. 5. Strengthenings in fore- and aft body 5.1 General In the fore body, i.e. from the forward end to 0,15 L behind F.P., flanged brackets have to be used in principle. As far as practicable and possible, tiers of beams or web frames and stringers are to be fitted in the fore- and after peak. 5.2 Tiers of beams 5.2.1Forward of the collision bulkhead, tiers of beams (beams at every other frame) generally spaced not more than 2,6 m apart, measured vertically, are to be arranged below the lowest deck within the forepeak. Stringer plates are to be fitted on the tiers of beams which are to be connected by continuous welding to the shell plating and by a bracket to each frame. The scantlings of the stringer plates are to be determined from the following formulae: width b = 75 [mm] thickness t = 6,0 + [mm]. 5.2.2The cross sectional area of each beam is to be determined according to Section 10, C.2 for a load P = A @ p [kN] A = load area of a beam [m2 ] p = ps or pe, whichever is applicable. 5.2.3In the after peak, tiers of beams with stringer plates generallyspaced 2,6 mapart,measuredvertically, are to be arranged as required under 5.2.1, as far as practicable with regard to the ship's shape. 5.2.4Intermittent welding at the stringers in the afterpeakistobeavoided.Anyscallopingattheshellplatingistoberestricted to holes required for welding and for limbers. 5.2.5Where peaks are used as tanks, stringer plates are to be flanged or face bars are to be fitted at their inner edges. Stringers are to be effectively fitted to the collision bulkhead so that the forces can be properly transmitted. 5.2.6 Whereperforateddecksarefittedinsteadoftiersofbeams,theirscantlingsaretobedeterminedasforwashbulkheads according to Section 12, G. The requirements regarding cross sectional area stipulated in 5.2.2 are, however, to be complied with. 5.3 Web frames and stringers 5.3.1Where web frames and supporting stringers are fitted instead of tiers of beams, their scantlings are to be determined BKI - Rules for Hull - 2014
- 159. Section 9 - Framing System A 9-5/12 as follows: .1 Section modulus: W = 0,55 @ e @ R2 @ ps @ nc @ k [cm3 ] .2 Web sectional area at the supports: Aw = 0,05 @ e @ R1 @ ps @ k [cm2 ] R = unsupported span [m], without consideration of cross ties, if any R1 = similar to R, however, considering cross ties, if any nc = coefficient according to the following Table 9.1. 5.3.2Vertical transverses are to be interconnected by cross ties the cross sectionalareaofwhichistobedeterminedaccording to 5.2.2. 5.3.3 Where web frames and stringers in the fore body are dimensioned by strength calculations the stresses shall not exceed the permissible stresses in 2.1.4. Note Wherealargeandlongbulbousbowisarrangedadynamicpressurepsdyn istobeappliedunilaterally.Theunilateralpressure can be calculated approximately as follows : psdyn = po @ cF @ [kN/m2 ] po , cF , z and f according to Section 4, with f = 0,75. For the effective area of psdyn, the projected area of the z-x-plane from forward to the collision bulkhead may be assumed. Table 9.1 - Reduction coefficient nc Number of cross ties nc 0 1 2 3 1,0 0,5 0,3 0,2 5.4 Web frames and stringers in 'tween decks and superstructure decks Where the speed of the ship exceeds v0 = 1,6 [kn] or in ships with a considerable bow flare respectively, stringers and transverses according to 5.3areto be fitted within0,1Lfromforwardperpendicularin'tweendeckspacesandsuperstructures. The spacing of the stringers and transverses shall be less than 2,8 m. A considerable bow flare exists, if the flare angel exceeds 40°, measured in the ship's transverse direction and related to the vertical plane. 5.5 Tripping brackets 5.5.1Between the point of greatest breadth of the ship at maximum draft and the collision bulkhead tripping brackets spaced notmorethan2,6m,measuredvertically,accordingtoFig.9.3aretobefitted.Thethicknessofthebracketsistobedetermined according to 5.2.1. Where proofofsafetyagainsttrippingisprovidedtrippingbrackets may partly or completely be dispensed with. 5.5.2In the same range. in 'tween deck spaces and superstructures of 3 m and more in height, tripping brackets according to 5.5.1 are to be fitted. BKI - Rules for Hull - 2014
- 160. A Section 9 - Framing System9-6/12 Fig. 9.3 - Tripping brackets 5.5.3Wherepeaksorotherspacesforwardofthecollisionbulkheadareintendedtobeusedastanks.trippingbracketsaccording to 5.5.1 are to be fitted between tiers of beams or stringers. 5.5.4For ice strengthening, see Section 15. 6. Web frames in machinery spaces 6.1 Arrangement 6.1.1Intheengineandboilerroom,webframesaretobefitted. Generally, they should extend up to the uppermost continuous deck. They are to be spaced not more than 5 times the frame spacing in the engine room. 6.1.2For combustion engines, web frames shall generally be fitted at the forward and aft ends of the engine. The web frames are to be evenly distributed along the length of the engine. 6.1.3Where combustion engines are fitted aft, stringers spaced 2,6 m apart are to be fitted in the engine room, in alignment with the stringers in the after peak, if any. Otherwise the main frames are to be adequately strengthened. The scantlings of the stringers shall be similar to those of the web frames. At least one stringer is required where the depth up to the lowest deck is less than 4 m. 6.1.4For the bottom structure in machinery spaces, see Section 8, C. 6.2 Scantlings 6.2.1The section modulus of web frames is not to be less than: W = 0,8 @ e @ R2 @ ps @ k [cm3 ] The moment of inertia of web frames is not to be less than: I = H (4,5 H n 3,5) ci @ 102 [cm4 ] for 3m # H # 10m I = H (7,25 H n 31) ci @ 102 [cm4 ] for H > 10 m ci = 1 + (Hu - 4) 0,07 The scantlings of the webs are to be calculated as follows : depth h = 50 @ H [mm], hmin = 250 mm thickness t = [mm], tmin = 8,0 mm. 6.2.2Ships with a depth of less than 3 m are to have web frames with web scantlings not less than 250 x 8 mm and a minimum face sectional area of 12 cm2 . BKI - Rules for Hull - 2014
- 161. Section 9 - Framing System A, B 9-7/12 6.2.3 In very wide engine rooms it is recommended to provide side longitudinal bulkheads. B. Bottom, Side- and Deck Longitudinals, Side Transverses 1. General 1.1 Longitudinals shall preferably be continuous through floor plates and transverses. Attachments of their webs to the webs of floor plates and transverses are to be such that the support forces will be transmitted without exceeding a shear stress of 100/k [N/mm2 ]. For longitudinal frames and beams sufficient fatigue strength according to Section 20 is to be demonstrated. Ahead of 0,1 L from F.P. webs of longitudinals are to be connected effectively at both ends. If the flare angle is more than 40° additional heel stiffeners or brackets are to be arranged. 1.2 Where longitudinals abut at transverse bulkheads or webs, brackets are to be fitted. These longitudinals are to be attached to the transverse webs or bulkheads by brackets with the thickness of the stiffeners web thickness, and with a length of weld at the longitudinals equal to 2 x depth of the longitudinals. 1.3 Outside the upper and the lower hull flange, the cross sectional areas stipulated in 1.2 may be reduced by 20%. 1.4 Where longitudinals are sniped at watertight floors and bulkheads, they are to be attached to the floors by brackets of the thickness of plate floors, and with a length of weld at the longitudinals equal to 2 x depth of the bottom longitudinals. (For longitudinal framing systems in double bottoms, see Section 8, B.7.) 1.5 For buckling strength of longitudinals see Section.3, F.2.3 and 3. 2. Definitions k = material factor according to Section 2, B.2. R = unsupported span [m], see also Fig.9.4 p = load [kN/m2 ] = pB,pB1 according to section 4.B.3. for bottom longitudinals. = ps, ps1 or pe according to Section 4, B.2.1 for side longitudinals = pl accordingtoSection4,D.1.1.for longitudinals atship's sides, at longitudinal bulkheads and inner bottom in way of tanks. For bottom longitudinals in way of tanks p due to tank pressure need not to be taken larger than [kN/m2 ] For side longitudinals below Tmin p need not to be taken larger than: [kN/m2 ] For the expression in the squared brackets no value < 0 shall be used. = pd according to Section 4, D.2. for longitudinals at ship's sides, at deck and at longitudinal bulkheads in tanks intended to be partially filled. = pD according to Section 4, B.1. for deck longitudinals of the strength deck = pDA according to Section 4, B.5. for exposed decks which are not to be treated as strength deck = pi accordingtoSection4,C.2.forinnerbottomlongitudinals,however,notlessthantheloadcorresponding to the distance between inner bottom and deepest load waterline = pL according to Section 4, C.1. for longitudinals of cargo decks and for inner bottom longitudinals p0 = according to Section 4, A.2.2 cF = according to Section 4, Table 4.1 BKI - Rules for Hull - 2014
- 162. B Section 9 - Framing System9-8/12 Tmin = smallest ballast draught FL = Axial stress in the profile considered [N/mm2 ] according to Section 5, D.1. z = distance of structure [m] above base line. xR = distance [mm] from transverse structure at I and J respectively (see Fig.9.4) m = ; m $ ma = see A.1.2 mK = RKI,RKJ = effective supporting length [mm] due to heel stiffeners and brackets at frame I and J (see Fig. 9.4) RK = c1 = For Rb # 0,3 @ hb, = 0 is to be taken. hs, Rb, hb, he see Fig. 9.4 hs = height of the heel stiffener [mm] Rb, hb = dimensions of the brackets [mm] c2 = 3 in general c2 = 1 for flanged brackets (see Fig. 9.4 (c)) he = height of bracket [mm] in the distance xR = hs + 0,3 A hb of frame I and J respectively If no heel stiffeners or brackets are arranged the respective values are to be taken as (hs, hb, ) = 0 (see Fig. 9.4 (d)). BKI - Rules for Hull - 2014
- 163. Section 9 - Framing System B 9-9/12 Fig. 9.4 - End attachment 3. Scantlings of longitudinals and longitudinal beams 3.1 The section modulus WR and shear area AR of longitudinals and longitudinal beams of the strength deck is not to be less than : WR = @ m @ a @ R2 @ p [cm3 ] AR = (1 - 0,817 @ ma) 0,05 @ a @ R @ p @ k [cm2 ], The permissible stress Fpr is to be determined according to the following formulae : Fpr = Fperm - *FL* [N/mm2 ] Fpr # [N/mm2 ] BKI - Rules for Hull - 2014
- 164. B Section 9 - Framing System9-10/12 Fperm= [N/mm2 ] Fperm max = [N/mm2 ] For side longitudinals WR and AR shall not be less than : WRmin= [cm3 ] ARmin = (1 – 0,817 @ ma) 0,037 @ a @ R @ psl @ k [cm2 ] psl according to Section 4,B.2.1.1 and 2.1.2 respectively. ForfatiguestrengthcalculationsaccordingtoSection20,Table20.1bendingstressesduetolocalstiffenerbendingandlongitudinal normal stresses due to global hull girder bending are to be combined. Bending stresses from local stiffener bending due to lateral loads p can be calculated as follows: for 0 # xR # Rk FA = [N/mm2 ] for xR = hs + Rb FB = FA @ m1 [N/mm2 ] Wa = section modulus of the profile [cm3 ] including effective plate width according to Section 3, F.2.2 Fh = according to Section 3, L.1. m1 = 1 – 4 @ c3 @ [1 – 0,75 @ c3] for position B at I c3I = for position B at J c3J = The stresses at point A shall not be less than the stresses in adjacent fields (aft of frame I and forward of frame J respectively). In way of curved shell plates (e.g. in the bilge area) section modulus WRmin, shear area ARmin, and stress FB can be reduced by the factor CR. CR = t = thickness of shell plating [mm] Ia = moment of inertia of the longitudinal frame [cm4 ], including effective width R = bending radius of the plate [m] 3.2 In tanks, the section modulus is not to be less than W2 according to Section 12, B.3.1.1. 3.3 Where the scantlings of longitudinals are determined by strength calculations, the total stress comprising local bending and normal stresses due to longitudinal hull girder bending is not to exceed the total stress value Fperm and Fperm max respectively as defined in 3.1. 3.4 If non symmentrical section are used additional stresses according to Section 3, L. shall be considered. 3.5 Wherenecessary, forlongitudinals between transversebulkheadsandsidetransversesadditionalstressesresulting from the deformation of the side transverses are to be taken into account. If no special verification of stresses due to web frame deformations is carried out, the following minimum values are to be considered for fatigue strength verification of side longitudinals : BKI - Rules for Hull - 2014
- 165. Section 9 - Framing System B 9-11/12 FDF = ± 0,1 @ [N/mm2 ] hw = web height of profile i [mm] (see Section 3, Fig. 3.3) 'Rb = ( hsI + RbI + hsJ + RbJ ) @ 10-3 [m] (see Fig. 9.4) RR = unsupported web frame length [m] (see Fig. 9.5) DF = height of web frame [m] (see Fig. 9.5) Cp = weighting factor regarding location of the profile: = zRo = z-coordinate of web frame outset above basis [m] (see Fig. 9.5), zRo < T CT = correction regarding location of the profile i to the waterline = 0 # CT # 0,1 Fig. 9.5 - Definitions 3.6 Where struts are fitted between bottom and inner bottom longitudinals, see Section 8, B.7.2. 3.7 For scantlings of side longitudinals in way of those areas which are tobe strengthened against loads due to harbour and tug manoeuvres see Section 6, C.5. 3.8 In the fore body where the flare angle " is more than 40° and in the aft body where the flare angle " is more than 75° the unsupported span of the longitudinals located above Tmin ! co shall not be larger than 2,6 m; co see Section 4, A.2. Otherwise tripping brackets according to A.5.5 are to be arranged. co see Section 4, A.2. 3.9 The sideshelllongitudinalswithin the range from0,5 below the minimumdraught up to 2,0 mabove the maximum draught and a waterline breadth exceeding 0,9 @ B are to be examined for sufficient strength against berthing impacts. The force induced by a fender into the side shell may be determined by : 0 < D # 2 100 [t]: Pf = 0,08 · D [kN] 2 100 < D # 17 000 [t]: Pf = 170 [kN] D > 17 000 [t]: Pf = D/100 [kN] D = displacement of the ship [t] Dmax= 100 000 t 3.10 In order to withstand the load Pf the section modulus W R of side shell longitudinals are not to be less than : [cm3 ] k = Material factor Mf = bending moment BKI - Rules for Hull - 2014
- 166. B Section 9 - Framing System9-12/12 = [kNm] R = unsupported length [m] 4. Side transverses 4.1 The section modulus W and shear area AW of side transverses supporting side longitudinals is not to be less than: W = 0,55 @ e @ R2 @ p @ k [cm3 ] Aw = 0,05 @ e @ R @ p @ k [cm2 ] 4.2 Where the side transverses are designed on the basis of strength calculations the following stresses are not to be exceeded: Fb = [N/mm2 ] J = [N/mm2 ] Fv = [N/mm2 ] Side transverses and their supports (e. g. decks) are to be checked according to Section 3, F. with regard to their buckling strength. Note : The web thickness can be dimensioned depending on the size of the unstiffened web field as follows : t = a, b = length of side of the unstiffened web plate field, a b f = 0,75 in general = 0,9 in the aft body with extreme flare and in the fore body with flare angles " are less or equal 40° = 1,0 in the fore body where flare angles " are greater than 40° In the fore body where flare angles " are larger than 40° the web in way of the deck beam has to be stiffened. 4.3 In tanks the web thickness shall not be less than the minimum thickness according to Section 12, A.7., and the section modulus and the cross sectional area are not to be less than W2 and Aw2 according to Section.12, B.3. 4.4 Thewebsofsidetransverseswithintherangefrom0,5mbelowtheminimumdraughtupto2,0mabovethemaximum draught and a waterline breadthexceeding0,9ABaretobeexaminedforsufficientbucklingstrengthagainstberthingimpacts. The force induced by a fender into the web frame may be determined as in 3.9. 4.5 In order to withstand the load Pf on the web frames, the following condition has to be met: Pf < Pfu Pf = see 3.9 Pfu = [kN] C = 0,17 in general C = 0,05 for web frame cutouts with free edges in way of continuous longitudinal ts = web thickness of the side transverses [mm]. ReH = minimum nominal upper yield strength [N/mm2 ] of the steel used for the webs of side transverses. 5. Strengthenings in the fore and aft body In the fore and aft peak web frames and stringers or tiers of beams respectively are to be arranged according to A.5. BKI - Rules for Hull - 2014
- 167. Section 10 - Deck Beams and Supporting Deck Structures A 10-1/5 Section 10 Deck Beams and Supporting Deck Structures A. General 1. Definitions k = material factor according to Section 2, B.2. R = unsupported span [m] according to Section 3, C. e = width of deck supported, measured from centre to centre of the adjacent unsupported fields [m] p = deck load pD, pDA or pL [kN/m2 ], according to Section 4, B. and C. c = 0,55 = 0,75 for beams, girders and transverses which are simply supported on one or both ends. Ps = pillar load = P @ A + Pi [kN] A = load area for one pillar [m2 ] Pi = load from pillars located above the pillar considered [kN] 8s = degree of slenderness of the pillar = $ 0,2 Rs = length of the pillar [cm] ReH = nominal yield point [N/mm2 ] E = Young’s modulus [N/mm2 ] = 2,06 x 105 is = radius of gyration of the pillar = [cm] = 0,25 ds for solid pillars of circular cross section = 0,25 for tubular pillars Is = moment of inertia of the pillar [cm4 ] As = sectional area of the pillar [cm2 ] ds = pillar diameter [cm] da = outside diameter of pillar [cm] di = inside diameter of pillar [cm]. ma = factor according to Section 9, A.1.2 2. Permissible stresses Where the scantlings of girders not forming part of the longitudinal hull structure, or of transverses, deck beams, etc. are determined by means of strength calculations the following stresses are not to be exceeded: BKI - Rules for Hull - 2014
- 168. A, B Section 10 - Deck Beams and Supporting Deck Structures10-2/5 Fb = [N/mm2 ] J = [N/mm2 ] Fv = [N/mm2 ] 3. Buckling strength The buckling strength of the deck structures is to be examined according to Section 3, F. For this purpose the design stresses according to Section 5, D.1. and the stresses due to local loads are to be considered. B. Deck Beams and Girders 1. Transverse deck beams and deck longitudinals The section modulus Wd and shear area Ad of transverse deck beams and of deck longitudinals between 0,25 H and 0,75 H above base line is to be determined by the following formula: Wd = c @ a @ p . R2 . k [cm3 ] Ad = (1 - 0,817 @ ma) 0,05 @ a @ R @ p @ k [cm2 ] 2. Deck longitudinals in way of the upper and lower hull flange Thesectionmodulusofdecklongitudinalsofdeckslocatedbelow0,25Hand/orabove0,75Hfrombaselineistobecalculated according to Section 9, B. 3. Attachment 3.1 Transverse deck beams are to be connected to the frames by brackets according to Section 3, D.2. 3.2 Deck beams crossing longitudinal walls and girders may be attached to the stiffeners of longitudinal walls and the webs of girders respectively by welding without brackets. 3.3 Deck beams may be attached to hatchway coamings andgirdersbydoublefilletweldswherethereisnoconstraint. The length of weld is not to be less than 0,6 x depth of the section. 3.4 Where deck beams are to be attached to hatchway coamingsand girders of considerable rigidity (e.g. box girders), brackets are to be provided. 3.5 Within 0,6 L amidships, the arm lengths of the beam brackets in single deck ships are to be increased by 20%. The scantlings of the beam brackets need, however, not be taken greater than required for the Rule section modulus of the frames. 3.6 Regarding the connection of deck longitudinals to transverses and bulkheads, Section 9, B.1. is to be observed. 4. Girders and transverses 4.1 The section modulus W and shear area Aw are not to be less than: W = c @ e @ R2 @ p @ k [cm3 ]. Aw = 0,05 @ p @ e @ R @ k [cm2 ]. 4.2 The depth of girders is not to be less than 1/25 of the unsupported span. The web depth of girders scalloped for continuous deck beams is to be at least 1,5 times the depth of the deck beams. Scantlings of girders of tank decks are to be determined according to Section 12, B.3. 4.3 Where a girder does not have the same section modulus throughout all girder fields, the greater scantlings are to BKI - Rules for Hull - 2014
- 169. Section 10 - Deck Beams and Supporting Deck Structures B, C 10-3/5 be maintained above the supports and are to be reduced gradually to the smaller scantlings. 4.4 End attachments of girders at bulkheads are to be so dimensioned that the bending moments and shear forces can be transferred. Bulkhead stiffeners under girders are to be sufficiently dimensioned to support the girders. 4.5 FaceplatesaretobestiffenedbytrippingbracketsaccordingtoSection3,H.2.5.Atgirdersofsymmetricalsection, they are to be arranged alternately on both sides of the web. 4.6 For girders in line of the deckhouse sides under the strength deck, see Section 16, A.3.2. 4.7 For girders forming part of the longitudinal hull structure and for hatchway girders see E. 5. Supporting structure of windlasses and chain stoppers 5.1 Forthesupportingstructureunderwindlassesandchainstoppers,thefollowingpermissiblestressesaretobeobserved: Fb = [N/mm2 ] J = [N/mm2 ] Fv # [N/mm2 ] 5.2 The acting forces are to be calculated for 80% and 45% respectively of the rated breaking load of the chain cable, i.e.: – for chain stoppers 80% – for windlasses 80% , where chain stoppers are not fitted. – for windlasses 45%,where chain stoppers are fitted. SeealsoRulesforMachineryInstallations,VolumeIII,Section14,D.andRulesforMaterials,VolumeV,Section 13,Table.13.7. C. Pillars 1. General 1.1 Structural members at heads and heels of pillars as well as substructures are to be constructed according to the forces they are subjected to. The connection is to be so dimensioned that at least 1 cm2 cross sectional area is available for 10 kN of load. Where pillars are affected by tension loads doublings are not permitted. 1.2 Pillars in tanks are to be checked for tension. Tubular pillars are not permitted in tanks for flammable liquids. 1.3 For structural elements of the pillars' transverse section, sufficient buckling strength according to Section.3, F. hastobeverified.Thewallthicknessoftubularpillars which may be expected to bedamagedduringloadingandunloading operations is not to be less than: tw = 4,5 + 0,015 da [mm] for da # 300 mm tw = 0,03 da [mm] for da > 300 mm da = outside diameter of tubular pillar [mm] 1.4 Pillars also loaded by bending moments have to be specially considered. 2. Scantlings The sectional area of pillars is not to be less than: BKI - Rules for Hull - 2014
- 170. C, D Section 10 - Deck Beams and Supporting Deck Structures10-4/5 As req= [cm2 ] Fp = permissible compressive stress [N/mm2 ] = 6 = reduction factor = k = np = 0,34 for tubular and rectangular pillars = 0,49 for open sections S = safety factor = 2,00 in general = 1,66 in accommodation area D. Cantilevers 1. General 1.1 In order to withstand the bending moment arising from the load P, cantilevers for supporting girders, hatchway coamings, engine casings and unsupported parts of decks are to be connected to transverses, web frames, reinforced main frames, or walls. 1.2 When determining the scantlings of the cantilevers and the aforementioned structural elements, it is to be taken into consideration that the cantilever bending moment depends on the load capacity of the cantilever, the load capacity being dependent on the ratio of rigidity of the cantilever to that of the members supported by it. 1.3 Face plates are to be secured against tilting by tripping brackets fitted to the webs at suitable distances (see also Section 3, H.2.). 1.4 Particulars of calculation, together with drawings of the cantilever construction are to be submitted for approval. 2. Permissible stresses 2.1 When determining the cantilever scantlings, the following permissible stresses are to be observed: .1 Where single cantilevers are fitted at greater distances: bending stress: Fb = [N/mm2 ] shear stress: J = [N/mm2 ] .2 Where several cantilevers are fitted at smaller distances (e.g. at every frame): bending stress: Fb = [N/mm2 ]. shear stress: J = [N/mm2 ] BKI - Rules for Hull - 2014
- 171. Section 10 - Deck Beams and Supporting Deck Structures E 10-5/5 equivalent stress: Fv < = [N/mm2 ]. .3 The stresses in web frames are not to exceed the values specified in .1 and .2 above. E. Hatchway Girders and Girders Forming Part of the Longitudinal Hull Structure 1. Thescantlingsoflongitudinalandtransversehatchwaygirdersaretobedeterminedonthebasisofstrengthcalculations. The calculations are to be based upon the deck loads calculated according to Section 4, B. and.C. 2. The hatchway girders are to be so dimensioned that the stress values given in Table 10.1 will not be exceeded. Table 10.1 - Maximum stress values FR for hatchway girders Longitudinal coaming and girders of the strength deck All other hatchway girders upper and lower flanges : FR = [N/mm2 ] FR = [N/mm2 ] deck level: FR = [N/mm2 ] 3. For continuous longitudinal coamings the combined stress resulting from longitudinal hull girder bending and local bending of the longitudinal coaming is not to exceed the following value : FL + FR # [N/mm2 ] FR = local bending stress in the ship's longitudinal direction FL = design longitudinal hull girder bending stress according to Section 5, D.1. 4. The equivalent stress is not to exceed the following value: Fv,all = [N/mm2 ] for L < 90 m = [N/mm2 ] for L $ 90 m = Fx = FL + FR Fy = stress in the ship's transverse direction J = shear stress Jmax = [N/mm2 ]. The individual stresses FR and Fy are not to exceed 150/k [N/mm2 ]. 5. The requirements regarding buckling strength according to A.3. are to be observed. 6. Weldings at the top of hatch coamings are subject to special approval. BKI - Rules for Hull - 2014
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- 173. Section 11 - Watertight Bulkheads A 11-1/8 Section 11 Watertight Bulkheads A. General 1. Watertight subdivision 1.1 All ships are to have a collision bulkhead, a stern tube bulkhead and one watertight bulkhead at each end of the engine room. In ships with machinery aft, the stern tube bulkhead may substitute the aft engine room bulkhead. 1.2 For ships without longitudinal bulkheads in the cargo hold area the number of watertight transverse bulkheads should, in general, not be less than given in Table 11.1. Table 11.1 - Number of watertight transverse bulkheads L [m] Arrangement of machinery space aft elsewhere L 65 65 < L 85 85 < L 105 105 < L 125 125 < L 145 145 < L 165 165 < L 185 3 4 4 5 6 7 8 4 4 5 6 7 8 9 L > 185 to be special considered 1.3 One or more of the watertight bulkheads required by 1.2, may be dispensed with where the transverse strength of the ship is adequate. The number of watertight bulkheads will be entered into the Register. 1.4 Number and location of transverse bulkheads fitted in addition to those specified in 1.1 are to be so selected as to ensure sufficient transverse strength of the hull. 1.5 For ships which require proof of survival capability in damaged conditions, the watertight sub-division will be determined by damage stability calculations. For oil tankers see Section 24, A.2., for passenger vessels see Section 29-I, C., for special purpose ships see Section 29-II,.C., for cargo ships of more than 100 m in length see Section 36 and for supply vessels see Section 34, A.2. For liquefied gas tankers see Rules for Ships Carrying Liquefied Gases in Bulk, Volume IX, Section 2, for chemical tankers see Rules for Ships Carrying Dangerous Chemicals in Bulk, Volume X, Section 2. 2. Arrangement of watertight bulkheads 2.1 Collision bulkhead 2.1.1A collision bulkhead shall be located at a distance from the forward perpendicular of not less than 0,05 Lc or 10 m, whichever is the less, and, except as may be permitted by the Administration, not more than 0,08 Lc or 0,05 Lc + 3 m, whichever is the greater 2.1.2Where any part of the ship below the waterline extends forward of the forward perpendicular, e.g., a bulbous bow, the distance x shall be measured from a point either: – at the mid-length of such extension, i.e. x = 0,5 @ a – at a distance 0,015 Lc forward of the forward perpendicular, i.e. x = 0,015 @ Lc, or – at a distance 3 m forward of the forward perpendicular, i.e. x = 3,0 m whichever gives the smallest measurement. BKI - Rules for Hull - 2014
- 174. A Section 11 - Watertight Bulkheads11-2/8 The length Lc and the distance a are to be specified in the approval documents. 2.1.3If 2.1.2 is applicable, the required distances specified in 2.1.1 are to be measured from a reference point located at a distance x forward of the F.P. Fig.11.1 - Location of collision bulkhead 2.1.4Thecollisionbulkheadshallextendwatertightuptothebulkheaddeck.Thebulkheadmayhavestepsorrecesses provided they are within the limits prescribed in 2.1.1. 2.1.5No doors, manholes, access openings, or ventilation ducts are permitted in the collision bulkhead below the bulkhead deck. 2.1.6Except as provided in 2.1.7 the collision bulkhead may be pierced below the bulkhead deck by not more than one pipe for dealing with fluid in the forepeak tank, provided that the pipe is fitted with a screwdown valve capable of being operated fromabove the bulkheaddeck,thevalvechestbeingsecuredinsidetheforepeaktothecollisionbulkhead.TheAdministration may, however, authorize the fitting of this valve on the after side of the collision bulkhead provided that the valve is readily accessible under all service conditions and the space in which it is located is not a cargo space. All valves shall be of steel, bronze or other approved ductile material. Valves of ordinary cast iron or similar material are not acceptable. 2.1.7 Iftheforepeak is divided to hold two differentkindsofliquidstheAdministrationmayallowthecollisionbulkhead to be pierced below the bulkhead deck by two pipes, each of which is fitted as required by 2.1.6, provided the Administration is satisfied that there is no practical alternative to the fitting of such a second pipe and that, having regard to the additional subdivision provided in the forepeak, the safety of the ship is maintained. 2.1.8Where a long forward superstructure is fitted the collision bulkhead shall be extended weathertight to the deck next above the bulkhead deck. The extension need not be fitted directly above the bulkhead below provided it is located within the limits prescribed in 2.1.1 or 2.1.3 with the exception permitted by 2.1.9 and that the part of the deck which forms the stepismadeeffectivelyweathertight. The extension shallbe so arranged as to preclude the possibilityofthebowdoorcausing damage to it in the case of damage to, or detachment of, a bow door. 2.1.9Where bow doors are fitted and a sloping loading ramp forms part of the extension of the collision bulkhead above the bulkhead deck, the ramp shall be weathertight over its complete length. In cargo ships the part of the ramp which is more than 2,3 mabove the bulkhead deck may extend forward of the limits specified in 2.1.1 or 2.1.3 Ramps not meeting the above requirements shall be disregarded as an extension of the collision bulkhead. 2.1.10 The number of openings in the extension of the collision bulkhead above the bulkhead deck shall be restricted to the minimum compatible with the design and normal operation of the ship. All such openings shall be capable of being BKI - Rules for Hull - 2014
- 175. Section 11 - Watertight Bulkheads A 11-3/8 closed weathertight. 2.2 Stern tube and remaining watertight bulkheads 2.2.1Bulkheads shall be fitted separating the machinery space from cargo and accommodation spaces forward and aft and made watertight up to the bulkhead deck. In passenger ships an afterpeak bulkhead shall also be fitted and made watertight up to the bulkhead deck. The afterpeak bulkhead may, however, be stepped below the bulkhead deck, provided the degree of safety of the ship as regards subdivision is not thereby diminished. 2.2.2In all cases stern tubes shall be enclosed inwatertight spaces of moderate volume. In passenger ships the stern gland shall be situated in a watertight shaft tunnel or other watertight space separate from the stern tube compartment and of such volume that, if flooded by leakage through the stern gland, the bulkhead deck will not be immersed. In cargo ships other measures to minimize the danger of water penetrating into the ship in case of damage to stern tube arrangements may be taken at the discretion of the Administration. 3. Openings in watertight bulkheads 3.1 General 3.1.1Type and arrangement of doors are to be submitted for approval. 3.1.2Regarding openings in the collision bulkhead see 2.1.5 and 2.1.10. 3.1.3In the other watertight bulkheads, watertight doors may be fitted. Watertight doors required to be open at sea are to be of the sliding type and capable of being operated both at the door itself, on both sides, and from an accessible position above the bulkhead deck. Means are to be provided at the latter position to indicate whether the door is open or closed, as well as arrows indicating the direction in which the operating gear is to be operated. Watertight doors may be of the hinged type if they are always intended to be closed during navigation. Such doors are to be framed and capable of being secured watertight by handle-operated wedges which are suitably spaced and operable at both sides. 3.1.4On ships for which proof of floatability in damaged condition is to be provided, hinged doors are permitted above the most unfavourable damage waterline for the respective compartment only. Deviating and additional requirements hereto are given in Chapter II-1, Reg. 13-1 of SOLAS (as amended by MSC.216 (82)). 3.1.5For bulkhead doors in passenger ships, see Section.29-I, C. 3.1.6Watertight doors are to be sufficiently strong and of an approved design. The thickness of plating is not to be less than the minimum thickness according to B.2. 3.1.7Openings for watertight doors in the bulkheads are to be effectively framed such as to facilitate proper fitting of the doors and to guarantee perfect watertightness. 3.1.8Beforebeingfitted,thewatertightbulkheaddoors,togetherwiththeirframes,aretobetestedbyaheadofwatercorresponding to the bulkhead deck height. After having been fitted, the doorsare to be hose- or soap-tested for tightness and to be subjected to an operational test. Deviating and additional requirementsheretoaregiveninChapter II-1 Reg. 16 of SOLASas amended. 3.2 Hinged doors Hinged doors are to be provided with rubber sealings and toggles or other approved closing appliances which guarantee a sufficient sealing pressure. The toggles and closing appliances are to be operable from both sides of the bulkhead. Hinges are to have oblong holes. Bolts and bearings are to be of corrosion resistant material. A warning notice requiring the doors to be kept closed at sea is to be fitted at the doors. 3.3 Sliding doors Sliding doors are to be carefully fitted and are to be properly guided in all positions. Heat sensitive materials are not to be used in systems which penetrate watertight subdivision bulkheads, where deterioration of such systems in the event of fire would impair the watertight integrity of the bulkheads. BKI - Rules for Hull - 2014
- 176. A, B Section 11 - Watertight Bulkheads11-4/8 The closing mechanism is to be safely operable from each side of the bulkhead and from above the freeboard deck. If closing ofthedoorcannotbeobservedwithcertainty,anindicatoristobefittedwhichshows,ifthedoorisclosedoropen;theindicator is to be installed at the position from which the closing mechanism is operated. 3.4 Penetrations through watertight bulkheads Where bulkhead fittings are penetrating watertight bulkheads, care is to be taken to maintain water tightness by observation of Chapter II-1 Reg. 12 of SOLAS as amended. For penetrations through the collision bulkhead, 2.1.6 is to be observed. B. Scantlings 1. General, Definitions 1.1 Where holds are intended to be filled with ballast water, their bulkheads are to comply with the requirements of Section 12. 1.2 Bulkheads of holds intended to be used for carrying ore are to comply with the requirements of Section 23, as far as their strength is concerned. 1.3 Definitions tK = corrosion addition according to Section 3, K. a = spacing of stiffeners [m] R = unsupported span [m], according to Section 3, C. p = 9,81 @ h [kN/m2 ] h = distance from the load centre of the structure to a point 1 m above the bulkhead deck at the ship side, for the collision bulkhead to a point 1 m above the upper edge of the collision bulkhead at the ship side. For cargo ships with proven damage stability see Section 36, E.2. For the definition of "load centre" see Section.4. A.2.1. cp, cs = coefficients according to Table 11.2 f = ReH = minimum nominal upper yield point [N/mm2 ] according to Section 2, B.2. Table 11.2 - Coefficients cp and cs Coefficient cp and cs Collision bulkhead Other bulkheads Plating cp Stiffeners, corrugated bulkhead elements cs: in case of constraint of both ends 0,33 @ f 0,265 @ f cs: in case of simply support of one end and constraint at the other end 0,45 @ f 0,36 @ f cs: both ends simply supported 0,66 @ f 0,53 @ f For the definition of "constraint" and "simply supported", see Section.3. D.1. 2. Bulkhead plating 2.1 The thickness of the bulkhead plating is not to be less than : t = [mm] tmin = [mm] BKI - Rules for Hull - 2014
- 177. Section 11 - Watertight Bulkheads B 11-5/8 For ships with large deck openings according to Section.5, F.1.2, the plate thickness of transverse bulkheads is not to be less than: t = c @ + tK [mm] where )R = distancefromthemidofholdbeforetothemidofholdaftoftheconsideredtransversebulkhead or supporting bulkhead [m] a, b = spacing of stiffeners [m] tK = corrosion addition [mm] according to Section 3, K. ReH = nominal upper yield stress of material [N/mm2 ] according to Section 2, B.2. F1 = correction factor according to Section 3, F.1. c = 13 in general = 15 below z = 0,2 H and above 0,8 H and generally in the fore ship before x/L = 0,8 2.2 In small ships, the thickness of the bulkhead plating need not exceed the thickness of the shell plating for a frame spacing corresponding to the stiffener spacing. 2.3 The stern tube bulkhead is to be provided with a strengthened plate in way of the stern tube. 2.4 In areas where concentrated loads due to ship manoeuvres at terminals, may be expected, the buckling, strength of bulkhead plate fields directly attached to the side shell, is to be examined according to Section 9, B.4.4 and 4.5. 2.5 When determining the bulkhead scantlings of tanks, connected by cross-flooding arrangements, the increase in pressure head at the immerged side that may occur at maximumheeling in the damaged condition shall be taken into account. 3. Stiffeners 3.1 The section modulus of bulkhead stiffeners is not to be less than: W = [cm3 ] 3.2 In horizontal part of bulkheads, the stiffeners are also to comply with the rules for deck beams according to Section 10. 3.3 Thescantlingsofthebracketsaretobedeterminedindependence ofthesectionmodulusofthestiffenersaccording to Section 3, D.2. If the length of the stiffener is 3,5 m and over, the brackets are to extend to the next beam or the next floor. 3.4 Unbracketed bulkhead stiffeners are to be connected to the decks by welding. The length of weld is to be at least 0,6 x depth of the section. 3.5 If the length of stiffeners between bulkhead deck and the deck below is 3 m and less, no end attachment according to 3.4 is required. In this case the stiffeners are to be extended to about 25 mm from the deck and sniped at the ends. (See also Section 3, C.3.) 3.6 Bulkhead stiffeners cut in way of watertight doors are to be supported by carlings or stiffeners. 4. Corrugated bulkheads 4.1 The plate thickness of corrugated bulkheads is not to be less than required according to 2.1. For the spacing a, the greater one of the values b or s [m] according to 4.3 is to be taken. 4.2 The section modulus of a corrugated bulkhead element is to be determined according to 3.1. For the spacing a, the width of an element e, [m] according to 4.3 is to be taken. For the end attachment see Section 3, D.4. 4.3 Theactualsectionmodulusofacorrugatedbulkheadelementistobe assessedaccordingtothefollowingformulae: BKI - Rules for Hull - 2014
- 178. B Section 11 - Watertight Bulkheads11-6/8 W = t @ d [cm3 ] where, carling or similar elements can not be fitted in line with the web strips W = t @ d (d + t) [cm3 ] e = width of element [cm] b = breadth of face plate [cm] s = breadth of web plate [cm] d = distance between face plates [cm] t = plate thickness [cm] " 45E Fig. 11.2 Element of corrugated bulkhead 4.4 For watertight bulkheads of corrugated type on ship according to Section 5, G. See Section 23, E. 5. Primary Supporting Members 5.1 General Primary supporting members are to be dimensioned using direct calculation as to ensure the stress criteria according to 5.3.1 for normal operation and the criteria according to 5.3.2 if any cargo hold is flooded. Regarding effective breadth and buckling proof in each case Section 3, E. and F. has to be observed. In areas with cut-outs 2nd-order bending moments shall be taken into account. 5.2 Load assumptions 5.2.1 Loads during operation Loads during operation are the external water pressure, see Section 4, and the loads due to cargo and filled tanks, see Section 17, B.1.7, Section 21, G. and if relevant depending on the deck opening Section 5, F. 5.2.2 Loads in damaged condition The loads in case of hold flooding result from 1.3 considering Section 36, D.2. 5.3 Strength criteria 5.3.1 Load case "operation" With loads according to 5.2.1 the following permissible stresses are to be used : Fv = # [N/mm2 ] FN = normal stress, FN # [N/mm2 ] J = shear stress, J # [N/mm2 ] k = material factor according Section 2, B.2. If necessary Section 5, F.2. shall be observed in addition. BKI - Rules for Hull - 2014
- 179. Section 11 - Watertight Bulkheads B 11-7/8 5.3.2 Load case "hold flooding" The thickness of webs shall not be smaller than: tw = [mm] Jperm = 727 [N/mm2 ] Q = shear force [kN] hw = height of web [mm] a, b = lengths of stiffeners of the unstiffened web field, where hw $ b # a 5.3.3 Dimensioning of Primary Supporting Members For dimensioning of primary supporting members plastic hinges can be taken into account. Thiscanbedoneeitherbyanon-linearcalculationofthetotalbulkheadorbyalineargirdergrillagecalculationoftheidealized bulkhead. When a linear girder grillage calculation is done, only those moments and shear forces are taken as boundary conditions at the supports, which can be absorbed by the relevant sections at these locations in full plastic condition. The plastic moments [kNm] are calculated by: Mp = c = 1,1 for the collision bulkhead = 1,0 for cargo hold bulkheads The plastic shear forces [kN] are calculated by : Qp = For the field moments and shear forces resulting thereof the sections are defined in such a way that the condition Fv # ReH is fulfilled. The plastic section moduli are to be calculated as follows: Wp = Ai @ epi [cm3 ] epi = distance [mm] of the centre of the partial area Ai fromthe neutral axis of the yielded section. The neutral axis shall not be taken in a position lower than the lowest point of the web. Ai = effective partial area [mm2 ] considering Section.3, F.2.2. In this connection the area As of webs transferring shear shall not be taken into account. That part of the web height related to shear transfer shall not be less than: )hw = hw @ twa = as built thickness of the web $ tw Where girders are built up by partial areas Ai with different yield stress ReHi the plastic moments are calculated by: Mp = [kNm] BKI - Rules for Hull - 2014
- 180. B, C Section 11 - Watertight Bulkheads11-8/8 The plastic shear forces are: Qp = [kN] 6. Watertight longitudinal structures The plating and stiffeners of watertight longitudinal structures shall be dimensioned according to Table 11.2, column "Other bulkheads". C. Shaft Tunnels 1. General 1.1 Shaftandstuffingboxaretobeaccessible.Whereoneormorecompartmentsaresituatedbetweensterntubebulkhead and engine room, a watertight shaft tunnel is to be arranged. The size of the shaft tunnel is to be adequate for service and maintenance purposes. 1.2 The access opening between engine room and shaft tunnel is to be closed by a watertight sliding door complying with the requirements according to A.3.3. For extremely shortshaft tunnels watertight doorsbetweentunnelandengineroom may be dispensed with subject to special approval. In this connection see also SOLAS 74, Chapter II-1, Regulation 11/8 as amended. 1.3 Tunnel ventilators and the emergency exit are to be constructed watertight up to the freeboard deck. 2. Scantlings 2.1 The plating of the shaft tunnel is to be dimensioned as for a bulkhead according to B.2.1. 2.2 The plating of the round part of tunnel tops may be 10 % less in thickness. 2.3 In the range of hatches, the plating of the tunnel top is to be strengthened by not less than 2 mm unless protected by a ceiling. On container ships this strengthening can be dispensed with. 2.4 The section modulus of shaft tunnel stiffeners is to be determined according to B.3.1. 2.5 Horizontal parts of the tunnel are to be treated as horizontal parts of bulkheads and as cargo decks respectively. 2.6 Shaft tunnels in tanks are to comply with the requirements of Section 12. BKI - Rules for Hull - 2014
- 181. Section 12 - Tank Structures A 12-1/10 Section 12 Tank Structures A. General Note The arrangement and subdivision of fuel oil tanks has to be in compliance with MARPOL, Annex I, Reg. 12 A "Oil Fuel Tank Protection". 1. Subdivision of tanks 1.1 In tanks extending over the full breadth of the ship intended to be used for partial filling, (e.g. oil fuel and fresh water tanks), at least one longitudinal bulkhead is to be fitted, which may be a swash bulkhead. 1.2 Where the forepeak is intended to be used as tank, at least one complete or partial longitudinal swash bulkhead is to be fitted, if the tank breadth exceeds 0,5 B or 6 m, whichever is the greater. When the afterpeak is intended to be used as tank, at least one complete or partial longitudinal swash bulkhead is to be fitted. The largest breadth of the liquid surface should not exceed 0,3 B in the aft peak. 1.3 Peak tanks exceeding 0,06 L or 6 m in length, whichever is greater, shall be provided with a transverse swash bulkhead. 2. Air, overflow and sounding pipes Each tank is to be fitted with air pipes, overflow pipes and sounding pipes. The air pipes are to be led to above the exposed deck. The arrangement is to be such as to allow complete filling of the tanks. The height from the deck to the point where the water way have access to be at least 760 mm on the freeboard deck and 450 mm on a superstructure deck. See also Section 21, E. The sounding pipes are to b e led to the bottom of the tanks (see also Rules for Machinery Installations, Volume III, Section 11). 3. Forepeak tank Oil is not to be carried in a forepeak tank or a tank forward of the collision bulkhead . See also SOLAS 74, Chapter II-2, Reg. 15.6 and MARPOL 73/78, Annex I, Reg. 14.4. 4. Cross references 4.1 Where a tank bulkhead forms part of a watertight bulkhead, its strength is not to be less than required by Section 11. 4.2 For pumping and piping, see also Rules for Machinery Installations, Volume III, Section 11. For Oil fuel tanks see also Rules for Machinery Installations, Volume III, Section 10. For tanks in the double bottom, see Section 8, B.5. 4.3 For cargo oil tanks see Section 24. 4.4 For dry cargo holds which are also intended to be used as ballast water tanks, see C.2. 4.5 For testing of tanks, see H. 4.6 Where tanks are provided with cross flooding arrangements the increase of the pressure head is to be taken into consideration (see also Section 29-I, J. and Section 36, G.). 5. Separation of fuel oil tanks from tanks for other liquids 5.1 Fuel oil tanks are to be separated fromtanks for lubricating oil, hydraulic oil, thermal oil, vegetable oil, feedwater, BKI - Rules for Hull - 2014
- 182. A Section 12 - Tank Structures12-2/10 condensate water and potable water by cofferdams1) . 5.2 Upon special approval on small ships the arrangement of cofferdams between oil fuel and lubricating oil tanks may be dispensed with provided that: .1 the common boundary is continuous, i.e. it does not abut at the adjacent tank boundaries, see Fig. 12.1 Where the common boundary cannot be constructed continuously according to Fig. 12.1, the fillet welds on both sides of the common boundary are to be welded in two layers and the throat thickness is not to be less than 0,5 @ t (t = plate thickness); Fig. 12.1 - Continuous common boundary replacing a cofferdam .2 stiffeners or pipes do not penetrate the common boundary; .3 the corrosion allowance tK for the common boundary is not less than 2,5 mm. 5.3 Fuel oil tanks adjacent to lubricating oil circulation tanks are not permitted. 5.4 For fuel tanks which are heated up to a temperature which is higher than the flash point – 10 °C of the relevant fuel, Rules for Machinery Installations, Volume III, Section.10, B.5.is to be observed specifically. 6. Tanks for heated liquids 6.1 Where heated liquids are intended to be carried in tanks, acalculationofthermalstressesis required, if the carriage temperature of the liquid exceeds the following values : T = 65EC in case of longitudinal framing, = 80EC in case of transverse framing. 6.2 The calculations are to be carried out for both temperatures, the actual carriage temperature and the limit temperature T according to 6.1. The calculations are to give the resultant stresses in the hull structure based on a sea water temperature of 0EC and an air temperature of 5EC. Constructionalmeasuresand/orstrengtheningswillberequiredonthebasisoftheresultsofthecalculationforbothtemperatures. 7. Minimum thickness 7.1 The thickness of all tank structures is not to be less than the following minimum value : tmin = 5,5 + 0,02 L [mm] 7.2 For fuel oil, lubrication oil and fresh water tanks tmin need not be taken greater than 7,5 mm 7.3 For ballast tanks of dry cargo ships tmin need not be taken greater than 9,0 mm. 7.4 For oil tankers see Section 24, A.14. 1) For Indonesian flag ship, the cofferdams are also required between accommodation spaces and oil tanks. BKI - Rules for Hull - 2014
- 183. Section 12 - Tank Structures A 12-3/10 8. Plating and stiffeners in the propeller area and in the engine room 8.1 General Fromavibrationpointofviewshellandtankstructuresinthevicinityofthepropeller(s)andthemainengineshouldbedesigned such that the design criteria defined in 8.3 to 8.5 are fulfilled (see also Section 6, F.1 and Section 8, A.1.2.3). 8.2 Definitions fplate 2) = lowestnaturalfrequencyofisotropicplatefieldunderconsiderationofadditionaloutfittingandhydrodynamic masses [Hz] fstiff 2) = lowest natural frequency of stiffener under consideration of additional outfitting and hydrodynamic masses [Hz] dp = propeller diameter [m] r = distance of plate field or stiffener to 12 o'clock propeller blade tip position [m] dr = ratio " = flare angle of frame section in propeller plane measured between a vertical line and the tangent to the bottom shell plating n = maximum propeller shaft revolution rate [1/min] z = number of propeller blades fblade = propeller blade passage excitation frequency at n [Hz] = [Hz] ne = maximum main engine revolution rate [1/min] nc = number of cylinders of main engine kstroke = number indicating the type of main engine = 1,0 for 2-stroke (slow-running) main engines = 0,5 for 4-stroke (medium speed) main engines 3) fignition = main engine ignition frequency at ne = [Hz] 8.3 Shell structures in propeller area Plate fields and stiffeners of shell structures in vicinity of the propeller(s) within dr = 3 should fulfil the following frequency criteria: for " $ 60o for " < 60o dr needs not to be taken less than 1,0. 8.4 Tank structures in propeller area Forvesselwithasinglepropeller,platefieldsandstiffenersoftankstructureswithindr =5shouldfulfilthefollowingfrequency criteria : 2) The natural frequencies of plate fields and stiffeners can be estimated by approved computer program 3) The number is valid for in-line engines. The ignition frequency for V-engines depends on the V-angle of the cylinder banks and can be obtained from the engine manufacturer. BKI - Rules for Hull - 2014
- 184. A, B Section 12 - Tank Structures12-4/10 for " $ 60o for " < 60o dr needs not to be taken less than 1,3. 8.5 Tank structures in main engine area For vessels with a single propeller, plate fields and stiffeners of tanks located in the engine room should at all filling states fulfil the frequency criteria as summarized in Table 12.1. Generally, direct connections between transverse engine top bracings and tank structures shall be avoided. Pipe fittings at tank walls etc. shall be designed in such a way that the same frequency criteria as given for plates are fulfilled. B. Scantlings 1. Definitions k = material factor according to Section 2, B.2. a = spacing of stiffeners or load width [m] R = unsupported span [m] according to Section 3, C. p = load p1 or pd [kN/m2 ] according to Section 4, D.; the greater load to be taken. For tank structures of tanks adjacent to the shell the pressure p below Tmin need not be larger than : p = [kN/m2 ] Tmin = smallest design ballast draught [m] z = distance of structural member above base line [m] p2 = load [kN/m2 ] according to Section 4, D.1. tK = corrosion addition according to Section 3, K. h = filling height of tank [m] et = characteristic tank dimension Rt or bt [m] Rt = tank length [m] bt = tank breadth [m] FpR = [N/mm2 ] FL = membrane stress at the position considered [N/mm2 ] according to Section 5,D.1 JL = shear stress [N/mm2 ] at the position considered see also Section 5,D.1. nf = 1,0 for transverse stiffening = 0,83 for longitudinal stiffening For the terms "constraint" and "simply supported" see Section 3, D. BKI - Rules for Hull - 2014
- 185. Section 12 - Tank Structures B 12-5/10 Table 12.1 - Frequency criteria Engine type Mounting type Application area Frequency criteria Slow speed Rigid Tanks within engine room fplate > 1,2 . fignition fstiff > 1,2 . fignition and fplate < 1,8 . fignition or fplate > 2,2 . fignition Medium speed Rigid or semi-resilient Tanks within engine room fplate < 0,8 . fignition or fplate > 1,2 . fignition and fstiff < 0,8 . fignition or fstiff > 1,2 . fignition Resilient Tanks within engine length up to next platform deck above inner bottom fplate < 0,9 . fignition or fplate < 1,1 . fignition 2. Plating 2.1 The plate thickness is not to be less than: t1 = 1,1 @ a @ + tK [mm] t2 = 0,9 @ a @ + tK [mm]. 2.2 Abovetherequirementsspecifiedin2.1thethicknessoftankboundaries(includingdeckandinnerbottom)carrying also normal and shear stresses due to longitudinal hull girder bending is not to be less than : t = [mm] 2.3 Proof of plating of buckling strength of longitudinal and transverse bulkheads is to be carried out according to Section 3, F. For longitudinal bulkheads the design stresses according to Section 5, D.1. and the stresses due to local loads are to be considered. 3. Stiffeners and girders 3.1 Stiffeners and girders, which are not considered as longitudinal strength members 3.1.1The section modulus of stiffeners and girders constrained at their ends, is not to be less than: W1 = 0,55 @ a @ R2 @ p @ k [cm3 ] W2 = 0,44 @ a @ R2 @ p2 @ k [cm3 ]. Where one or both ends are simply supported, the section moduli are to be increased by 50%. The shear area of the girder webs is not to be less than: Aw1 = 0.05 @ a @ R @ p @ k [cm2 ] Aw2 = 0,04 @ a @ R @ p2 @ k [cm2 ]. Aw2 is to be increased by 50 % at the position of constraint for a length of 0,1 R. The buckling strength of the webs is to be checked according to Section 3, F. 3.1.2Wherethescantlingsofstiffenersandgirdersaredeterminedaccordingtostrengthcalculations,thefollowingpermissible stress values apply : BKI - Rules for Hull - 2014
- 186. B Section 12 - Tank Structures12-6/10 S if subjected to load p : Fb = [N/mm2 ] J = [N/mm2 ] Fv = [N/mm2 ] S if subjected to load p2 : Fb = [N/mm2 ] J = [N/mm2 ] Fv = [N/mm2 ] 3.2 Stiffeners and girders, which are to be considered as longitudinal strength members 3.2.1The section moduli and shear areas of horizontal stiffeners and girders are to be determined according to Section 9, B.3.1 as for longitudinals. In this case for girders supporting transverse stiffeners the factors m = 1 and ma = 0 are to be used. 3.2.2 Regarding buckling strength of girders the requirements of 2.3 are to be observed. 3.3 The scantlings of beams and girders of tank decks are also to comply with the requirements of Section 10. 3.4 For frames in tanks, see Section 9, A.2.2. 3.5 ThestiffenersoftankbulkheadsaretobeattachedattheirendsbybracketsaccordingtoSection3,D.2.Thescantlings of the brackets are to be determined according to the section modulus of the stiffeners. Brackets have to be fitted where the length of the stiffeners exceeds 2 m. The brackets of stiffeners are to extend to the next beam, the next floor, the next frame, or are to be otherwise supported at their ends. 3.6 Where stringersoftransverse bulkheads are supported at longitudinal bulkheads or at the side shell, the supporting forcesofthesestringersaretobeconsideredwhendeterminingthe shear stress in the longitudinal bulkheads. Likewise, where vertical girders of transverse bulkheads are supported at deck or inner bottom, the supporting forces of these vertical girders are to be considered when determining the shear stresses in the deck or inner bottom respectively. The shear stress introduced by the stringer into the longitudinal bulkhead or side shell may be determined by the following formulae: = [N/mm2 ]τSt Pst = supporting force of stringer or vertical girder [kN] bSt = breadth of stringer or depth of vertical girder including end bracket (if any) [m] at the supporting point t = see 2.2 The additional shear stress is to be added to the shear stress JL due to longitudinal bending according to SectionτSt 5, D.1. in the following area: – 0,5 m on both sides of the stringer in the ship's longitudinal direction – 0,25 . bSt above and below the stringer Thereby the following requirement shall be satisfied : BKI - Rules for Hull - 2014
- 187. Section 12 - Tank Structures B, C 12-7/10 4. Corrugated bulkheads 4.1 Theplatethicknessesofcorrugatedbulkheadsaswellastherequiredsectionmoduliofcorrugatedbulkheadelements are to be determined according to 2. and 3., proceeding analogously to Section 11, B.4. The plate thickness is not to be less than tmin, according to A.7, or S if subjected to load p tcrit = [mm] S if subjected load p2 tcrit = [mm] FD = compressive stress [N/mm2 ] b = breadth of face plate strip [mm] 4.2 For the end attachment Section 3, D.4. is to be observed. 5. Thickness of clad plating 5.1 Where the yieldpointofthe claddingisnotless thanthat of the base material the plate thickness is to be determined according to 2.1. 5.2 Where the yield point of the cladding is less than that of the base material the plate thickness is not to be less than: t1 = 0,55 @ a [mm] t2 = 0,45 @ a [mm] for one side clad steel: A = 0,25 S for both side clad steel: A = 0,25 S t = plate thickness including cladding [mm] tp = thickness of the cladding [mm] r = Rep = minimum nominal upper yield point of the cladding [N/mm2 ] at service temperature ReH = minimum nominal upper yield point of the base material [N/mm2 ] according to Section 2, B.2. 5.3 The plate thicknesses determined in accordance with 5.1 and 5.2 respectively may be reduced by 0,5 mm. For chemicaltankershoweverthereductions as perRulesforShipsCarryingDangerousChemicalsinBulk,VolumeX,Section.4, 4 – 0.1.3 apply. C. Tanks with Large Lengths or Breadths 1. General Tanks with lengths Rt > 0,1 L or breadths bt > 0,6 B (e.g. hold spaces for ballast water) which are intended to be partially filled, are to be investigated to avoid resonance between theliquidmotionandthepitchorrollmotionoftheship.Ifnecessary, BKI - Rules for Hull - 2014
- 188. C, D Section 12 - Tank Structures12-8/10 critical tank filling ratios are to be avoided. The ship's periods of pitch and roll motion as well as the natural periods of the liquid in the tank may be determined by the following formulae: Natural period of liquid in tank : TR,b = [s] f = hyperbolic function as follows: = tanh Period of wave excited maximum pitch motion : Ts = [s] = ahead speed of ship [kn] as defined in Section 1, H.5. Period of roll motion : Tr = [s] cr = 0,78 in general = 0,70 for tankers in ballast . 0,07 @ B in general . 0,12 @ B for tankers and bulk carriers. 2. Hold spaces for ballast water Inadditiontotherequirementsspecifiedunder1.aboveforholdspacesofdrycargoshipsandbulkcarriers,whichareintended to be filled with ballast water, the following is to be observed: .1 For hold spaces only permitted to be completely filled, a relevant notice will be entered into the Certificate. .2 Adequate venting of the hold spaces and of the hatchway trunks is to be provided. .3 For frames also Section 9, A.2.2 is to be observed. D. Vegetable Oil Tanks 1. Further to the regulations stipulated under A. and B. for vegetable oil tanks, the following requirements are to be observed. 2. Tanks carrying vegetable oil or similar liquids, the scantlings of which are determined according to B., are to be either fully loaded or empty. A corresponding note will be entered into the Certificate. Thesetanksmaybepartiallyfilledprovided they are subdivided according to A.1.2. Fillingratiosbetween70and90%should be avoided. 3. Intankscarryingvegetableoilorsimilarliquidssufficientairpipesaretobefittedforpressureequalizing.Expansion trunks of about 1 % of the tank volume are to be provided. Where the tank is subdivided by at least one centre line bulkhead, 3% of the tank may remain empty and be used as expansion space. BKI - Rules for Hull - 2014
- 189. Section 12 - Tank Structures E, F, G 12-9/10 E. Detached Tanks 1. General 1.1 Detached tanks are to be adequately secured against forces due to the ship's motions. 1.2 Detached tanks in hold spaces are also to be provided with anti floatation devices. It is to be assumed that the hold spaces are flooded to the load waterline. The stresses in the anti floatation devices caused by the floatation forces are not to exceed the material's yield stress. 1.3 Detached oil fuel tanks should not be installed in cargo holds. Where such an arrangement cannot be avoided, provision is to be made to ensure that the cargo cannot be damaged by leakage oil. 1.4 Fittings and pipings on detached tanks are to be protected by battens, and gutterways are to be fitted on the outside of tanks for draining any leakage oil. 2. Scantlings 2.1 The thickness of plating of detached tanks is to be determined according to B.2.1 using the formulae for t1 and the pressure p as defined in 2.2. 2.2 The section modulus of stiffeners of detached tanks is not to be less than: W = c @ a @ R2 @ p @ k [cm3 ] c = 0,36 if stiffeners are constrained at both ends = 0,54 if one or both ends are simply supported p = 9,81 @ h [kN/m2 ] h = head measured from the load centre of plate panel or stiffener respectively to the top of overflow; the height of overflow is not to be taken less than 2,5 m. 2.3 For minimum thickness the requirements of A.7 apply in general. F. Potable Water Tanks 1. Potablewatertanksshallbeseparatedfromtankscontainingliquidsotherthanpotablewater,ballastwater,distillate or feed water. 2. In no case sanitary arrangement or corresponding piping are to be fitted directly above the potable water tanks. 3. Manholes arranged in the tank top are to have sills. 4. If pipes carrying liquids other than potable water are to be led through potable water tanks, they are to be fitted in a pipe tunnel. 5. Air and overflow pipes of potable water tanks are to be separated from pipes of other tanks. G. Swash Bulkheads 1. The total area of perforation shall not be less than 5% and should not exceed 10% of the total bulkhead area. 2. The plate thickness shall, in general, be equal to the minimum thickness according to A.7. Strengthenings may be required for load bearing structural parts. The free lower edge of a wash bulkhead is to be adequately stiffened. 3. The section modulus of the stiffeners and girders is not to be less than W1 as per B.3., however, in lieu of p the load pd according to Section 4, D.2., but disregarding pv is to be taken. BKI - Rules for Hull - 2014
- 190. G, H Section 12 - Tank Structures12-10/10 4. For swash bulkheads in oil tankers see also Section 24, D. H. Testing for Tightness 1. Testingofoilfuel,ballast,trimming,feedwater,freshwaterandanti-rollingtanksistobeeffectedbyacombination of a leak test by means of air pressure and an operational test by means of water or the liquid for which the tank is intended to be used. The air pressure is not to exceed 0,2 bar gauge. The increased risk of accident while the tanks are subjected to the air pressure is to be observed. Butt welds made by approved automatic or semiautomatic processes on erection welds need not be tested, provided that these weldsarecarefullyvisuallyexaminedandarefreeofrepairs. The results of the non-destructive examinations made at random to the satisfaction of the Surveyor shall not reveal significant defects. If there is evidence from inspection results that the quality of these welds has been downgraded significantly, the extent of the leak testing may be increased to the Surveyor's discretion. 2. Where one tank boundary is formed by the ship's shell, the leak test is to be carried out before launching. For all other tanks leak testing may be carried out after launching. Erection welds as well as welds of assembly openings are to be coated 4) after the leak test is carried out. This applies also to manual weld connections of bulkheads with the other tanks boundaries and of collaring arrangements at intersections of tank boundaries and e.g. frames, beams, girders, pipes etc. If it is ensured that in adjacent tanks the same type of liquid is carried, e.g. in adjacent ballast tanks, the above mentioned weld connections may be coated 3) prior to the leak test. All other welded connections in tank boundaries may be coated prior to the leak test if it is ensured by suitable means (e.g. by visual examination of the welded connections) that the connections are completely welded and the surfaces of the welds do not exhibit cracks or pores. 3. Where the tanks are not subjected to-the leak test as per 2. but are leak tested with water the bulkheads area in general, to be tested from one side. The testing should be carried out prior to launching or in the dock. Subject to approval by BKI, the test may also be carried out after launching. Water testing may be carried out after application of a coating3) , provided that during the visual inspection as per 2. above deficiencies are not noted. The test head shall correspond to a head of water of 2,5 m above the top of tank or to the top of overflow or air pipe, whichever is the greater. 4. Theoperationaltestmaybecarriedoutwhentheshipisafloatorduringthetrialtrip.Foralltankstheproperfunctioning of filling and suction lines and of the valves as well as functioning and tightness of the vent, sounding and overflow pipes is to be tested. 5. For testing of cargo tanks see Section 24, A.16. 4) Shop primers are not regarded as a coating within the scope of these requirements. BKI - Rules for Hull - 2014
- 191. Section 13 - Stem and Sternframe Structures A, B, C 13-1/8 Section 13 Stem and Sternframe Structures A. Definitions ReH = minimum nominal upper yield point [N/mm2 ] according to Section 2, B.2. k = material factor according to Section 2, B.2.1, for cast steel k = kr according to Section 14, A.4.2 CR = rudder force [N] according to Section 14, B. 1. B1 = support force [N] according to Section 14, C.3. tK = corrosion addition [mm] according to Section 3,K. aB = spacing of fore-hooks [m] B. Stem 1. Bar stem 1.1 The cross sectional area of a bar stem below the load waterline is not to be less than: Ab = 1,25 @ L [cm2 ]. 1.2 Starting from the load waterline, the sectional area of the bar stem may be reduced towards the upper end to 0,75 Ab. 2. Plate stem and bulbous bows 2.1 The thickness is not to be less than: t = (0,6 + 0,4 aB) @ (0,08 L + 6) [mm] tmax = 25 [mm] The plate thickness shall not be less than the required thickness according to Section 6, C.2. The extension R of the stem plate from its trailing edge aftwards shall not be smaller than: R = 70 @ [mm] Dimensioning of the stiffening has to be done according to Section 9. 2.2 Starting from 600 mm above the load waterline up to T + co, the thickness may gradually be reduced to 0,8t. 2.3 Plate stems and bulbous bows have to be stiffened by fore-hooks and/or cant frames. In case of large and long bulbous bows, see Section 9, A.5.3.3. C. Sternframe 1. General 1.1 Propeller post and rudder post are to be led into the hull in their upper parts and connected to it in a suitable and efficient manner. In way of the rudder post the shell is to be strengthened according to Section 6, F. Due regard is to be paid to the design of the aft body, rudder and propeller well in order to minimize the forces excited by the propeller. 1.2 The following value is recommended for the propeller clearance d0,9 related to 0,9 R (see Fig 13.1): BKI - Rules for Hull - 2014
- 192. C Section 13 - Stem and Sternframe Structures13-2/8 [m] R = propeller radius [m] v0 = ship's speed, see Section 1, H.5. [knot] n = number of propeller revolutions per minute D = maximum displacement of ship [ton] dp = propeller diameter [m] ( = skew angle of the propeller [E], see Fig. 13.2 zB = height of wheelhouse deck above weather deck [m] xF = distance of deckhouse front bulkhead from aft edge of stern [m], see Fig. 13.1. Fig. 13.1 - Propeller clearance d0,9 Fig. 13.2 - Skew angle 1.3 For single screw ships, the lower part of the stern frame is to be extended forward by at least 3 times the frame spacing from fore edge of the boss, for all other ships by 2 times the frame spacing from after edge of the stern frame. 1.4 The stern tube is to be surrounded by the floor plates or, when the ship's shape is too narrow to be stiffened by internal rings. Where no sole piece is fitted the internal rings may be dispensed with. 1.5 The plate thickness of sterns of welded construction for twin screw vessels shall not be less than: t = (0,07 L + 5,0) [mm] tmax = 22 [mm]. 2. Propeller post 2.1 The scantlings of rectangular, solid propeller posts are to be determined according to the following formulae: R = 1,4 L + 90 [mm] b = 1,6 L + 15 [mm] Where other sections than rectangular ones are used, their section modulus is not to be less than that resulting from R and b. 2.2 Thescantlingsofpropeller posts of welded constructionare to be determined according to the followingformulae: R = 50 [mm] b = 36 [mm] t = 2,4 [mm]. 2.3 Where the cross sectional configuration is deviating from Fig. 13.3 and for cast steel propeller posts the section modulus of the cross section related to the longitudinal axis is not to be less than: BKI - Rules for Hull - 2014
- 193. Section 13 - Stem and Sternframe Structures C 13-3/8 Wx = 1,2 @ L1,5 @ k [cm3 ] Fig. 13.3 Propeller post Note With single-screw ships having in the propeller region above the propeller flaring frames of more than " = 75° the thickness of the shell should not be less than the thickness of the propeller stem. For " # 75° the thickness may be 0,8 t. In no case the thickness shall be less than the thickness of the side shell according to Section 6. This recommendation applies for that part of the shell which is bounded by an assumed sphere the centre of which is located at the top of a propeller blade in the twelve o’clock position and the radius of which is 0,75 @ propeller diameter. Sufficient stiffening should be arranged, e.g. by floors at each frame and by longitudinal girders. 2.4 The wal l thickness o f the boss in the propeller post in its finished condition is to be at least 60 % of the breadth b of the propeller post according to 2.1. 2.5 The wall thickness of the boss in propeller posts of welded construction according to 2.2 shall not be less than 0,9 the wall thickness of the boss according to D.2. The outer diameter of the sternframe boss, however,shall not belessthantheouterdiameterofthepropellerbossatitsforward edge. 3. Rudder post and rudder axle 3.1 The section modulus of the rudder post related to the longitudinal axis of the ship is not to be less than: Wx = CR @ R @ k @ 10-3 [cm3 ] R = unsupported span of the rudder post [m] Strength calculations for the rudder post, taking into account the flexibility of the sole piece, may be required where due to its low rigidity in y-direction the sole piece cannot be regarded as an efficient support for the rudder post and, therefore, additional bending stresses may arise at the upper point of constraint. The bending stress Fb is not to exceed 85 N/mm2 . 3.2 The diameter of a rudder axle of a balanced rudder is not to be less than : d = 4,2 [mm] R = length of rudder axle [m], see Fig. 13.4 b = [m] bl, b2 see Fig. 13.4. Regarding strength calculations for the rudder axle, respective remarks under 3.1 are to be observed. BKI - Rules for Hull - 2014
- 194. C Section 13 - Stem and Sternframe Structures13-4/8 Fig. 13.4 Stationary rudder axle 4. Sole piece 4.1 The section modulus of the sole piece related to the z-axis is not to be less than : Wz = [cm3 ] B1 = See A. For rudders with two supports the support force is approximately B1= CR/2, when the elasticity of the sole piece is ignored. x = distance of the respective cross section from the rudder axis [m] xmin = 0,5 @ R50 xmax = R50 R50 = see Fig. 13.5 and Section 14, C.3.2. Fig. 13.5 Length R50 of a sole piece 4.2 The section modulus Wz may be reduced by 15% where a rudder post according to 3.1 is fitted. 4.3 The section modulus related to the y-axis is not to be less than: - where no rudder post or rudder axle is fitted : Wy = - where a rudder post or rudder axle is fitted : Wy = BKI - Rules for Hull - 2014
- 195. Section 13 - Stem and Sternframe Structures C 13-5/8 4.4 The sectional area at the location x = R50 is not to be less than: As = [mm2 ]. 4.5 The equivalent stress taking into account bending and shear stresses at any location within the length R50 is not to exceed: Fv = = [N/mm2 ] Fb = [N/mm2 ] J = [N/mm2 ] 5. Rudder horn of semi spade rudders 5.1 The distribution of the bending moment, shear. force and torsional moment is to be determined according to the following formulae: – bending moment: Mb = Bl . z [Nm] Mbmax = Bl . d [Nm] – shear force: Q = Bl [N] – torsional moment: MT = Bl . e(z) [Nm] FordeterminingpreliminaryscantlingstheflexibilityoftherudderhornmaybeignoredandthesupportingforceBl becalculated according to the following formulae : Bl = CR [N] b, c, d, e(z) and z see Fig. 13.6 and 13.7 b result from the position of the centre of gravity of the rudder area. Fig. 13.6 - Arrangement of bearings of a semi spade rudder Fig. 13.7 - Loads on the rudder horn BKI - Rules for Hull - 2014
- 196. C Section 13 - Stem and Sternframe Structures13-6/8 5.2 The section modulus of the rudder horn in transverse direction related to the horizontal x-axis is at any location z not to be less than : Wx = [cm3 ] 5.3 At no cross section of the rudder horn the shear stress due to the shear force Q is to exceed the value: J = [N/mm2 ] The shear stress is to be determined by the following formulae : J = [N/mm2 ] Ah = effective shear area of the rudder horn in y-direction [mm2 ]. 5.4 The equivalent stress at any location (z) of the rudder horn shall not exceed the following value : Fv = # [N/mm2 ] Fb = [N/mm2 ] JT = [N/mm2 ] AT = sectional area [mm2 ] enclosed by the rudder horn at the location considered th = thickness of the rudder horn plating [mm]. 5.5 When determining the thickness of the rudder horn plating the provisions of 5.2 - 5.4 are to be complied with. The thickness is, however, not to be less than : tmin = 2,4 [mm] 5.6 The rudder horn plating is to be effectively connected to the aft ship structure, e.g. by connecting the plating to longitudinal girders, in order to achieve a proper transmission of forces, see Fig. 13.8. 5.7 Transverse webs of the rudder horn are to be led into the hull up to the next deck in a sufficient number and shall be of adequate thickness. 5.8 Strengthened plate floors are to be fitted in line with the transverse webs in order to achieve a sufficient connection with the hull. The thickness of these plate floors is to be increased by 50% above the Rule values as required by Section 8. 5.9 The centre line bulkhead (wash-plate) in the afterpeak is to be connected to the rudder horn. Fig. 13.8 - Rudder horn integration into the aft ship structure BKI - Rules for Hull - 2014
- 197. Section 13 - Stem and Sternframe Structures C, D, E 13-7/8 5.10 Where the transition between rudder horn and shell is curved, about 50 % of the required total section modulus of the rudder horn is to be formed by the webs in a Section A - A located in the centre of the transition zone, i.e. 0,7r above the beginning of the transition zone. See Fig. 13.9 Fig 13.9 Transition between rudder horn and shell D. Propeller Brackets 1. The strut axes should intersect in the axis of the propeller shaft a s far as practicable. The struts are to be extended through the shell plating and are to be attached in an efficient manner to the frames and plate floors respectively. The construction in way of the shell is to be carried out with special care. In case of welded connection, the struts are to haveaweldflangeorathickenedpartoraretobeconnectedwiththeshellplatinginanothersuitablemanner.For-strengthening of the shell in way of struts and shaft bossings, see Section 6, F. The requirements of Section 19, B.4.3 are to be observed. 2. The scantlings of solid struts are to be determined as outlined below depending on shaft diameter d : thickness : 0,44 d cross-sectional area in propeller bracket : 0,44 d2 length of boss : see Rules for Machinery Installations, Volume III, Section 4, D.5.2. wall thickness of boss : 0,25 d. 3. Propeller brackets and shaft bossings of welded construction are to have the same strength as solid ones according to 2. 4. For single strut propeller bracket a strength analysis according to E.1.2 and a vibration analysis according to E.2. are to be carried out. Due consideration is to be given to fatigue strength aspects. Single strut propeller bracket may also be determined as follows: W = 0.068 d3 I = 0.018 d4 where; W = section modulus of strut [mm3 ] I = moment inertia of strut [mm4 ] d = required shaft diameter [mm] Above formulae applies for bracket length, measured from the outside perimeter of the strut bracket or boss is not to exceed 10.6 d. Where this length is exceeded the scantling of the strut has to be increased. E. Elastic Stern Tube 1. Strength analysis When determining the scantlings of the stern tube in way of the connection with the hull, the following stresses are to be proved: BKI - Rules for Hull - 2014
- 198. E Section 13 - Stem and Sternframe Structures13-8/8 1.1 Static load: Bending stresses caused by static weight loads are not to exceed 0,35 ReH. 1.2 Dynamic load: The pulsating load due to loss of one propeller blade is to be determined assuming that the propeller revolutions are equal to 0,75 times the rated speed. The following permissible stresses are to be observed: Fperm= 0,40 ReH for ReH = 235 N/mm2 = 0,35 ReH for ReH = 355 N/mm2 . The aforementioned permissible stresses are approximate values. Deviations may be permitted in special cases taking into account fatigue strength aspects. 2. Vibration analysis The bending natural frequency at rated speed of the system comprising stern tube, propeller shaft and propeller is not to be less than 1,5 times the rated propeller revolutions. However, it is not to exceed 0,66 times the exciting frequency of the propeller (number of propeller blades x rated propeller revolutions) and is not to coincide with service conditions, including the damage condition (loss of one propeller blade). BKI - Rules for Hull - 2014
- 199. Section 14 - Rudder and Manoeuvring Arrangement A 14-1/21 Section 14 Rudder and Manoeuvring Arrangement A. General 1. Manoeuvring arrangement 1.1 Eachshipistobeprovidedwithamanoeuvringarrangementwhichwillguaranteesufficientmanoeuvringcapability. 1.2 Themanoeuvringarrangementincludesallpartsfromtherudderandsteeringgeartothesteeringpositionnecessary for steering the ship. 1.3 Rudder stock, rudder coupling, rudder bearings and the rudder body are dealt with in this Section. The steering gear is to comply with Rules for Machinery Installations, Volume III, Section 14. 1.4 The steering gear compartment shall be readily accessible and, as far as practicable, separated fromthe machinery space. (See also Chapter II-l, Reg. 29.13 of SOLAS 74.) Note Concerningtheuseofnon-magneticmaterialinthewheelhouseinwayofamagneticcompass,therequirementsoftheNational Administration concerned are to be observed. 1.5 For ice-strengthening see Section 15. 2. Structural details 2.1 Effectivemeansaretobeprovidedforsupportingtheweightoftherudderbodywithoutexcessivebearingpressure, e.g. by a rudder carrier attached to the upper part of the rudder stock. The hull structure in way of the rudder carrier is to be suitably strengthened. 2.2 Suitable arrangements are to be provided to prevent the rudder from lifting. Connections of rudder blade structure with solid parts in forged or cast steel, which are used as rudder stock housing, are to be suitably designed to avoid any excessive stress concentration at these areas. 2.3 The rudder stock is to be carried through the hull either enclosed in a watertight trunk, or glands are to be fitted above the deepest load waterline, to prevent water from entering the steering gear compartment and the lubricant from being washed away from the rudder carrier. If the top of the rudder trunk is below the deepest waterline two separate stuffing boxes are to be provided. Note The following measures are recommended for preventive measures to avoid or minimize rudder cavitation: Profile selection: – Use the appropriate profile shape and thickness. – Use profiles with a sufficiently small absolute value of pressure coefficient for moderate angles of attack (below 5°). Thepressuredistributionaroundtheprofileshouldbepossiblysmooth.Themaximumthicknessofsuchprofilesisusually located at more than 35 % behind the leading edge. – Use a large profile nose radius for rudders operating in propeller slips. – Computational Fluid Dynamic (CFD) analysis for rudder considering the propeller and ship wake can be used. Rudder sole cavitation : Round out the leading edge curve at rudder sole. Propeller hub cavitation : Fit a nacelle (body of revolution) to the rudder at the level of the propeller hub. This nacelle functions as an extension of BKI - Rules for Hull - 2013
- 200. A Section 14 - Rudder and Manoeuvring Arrangement14-2/21 the propeller hub. Cavitation at surface irregularities : – Grind and polish all welds. – Avoid changes of profile shape. Often rudders are built with local thickenings (bubbles) and dents to ease fitting of the rudder shaft. Maximum changes in profile shape should be kept to less than two percent of profile thickness. Gap cavitation : – Round out all edges of the part around the gap. – Gap size should be as small as possible. – Place gaps outside of the propeller slipstream. 3. Size of rudder area In order to achieve sufficient manoeuvring capability the size of the movable rudder area A is recommended to be not less than obtained from the following formula: A = c1 @ c2 @ c3 @ c4 @ [m2 ] c1 = factor for the ship type: = 1,0 in general = 0,9 for bulk carriers and tankers having a displacement of more than 50 000 ton = 1,7 for tugs and trawlers c2 = factor for the rudder type: = 1,0 in general = 0,9 for semi-spade rudders = 0,7 for high lift rudders c3 = factor for the rudder profile: = 1,0 for NACA-profiles and plate rudder = 0,8 for hollow profiles and mixed profiles c4 = factor for the rudder arrangement: = 1,0 for rudders in the propeller jet = 1,5 for rudders outside the propeller jet For semi-spade rudder 50% of the projected area of the rudder horn may be included into the rudder area A. Where more than one rudder is arranged the area of each rudder can be reduced by 20 %. Estimating the rudder area A, B.1. is to be observed. 4. Materials 4.1 For materials for rudder stock, pintles, coupling bolts etc. see Rules for Material Volume V. Special material requirements are to be observed for the ice Class Notations ES3 and ES4 as well as for the ice Class Notations PC7 - PC1. 4.2 In general materials having a minimum nominal upper yield point ReH of less than 200 N/mm2 and a minimum tensile strength of less than 400 N/mm2 or more than 900 N/mm2 shall not be used for rudder stocks, pintles, keys and bolts. The requirements of this Section are based on a material's minimum nominal upper yield point ReH of 235 N/mm2 . If material is used having a ReH differing from 235 N/mm2 , the material factor kr is to be determined as follows : BKI - Rules for Hull - 2013
- 201. Section 14 - Rudder and Manoeuvring Arrangement A 14-3/21 kr = for ReH > 235 [N/mm2 ] = for ReH 235 [N/mm2 ] ReH = minimum nominal upper yield point of material used [N/mm2 ]. ReH is not to be taken greater than 0,7. Rm or 450 N/mm2 , whichever is less. Rm = tensile strength of the material used. 4.3 Before significant reductions in rudder stock diameter due to the application of steels with ReH exceeding 235 N/mm2 are granted, BKI may require the evaluation of the elastic rudder stock deflections. Large deflections should be avoided in order to avoid excessive edge pressures in way of bearings. 4.4 The permissible stresses given in E.1. are applicable for normal strength hull structural steel. When higher tensile steels are used, higher values may be used which will be fixed in each individual case. 5. Definitions CR = rudder force [N] QR = rudder torque [Nm] A = total movable area of the rudder [m2 ], measured at the mid-plane of the rudder For nozzle rudders, A is not to be taken less than 1,35 times the projected area of the nozzle. At = A + area of a rudder horn, if any, [m2 ] Af = portion of rudder area located ahead of the rudder stock axis [m2 ] b = mean height of rudder area [m] c = mean breadth of rudder area [m] (see Fig. 14.1a) Fig. 14.1a Rudder area geometry 7 = aspect ratio of rudder area At = v0 = ahead speed of ship [kn] as defined in Section.1, H.5.; if this speed is less than 10 kn, v0 is to be taken as [kn] va = astern speed of ship [kn]; if the astern speed va < 0,4 @ v0 or 6 kn, whichever is less, determination of rudder force and torque for astern condition is not required. For greater astern speeds special evaluation of rudder force and torque as a function of the rudder angle may be required. If no limitations for the rudder angle at BKI - Rules for Hull - 2013
- 202. A,B Section 14 - Rudder and Manoeuvring Arrangement14-4/21 astern condition is stipulated, the factor 62 is not to be taken less than given in Table 14.1forasterncondition. k = material factor according to Section 2, B.2. For ships strengthened for navigation in ice, Section 15, B.9 and D.3.7 have to be observed. B. Rudder Force and Torque 1. Rudder force and torque for normal rudders 1.1 The rudder force is to be determined according to the following formula: CR = 132 @ A @ v2 @ 61 @ 62 @ 63 @ 6t [N] v = v0 for ahead condition = va for astern condition 61 = coefficient, depending on the aspect ratio 7 = (7 + 2)/3, where 7 need not be taken greater than 2 62 = coefficient, depending on the type of the rudder and the rudder profile according to Table 14.1. 63 = coefficient, depending on the location of the rudder = 0,8 for rudders outside the propeller jet = 1,0 elsewhere, including also rudders within the propeller jet = 1,15 for rudders aft of the propeller nozzle 6t = coefficient depending on the thrust coefficient CTh = 1,0 normally In special cases for thrust coefficients CTh > 1,0 determination of 6t according to the following formula may be required: 6t = 1.2 The rudder torque is to be determined by the following formula: QR = CR @ r [Nm] r = c (" n kb) [m] " = 0,33 for ahead condition = 0,66 for astern condition (general) = 0,75 for astern condition (hollow profiles) For parts of a rudder behind a fixed structure such as a rudder horn: " = 0,25 for ahead condition = 0,55 for astern condition. For high lift rudders " is to be specially considered. If not known, " = 0,4 may be used for the ahead condition. kb = balance factor as follows: = = 0,08 for unbalanced rudders rmin = 0,1 @ c [m] for ahead condition. 1.3 Effects of the provided type of rudder / profile on choice and operation of the steering gear are to be observed. BKI - Rules for Hull - 2013
- 203. Section 14 - Rudder and Manoeuvring Arrangement B 14-5/21 2. Rudder force and torque for rudder blades with cut-outs (semi-spade rudders) 2.1 The total rudder force CR is to be calculated according to 1.1. The pressure distribution over the rudder area, upon which the determination of rudder torque and rudder blade strength is to be based, is to be derived as follows : The rudder area may be divided into two rectangular or trapezoidal parts with areas A1 and A2 (see Fig. 14.2). Table 14.1 - Coefficient 62 Profile Type 62 Ahead Condition Astern Condition for Ordinary Rudders 1 Single plate 1.0 1.0 2 NACA-OO Göttingen 1.1 0.80 3 Flat Side 1.1 0.90 4 Mixed (e.g., HSVA) 1.21 0.90 5 Hollow 1.35 0.90 for High-Lift/Performance Rudders 6 Fish tail (e.g., Schilling high-lift rudder) 1.4 0.8 7 Flap rudder 1.7 1.3 8 Rudder with steering nozzle 1.9 1.5 The resulting force of each part may be taken as: CR1 = CR [N] BKI - Rules for Hull - 2013
- 204. B, C Section 14 - Rudder and Manoeuvring Arrangement14-6/21 CR2 = CR [N] 2.2 The resulting torque of each part may be taken as: QR1 = CR1 @ r1 [Nm] QR2 = CR2 @ r2 [Nm] The levers r1 and r2 are to be determined as follows : r1 = c1 (" n kbl) [m] r2 = c2 (" n kb2) [m] kb1 = kb2 = A1f, A2f see Fig. 14.2 c1 = c2 = b1, b2 = mean heights of the partial rudder areas A1 and A2 (see Fig. 14.2). Fig. 14.2 Partial area A1 and A2 2.3 The total rudder torque is to be determined according to the following formulae: QR = QR1 + QR2 [Nm] or QRmin = CR @ r1,2min [Nm] r1,2min = ( c1 @ A1 + c2 @ A2 ) [m] for ahead condition The greater value is to be taken. C. Scantlings of the Rudder Stock 1. Rudder stock diameter 1.1 The diameter of the rudder stock for transmitting the torsional moment is not to be less than : Dt = 4,2 [mm] BKI - Rules for Hull - 2013
- 205. Section 14 - Rudder and Manoeuvring Arrangement C 14-7/21 QR see B. 1.2 and B. 2.2 - 2.3. The related torsional stress is: Jt = [N/mm2 ] kr see A.4.2. 1.2 The steering gear is to be determined according to Rules for Machinery Installations, Volume III, Section 14 for theruddertorque QR as required in B.1.2, B.2.2 or B.2.3 and under considerationofthefrictionallossesattherudderbearings. 1.3 In case of mechanical steering gear the diameter of the rudder stock in its upper part which is only intended for transmission of the torsional moment fromthe auxiliary steering gear may be 0,9 Dt. The length of the edge of the quadrangle for the auxiliary tiller shall not be less than 0,77 Dt and the height not less than 0,8 Dt. 1.4 The rudder stock is to be secured against axial sliding. The degree of the permissible axial clearance depends on the construction of the steering engine and on the bearing. 2. Strengthening of rudder stock If the rudder is so arranged that additional bending stresses occur in the rudder stock, the stock diameter has to be suitably increased. The increased diameter is, where applicable, decisive for the scantlings of the coupling. For the increased rudder stock diameter the equivalent stress of bending and torsion is not to exceed the following value: Fv = = [N/mm2 ] Bending stress: Fb = [N/mm2 ] Mb = bending moment at the neck bearing [Nm] Torsional stress: J = [N/mm2 ] D1 = increased rudder stock diameter [mm] The increased rudder stock diameter may be determined by the following formula: D1 = Dt [mm] QR see B.1.2 and B.2.2 - 2.3 Dt see 1.1. Note Where a double-piston steering gear is fitted, additional bending moments may be transmitted from the steering gear into the rudder stock. These additional bending moments are to be taken into account for determining the rudder stock diameter. 3. Analysis 3.1 General The evaluation of bending moments, shear forces and support forces for the system rudder - rudder stock may be carried out for some basic rudder types as shown in Figs. 14.3 - 14.5 as outlined in 3.2. - 3.3. 3.2 Data for the analysis R10 n R40 = lengths of the individual girders of the system [m] I10 n I40 = moments of inertia of these girders [cm4 ] BKI - Rules for Hull - 2013
- 206. C Section 14 - Rudder and Manoeuvring Arrangement14-8/21 For rudders supported by a sole piece the length R20 is the distance between lower edge of rudder body and centre of sole piece, and I20 is the moment of inertia of the pintle in the sole piece. Load on rudder body (general): pR = [kN/m] Load on semi-spade rudders: pR10 = [kN/m] pR20 = [kN/m] CR, CR1, CR2 see B.1. and B.2. Z = spring constant of support in the sole piece or rudder horn respectively for the support in the sole piece (Fig. 14.3) : Z = [kN/m] for the support in the rudder horn (Fig. 14.4) : Z = [kN/m] fb = unit displacement of rudder horn [m] due to a unit force of 1 kN acting in the centre of support fb = 0,21 [m/kN] (guidance value for steel) In = moment of inertia of rudder horn around the x-axis at d/2 [cm4 ] (see also Fig. 14.4) ft = unit displacement due to torsional moment of the amount 1 @ e [kNm] = = [m/kN] for steel G = modulus of rigity = 7,92 @ 107 [kN/m2 ] for steel Jt = torsional moment of inertia [m4 ] FT = mean sectional area of rudder horn [m2 ] ui = breadth [mm] of the individual plates forming the mean horn sectional area ti = plate thickness within the individual breadth ui [mm] e, d = distances [m] according to Fig. 14.4. BKI - Rules for Hull - 2013
- 207. Section 14 - Rudder and Manoeuvring Arrangement C 14-9/21 Fig. 14.3 Rudder supported by sole piece Fig. 14.4 Semi-spade rudder BKI - Rules for Hull - 2013
- 208. C Section 14 - Rudder and Manoeuvring Arrangement14-10/21 Fig. 14.5 Spade rudder Fig. 14.6 - Spade rudders with rudder trunks inside the rudder body 3.3 Moments and forces to be evaluated 3.3.1 The bending moment MR and the shear force Ql in the rudder body, the bending moment Mb in the neck bearing and the support forces Bl, B2, B3 are to be evaluated. The so evaluated moments and forces are to be used for the stress analyses required by 2. and E.1. of this Section and by Section 13, C.4. and C.5. 3.3.2. For spade rudders the moments and forces may be determined by the following formulae: Mb = CR [Nm] B3 = [N] B2 = CR + B3 [N] BKI - Rules for Hull - 2013
- 209. Section 14 - Rudder and Manoeuvring Arrangement C 14-11/21 3.3.3 For spade rudders with rudder trunks (seeFig.14.6)themomentsandforcesmaybedeterminedbythe following formulae: CR1 = rudder force over the partial rudder area A1 according to B.2.1 [N] CR2 = rudder force over the partial rudder area A2 according to B.2.1 [N] MCR1 = [Nm] MCR2 = [Nm] MR = Max (MCR1, MCR2) [Nm] Mb = MCR2 - MCR1 [Nm] B3 = [N] B2 = CR + B3 [N] 4. Rudder trunk 4.1 In case where the rudder stock is fitted with a rudder trunk welded in such a way the rudder trunk is loaded by thepressureinducedontherudderblade,asgiveninB.1.1,thebendingstressintheruddertrunk,inN/mm2 ,istobeincompliance with the following formula : F < 80 / k where the material factor k for the rudder trunk is not to be taken less than 0,7. For the calculation of the bending stress, the span to be considered is the distance between the mid-height of the lower rudder stock bearing and the point where the trunk is clamped into the shell or the bottom of the skeg. 4.2 The weld at the connection between the rudder trunk and the shellorthebottomoftheskegistobefullpenetration. The fillet shoulder radius r, in mm, is to be as large as practicable and to comply with the following formulae: r = 60 when F $ 40 / k [N/mm2 ] r = 0,1 D1 when F < 40 / k [N/mm2 ] without being less than 30, where D1 is defined in 2.1. Note The radius may be obtained by grinding. If disk grinding is carried out, score marks are to be avoided in the direction of the weld. The radius is to be checked with a template for accuracy. Four profiles at least are to be checked. A report is to be submitted to the Surveyor. Before welding is started, a detailedweldingprocedurespecificationistobesubmittedto BKIcovering the weld preparation, weldingpositions,weldingparameters,weldingconsumables,preheating,postweldheattreatmentandinspectionprocedures. This welding procedure is to be supported by approval tests in accordance with the applicable requirements of materials and welding sections of the rules. The manufacturer is to maintain records of welding, subsequentheat treatment and inspections traceable to the welds. These records are to be submitted to the Surveyor. Non destructive tests are to be conducted at least 24 hours after completion of the welding. The welds are to be 100 % magnetic particle tested and 100 % ultrasonic tested. BKI - Rules for Hull - 2013
- 210. D Section 14 - Rudder and Manoeuvring Arrangement14-12/21 D. Rudder Couplings 1. General 1.1 The couplings are to be designed in such a way as to enable them to transmit the full torque of the rudder stock. 1.2 The distance of bolt axis fromthe edges of the flange is notto be less than 1,2 the diameter of the bolt. In horizontal couplings, at least 2 bolts are to be arranged forward of the stock axis. 1.3 The coupling bolts are to be fitted bolts. The bolts and nuts are to be effectively secured against loosening, e.g. according to recognized standards. 1.4 For spade rudders horizontal couplings according to 2. are permissible only where the required thickness of the coupling flanges tf is less than 50 mm, otherwise cone couplings according to 4. are to be applied. For spade rudders of the high lift type, only cone couplings according to 4. are permitted. 2. Horizontal couplings 2.1 The diameter of coupling bolts is not to be less than : db = 0,62 [mm] D = rudder stock diameter according to C. [mm] n = total number of bolts, which is not to be less than 6 e = mean distance of the bolt axes from the centre of bolt system [mm] kr = material factor for the rudder stock as given in A.4.2 kb = material factor for the bolts analogue to A.4.2. 2.2 The thickness of the coupling flanges is not to be less than determined by the following formulae: tf = 0,62 [mm] tfmin = 0,9 @ db kf = material factor for the coupling flanges analogue to A.4.2. The thickness of the coupling flanges clear of the bolt holes is not to be less than 0,65 @ tf. The width of material outside the bolt holes is not to be less than 0,67 @ db. 2.3 ThecouplingflangesaretobeequippedwithafittedkeyaccordingtoDIN6885orequivalentstandardsforrelieving the bolts. The fitted key may be dispensed with if the diameter of the bolts is increased by 10%. 2.4 Horizontal coupling flanges should either be forged togetherwith the rudder stock or be weldedtotherudderstock as outlined in Section 19, B.4.4.3. 2.5 For the connection of the coupling flanges with the rudder body see also Section 19, B.4.4. 3. Vertical couplings 3.1 The diameter of the coupling bolts is not to be less than : db = [mm] D, kb, kr, n see 2.1, where n is not to be less than 8. BKI - Rules for Hull - 2013
- 211. Section 14 - Rudder and Manoeuvring Arrangement D 14-13/21 3.2 The first moment of area of the bolts about the centre of the coupling is not to be less than : S = 0,00043 D3 [cm3 ]. 3.3 The thickness of the coupling flanges is not to be less than : tf = db [mm] The width of material outside the bolt holes is not to be less than 0,67 @ db. 4. Cone couplings 4.1 Cone couplings with key 4.1.1 Cone couplings should have a taper c on diameter of 1: 8 - 1:12. c = according Fig. 14.7. The cone shapes should fit very exact. The nut is to be carefully secured, e.g. by securing plate as shown in Fig. 14.7. Fig. 14.7 - Cone coupling with key and securing plate 4.1.2The coupling length R shall, in general. not be less than 1,5 @ d0. 4.1.3For couplings between stock and rudder a key is to be provided, the shear area of which is not to be less than: as = [cm2 ] QF = design yield moment of rudder stock [Nm] according to F. dk = diameter of the conical part of the rudder stock [mm] at the key ReHl = minimum nominal upper yield point of the key material [N/mm2 ] 4.1.4The effective surface area of the key (without rounded edges) between key and rudder stock or cone coupling, is not to be less than: ak = [cm2 ] ReH2 = minimum nominal upper yield point of the key, stock or coupling material [N/mm2 ], whichever is less. 4.1.5The dimensions of the slugging nut are to be as follows, see Fig. 14.7: – height: BKI - Rules for Hull - 2013
- 212. D Section 14 - Rudder and Manoeuvring Arrangement14-14/21 hn = 0,6 @ dg – outer diameter (the greater value to be taken): dn = 1,2 @ du or dn = 1,5 @ dg – external thread diameter: dg = 0,65 @ d0 4.1.6It is to be proved that 50% of the design yield moment will be solely transmitted by friction in the cone couplings. This can be done by calculating the required push-up pressure and push-up length according to 4.2.3 for a torsional moment Q'F = 0,5 @ QF 4.2 Cone couplings with special arrangements for mounting and dismounting the couplings 4.2.1Wherethestockdiameterexceeds200mmthepressfitisrecommendedtobeeffectedbyahydraulicpressureconnection. In such cases the cone should be more slender, c . 1:12 to . 1 : 20. 4.2.2In case of hydraulic pressure connections the nut is to be effectively secured against the rudder stock or the pintle. A securing plate for securing the nut against the rudder body is not to be provided, see Fig. 14.8. Fig. 14.8 - Cone coupling without key and with securing flat bar Note A securing flat bar will be regarded as an effective securing device of the nut, if its shear area is not less than: As = [ mm2 ] Ps = shear force as follows = [N] Pe = push-up force according to 4.2.3.2 [N] µ1 = frictional coefficient between nut and rudder body, normally µ1 = 0,3 d1 = mean diameter of the frictional area between nut and rudder body, see Fig. 14.8 dg = thread diameter of the nut ReH = yield point [N/mm²] of the securing flat bar material. 4.2.3For the safe transmission of the torsional moment by the coupling between rudder stock and rudder body the push-up length and the push-up pressure are to be determined by the following formulae. 4.2.3.1 Push-up pressure The push-up pressure is not to be less than the greater of the two following values : BKI - Rules for Hull - 2013
- 213. Section 14 - Rudder and Manoeuvring Arrangement D 14-15/21 preq1 = [N/mm2 ] preq2 = [N/mm2 ] QF = design yield moment of rudder stock according to F. [Nm] dm = mean cone diameter [mm] R = cone length [mm] :0 . 0,15 (frictional coefficient) Mb = bending moment in the cone coupling (e.g. in case of spade rudders) [Nm]. It has to be proved that the push-up pressure does not exceed the permissible surface pressure in the cone. The permissible surface pressure is to be determined by the following formula : pperm = [N/mm2 ] ReH = yield point [N/mm2 ] of the material of the gudgeon " = dm /da (see Fig 14.7) The outer diameter of the gudgeon shall not be less than: da = 1,5 @ dm [mm] 4.2.3.2 Push-up length The push-up length is not to be less than: )R1 = [mm] Rtm = mean roughness [mm] • 0,01 mm c = taper on diameter according to 4.2.1 E = Young's modulus (2,06 @ 105 N/mm2 ) A guidance figure for the minimum push-up length is : )Rmin= [mm] The push-up length is, however, not to be taken greater than : )R2 = [mm] Note In case of hydraulic pressure connections the required push-up force Pe for the cone may be determined by the following formula : Pe = [N] The value 0,02 in above formula is a reference value for the friction coefficient using oil pressure. It varies and depends on the mechanical treatment and roughness of the details to be fixed. Whereduetothefittingprocedureapartialpush-upeffectcaused bythe rudder weightis given,thismaybetakenintoaccount when fixing the required push-up length, subject to approval by BKI. BKI - Rules for Hull - 2013
- 214. D, E Section 14 - Rudder and Manoeuvring Arrangement14-16/21 4.2.4The required push-up pressure for pintle bearings is to be determined by the following formula : preq = 0,4 [N/mm2 ] Bl = supporting force in the pintle bearing [N], see also Fig. 14.4 dm, R = see 4.2.3 d0 = pintle diameter [mm] according to Fig. 14.7. E. Rudder Body, Rudder Bearings 1. Strength of rudder body 1.1 The rudder body is to be stiffened by horizontal and vertical webs in such a manner that the rudder body will be effective as a beam. The rudder should be additionally stiffened at the aft edge. 1.2 The strength of the rudder body is to be proved by direct calculation according to C.3. 1.3 For rudder bodies without cut-outs the permissible stress are limited to : bending stress due to MR: Fb = 1l0 [N/mm2 ] shear stress due to Ql: J = 50 [N/mm2 ] equivalent stress due to bending and shear: Fv = = 120 [N/mm2 ] MR, Q1 see C.3.3.and Fig.14.3 and 14.4. In case of openings in the rudder plating for access to cone coupling or pintle nut the permissible stresses according to 1.4 apply.Smallerpermissiblestressvaluesmayberequiredifthecornerradiiarelessthan 0,15@ ho, where ho = heightofopening. 1.4 In rudder bodies with cut-outs (semi-spade rudders) the following stress values are not to be exceeded : bending stress due to MR : Fb = 90 [N/mm2 ] shear stress due to Ql : J = 50 [N/mm2 ] torsional stress due to Mt : Jt = 50 [N/mm2 ] equivalent stress due to bending and shear and equivalent stress due to bending and torsion: Fv1 = = 120 [N/mm2 ] Fv2 = = 100 [N/mm2 ] MR = CR2 @ fl + B1 [Nm] Q1 = CR2 [N] f1, f2 see Fig. 14.9. The torsional stress may be calculated in a simplified manner as follows : Jt = [N/mm2 ] BKI - Rules for Hull - 2013
- 215. Section 14 - Rudder and Manoeuvring Arrangement E 14-17/21 Mt = CR2 @ e [Nm] CR2 = partial rudder force [N] of the partial rudder area A2 below the cross section under consideration e = lever for torsional moment [m] (horizontal distance between the center of pressure of area A2 and the centre line a-a of the effective cross sectional area under consideration, see Fig. 14.9. The center of pressure is to be assumed at 0,33 @ c2 aft of the forward edge of area A2, where c2 = mean breadth of area A2) h, R, t [cm], see Fig. 14.9. Fig. 14.9 Geometry of semi-spade rudder The distance R between the vertical webs should not exceed 1,2 @ h. The radii in the rudder plating are not to be less than 4 - 5 times the plate thickness, but in no case less than 50 mm. Note It is recommended to keep the natural frequency of the fully immersed rudder and of local structural components at least 10% above the exciting frequency of the propeller (number of revolutions x number of blades) or if relevant, above higher order. 2. Rudder plating 2.1 Double plate rudders 2.1.1The thickness of the rudder plating is to be determined according to the following formula: t = [mm] PR = 10 @ T + [kN/m2 ] a = the smaller unsupported width of a plate panel [m]. The influence of the aspect ratio of the plate panels may be taken into account as given in Section 3, A.3. The thickness shall, however, not be less than the thickness tmin according to Section 6, B.3.1. To avoid resonant vibration of single plate fields the frequency criterion as defined in Section 12, A.8.3 (" < 60°) for shell structures applies analogously. Regarding dimensions and welding Section 19, B.4.4.1 has to be observed in addition. 2.1.2For connecting the side plating of the rudder to the webs tenon welding is not to be used. Where application of fillet welding is not practicable, the side plating is to be connected by means of slot welding to flat bars which are welded to the webs. 2.1.3The thickness of the webs is not to be less than 70% of the thickness of the rudder plating according to 2.1.1, but not less than: tmin = 8 [mm] Webs exposed to seawater must be dimensioned according to 2.1.1. BKI - Rules for Hull - 2013
- 216. E Section 14 - Rudder and Manoeuvring Arrangement14-18/21 2.2 Single plate rudders 2.2.1 Main piece diameter The main piece diameter is calculated according to C.1 and C.2 respectively. For spade rudders the lower third may taper down to 0.75 times stock diameter. 2.2.2Blade thickness 2.2.2.1 The blade thickness is not to be less than: tb = [mm] a = spacing of stiffening arms [m], not to exceed 1 m; v0 = ahead speed of ship [kn] 2.2.2.2 After edge of rudder plating to be rounded. 2.2.3Arms The thickness of the arms “ t a” is not to be less than the blade thickness according to 2.2.2. The section modulus is to be determined as follow: Wa = [cm3 ] c1 = horizontal distance from the aft edge of the rudder to the centreline of the rudder stock [m]. 3. Transmitting of the rudder torque 3.1 For transmitting the rudder torque, the rudder plating according to 2.1.1 and 2.2.2.1 is to be increased by 25% in way of the coupling. A sufficient number of vertical webs is to be fitted in way of the coupling. 3.2 If the torque is transmitted by a prolonged shaft extended into the rudder, the latter shall have the diameter Dt or D1, whichever is greater, at the upper 10% of the intersection length. Downwards it may be tapered to 0,6 Dt, in spade rudders to 0,4 times the strengthened diameter, if sufficient support is provided for. 4. Rudder bearings 4.1 In way of bearings liners and bushes are to be fitted. Their minimum thickness is tmin = 8 mm for metallic materials and synthetic material = 22 mm for lignum material Where in case of small ships bushes are not fitted, the rudder stock is to be suitably increased in diameter in way of bearings enabling the stock to be re-machined later. 4.2 An adequate lubrication is to be provided. 4.3 The bearing forces result from the direct calculation mentioned in C.3. As a first approximation the bearing force may be determined without taking account of the elastic supports. This can be done as follows: – normal rudder with two supports: The rudder force CR is to be distributed to the supports according to their vertical distances from the centre of gravity of the rudder area. – semi-spade rudders: S support force in the rudder horn: B1 = CR @ [N] S support force in the neck bearing: B2 = CR - Bl [N] BKI - Rules for Hull - 2013
- 217. Section 14 - Rudder and Manoeuvring Arrangement E 14-19/21 For b and c see Section 13, Fig. 13.6. 4.4 The projected bearing surface Ab (bearing height x external diameter of liner) is not to be less than Ab = [mm2 ] B = support force [N] q = permissible surface pressure according to Table 14.2 Table 14.2 - Permissible surface pressure q Bearing material q [N/mm2 ] lignum vitae 2,5 white metal, oil lubricated 4,5 synthetic material1) 5,5 steel2) , bronze and hot-pressed bronze-graphite materials 7,0 1) Synthetic materials to be of approved type. Surfacepressuresexceeding5,5N/mm²maybeacceptedinaccordancewithbearing manufacturer's specification and tests, but in no case more than 10 N/mm². 2) Stainlessandwearresistantsteelinanapprovedcombinationwithstockliner.Higher surface pressures than7 N/mm² may be accepted if verified by tests. 4.5 Stainlessandwearresistantsteels,bronzeandhot-pressedbronze-graphitematerialshaveaconsiderabledifference in potential to non-alloyed steel. Respective preventive measures are required. 4.6 The bearingheightshallbeequalto the bearing diameter, however, is not to exceed 1,2 times the bearing diameter. Where the bearing depth is less than the bearing diameter, higher specific surface pressures may be allowed. 4.7 The wallthickness ofpintle bearingsinsolepieceandrudderhornshallbeapproximately¼of the pintle diameter. 5. Pintles 5.1 Pintles are to have scantlings complying with the conditions given in 4.4 and 4.6. The pintle diameter is not to be less than: d = 0,35 [mm] Bl = support force [N] kr = see A.4.2. 5.2 The thickness of any liner or bush shall not be less than: t = 0,01 [mm] or the values in 4.1 respectively. 5.3 Where pintles are of conical shape, they are to comply with the following: taper on diameter 1: 8 to 1: 12 if keyed by slugging nut, taper on diameter 1: 12 to 1: 20 if mounted with oil injection and hydraulic nut. 5.4 The pintles are to be arranged in such a manner as to prevent unintentional loosening and falling out. For nuts and threads the requirements of D.4.1.5 and 4.2.2 apply accordingly. 6. Guidance values for bearing clearances 6.1 For metallic bearing material the bearing clearance shall generally not be less than: BKI - Rules for Hull - 2013
- 218. E, F, G, H Section 14 - Rudder and Manoeuvring Arrangement14-20/21 [mm] db = inner diameter of bush. 6.2 If non-metallic bearing material is applied, the bearing clearance is to be specially determined considering the material's swelling and thermal expansion properties and to be in accordance with maker recommendation. 6.3 The clearance is not to be taken less than 1,5 mmon diameter. In case of self lubricating bushes going down below this value can be agreed to on the basis of the manufacturer's specification. F. Design Yield Moment of Rudder Stock The design yield moment of the rudder stock is to be determined by the following formula: QF = 0,02664 [Nm] Dt = stock diameter [mm] according to C.1. Where the actual diameter Dta is greater than the calculated diameter Dt, the diameter Dta is to be used. However, Dta need not be taken greater than 1,145 . Dt. G. Stopper, Locking Device 1. Stopper The motions of quadrants or tillers are to be limited on either side by stoppers. The stoppers and their foundations connected to the ship's hull are to be of strong construction so that the yield point of the applied materials is not exceeded at the design yield moment of the rudder stock. 2. Locking device Each steering gear is to be provided with a locking device in order to keep the rudder fixed at any position. This device as well as the foundation in the ship's hull are to be of strong construction so that the yield point of the applied materials is not exceeded at the design yield moment of the rudder stock as specified in F. Where the ship's speed exceeds 12 kn, the design yield moment need only be calculated for a stock diameter based on a speed v0 = 12 [kn]. 3. Regarding stopper and locking device see also Rules for Machinery Installations, Volume III, Section.14. H. Propeller Nozzles 1. General 1.1 The following requirements are applicable to propeller nozzles having an inner diameter of up to 5 m. Nozzles with larger diameters will be specially considered. 1.2 Special attention is to be given to the support of fixed nozzles at the hull structure. 2. Design pressure The design pressure for propeller nozzles is to be determined by the following formula : pd = [kN/m2 ] pdo = g [kN/m2 ] N = maximum shaft power [kW] BKI - Rules for Hull - 2013
- 219. Section 14 - Rudder and Manoeuvring Arrangement H 14-21/21 Ap = propeller disc area [m2 ] = D = propeller diameter [m] g = factor according to the following formula: g = 0,21 n 2 @ 10-4 gmin = 0,10 c = 1,0 in zone 2 (propeller zone), = 0,5 in zones 1 and 3 = 0,35 in zone 4. see Fig. 14.10 Fig. 14.10 Zone 1 to 4 of propeller nozzle 3. Plate thickness 3.1 The thickness of the nozzle shell plating is not to be less than: t = 5 @ + tK [mm] tmin = 7,5 [mm] a = spacing of ring stiffeners [m]. 3.2 The web thickness of the internal stiffening rings shall not be less than the nozzle plating for zone 3, however, in no case be less than 7,5 mm. 4. Section modulus The section modulus of the cross section shown in Fig. 14.10 around its neutral axis is not to be less than: W = n @ d2 @ b @ v0 2 [cm3 ] d = inner diameter of nozzle [m] b = length of nozzle [m] n = 1,0 for rudder nozzles = 0,7 for fixed nozzles. 5. Welding Theinnerandouternozzleshellplatingistobeweldedtotheinternalstiffeningringsasfaraspracticablebydoublecontinuous welds. Plug welding is only permissible for the outer nozzle plating. BKI - Rules for Hull - 2013
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- 221. Section 15 - Strengthening for Navigation in Ice A 15-1/17 Section 15 Strengthening for Navigation in Ice A. General 1. Ice class notations 1.1 The strengthenings for the various ice class notations are recommended for navigation under the following ice conditions: Ice class notation Ice conditions ES Drift ice in mouths of rivers, and coastal regions ES1 ES2 ES3 ES4 Ice conditions as in the Northern Baltic1 1 See paragraph 1.1 of the Finnish Swedish Ice Class Rules, as ammended. 1.2 Ships the ice-strengthening of which complies with the requirements of B. will have the notation ES1, ES2, ES3 or ES4 affixed to their Character of Classification. 1.3 The requirements for the ice class notations ES1 ― ES4 embody all necessary conditions to be complied with for assignment of the ice classes IC - IA "Super" according to the "Finnish-Swedish Ice Class Rules 1985, as amended". The ice class notations mentioned under 1.1 are equivalent to the Finnish-Swedish Ice Class in the following way: Ice class notation ES1 corresponds to ice class IC. Ice class notation ES2 corresponds to ice class IB. Ice class notation ES3 corresponds to ice class IA. Ice class notation ES4 corresponds to ice class IA "Super". Note The Finnish-Swedish Ice Class Rules set the minimum requirements for engine power and ice strengthening for ships navigating the Baltic Sea with the assistance of icebreakers when necessary. Special consideration should be given to ships designed for independent navigation and/or for ships designed for navigation in areas other than the Baltic Sea (e.g. see paragraph 4.1.4 of Guidelines for the Application of the Finnish-Swedish Ice Class Rules). The Swedish Maritime Administration has provided ice class notations IBV and ICV for vessels navigating Lake Vänern (“Regulations and General Advice of the Swedish Maritime Administration on Swedish Ice Class for Traffic on Lake Vänern”, SJÖFS 2003:16). The requirements for ice class notations IBV and ICV are the same as those for ice class notations ES2 and ES1, respectively, except for the calculation of minimum propulsion machinery output, see A.3. When calculating the resistance of the vessel, the thickness of brash ice in mid channel, HM, is to be taken as 0,65 m for ice class notation IBV and 0,50 m for ice class notation ICV. For vessels complying with the requirements for ice class notations IBV and ICV, a corresponding entry will be made in the Annex to the Class Certificate. 1.4 The ice class notations ES1- ES4 can only be assigned to self-propelled ships when in addition to the requirements of this Section also the relevant Machinery Construction Rules according to Volume III, Section 13 are complied with. For example, the Character of Classification then reads: A 100 ES1; + SM ES1. Where the hull only is strengthened for a higher ice class notation, a corresponding entry will be made in the Annex to the Class Certificate. 1.5 Ships the ice strengthening of which complies with the requirements of C. will have the notation ES affixed to their Character of Classification. BKI - Rules Volume II - 2014
- 222. A Section 15 - Strengthening for Navigation in Ice15-2/17 Upon request, the Notation ES may be assigned independently for hull or machinery. 1.6 Ships which beyond the requirements for the ice Class Notations ES, ES1 to ES4 or PC7 to PC1 have been specially designed, dimensioned and/or equippedforicebreakingwillhaveaffixedthenotationICEBREAKER in addition. Dimensioning of the structure with regard to the foreseen area of operation has to be harmonized with BKI. 1.7 Ships intended for navigation in arctic waters may have the ice Class Notations PC7 - PC1 affixed to their Character of Classification if the requirements given in Guidelines for the Construction of Polar Class Ships are complied with. 1.8 If the scantlings required by this Section are less than those required for ships without ice strengthening, the scantlings required by the other Sections of these Rules are to be maintained. 2. Ice class draught for Ships with Notations ES1-ES4 2.1 The upper ice waterline (UIWL) is to be the highest waterline at which the ship is intended to operate in ice. The lower ice waterline (LIWL) is to be the lowest waterline at which the ship is intended to operate in ice. Both the UIWL and LIWL may be broken lines. 2.2 The maximum and minimum ice class draughts at the forward perpendicular, amidships and at the aft perpendicular are to be determined in accordance with the upper/lower ice waterlines and are to be stated in the drawings submitted for approval. The maximum ice class draught at the forward perpendicular is not to be less than the maximum draught at amidships. The ice class draughts, the minimum propulsion machinery output, P, according to 3., as well as the corresponding ice class, will be stated in the Annex to the Class Certificate. If the summer load line in fresh water is located at a higher level than the UIWL, the ship's sides are to be provided with a warning triangle and with an ice class draught mark at the maximum permissible ice class draught amidships (see Annex B). 2.3 The draught and trim, limited by the UIWL,shall not be exceeded when the ship is navigating in ice. The salinity of the sea water along the intended route is to be taken into account when loading the ship. The ship is always to be loaded down at least to the LIWL when navigating in ice. The LIWL is to be agreed upon with the owners. For ships with the ice class notations E1 – E4, any ballast tank adjacent to the side shell and situated above the LIWL, and needed to load the ship down to this waterline, is to be equipped with devices to prevent the water from freezing. In determining the LIWL, regard is to be paid to the need for ensuring a reasonable degree of ice-going capability in ballast. The propeller is to be fully submerged, entirely below the ice, if possible. 2.4 For ships with the ice class notations ES1 - ES4 the minimum draught at the forward perpendicular shall not be less than the smaller of the following values : Tmin = h0 (2 + 2,5 @ 10-4 @ D) [m] or Tmin = 4 @ h0 [m] D = displacement of the ship [t] on the maximum ice class draught according to 2.1 h0 = design ice thickness according to B.2.1. 3. Propulsion machinery output for ships with Notations ES1-ES4 3.1 The propulsion machinery output P in the context of this Section, is the total maximum output the propulsion machinery can continuously deliver to the propeller(s). If the output of the machinery is restricted by technical means or by any regulations applicable to the ship, P is to be taken as the restricted output. 3.2 For ships with the ice class notation ES1 or ES2, the keels of which were laid or which are in a similar stage of construction before September 1st , 2003, the propulsion machinery output is not to be less than: P = f1 @ f2 @ f3 (f4 @ D + P0) [kW] Pmin = 740 kW f1 = 1,0 for a fixed pitch propeller BKI - Rules Volume II - 2014
- 223. Section 15 - Strengthening for Navigation in Ice A 15-3/17 = 0,9 for a controllable pitch propeller f2 = + 0,675, but not more than 1,1 = 1,1 for a bulbous bow f1 @ f2 > 0,85 n1 = the forward facing angle between the stem and the UIWL. If the stem forms a fair curve within the ice belt as defined in 4.1 it may be presented by a straight line between the points of intersection of the stem and the upper and lower limits of the ice belt. If there are sharp changes in the inclination of the stem the largest n1 is to be used. f3 = 1,2 , but not less than 1,0 f4 and Po are to be taken from Table 15.1 for the respective ice Class Notation and displacement. Table 15.1 - Factor f4 and power P0 for the determination of minimum propulsion machinery output for ships of ice classes ES1 and ES2 Ice class notation ES2 ES1 ES2 ES1 D [t] < 30 000 $ 30 000 f4 0,22 0,18 0,13 0,11 P0 370 0 3070 2100 D = displacement of the ship [t] as per 2.4.D need not to be taken as greater than 80 000 t. For ES2, no higher propulsion machinery output, P, than required for ES3 is necessary. Note The Finnish Administration may in special cases approve an propulsion machinery output below that required in accordance with 3.2 above. 3.3 For ships with the ice Class Notation ES1 or ES2, the keels of which are laid or which are in a similar stage of construction on or after September 1st , 2003, and for ships with the ice class notation ES3 or ES4, the propulsion machinery output is not to be less than : P = [kW] Pmin = 2800 kW for ice class notation ES4 = 1000 kW for ice class notation ES1, ES2 and ES3 The required propulsion machinery output P is to be calculated for ships on both the UIWL and the LIWL. The propulsion machinery output shall not be less than the greater of these two outputs. Ke = is be taken from Table 15.2 The values in Table 15.2 apply only to conventional propulsion systems. Other methods may be used for determining the Ke values for advanced propulsion systems as specified in 3.4. BKI - Rules Volume II - 2014
- 224. A Section 15 - Strengthening for Navigation in Ice15-4/17 Table 15.2 Factor Ke for the determinationofminimumpropulsionmachinery output for ships of ice classes ES3 and ES4 Propeller type or machinery Ke CP or electric or hydraulic propulsion machinery FP propeller 1 propeller 2,03 2,26 2 propellers 1,44 1,60 3 propellers 1,18 1,31 DP = diameter of the propeller(s) [m] RCH = resistance [N] of the ship in a channel with brash ice and a consolidated layer : RCH = C1 + C2 + C3 @ Cμ ( HF + HM )2 @ (B + Cψ @ HF) + C4 @ LPAR @ + C5 [N] C1 and C2 take into account a consolidated upper layer of the brash ice and can be taken as zero for ice Class Notations ES1, ES2 and ES3. For ice class ES4 : C1 = f1 @ (f2 @ B + f3 @ LBOW + f4 @ B @ LBOW) C2 = (1 + 0,063 n1) (g1 + g2 @ B) + g3 C3 = 845 [kg/m2 /s2 ] C4 = 42 [kg/m2 /s2 ] C5 = 825 [kg/s2 ] Cμ = 0,15 cos n2 + sin ψ @ sin α; Cμ $ 0,45 Cψ = 0,047 ψ – 2,115; Cψ = 0 for ψ # 45° HF = thickness of the brash ice layer displaced by the bow [m] = 0,26 + HM = thickness of the brash ice in mid channel [m] = 1,0 for ice class notations ES3 and ES4 = 0,8 for ice class notations ES2 = 0,6 for ice class notation ES1 The ship parameters defined below are to be calculated on the UIWL using a horizontal waterline passing through the maximum ice class draught amidships, as defined in 2.1, and on the LIWL using a horizontal waterline passing through the minimum ice class draught amidships, as defined in 2.3. The ship dimensions LPP and B, however, are always to be calculated on the UIWL. See also Fig. 15.1. The lengths of the bow, LBOW, on the UIWL and LIWL are both to be measured from the fore perpendicular defined on the UIWL. The length of the parallel midship body, LPAR, is to be measured between the aft perpendicular and the flat of side, if the vessel has a full beam between these two points. LPAR = length of the parallel midship body [m] LPP = length of the ship between perpendiculars [m] LBOW = length of the bow [m] T = maximum and minimum ice class draughts amidship [m] according to 2.1 and 2.3, respectively BKI - Rules Volume II - 2014
- 225. Section 15 - Strengthening for Navigation in Ice A 15-5/17 Awf = area of the waterplane of the bow [m2 ] n1 = the rake of the stem at the centreline [°] For a ship with a bulbous bow, n1 shall be taken as 90°. n2 = the rake, of the bow at B/4 [°], n2max = 90° α = the angle of the waterline at B/4 [°] ψ = arctan The quantity is not to be taken less than 5 and not to be taken more than 20. f1 = 23 [N/m2 ], g1 = 1 530 [N] f2 = 45,8 [N/m], g2 = 170 [N/m] f3 = 14,7 [N/m], g3 = 400 [N/m1,5 ] f4 = 29 [N/m2 ] Ship's parameters are generally to be within the ranges of validity shown in Table 15.3 if the above formula for RCH is to be used. Otherwise, alternative methods for determining RCH are to be used as specified in 3.4.When calculating the parameter DP/T, T shall be measured on the UIWL. Table 15.3 - Range of application of the formula for ship resistance RCH Parameter Minimum Maximum α [°] 15 55 n1 [°] 25 90 n2 [°] 10 90 Lpp [m] 65,0 250,0 B [m] 11,0 40,0 T [m] 4,0 15,0 LBOW/Lpp 0,15 0,40 LPAR/Lpp 0,25 0,75 Dp/T 0,45 0,75 Awf / (Lpp @ B) 0,09 0,27 3.4 For an individual ship, in lieu of the Ke or RCH values defined in 3.3, the use of Ke values based on more exact calculations or RCH values based on model tests may be approved (see also paragraph 7.4 of the Guidelines for the Application of the Finnish-Swedish Ice Class Rules). If RCH is determined using the rule formulae, then Ke can be determined by using direct calculations or the rule formulae. However, if RCH is determined using model tests, then propeller thrust should be calculated by direct calculations using the actual propeller data. Such approvals will be given on the understanding that they can be revoked if warranted by the actual performance of the ship in ice. The design requirement for ice classes is a minimum speed of 5 kn in the following brash ice channels : ES4 = HM = 1,0 m and a 0,1 m thick consoli-dated layer of ice ES3 = HM = 1,0 m ES2 = HM = 0,8 m ES1 = HM = 0,6 m 4. Definitions for ships notations ES1-ES4 BKI - Rules Volume II - 2014
- 226. A Section 15 - Strengthening for Navigation in Ice15-6/17 4.1 Ice belt 4.1.1 The ice belt is the zone of the shell plating which is to be strengthened. The ice belt is divided into regions as follows, see Fig. 15.2 : .1 Forward region F The region from the stem to a line parallel to and at the distance c aft of the borderline between the parallel midship region and the fore ship; c = 0,04 L, not exceeding 6 m for the ice Class Notation ES3 and ES4, not exceeding 5 m for the ice class notations ES1- ES2 = 0,02 L, not exceeding 2 m for the ice class notation ES. .2 Midship region M The region from the aft boundary of the region F, as defined in .1 to a line parallel to and at the distance c aft of the borderline between the parallel midbody region and the aft ship ; .3 Aft region A The region from the aft boundary of the region M, as defined in .2 to the stern; .4 Fore foot FF (for ice class notation ES4 only) The region below the ice belt from the stem to a position five main frame spaces abaft the point where the bow profile departs from the keel line; .5 Upper forward ice belt FU (for ice class notations ES3 and ES4 on ships with a speed v0 $ 18 kn only) The region from the upper limit of the ice belt to 2 m above it and from the stem to a position 0,2 L abaft the forward perpendicular. 4.1.2 The vertical extension of the regions F, M, and A is to be determined from Table 15.4. 4.1.3 On the shell expansion plan submitted for approval, the location of the UIWL, LIWL and the upper/lower limits of the ice belt, as well as the regions F, M and A (including FF and FU, if applicable), are to be clearly indicated. Table 15.4 - Vertical extension of the regions F, M and A Ice class notation Below LIWL [m] Above UIWL [m] ES, ESl ES2 ES3 ES4 0,5 0,5 0,6 0,75 0,4 0,4 0,5 0,6 4.1.4 The following terms are used in the formulae in B: a = frame spacing [m], longitudinal or transverse, taking into account the intermediate frames, if fitted. ReH = minimum nominal upper yield point for hull structural steel according to Section 2, B.2. R = unsupported span [m] of frames, web frames, stringer. See also Section 3, C.3. p = design ice pressure [N/mm2 ] according to B.2.2 h = design height of ice pressure area [m] according to B.2.1. The frame spacing and spans are normally to be measured in a vertical plane parallel to the centreline of the ship. However, if the ship's side deviates more than 20° from this plane, the frame spacing and spans shall be measured along the side of the ship. BKI - Rules Volume II - 2014
- 227. Section 15 - Strengthening for Navigation in Ice A, B 15-7/17 Fig. 15.1 - Rake of the stem n1 and rake of the bow n2 at B/4 from CL Fig. 15.2 Ice belt B. Requirements for the Notations ES1 – ES4 1. General 1.1 A typical ice load distribution is shown in Fig.15.3. Maximum pressures (pmax) occur at the frames, minimum pressures occur between frames, due to different flexural stiffness of frames and shell plating. Fig. 15.3 - Ice load distribution The formulae for determining the scantlings used in this Section are based on the following design loads : for frames : p = ( pmax + pmin ) [N/mm2 ] for shell plating : p1 = 0,75 p [N/mm2 ] p = design ice pressure as per 2.2. BKI - Rules Volume II - 2014
- 228. B Section 15 - Strengthening for Navigation in Ice15-8/17 1.2 The formulae given in this Section may be substituted by direct calculation methods, subject to approval by BKI. 2. Ice loads 2.1 An ice strengthened ship is assumed to operate in open sea conditions corresponding to a level ice thickness not exceeding h0. The design height, h, of the area actually under ice pressure is, however, assumed to be less than h0. The values for h0 and h are given in Table 15. 5. Table 15.5 - Ice thickness h0 and design height h Ice class notation h0 [m] h [m] ES, ES1 ES2 ES3 ES4 0,4 0,6 0,8 1,0 0,22 0,25 0,30 0,35 2.2 The design ice pressure is to be determined according to the following formula : p = cd @ c1 @ ca @ p0 [N/mm2 ] cd = k = Pmax = 740 kW for the ice class notation ES a, b = coefficients in accordance with Table 15.6 Table 15.6 - Coefficients a and b Region F M and A k 12 > 12 12 > 12 a b 30 230 6 518 8 214 2 286 D see A.2.4 P = total maximum output the propulsion machinery can continuously deliver to the propeller(s)[kW], see also A.3.1 c1 = coefficient in accordance with Table 15.7 ca = max. 1,0, min. 0,6 Ra = effective length [m] according to Table15.8 p0 = 5,6 N/mm2 (nominal ice pressure). Table 15.7 - Coefficient c1 Ice class notation Region F M A ES ES1 ES2 ES3 ES4 0,3 1,0 1,0 1,0 1,0 ! 0,50 0,70 0,85 1,00 ! 0,25 0,45 0,65 0,75 BKI - Rules Volume II - 2014
- 229. Section 15 - Strengthening for Navigation in Ice B 15-9/17 Table 15.8 - Effective length Ra Structure Type of framing Ra Shell Transverse frame spacing Longitudinal 2 x frame spacing Frames Transverse frame spacing Longitudinal span of frame Ice stringer span of stringer Web frame 2 x web frame spacing 3. Thickness of shell plating in the ice belt 3.1 The thickness of the shell plating is to be determined according to the following formulae: .1 transverse framing: t = 667 a + tc [mm] .2 longitudinal framing : t = 667 a + tc [mm] p1 see 1.1 f1 = 1,3 ! f1max = 1,0 f2 = 0,6 + , where h/a # 1 = 1,4 ! , where 1 < h/a # 1,8 tc = allowance for abrasion and corrosion [mm]. Usually tc amounts to 2 mm. If a special coating is applied and maintained, which by experience is shown to be capable to withstand the abrasion of ice, the allowance may be reduced to 1 mm. 3.2 Where the draught (e.g., in the ballast condition) is smaller than 1,5 m, or where the distance between the lower edge of the ice belt and the keel plate is smaller than 1,5 m, the thickness of the bottom plating in way of the ice belt region F is not to be less than required for the ice belt. In the same area the thickness of the plate floors is to be increased by 10 %. 3.3 Side scuttles are not to be situated in the ice belt. If the weather deck in any part of the ship is situated below the upper limit of the ice belt, see A.4.1.2 (e.g. in way of the well of a raised quarter decker), the bulwark is to have at least the same strength as is required for the shell in the ice belt. Special consideration has to be given to the design of the freeing ports. 3.4 For ships with the ice Class Notation ES4 the region FF according to A.4.1.1.4 shall have at least the thickness of the region M. 3.5 For ships with the ice Class Notation ES3 or ES4 and with a speed v0 $ 18 kn the region FU according to A.4.1.1.5 shall have at least the thickness of the region M. A similar strengthening of the bow region is also advisable for a ship with a lower service speed when it is evident that the ship will have a high bow wave, e.g. on the basis of model tests. 4. Frames, ice stringers, web frames 4.1 General 4.1.1 Within the ice-strengthened area, all frames are to be effectively attached to the supporting structures. Longitudinal frames are generally to be attached to supporting web frames and bulkheads by brackets. Brackets may be BKI - Rules Volume II - 2014
- 230. B Section 15 - Strengthening for Navigation in Ice15-10/17 omitted with an appropriate increase in the section modulus of the frame (see 4.3.1) and with the addition of heel stiffeners (heel stiffeners may be omitted on the basis of direct calculations, subject to approval by BKI). Brackets and heel stiffeners are to have at least the same thickness as the web plate of the frame and the free edge has to be appropriately stiffened against buckling. When a transverse frame terminates at a stringer or deck, a bracket or similar construction is to be fitted. When a frame is running through the supporting structure, both sides of the web are to be connected to the structure by direct welding, collar plate or lug. 4.1.2 For the ice Class Notation ES4, for the ice Class Notation ES3 within the regions F and M and for the ice class notations ES2 and ES1 within the region F the following applies : .1 Frames with webs which are not at perpendicular to the shell are to be supported against tripping by brackets, intercostal plates, stringers or similar at a distance not exceeding 1300 mm. .2 The frames are to be attached to the shell by double continuous welds. No scalloping is allowed except when crossing shell plate butts welds. .3 The web thickness of the frames is to be at least one half of the thickness of the shell plating and at least 9 mm, The latter minimum value is independent of the material factor k according to Section 2, B.2.1. However, the web thickness of frames need not exceed one half of the shell plating thickness required for a frame spacing of 0,45 m, assuming a yield stress for the plating not greater than that for the framing. .4 Where there is a deck, tank top, bulkhead, web frame or stringer in lieu of a frame, its plate thickness of this is to be as required in accordance with .3, to a depth corresponding to the height of adjacent frame. 4.1.3 For transverse framing above UIWL and below LIWL, as well as longitudinal framing below LIWL, the vertical extension of the ice strengthened framing bE is to be determined according to Table 15.9. Where the vertical extension of ice-strengthened transverse framing bE would extend beyond a deck or a tank top by not more than 250 mm, it may be terminated at that deck or tank top. For longitudinal framing above UIWL the vertical extension of the ice-strengthening should be extended up to and including the first frame above the upper edge of the ice belt. Additionally, the spacing between the longitudinal frames directly above and below the edge of the ice belt should be the same as the frame spacing in the ice belt. If the first frame above the ice belt is closer than approximately a/2 to the upper edge of the ice belt, then the same frame spacing as in the ice belt should be extended to the second frame above the upper edge of the ice belt. Table 15.9 Vertical extension bE of ice strengthened framing Ice class notation Region bE Above UIWL [m] Below LIWL [m] ES F, from stem to 0,075 L abaft it 1,0 1,0 ES1 ES2 ES3 F, from stem to 0,3 L abaft it 1,6 F, abaft 0,3 L from stem to aft boundary of region F 1,3 M 1,3 A 1,0 FU 1) 2,5 ES4 F, from stem to 0,3 L abaft it 1,2 To double bottom or below top of floors F, abaft 0,3 L from stem to aft boundary of region F 1,6 M 1,6 A 1,2 FU 1) 2,6 1) If required according to A.4.1.1.5. BKI - Rules Volume II - 2014
- 231. Section 15 - Strengthening for Navigation in Ice B 15-11/17 4.2 Transverse frames 4.2.1 The section modulus of a main, 'tweendeck or intermediate transverse frame is to be determined according to the following formula: W = [cm3 ] mt = m0 = coefficient according to Table 15.10. The boundary conditions referred to in Table 15.10 are those for the intermediate frames. Other boundary conditions for main frames and 'tweendeck frames are assumed to be covered by interaction between the frames. This influence is included in the m0 values. The load centre of the ice load is taken at R/2. Where less than 15 % of the span R, is situated within the ice-strengthening zone for frames as defined in 4.1.3, ordinary frame scantlings may be used. 4.2.2 Upper end of transverse framing 4.2.2.1 The upper end of the ice- strengthened part of all frames is to be attached to a deck or an ice stringer as per 4.4. Table 15.10 - Boundary conditions for transverse frames Boundary Condition m0 Example 7 Frames in bulk carrier with top wing tanks 6 Frames extending from the tank top to a single deck 5,7 Continuous frames between several decks or stringers 5 Frames extending between two decks only 4.2.2.2 Where a frame terminates above a deck or stringer, which is situated at or above the upper limit of the ice belt (see A.4.1.2), the part above the deck or stringer need not be ice-strengthened. In such cases, the upper part of the intermediate frames may be connected to the adjacent main or 'tweendeck frames by a horizontal member of the same scantlings as the main and 'tweendeck frames, respectively. Such intermediate frames may also be extended to the deck above and, if this is situated more than 1,8 m above the ice belt, the intermediate frame need not be attached to that deck, except in the forward region F. BKI - Rules Volume II - 2014
- 232. B Section 15 - Strengthening for Navigation in Ice15-12/17 4.2.3 Lower end of transverse framing 4.2.3.1 The lower end of the ice strengthened part of all frames is to be attached to a deck, inner bottom, tanktop or ice stringer as per 4.4. 4.2.3.2 Where an intermediate frame terminates below a deck, tanktop or ice stringer which is situated at or below the lower limit of the ice belt (see A.4.1.2), its lower end may be connected to the adjacent main or 'tweendeck frames by a horizontal member of the same scantlings as the respectively main and 'tweendeck frames, respectively. 4.3 Longitudinal frames The section modulus and the shear area of the longitudinal frames are to be determined according to the following formulae: .1 section modulus: W = [cm3 ] .2 shear area: A = [cm2 ] f3 = factor which takes account of the load distribution to adjacent frames = 1 - 0,2 h/a f4 = 0,6 m = boundary condition factor = 13,3 for a continuous beam with double end brackets = 11,0 for a continuous beam without double end bracket. Where the boundary conditions are considerably different from those of a continuous beam, e.g. in an end field, a smaller factor m may be determined 4.4 Ice stringers 4.4.1 Ice stringers within the ice belt The section modulus and the shear area of a stringer situated within the ice belt are to be determined according to the following formulae : .1 section modulus: W = [cm3 ] .2 shear area: A = [cm2 ] p @ h is not to be taken as less than 0,3 m = see 4.3 f5 = factor which takes account of the distribution of load to the transverse frames; to be taken as 0,9 4.4.2 Ice stringers outside the ice belt The section modulus and the shear area of a stringer situated outside the ice belt, but supporting frames subjected to ice pressure, are to be calculated according to the following formulae: BKI - Rules Volume II - 2014
- 233. Section 15 - Strengthening for Navigation in Ice B 15-13/17 .1 section modulus: W = [cm3 ] .2 shear area: A = [cm2 ] p @ h is not to be taken as less than 0,3 f6 = factor which takes account of the distribution of load to the transverse frames; to be taken as 0,95 m = see 4.3 hs = distance of the stringer to the ice belt [m] Rs = distance of the stringer to the adjacent ice stringer or deck or similar structure [m]. 4.4.3 Deck strips 4.4.3.1 Narrow deck strips abreast of hatches and serving as ice stringers are to comply with the section modulus and shear area requirements in 4.4.1 and 4.4.2 respectively. In the case of very long hatches, the product p @ h may be taken less than 0,30 but in no case less than 0,20. 4.4.3.2 When designing weatherdeck hatchcovers and their fittings, the deflection of the ship's sides due to ice pressure in way of very long hatch openings is to be considered. 4.5 Web frames 4.5.1 The load transferred to a web frame from a stringer or from longitudinal framing is to be calculated according to the following formula: P = p @ h @ e @ 103 [kN] p @ h is not to be taken as less than 0,3 e = web frame spacing [m]. In case the supported stringer is outside the ice belt, the load P may be multiplied by where hs and Rs shall be taken as defined in 4.4.2. 4.5.2 Shear area and section modulus For the case of simple support at the upper end and constraint at the lower end according to Fig. 15.4, shear area and section modulus can be calculated by the following formulae : shear area : A = [cm2 ] Q = P @ k1 [kN] k1 = 1 + or = , whichever is greater. BKI - Rules Volume II - 2014
- 234. B Section 15 - Strengthening for Navigation in Ice15-14/17 For the lower part of the web frame, the smallest RF within the ice belt is to be used. For the upper part, the biggest RF within the ice belt is to be taken. R, RF [m] according to Fig. 15.4. Fig. 15.4 - Lengths R and RF α = see Table 15.11 P = as in 4.5.1 section modulus : W = [cm3 ] M = P @ R @ k2 [kNm] k2 = Aa = actual shear area A = required shear area as above, but by using k1 = 1 + γ = see Table 15.11 4.5.3 For web frame configurations and boundary conditions than given in 4.5.2, a direct stress calculation is to be performed. The point of application of the load P is in each case to be chosen in relation to the arrangement of stringers and longitudinal frames so as to obtain the maximum shear and bending moments. 4.5.4 At any position of the web frame the equivalent stress due to bending and shear is to comply with the following condition : σv = 5. Stem 5.1 The stem may be made of rolled, cast or forged steel or of shaped steel plates. A sharp edged stem (see Fig. 15.5) improves the manoeuvrability of the ship in ice and is particularly recommended for ships less than 150m in length. 5.2 The plate thickness of a shaped plate stem and, in the case of a blunt bow, any part of the shell which forms an angle β (see Fig. 15.5) of 30o or more to the centre line in a horizontal plane, is to be calculated according to the formulae in 3.1 observing that: p1 = p a = smaller of the two unsupported widths of plate panel [m] BKI - Rules Volume II - 2014
- 235. Section 15 - Strengthening for Navigation in Ice B 15-15/17 Ra = spacing of vertical supporting elements [m] (see also Table 15.8) Fig. 15.5 Stem 5.3 The stem and the part of a blunt bow defined in 5.2 (if applicable), are to be supported by floors or brackets spaced not more than 0,6 m apart and having a thickness of at least half the plate thickness according to 5.2. The reinforcement of the stem shall extend from the keel to a point 0,75 m above UIWL or, in case an upper forward ice belt is required (see also A.4.1.1) to the upper limit of the region FU. Table 15.11 - Coefficient a and . for the calculation of required shear area and section modulus 0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40 1,60 1,80 2,00 α 1,50 1,23 1,16 1,11 1,09 1,07 1,06 1,05 1,05 1,04 1,04 γ 0,00 0,44 0,62 0,71 0,76 0,80 0,83 0,85 0,87 0,88 0,89 Af = cross sectional area of free flange Aw = cross sectional area of web plate 6. Arrangements for towing 6.1 A mooring pipe with an opening not less than stated below is to be fitted in the bow bulwark at the centreline. size of opening : 250 x 300 [mm] length : 150 [mm] inner surface radius : 100 [mm] 6.2 A bitt or other means for securing a towline, dimensioned to withstand the breaking force of the towline of the ship, is to be fitted. Alternatively, two fairleads can be fitted symmetrically off the centreline with one bitt each. The bitts shall be aligned with the fairleads allowing the towlines to be fastened straight onto them. The installation of a centreline fairlead is still recommended, since it remains useful for many open water operations as well as some operations in ice. 6.3 On ships with a displacement not exceeding 30.000 t the part of the bow which extends to a height of a least 5 m above the UIWL and at least 3 m aft of the stem, is to be strengthened for the loads caused by fork towing. For this purpose intermediate frames and additional stringers or decks are to be fitted. Note Fork towing in ice is often the most efficient way of assisting ships of moderate size (as defined in 6.3). Ships with a bulb protruding more than 2,5 m forward of the forward perpendicular are often difficult to tow in this way. Some national authorities may deny assistance to such ships if the circumstances so warrant. 7. Stern 7.1 An extremely narrow clearance between the propeller blade tip and the stern frame is to be avoided as a small clearance would cause very high loads on the blade tips. 7.2 On twin and triple screw ships the ice strengthening of the shell and framing shall be extended to the double bottom to an extent of 1,5 m forward and aft of the side propellers. BKI - Rules Volume II - 2014
- 236. B Section 15 - Strengthening for Navigation in Ice15-16/17 7.3 Shafting and stern tubes of side propellers are normally to be enclosed within plated bossings. If detached struts are used, their design, strength and attachment to the hull are to be duly considered. 7.4 A wide transom stern extending below the UIWL will seriously impede the capability of the ship to back in ice, which is most essential. Therefore, a transom stern is not to extend below the UIWL if this can be avoided. If unavoidable, the part of the transom below the UIWL is to be kept as narrow was possible. The part of a transom stern situated within the ice belt shall be strengthened as for the midship region M. 7.5 Propulsion arrangements with azimuthing thrusters or "podded" propellers, which provide an improved manoeuverability, result in increased ice loading of the aft region and stern structure. Due consideration is to be given to this increased ice loading in the design and dimensioning of the aft region and stern structure. 8. Bilge keels To limit damage to the shell when a bilge keel is partly ripped off in ice, it is recommended that bilge keels are divided into several shorter independent lengths. 9. Rudder and steering gear 9.1 When calculating the rudder force and torsional moment according to Section 14, B.1. the ship's speed v0 is not to be taken less than given in Table 15.12. All scantlings dimensioned according to the rudder force and the torsional moment respectively (rudder stock, rudder coupling, rudder horn etc.) as well as the capacity of the steering gear are to be increased accordingly where the speed stated in Table 15.12 exceeds the ship's service speed. Independent of rudder profile the coefficient κ2 according to Section 14, B.1.1 need not be taken greater than κ2 = 1,1 in connection with the speed values given in Table 15.12. Table 15.12 - Minimum speed for the dimensioning of rudder Ice class notation v0 [kn] ES1 ES2 ES3 ES4 14 16 18 20 The factor κ3 according to Section 14, B.1.1 need not be taken greater than 1,0 for rudders situated behind a nozzle. 9.2 Within the ice belt (as per A.4.1) the thickness of the rudder plating is to be determined as of the shell plating within the region A. The thickness of webs shall not to be less than half the rudder plating thickness. 9.3 For the ice Class Notations ES3 and ES4, the rudder stock and the upper edge of the rudder are to be protected against ice pressure by an ice knife or equivalent means. Special consideration shall be given to the design of the rudder and the ice knife for vessels with a flap-type rudder. 9.4 For ships with the ice Class Notations ES3 and ES4 due regard is to be paid to the excessive arising when the rudder is forced out of the midship position while backing into an ice ridge. A locking device according to Section 14, G.2. is regarded sufficient to absorb these loads. Note For ships sailing in low temperature areas, small gaps between the rudder and ship's hull may cause the rudder to become fixed to the hull through freezing. It is therefore recommended to avoid gaps less than 1/20 of the rudder body width or 50 mm, whichever is less, or to install suitable means such as heating arrangements. BKI - Rules Volume II - 2014
- 237. Section 14 - Rudder and Manoeuvring Arrangement C 15-17/17 C. Requirements for the Ice Class Notation ES 1. Shell plating within the ice belt 1.1 Within the ice belt the shell plating shall have a strengthened strake extending over the forward region F the thickness of which is to be determined according to B.3. 1.2 The midship thickness of the side shell plating is to be maintained forward of amidships up to the strengthened plating. 2. Frames 2.1 In the forward region F the section modulus of the frames is to comply with the requirements given in B.4. 2.2 Tripping brackets spaces not more than 1,3 m apart are to be fitted within the ice belt in line with the tiers of beams and stringers required in Section 9, A.5. in order to prevent tripping of the frames. The tripping brackets are to be extended over the forward region F. 3. Stem The thickness of welded plate stems up to 600 mm above UIWL is to be 1,1 times the thickness required according to Section 13, B.2., however, need not exceed 25 mm. The thickness above a point 600 mm above the UIWL may be gradually reduced to the thickness required according to Section 13, B.2. BKI - Rules Volume II - 2014
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- 239. Section 16 - Superstructures and Deckhouses A 16-1/9 Section 16 Superstructures and Deckhouses A. General 1. Definitions 1.1 A superstructure is a decked structure on the freeboard deck extending from side to side of the ship or with the side plating not being inboard of the shell plating more than 0,04 B. 1.2 A deckhouse is a decked structure above the strength deck the side plating being inboard of the shell plating more than 0,04 B. 1.3 A long deckhouse is a deckhouse the length of which within 0,4 L amidships exceeds 0,2 L or 12 m, where the greater value is decisive. The strength of a long deckhouse is to be specially considered. 1.4 A short deckhouse is a deckhouse not covered by the definition given in 1.3. 1.5 Superstructures extending into the range of 0,4 L amidships and the length of which exceeds 0,15 L are defined as effective superstructures. Their side plating is to be treated as shell plating and their deck as strength deck (see Sections 6 and 7). 1.6 All superstructures being located beyond 0,4 L amidships or having a length of less than 0,15 L or less than 12 metres are, for the purpose of this Section, considered as non-effective superstructures. 1.7 For deckhouses of aluminium, Section 2, D. is to be observed. For the use of non-magnetic material in way of the wheel house, see Section 14, A.1.4. 1.8 Scantlings of insulated funnels are to be determined as for deckhouses. 1.9 Throughout this Section the following definitions apply: k = material factor according to Section 2, B.2 ps = load according to Section 4, B 2.1. pe = load according to Section 4, B 2.2. pD = load according to Section 4, B.1. pDA = load according to Section 4, B.5. pL = load according to Section 4, C.1. tK = corrosion addition according to Section 3, K. 2. Arrangement of superstructure 2.1 According to ICLL, Regulation 39, a minimum bow height is required at the forward perpendicular, which may be obtained by sheer extending for at least 0,15 Lc, measured from the forward perpendicular or by fitting a forecastle extending from the stem to a point at least 0,07 Lc abaft the forward perpendicular. 2.2 Ships carrying timber deck cargo and which are to be assigned the respective permissible freeboard, are to have a forecastle of the Rule height and a length of at least 0,07 Lc. Furthermore, ships the length of which is less than 100 m, are to have a poop of Rule height or a raised quarter deck with a deckhouse. 3. Strengthenings at the ends of superstructures 3.1 At the ends of superstructures one or both end bulkheads of which are located within 0,4 L amidships, the thickness of the sheer strake, the strength deck in a breadth of 0,1 B from the shell, as well as the thickness of the superstructure side plating are to be strengthened as specified in Table 16.1. The strengthenings shall extend over a region from 4 frame spacings abaft the end bulkhead to 4 frame spacings forward of the end bulkhead. Table 16.1 Strengthening [%] at the ends of superstructures Type of superstructure Strength deck and sheer strake Side plating of superstructure effective according to 1.5 30 20 non effective according to 1.6 20 10 BKI - Rules for Hull - 2014
- 240. A, B Section 16 - Superstructures and Deckhouses16-2/9 3.2 Under strength decks in way of 0,6 L amidships, girders are to be fitted in alignment with longitudinal walls, which are to extend at least over three frame spacings beyond the end points of the longitudinal walls. The girders are to overlap with the longitudinal walls by at least 2 frame spacings. 4. Transverse structure of superstructures and deckhouses The transverse structure of superstructures and deckhouses is to be sufficiently dimensioned by a suitable arrangement of end bulkheads, web frames, steel walls of cabins and casings, or by other measures. 5. Openings in closed superstructures 5.1 Allaccessopeningsinendbulkheadsofclosedsuperstructuresshallbefittedwith weathertight doors permanently attached to the bulkhead, having the same strength as the bulkhead. The doors shall be so arranged that they can be operated from both sides of the bulkhead. The coaming heights of the access opening above the deck are to be determined according to ICLL. 5.2 Any opening in a superstructure deck or in a deckhouse deck directly above the freeboard deck (deckhouse surrounding companionways), is to be protected by efficient weathertight closures. 6. Recommendations regarding deckhouse vibration 6.1 Thenaturalfrequenciesofthebasicglobaldeckhousevibrationmodes(longitudinal,transverse,torsional) should not coincide with major excitation frequencies at the nominal revolution rate of the propulsion plant. This should be verified during the design stage by a global vibration analysis. 6.2 The natural frequencies of local deck panel structure components (plates, stiffeners, deck frames, longitudinal girders, deck grillages) should not coincide with major excitation frequencies at the nominal revolution rate of the propulsion plant. This should be verified during the design stage by a local vibration analysis. 6.3 It is recommended to design the local deck structures in such a way that their natural frequencies exceed twice propeller blade rate, and in case of rigidly mounted engines ignition frequency, by at least 20 %. This recommendation is based on the assumption of a propeller with normal cavitation behaviour, i.e. significant decrease of pressure pulses with increasing blade harmonic shall be ensured. 6.4 Cantilever navigation bridge wings should be supportedbypillarsorbracketsextendingfromtheouterwing edge to at least the deck level below. If this is not possible, the attachment points of the pillars/brackets at the deckhouse structure have to be properly supported. 6.5 The base points of the main mast located on the compass deck should be preferably supported by walls or pillars. The natural frequencies of the basic main mast vibration modes (longitudinal, transverse, torsional) should not coincide with major excitation frequencies at the nominal revolution rate of the propulsion plant. This should be verified during the design stage by a mast vibration analysis. B. Side Plating and Decks of Non-Effective Superstructures 1. Side plating 1.1 The thickness of the side plating above the strength deck is not to be less than the greater of the following values: t = [mm] or t = 0,8 @ tmin [mm] p = ps or pe , as the case may be tmin = see Section 6, B. 3.1. 1.2 The thickness of the side plating of upper tier superstructures may be reduced if the stress level permits such reduction. 2. Deck plating 2.1 The thickness of deck plating is not to be less than the greater of the following values: t = [mm] t = [mm] p = pDA or pL, the greater value is to be taken. BKI - Rules for Hull - 2014
- 241. Section 16 - Superstructures and Deckhouses B, C 16-3/9 C = 1,21,if p = pDA = 1,1, if p = pL L need not be taken greater than 200 m. 2.2 Where additional superstructures are arranged on non-effective superstructures located on the strength deck, the thickness required by 2.1 may be reduced by 10 %. 2.3 Where plated decks are protected by sheathing, the thickness of the deck plating according to 2.1 and 2.2 may be reduced by tK, however, it is not to be less than 5 mm. Where a sheathing other than wood is used, attention is to be paid that the sheathing does not affect the steel. The sheathing is to be effectively fitted to the deck. 3. Deck beams, supporting deck structure, frames 3.1 The scantlings of the deck beams and the supporting deck structure are to be determined in accordance with Section 10. 3.2 The scantlings of superstructure frames are given in Section 9, A.3. C. Superstructure End Bulkheads and Deckhouse Walls 1. General The following requirements apply to superstructure end bulkheads and deckhouse walls forming the only protection for openings as per Regulation 18 of ICLL and for accommodations. These requirements also apply to breakwaters, see also F. 2. Definitions The design load for determining the scantlings is: pA = n @ c ( b @f– z ) [kN/m2 ] f = cL @ c0 cL, c0= see Section 4,A.2.2 hN = standard superstructure height = 1,05 + 0,01 L [m] , 1,8 < hN < 2,3 n = for the lowest tier of unprotected fronts. The lowest tier is normally that tier which is directly situated above the uppermost continuous deck to which the Rule depth H is to be measured. However, where the actual distance H - T exceeds the minimum non-corrected tabular freeboard according to ICLL by at least one standard superstructure height hN, this tier may be defined as the 2nd tier and the tier above as the 3rd tier = for 2nd tier unprotected fronts = for 3rd tier and tiers above of unprotected fronts, for sides and protected fronts = for aft ends abaft of amidships = for aft ends forward of amidships = for breakwaters forward of $ 0,85 L need not be taken greater than 300 m. b = 1,0 + for < 0,45 BKI - Rules for Hull - 2014
- 242. C Section 16 - Superstructures and Deckhouses16-4/9 b = 1,0 + 1,5 for 0,45 b = 1,0 + 2,75 for breakwaters forward of 0,85 0,60 CB 0,80; when determining scantlings of aft ends forward of amidships, CB need not be taken less than 0,8. x = distance [m] between the bulkhead considered or the breakwater and the aft end of the length L. When determining sides of a deckhouse, the deckhouse is to be subdivided into parts of approximately equal length, not exceeding 0,15 L each, and x is to be taken as the distance between aft end of the length L and the centre of each part considered. z = vertical distance [m] from the summer load line to the midpoint of stiffener span, or to the middle of the plate field. c = 0,3 + 0,7 b'/B' For exposed parts of machinery casings and breakwaters, c is not to be taken less than 1,0. b' = breadth of deckhouse at the position considered B' = actual maximum breadth of ship on the exposed weather deck at the position considered. b'/B' is not to be taken less than 0,25. a = spacing of stiffeners [m] R = unsupported span [m]; for superstructure end bulkheads and deckhouse walls, R is to be taken as the superstructure height or deckhouse height respectively, however, not less than 2,0 m. The design load pA up to the third tier inclusive is not to be taken less than the minimum values given in Table 16.2. For breakwaters, the minimum design load is to be the same as for the lowest tier of unprotected fronts. Table 16.2 Minimum design load pAmin L pAmin [kN/m2 ] for lowest tier of unprotected fronts and breakwaters elsewhere 50 30 15 > 50 250 250 50 25 For the 4th tier and all following ones pAmin is to be taken as 12,5 kN/mm2 3. Scantlings 3.1 Stiffeners The section modulus of the stiffeners is to be determined according to the following formula: W = 0,35 @ a @ R2 @ pA @ k [cm3 ] These requirements assume the webs of lower tier stiffeners to be efficiently welded to the decks. Scantlings for other types of end connections may be specially considered. The section modulus of house side stiffeners needs not be greater than that of side frames on the deck situated directly below; taking account of spacing a and unsupported span R. 3.2 Plate thickness The thickness of the plating is to be determined according to the greater values of the following formula : t = 0,9 @ a [mm] tmin = [mm] for the lowest tier and for breakwaters BKI - Rules for Hull - 2014
- 243. Section 16 - Superstructures and Deckhouses C, D 16-5/9 = [mm] for the upper tiers, however not less than 5 mm for tug 4,5 mm L need not be taken greater than 300 m. D. Decks of Short Deckhouses 1. Plating The thickness of deck plating exposed to weather but not protected by sheathing is not to be less than: t = 8 @ a + tK [mm] For weather decks protected by sheathing and for decks within deckhouses the thickness may be reduced by tK. In no case the thickness is to be less than the minimum thickness tmin = 5,0 mm. 2. Deck beams The deck beams and the supporting deck structure are to be determined according to Section 10. E. Elastic Mounting of Deckhouses 1. General 1.1 The elastic mountings are to be type approved by BKI. The stresses acting in the mountings which have been determined by calculation are to be proved by means of prototype testing on testing machines. Determination of the grade of insulation for transmission of vibrations between hull and deckhouses is not part of this type approval. 1.2 The height of the mounting system is to be such that the space between deck and deckhouse bottom remains accessible for repair, maintenance and inspection purposes. The height of this space shall normally not be less than 600 mm. 1.3 For the fixed part of the deckhouse on the weather deck, a coaming height of 380 mm is to be observed, as required by ICLL for coamings of doors in superstructures which do not have access openings to under deck spaces. 1.4 For pipelines, see Rules for Machinery Installations, Volume III, Section 11. 1.5 Electric cables are to be fitted in bends in order to facilitate the movement. The minimum bending radius prescribed for the respective cable is to be observed. Cable glands are to be watertight. For further details, see Rules for Electrical Installations, Volume IV. 1.6 The following scantling requirements forrails, mountings, securingdevices,stoppersand substructures in the hull and the deckhouse bottom apply to ships in unrestricted service. For special ships and for ships intended to operate in restricted service ranges requirements differing from those given below may be applied. 2. Design loads For scantling purposes the following design loads apply: 2.1 Weight 2.1.1The weight induced loads result from the weight of the fully equipped deckhouse, considering also the acceleration due to gravity and the acceleration due to the ship's movement in the seaway. The weight induced loads are to be assumed to act in the centre of gravity of the deckhouse. The individual dimension less accelerations az (vertically), ay (transversely) and ax (longitudinally) and the dimension less resultant acceleration aβ, are to be determined according to Section 4, E. for k = 1,0 and f = 1,0. Due to the resultant acceleration aβ the following load is acting: P = [kN] G = mass of the fully equipped deckhouse [t] g = 9,81 m/s2 2.1.2The support forces in the vertical and horizontal directions are to be determined for the various angles β. The scantlings are to be determined for the respective maximum values (see also Fig. 16.1). BKI - Rules for Hull - 2014
- 244. E Section 16 - Superstructures and Deckhouses16-6/9 Fig. 16.1 Support forces 2.2 Water pressure and wind pressure 2.2.1The water load due to the wash of the sea is assumed to be acting on the front wall in the longitudinal direction only. The design load is : pwa = 0,5 @ pA [kN/m2 ] pA = see C.2 The water pressure is not to be less than : pwa = 25 [kN/m2 ] at the lower edge of the front wall = 0 at the level of the first tier above the deckhouse bottom Pwa = pwa @ Af [kN] Af = loaded part of deckhouse front wall [m2 ] 2.2.2The design wind load acting on the front wall and on the side walls is: Pwi = AD @ pwi [kN] AD = area of wall [m2 ] pwi = 1,0 [kN/m2 ] 2.3 Load on the deckhouse bottom The load on the deckhouse bottom is governed by the load acting on the particular deck on which the deckhouse is located. Additionally, the support forces resulting from the loads specified in 2.1 and 2.2 are to be taken into account. 2.4 Load on deck beams and girders For designing the deck beams and girders of the deck on which the deckhouse is located the following loads are to be taken: .1 Below the deckhouse: Load pu according to the pressure head due to the distance between the supporting deck and the deckhouse bottom [kN/m2 ]. .2 Outside the deckhouse: Load pD. .3 Bearing forces in accordance with the load assumptions 2.1 and 2.2. 3. Load cases 3.1 For design purposes the following load cases are to be investigated separately (see also Fig. 16.2) : Fig. l6.2Design loads due to wind and water pressure BKI - Rules for Hull - 2014
- 245. Section 16 - Superstructures and Deckhouses E 16-7/9 3.2 Service load cases Forces due to external loads: 3.2.1Transverse direction (z-y-plane) Py1 = G @ aβ(y) @ g + Pwi [kN] acting in transverse direction Pz1 = G @ aβ(z) @ g [kN] acting vertically to the baseline Pwi = wind load as per 2.2.2 aβ(y) = horizontal acceleration component of aβ aβ(z) = vertical acceleration component of aβ. 3.2.2 Longitudinal direction (z-x-plane) Px1 = G @ aβ(x) @ g + Pwa + Pwi [kN] acting in longitudinal direction Pz1 = G @ aβ(z) @ g [kN] acting vertically to the baseline aβ(x) = horizontal acceleration component in the longitudinal plane. 3.2.3For designing the securing devices to prevent the deckhouse from being lifted, the force (in upward direction) is not to be taken less than determined from the following formula: Pzmin = 0,5 @ g @ G [kN] 3.3 Extraordinary load cases 3.3.1Collision force in longitudinal direction: Px2 = 0,5 @ g @ G [kN] 3.3.2Forces due to static heel of 45E Pz2,Py2 = 0,71 @ g @ G [kN] Pz2 = force acting vertically to the baseline Py2 = force acting in transverse direction. 3.3.3The possible consequences of a fire for the elastic mounting of the deckhouse are to be examined (e.g. failure of rubber elastic mounting elements, melting of glue). Even in this case, the mounting elements between hull and deckhouse bottom shall be capable of withstanding the horizontal force Py2 as per 3.3.2 in transverse direction. 3.3.4For designing of the securing devices to prevent the deckhouse from being lifted, a force not less than the buoyancy force of the deckhouse resulting from a water level of 2 m above the freeboard deck is to be taken. 4. Scantlings of rails, mounting elements and substructures 4.1 General 4.1.1The scantlings of those elements are to be determined in accordance with the load cases stipulated under 3. The effect of deflection of main girders need not be considered under the condition that the deflection is so negligible that all elements take over the loads equally. 4.1.2Strength calculations for the structural elements with information regarding acting forces are to be submitted for approval. 4.2 Permissible stresses 4.2.1The permissible stresses given in Table 16.3 are not to be exceeded in the rails and the steel structures of mounting elements and in the substructures (deck beams, girders of the deckhouse and the deck, on which the deckhouse is located). 4.2.2The permissible stresses for designing the elastic mounting elements of various systems will be considered from case to case. Sufficient data are to be submitted for approval. 4.2.3The stresses in the securing devices to prevent the deckhouse from being lifted are not to exceed the stress values BKI - Rules for Hull - 2014
- 246. E Section 16 - Superstructures and Deckhouses16-8/9 specified in 4.2.1. 4.2.4In screwed connections, the permissible stresses given in Table 16.4 are not to be exceeded. Table 16.3 Permissible stress in the rails and the steel structures at mounting elements and in the substructures [N/mm2 ] Type of stress service load cases extraordinary load cases normal stress σn 0,6 @ ReH or 0,4 @ Rm 0,75 @ ReH or 0,5 @ Rm shear stress τ 0,35 @ ReH or 0,23 @ Rm 0,43 @ ReH or 0,3 @ Rm equivalent stress 0,75 @ ReH 0,9 @ ReH ReH = minimum nominal upper yield point Rm = tensile strength 4.2.5Where turnbuckles in accordance with DIN 82008 are used for securing devices, the load per bolt under load conditions 3.2.3 and 3.3.4 may be equal to the proof load (2 times safe working load). 5. Corrosion Addition For the deck plating below elastically mounted deckhouse a minimum corrosion addition of tK = 3.0 mm applies. Type of stress service load cases extra-ordinary load cases longitudinal tension σn 0,5 @ ReH 0,8 @ ReH bearing pressure pR 1,0 @ ReH 1,0 @ ReH equivalent stress from longitudinal tension σn, tension τt due to tightening torque and shear τ if applicable 0,6 @ ReH 1,0 @ ReH F. Breakwater 1. Arrangement If cargo is intended to be carried on deck forward of x/L $ 0,85, a breakwater or an equivalent protecting structure (e.g. whaleback or turtle deck) is to be installed. 2. Dimensions of the breakwater 2.1 The recommended height of the breakwater is hw = [mm] but shall not be less than hwmin = [mm] where z is to be the vertical distance [m] between the summer load line and the bottom line of the breakwater. The average height of whalebacks or turtle decks has to be determined analogously. 2.2 The breakwater has to be at least as broad as the width of the area behind the breakwater, intended for carrying deck cargo. BKI - Rules for Hull - 2014
- 247. Section 16 - Superstructures and Deckhouses F 16-9/9 3. Cutouts Cutouts in the webs of primary supporting members of the breakwater are to be reduced to their necessary minimum. Free edges of the cutouts are to be reinforced by stiffeners. If cutouts in the plating are provided to reduce the load on the breakwater, the area of single cutouts should not exceed 0,2 m2 and the sum of the cutout areas not 4. Loads The loads for dimensioning are to be taken accordingly from C.2. 5. Plate thickness and stiffeners 5.1 The plate thickness has to be determined according to C.3.2. 5.2 The section moduli of the stiffeners are to be calculated according to C.3.1. Stiffeners are to be connected on both ends to the structural members supporting them. 6. Primary supporting members For primary supporting members of the structure a stress analysis has to be carried out. Sufficient supporting structures are to be provided. The permissible equivalent stress is σv = 230/k [N/mm2 ]. 7. Proof of buckling strength Structural members' buckling strength has to be proved according to Section 3, F. BKI - Rules for Hull - 2014
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- 249. Section 17 - Hatchways A 17-1/20 Section 17 Hatchways A. General 1. Hatchways on freeboard and superstructure decks 1.1 The hatchways are classified according to their position as defined in Section 1, H.6.7. 1.2 Hatchways are to have coamings, the minimum height of which above the deck is to be as follows: In position 1: 600 mm. In position 2: 450 mm. 1.3 Adeviationfromtherequirementsunder1.2mayonlybegrantedforhatchwaysonexposeddeckswhichare closed by weathertight, self tightening steel covers. The respective exemption, in accordance with IC LL Regulation 14(1), has to be applied for in advance from the competent flag state authority. 1.4 Where an increased freeboard is assigned, the height of hatchway coamings according to 1.2 and the design load for hatch covers according to Table 17.2 on the actual freeboard deck may be as required for a superstructure deck, provided the summer freeboard is such that the resulting draught will not be greater than that corresponding to the minimum freeboard calculated from an assumed freeboard deck situated at a distance equal to a standard superstructure height below the actual freeboard deck. 1.5 For corrosion protection for all hatch coamings and all hatch covers of bulk carriers, ore carriers and combination carriers, see Section 38, G. Note SpecialrequirementsofNationalAdministrationsregardinghatchways,hatchcovers, tighteningandsecuringarrangements are to be observed. 2. Hatchways on lower decks and within superstructures 2.1 Coamings are not required for hatchways below the freeboard deck or within weathertight closed superstructures unless they are required for strength purposes. 2.2 For hatchways according to 2.1 wooden gratings instead of hatch covers may be used; hatch covers may also be dispensed with completely. 2.3 Where within hatch casings no hatchcoversare arrangedat thedecklevel,thenextcoversandtheirsupportsbelow are to be strengthened corresponding to the greater load. 3. Definitions p = design load [kN/m2 ] for hatch covers of respective load cases A to D according to B. = pH for vertical loading on hatch covers = pA for horizontal loading on edge girders of hatch covers and on coamings = liquid pressure p1, p2 according to Section 4,D.1. ReH = minimum nominal upper yield point of the steel used [N/mm2 ] according to Section 2,B.2. For hatch covers the application of steel which minimum nominal upper yield point exceeds 355 N/mm2 is not permitted. Rm = tensile strength of the steel used [N/mm2 ] For normal strength hull structural steel : Rm = 400 N/mm2 with ReH = 235 N/mm2 BKI - Rules for Hull - 2014
- 250. A, B Section 17 - Hatchways17-2/20 For higher strength hull structural steel : Rm = 440 N/mm² with ReH = 315 N/mm² = 490 N/mm² with ReH = 355 N/mm² R = unsupported span of stiffener [m] a = spacing of hatchway beams or stiffeners [m] t = thickness of structural member [mm] = tnet + tK tnet = net thickness [mm] tK = corrosion addition according to Table 17.1. B. Hatch Covers 1. Design loads Structural assessment of hatch covers and hatch coamings is to be carried out according to the following design loads: 1.1 Load case A: 1.1.1The vertical design load pH for weather deck hatch covers is to be taken from Table 17.2 unless higher design loads are requested by the owner. 1.1.2The design load for hatch covers of decks the height of which above baseline is z > zfb + 2 @ hN may be reduced, if the Administration concerned agrees and if it is verified that the load capacity of the hatch cover corresponds at least to that of the deck beside. zfb = required height of the freeboard deck above baseline [m] according to ICLL hN = superstructure standard height according to ICLL = [m] for 1.1.3 The vertical design load pH shall in no case be less than the deck design load according to Section 4, B.1. Instead of the deck height z the height of hatch cover plating above baseline is then to be inserted. 1.1.4 The horizontal design load pA for the outer edge girders of weather deck hatch covers and of hatch coamings is to be determined analogously as for superstructure walls in the respective position. For bulk carriers according to Section 23 the horizontal load shall not be less than: PAmin = 175 kN/m2 in general for outer edge girders of hatch covers = 220 kN/m2 in general for hatch coamings = 230 kN/m2 for the forward edge girder of the hatch 1 cover, if no forecastle according to Section 23, D is arranged = 290 kN/m2 for the forward transverse coaming of hatch 1, if no forecastle according to Section 23, D is arranged 1.2 Load case B: Where cargo is intended to be carried on hatch covers of decks in pos. 1 and 2 hatch covers, they are to be designed for the loads as given in Section 4, C.1. If cargo with low stowage height is carried on weather deck hatch covers Section 4, B.13 is to be observed. BKI - Rules for Hull - 2014
- 251. Section 17 - Hatchways B 17-3/20 Table 17.1 - Corrosion addition for hatch coamings and hatch covers Application Structure tK (mm) Weather deck hatches of container ships, car carriers, paper carriers, passenger vessels Hatch covers: - Weather exposed plating - Remaining structure 1,3 1,0 Hatch coamings according to Section 3, K.1. Weather deck hatches of all other ship types (e.g. multi-purpose dry cargo ships) Hatch covers in general: Load Case A,D Load Case B,C,E1 - weather exposed plating 2,0 1,5 - remaining structure 2,0 1,2 Double skin hatch covers and closed box girders - weather exposed plating and bottom plating 1,5 (2,0)2 - inner structures 1,0 (1,5)2 - remaining structures 1,2 Hatch coamings not part of the longitudinal hull structure 1,5 Hatch coamings part of the longitudinal hull structure according to Section 3, K.1. Coaming stays and stiffners 1,5 Hatches within enclosed spaces Hatch covers : - top plating 1,2 - remaining structures 1,0 Hatch covers and coamings according to Section 3, K.1. to K.3. 1) The tk-values for load case A, B, C and E respectively are to be indicated in the drawings. 2) The tk-values in brackets are to be applied to bulk carriers according to the definition of IACS Common Structural Rules (See Section 23, B.1.4) 1.3 Load case C: Where containers, which are not horizontally supported, are stowed on hatch covers of hatch in pos. 1 and 2 the following loads due to the ship's rolling motion are to be considered, see also Fig. 17.1. Az = 9,81 @ (1 + av) [kN] Bz = 9,81 @ (1 + av) [kN] By = 2,4 @ M [kN] av = acceleration factor according to section 4,C.1 M = mass of container stack [t] hm = height of centre of gravity of stack above hatch cover supports [m] For M and hm those values shall be used, which are calculated using non reduced acceleration values according to Rules for Stowage and Lashing of Containers, Section 3, A. b = distance between footpoints [m] Az, Bz, By = support forces in y-, z- direction at the stack corners. BKI - Rules for Hull - 2014
- 252. B Section 17 - Hatchways17-4/20 Table 17.2 - Design load of weather deck hatches Position Design load pH [kN/m2 ] 1 for m for m 9,81 @ 3,5 for type B ships according to ICLL for ships with less freeboard then type B ships according to ICLL , with 2 for m for m 9,81 @ 2,6 9,81 @ 3,5 Fig. 17.1 Forces due to load case C acting on hatch cover 1.3.1Load cases with partial loading TheloadcasesBandC arealsotobeconsidered forpartialloadingwhichmayoccurinpractice,e.g.wherespecifiedcontainer stack places are empty. The design load for other cargo than containers subject to lifting forces is to be determined separately. 1.3.2 In case of container stacks secured to lashing bridges or carried in cell guides the forces acting on the hatch cover are to be considered. 1.4 Load case D: Hatch covers of hold spaces intended to be filled with liquids are to be designed for the loads specified in Section 4, D.1. and D.2. irrespective of the filling height of hold spaces. BKI - Rules for Hull - 2014
- 253. Section 17 - Hatchways B 17-5/20 1.5 Load case E: Hatch covers, which in addition to the loads according to 1. are loaded in the ship's transversedirectionbyforcesduetoelastic deformations of the ship's hull, are to be so designed that the sum of stresses does not exceed the permissible values given in 2. 1.6 Load case F: Tweendeck hatch covers not subject to cargo loads are to be designed for a uniformly distributed load of 2 kN/m2 or for a single load of 3 kN, whichever results in the stronger scantlings. 1.7 Horizontal mass forces For the design of the securing devices against shifting according to 4.7 the horizontal mass forces in ship's longitudinal and transverse direction are to be calculated. For this purpose the following acceleration component are to be used: ax = 0,2 @ g [m/s2 ] in longitudinal direction ay = 0,5 @ g [m/s2 ] in transverse direction 2. Permissible stresses and deflections 2.1 The equivalent stress in steel hatch cover structures related to the net thickness shall not exceed 0,8 . ReH.v [N/mm2 ] F = Fb = bending stress Fn = normal stress J = shear stress The deflection f of weather deck hatch covers under the design load pH shall not exceed f = 0,0056 Rg Rg = largest span of girders [m] Note : Where hatch covers are arranged for carrying containers and mixed stowage is allowed i.e. a 40'-container on stowages places for two 20'-containers, the deflections of hatch covers have to be particularly observed. 2.2 Where hatch covers are made of aluminium alloys. Section 2, D. is to be observed. For permissible deflections 2.1 applies. 2.3 Thepermissiblestressesspecifiedunder2.1applytoprimarygirdersofsymmetricalcrosssection.Forunsymmetrical cross sections, e.g. - sections, equivalence in regard to strength and safety is to be proved, see also Section 3, L. 3. Strength calculation for hatch covers 3.1 General Calculations are to be based on net thickness: The tK values used for calculation have to be indicated in the drawings. Verifications according to Section 3, F. are to be based on t = tnet and stresses corresponding to tnet applying the safety factor S = 1,1. Forallstructuralcomponentsofhatchcoversforspacesinwhichliquidsarecarried,theminimumthicknessfortanksaccording to Section 12, A.7. is to be observed. BKI - Rules for Hull - 2014
- 254. B Section 17 - Hatchways17-6/20 3.2 Hatch cover supports Supports and stoppers of hatch covers are to be so arranged that no constraints due to hull deformations occur in the hatch cover structure and at stoppers respectively, see also load case E. Deformations due to the design loads according to 1. between coaming and weathertight hatch covers, as well as between coaming and covers for hold spaces in which liquids are carried, shall not lead to leakiness. Iftwoormoredeckpanels are arranged on one hatch, clearancesinforcetransmittingelementsbetweenpanelshavegenerally to be observed. For bulk carriers according to Section 23 each panel has to be assumed as independently load-bearing. Stiffness of securing devices, where applicable, and clearances are to be considered. 3.3 Strength calculations for beam and girder grillages Cross-sectional properties are to be determined considering the effective breadth according to Section 3, E. Cross sectional areas of profiles parallel to the girder web within the effective breadth can be included, see Section 3, F. The effective width of flange plates under compression with stiffeners perpendicular to the girder web is to be determined according to Section 3, F.2.2. In way of larger cutouts in girder webs it may be required to consider second order bending moments. 3.4 FEM calculations Forstrengthcalculationsofhatchcoversbymeansoffiniteelements,thecovergeometryshallbeidealisedbuiltasrealistically as possible. Element size shall be appropriate to account for effective breadth. In no case element width shall be larger than stiffener spacing. In way of force transfer points and cutouts the mesh has to be refined where applicable. The ratio of element length to width shall not exceed 2. The element height of girder webs shall not exceed half the web height. Stiffeners, supporting plates against lateral loads, have to be included in the idealization. Buckling stiffeners may be disregarded for the stress calculation. 4. Scantlings 4.1 Hatch cover plating 4.1.1Top plating The thickness of the hatch cover top plating is to be obtained from the calculation according to 3. However, the thickness shall not be less than the largest of the following values : t = [mm] = [mm] t = [mm] tmin = 6,0 mm cp = for p = pH = for p from pD, cargo load or liquid pressure Fx = bending stress [N/mm2 ] of main girder at a distance a/2 of the girder web, see Section 3, F. For flange plates under compression sufficient buckling strength according to Section 3, F. is to be verified. For hatch covers subject to wheel loading plate thickness shall not be less than according to Section 7, B.2. BKI - Rules for Hull - 2014
- 255. Section 17 - Hatchways B 17-7/20 4.1.2Lower plating of pontoon hatch covers and box girders The thickness is to be obtained from the calculation according to 3. The thickness shall not be less than the larger of the following values : t = [mm] tmin = 6,0 mm The lower plating of hatch covers for spaces in which liquids are carried is to be designed for the liquid pressure and the thickness is to be determined according to 4.1.1. 4.2 Main girders Scantlingsofmaingirdersareobtainedfromthecalculationaccordingto3.underconsiderationofpermissiblestressesaccording to 2. For all components of main girders sufficient safety against bucklingshallbeverified. For biaxially compressed flange plates thisistobeverifiedwithintheeffectivewidths.Atintersectionsofflangesfromtwogirders,notchstresseshavetobeobserved. The thickness of main girder webs shall not be less than : t = [mm] tmin = 6,0 mm For hatch covers of bulk carriers according to Section 23 the ratio of flange width to web height shall not exceed 0,4, if the unsupportedlengthoftheflangebetween two flange supports of main girders is largerthan3,0m. Theratioofflangeoutstand to flange thickness shall not exceed 15. 4.3 Edge girders 4.3.1 Scantlingsofedgegirders are obtained fromthe calculationsaccordingto3.Thethicknessoftheouteredge girders exposed to wash of sea shall not be less than the largest of the following values : t = [mm] = [mm] t = [mm] tmin = 6,0 mm 4.3.2 The stiffness of edge girders of weather deck hatch covers is to be sufficient to maintain adequate sealing pressure between securing devices. The moment of inertia of edge elements is not to be less than: I = [cm4 ] q = packing line pressure [N/mm], minimum 5 N/mm s = spacing [m] of securing devices 4.3.3 For hatch covers of spaces in which liquids are carried, the packing line pressure shall also be ensured in case of hatch cover loading due to liquid pressure. 4.4 Hatch cover stiffeners The section modules Wnet and shear area Asnet of uniformly loaded hatch cover stiffeners constraint at both ends shall not be less than : [cm3 ] [cm2 ] Stiffeners paralleltomaingirderwebsandarrangedwithintheeffectivebreadth according to Section 3, E. shall be continuous at transverse girders and may be regarded for calculating the cross sectional properties of main girders. It is to be verified BKI - Rules for Hull - 2014
- 256. B Section 17 - Hatchways17-8/20 that the resulting stress from main girders and hatch cover stiffeners does not exceed the permissible stress according to 2. If hatch cover stiffeners are sniped at the edge girders, Wnet is to be increased by 50 % The thickness of hatch cover plating at sniped stiffener ends shall not be less than the thickness according to Section 3, D.3. For hatch cover stiffeners under compression sufficient safety against lateral and torsional buckling according to Section 3, F. is to be verified. For hatch covers subject to wheel loading stiffener scantlings are to be determined by direct calculations. 4.5 Hatch cover supports 4.5.1Hatch covers, which are intended to carry cargo, are to be additionally secured against shifting in the longitudinal and transverse direction due to the acting mass forces specified in 1.7. For the transmission of the support forces resulting from the load cases specified in 1.1 - 1.7, supports are to be provided which are to be designed such that the nominal surface pressures in general do not exceed the following values: pn max = [N/mm2 ] d = dmax = 3,0 dmin = 1,0 in general = 2,0 for partial loading conditions (see 1.3.1) pn = see Table 17.3 Table 17.3 - Permissible nominal surface pressure pn Support material pn [N/mm2 ] when loaded by Vertical force Horizontal force hull structural steels 25 40 hardened steels 35 50 plastic materials on steel 50 - For metallic supporting surfaces not subjected to relative displacements the following applies: pn max = 3 @ pn [N/mm2 ] Where large relative displacements of the supporting surfaces are to be expected, the use of material having low wear and frictional properties is recommended. 4.5.2Drawings of the supports shall be submitted. In the drawings of the supports the permitted maximum pressure given by the material manufacturer related to long time stress is to be specified. 4.5.3If necessary, sufficient abrasive strength may be shown by tests demonstrating an abrasion of support surfaces of not more than 0,3 mm per one year in service at a total distance of shifting of 15 000 m/year. 4.5.4The substructures of the supports have to be of such a design, that a uniform pressure distribution is achieved. 4.5.5Irrespectiveofthearrangementofstoppers,thesupportsshallbeabletotransmitthefollowingforcePh inthelongitudinal and transverse direction: Ph = [kN] Pv = vertical supporting force [kN]. : = frictional coefficient = 0,5 for steel on steel BKI - Rules for Hull - 2014
- 257. Section 17 - Hatchways B 17-9/20 = 0,35 for non-metallic, low-friction support materials on steel 4.5.6Supports,aswellastheadjacentstructuresandsubstructuresaretobedesignedsuch thatthepermissibelstressesaccording to 2. are not exceeded. 4.5.7For substructures and adjacent constructions of supports subjected to horizontal forces Ph a fatigue strength analysis is to be carried out according to Section 20 by using the stress spectrum B and applying the horizontal force Ph. 4.6 Locking and securing of hatch covers 4.6.1Securing of weather deck hatch covers 4.6.1.1 Locking devices between cover and coaming and at cross-joints are to be provided to ensure weathertightness. Sufficient packing line pressure is to be maintained. The packing line pressure is to be specified in the drawings. Securing devices shall be appropriate to bridge displacements between cover and coaming due to hull deformations. 4.6.1.2 Securing devices are to be of reliable construction and effectively attached to the hatchway coamings, decks or covers. Individual securing devices on each cover are to have approximately the same stiffness characteristics. 4.6.1.3 Where rod cleats are fitted, resilient washers or cushions are to be incorporated. 4.6.1.4 Where hydraulic cleating is adopted, a positive means is to be provided to ensure that it remains mechanically locked in the closed position in the event of failure of the hydraulic system. 4.6.1.5 The spacing of securing devices shall generally not exceed 6 m. 4.6.1.6 Securing devices are to be provided at each corner of the hatch cover. This applies also to hatch covers consisting of several parts. 4.6.1.7 The net cross-sectional area of the securing devices is not to be less than: A = [cm2 ] q = packing line pressure [N/mm], minimum 5 N/mm s = spacing between securing devices [m], not to be taken less than 2 m = ReH is not to be taken greater than 0,70 Rm. e = 0,75 for ReH > 235 N/mm² = 1,00 for ReH # 235 N/mm² Rods or bolts are to have a net diameter not less than 19 mm for hatchways exceeding 5 m2 in area. 4.6.1.8 Thelockingelementsofhatchcovers,onwhichcargoistobelashed,aretobedesignedfortheliftingforcesaccording to 1., load case C. Unsymmetrical loadings, which may occur in practice, are to be considered. Under these loadings the equivalent stress in the securing devices is not to exceed: = [N/mm2 ] 4.6.1.9 Securing devices of hatch covers for spaces in which liquids are carried shall be designed for the lifting forces according to load case D. 4.6.1.10 Cargo deck hatch covers consisting of several parts have to be secured against accidental lifting. 4.7 Hatch cover stoppers Hatch covers shall be sufficiently secured against shifting. Stoppers are to be provided for hatch covers on which cargo is carried as well as for hatch covers, which edge girders have BKI - Rules for Hull - 2014
- 258. B Section 17 - Hatchways17-10/20 to be designed for pA > 175 kN/m2 . Design forces for the stoppers are obtained from the loads according to 1. The permissible stress in stoppers and their substructures in the cover and of the coamings is to be determined according to 2. 4.8 Cantilevers, load transmitting elements 4.8.1Cantilevers and load transmitting elements which are transmitting the forces exerted by hydraulic cylinders into the hatchway covers and the hull are to be designed for the forces stated by the manufacturer. The permissible stresses according to 2. are not to be exceeded. 4.8.2Structuralmemberssubjectedtocompressivestressesaretobeexaminedforsufficientsafetyagainstbuckling,according to Section 3, F. 4.8.3Particular attention is tobepaidtothe structural design in way of locations where loads are introduced into the structure. 4.9 Container seatings on hatch covers The seatings and their substructures are to be designed for the loads according to load case B and C respectively, applying the permissible stresses according to 2. 5. Weathertightness of hatch covers For weather deck hatch covers packings are to be provided, exception see 5.2 5.1 Packing material 5.1.1The packing material is to be suitable for all expected service conditions of the ship and is to be compatible with the cargoes to be transported. The packing material is to be selected with regard to dimensions and elasticity in such a way that expected deformations can be carried. Forces are to be carried by the steel structure only. The packings are to be compressed so as to give the necessary tightness effect for all expected operating conditions. Special consideration shall be given to the packing arrangementin ships with large relative movements betweenhatch covers and coamings or between hatch cover sections. 5.1.2If the requirements in 5.2 are fulfilled the weather tightness can be dispensed with. 5.2 Non-weathertightness hatch covers 5.2.1Upon request and subject to compliance with the following conditions the fitting of weather tight gaskets according to 5.1 may be dispensed with: 5.2.1.1 The hatchway coamings shall be not less than 600 mm in height. 5.2.1.2 The hatch covers are located above a depth H(x). H(x) is to be shown to comply with the following calculated criteria: H(x) $ Tfb + fb + hN + 4,6 [m] Tfb = draught corresponding to the assigned summer load line fb = freeboard determined in accordance with ICLL, relative to a deck height which is by hN + 4,6 m smaller than H(x) hN = 0 for # 0,75 [m] = 2,3 for > 0,75 [m] 5.2.1.3 Labyrinths are to be fitted proximate to the edges of each panel in way of the coamings. The clear profile of these openings is to be kept as small as possible. BKI - Rules for Hull - 2014
- 259. Section 17 - Hatchways B 17-11/20 Where a hatch is covered by several hatch cover panels the clear opening of the gap in between the panels shall be not wider than 50 mm. Thelabyrinthsandgapsbetweenhatchcoverpanelsshallbeconsideredasunprotectedopeningswithrespecttotherequirements of intact and damage stability calculations. Withregardtodrainageofcargoholdsandthenecessaryfire-fightingsystemreferenceismadetoRulesforMachineryInstallations, Volume III, Sections 11 and 12. Furthermore, the requirements for the carriage of dangerous goods are to be complied with. 5.2.2 Securing devices In the context of paragraph 5.2 an equivalence to 4.6 can be considered subject to: – the proof that in accordance with 1.3 load case C securing devices are not to be required and additionally – the transverse cover guides are effective up to a height hE above the cover supports. The height hE shall not be less than the greater of the following formulae: hE = 1, 75 @ [mm] hEmin = height of the face plate [mm] + 150 where e = largest distance of the cover guides from the longitudinal face plate [mm] s = total clearance [mm] with 10 < s < 40 The transverse guides and their substructure are to be dimensioned in accordance with the loads given in 1.7 acting at the position hE using the equivalent stress level Fv = ReH [N/mm2 ]. 5.3 Drainage arrangements 5.3.1 If drain channels are provided inside the line of gasket by means of a gutter bar or vertical extension of the hatch side and end coaming, drain openings are to be provided at appropriate positions of the drain channels. 5.3.2 Drain openings in hatch coamings are to be arranged with sufficient distance to areas of stress concentration (e.g. hatch corners, transitions to crane posts). 5.3.3 Drain openings are to be arranged at the ends of drain channels and are to be provided with non-return valves to prevent ingress of water from the outside. Lengths of fire hoses are not acceptable. 5.3.4Cross-joints of multi-panel covers are to be provided with efficient drainage arrangements. 5.3.5If a continuous outer steel contact between cover and ship structure is arranged, drainage from the space between the steel contact and the gasket is also to be provided for. 5.4 Tightness test, trials 5.4.1The self-tightening steel hatch coversonweather decks and within open superstructures are to be hose tested. The water pressure should not be less than 2 bar and the hose nozzle should be held at a distance of not more than 1,5 m from the hatch cover to be tested. The nozzle diameter should not be less than 12 mm. During frost periods equivalent tightness tests may be carried out to the satisfaction of the Surveyor. 5.4.2Upon completion of the hatchway cover system trials for proper functioning are to be carried out in presence of the Surveyor. BKI - Rules for Hull - 2014
- 260. B Section 17 - Hatchways17-12/20 6. Wooden hatchway covers & hatchway beams 6.1 Hatchway covers 6.1.1The thickness of woodenhatchcoversisnottobeless than60mmwhere the spacing of hatchway beams is 1,5 m. Where the beams spacing is greater or smaller than 1,5 m, the thickness of the covers is modified proportionally; however, it is not to be less than 50 mm. 6.1.2Where the 'tween deck height exceeds 2,5 m, or the deck load is greater than 1,8 t/m2 , the thickness of the hatch covers is to be increased at the rate of 12 mm per 1 m greater 'tween deck height, or per 0,72 t/m2 increased in deck load. 6.1.3The grovers for grips are not be arranged too near to the ends of the hatch covers. 6.1.4The wood used for the hatch coverings is to be of good quality, free from sap and objectionable defects, and dry. 6.1.5The ends of wood hatch covers shall be encircled by durable bands, e.g., of galvanized steel. 6.2. Hatchway beams 6.2.1General 6.2.1.1 Hatchwaybeamsmaybeconstructedeitherasslidingbeamsorasboltedbeams.Slidingbeamsarehatchwaybeams movable in the longitudinal hatchway direction, whereas bolted beams are fixed to the longitudinal coaming. 6.2.1.2 The scantlings ofpontoonhatchcoversfittedwithtarpaulinsandbatteningdevices used inlieuofhatchway beams and wooden hatch covers are to be determined as for hatchway beams. 6.2.1.3 The scantlings of pontoon hatch covers in 'tweendecks may be determined as for steel hatch covers according to 4.1. The same applies to portable beams (herfts) of 'tweendeck hatchways if they are constructed as box girders. 6.2.2Scantlings 6.2.2.1 Thesectionmodulusandthemomentofinertiaofhatchwaybeamssimplysupportedatbothendsaretobedetermined according to 6.3. For hatchway beams designed by direct calculations, 2.1 is to be observed. 6.2.2.2 The web thickness of hatchway beams is not be less than: t = 6 + [mm] tmin = 7,5 [mm] 6.2.2.3 In general, the web depth is not to be less than 150 mm. 6.2.2.4 The width of the beam face plate is to be sufficient to provide a minimum bearing surface for the hatch covers of 65 mm. 6.2.2.5 At beams which carry the ends of hatch covers the web plate is to extend 50 mm above the upper edge of the top flange, or flat bars of 50 mm in height are to be welded on the top flanges. 6.2.2.6 The upper face plates are to be extended to the extreme ends of the beams. For sliding beams which are supported on the edge of the coaming, on the deck, or on slide angles, also the lower face plates are to be extended to the ends of the beams. 6.2.2.7 At their ends the face plates are to be connected by continuous fillet welds to the webs at a length equal to 1,5 times the depth of web. 6.2.2.8 At the ends of bolted beams, which are supported by carriers of double angles, strengthened web plates are to be fitted, having a breadth of at least 180 mm. 6.2.2.9 Lightening holes or lifting holes are not to be provided within 0,5 m from either ends. BKI - Rules for Hull - 2014
- 261. Section 17 - Hatchways B 17-13/20 6.3. Moments of inertia, section moduli, shear areas 6.3.1Thesection modulusofsteelhatchwaybeamsandhatchcoverstiffenerswhichmayberegardedasbeingsimplysupported at both ends is not to be less than : W = [cm3 ] = permissible bending stress = The moment of inertia of steel hatchway beams of hatches in pos. 1 and 2 which may be regarded as being simply supported is not to be less than: I = C2 @ C3 @ a @ R3 @ pH [cm4 ] C1 = 1 + C1min = 1,0 " = ( = For R, R1, W, W1, I, I1 see Fig. 17.2 C2 = 2,82 for hatchway beams = 2,22 for hatch cover stiffeners C3 = 1 + 8"3 $ = Fig. 17.2 6.3.2 Within 0,1 R from supports the web sectional area is not to be less than : Aw = [cm2 ] 6.4 Arrangement and securing of hatchway beams 6.4.1The beam spacing is to be equal throughout a hatchway. Where the spacings are unequal, the difference is to be such that the shorter hatch covers cannot be used for the greater intervals. 6.4.2Hatchway beams are to be provided with an efficient device for locking them in their positions. Locking bolts are to have a diameter of at least 22 mm. 6.4.3The beams are to have a bearing surface of at least 75 mm. The thickness of supporting angles is not to be less than 12 mm. The connection of the support to the coaming is to be in proportion to the hatchway beams. 6.4.4The ends of the sliding beams are to be so designed that they cannot fall down when being moved along the coaming. BKI - Rules for Hull - 2014
- 262. B, C Section 17 - Hatchways17-14/20 6.4.5At the side coamings the hatchway beams are to be supported by strong steel carriers or between double angles. The carriers, or one of the two angles, are to be extended from the horizontal stiffener to the deck level, or the coaming is to be suitably strengthened on the outside by a stiffener. 7. Sealing and Securing Arrangements of Wooden and Non Self Tightening Pontoon Hatchway Covering 7.1 Twolayersoftarpaulinaretobeprovidedforhatchwaysindeckaccordingtopos.1and2andwithinopenstructures. The tarpaulins are to be approved type. 7.2 The steel hatch battens are to have a width of at least 60 mm and a thickness of at least 10 mm. 7.3 The cleats are to be spaced not more than 600 mm from centre to centre, the end cleats being arranged 150 mm from the hatchway corners, or, where the hatchway corners have large rounding, close to the rounding. 7.4 The cleats are to have a width of at least 65 mm, and are to be fastened by adequate welding. 7.5 The hatch wedges are to be made of hardwood which does not split when they are driven in. They shall have a taper of not more than 1 : 6 and shall be not less than 13 mm thick at the toes. Strong flat iron or flat channel bars are to be provided across the hatch covers over the tarpaulins; they are to be fastened at each end by screw bolts or similar means. 7.6 Where the length of the hatch covers exceeds 1,5 m, two hatch bars are to be provided for each section of hatch covers. For hatchways with large dimensions, longitudinal and cross bars are to be provided. C. Hatch Cover Coamings and Girders 1. General 1.1 Hatch coamings which are part of the longitudinal hull structure are to be designed according to Section 5. For structural members welded to coamings and for cutouts in the top of coaming sufficient fatigue strength according to Section 20 is to be verified. In case of transverse coamings of ships with large deck openings Section 5, F. is to be observed. 1.2 Coamings which are 600 mm or more in height are to be stiffened in their upper part by a horizontal stiffener. Where the unsupported height of a coaming exceeds 1,2 m additional stiffeners is to be arranged. Additional stiffeners may be dispensed with if this is justified by the ship's service and if sufficient strength is verified (e.g. in case of container ships). Longitudinal hatchway coamings are to be adequately supported by stays or brackets. Adequate safety against buckling is to be proved for longitudinal coamings which are part of the longitudinal hull structure. 1.3 Hatchway coamings which are exposed to the wash of sea are to be designed for the loads according to B. 1.4 On ships carrying cargo on deck, such as timber, coal or coke, the stays are to be spaced not more than 1,5 m apart. For containers on deck, see also Section 21, G.3.4. 1.5 Coaming plates are to extend to the lower edge of the deck beams; they are to be flanged or fitted with face bars or half-round bars. 1.6 The connection of the coamings to the deck at the hatchway corners is to be carried out with special care. For bulk carriers, see also Section 23, B.9. For rounding of hatchway corners, see also Section 7, A.3. 1.7 Forhatchwaycoamingswhicharedesignedonthebasisofstrengthcalculationsaswellasforhatchgirders,cantilevers and pillars, see Section 10. 1.8. Longitudinal hatch coamings with a length exceeding 0,1@ L are tobeprovidedwithtaperedbracketsor equivalent transitions and a corresponding substructure at both ends. At the end of the brackets they are to be connected to the deck by full penetration welds of minimum 300 mm in length. BKI - Rules for Hull - 2014
- 263. Section 17 - Hatchways C 17-15/20 2. Scantlings 2.1 Plating The thickness of weather deck hatch coamings shall not be less than the larger of the following values: t = [mm] = [mm] tmin = [mm] L need not be taken greater than 300 m tmin = 9,5 + tK [mm] for bulk carrier according to Section 23. For grab operation see also Section 23, B.9.1. 2.2 Coaming stays 2.2.1 Coaming stays are to be designed for the loads and permissible stresses according to B. 2.2.2 The section modulus of coaming stays of coamings, the height of which is hs < 1,6 m and which are to be designed for the load pA, shall not be less than : = [cm3 ] e = spacing of coaming stays [m] The effective breadth of the coaming plate shall not be larger than the effective plate width according to Section 3, F.2. Coaming stays are to be supported by appropriate substructures. Face plates may only be includedinthecalculationifanappropriatesubstructureisprovidedand welding ensures an adequate joint. 2.2.3 Web thickness at the root point shall not be less than : = [mm] = [mm] hw = web height of coaming stay at root point [m] Webs are to be connected to the decks by fillet welds on both sides with a = 0,44 @ tw. For toes of stay webs within 0,15 @ hw the throat thickness is to be increased to a = 0,7 @ tw for tw # 10 mm. For tw > 10,0 mm deep penetration double bevel welds are to be provided in this area. 2.2.4 For coaming stays, which transfer friction forces at hatch cover supports, sufficient fatigue strength according to Section 20 is to be verified. 2.3 Horizontal stiffeners The stiffeners shall be continuous at the coaming stays. For stiffeners with both ends constraint the elastic section modulus Wnet and shear area Asnet, calculated on the basis of net thickness, shall not be less than: Wnet = [cm3 ] Anet = [cm2 ] BKI - Rules for Hull - 2014
- 264. C, D Section 17 - Hatchways17-16/20 fp = ratio of plastic and elastic section modulus fpmax = = 1,16 in the absence of more precise evaluation For sniped stiffeners at coaming corners section modulus and shear area at the fixed support have to be increased by 35 %. The thickness of the coaming plate at the sniped stiffener end shall not be less than according to Section 3, D.3. Horizontal stiffeners on hatch coamings, which are part of the longitudinal hull structure, are to be designed analogously to longitudinals according to Section 9. D. Smaller Opening and Hatches 1. Miscellaneous openings in freeboard and superstructure decks 1.1 Manholesandsmallflushdeckhatchesindecksinpos.1and2orinopensuperstructuresaretobeclosedwatertight. 1.2 If not bolted watertight, they are to be of substantial steel construction with bayonet joints or screws. The covers are to be hinged or to be permanently attached to the deck by a chain. 1.3 Openingsinfreeboarddecksotherthanhatchwaysandmachineryspaceopenings,mayonlybearrangedinweathertight closed superstructures or deckhouses or in weathertight closed companionways of the same strength. 1.4 Companionways or access hatches on exposed parts of freeboard decks, on decks of closed superstructures and in special cases on the deck of deckhouses are to be of solid construction. The height of the doorway sills is to be 600 mm above decks in pos. 1 and 450 mm (hatches) and 380 mm (doors) respectively above decks in pos. 2. 1.5 The doors of the companionways are to be capable of being operated and secured from both sides. They are to be closed weathertight by rubber sealings and toggles. 1.6 Access hatchways shall have a clear width of at least 600 x 600 mm. 1.7 For special requirements for strength and securing of small hatches on the exposed fore deck, see 2. 2. Strength and securing of small hatches on the exposed fore deck 2.1 General 2.1.1 The strength of, and securing devices for, small hatches fitted on the exposed fore deck over the forward 0,25 L are to comply with the following requirements. 2.1.2 Small hatches in this context are hatches designed for access to spaces below the deck and are capable to be closed weathertight or watertight, as applicable. Their opening is normally 2,5 square meters or less. 2.1.3 Hatches designed for emergency escape need not comply with the requirements according methods A and B in 2.4.1, 2.5.3 and 2.6. 2.1.4 Securing devices of hatches designed for emergency escape are to be of a quick-acting type (e.g. one action wheel handles are provided as central locking devices for latching/unlatching of hatch cover) operable from both sides of the hatch cover. 2.2 Application For ships that are contracted for construction on or after 1st January 20041) on the exposed deck over the forward 0,25 L, applicable to: – All types of sea going ships, where the height of the exposed deck in way of the hatch is less than 0,1 L or 22 m 1) For ships contracted for construction prior to 1st January 2007 refer to IACS UR S26, para.3. BKI - Rules for Hull - 2014
- 265. Section 17 - Hatchways D 17-17/20 above the summer load waterline, whichever is the lesser. 2.3 Strength 2.3.1 Forsmallrectangularsteelhatchcovers,theplatethickness,stiffenerarrangementandscantlingsaretobein accordance with Table 17.4 and Fig. 17.3. Stiffeners, where fitted, are to be aligned with the metal-to-metal contact points, required in 2.5.1, see Fig. 17.3. Primary stiffeners are to be continuous. All stiffeners are to be welded to the inner edge stiffener, see Fig. 17.4. 2.3.2 The upper edge of the hatchway coamings is to be suitably reinforced by a horizontal section, normally not more than 170 mm to 190 mm from the upper edge of the coamings. 2.3.3 For small hatch covers of circular or similar shape, the cover plate thickness and reinforcement is to be specially considered. 2.3.4 For small hatch covers constructed of materials other than steel, the required scantlings are to provide equivalent strength. Table 17.4 - Scantlings for small steel hatch covers on the fore deck Nominal size [mm x mm] Cover plate thickness [mm] Primary stiffeners Secondary stiffeners Flat bar [mm x mm]; number 630 x 630 8 -- -- 630 x 830 8 100 x 8; 1 -- 830 x 630 8 100 x 8; 1 -- 830 x 830 8 100 x 10; 1 -- 1030 x 1030 8 120 x 12; 1 80 x 8; 2 1330 x 1330 8 150 x 12; 2 100 x 10; 2 For ships with L < 80 m the cover scantlings may be reduced by the factor : $ 0,75 2.4 Primary securing devices 2.4.1 Small hatches located on exposed fore deck subject to theapplication according to 2.2 are to be fitted with primary securing devices such that their hatch covers can be secured in place and weathertight by means of a mechanism employing any one of the following methods: – method A : butterfly nuts tightening onto forks (clamps) – method B : quick acting cleats – method C : central locking device 2.4.2 Dogs (twist tightening handles) with wedges are not acceptable. 2.5 Requirements for primary securing 2.5.1 The hatch cover is to be fitted with a gasket of elastic material. This is to be designed to allow a metal to metal contactatadesignedcompressionandtopreventover-compressionofthegasketbygreenseaforcesthatmaycausethesecuring devicestobeloosenedordislodged.Themetal-to-metalcontactsaretobearrangedclosetoeachsecuringdeviceinaccordance with Fig. 17.3 and of sufficient capacity to withstand the bearing force. 2.5.2 The primary securing method is to be designed and manufactured such that the designed compression pressure is achieved by one person without the need of any tools. 2.5.3 For a primary securing method using butterfly nuts, the forks (clamps) are to be of robust design. They are to be designed to minimize the risk of butterfly nuts being dislodged while in use; by means of curving the forks upward, a raised surface on the free end, or a similar method. The plate thickness of unstiffened steel forks is not to be less than 16 mm. An example arrangement is shown in Fig. 17.4. BKI - Rules for Hull - 2014
- 266. D, E Section 17 - Hatchways17-18/20 2.5.4 For small hatch covers located on the exposed deck forward of the foremost cargo hatch, the hinges are to be fitted such that the predominant direction of green sea will cause the cover to close, which means that the hinges are normally to be located on the fore edge. 2.5.5 On small hatches located between the main hatches, for example between Nos. 1 and 2, the hinges are to be placed on the fore edge or outboard edge, whichever is practicable for protection from green water in beam sea and bow quartering conditions. 2.6 Secondary securing device Small hatches on the fore deck are to be fitted with an independent secondary securing device e.g. by means of a sliding bolt, a hasp or a backing bar of slack fit, which is capable of keeping the hatch cover in place, even in the event that the primary securing device became loosened or dislodged. It is to be fitted on the side opposite to the hatch cover hinges. Fall arresters against accidental closing are to be provided. E. Engine and Boiler Room Hatchways 1. Deck openings 1.1 The openings above engine rooms and boiler rooms should not be larger than necessary. In way of these rooms sufficient transverse strength is to be ensured. 1.2 Engine and boiler room openings are to be well rounded at their corners, and if required, to be provided with strengthenings.unlessproperdistributionofthelongitudinalstressesisensuredbythesidewallsofsuperstructuresordeckhouses. See also Section 7, A.3. 2. Engine and boiler room casings 2.1 Engine and boiler room openings on weather decks and inside open superstructures are to be protected by casings of sufficient height. 2.2 The height of casings on the weather deck of ships with full scantling draught is to be not less than 1,8 m where L does not exceed 75 m, and not less than 2,3 m where L is 125 m or more. Intermediate values are to be determined by interpolation. 2.3 The scantlings of stiffeners, plating and covering of exposed casings are to comply with the requirements for superstructure end bulkheads and for deckhouses according to Section 16, C. 2.4 Inside open superstructures the casings are to be stiffened and plated according to Section 16, C., as for an aft end bulkhead. BKI - Rules for Hull - 2014
- 267. Section 17 - Hatchways E 17-19/20 Fig. 17.3 - Arrangement of stiffeners 2.5 The height of casings on superstructure decks is to be at least 760 mm. The thickness of their plating may be 0,5 mm less than derived from 2.3, and the stiffeners are to have the same thickness and a depth of web of 75 mm, being spaced at 750 mm. 2.6 The plate thickness of engine and boiler room casings below the freeboard deck or inside closed superstructures is to be 5 mm, and 6,5 mm in cargo holds; stiffeners are to have at least 75 mm web depth, and the same thickness as the plating, when being spaced at 750 mm. 2.7 The coaming plates are to be extended to the lower edge of the deck beams. 3. Doors in engine and boiler room casings 3.1 Thedoors incasings onexposeddecksandwithinopensuperstructuresaretobeofsteel,well stiffenedandhinged, and capable of being closed from both sides and secured weathertight by toggles and rubber sealings. Note For ships with reduced freeboard (B-minus) or tanker freeboard (A), Regulation 26 (1) of ICLL is to be observed. 3.2 The doors are to be at least of the same strength as the casing walls in which they are fitted. 3.3 The height of the doorway sills is to be 600 mm above decks in pos. 1 and 380 mm above decks in pos. 2. BKI - Rules for Hull - 2014
- 268. E Section 17 - Hatchways17-20/20 Fig. 17.4 - Example of a primary securing method BKI - Rules for Hull - 2014
- 269. Section 18 - Equipment A, B 18-1/10 Section 18 Equipment A. General 1. The equipment of anchors. chain cables, wires and ropes is to be determined from Table 18.2 in accordance with the equipment numeral Z1 or Z2, respectively. Note The anchoring equipment required by this Section is intended of temporary mooring of a vessel within a harbour or sheltered area when the vessel is awaiting berth, tide, etc. The equipment is, therefore, not designed to hold a ship off fully exposed coasts in rough weather or to stop a ship which is moving or drifting. In this condition the loads on the anchoring equipment increase to such a degree that its components may be damaged or lost owing to the high energy forces generated, particularly in large ships. The anchoring equipment required by this Section is designed to hold a ship in good holding ground in conditions such as to avoid dragging of the anchor. In poor holding ground the holding power of the anchors will be significantly reduced. The equipment numeral formula for anchoring equipment required under this Section is based on an assumed current speed of 2,5 m/sec, wind speed of 25 m/sec and a scope of chain cable between 6 and 10, the scope being the ratio between length of chain paid out and water depth. It is assumed that under normal circumstances a ship will use only one bow anchor and chain cable at a time. 2. Every ship is to be equipped with at least one anchor windlass. Windlass and chain stopper, if fitted, are to comply with Rules for Machinery Installations, Volume III, Section 14,D. For the substructures of windlasses and chain stoppers, see Section 10, B.5. For the location of windlasses on tankers, see Section 24, A.9. 3. For ships having the navigation Notation "L" (Coasting Service) affixed to their Character of Classification, the equipment may be determined as for one numeral range lower than required in accordance with the equipment numeral Z1 or Z2, respectively. 4. When determining the equipmentforshipshavingthenavigationnotation"T"(Sheltered Shallow Water Service) affixed to their Character of Classification, the provisions of Section 30, E. are to be observed. 5. When determining the equipment for tugs, Section 27, E. is to be observed. When determining the equipment of barges and pontoons, Section 31, G. is to be observed. 6. Ships built under survey of BKI and which are to have the mark a stated in their Certificate and in the Register Book must be equipped with anchors and chain cables complying with the Rules for Materials, Volume V, and having been tested on approved machines in the presence of Surveyor. 7. For ships having three or more propellers, a reduction of the weight of the bower anchors and the chain cables may be considered. B. Equipment Numeral 1. The equipment numeral Z1 for anchors and chain cables is to be calculated as follows : Z1 = D = moulded displacement [ton] (in sea water having a density of 1,025 t/m3 ) to the summer load waterline h = effective height from the summer load waterline to the top of the uppermost house BKI - Rules for Hull - 2014
- 270. B, C Section 18 - Equipment18-2/10 = a + Ghi a = distance [m], from the summer load water-line, amidships, to the upper deck at side A = area [m2 ], in profile view of the hull, superstructures and houses, having a breadth greater than B/4, above the summer load waterline within the length L and up to the height h 3hi = sum of height [m] of superstructures and deckhouses, measured on the centreline of each tier having a breadth greater than B/4. Deck sheer, if any, is to be ignored. For the lowest tier, "h" is to be measured at centreline from the upper deck or from a notional deck line where there is local discontinuity in the upper deck. Where a deckhouse having a breadth greater than B/4 is located above a deckhouse having a breadth of B/4 or less, the wide house is to be included and the narrow house ignored. Screens of bulwarks 1,5 m or more in height are to be regarded as parts of houses when determining h and A, e.g. the area shown in Fig. 18.1 as A1 is to be included in A. The height of the hatch coamings and that of any deck cargo, such as containers, may be disregarded when determining h and A. Fig. 18.1 Effective area A1 of bulwark 2. The equipment numeral Z2 for the recommended selection of ropes as well as for the determination of the design load for shipboard towing and mooring equipment and supporting hull structure is to be calculated as follows: Z2 = D = moulded displacement [t] in sea water having a density of 1,025 t/m3 to the summer load waterline h = effective height from the summer load waterline to the top of the uppermost house = a + Ehi a = distance [m], from the summer load waterline, amidships, to the upper deck at side Ehi = sum of height [m] of superstructures and deckhouses on the upper deck, measured on the centreline of each tier. Deck sheer, if any, is to be ignored. For the lowest tier, "h" is to be measured at centreline from the upper deck or from a notional deck line where there is local discontinuity in the upper deck. A = area [m2 ], in profile view of the hull, superstructures and deckhouses above the summer load waterline within the length L. Screens of bulwarks, hatch coamings and deck equipment, e.g., masts and lifting gear, as well as containers on deck have to be observed for the calculation of A. C. Anchors 1. The number of bower anchors is to be determined according to column 3 of Table 18.2. The anchors are to be connected to their chain cables and positioned on board ready for use. It is to be ensured that each anchor can be stowed in the hawse and hawse pipe in such a way that it remains firmly secured in seagoing conditions. Details have to be coordinated with the owner. Note National regulations concerning the provision of a spare anchor, stream anchor or a stern anchor may need to be observed. BKI - Rules for Hull - 2014
- 271. Section 18 - Equipment C, D 18-3/10 2. Anchors shall be of approved design. The mass of the heads of patent (ordinary stockless) anchors, including pins and fittings, is not to be less than 60% of the total mass of the anchor. 3. For stock anchors, the total mass of the anchor, including the stock, shall comply with the values in Table 18.2. The mass of the stock shall be 20 % of this total mass. 4. The mass of each individual bower anchor may vary by up to 7 % above or below the required individual mass provided that the total mass of all the bower anchors is not less than the sum of the required individual masses. 5. Where special anchors approved as "High Holding Power Anchors" are used, the anchor mass may be 75 % of the anchor mass as per Table 18.2. "High Holding Power Anchors" are anchors which are suitable for ship's use at any time and which do not require prior adjustment or special placement on the sea bed. For approval as a "High Holding Power Anchor", satisfactory tests are to be made on various types of sea bottom and the anchor is to have a holding power at least twice that of a patent anchor ("Admiralty Standard Stockless") of the same mass. The mass of anchors to be tested should be representative of the full range of sizes intended to be manufactured. The tests are to be carried out on at least two sizes of anchors in association with the chain cables appropriate to the weight. The anchors to be tested and the standard stockless anchors should be of approx. the same mass. The chain length used in the tests should be approx. 6 to 10 times the depth of water. The tests are normally to be carried out from a tug, however, alternative shore based tests (e.g. with suitable winches) may be accepted. Three tests are to be carried out for each anchor and type of bottom. The pull shall be measured by means of a dynamometer or recorded by a recording instrument. Measurements of pull based on rpm/bollard pull curve of the tug may be accepted. Testing by comparison with a previously approved HHP anchor may be accepted as a basis for approval. The maximum mass of an anchor thus approved may be 10 times the mass of the largest size of anchor tested. The dimensioning of the chain cable and of the windlass is to be based on the undiminished anchor mass according to the Tables. 6. Where stern anchor equipment is fitted, such equipment is to comply in all respects with the rules for anchor equipment. The mass of each stern anchor shall be at least 35 % of that of the bower anchors. The diameter of the chain cables and the chain length are to be determined from the Tables in accordance with the anchor mass. Where a stern anchor windlass is fitted the requirements of Rules for Machinery Installations, Volume III, Section 14, are to be observed. 7. Where a steel wire rope is to be used for the stern anchor instead of a chain cable the following has to be observed: 7.1 The steel wire rope shall at least be as long as the required chain cable. The strength of the steel wire rope shall at least be of the value for the required chain of grade K1. 7.2 Between anchor and steel wire rope a shot of 12,5 m in length or of the distance between stowed anchor and windlass shall be provided. The smaller length has to be taken. 7.3 A cable winch must be provided according to the requirements for windlasses in Rules for Machinery Installations, Volume III, Section 14, B. D. Chain Cables 1. The chain cable diameters given in the Tables apply to chain cables made of chain cable materials specified in the requirements of Rules for Materials, Volume V, for the following grades: Grade K 1 (ordinary quality) Grade K 2 (special quality) Grade K 3 (extra special quality) 2. Grade K 1 material used for chain cables in conjunction with "High Holding Power Anchors" shall have a tensile BKI - Rules for Hull - 2014
- 272. D, E Section 18 - Equipment18-4/10 strength Rm of not less than 400 N/mm2 . 3. Grade K 2 and K 3 chain cables shall be post production quenched and tempered and purchased from recognized manufacturers only. 4. The total length of chain given in the Table 18.2 is to be divided in approximately equal parts between the two bower anchors. 5. Either stud link or short link chain cables may be used for stream anchors. 6. For connection of the anchor with the chain cable approved Kenter-type anchor shackles may be chosen in lieu of the common Dee-shackles. A forerunner with swivel is to be fitted between anchor and chain cable. In lieu of a forerunner with swivel an approved swivel shackle may be used. However, swivel shackles are not to be connected to the anchor shank unless specially approved. A sufficient number of suitable spare shackles are to be kept on board to facilitate fitting of the spare anchor at any time. On owner's request the swivel shackle may be dispensed with. 7. The attachment of the inboard ends of the chain cables to the ship's structure is to be provided with a mean suitable to permit, in case of emergency, an easy slipping of the chain cables to sea operable from an accessible position outside the chain locker. The inboard ends of the chain cables are to be secured to the structures by a fastening able to withstand a force not less than 15% nor more than 30% of the rated breaking load of the chain cable. E. Chain Locker 1. The chain locker is to be of capacity and depth adequate to provide an easy direct lead of the cables through the chain pipes and self-stowing of the cables. The minimum required stowage capacity without mud box for the two bow anchor chains is as follows: [m3 ] d = chain diameter [mm] according to Table 18.2 R = total length of stud link chain cable according to Table 18.2 The total stowage capacity is to be distributed on two chain lockers of equal size for the port and starboard chain cables. The shape of the base areas shall as far as possible be quadratic with a maximum edge length of 33 d. As an alternative, circular base areas may be selected, the diameter of which shall not exceed 30 – 35 d. Above the stowage of each chain locker sufficient free depth is to be provided 2. The chain locker boundaries and their access openings are to be watertight to prevent flooding of essential installation or equipment are aranged, in order to not affect the proper operation of the ship after accidental flooding of the chain locker. 2.1 Special requirements to minimize the ingress of water 2.1.1 Spurling pipes and cable lockers are to be watertight up to the weather deck. 2.1.2Where means of access is provided, it is to be closed by a substantial cover and secured by closely spaced bolts. 2.1.3 Spurling pipes through which anchor cables are led are to be provided with permanently attached closing appliances to minimize water ingress. 3. Adequate drainage facilities of the chain locker are to be provided. 4. Where the chain locker boundaries are also tank boundaries their scantlings of stiffeners and plating are to be determined as for tanks in accordance with Section 12. Where this is not the case the plate thickness is to be determined as for t2 and the section modulus as for W2 in accordance with Section 12, B.2. and B.3. respectively. The distance from the load centre to the top of the chain locker pipe is to be BKI - Rules for Hull - 2014
- 273. Section 18 - Equipment F 18-5/10 taken for calculating the load. 5. For th e location of chain lockers on tankers Section 24, A.9 is to be observed. F. Mooring Equipment 1. Ropes 1.1 The following items 1.2 to 1.6 and the Tables 18.1 and 18.2 for tow lines and mooring ropes are recommendations only, a compliance with which is not a condition of Class. 1.2 For tow lines and mooring lines, steel wire ropes as well as fibre ropes made of natural or synthetic fibres or wire ropes consisting of steel wire and fibre cores may be used. The breaking loads 1) specified in Table 18.2 are valid for wire ropes and ropes of natural fibre (Manila) only. Where ropes of synthetic fibre are used, the breaking load is to be increased above the table values. The extent of increase depends on the material quality. The required diameters of synthetic fibre ropes used in lieu of steel wire ropes may be taken from Table 18.1. Table 18.1 - Wire/ fibre ropes diameter Steel wire ropes 1) Synthetic wire ropes Poly- amide2) Fibre ropes Polyamide Polyester Polypropylene dia. [mm] dia. [mm] dia. [mm] dia. [mm] dia. [mm] 12 13 14 16 18 20 22 24 26 28 32 36 40 30 30 32 32 36 40 44 48 56 60 68 72 72 30 32 36 40 44 48 48 52 60 64 72 80 88 30 32 36 40 44 48 48 52 60 64 72 80 88 30 32 36 40 44 48 52 56 64 72 80 88 96 1) According to DIN 3068 or equivalent 2) Regular laid ropes of refined polyamide monofilaments and filament fibres. 1.3 Where the stream anchor is used in conjunction with a rope, this is to be a steel wire rope. 1.4 Wire ropes shall be of the following type: – 6 x 24 wires with 7 fibre cores for breaking loads of up to 500 kN type: Standard – 6 x 36 wires with 1 fibre core for breaking loads of more than 500 kN type: Standard. Where wire ropes are stored on mooring winch drums, steel cored wire ropes may be used e.g. : – 6 x 19 wires with 1 steel core 1) The term "Breaking Load" used throughout this Section means the "Nominal breaking load". BKI - Rules for Hull - 2014
- 274. F Section 18 - Equipment18-6/10 type: Seale – 6 x 36 wires with 1 steel core type: Warrington-Seale. 1.5 Regardless of the breaking load, recommended in Table 18.2, the diameter of fibre ropes should not be less than 20 mm. 1.6 The length of the individual mooring ropes may be up to 7 % less than that given in the table provided that the total length of all the wires and ropes is not less than the sum of the required individual lengths. Where mooring winches on large ships are located on one side of the ship, the lengths of mooring ropes should be increased accordingly. For individual mooring lines with a breaking load above 500 kN the following alternatives may be applied: .1 The breaking load of the individual mooring lines specified in Table 18.2 may be reduced with corresponding increase of the number of mooring lines, provided that the total breaking load of all lines aboard ship is not less than the rule value as per Table 18.2. No mooring line, however, should have a breaking load of less than 500 kN. .2 The number of mooring lines may be reduced with corresponding increase of the breaking load of the individual mooring lines, provided that the total breaking load of all lines aboard ship is not less than the rule value specified in Table 18.2, however, the number of lines should not be less than 6. 2. Shipboard fittings (mooring bollards and bitts, fairleads, stand rollers, chocks) The selection of shipboard fittings is to be made by the shipyard in accordance with an industry standard (e.g. ISO 3913 Shipbuilding Welded Steel Bollards) accepted by BKI. When the shipboard fitting is not selected froman accepted industry standard, the design load used to assess its strength and its attachment to the ship is to be in accordance with 3. 2.1 Arrangement Shipboard fittings for mooring are to be located on longitudinals, beams and/or girders, which are part of the deck construction so as to facilitate efficient distribution of the mooring load. Other arrangements may be accepted (for Panama chocks, etc.) provided the strength is confirmed adequate for the service. 2.2 Safe working load (SWLGL) 1) The safe working load for fittings is to be calculated as follows: FD = design load per 3.1. 2) The SWLGL of each shipboard fitting is to be marked (by weld bead or equivalent) on the deck fittings used for mooring. 3) The above requirements on SWLGL apply for a single post basis (no more than one turn of one cable). 4) The towing and mooring arrangements plan mentioned in H. is to define the method of use of mooring lines. 3. Supporting hull structure for mooring equipment Strength calculations for supporting hull structures of mooring equipment are to be based on net thicknesses. tk = corrosion addition according to 4. 3.1 Load considerations 1) Unless greater safe working load (SWLGL) of shipboard fittings is specified by the applicant, the design load applied to shipboard fittings and supporting hull structures is to be 1,25 times the breaking strength of the mooring line according to Table 18.2 for the equipment numeral Z2. When ropes with increased breaking strength are used, the design load needs not to be in excess of 1,25 times the breaking strength of the mooring line according to Table 18.2 for the equipment numeral Z2. This is not applicable, if the breaking strength of the ropes is increased in accordance with 1.6. BKI - Rules for Hull - 2014
- 275. Section 18 - Equipment F 18-7/10 2) The minimum design load applied to supporting hull structures for winches, etc. is to be the design load acc. to (1). For capstans, the minimum design load is to be 1,25 times the maximum hauling-in force. 3) The design load is to be applied through the mooring line according to the arrangement shown on the towing and mooring arrangements plan, see Fig. 18.2. 4) When a specific SWLGL, that is greater than required in 2.2 (1), is applied for a fitting at the request of the applicant, the fitting and the supporting hull structure have to be designed using the requested SWLGL times 1,875 as design load. Fig. 18.2 Application of design loads 5) The acting point of the mooring force on shipboard fittings is to be taken at the attachment point of a mooring line or at a change in its direction. For bollards, the acting point of the design load is to be taken at least equivalent to the diameter of the pipe above deck level. Special designs have to be evaluated individually. 3.2 Allowable stresses Normal stress: FN < ReH Shear stress: J 0,6 ReH Equivalent stress: FV ReH ReH = Nominal upper yield point of the material used [N/mm2 ] acc. Section 2, B.2. 4. Corrosion addition The total corrosion addition, tk, in mm, for both sides of the hull supporting structure is not to be less than the following values: – Ships covered by CSR for bulk carriers and CSR for double hull oil tankers: Total corrosion additions defined in these rules – Other ships: 2,0 mm in general and 1,0 mm in dry spaces 5. Equipment for mooring at single point moorings 5. 1 Upon request from the owner, BKI is prepared to certify that the vessel is specially fitted for compliance with Sections 2.1, 4.2 and 6. of the "Standards for equipment employed in the mooring of ships at single point moorings" published by the Oil Companies International Marine Forum (OCIMF), 1978. 5. 2 The certificate may be issued if .1 plans showing the equipment and the arrangement as well as necessary substructures are submitted for approval; .2 the chain stopper, Smith bracket, or other device for securing the chafing chain to the ship and the structure to which it is attached are capable of withstanding a load not less than the breaking strength of the chain corresponding to the size of the ship as given in Section 6 of the standards stipulated in 5.1 above and calculations to demonstrate this capability are submitted; .3 the chain bearing surface of the bow fairleads described in 6.1 of the standard stipulated in 3.5.1 above have a diameter at least seven times that of the associated chain; .4 the installation on board the ship is surveyed by BKI’s Surveyor. BKI - Rules for Hull - 2014
- 276. G Section 18 - Equipment18-8/10 G. Towing Equipment 1. Shipboard fittings 1.1 Arrangement and strength Shipboard fittings for towing are to be located on longitudinals, beams and/or girders, which are part of the deck construction so as to facilitate efficient distribution of the towing load. Other arrangements may be accepted (for Panama chocks, etc.) provided the strength is confirmed adequate for the intended service. The strength of shipboard fittings used for ordinary towing operations (not emergency towing) at bow, sides and stern and their supporting hull structures are to be determined on the basis of 1.1.1 and 1.1.2. Strength calculations are to be based on net thicknesses tnet = t – tk tk = corrosion addition, see F.4. 1.1.1 Load considerations Unless greater safe working load (SWL) of shipboard fittings is specified by the applicant, the minimum design load to be used is the following value of (1) or (2), whichever is applicable: 1) for normal towing operations (e.g., in harbour) using fittings at bow, sides and stern, 1,875 times the intended maximum towing load (e.g. static bollard pull) as indicated on the towing and mooring arrangements plan. If the intended maximum towing load is not specified by the applicant, the nominal breaking strength of the corresponding mooring lines according to Table 18.2 for the equipment numeral Z2 is to be applied. 2) for other towing service using the forward main towing fittings, in general arranged on forecastle deck at the vessel's centreline, the nominal breaking strength of the tow line according to Table 18.2 for the equipment numeral Z2. 3) The design load is to be applied through the tow line according to the arrangement shown on the towing and mooring arrangements plan, see Fig. 18.2. For bollards, the acting point of the design load is to be taken at least equivalent to the diameter of the pipe above deck level. Special designs have to be evaluated individually. 4) When a specific SWLGL, that is greater than required in 1.2, is applied for a fitting at the request of the applicant, the fitting and the supporting hull structure have to be designed using the requested SWLGL times 1,875 as design load. 1.1.2 Allowable stresses Normal stress: FN < ReH Shear stress: J < 0,6 ReH Equivalent stress: FV < ReH ReH = Nominal upper yield point of the material used [N/mm2 ] acc. Section 2, B.2. 1.2 Safe working load (SWL) 1) The safe working load for a shipboard fitting used for normal towing operations is not to exceed the following value: FD = design load per 1.1.1(1) 2) The safe working load for a shipboard fitting used for other towing service (i.e., for the main towing fittings) is not to exceed the following value: FD = design load per 1.1.1(2). 3) For chocks and bollards of which the strength shall comply with Panama Canal Regulations, the safe working load is not to exceed the following value: BKI - Rules for Hull - 2014
- 277. Section 18 - Equipment G, H 18-9/10 FD = design load according to Panama Canal Regulations. 4) The SWLGL of each shipboard fitting is to be marked (by weld bead or equivalent) on the deck fittings used for towing. For fittings, which are used for different mooring or towing operations, the greater of the safe working loads SWLGL is to be marked. 5) The above requirements on SWLGL apply for a single post basis (no more than one turn of one cable). 6) The towing and mooring arrangements plan mentioned in H. is to define the method of use of towing lines. H. Towing and Mooring Arrangements Plan The SWLGL for the intended use for each shipboard fitting is to be noted in the towing and mooring arrangements plan available on board for the guidance of the Master. Information provided on the plan is to include in respect of each shipboard fitting: – location on the ship – fitting type – SWLGL – purpose (mooring / normal towing operations / other towing services); and – manner of applying towing or mooring line load including limiting fleet angles. This information is to be incorporated into the pilot card in order to provide the pilot proper information on harbour/escorting operations. BKI - Rules for Hull - 2014
- 278. H Section 18 - Equipment18-10/10 Table 18.2 - Anchor, Chain Cables and Ropes No. for Reg. Equipment numeral Z1 or Z2 Stockless anchor Stud link chain cables Recommended ropes Bower anchor Stream anchor Bower anchors Stream wire or chain for stream anchor Towline Mooring ropes Num- ber 1) Mass per anchor Total length Diameter Length Br. load2) Length Br. load2) Num- ber Length Br. load2) d1 d2 d3 [kg] [m] [mm] [mm] [mm] [m] [kN] [m] [kN] [m] [kN] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 up to 50 50 - 70 70 - 90 90 - 110 110 - 130 130 - 150 150 - 175 175 - 205 205 - 240 240 - 280 280 - 320 320 - 360 360 - 400 400 - 450 450 - 500 500 - 550 550 - 600 600 - 660 660 - 720 720 - 780 780 - 840 840 - 910 910 - 980 980 - 1060 1060 - 1140 1140 - 1220 1220 - 1300 1300 - 1390 1390 - 1480 1480 - 1570 1570 - 1670 1670 - 1790 1790 - 1930 1930 - 2080 2080 - 2230 2230 - 2380 2380 - 2530 2530 - 2700 2700 - 2870 2870 - 3040 3040 - 3210 3210 - 3400 3400 - 3600 3600 - 3800 3800 - 4000 4000 - 4200 4200 - 4400 4400 - 4600 4600 - 4800 4800 - 5000 5000 - 5200 5200 - 5500 5500 - 5800 5800 - 6100 6100 - 6500 6500 - 6900 6900 - 7400 7400 - 7900 7900 - 8400 8400 - 8900 8900 - 9400 9400 - 10000 10000 - 10700 10700 - 11500 11500 - 12400 12400 - 13400 13400 - 14600 14600 - 16000 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 120 180 240 300 360 420 480 570 660 780 900 1020 1140 1290 1440 1590 1740 1920 2100 2280 2460 2640 2850 3060 3300 3540 3780 4050 4320 4590 4890 5250 5610 6000 6450 6900 7350 7800 8300 8700 9300 9900 10500 11100 11700 12300 12900 13500 14100 14700 15400 16100 16900 17800 18800 20000 21500 23000 24500 26000 27500 29000 31000 33000 35500 38500 42000 46000 40 60 80 100 120 140 165 190 165 220 220 247,5 247,5 275 275 302,5 302,5 330 357,5 357,5 385 385 412,5 412,5 440 440 440 467,5 467,5 467,5 495 495 495 522,5 522,5 522,5 550 550 550 577,5 577,5 577,5 605 605 605 632,5 632,5 632,5 660 660 660 687,5 687,5 687,5 715 715 715 742,5 742,5 742,5 742,5 742,5 742,5 770 770 770 770 770 770 770 770 770 770 770 770 770 12,5 14 16 17,5 19 20,5 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 73 76 78 81 84 87 90 92 95 97 100 102 105 107 111 114 117 120 122 124 127 130 132 12,5 12,5 14 16 17,5 17,5 19 20,5 22 24 26 28 30 32 34 34 36 38 40 42 44 46 48 50 50 52 54 56 58 60 62 64 66 68 70 73 76 78 81 84 84 87 90 92 95 97 100 102 105 107 111 111 114 117 120 124 127 132 137 142 147 152 12,5 12,5 14 16 17,5 17,5 19 20,5 20,5 22 24 24 26 28 30 30 32 34 36 36 38 40 42 44 46 46 48 50 50 52 54 56 58 60 62 64 66 68 70 73 76 78 78 81 84 87 87 90 92 95 97 97 100 102 107 111 114 117 122 127 132 132 137 142 147 152 157 162 80 80 85 85 90 90 90 90 65 65 75 80 90 100 110 120 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 190 190 190 190 190 190 190 190 200 200 200 200 200 200 220 220 220 220 220 240 240 240 260 260 260 280 280 280 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 100 100 100 100 100 100 100 110 130 150 175 200 225 250 275 305 340 370 405 440 480 520 560 600 645 690 740 785 835 890 940 1025 1110 1170 1260 1355 1455 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 1470 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 6 7 7 7 7 7 8 8 8 9 9 9 10 11 11 12 13 14 15 16 17 18 19 21 80 80 100 110 110 120 120 120 120 120 140 140 140 140 140 160 160 160 160 170 170 170 170 180 180 180 180 180 180 190 190 190 190 190 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 35 35 40 40 45 50 55 60 65 70 80 85 95 100 110 120 130 145 160 170 185 200 215 230 250 270 285 305 325 325 335 350 375 400 425 450 480 480 490 500 520 555 590 620 650 650 660 670 680 685 685 695 705 705 715 725 725 725 735 735 735 735 735 735 735 735 735 735 d1 = Chain diameter Grade K 1 (Ordinary quality) d2 = Chain diameter Grade K 2 (Special quality) d3 = Chain diameter Grade K 3 (Extra special quality) See also D 1) see C.1. 2) see F.1.2 BKI - Rules for Hull - 2014
- 279. Section 19 - Welded Joints A 19-1/20 Section 19 Welded Joints Preface The content of this Section is to a large extent identical to that of Rules for Welding Volume VI, Section 12, G. Because of the reissues of Section 12, G. referred to and this Section at different times, some temporary divergences may arise and in such circumstances the more recent Rules shall take precedence. A. General 1. Information contained in manufacturing documents 1.1 The shapes and dimensions of welds and, where proof by calculation is supplied, the requirements applicable to welded joints (the weld quality grade, detail category) are to be stated in drawings and other manufacturing documents (parts lists, welding and inspection schedules). In special cases, e.g. where special materials are concerned, the documents shall also state the welding method, the welding consumables used, heat input and control, the weld build-up and any post-weld treatment which may be required. 1.2 Symbols andsigns used to identify welded joints shall be explained if they depart fromthe symbols anddefinitions contained in the relevant standards (e.g. DIN standards). Where the weld preparation (together with approved methods of welding) conforms both to normal shipbuilding practice and to these Rules and recognized standards, where applicable, no special description is needed. 2. Materials, weldability 2.1 Onlybasematerialsof provenweldability(seeSection 2)maybeusedforweldedstructures.Anyapprovalconditions of the steel or of the procedure qualification tests and the steelmaker's recommendations are to be observed. 2.2 Fornormalstrengthhullstructuralsteelsgrades A,B,DandEwhichhavebeentestedbyBKI,weldabilitynormally is considered to have been proven. The suitability of these base materials for high efficiency welding processes with high heat input shall be verified. 2.3 Higher strength hull structural steels grade AH/DH/EH/FH which have been approved by BKI in accordance with therelevantrequirementsofRules forMaterials, Volume V, have hadtheirweldabilityexaminedand,providedtheirhandling is in accordance with normal shipbuilding practice, may be considered to be proven. The suitability of these base materials for high efficiency welding processes with high heat input shall be verified. 2.4 High strength (quenched and tempered) fine grain structural steels, low temperature steels, stainless and other (alloyed) structural steels require special approval by BKI. Proof of weldability of the respective steel is to be presented in connection with the welding procedure and welding consumables. 2.5 CaststeelandforgedpartsrequiretestingbyBKI.Forcastingsintendedtobeusedforweldedshipbuildingstructures the maximum permissible values of the chemical composition according to Rules for Material Vol. V, Section 7, B.4 and Table 7.1 have to be observed. 2.6 AluminiumalloysrequiretestingbyBKI.Proofoftheirweldabilityshallbepresentedinconnectionwiththewelding procedure and welding consumables. 2.7 Welding consumables used are to be suitable for the parent metal to be welded and are to be approved by BKI. 3. Manufacture and testing 3.1 The manufacture of welded structural components may only be carried out in workshops or plants that have been approved. The requirements that have to be observed in connection with the fabrication of welded joints are laid down in the Rules for Welding, Volume VI. BKI - Rules for Hull - 2014
- 280. A, B Section 19 - Welded Joints19-2/20 3.2 The weld quality grade of welded joints without proof by calculation (see 1.1) depends on the significance of the welded joint for the total structure and on its location in the structural element (location to the main stress direction) and on its stressing. For details concerning the type, scope and manner of testing, see Rules for Welding, Volume VI, Section 12, I. Where proof of fatigue strength is required, in addition the requirements of Section 20 apply. B. Design 1. General design principles 1.1 During the design stage welded joints are to be planned such as to be accessible during fabrication, to be located in the best possible position for welding and to permit the proper welding sequence to be followed. 1.2 Both the welded joints and the sequence of welding involved are to be so planned as to enable residual welding stressestobekepttoaminimuminorderthatnoexcessive deformation occurs.Weldedjointsshouldnotbeoverdimensioned, see also 3.3.3. 1.3 When planning welded joints, it shall first be established that the type and grade of weld envisaged, such as full root weld penetration in the case of HV or DHV (K) weld seams, can in fact be perfectly executed under the conditions set by the limitations of the manufacturing process involved. If this is not the case, a simpler type of weld seam shall be selected and its possibly lower load bearing capacity taken into account when dimensioning the component. 1.4 Highly stressed welded joints which, therefore, are generally subject to examination are to be so designed that the most suitable method of testing for faults can be used (radiography, ultrasonic, surface crack testing methods) in order that a reliable examination may be carried out. 1.5 Special characteristics peculiar to the material, such as the lower strength values of rolled material in the thickness direction (see 2.5.1) or the softening of cold worked aluminium alloys as a result of welding, are factors which have to be taken into account when designing welded joints. Clad plates where the efficiency of the bond between the base and the clad materialisprovedmaygenerallybetreatedassolidplates(uptomediumplatethicknesseswheremainlyfilletweldconnections are used). 1.6 In cases where different types of material are paired and operate in sea water or any other electrolytic medium, for example welded joints made between unalloyed carbon steels and stainless steels in the wear-resistant cladding in rudder nozzles or in the cladding of rudder shafts, the resulting differencesinpotentialgreatlyincreasethesusceptibilitytocorrosion and shall therefore be given special attention. Where possible, such welds are to be positioned in locations less subject to theriskofcorrosion(suchasontheoutsideoftanks)orspecialprotectivecounter-measuresaretobetaken(suchastheprovision of a protective coating or cathodic protection). 2. Design details 2.1 Stress flow, transitions 2.1.1All welded joints on primary supporting members shall be designed to provide as smooth a stress profile as possible with no major internal or external notches, no discontinuities in rigidity and no obstructions to strains, see Section 3, H. 2.1.2This applies in analogous manner to the welding of subordinate components on to primary supporting members whose exposed plate or flange edges should, as faras possible, be kept free fromnotch effects due to welded attachments. Regarding theinadmissibilityofweldmentstotheupperedgeofthesheerstrake,seeSection6,C.3.4. Thisappliessimilarlytoweldments to the upper edge of continuous hatchway side coamings. 2.1.3Buttjointsinlongorextensivecontinuousstructuressuchasbilgekeels,fenders,cranerails,slopcoamings,etc.attached to primary structural members are therefore to be welded over their entire cross-section. 2.1.4Wherever possible, joints (especially site joints) in girders and sections shall not be located in areas of high bending stress. Joints at the knuckle of flanges are to be avoided. 2.1.5The transition between differing component dimensionsshallbesmoothand gradual. Where the depth of web of girders or sections differs, the flanges or bulbs are to be bevelled and the web slit and expanded or pressed together to equalize the depths of the members. The length of the transition should be at least equal twice the difference in depth. BKI - Rules for Hull - 2014
- 281. Section 19 - Welded Joints B 19-3/20 2.1.6Where the plate thickness differs at joints perpendicularly to the direction of the main stress, differences in thickness greater than 3 mm shall be accommodated by bevelling the proud edge in the manner shown in Fig. 19.1 at a ratio of at least 1 : 3 or according to the notch category. Differences in thickness of 3 mm or less may be accommodated within the weld. 2.1.7For the welding on of plates orotherrelatively thin-walled elements, steel castings and forgings should be appropriately tapered or provided with integrally cast or forged welding flanges in accordance with Fig. 19.2. Fig. 19.1 Accommodation of differences of thickness Fig. 19.2 Welding flanges on steel castings or forgings 2.1.8For the connection of shaft brackets to the boss and shell plating, see 4.3 and Section 13, D.2.; for the connection of horizontal coupling flanges to the rudder body, see 4.4 For the required thickened rudderstock collar required with build-up welds and for the connection of the coupling flange, see 2.7 and Section 14, D.2.4. The joint between the rudder-stock and the coupling flange are to be connected by full penetration weld. 2.2 Local clustering of welds, minimum spacing 2.2.1 The local clustering of welds and short distances between welds are to be avoided. Adjacent butt welds should be separated from each other by a distance of at least: 50 mm + 4 × plate thickness. Fillet welds should be separated from each other and from butt welds by a distance of at least: 30 mm + 2 × plate thickness. Thewidthofreplacedorinsertedplates(strips)should,however,beatleast300mmortentimestheplatethickness,whichever is the greater. 2.2.2Reinforcing plates, welding flanges, mountings and similar components socket-welded into plating should be of the following minimum size: Dmin = D = diameter of round or length of side of angular weldments [mm] t = plating thickness [mm]. The corner radii of angular socket weldments should be 5t [mm] but at least 50 mm. Alternatively the ”longitudinal seams” are to extend beyond the ”transverse seams”. Socket weldments are to be fully welded to the surrounding plating. Regarding the increase of stress due to different thickness of plates see also Section 20, B.1.3. 2.3 Welding cut-outs 2.3.1 Welding cut-outs for the (later) execution of butt or fillet welds following the positioning of transverse members should be rounded (minimum radius 25 mm or twice the plate thickness, whichever is the greater) and should be shaped to provide a smooth transition on the adjoining surface as shown in Fig. 19.3 (especially necessary where the loading is mainly dynamic). 2.3.2 Where the welds are completed prior to the positioning of the crossing members, no welding cut-outs are needed. Any weld reinforcements present are to be machined off prior to the location of the crossing members or these members are to have suitable cut-outs. 2.4 Local reinforcements, doubling plates 2.4.1Where plating (including girder plates and tube walls) are subjected locally to increased stresses, thicker plates should be used wherever possible in preference todoubling plates. Bearing bushes, hubs etc. shall invariably take the formof thicker BKI - Rules for Hull - 2014
- 282. B Section 19 - Welded Joints19-4/20 sections welded into the plating, see 2.2.2. 2.4.2Where doublings cannot be avoided, the thickness of the doubling plates should not exceed twice the plating thickness. Doubling plates whose width is greater than approximately 30 times their thickness shall be slot welded to the underlying plating in accordance with 3.3.11 at intervals not exceeding 30 times the thickness of the doubling plate. 2.4.3Along their (longitudinal) edges, doubling plates shall be continuously fillet welded with a throat thickness "a" of 0,3 x the doubling plate thickness. At the ends of doubling plates, the throat thickness "a" at the end faces shall be increased to 0,5 x the doubling plate thickness but shall not exceed the plating thickness, see Fig. 19.4. The welded transition at the end faces of the doubling plates to the plating should form with the latter an angle of 45E or less. Fig. 19.3 Welding cut-outs Fig. 19.4 Welding at the ends of doubling plates 2.4.4Where proof of fatigue strength is required (see Section 20), the configuration of the end of the doubling plate shall conform to the selected detail category. 2.4.5Doubling plates are not permitted in tanks for flammable liquids. 2.5 Intersecting members, stress in the thickness direction 2.5.1Where, in the case of intersecting members, plates or other rolled products are stressed in the thickness direction by shrinking stresses due to the welding and/or applied loads, suitable measures shall be taken in the design and fabrication of the structures to prevent lamellar tearing (stratified fractures) due to the anisotropy of the rolled products. 2.5.2Such measures include the use of suitable weld shapes with a minimum weld volume and a welding sequence designed to reduce transverse shrinkage. Other measures are the distribution of the stresses over a larger area of the plate surface by using a build-up weld or the joining together of several "fibres" of members stressed in the thickness direction as exemplified by the deck stringer/sheer strake joint shown in Fig. 19.12. 2.5.3 In case of very severe stresses in the thickness direction due, for example, to the aggregate effect of the shrinkage stressesofbulkysingleordouble-bevelbuttweldsplushighappliedloads,plateswithguaranteedthroughthicknessproperties (extrahigh-puritymaterialandguaranteedminimumreductions inarea oftensile testspecimenstakeninthicknessdirection)1) are to be used. 2.6 Welding of cold formed sections, bending radii 2.6.1 Whereverpossible,weldingshouldbeavoidedatthecoldformedsectionswithmorethan5%permanent elongation2) and in the adjacent areas of structural steels with a tendency towards strain ageing. 1) See Rules for Materials, Vol. V, Section 4, I. 2) Elongation g in the outer tensile-stressed zone , = r = inner bending radius [mm] t = plate thickness [mm] BKI - Rules for Hull - 2014
- 283. Section 19 - Welded Joints B 19-5/20 2.6.2 Welding may be performed at the cold formed sections and adjacent areas of hull structural steels and comparable structural steels (e.g. those in quality groups S...J... and S...K... to DIN EN 10025) provided that the minimum bending radii are not less than those specified in Table 19.1. Table 19.1 - Minimum inner bending radius r Plate thickness t Minimum inner bending radius r up to 4 mm up to 8 mm up to 12 mm up to 24 mm over 24 mm 1,0 × t 1,5 × t 2,0 × t 3,0 × t 5,0 × t Note : The bending capacity of the material may necessitate a larger bending radius. 2.6.3For other steels and other materials, where applicable, the necessary minimum bending radius shall, in case of doubt, be established by test. Proof of adequate toughness after welding may be stipulated for steels with minimum nominal upper yield point of more than 355 N/mm2 and plate thicknesses of 30 mmand above which have undergone cold forming resulting in 2% or more permanent elongation. 2.7 Build - up welds on rudderstocks and pintles 2.7.1Wear resistance and/or corrosion resistant build-up welds on the bearing surfaces of rudderstocks, pintles etc. shall be applied to a thickened collar exceeding by at least 20 mm the diameter of the adjoining part of the shaft. 2.7.2Whereathickenedcollarisimpossiblefordesignreasons, the build-upweldmaybeappliedtothesmoothshaftprovided that relief-turning in accordance with 2.7.3 is possible (leaving an adequate residual diameter). 2.7.3After welding, the transition areas between the welded and non-welded portions of the shaft shall be relief-turned with large radii, as shown in Fig. 19.5, to remove any base material whose structure close to the concave groove has been altered by the welding operation and in order to effect the physical separation of geometrical and metallurgical "notches". Fig. 19.5Build-up welds applied to rudderstocks and Pintles 3. Weld shapes and dimensions 3.1 Butt joints 3.1.1Depending on the plate thickness, the welding method and the welding position, butt joints shall be of the square, V or double-V shape conforming to the relevant standards (e.g. EN 22553/ISO 2533, ISO 9692-1, -2, -3 or -4). Where other weld shapes are applied, these are to be specially described in the drawings. Weld shapes for special welding processes such as single-side or electrogas welding shall have been tested and approved in the context of a welding procedure test. 3.1.2Asamatterofprinciple,therearsidesofbuttjointsshallbegroovedandweldedwithatleastonecappingpass.Exceptions to this rule, as in the case of submerged-arc welding or the welding processes mentioned in 3.1.1, require to be tested and approved in connection with a welding procedure test. The effective weld thickness shall be deemed to be the plate thickness, or, where the plate thicknesses differ, the lesser plate thickness. Where proof of fatigue strength is required (see Section 20), the detail category depends on the execution (quality) of the weld. 3.1.3Where the aforementioned conditions cannot be met, e.g. where the welds are accessible from one side only, the joints BKI - Rules for Hull - 2014
- 284. B Section 19 - Welded Joints19-6/20 shall be executed as lesser bevelled welds with an open root and an attached or an integrally machined or cast, permanent weld pool support (backing) as shown in Fig..19.63) . Fig. 19.6Single-side welds with permanent weld pool support (backings) 3.1.4TheweldshapesillustratedinFig.19.7shallbeusedforcladplates.Theseweldshapesshallbeusedinanalogousmanner for joining clad plates to (unalloyed and low alloyed) hull structural steels. Fig. 19.7 Weld shapes for welding of clad plates 3.2 Corner, T and double-T (cruciform) joints 3.2.1Corner,Tanddouble-T(cruciform)jointswithcompleteunionoftheabuttingplatesshallbemadeassingleordouble-bevel welds with a minimum root face and adequate air gap, as shown in Fig. 19.8, and with grooving of the root and capping from the opposite side. Theeffectiveweldthicknessshallbeassumedasthethicknessofthe abuttingplate.Whereproofoffatiguestrengthisrequired (see Section 20), the detail category depends on the execution (quality) of the weld. 3) On special consideration, different combination of welding angle and gap may be approved. BKI - Rules for Hull - 2014
- 285. Section 19 - Welded Joints B 19-7/20 Fig. 19.8 - Single and double-bevel welds with full root penetration 3.2.2Corner, T and double-T (cruciform) joints with a defined incomplete root penetration, as shown in Fig. 19.9, shall be made as single or double-bevel welds, as described in 3.2.1, with a back-up weld but without grooving of the root. Theeffectiveweldthicknessmaybeassumedasthethickness ofthe abutting plate t, where fis the incompleterootpenetration of 0,2 t with a maximum of 3 mm, which is to be balanced by equally sized double fillet welds on each side. Where proof of fatigue strength is required (see Section 20), these welds are to be assigned to type D1. 3.2.3Corner, T and double-T (cruciform) joints with both an unwelded root face c and a defined incomplete root penetration f shall be made in accordance with Fig. 19.10. The effective weld thickness shall be assumed as the thickness of the abutting plate t minus (c + f), where f is to be assigned a value of 0,2 t subject to a maximum of 3 mm. Where proof of fatigue strength is required (see Section 20), these welds are to be assigned to types D2 or D3. Fig. 19.9 Single and double-bevel welds with defined incomplete root penetration Fig. 19.10 Single and double-bevel welds with unwelded root face and defined incomplete root penetration 3.2.4Corner, T and double-T (cruciform) joints which are accessible from one side only may be made in accordance with Fig. 19.11 in a manner analogous to the butt joints referred to in 3.1.3 using a weld pool support (backing), or as single-side, single bevel welds in a manner similar to those prescribed in 3.2.2. The effective weld thickness shall be determined by analogy with 3.1.3 or 3.2.2, as appropriate. Wherever possible, these joints should not be used where proof of fatigue strength is required (see Section 20). 3.2.5Wherecornerjointsareflush;theweldshapesshallbeasshowninFig.19.12withbevellingofatleast30Eofthevertically drawn plates to avoid the danger of lamellar tearing. A similar procedure is tobefollowedin the case of fitted T joints (uniting three plates) where the abutting plate is to be socketed between the aligned plates. BKI - Rules for Hull - 2014
- 286. B Section 19 - Welded Joints19-8/20 Fig. 19.11 Single-side welded T joints Fig. 19.12 Flush fitted corner joints 3.2.6Where, in the case of T joints, the direction of the main stress lies in the plane of the horizontal plates (e.g. the plating) shown in Fig. 19.13 and where the connection of the perpendicular (web) plates is of secondary importance, welds uniting three plates may be made in accordance with Fig. 19.13 (with the exception of those subjected mainly to dynamic loads). For the root passes of the three plate weld sufficient penetration shall be achieved. Sufficient penetration has to be verified in way of the welding procedure test. Theeffectivethicknessoftheweldconnectingthehorizontalplatesshallbedeterminedinaccordancewith3.2.2.Therequisite "a"dimensionisdeterminedbythejointunitingthevertical(web)platesandshall,wherenecessary,bedeterminedanaccordance with Table 19.3 or by calculation as for fillet welds. Fig. 19.13 Welding together three plates 3.3 Fillet weld connections 3.3.1Inprinciple filletwelds are tobe ofthe double filletweldtype.Exceptionstothisrule(asinthecaseofclosed boxgirders and mainly shear stresses parallel to the weld) are subject to approval in each individual case. The throat thickness "a" of the weld (the height of the inscribed isosceles triangle) shall be determined in accordance with Table 19.3 or by calculation accordingtoC.Theleglengthofafilletweld is to be notlessthan1,4timesthethroatthickness"a".Forfilletweldsatdoubling plates, see 2.4.3; for the welding of the deck stringer to the sheer strake, see Section 7, A.2.1, and for bracket joints, see C.2.7. 3.3.2TherelativefilletweldthroatthicknessesspecifiedinTable19.3relatetonormalstrengthandhigherstrengthhullstructural steels and comparable structural steels. They may also be generally applied to high-strength structural steels and non-ferrous metals provided that the "tensile shear strength" of the weld metal used is at least equal to the tensile strength of the base material.Failingthis,the"a"dimensionshallbeincreasedaccordinglyandthenecessaryincrementshallbeestablishedduring the welding procedure test (see Rules for Welding, Volume VI, Section 12, F.). Alternatively proof by calculation taking account of the properties of the weld metal may be presented. Note : In case of higher strength aluminium alloys (e.g. AlMg4,5Mn0,7), such an increment may be necessary for cruciform joint subject to tensile stresses, as experience shows that in the welding procedure tests the tensile-shear strength of fillet welds (made with matching filler metal) often fails to attain the tensile strength of the base material. See also Rules for Welding Volume VI, Section 12, F. 3.3.3The throat thickness of fillet welds shall not exceed 0,7 times the lesser thickness of the parts to be connected (generally the web thickness). The minimum throat thickness is defined by the expression: BKI - Rules for Hull - 2014
- 287. Section 19 - Welded Joints B 19-9/20 amin = [mm] but not less than 3 mm t1 = lesser (e.g. the web) plate thickness [mm] t2 = greater (e.g. the flange) plate thickness [mm]. 3.3.4It is desirable that the fillet weld section shall be flat faced with smooth transitions to the base material. Where proof offatiguestrengthisrequired(seeSection20),machiningoftheweld(grindingtoremovenotches)mayberequireddepending on the notch category. The weld should penetrate at least close to the theoretical root point. 3.3.5Where mechanical welding processes are used which ensure deeper penetration extending well beyond the theoretical root point and where such penetration is uniformly and dependably maintained under production conditions, approval may be given for this deeper penetration to be allowed for in determining the throat thickness. The effective dimension: [mm] shall be ascertained in accordance with Fig. 19.14 and by applying the term "emin" to be established for each welding process by a welding procedure test. The throat thickness shall not be less than the minimumthroat thickness related to the theoretical root point. Fig. 19.14 Fillet welds with increased penetration 3.3.6When welding on top of shop primers which are particularly liable to cause porosity, an increase of the "a" dimension by up to 1 mm may be stipulated depending on the welding process used. This is specially applicable where minimum fillet weld throat thicknesses are employed. The size of the increaseshall be decided on a case by case basis considering the nature and severity of the stressing following the test results of the shop primer in accordance with the Rules for Welding, Volume VI, Section 12, F. This applies in analogous manner to welding processes where provision has to be made for inadequate root penetration. 3.3.7Strengthened fillet welds continuous on both sides are to be used in areas subjected to severe dynamic loads (e.g. for connecting the longitudinal and transverse girders of the engine base to top plates close to foundation bolts, see Section 8, C.3.2.5 and Table 19.3), unless single or double bevel welds are stipulated in these locations. In these areas the "a" dimension shall equal 0,7 times the lesser thickness of the parts to be welded. 3.3.8Intermittent fillet welds in accordance with Table 19.3 may be located opposite one another (chain intermittent welds, possibly with scallops) or may be staggered, see Fig. 19.15. In case of small sections other types of scallops may be accepted. In water and cargo tanks, inthebottomarea of fuel oil tanksand of spaces where condensed or sprayed water may accumulate and in hollow components (e.g. rudders) threatened by corrosion, only continuous or intermittent fillet welds with scallops shall be used. This applies accordingly also to areas, structures or spaces exposed to extreme environmental conditions or which are exposed to corrosive cargo. There shall be no scallops in areas where the plating is subjected to severe local stresses (e.g. in the bottom section of the fore ship) and continuous welds are to be preferred where the loading is mainly dynamic. BKI - Rules for Hull - 2014
- 288. B Section 19 - Welded Joints19-10/20 Fig. 19.15 Scallop, chain and staggered welds 3.3.9 The throat thickness au of intermittent fillet welds is to be determined according to the selected pitch ratio b/R by applying the formula: au = [mm] a = required fillet weld throat thickness [mm] for a continuous weld according to Table 19.3 or determined by calculation b = pitch = e + R [mm] e = interval between the welds [mm] R = length of fillet weld [mm] The pitch ratio b/R should not exceed 5. The maximum unwelded length (b - R with scallop and chain welds, or b/2 - R with staggered welds) should not exceed 25 times the lesser thickness of the parts to be welded. The length of scallops should, however, not exceed 150 mm. 3.3.10 Lap joints should be avoided wherever possible and are not to be used for heavily loaded components. In the case of components subject to low loads lap joints may be accepted provided that, wherever possible, they are orientated parallel to the direction of the main stress. The width of the lap shall be 1,5 t + 15 mm (t = thickness of the thinner plate). Except where another value is determined by calculation, the fillet weld throat thickness "a" shall equal 0,4 times the lesser plate thickness, subject to the requirement that it shall not be less than the minimum throat thickness required by 3.3.3. The fillet weld shall be continuous on both sides and shall meet at the ends. 3.3.11 Inthecaseofslotwelding,theslotsshould,whereverpossible,taketheformofelongatedholeslyinginthedirection of the main stress. The distance between the holes and the length of the holes may be determined by analogy with the pitch "b"andthefilletweldlength"R"intheintermittentweldscoveredby3.3.8.Thefilletweldthroatthickness"au"maybeestablished in accordance with 3.3.9. The width of the holes shall be equal to at least twice the thickness of the plate and shall not be less than 15 mm. The ends of the holes shall be semi-circular. Plates or sections placed underneath should at least equal theperforatedplateinthicknessandshouldprojectonbothsidestoadistance of1,5x the plate thickness subjecttoamaximum of 20 mm. Wherever possible only the necessary fillet welds shall be welded, while the remaining void is packed with a suitable filler. In special cases, instead of slot welding, plug weld may be approved by BKI. Lug joint welding is not allowed. 4. Welded joints of particular components 4.1 Welds at the ends of girders and stiffeners 4.1.1As shown in Fig. 19.16, the web at the end of intermittently welded girders or stiffeners is to be continuously welded to the plating or the flange plate, as applicable, over a distance at least equal to the depth "h" of the girder or stiffener subject to a maximum of 300 mm. Regarding the strengthening of the welds at the ends, extending normally over 0,15 of the span, see Table 19.3. BKI - Rules for Hull - 2014
- 289. Section 19 - Welded Joints B 19-11/20 Fig. 19.16 Welds at the ends of girders and stiffeners 4.1.2 Theareas of bracketplatesshouldbecontinuously welded over a distance atleastequaltothelengthofthe bracket plate. Scallops are to be located only beyond a line imagined as an extension of the free edge of the bracket plate. 4.1.3Whereverpossible,thefree ends of stiffeners shall abut against the transverse plating or the webs of sections andgirders so as to avoid stress concentrations in the plating. Failing this, the ends of the stiffeners are to be sniped and continuously welded over a distance of at least 1,7 h subject to a maximum of 300 mm. 4.1.4Where butt joints occur in flange plates, the flange shall be continuously welded to the web on both sides of the joint over a distance at least equal to the width of the flange. 4.2 Joints between section ends and plates 4.2.1Weldedjointsconnectingsectionendsandplatesmaybemadeinthesameplaneorlapped.Wherenodesigncalculations have been carried out or stipulated for the welded connections, the joints may be made analogously to those shown in Fig. 19.17. Fig. 19.17 Joints uniting section ends and plates 4.2.2 Where the joint lies in the plane of the plate, it may conveniently take the form of a single-bevel butt weld with fillet. Where the joint between the plate and the section end overlaps, the fillet weld shall be continuous on both sides and shallmeetattheends.Thenecessary"a"dimensionistobecalculatedinaccordancewithC.2.6.Thefilletweldthroatthickness is not to be less than the minimum specified in 3.3.3. 4.3 Welded shaft bracket joints 4.3.1Unless cast in one piece or provided with integrally cast welding flanges analogous to those prescribed in 2.1.7 (see Fig. 19.18), strut barrel and struts are to be connected to each other and to the shell plating in the manner shown in Fig. 19.19. 4.3.2 In the case of single-strut shaft brackets no welding is to be performed on the arm at or close to the position of constraint. Such components shall be provided with integrally forged or cast welding flanges. BKI - Rules for Hull - 2014
- 290. B Section 19 - Welded Joints19-12/20 Fig. 19.18 - Shaft bracket with integrally cast welding flanges t = plating thickness in accordance with Section 6, F. [mm] t' = [mm]where d < 50mm = [mm]where d 50mm For shaft brackets of elliptically shaped cross section d may be substituted by 2/3 d in the above formulae. Fig. 19.19 - Shaft bracket without integrally cast welding flanges 4.4 Rudder coupling flanges 4.4.1Unless forged or cast steel flanges with integrally forged or cast welding flanges in conformity with 2.1.7 are used, horizontal rudder coupling flanges are to be joined to the rudder body by plates of graduated thickness and full penetration single or double-bevel welds as prescribed in 3.2.1, see Fig. 19.20. See also Section 14, D.1.4 and D.2.4. 4.4.2Allowance shall be made for the reduced strength of the coupling flange in the thickness direction, see 1.5 and 2.5. In case of doubt, proof by calculation of the adequacy of the welded connection shall be produced. 4.4.3The welded joint between the rudder stock (with thickened collar, see 2.1.8) and the flange shall be made in accordance with Fig. 19.21a. For small stock diameter welded joint in accordance with Fig. 19.21b may be applied. BKI - Rules for Hull - 2014
- 291. Section 19 - Welded Joints B 19-13/20 t = plate thickness in accordance with Section 14, E.3.1 [mm] tf = actual flange thickness [mm] t' = [mm] where tf < 50 mm = [mm] where tf 50 mm Fig. 19.20 - Horizontal rudder coupling flanges Fig. 19.21a - Welded joint between rudder stock and coupling flange Fig. 19.21b - Welded joint between rudder stock and coupling flange for small stock diameter BKI - Rules for Hull - 2014
- 292. C Section 19 - Welded Joints19-14/20 C. Stress Analysis 1. General analysis of fillet weld stresses 1.1 Definition of stresses For calculation purposes, the following stresses in a fillet weld are defined (see also Fig. 19.22): Fz = normal stresses acting vertically to the direction of the weld seam Jz = shear stress acting vertically to the direction of the weld seam J## = shear stress acting in the direction of the weld seam. Fig. 19. 22 Stresses in a fillet weld Normal stresses acting in the direction of the weld seam need not be considered. For calculation purposes the weld seam area is a @ R Due to equilibrium condition the following applies to the flank area vertical to the shaded weld seam area Jz = Fz The equivalent stress is to be calculated by the following formula: Fv = 1.2 Definitions a = throat thickness [mm] R = length of fillet weld [mm] P = single force [N] M = bending moment at the position considered [Nm] Q = shear force at the point considered [N] S = first moment of the cross sectional area of the flange connected by the weld to the web in relationship to the neutral beam axis [cm3 ] I = moment of inertia of the girder section [cm4 ] W = section modulus of the connected section [cm3 ]. 2. Determination of stresses 2.1 Fillet welds stressed by normal and shear forces Flank and frontal welds are regarded as being equal for the purposes of stress analysis. In view of this, normal and shear stresses are calculated as follows: F = J = [N/mm2 ] BKI - Rules for Hull - 2014
- 293. Section 19 - Welded Joints C 19-15/20 Joint as shown in Fig. 19.23: Fig. 19.23 Weld joint of an overlapped lifting eye - Stresses in frontal fillet welds: Jz = [N/mm2 ] J## = [N/mm2 ] Ft = [mm2 ] - Stresses in flank fillet welds : Jz = [N/mm2 ] J## = [N/mm2 ] R1, R2, e [mm] - Equivalent stress for frontal and flank fillet welds: Fv = [N/mm2 ] Joint as shown in Fig. 19.24: Fig. 19.24 Weld joint of a vertically mounted lifting eye Jz = [N/mm2 ] J## = [N/mm2 ] – Equivalent stress : Fv = [N/mm2 ] BKI - Rules for Hull - 2014
- 294. C Section 19 - Welded Joints19-16/20 2.2 Fillet weld joints stressed by bending moments and shear forces The stresses at the fixing point of a girder are calculated as follows (in Fig. 19.25 a cantilever beam is given as an example): Fig. 19.25 Fixing point of cantilever beam .1 Normal stress due to bending moment: Fz(z) = [N/mm2 ] Fzmax = [N/mm2 ], if eu > e0 = [N/mm2 ], if eu < e0 .2 Shear stress due to shear force: J## (z) = [N/mm2 ] J## max = [N/mm2 ] Is = moment of inertia of the welded joint related to the x-axis [cm4 ] Ss (z)= the first moment of the connected weld section at the point under consideration [cm3 ] z = distance from the neutral axis [cm]. .3 Equivalent stress : IthastobeprovedthatneitherFzmax intheregionoftheflangenor max intheregionoftheneutralaxisnortheequivalent stress Fv= exceed the permitted limits given in 2.8 at any given point. The equivalent stress Fvshould always be calculated at the web-flange connection. 2.3 Fillet welded joints stressed by bending and torsional moments and shear forces Regardingthenormalandshearstressesresultingfrombending,see2.2.Torsionalstressesresultingfromthetorsionalmoment MT are to be calculated: JT = [N/mm2 ] MT = torsional moment [Nm] Am = sectional area [mm2 ] enclosed by the weld seam. The equivalent stress composed of all three components (bending, shear and torsion) is calculated by means of the following formulae: Fv = [N/mm2 ] where and JT have not the same direction Fv = [N/mm2 ] where and JT have the same direction. BKI - Rules for Hull - 2014
- 295. Section 19 - Welded Joints C 19-17/20 2.4 Continuous fillet welded joints between web and flange of bending girders The stresses are to be calculated in way of maximum shear forces. Stresses in the weld’s longitudinal direction need not to be considered. In the case of continuous double fillet weld connections the shear stress is to be calculated as follows: J## = [N/mm2 ] The fillet weld thickness required is: areq = [mm] 2.5 Intermittent fillet weld joints between web and flange of bending girders Shear stress : J## = [N/mm2 ] b = pitch " = 1,1 stress concentration factor which takes into account increases in shear stress at the ends of the fillet weld seam "R ". Fig. 19.26 Intermittent fillet weld joint The fillet weld thickness required is : areq = [mm] 2.6 Fillet weld connections on overlapped profile joints 2.6.1Profiles joined by means of two flank fillet welds (see Fig. 19.27): Jz = [N/mm2 ] J## = [N/mm2 ] Fig. 19.27 Profile joined by means of two flank fillet joints The equivalent stress is : Fv = [N/mm2 ] BKI - Rules for Hull - 2014
- 296. C Section 19 - Welded Joints19-18/20 c, d, R1, R2, r [mm] see Fig. 19.27 c = [mm] As the influence of the shear force can generally be neglected, the required fillet weld thickness may be determined by the following formula : areq = [mm] 2.6.2 Profiles joined by means of two flank and two frontal fillet welds (all round welding as shown in Fig. 19.28): Jz = [N/mm2 ] J## = [N/mm2 ] The equivalent stress is : Fv = [N/mm2 ] areq = [mm] Fig. 19.28 Profile joined by means of two flank and two frontal fillet welds (all round welding) 2.7 Bracket joints Where profiles are joined to brackets as shown in Fig. 19.29, the average shear stress is : J = [N/mm2 ] d = length of overlap [mm] Fig. 19.29 Bracket joint with idealized stress distribution resulting from moment M and shear force Q The required fillet weld thickness is to be calculated from the section modulus of the profile as follows : areq = [mm]. (The shear force Q has been neglected.) 2.8 Permissible stresses The permissible stresses for various materials under mainly static loading conditions are given in Table 19.2. The values listed for high strength steels, austenitic stainless steels and aluminium alloys are based on the assumption that the strength BKI - Rules for Hull - 2014
- 297. Section 19 - Welded Joints C 19-19/20 values of the weld metal used are at least as high as those of the parent metal. If this is not the case, the "a" value calculated shall be increased accordingly (see also B.3.3.2). Table 19.2 - Permissible stresses in fillet weld seams Material ReH or Rp0,2 [N/mm2 ] Permissible stresses [N/mm2 ] equivalent stress, shear stress Fvp, Jp normal strength hull structural steel KI - A/B/D/E 235 115 higher strength hull structural steel KI - A/D/E/F 32 315 145 KI - A/D/E/F 36 355 160 KI - A/D/E/F 40 390 175 high strength steels S 460 460 200 S 690 685 290 austenitic and austenitic- ferritic stainless steels 1.4306/304 L 180 110 1.4404/316 L 190 1.4435/316 L 190 1.4438/317 L 195 1.4541/321 205 1.4571/316 Ti 215 1.4406/316 LN 280 1301.4429/316 LN 295 1.4439/317 LN 285 1.4462/318 LN 480 205 aluminium alloys Al Mg 3/5754 80 1) 35 AlMg4,5Mn0,7/5083 125 1) 56 Al Mg Si/6060 652) 30 Al Mg Si Mn/6082 110 2) 45 1) Plates, soft condition 2) Sections, cold hardened BKI - Rules for Hull - 2014
- 298. C Section 19 - Welded Joints19-20/20 Table 19.3 - Fillet Weld Connections Structural parts to be connected Basic thickness of fillet welds a / t0 1) for double continuous fillet welds 2) Intermittent fillet welds permissible 3) Bottom structures transverse and longitudinal girders to each other – to shell and inner bottom centre girder to flat keel and inner bottom transverse and longitudinal girders and stiffeners including shell plating in way of bottom strengthening forward machinery space transverse and longitudinal girders to each other – to shell and inner bottom inner bottom to shell sea chests, water side inside 0,35 0,20 0,40 0,30 0,35 0,30 0,40 0,50 0,30 × × Machinery foundation longitudinal and transverse girders to each other and to the shell – to inner bottom and face plates – to top plates – in way of foundation bolts – to brackets and stiffeners longitudinal girders of thrust bearing to inner bottom 0,40 0,40 0,50 4) 0,70 4) 0,30 0,40 Decks to shell (general) deckstringer to sheerstrakes (see also Section 7, A.2) 0,40 0,50 Frames, stiffeners, beams etc. general in peak tanks bilge keel to shell 0,15 0,30 0,15 × × Transverse, longitudinal and transverse girders general within 0,15 of span from supports. cantilevers pillars to decks. 0,15 0,25 0,40 0,40 × Bulkheads, tank boundaries, walls of superstructures and deckhouses. to decks, shell and walls. 0,40 Hatch coamings to deck (see also Section 17, C.1.8) to longitudinal stiffeners 0,40 0,30 Hatch covers general watertight or oiltight fillet welds. 0,15 0,30 × 5) Rudder plating to webs 0,25 × Stem plating to webs 0,25 × 1) t0 = thickness of the thinner plate. 2) In way of large shear forces larger throat thicknesses may be required on the bases of calculations according to C. 3) For intermittent welding in spaces liable to corrosion B.3.3.8 is to be observed. 4) Forplatethicknessesexceeding15mmsingleordoublebevelbuttjointswith,fullpenetrationorwithdefinedincompleterootpenetration according to Fig. 19.9 to be applied. 5) Excepting hatch covers above holds provided for ballast water. BKI - Rules for Hull - 2014
- 299. Section 20 - Fatigue Strength A 20-1/20 Section 20 Fatigue Strength Preamble The proof of sufficient fatigue strength, i.e. the strength against crack initiation under dynamic loads during operation, is useful for judging and reducing the probability of crack initiation of structural members during the design stage. Due to the randomness of the load process, the spreading of material properties and fabrication factors and to effects of ageing, crack initiation cannot be completely excluded during later operation. Therefore among other things periodical surveys are necessary. A. General 1. Definitions Fig. 20.1 Dynamic Load cycle )F = applied stress range (Fmax S Fmin) [N/mm2 ], see also Fig. 20.1 Fmax = maximum upper stress of a stress cycle [N/mm2 ] Fmin = maximum lower stress of a stress cycle [N/mm2 ] Fm = mean stress (Fmax/2 + Fmin/2) [N/mm2 ] )Fmax = applied peak stress range within a stress range spectrum [N/mm2 ] )Fp = permissible stress range [N/mm2 ] )J = corresponding range for shear stress [N/mm2 ] n = number of applied stress cycles N = number of endured stress cycles according to S-N curve (= endured stress cycles under constant amplitude loading) )FR = fatigue strength reference value of S-N curve at 2 @ 106 cycles of stress range [N/mm2 ] (= detail category number according to Table 20.3) fm = correction factor for material effect fR = correction factor for mean stress effect fw = correction factor for weld shape effect fi = correction factor for importance of structural element fs = additional correction factor for structural stress analysis fn = factor considering stress spectrum and number of cycles for calculation of permissible stress range. )FRc = corrected fatigue strength reference value of S-N curve at 2 @ 106 stress cycles [N/mm2 ] D = cumulative damage ratio. BKI - Rules for Hull - 2014
- 300. A Section 20 - Fatigue Strength20-2/20 2. Scope 2.1 A fatigue strength analysis is to be performed for structures which are predominantly subjected to cyclic loads. Items of equipment, e.g. hatch cover resting pads or equipment holders, are thereby also to be considered. The notched details i. e. the welded joints as well as notches at free plate edges are to be considered individually. The fatigue strength assessment is to be carried out either on the basis of a permissible peak stress range for standard stress spectra (see B.2.1) or on the basis of a cumulative damage ratio (see B.2.2). 2.2 No fatigue strength analysis is required if the peak stress range due to dynamic loads in the seaway (stress spectrum A according to 2.4) and/or due to changing draught or loading conditions, respectively, fulfils the following conditions: – peak stress range only due to seaway-induced dynamic loads: )Fmax 2,5 )FR – sumof the peak stress ranges due to seawayinduced dynamic loads and due to changes of draught or loading condition, respectively: )Fmax 4,0 )FR Note For welded structures of detail category 80 or higher a fatigue strength analysis is required only in case of extraordinary high dynamic stresses. 2.3 The rules are applicable to constructions made of normal and higher-strength hull structural steels according to Section 2, B. as well as aluminium alloys. Other materials such as cast steel can be treated in an analogous manner by using appropriate design S-N curves. Low cycle fatigue problems in connection with extensive cyclic yielding have to be specially considered. When applying the following rules, the calculated nominal stress range should not exceed 1,5 times the minimum nominal upper yield point. In special cases the fatigue strength analysis may be performed by considering the local elasto-plastic stresses. 2.4 The stress ranges )F which are to be expected during the service life of the ship or structural component, respectively, may be described by a stress range spectrum (long-term distribution of stress range). Fig. 20.2 shows three standard stress range spectra A, B and C, which differ from each other in regard to the distribution of stress range )F as a function of the number of load cycles. A : straight-line spectrum (typical stress range spectrum of seaway-induced stress ranges) B : parabolic spectrum (approximated normal distribution of stress range )F acc. to DIN 15018) C : rectangular spectrum (constant stress range within the whole spectrum; typical spectrum of engine- or propeller-excited stress ranges). Fig. 20.2 Standard stress range spectra A, B and C In case of only seaway-induced stresses, for a design lifetime of about 20 years normally the stress range spectrum A is to be assumed with a number of cycles nmax = 5 @ 107 . For design lifetime of 30 years the number of cycles nmax = 7,5 @ 107 is to be assumed. The maximum and minimum stresses result from the maximum and minimum relevant seaway-induced load effects. The BKI - Rules for Hull - 2014
- 301. Section 20 - Fatigue Strength A 20-3/20 different load -effects for the calculation of )Fmax are, in general, to be superimposed conservatively. Table 20.1 shows examples for the individual loads which have to be considered in normal cases. Under extreme seaway conditions stress ranges exceeding )Fmax occur (see Section 5, C.8.). These stress ranges, which load cycles are to be generally assumed with n < 104 , can be neglected regarding the fatigue life, when the stress ranges )Fmax derived from loads according to Table 20.1 are assigned to the spectrum A. For ships of unconventional hull shape and for ships for which a special mission profile applies, a stress range spectrum deviating from spectrum A may be applied which may be evaluated by the spectral method. Other significant fluctuating stresses, e.g. in longitudinals due to deflections of supporting transverses (see Section 9, B.3.5), in longitudinal and transverse structures due to torsional deformations (see for this also Section 5, F.1.1) as well as additional stresses due to the application of non-symmetrical sections, have to be considered, see Section 3, L. 2.5 Additional stress cycles resulting from changing mean stresses, e.g. due to changing loading conditions or draught, need generally not be considered as long as the seaway-induced stress ranges are determined for the loading condition being most critical with respect to fatigue strength and the maximum change in mean stress is less than the maximum seaway-induced stress range. Larger changes in mean stress are to be included in the stress range spectrum by conservative superpositioning of the largest stress ranges ( e.g. in accordance with the "rainflow counting method" ). If nothing else is specified, 103 load cycles have to be assumed for changes in loading condition or draught. 2.6 The fatigue strength analysis is, depending on the detail considered, based on one of the following types of stress: – For notches of free plate edges the notch stress Fk, determined for linear - elastic material behaviour, is relevant, which can normally be calculated from a nominal stress Fn and a theoretical stress concentration factor Kt. Values for Kt are given in Section 3, J., Figs. 3.8 and 3.9 for different types of cut-outs. The fatigue strength is determined by the detail category (or )FR) according to Table.20.3, type E2 and E3. – For welded joints the fatigue strength analysis is normally based on the nominal stress Fn at the structural detail considered and on an appropriate detail classification as given in Table 20.3, which defines the detail category (or )FR). – For those welded joints, for which the detail classification is not possible or additional stresses occur, which are not or not adequately considered by the detail classification, the fatigue strength analysis may be performed on the basis of the structural stress Fs in accordance with C. BKI - Rules for Hull - 2014
- 302. A Section 20 - Fatigue Strength20-4/20 Table 20.1 Maximum and minimum value for seaway-induced cyclic loads Load Maximum load Minimum load Vertical longitudinal bending moments (Section 5, B.)1) MSW + MST + fQ.MWVhog MSW + MST + fQ.MWVsag Vertical bending moments and horizontal wave bending moments 1) (Section 5, B.) MSW + MST + fQ.(0,6.MWVhog + MWH) MSW + MST + fQ.(0,6.MWVhog - MWH) Vertical longitudinal bending moments , horizontal wave bending moments and torsional moments1) (Section 5, B.) fF.{MSW + MST + fQ.[(0,43+C).MWVhog + MWH + MWT]} fF.{MSW + MST + fQ.[(0,43+C.(0,5-C)).MWVhog + C.(0,43+C).MWVsag - MWH - MWT]} C = Loads on weather decks 2) Section 4, B.1.) pD 0 Loads on ship’s sides 2), 4) – below T – above T (Section 4, B.2.) 10 (T S z) + p0 @ cF p0 @ cF 10 (T S z) S p0 @ cF but $ 0 0 Loads on ship’s bottom 2), 4) (Section 4, B.3.) 10 T + p0 @ cF 10 T S p0 @ cF Liquid pressure in completely filled tanks 4) (Section 4, D.1.) 9,81@ h1 @ D (1 + av) + 100 pv or 9,81 @ D ”h1@ cos n + (0,3@ b + y)sin n ] + 100 pv 9,81@ h1 @ D (1 S av) + 100 pv or 9,81 @ D ”h1@ cos n + (0,3@ b S y)sin n ] + 100 pv but 100 pv Loads due to cargo 5) (Section 4, C.1.1 and E.1) p (1 + av) p @ ax @ 0,7 p @ ay @ 0,7 p (1 S av ) S p @ ax @ 0,7 S p @ ay @ 0,7 Loads due to friction forces 3) (Section 17, B.4.5.5) Ph S Ph Loads due to rudder forces 3) (Section 14, B.) CR QR – CR – QR 1) Maximum and minimum load are to be so determined that the largest applied stress range )F as per Figure 20.1 at conservative mean stress is obtained having due regard to the sign (plus, minus). For fF, fQ see Section 5.D.1 2) With probability factor f for calculation p0 according to Section 4, A.2.2.: however f = 1,0 for stiffeners if no other cyclic load components are considered 3) In general the largest friction load is to be taken in connection with the load spectrum B without considering further cyclic loads. 4) Assumption of conservative super positioning for the shell: Where appropriate, proof is to be furnished for Tmin. 5) Probability factor fQ = 1,0 used for determination of a0 and further calculation of ax and ay according to Section 4, E.1. 3. Quality requirements (fabrication tolerances) 3.1 The detail classification of the different welded joints as given in Table 20.3 is based on the assumption that the fabrication of the structural detail or welded joint, respectively, corresponds in regard to external defects at least to quality group B according to DIN EN ISO 5817 and in regard t internal defects at least to quality group C. Further information about the tolerances can also be found in the Rules for Welding, Volume VI, Appendix 6. 3.2 Relevant information have to be included in the manufacturing document for fabrication. If it is not possible to comply with the tolerances given in the standards this has to be accounted for when designing the structural details or welded joints, respectively. In special cases an improved manufacture as stated in 3.1 may be required, e.g. stricter tolerances or improved weld shapes, .see also B.3.2.4. 3.3 The following stress increase factors km for considering significant influence of axial and angular misalignment are already included in the fatigue strength reference values )FR (Table 20.3) : BKI - Rules for Hull - 2014
- 303. Section 20 - Fatigue Strength A, B 20-5/20 km = 1,15 butt welds (corresponding type A1, A2, A11) = 1,30 butt welds (corresponding type A3–A10) = 1,45 cruciform joints (corresponding type D1–D5) = 1,25 fillet welds on one plate surface (corresponding type C7,C8) Other additional stresses need to be considered separately. B. Fatigue Strength Analysis for Free Plate Edges and for Welded Joints Using Detail Classification 1. Definition of nominal stress and detail Classification for welded joints 1.1 Corresponding to their notch effect, welded joints are normally classified into detail categories considering particulars in geometry and fabrication, including subsequent quality control, and definition of nominal stress. Table 20.3 shows the detail classification based on recommendations of the International Institute of Welding (IIW) giving the detail category number (or )FR) for structures made of steel or aluminium alloys (Al). In Table 20.4 )FR-values for steel are given for some intersections of longitudinal frames of different shape and webs, which can be used for the assessment of the longitudinal stresses. It has to be noted that some influence parameters cannot be considered by the detail classification and that a large scatter of fatigue strength has therefore to be expected. 1.2 Details which are not contained in Table 20.3 may be classified either on the basis of local stresses in accordance with C. or, else, by reference to published experimental work or by carrying out special fatigue tests, assuming a sufficiently high confidence level (see 3.1) and taking into account the correction factors as given in C.4. 1.3 Regarding the definition of nominal stress, the arrows in Table 20.3 indicate the location and direction of the stress for which the stress range is to be calculated. The potential crack location is also shown in Table 20.3. Depending on this crack location, the nominal stress range has to be determined by using either the cross sectional area of the parent metal or the weld throat thickness, respectively. Bending stresses in plate and shell structures have to be incorporated into the nominal stress, taking the nominal bending stress acting at the location of crack initiation. Note: The factor Ks for the stress increase at transverse butt welds between plates of different thickness (see type A5 in Table 20.3) can be estimated in a first approximation as follows : Ks = t1 = smaller plate thickness t2 = larger plate thickness Additional stress concentrations which are not characteristic of the detail category itself, e.g. due to cut-outs the neighbourhood of the detail, have also to be incorporated into the nominal stress. 1.4 In the case of combined normal and shear stress the relevant stress range may be taken as the range of the principal stress at the potential crack location which act approximately perpendicular (within ± 45o ) to the crack front as shown in Table 20.3 as long as it is larger than the individual stress components . 1.5 Where solely shear stresses are acting the largest principal stress F1 = J may be used in combination with the relevant detail category. 2. Permissible stress range for standard stress range spectra or calculation of the cumulative damage ratio 2.1 For standard stress range spectra according to Fig. 20.2, the permissible peak stress range can be calculated as follows: )Fp = fn @ )FRc )FRc = detail category or fatigue strength reference value, respectively, corrected according to 3.2 fn = factor as given in Table 20.2. BKI - Rules for Hull - 2014
- 304. B Section 20 - Fatigue Strength20-6/20 The peak stress range of the spectrum shall not exceed the permissible value, i.e. )Fmax )Fp 2.2 If the fatigue strength analysis is based on the calculation of the cumulative damage ratio, the stress range spectrum expected during the envisaged service life is to be established (see A.2.4) and the cumulative damage ratio D is to be calculated as follows : D = I = total number of blocks of the stress range spectrum for summation (normally I $ 20) ni = number of stress cycles in block i Ni = number of endured stress cycles determined from the corrected design S-N curve (see 3.) taking )F = )Fi )Fi = stress range of block i. To achieve an acceptable high fatigue life, the cumulative damage sum should not exceed D = 1. If the expected stress range spectrum can be superimposed by two or more standard stress spectra according to A.2.4, the partial damage ratios Di due to the individual stress range spectra can be derived from Table 20.2. In this case a linear relationship between number of load cycles and cumulative damage ratio may be assumed. The numbers of load cycles given in Table 20.2 apply for a cumulative damage ratio of D = 1. 3. Design S-N Curves 3.1 Description of the design S-N curves 3.1.1The design S-N curves for the calculation of the cumulative damage ratio according to 2.2 are shown in Fig. 20.3 for welded joints at steel and in Fig. 20.4 for notches at plate edges of steel plates. For aluminium alloys (Al) corresponding S-N curves apply with reduced detail categories )FR acc. to Table 20.3. The S-N curves represent the lower limit of the scatter band of 95 % of all test results available (corresponding to 97,5 % survival probability) considering further detrimental effects in large structures. To account for different influence factors, the design S-N curves have to be corrected according to 3.2. 3.1.2The S-N curves represent section wise linear relationships between log ()F) and log (N): log (N) = 7,0 + m @ Q Q = log ()FR/)F) S 0,69897/m0 m = slope exponent of S-N curve, see 3.1.3 and 3.1.4 m0 = inverse slope in the range N 1 @ 107 = 3 for welded joints = 3,5 ÷ 5 for free plate edges. (see Fig. 20.4) The S-N curve for detail category 160 forms the upper limit also for the S-N curves of free edges of steel plates with detail categories 100 – 140 in the range of low stress cycles, see Fig. 20.4. The same applies accordingly to detail categories 71 or 80 of aluminium alloys, see type E1 in Table 20.3. 3.1.3For structures subjected to variable stress ranges, the S-N curves shown by the solid lines in Fig. 20.3 and Fig. 20.4 have to be applied (S-N curves of type "M"), i.e. m = m0 for N 107 (Q < 0) = 2 @ m0 S 1 for N > 107 (Q > 0) BKI - Rules for Hull - 2014
- 305. Section 20 - Fatigue Strength B 20-7/20 Table 20.2 - Factor fn for the determination of the permissible range for standard stress range spectra Stress range Welded Joints Plates Edges (m0 = 3) n max = type E1 (m0 = 5) n max = type E2 (m0 = 4) n max = type E3 (m0 = 3,5) n max = 103 105 5 × 107 108 103 105 5 × 107 108 103 105 5 × 107 108 103 10 5 5 × 107 108 A (17,2) 3,53 3,02 (8,1) 3,63 3,32 (9,2) 3,68 3,36 10,3 12,22) 3,65 3,19 B (9,2) 1,67 1,43 (9,5) 5,0 1,95 1,78 (11,2) 5,9 1,86 1,65 6,6 7,52) 1,78 1,55 C (12,6) 2,71 0,424 0,5431) 0,369 0,5261) 4,57 1,82 0,606 0,6731) 0,561 0,6531) (5,2) 2,11 0,532 0,6211) 0,482 0,6021) (8,8) 2,35 0,483 0,5871) 0,430 0,5691) For definition of type E1 to type E3 see Table 20.3 For definition of m0 see 3.1.2 The values given in parentheses may be applied for interpolation. For interpolation between any pair of values (nmax1 ; fn1 ) and (nmax2 ; fn2 ), the following formula may be applied in the case of stress spectrum A or B: For the stress spectrum C intermediate values may be calculated according to 3.1.2 by taking N = n max and f n = )F/)FR. 1) fn for non-corrosive environment, see also 3.1.4. 2) for )FR = 100 [N/mm2 ] 3.1.4For stress ranges of constant magnitude (stress range spectrum C) in non-corrosive environment from N = 1 @ 107 the S-N curves of type "O" in Fig. 20.3 and 20.4 can be used, thus: m = m0 for N 107 (Q < 0) = 22 for N > 107 (Q > 0) 3.2 Correction of the reference value of the design S-N curve 3.2.1A correction of the reference value of the S-N curve (or detail category) is required to account for additional influence factors on fatigue strength as follows: )FRc = fm @ fR @ fw @ fi @ ft @)FR fm, fR, fw, fi, ft defined in 3.2.2 - 3.2.6 For the description of the corrected design S-N curve, the formulae given in 3.1.2 may be used by replacing )FR by )FRc. 3.2.2Material effect (fm) For welded joints it is generally assumed that the fatigue strength is independent of steel strength, i.e. : fm = 1,0. For free edges at steel plates the effect of the material's yield point is accounted for as follows : fm = 1 + ReH = minimum nominal upper yield point of the steel [N/mm2 ]. For aluminium alloys, f m = 1 generally applies. BKI - Rules for Hull - 2014
- 306. B Section 20 - Fatigue Strength20-8/20 Fig. 20.3 S-N Curves for welded joint steel Fig. 20.4 S-N Curves for notch at plate edge steel plate 3.2.3Effect of mean stress (fR) The correction factor is calculated as follows : – in the range of tensile pulsating stresses, i.e. Fm fR = 1,0 – in the range or alternating stresses, i.e. fR = 1 + c – in the range of compressive pulsating stresses, i.e. BKI - Rules for Hull - 2014
- 307. Section 20 - Fatigue Strength B 20-9/20 Fm fR = 1 + 2 @ c c = 0 for welded joints subjected to constant stress cycles (stress range spectrum C) = 0,15 for welded joints subjected to variable stress cycles (corresponding to stress range spectrum A or B) = 0,3 for unwelded base material. 3.2.4Effect of weld shape (fw) In normal cases: fw = 1,0. A factor f w > 1,0 applies for welds treated e.g. by grinding. By this surface defects such as slag inclusions, porosity and crack-like undercuts shall be removed and a smooth transition from the weld to the base material shall be achieved. Final grinding shall be performed transversely to the weld direction. The depth should be approx. 0,5 mm larger than that of visible undercuts. For ground weld toes of fillet and K- butt welds machined by: ! disk grinder fw = 1,15. ! burr grinder fw = 1,30 For butt welds ground flush the corresponding detail category has to be chosen, e.g. type A1, A10 or A12 in Table 20.3. For endings of stiffeners or brackets, e.g. type C4 or C6 in Table 20.3, which have a full penetration weld and are completely ground flush to achieve a notch-free transition, the following factor applies: fw = 1,4 The assessment of a local post-weld treatment of the weld surface and the weld toe by other methods e.g. ultrasonic impact treatment has to be agreed on in each case. 3.2.5Influence of importance of structural element (fi) In general the following applies: fi = 1,0. For secondary structural elements failure of which may cause failure of larger structural areas, the correction factor fi is to be taken as: fi = 0,9. For notches at plate edges in general the following correction factor is to be taken which takes into account the radius of rounding: fi = 0,9 + 5/r 1,0. r = notch radius [mm]; for elliptical roundings the mean value of the two main half axes may be taken. 3.2.6 Plate thickness effect (ft) In order to account for the plate thickness effect, application of the reduction factor ft is required by BKI for butt welds oriented transversely to the direction of applied stress for plate thicknesses t > 25 mm. ft = n = 0,17 as welded n = 0,10 toe-ground For all other weld connections consideration of the thickness effect may be required subject to agreement with BKI. BKI - Rules for Hull - 2014
- 308. C Section 20 - Fatigue Strength20-10/20 C. Fatigue Strength Analysis for Welded Joints Based on Local Stresses 1. Alternatively to the procedure described in the preceding paragraphs, the fatigue strength analysis for welded joints may be performed on the basis of local stresses. For common plate and shell structures in ships the assessment based on the so called structural (or hot-spot) stress Fs is normally sufficient. The structural stress is defined as the stress being extrapolated to the weld toe excluding the local stress concentration in the local vicinity of the weld, see Fig. 20.5. Fig. 20.5 Structural stress 2. The structural stress can be determined by measurements or numerically e.g. by the finite element method using shell or volumetric models under the assumption of linear stress distribution over the plate thickness. Normally the stress is extrapolated linearly to the weld toe over two reference points which are located 0,5 and 1,5 × plate thickness away from the weld toe. In some cases the structural stress can be calculated from the nominal stress Fn and a structural stress concentration factor Ks, which has been derived from parametric investigations using the methods mentioned. Parametric equations should be used with due consideration of their inherent limitations and accuracy. 3. For the fatigue strength analysis based on structural stress, the S-N curves shown in Fig. 20.3 apply with the following reference values: )FR = 100 (resp. 40 for Al) for the butt welds type A1 - A6 and K-butt welds with fillet welded ends, e.g. type D1 in Table 20.3, and for fillet welds which carry no load or only part of the load of the attached plate, type C1-C9 in Table 20.3 )FR = 90 (resp. 36 for Al) for fillet welds, which carry the total load of the attached plate, e.g. types D2 in Table 20.3. In special cases, where e.g. the structural stresses are obtained by non-linear extrapolation to the weld toe and where they contain a high bending portion, increased reference values of up to 15% can be allowed. 4. The reference value )FRc of the corrected S-N curve is to be determined according to B.3.2, taking into account the following additional correction factor which describes influencing parameters not included in the calculation model such as e.g. misalignment : fs = )Fs,max = applied peak stress range within a stress range spectrum )Fs,b = bending portion of )Fs,max k´m = km ! 0,05 km = stress increase factor due to misalignment under axial loading, at least km according A.3.3 The permissible stress range or cumulative damage ratio, respectively, has to be determined according to B.2. 5. In addition to the assessment of the structural stress at the weld toe, the fatigue strength with regard to root failure has to be considered by analogous application of the respective detail category, e.g. type D3 of Table 20.3. In this case the relevant stress is the stress in the weld throat caused by the axial stress in the plate perpendicular to the weld. It is to be converted at a ratio of t/2a. BKI - Rules for Hull - 2014
- 309. Section 20 - Fatigue Strength C 20-11/20 Table 20.3 Catalogue of Details A. Butt welds, transverse loaded Type No. Joint configuration showing mode of fatigue cracking and stress F considered Description of joint Detail category )FR Steel Al A1 Transverse butt weld ground flush to plate, 100% NDT (Non Destructive Testing) 112 45 A2 Transverse butt weld made in the shop in the flat position, max. weld reinforcement 1 mm + 0,1 x weld width, smooth transitions, NDT 90 36 A3 Transverse butt welds not satisfying conditions for joint type No.A2, NDT 80 32 A4 Transverse butt weld on backing strip or three-plate connection with unloaded branch Butt weld, welded on ceramic backing, root crack 71 80 25 28 A5 Transverse butt welds between plates of different widths or thickness, NDT as for joint type No. 2, slope 1 : 5 as for joint type No. 2, slope 1 : 3 as for joint type No. 2, slope 1 : 2 90 80 71 32 28 25 as for joint type No.3, slope 1 : 5 as for joint type No.3, slope 1 : 3 as for joint type No.3, slope 1 : 2 80 71 63 25 22 20 For the third sketched case the slope results from the ratio of the difference in plate thicknesses to the breadth of the welded seam. Additional bending stress due to thickness change to be considered, see also B.1.3. A6 Transverse butt welds welded from one side without backing bar, full penetration root controlled by NDT 71 28 not NDT 36 12 For tubular profiles )FR may be lifted to the next higher detail category A7 Partial penetration butt weld; the stress is to be related to the weld throat sectional area, weld overfill not to be taken into account 36 12 BKI - Rules for Hull - 2014
- 310. C Section 20 - Fatigue Strength20-12/20 Table 20.3 Catalogue of Details (Continued) A. Butt welds, transverse loaded Type No. Joint configuration showing mode of fatigue cracking and stress F considered Description of joint Detail category )FR Steel Al A8 Full penetration butt weld at crossing flanges Welded from both sides. 50 18 A9 Full penetration butt weld at crossing flanges 63 22 Welded from both sides Cutting edges in the quality according to type E2 or E3 Connection length w $ 2b Fnominal= A10 Full penetration butt weld at crossing flanges 80 32 Welded from both sides, NDT, weld ends ground, butt weld ground flush to surface Cutting edges in the quality according to type E2 or E3 with )FR = 125 Connection length w $ 2b Fnominal= A11 Full penetration butt weld at crossing flanges 90 36 Welded from both sides made in shop at flat position, radius transition with R $ b Weld reinforcement # 1 mm + 0,1 x weld width, smooth transitions, NDT, weld ends ground Cutting edges in the quality according to type E2 or E3 with )FR = 125 A12 Full penetration butt weld at crossing flanges, radius transition with R $ b 100 40 Welded from both sides, no misalignment, 100 % NDT, weld ends ground, butt weld ground flush to surface Cutting edges broken or rounded according to type E2 BKI - Rules for Hull - 2014
- 311. Section 20 - Fatigue Strength C 20-13/20 Table 20.3 Catalogue of Details (Continued) B. Longitudinal load-carrying weld Type No. Joint configuration showing mode of fatigue cracking and stress F considered Description of joint Detail category )FR Steel Al B1 Longitudinal butt welds both sides ground flush parallel to load direction without start/stop positions, NDT with start/stop positions 125 125 90 50 50 36 B2 Continuous automatic longitudinal fully penetrated K-butt weld without stop/start positions (based on stress range in flange adjacent to weld) 125 50 B3 Continuous automatic longitudinal fillet weld penetrated K-butt weld without stop / start positions (based on stress range in flange adjacent to weld) 100 40 B4 Continuous manual longitudinal fillet or butt weld (based on stress range in flange adjacent to weld) 90 36 B5 Intermittent longitudinal fillet weld (based on stress range in flange at weld ends) 80 32In presence of shear J in the web, the detail category has to be reduced by the factor (1 - )J / )F), but not below 36 (steel) or 14 (Al). B6 Longitudinal butt weld, fillet weld or intermittent fillet weld with cut outs (based on stress range in fillet at weld ends) 71 28 If cut outs is higher than 40% of web height 63 25 In presence of shear J in the web, the detail category has to be reduced by the factor (1 - )J / )F), but not below 36 (steel) or 14 (Al). Note For S-shaped scallops, an assessment based on local stresses is recommended. BKI - Rules for Hull - 2014
- 312. C Section 20 - Fatigue Strength20-14/20 Table 20.3 Catalogue of Details (Continued) C. Non-load-carrying attachments Type No. Joint configuration showing mode of fatigue cracking and stress F considered Description of joint Detail category )FR Steel Al C1 Longitudinal gusset welded on beam flange, bulb or plate : R # 50 mm 50 mm < R # 150 mm 150 mm < R # 300 mm R > 300 mm 80 71 63 56 28 25 20 18 For t2 # 0,5 t1, )FR may be increased by one category, but not over 80 (steel) or 28 (Al); not valid for bulb profiles. When welding close to edges of plates or profiles (distance less than 10 mm) and/or the structural element is subjected to bending, )FR is to be decreased by one category. C2 Gusset with smooth transition (sniped end or radius) welded on beam flange, bulb or plate; c # 2t2 , max 25 mm r $ 0,5 h r < 0,5 h or n # 20E n > 20E see joint type C1 For t2 # 0,5 t1, )FR may be increased by one category; not valid for bulb profiles. When welding close to edges of plates or profiles (distance less than 10 mm), )FR is to be decreased by one category. 71 63 25 20 C3 Fillet welded non-load-carrying lap joint welded to longitudinally stressed component. – flat bar – to bulb section – to angle section For R > 150 mm, )FR has to be decreased by one category, while for R # 50 mm, )FR may be increased by one category. If the component is subjected to bending, )FR has to be reduced by one category. 56 56 50 20 20 18 C4 Fillet welded lap joint with smooth transition (sniped end with n # 20E or radius) welded to longitudinally stressed component. – flat bar – to bulb section – to angle section c # 2 t, max. 25 mm 56 56 50 20 20 18 BKI - Rules for Hull - 2014
- 313. Section 20 - Fatigue Strength C 20-15/20 Table 20.3 Catalogue of Details (Continued) C. Non-load-carrying attachments Type No Joint configuration showing mode of fatigue cracking and stress F considered Description of joint Detail category )FR Steel Al C5 Longitudinal flat side gusset welded on plate or beam flange edge R # 50 mm 50 mm < R # 150 mm 150 mm < R # 300 mm R > 300 mm 56 50 45 40 20 18 16 14 For t2 # 0,7 t1, )FR may be incresed by one category, but not over 56 (steel) or 20 (Al). If the plate or beam flange is subjected to in-plane bending, )FR has to be decreased by one category. C6 Longitudinal flat side gusset welded on plate edge or beam, flange edge, with smooth transition (sniped end or radius); c # 2 t2, max. 25 mm r $ 0,5 h r < 0,5 h or n # 20E n > 20E see joint type C5 For t2 # 0,7 t1, )FR may be increased by one category. 50 45 18 16 C7 Transverse stiffener with fillet welds (applicable for short and long stiffeners). 80 28 C8 Non-load-carrying shear connector 80 28 C9 End of long doubling plate on beam, welded ends (based on stress range in flange at weld toe) tD # 0,8 t 0,8 t < tD # 1,5 t tD > 1,5 t The following features increase )FR by one category accordingly: – reinforced ends according to Fig. 19.4 – weld toe angle # 30 ° – length of doubling # 300 mm For length of doubling # 150 mm, )FR may be increased by two categories. 56 50 45 20 18 16 BKI - Rules for Hull - 2014
- 314. C Section 20 - Fatigue Strength20-16/20 Table 20.3 Catalogue of Details (Continued) D. Cruciform joints and T-joints Type No Joint configuration showing mode of fatigue cracking and stress F considered Description of joint Detail category )FR Steel Al D1 Cruciform or tee-joint K-butt welds with full penetration or with defined incomplete root penetration according to Section 19, Fig. 19.9. cruciform joint tee-joint 71 80 25 28 D2 Cruciform or tee-joint with transverse fillet weld, toe failure (root failure particularly for throat thickness a < 0,7 @ t , see joint type D3) cruciform joint tee-joint 63 71 22 25 D3 Welded metal in transverse load-carrying fillet weld at cruciform or tee - joint, root failure (based on stress range in weld throat). See also joint type No. D2 a $ t/3 a < t/3 Note Crack initiation at weld root 36 40 12 14 D4 Full penetration weld at the connection between a hollow section (e.g. pillar) and a plate, for tubular section for rectangular hollow section For t # 8 mm, )FR has to be decreased by one category. 56 50 20 18 D5 Fillet weld at the connection between a hollow section (e.g. pillar) and a plate, for tubular section for rectangular hollow section The stress is to be related to the weld sectional area. For t # 8 mm, )FR has to be decreased by one category. 45 40 16 14 D6 Continuous butt or fillet weld connecting a pipe penetrating through a plate d # 50 mm d > 50 mm Note For large diameters an assessment based on local stress is recommended. 71 63 25 22 BKI - Rules for Hull - 2014
- 315. Section 20 - Fatigue Strength C 20-17/20 Table 20.3 Catalogue of Details (Continued) E. Unwelded base material Type No Joint configuration showing mode of fatigue cracking and stress F considered Description of joint Detail category )FR Steel Al E1 Rolled or extruded plates and sections as well as seamless pipes, no surface or rolling defects 160 (m0 = 5) 71 (m0 = 5) E2 Plate edge sheared or machined cut by any thermal process with surface free of cracks and notches, corners broken or rounded. Stress increase due to geometry of cut-outs to be considered1) . 140 (m0 = 4) 40 (m0 = 4) E3 Plate edge not meeting the requirements of type E2, but free from cracks and severe notches. Machine cut or sheared edge: Manually thermally cut: Stress increase due to geometry of cut- outs to be considered. 125 (m0 = 3,5) 100 (m0 = 3,5) 36 (m0 = 3,5) 32 (m0 = 3,5) 1) Stress concentrations caused by an opening to be considered as follows: )Fmax = Kt @ )F; Kt = Notch factor according to Section 3, J. )Fmax = Nominal stress range related to net section alternatively direct determination of )Fmax from FE-calculation, especially in case of hatch openings or multiple arrangement of openings Partly based on Recommendations on Fatigue of Welded Components, reproduced from IIW document XIII-2151-07 / XV-1254-07, by kind permission of the International Institute of Welding. BKI - Rules for Hull - 2014
- 316. C Section 20 - Fatigue Strength20-18/20 Table 20.4 Various intersections 1) 1) Joint configuration Loads Location being at risk for cracks Description of joint Detail category )FR steel Non-watertight intersection without heel stiffener. For predominant longitudinal load only. 80 80 80 80 Watertight intersection without heel stiffener (without cyclic load on the transverse member) For predominant longitudinal load only. 71 71 71 71 With heel stiffener direct R # 150 connection R > 150 overlapping R # 150 connection R > 150 45 40 50 45 56 50 50 45 56 50 45 40 63 56 With heel stiffener and integrated bracket 45 56 56 63 With heel stiffener and integrated bracket and with backing bracket direct connection overlapping connection 50 56 63 56 63 50 71 With heel stiffener but considering the load transferred to the stiffener crack initiation at weld toe crack initiation at weld root stress increase due to eccentricity and shape cut out has to be observed 80 71 45 71 45 71 45 1) Additional stresses due to asymmetric sections have to be observed, see Section 3, L. 2) To be increased by one category, when longitudinal loads only BKI - Rules for Hull - 2014
- 317. Section 20 - Fatigue Strength C 20-19/20 Table 20.5 Examples of details Detail category )FR Steel 71 80 63 71 36 71 Descriptionofjoint Cruciformortee-jointK-buttwelds withfullpenetrationorwithdefined incompleterootpenetrationaccording toSection19,Fig.19.9. cruciformjoint tee-joint Cruciformortee-jointwithtransverse filletweld,toefailure(rootfailure particularlyforthroatthicknessa< 0,7t,seejointtypeD3) cruciformjoint tee-joint Weldedmetalintransverse load-carryingfilletweldatcruciform ortee-joint,rootfailure(basedon stressrangeinweldthroat).Seealso jointtypeNo.D2 R#150mm Inwayoftheroundedcornerofan openingwiththeradiusraminimum distancexfromtheedgetobekept (hatchedarea): x[mm]=15+0,175Ar[mm] 100mm#r#400mm Incaseofanellipticalroundingthe meanvalueofbothsemiaxestobe applied Jointconfigurationshowing modeoffatiguecrackingand stressFconsidered Type No. D1 D2 D3 C1 Descriptionofstructureor equipmentdetail Unstiffenedflangetowebjoint,tobe assessedaccordingtotypeD1,D2orD3, dependingonthetypeofjoint. Thestressinthewebiscalculatedusingthe forceFgintheflangeasfollows: Furthermore,thestressinlongitudinalweld directionhastobeassessedaccordingtotype B2–B4.Incaseofadditionalshearor bending,alsothehighestprincipalstressmay becomerelevantintheweb,seeB.1.4. Jointatstiffenedknuckleofaflange,tobe assessedaccordingtotypeD1,D2orD3, dependingonthetypeofjoint. Thestressinthestiffenerattheknucklecan normallybecalculatedasfollows: F=Fa2sin" Holderweldedinwayofanopeningandarranged paralleltotheedgeoftheopening. Notvalidforhatchcorner. Structureor equipmentdetail BKI - Rules for Hull - 2014
- 318. C Section 20 - Fatigue Strength20-20/20 Table 20.5 Examples of details (continued) Detail category )FR Steel 71 63 56 63 56 50 36 80 Descriptionofjoint tD<0,8t 0,8t<tD<1,5t tD>1,5t tD<0,8t 0,8t<tD<1,5t tD>1,5t 150<d<300mm d=diameter Partialpenetrationbuttweld; thestressistoberelatedtothe weldthroatsectionalarea, weldoverfillnottobetaken intoaccount Transversestiffenerwithfillet welds(applicableforshortand longstiffeners). Jointconfigurationshowing modeoffatiguecrackingand stressFconsidered Type No. C9 C9 A7 C7 Descriptionofstructureor equipmentdetail Circulardoublerplatewithmax.150mm diameter. DrainplugsaccordingtoDIN87721-1 (diameterabout190mm) Assesmentcorrespondingtodoublingplate. Drainplugswithpartialpenetrationbutt weld Thedetailcategoryisalsovalidfornotfully circumferentialweldedholders Forstiffenersloadedinbending)FRtobe downgradedbyonecategory. Structureor equipmentdetail BKI - Rules for Hull - 2014
- 319. Section 21 - Hull Outfit A, B 21-1/21 Section 21 Hull Outfit A. Partition Bulkheads 1. General Spaces,whicharetobeaccessiblefortheserviceoftheship,holdspacesandaccommodationspaces are to be gastight against each other. 2. Partition bulkheads between engine and boiler rooms 2.1 General 2.1.1 Boiler rooms generally are to be separated from adjacent engine rooms by bulkheads. Unless these bulkheads are watertight or tank bulkheads according to Section 11 or 12, the scantlings according to 2.2 are sufficient. 2.1.2 The bilges are to be separated from each other in such a way that no oil can pass from the boiler room bilge to the engine room bilge. Bulkhead openings are to have hinged doors. 2.1.3 Where a close connection between engine and boiler room is advantageous in respect of supervision and safety, complete bulkheads may be dispensed with, provided the conditions given in Rules for Machinery Installations, Volume III, are complied with. 2.2 Scantlings 2.2.1 The thickness of watertight parts of the partition bulkheads is not to be less than 6,0 mm. The thickness or the remaining parts may be 5 mm. 2.2.2 Platforms and decks below the boilers are to be made watertight; they are to be not less than 6,0 mm in thickness, and are to be well supported. 2.2.3 Stiffeners spaced 900 mm apart are to be fitted. The section modulus of the stiffeners is not to be less than: W = 12 @ R [cm3 ] R = unsupported span of stiffener [m]. Where the stiffener spacing deviates from 900 mm, the section modulus is to be corrected in direct proportion. B. Ceiling 1. Bottom ceiling 1.1 Where in the holds of general cargo ships a tight bottom ceiling is to be fitted from board to board, the thickness of a wooden ceiling shall not be less than 60 mm. 1.2 On single bottoms ceilings are to be removable for inspection of bottom plating at any time. 1.3 Ceilingsondoublebottomsaretobelaidonbattensnotlessthan12,5mmthickprovidingaclearspacefordrainage of water or leakage oil. The ceiling may be laid directly on the inner bottom plating, if embedded in preservation and sealing compound. 1.4 It is recommended to fit double ceilings under the hatchways. 1.5 The manholes are to be protected by a steel coaming welded around each manhole, fitted with a cover of wood or steel, or by other suitable means. BKI - Rules for Hull - 2014
- 320. B, C Section 21 - Hull Outfit21-2/21 2. Side ceiling, ceiling at tank bulkheads 2.1 In cargo holds of ordinary dry cargo ships, side ceiling is to be fitted in general. The side ceiling may be omitted if agreed by the Owner. The side ceilings shall extend from the upper turn of bilge or from tweendeck up to the lower edge of deck beam brackets. The clear distance between adjacent wooden battens shall not exceed 250-300 mm. The thickness shall, in general, not to be less than 50 mm. 2.2 Where tanks are intended to carry liquids at temperatures exceeding 40EC, their boundaries facing the cargo hold shall be fitted with a ceiling. At vertical walls, sparred ceilings are sufficient except in holds intended to carry grain. The ceiling may be dispensed with only with Owners' consent. C. Side Scuttles, Windows and Skylights 1. General 1.1 Sidescuttlesandwindows,togetherwiththeirglasses,deadlightsandstormcovers1) ,iffitted,shallbeofanapproved design and substantial construction. Non-metallic frames are not acceptable. 1.2 Sidescuttlesaredefinedasbeingroundorovalopeningswithanareanotexceeding0,16m2 .Roundorovalopenings having areas exceeding 0,16 m2 shall be treated as windows. 1.3 Windowsaredefinedasbeingrectangularopeningsgenerally,havingaradiusateachcornerrelativetothe window size and round or oval openings with an area exceeding 0,16 m2 . 1.4 Side scuttles to the following spaces shall be fitted with hinged inside deadlights: – spaces below freeboard deck – spaces within the first tier of enclosed superstructures – first tier deckhouses on the freeboard deck protecting openings leading below or considered buoyant in stability calculations Deadlights shall be capable of being closed and secured watertightiffittedbelow the freeboard deck and weathertight if fitted above. 1.5 Side scuttles shall not be fitted in such a position that their sills are below a line drawn parallel to the freeboard deck at side and having its lowest point 2,5% of the breadth (B), or 500 mm, whichever is the greatest distance, above the Summer Load Line (or Timber Summer Load Line if assigned), see Fig. 21.1. 1.6 Iftherequireddamagestabilitycalculationsindicatethatthesidescuttleswouldbecomeimmersedatany intermediate stage of flooding or the final equilibrium waterline, they shall be of the non-opening type. 1.7 Windows shall not be fitted in the following locations: – below the freeboard deck – in the first tier end bulkheads or sides of enclosed superstructures – in first tier deckhouses that are considered buoyant in the stability calculations 1.8 Side scuttles and windows at the side shell in the second tier shall be provided with hinged inside deadlights capable of being closed and secured weathertight if the superstructure protects direct access to an opening leading below or is considered buoyant in the stability calculations. 1.9 Side scuttles and windows in side bulkheads set inboard from the side shell in the second tier which protect direct accessbelowtospaceslistedin1.4shallbeprovidedwitheitherhingedinsidedeadlightsor,wheretheyareaccessible,permanently attached external storm covers which are capable of being closed and secured weathertight. 1) Deadlights are fitted to the inside of windows and side scuttles, while storm covers are fitted to the outside of windows, where accessible, and may be hinged or portable. BKI - Rules for Hull - 2014
- 321. Section 21 - Hull Outfit C 21-3/21 1.10 Cabin bulkheads and doors in the second tier and above separating side scuttles and windows from a direct access leading below or the second tier considered buoyant in the stability calculations may be accepted in place of deadlights or storm covers fitted to the side scuttles and windows. 1.11 Deckhouses situated on a raised quarter deck or on the deck of a superstructure of less than standard height may be regarded as being in the second tier as far as the requirements for deadlights are concerned, provided that the height of the raised quarter deck or superstructure is equal to or greater than the standard quarter deck height. 1.12 Fixed or opening skylights shall have a glass thickness appropriate to their size and position as required for side scuttlesandwindows.Skylightglassesinanypositionshallbeprotectedfrommechanicaldamageand,wherefittedinposition 1 or 2, shall be provided with permanently attached deadlights or storm covers. 1.13 Additional requirements for passenger vessels given in Section 29 have to be observed. 1.14 Additional requirements for oil tankers given in Section 24 have to be observed. 2. Design Load 2.1 The design load shall be in accordance with Section 4 and Section 16. 2.2 For ships with a length Lc equal to or greater than 100 m, loads in accordance with ISO 5779 and 5780 standard have to be calculated additionally. The greater value has to be considered up to the third tier. 2.3 Deviations and special cases are subject to separate approval. 3. Frames 3.1 The design has to be in accordance with ISO Standard 1751, 3903 and 21005 or any other recognised, equivalent National or International standard. 3.2 Variations from respective standards may require additional proof of sufficient strength by direct calculation or tests. This is to be observed for bridge windows in exposed areas (e.g. within forward quarter of ships length) in each case. 4. Glass panes 4.1 Glass panes have to be made of thermally toughened safety glass (TSG), or laminated safety glass made of TSG. The ISO standards 614, 1095 and 3254 are to be observed. Fig.21.1 Arrangement of side scuttles 4.2 The glass thickness for windows and side scuttles has to be determined in accordance with the respective ISO standards 1095 and 3254 or any other equivalent national or international standard, considering the design loads given in 2. For sizes deviating from the standards, the formulas given in ISO 3903 may be used. BKI - Rules for Hull - 2014
- 322. C, D Section 21 - Hull Outfit21-4/21 4.3 Heated glass panes have to be in accordance with ISO 3434. 4.4 An equivalent thickness (ts) of laminated toughened safety glass is to be determined from the following formula: ts = 5. Tests Windows and side scuttles have to be tested in accordance with the respective ISO standards 1751 and 3903. D. Scuppers, Sanitary Discharges and Freeing Ports 1. Scuppers and sanitary discharges 1.1 Scuppers sufficient in number and size to provide effective drainage of water are to be fitted in the weather deck and in the freeboard deck within weathertight closed superstructures and deckhouses. Cargo decks and decks within closed superstructuresaretobedrainedtothebilge.Scuppersfromsuperstructuresanddeckhouseswhicharenotclosedweathertight are also to be led outside. 1.2 Scuppers draining spaces below the summer load line, are to be connected to pipes, which are led to the bilges and are to be well protected. 1.3 Wherescupperpipesareledoutsidefromspacesbelowthefreeboarddeckandfromweathertightclosedsuperstructures and deckhouses, they are to be fitted with non-return valves of automatic type, which can be operated from a position always accessible and above the freeboard deck. Means showing whether the valves are open or closed (positive means of closing) are to be provided at the control position. 1.4 Where the vertical distance from the summer load waterline to the inboard end of the discharge pipe exceeds 0,01 L, the discharge may have two automatic non-return valves without positive means of closing, provided that the inboard valve is always accessible for examination, i.e., the valve is to be situated above the tropical or subdivision load line. 1.5 Where the vertical distance mentioned under 1.4 exceeds 0,02 L, a single automatic non-return valve, without positive means of closing may be accepted. This relaxation is not valid for compartments below the freeboard deck of ships, for which a flooding calculation in the damaged condition is required. 1.6 Scuppers and discharge pipes originating at any level and penetrating the shell either more than 450 mm below the freeboard deck or less than 600 mm above the summer load water line are to be provided with a non-return valve at the shell. This valve, unless required by 1.3, may be omitted if a heavy gauge discharge pipe is fitted. 1.7 Requirements for seawater valves related to operating the power-plant shall be observed see Rules for Machinery Installations, Volume III, Section 11, I.3. 1.8 All valves including ship side valves required under 1.2 to 1.7 are to be of steel, bronze or other approved ductile material. Ordinary casts iron is not acceptable. Pipe lines are to be of steel or similar material ( see Rules for Machinery Installations, Volume III, Section 11). 1.9 Scuppersandsanitarydischargesshouldnotbefittedabovethelowestballastwaterlineinwayoflifeboatlaunching positions or means for preventing any discharge of water into the life boats are to be provided for. The location of scuppers and sanitary discharges is also to be taken into account when arranging gangways and pilot lifts. 2. Freeing ports 2.1 Where bulwarks on exposed portions of freeboard and/or superstructure decks form wells, ample provision is to be made for rapidly freeing the decks of water. 2.2 Except as provided in 2.3 to 2.5 the minimum freeing port area on each side of the ship for each well on the freeboard deck of a ship of type "B" is to be determined by the following formulae in cases where the sheer in way of the well is standard or greater than standard : A = 0,7 + 0,035 R [m2 ] for R < 20 m BKI - Rules for Hull - 2014
- 323. Section 21 - Hull Outfit D, E 21-5/21 = 0,07 R [m2 ] for R > 20 m R = length of bulwark [m] Rmax = 0,7 L The minimum area for each well on superstructure decks shall be one half of the area obtained by the formulae. If the bulwark is more than 1,2 m in average height the required area is to be increased by 0,004 m2 per metre of length of well for each 0,1 m difference in height. If the bulwark is less than 0,9 m in average height, the required area may be decreased accordingly. 2.3 In ships with no sheer the area calculated according to 2.2 is to be increased by 50%. Where the sheer is less than the standard the percentage shall be obtained by linear interpolation. 2.4 In ships of type "B with reduced freeboard" the freeing port area on the exposed freeboard deck is to be obtained as follows : - Where a combination of open rail and rigid bulwark is fitted, the length of the open rail is to be at least 50% of the length of the exposed part of the freeboard deck. - Where a continuous bulwark is fitted, the freeing port area is to be 25% of the total area of the bulwarks, where the freeboard is reduced by not more than 60% of the difference between B and A tables. Where the freeboard is reduced by more than 60% the area is to be not less than 33% of the total area of the bulwarks. 2.5 Where a ship is fitted with a trunk on the freeboard deck, which will not be take into account when calculating thefreeboard,orwherecontinuousorsubstantiallycontinuoushatchwaysidecoamingsarefittedbetweendetachedsuperstructures the minimum area of the freeing port openings is to be determined from Table 21.1. 2.6 In ships having open superstructures, adequate freeing ports are to be provided which guarantee proper drainage. 2.7 Where trunks are taken into account when calculating the freeboard an open rail is to be fitted in way of the trunk for at least 50% of the length of the trunk. As an equivalent, a continuous bulwark can be fitted with a continuous slot of 33% of the bulwark area. 2.8 The lower edges of the freeing ports shall be as near to the deck as practicable. Two thirds of the freeing port area required shall be provided in the half of the well nearest to the lowest point of the sheer curve. Table 21.1 - Minimum area of freeing ports Breadth of hatchway or trunk in relation to B [%] Area of freeing ports in relation to the total area of the bulwark [%] 1) (each side separately) 40 or less 75 or more 20 10 1) The area of freeing ports at intermediate breadth is to be obtained by linear interpolation 2.9 All such openings in the bulwarks shall be protected by rails or bars spaced approximately 230 millimeters apart. Ifshuttersarefitted to freeing ports, ample clearance shallbe provided to preventjamming. Hingesshallhavepinsorbearings of non-corrodible material. 2.10 Oncontainershipswithcontinuouslongitudinalhatchcoamings,wherewatermayaccumulatebetweenthe transverse coamings, freeing ports are to be provided at both sides, with a minimum sectional area Aq of : Aq = 0,07 @ bQ [m2 ] bQ = breadth of transverse box girder [m] E. Air Pipes, Overflow Pipes, Sounding Pipes 1. Each tank is to be fitted with air pipes, overflow pipes and sounding pipes. The air pipes are in general to be led BKI - Rules for Hull - 2014
- 324. E Section 21 - Hull Outfit21-6/21 to above the exposed deck. For the arrangement and scantlings of pipes see also Rules for Machinery Installations, Volume III, Section 11,R. The height from the deck of the point where the water may have access is to be at least 760 mm on the freeboard deck and 450 mm on a superstructure deck. 2. Suitable closing appliances are to be provided for air pipes, overflow pipes and sounding pipes, see also Rules for Machinery Installations, Volume III, , Section 11, R. Where deck cargo is carried, the closing appliances are to be readily accessible at all times. In ships for which flooding calculations are to be made, the ends of the air pipes are to be above the damage waterline in the flooded condition. Where they immerge at intermediate stages of flooding, these conditions are to be examined separately. 3. Closely under the inner bottom or the tank top, holes are to be cut into floor plates and side girders as well as into beams, girders, etc., to give the air free access to the air pipes. Besides, all floor plates and side girders are to be provided with limbers to permit the water or oil to reach the pump suctions. 4. Sounding pipes are to be extended to directly above the tank bottom. The shell plating is to be strengthened by thicker plates or doubling plates under the sounding pipes. 5. Special strength requirements for fore deck fittings 5.1 General The following strength requirements are to be observed to resist green sea forces for the items given below, located within the forward quarter length: – air pipes, ventilator pipes and their closing devices Exempted from these requirements are air pipes, ventilator pipes and their closing devices of the cargo venting systems and the inert gas systems of tankers. 5.2 Application For ships that are contracted for construction on or after 1st January 20042) on the exposed deck over the forward 0,25 L, applicable to: – all ship types of seagoing service of length 80 m or more, where the height of the exposed deck in way of the item is less than 0,1 L or 22 m above the summer load waterline, whichever is the lesser 5.3 Applied loading for air pipes, ventilator pipes and their closing devices 5.3.1 The pressures p [kN/m2 ] acting on air pipes, ventilator pipes and their closing devices may be calculated from: p = [kN/m2 ] D = density of sea water (1,025 t/m3 ) V = velocity of water over the fore deck- = 13,5m/sec for d #0.5 # d1 = m/sec for 0.5 d1 # d # d1 d = distance from summer load waterline to exposed deck d1 = 0.1L or 22m whichever is the lesser Cd = shape coefficient = 0,5 for pipes = 0,8 for an air pipe or ventilator head of cylindrical form with its axis in the vertical direction = 1,3 for air pipes or ventilator heads 2) For ships contracted for construction prior to 1st January 2004 refer to IACS UR S27 para 2.2. BKI - Rules for Hull - 2014
- 325. Section 21 - Hull Outfit E 21-7/21 Cs = slamming coefficient = 3,2 Cp = protection coefficient = 0,7 for pipes and ventilator heads located immediately behind a breakwater or forecastle = 1,0 elsewhere and immediately behind a bulwark 5.3.2 Forces acting in the horizontal direction on the pipe and its closing device may be calculated from 5.3.1 using the largest projected area of each component. 5.4 Strength requirements for air pipes, ventilator pipes and their closing devices 5.4.1 Bending moments and stresses in air and ventilator pipes are to be calculated at critical positions: – at penetration pieces – at weld or flange connections – at toes of supporting brackets Bending stresses in the net section are not to exceed 0,8@Fy, where Fy is the specified minimum yield stress or 0,2 % proof stress of the steel at room temperature. Irrespective of corrosion protection, a corrosion addition to the net section of 2,0 mm is then to be applied. 5.4.2 Forstandardairpipesof760mmheightclosedbyheadsofnotmorethanthetabulatedprojectedarea,pipe thicknesses and bracket heights are specified in Table 21.2. Where brackets are required, three or more radial brackets are to be fitted. Brackets are to be of gross thickness 8 mm or more, of minimum length 100 mm, and height according to Table 21.2 but need not extend over the joint flange for the head. Bracket toes at the deck are to be suitably supported. 5.4.3 For other configurations, loads, according to 5.3 are to be applied, and means of support determined in order to comply with the requirements of 5.4.1. Brackets, where fitted, are to be of suitable thickness and length according to their height. Pipe thickness is not to be taken less than as indicated in Rules for Machinery Installations, Volume III, Section 11, Table 11.20a and 11.20b. 5.4.4 For standard ventilators of 900 mm height closed by heads of not more than the tabulated projected area, pipe thicknesses and bracket heights are specified in Table 21.3. Brackets, where required are to be as specified in 5.4.2. 5.4.5 Forventilatorsofheightgreaterthan900mm,bracketsoralternativemeansofsupportaretobespecially considered. Pipe thickness is not to be taken less than as indicated in Rules for Machinery Installations, Volume III, Section 11, Table 11.20a and 11.20b. 5.4.6 All component part and connectionsofthe air pipe or ventilator are to be capable of withstanding the loads defined in 5.3. 5.4.7 Rotating type mushroom ventilator heads are unsuitable for application in the areas defined in 5.2. Table 21.2 - 760 mm air pipe thickness and bracket standards Nominal pipe diameter [mm] Minimum fitted 1) gross thickness [mm] Maximum projected area of head [cm2 ] Height2) of brackets [mm] 65A 6.0 –– 480 80A 6.3 –– 460 100A 7.0 –– 380 125A 7.8 –– 300 150A 8.5 –– 300 175A 8.5 –– 300 200A 8.5 3) 1900 300 3) 250A 8.5 3) 2500 300 3) 300A 8.5 3) 3200 300 3) 350A 8.5 3) 3800 300 3) BKI - Rules for Hull - 2014
- 326. E, F Section 21 - Hull Outfit21-8/21 400A 8.5 3) 4500 300 3) 1) See IACS Unified Interpretation LL 36.c 2) Brackets see 5.4.2 need not extend over the joint flange for the head. 3) Brackets are required where the as fitted (gross) thickness is less than 10,5 mm, or where the tabulated projected head area is exceeded. Note: For other air pipe heights, the relevant requirements of 5.4 are to be applied Table 21.3 - 900 mm ventilator pipe thickness and bracket standards Nominal pipe diameter [mm] Minimum fitted gross thickness [mm] Maximum projected area of head [cm2 ] Height of brackets [mm] 80A 6,3 –– 460 100A 7,0 –– 380 150A 8,5 –– 300 200A 8,5 550 –– 250A 8,5 880 –– 300A 8,5 1200 –– 350A 8,5 2000 –– 400A 8,5 2700 –– 450A 8,5 3300 –– 500A 8,5 4000 –– Note: For other ventilator heights, the relevant requirements of 5.4 are to be applied. F. Ventilators 1. General 1.1 The height of the ventilator coamings on the exposed freeboard deck, quarter deck and on exposed superstructure decks in the range 0,25 L from F.P. is to be at least 900 mm. 1.2 On exposed superstructure decks abaft 0,25 L from F.P. the coaming height is not to be less than 760 mm. 1.3 Ventilators of cargo holds are not to have any connection with other spaces. 1.4 The thickness of the coaming plates is to be 7,5 mm where the clear opening sectional area of the ventilator coamings is 300 cm2 or less, and 10 mm where the clear opening sectional area exceeds 1600 cm2 . Intermediate values are to be determined by direct interpolation. A thickness of 6 mm will generally be sufficient within not permanently closed superstructures. 1.5 The thickness of ventilator posts should be at least equal to the thickness of coaming as per 1.4. 1.6 The wall thickness of ventilator posts of a clear sectional area exceeding 1600 cm2 is to be increased according to the expected loads. 1.7 Generally, the coamings and posts shall pass through the deck and shall be welded to the deck plating from above and below. Where coamings or posts are welded onto the deck plating, fillet welds of a = 0,5 @ t0, subject to Section 19, B.3.3 should be adopted for welding inside and outside. 1.8 Coamings and posts particularly exposed to wash of sea are to be efficiently connected with the ship's structure. 1.9 Coamings of a height exceeding 900 mm are to be specially strengthened. 1.10 Where the thickness of the deck plating is less than 10 mm, a doubling plate or insert plate of 10 mm thickness BKI - Rules for Hull - 2014
- 327. Section 21 - Hull Outfit F, G 21-9/21 is to be fitted. Their side lengths are to be equal to twice the length or breadth of the coaming. 1.11 Wherebeams are pierced by ventilatorcoamings,carlingsofadequatescantlingsaretobefittedbetweenthebeams in order to maintain the strength of the deck. 2. Closing appliances 2.1 Inlet and exhaust openings of ventilation systems are to be provided with easily accessible closing appliances, which can be closed weathertight against wash of the sea. ln ships of not more than 100 m in length, the closing appliances are to be permanently attached. In ships exceeding 100 m in length, they may be conveniently stowed near the openings to which they belong. 2.2 Forventilatorpostswhichexceed4,5minheightabovethefreeboarddeckorraisedquarterdeckandaboveexposed superstructuredecksforwardof0,25L fromF.P. andforventilatorpostsexceeding2,3minheightaboveexposedsuperstructure decks abaft 0,25 L from F.P. closing appliances are required in special cases only. 2.3 For the case of fire draught-tight fire dampers are to be fitted. 3. For Special strength requirements for fore deck fittings, see E.5. G. Stowage of Containers 1. General 1.1 All parts for container stowing and lashing equipment are to comply with the "Rules for the Stowage and Lashing of Containers Aboard Ships". All parts which are intended to be welded to the ship's hull, including hatchcovers, are to be made of materials complying with and tested in accordance with the Rules for Materials, Volume V. 1.2 Allequipmentondeckandintheholdsessentialformaintainingthesafetyoftheshipandwhicharetobeaccessible at sea, e.g. fire fighting equipment, sounding pipes etc., should not be made inaccessible by containers or their stowing and lashing equipment. 1.3 Fortransmitting the forces fromthe container stowing and lashing equipment into the ship's hull adequatewelding connections and local reinforcements of structural members are to be provided (see also 2. and 3.). 1.4 The hatchway coamings are to be strengthened in way of the connections of transverse and longitudinal struts of cell guide systems. The cell guide systems are not permitted to be connected to projecting deck plating edges in way of the hatchways. Any flame cutting or welding should be avoided, particularly at the deck rounding in the hatchway corners. 1.5 Where inner bottom, decks, or hatchcovers are loaded with containers, adequate substructures, e.g. carlings, half heightgirdersetc.,aretobeprovidedandtheplatethicknessistobeincreased whererequired.Forwelded-inparts,seeSection 19, B.2. 2. Load assumptions 2.1 The scantlings of the local ship structures and of the container substructures are to be determined on the basis of the Containers Stowage and Lashing Plans. 2.2 For determining scantlings the following design forces are to be used which are assumed to act simultaneously in the centre of gravity of a stack : ship's transverse (y-) direction: 0,5 g @ G [kN] ship's vertical (z-) direction: (1 + av) g @ G [kN] G = stack mass [t] BKI - Rules for Hull - 2014
- 328. G, H, J Section 21 - Hull Outfit21-10/21 av = see Section 4, C.1.1. 3. Permissible stresses 3.1 For hatchway covers in pos. 1 and 2 loaded with containers, the permissible stresses according to Section 17, C.2. are to be observed. 3.2 The stresses in local ship structures and in substructure for containers as well as for cell guide systems and lashing devices in the hatch covers of cargo decks are not to exceed the following values: Fb = [N/mm2 ] J = [N/mm2 ] Fv = < [N/mm2 ] ReH = minimum nominal upper yield point of the material. 3.3 For dimensioning the double bottom in case of single point loads due to 20'- or 40'-containers, see Section 8, B.8.2. 3.4 Where other structural members of the hull, e.g. frames, deck beams, bulkheads, hatchway coamings, bulwark stays etc. are subjected to loads from containers, cell guide systems and container lashing devices, these members are to be strengthened wherever necessary so that the actual stresses will not exceed those upon which the formulae in the respective Sections are based. H. Lashing Arrangements Lashingeyesandholesaretobearrangedinsuchawayastonotundulyweakenthestructuralmembersofthehull.Inparticular wherelashingsareattachedtoframes,theyaretobesoarrangedthatthebendingmomentintheframesisnotundulyincreased. Where necessary, the frame is to be strengthened. J. Car Decks 1. General 1.1 These Rules apply to movable as well as to removable car decks not forming part of the ship's structure. 1.2 The following information should be included in the plans to be submitted for approval : - Scantlings of the car decks - Masses of the car decks - Number and masses of cars intended to be stowed on the decks - Wheel loads and distance of wheels - Connection of the car decks to the hull structure - Moving and lifting gear of the car decks. 1.3 Car decks in accordance with these requirementsmaybemadeofhullstructuralsteel or of the following materials: - Structural steel R St 37-2 (Fe 360 B) and St 52-3 (Fe 510 D1) - Seawater resisting aluminium alloys 2. Design loads 2.1 For determining the scantlings of remaining component parts of the decks, the following loads are to be used: BKI - Rules for Hull - 2014
- 329. Section 21 - Hull Outfit J 21-11/21 - Uniformly distributed load resulting from the mass of the deck and maximum number of cars to be carried. This load is not to be taken less than 2,5 [kN/m2 .]. - Wheel load P Where all wheels of one axle are standing on a deck girder or a deck beam, the axle load is to be evenly distributed on all wheels. Where not all of the wheels of one axle are standing on a deck girder or a deck beam, the following wheel loads are to be used: P = 0,5 x axle load for 2 wheels per axle = 0,3 x axle load for 4 wheels per axle = 0,2 x axle load for 6 wheels per axle. Where no data is available, P is to be taken as 25 [kN]. 2.2 For determining the scantlings of the suspensions, the increased wheel load in case of four and six wheels per axle as per 2.1 need not be considered. 3. Plating 3.1 The thickness of the plating is to be determined accordingto the formulae as per Section 7, B.2. Where aluminium alloy is used, the thickness is to be determined as per Section 2, D.1. 3.2 The thickness of plywood is to bedeterminedtaking into account a safety factor of 6 against the minimumultimate strength of the material. Where plywood plates, supported on two sides only, are subjected to single loads, 1,45 times the unsupported span may be taken as effective width of the plating. 4. Permissible stresses 4.1 In steel stiffeners and girders as well as in the steel structural elements of the suspensions, subjected to loads as per 2. including the acceleration factor av according to Section 4, C.1.1 the following permissible stresses are to be observed: Normal and bending stresses (tension and compression): F < [N/mm2 ] Sheer stresses: J < [N/mm2 ] Combined stresses: Fv = # [N/mm2 ] k = material factor according to Section 2, B.2. = 0,72 for Fe 510 D1 (St 52-3) = 1,0 for Fe 360 B (R St 37-2) 4.2 Wherealuminiumalloysareused,thepermissiblestressesmaybederivedfrommultiplyingthepermissiblestresses specified for ordinary hull structural steel by the factor 1/kAR (kAR = material factor for aluminium according to Section 2, D.1.). 5. Permissible deflection 5.1 The deflection of girders subjected to loads stipulated under 2. is not to exceed: f = R = unsupported span of girder. 5.2 An adequate safety distance should be maintained between the girders of a loaded deck and the top of car stowed on the deck below. BKI - Rules for Hull - 2014
- 330. J, K, L Section 21 - Hull Outfit21-12/21 6. Buckling The buckling strength of girders is to be proved according to Section 3, F., if required. K. Life Saving Appliances 1. It is assumed that for the arrangement and operation of life boats and other life saving appliances the regulations of SOLAS 74 or those of the competent Authority are complied with. 2. The design appraisal and testing of life boats with their launching appliances and of other life saving appliances are not part of Classification. However, approval of the hull structure in way of the launching appliances taking into account the forces from the above appliances is part of classification. Part of Classification also is the survey of the life saving appliances and their launching appliances with regard to their proper condition and functioning within the scope of the class renewal surveys. L. Signal and Radar Masts 1. General 1.1 Drawings of masts, mast substructures and hull connections are to be submitted for approval. 1.2 Loosecomponentpartsaretocomplywiththe"RegulationsfortheConstructionandSurveyofLiftingAppliances". They are to be tested by BKI. 1.3 Other masts than covered by 2. and 3. as well as special designs, shall as regards dimensions and construction in each case be individually agreed with BKI. 2. Single tubular masts The following requirements applytotubular or equivalent rectangular sections made of steel with an ultimate tensile strength of 400 N/mm², which are designed to carry only signals (navigation lanterns, flag and day signals). 2.1 Stayed masts 2.1.1 Stayed masts may be constructed as simply supported masts (rocker masts) or may be supported by one or more decks (constrainedt masts). 2.1.2 The diameterofstayed steelmastsintheuppermosthousingistobeatleast20mmforeach1mlengthofhounding. The length of the mast top above the hounds is not to exceed 1/3 Rw (Rw denotes the hounding [m]). 2.1.3 Mast according to 2.1.2 may be gradually tapered towards the hounds to 75% of the diameter at the uppermost housing. The plate thickness is not to be less than 1/70 of the diameter or at least 4 mm, see 4.1. 2.1.4 Wire ropes for shrouds are to be thickly galvanized. It is recommended to use wire ropes composed of a minimum number of thick wires, as for instance a rope construction 6 x7 with a tensile breaking strength of 1570 N/mm2 . 2.1.5 Where masts are stayed forward and aft by one shroud on each side of the ship, steel wire ropes are to be used with a tensile breaking strength of 1570 N/mm2 according to Table 21.4. Table 21.4 - Rope and sackles of stayed steel masts h [m] 6 8 10 12 14 16 Rope diameter [mm] 14 16 18 20 22 24 Nominal size of shackle, rigging screw, rope socket 2,5 3 4 5 6 8 h = height of hound over the hauling of the shrouds BKI - Rules for Hull - 2014
- 331. Section 21 - Hull Outfit L 21-13/21 2.1.6 Where steel wire ropes according to Table 21.2 are used, the following conditions apply: b > 0,3 h 0,15 h < a < b a = the distance of the hauling points of the shrouds from the transverse section through the hound. b = the distance of the hauling points of the shrouds from the longitudinal section through the hound. Alternative arrangements of staying are to be of equivalent stiffness 2.2 Unstayed masts 2.2.1 Unstayed masts may be completely constrained in the uppermost deck or be supported by two or more decks. (In general, the fastenings of masts to the hull of a ship should extend over at least one deck height). 2.2.2 The scantlings for unstayed steel masts are given in the Table 21.5 Table 21.5 - Dimensions of unstayed steel masts Length of mast Rm [m] 6 8 10 12 14 Dxt [mm] 160 x@4 220 x 4 290 x 4,5 360 x 5,5 430 x 6,5 Rm = length of mast from uppermost support to the top D = diameter of mast at uppermost support t = plate thickness of mast 2.2.3 The diameter of masts may be gradually tapered to D/2 at the height of 0,75 Rm. 3. Box girder and frame work masts 3.1 For dimensioning the dead loads, acceleration forces and wind loads are to be considered. 3.2 Where necessary additional loads e. g. loads caused by the sea fastening of crane booms or tension wires are also to be considered. 3.3 Thedesignloadsfor3.1and3.2aswellastheallowablestressescanbetakenfromthe"RegulationsfortheConstruction and Survey of Lifting Appliances." 3.4 Single tubular masts mounted on the top may be dimensioned according to 2. 3.5 In case of thin walled boxgirder masts stiffeners and additional buckling stiffeners may be necessary. 4. Structural details 4.1 Steelmastsclosedall-roundshallhaveawallthicknessofatleast4mm.Formastsnotclosedall-roundtheminimum wall thickness is 6 mm. For masts used as funnels a corrosion addition of at least 1 mm is required. 4.2 The ship’s side foundations are to be dimensioned in accordance with the acting forces. 4.3 Doublingplatesatmastfeetarepermissibleonlyforthetransmissionofcompressiveforcessincetheyaregenerally not suitable for the transmission of tensile forces or bending moments. 4.4 In case of tubular constructions all welded fastenings and connections shall be of full penetration weld type. 4.5 If necessary, slim tubes are to be additionally supported in order to avoid vibrations. 4.6 The dimensioning normally does not require a calculation of vibrations. However, in case of undue vibrations accuring during the ship’s trial a respective calculation will be required. 4.7 For determining scantlings of masts made from aluminium or austenitic steel, the requirements given in Section 2, D. and E. apply. BKI - Rules for Hull - 2014
- 332. L, M, N Section 21 - Hull Outfit21-14/21 4.8 Atmastssolidsteelladdershavetobefixedatleastupto 1,50mbelowtop,iftheyhavetobeclimbedforoperational purposes. Above them, suitable handgrips are neccessary. 4.9 If possible from the construction point of view, ladders should be at least 0,30 m wide. The distance between the rungs shall be 0,30 m. The horizontal distance of the rung centre from fixed parts shall not be less than 0,15 m. The rungs shall be aligned and be made of square steel bars 20/20 edge up. 4.10 Platforms on masts which have to be used for operational reasons, shall have a rail of at least 0,90 m in height with one intermediate bar. Safe access from the mast ladders to the platform is to be provided. 4.11 On masts additional devices have to be installed consisting of foot, back, and hand rings enabling safe work in places of servicing and maintenance. M. Loading and Lifting Gear 1. The design appraisal and testing of loading and lifting gear on ships are not part of Classification. 2. However approval of the hull structure in way of loading and lifting gear taking into account the forces from the gear is part of Classification. Note WhereBKIisentrustedwiththejudgementofloadingandliftinggears,Society's Regulations for the ConstructionandSurvey of Lifting Appliances are to be applied. N. Access to Cargo Area of Oil Tankers and Bulk Carriers Special measures are to be taken for safe access to and working in spaces in and forward of the cargo area of tankers and bulk carriers for the purpose of maintenance and carrying out surveys. Note This requirement is considered to be complied with where the SOLAS, Chapter II-1, Reg. 3-6, is adhered to Abstract of this Regulation : 1. Safe access to cargo holds, cargo tanks, ballast tanks and other spaces 1.1 Safe access to cargo holds, cofferdams, ballast tanks, cargo tanks and other spaces in the cargo area shall be direct from the open deck and such as to ensure their complete inspection. Safe access to double bottom spaces may be from apump-room,deepcofferdam,pipetunnel,cargohold,doublehullspaceorsimilarcompartmentnotintendedforthecarriage of oil or hazardous cargoes. 1.2 Tanks,andsubdivisionsoftanks,havingalengthof35mormore, shallbe fittedwithatleasttwoaccess hatchways and ladders, as far apart as practicable. Tanks less than 35 m in length shall be served by at least one access hatchway and ladder. When a tank is subdivided by one or more swash bulkheads or similar obstructions which do not allow ready means of access to the other parts of the tank, at least two hatchways and ladders shall be fitted. 1.3 Each cargo hold shall be provided with at least two means of access as far apart as practicable. In general, these accesses should be arranged diagonally, for example one access near the forward bulkhead on the port side, the other one near the aft bulkhead on the starboard side. 1.4 Where a permanent means of access may be susceptible to damage during normal cargo loading and unloading operations or where it is impracticable to fit permanent means of access, the Administration may allow, in lieu thereof, the provisionofmovableorportablemeansofaccess,asspecifiedintheTechnicalprovisions,providedthatthemeansofattaching, rigging, suspending or supporting the portable means of access forms a permanent part of the ship's structure. All portable equipment shall be capable of being readily erected or deployed by ship's personnel. 2. Definitions BKI - Rules for Hull - 2014
- 333. Section 21 - Hull Outfit N 21-15/21 2.1 Rung Rung means the step of a vertical ladder or step on the vertical surface. 2.2 Tread Tread means the step of an inclined ladder or step for the vertical access opening. 2.3 Flight of an inclined ladder Flight of an inclined ladder means the actual stringer length of an inclined ladder. For vertical ladders, it is the distance between the platforms. 2.4 Stringer Stringer means: – the frame of a ladder; or – the stiffened horizontal plating structure fitted on the side shell, transverse bulkheads and/or longitudinal bulkheads in the space. For the purpose of ballast tanks of less than 5 m width forming double side spaces, the horizontal plating structure is credited as a stringer and a longitudinal permanent means of access, if it provides a continuous passage of 600 mm or more in width past frames or stiffeners on the side shell or longitudinal bulkhead. Openings in stringer plating utilized as permanent means of access shall be arranged with guard rails or grid covers to provide safe passage on the stringer or safe access to each transverse web. 2.5 Vertical ladder Vertical ladder means a ladder of which the inclined angle is 70º and over up to 90º. A vertical ladder shall not be skewed by more than 2º. 2.6 Overhead obstructions Overhead obstructions mean the deck or stringer structure including stiffeners above the means of access. 2.7 Distance below deck head Distance below deck head means the distance below the plating. 2.8 Cross deck Cross deck means the transverse area of the main deck which is located inboard and between hatch coamings. 3. Technical provisions 3.1 Structural members subject to the close-up inspections andthickness measurementsof the ship's structure, except those in double bottom spaces, shall be provided with a permanent means of access to the extent as specified in Table 21.6 and Table 21.7, as applicable. For oil tankers and wing ballast tanks of ore carriers, approved alternative methods may be used in combination with the fitted permanent means of access, provided that the structure allows for its safe and effective use. 3.2 Permanent means of access should as far as possible be integral to the structure of the ships, thus ensuring that they are robust and at the same time contributing to the overall strength of the structure of the ship. 3.3 Elevated passageways forming sections of a permanent means of access, where fitted,shallhave a minimum clear width of 600 mm, except for going around vertical webs where the minimum clear width may be reduced to 450 mm, and have guard rails over the open sideoftheir entirelength.Slopingstructures providing part of the access shall be of a non-skid construction. Guard rails shall be 1,000 mm in height and consist of a rail and an intermediate bar 500 mm in height and of substantial construction. Stanchions shall be not more than 3 m apart. 3.4 Access to permanent means of access and vertical openings from the ship's bottom shall be provided by means of easily accessible passageways, ladders or treads. Treads shall be provided with lateral support for the foot. Where the rungs of ladders are fitted against a vertical surface, the distance from the centre of the rungs to the surface shall be at least 150 mm. Where vertical manholes are fittedhigherthan600mmabovethewalkinglevel, access shall be facilitated by means of treads and hand grips with platform landings on both sides. 3.5 Permanent inclined ladders shall be inclined at an angle of less than 70º. There shall be no obstructions within BKI - Rules for Hull - 2014
- 334. N Section 21 - Hull Outfit21-16/21 750 mm of the face of the inclined ladder, except that in way of an opening this clearance may be reduced to 600 mm. Resting platforms of adequate dimensions shall be provided, normally at a maximum of 6 m vertical height. Ladders and handrails shall be constructed of steel or equivalent material of adequate strength and stiffness and securely attached to the structure by stays. The method of support and length of stay shall be such that vibration is reduced to a practical minimum. In cargo holds, ladders shall be designed and arranged so that cargo handling difficulties are not increased and the risk of damage from cargo handling gear is minimized Table 21.6 Means of access for ballast and cargo tanks of oil tankers Water ballast tanks except those specified in the right column, and cargo oil tanks Water ballast wing tanks of less than 5 m width forming double side spaces and their bilge hopper sections Access to the underdeck and vertical structure For tanks of which the height is 6 m and over containing internal structures, permanent means of access shall be provided in accordance with 1. to 6. : For double side spaces above the upper knuckle point of the bilge hopper sections, permanent means of access are to be provided in accordance with 1. to 3. : 1. continuous athwartshippermanentaccess arranged at each transverse bulkhead on the stiffened surface, at aminimumof1,6mtoamaximumof3mbelowthedeck head; 1. wheretheverticaldistancebetweenhorizontal uppermost stringer and deck head is 6 m or more, one continuous longitudinalpermanentmeansofaccessshallbeprovided for the full length of the tank with a means to allow passingthroughtransversewebsinstalledataminimum of 1,6 m to a maximum of 3 m below the deck head with a vertical access ladder at each end of the tank; 2. at least one continuous longitudinal permanent means ofaccessat each side of the tank. One of these accesses shall be at a minimum of 1,6 m to a maximum of 6 m belowthedeckheadandtheothershallbeataminimum of 1,6 m to a maximum of 3 m below the deck head; 2. continuous longitudinal permanent means of access, which are integrated in the structure, at a vertical distance not exceeding 6 m apart; and 3. access between the arrangements specified in 1. and 2. and from the main deck to either 1. or 2.; 3. platedstringersshall,asfaraspossible,bein alignment with horizontal girders of transverse bulkheads 4. continuous longitudinal permanent means of access which are integrated in the structural member on the stiffenedsurfaceofalongitudinalbulkhead,inalignment, where possible, with horizontal girders of transverse bulkheadsaretobeprovidedforaccesstothetransverse webs unless permanent fittings are installed at the uppermost platform for use of alternative means, as defined in 3.9 for inspection at intermediate heights; 5. forshipshavingcross-tieswhichare6mormore above tank bottom, a transverse permanent means of access on the cross-ties providing inspection of the tie flaring brackets at both sides of the tank, with access fromone ofthelongitudinalpermanentmeansofaccessin4.;and 6. alternative means as defined in 3.9 may be provided forsmallshipsasanalternativeto4.forcargooiltanks of which the height is less than 17 m. BKI - Rules for Hull - 2014
- 335. Section 21 - Hull Outfit N 21-17/21 Table 21.6 Means of access for ballast and cargo tanks of oil tankers (continued) Water ballast tanks except those specified in the right column, and cargo oil tanks Water ballast wing tanks of less than 5 m width forming double side spaces and their bilge hopper sections Access to the underdeck and vertical structure For tanks of which the height is less than 6 m, alternative means as defined in 3.9 or portable means may be utilized in lieu of the permanent means of access. Forbilgehoppersectionsofwhichtheverticaldistancefrom the tank bottom to the upper knuckle point is 6 m and over, onelongitudinalpermanentmeansofaccessshallbeprovided forthefulllengthofthetank.Itshallbeaccessiblebyvertical permanent means of access at each end of the tank. Wheretheverticaldistanceislessthan6m,alternativemeans as defined in 3.9 or portable means of access may be utilised in lieu of the permanent means of access. To facilitate the operationofthealternativemeansofaccess,in-lineopenings in horizontal stringers shallbe provided. The openings shall beofanadequatediameterandshallhavesuitableprotective railings. Thelongitudinalcontinuouspermanentmeansofaccessmay be installed at a minimum 1,6 m to maximum 3 m from the top of the bilge hopper section. In this case, a platform extending the longitudinal continuous permanent means of access in way of the webframe may be used to access the identified structural critical areas. Alternatively,thecontinuouslongitudinalpermanentmeans of access may be installed at a minimum of 1,2 m below the top of the clear opening of the web ring allowing a use of portablemeansofaccesstoreachidentifiedstructuralcritical areas. Fore peak tanks For fore peak tanks with a depth of 6 m or more at the centre lineofthecollisionbulkhead,asuitablemeansofaccessshall beprovidedforaccesstocriticalareassuchastheunderdeck structure,stringers,collisionbulkheadandsideshellstructure Stringers of less than 6 m in vertical distance from the deck headorastringerimmediatelyaboveareconsideredtoprovide suitableaccessincombinationwithportablemeansofaccess. In case the vertical distance between the deck head and stringers,stringersortheloweststringerandthetankbottom is 6 m or more, alternative means of access as defined in 3.9 shall be provided. BKI - Rules for Hull - 2014
- 336. N Section 21 - Hull Outfit21-18/21 Table 21.7 Means of access for bulk carriers Cargo holds Ballast tanks Access to underdeck structure Permanent means of access shall be fitted to provide access to the overhead structure at both sides of the cross deck and in the vicinity of the centreline. Each means of access shall be accessible from the cargo hold access or directly from the main deck and installed at a minimum of 1,6 m to a maximum of 3 m below the deck. An athwartship permanent means of access fitted on the transverse bulkhead at a minimum 1,6 m to a maximum 3 m below the cross-deck head is accepted as equivalent. Accesstothepermanentmeansofaccesstooverheadstructure of the cross deck may also be via the upper stool. Shipshaving transverse bulkheads withfullupperstoolswith access from the main deck which allows monitoring of all framingandplatesfrominsidedonotrequirepermanentmeans of access of the cross deck. Alternatively, movable means of access may be utilized for accesstotheoverheadstructureofthecrossdeckifitsvertical distance is 17 m or less above the tank top. Top side tanks For eachtopside tank of which the height is 6 m and over, one longitudinal continuous permanent means of access shall be providedalongthesideshellwebsandinstalledataminimum of1,6mtoamaximumof3mbelowdeckwithaverticalaccess ladder in the vicinity of each access to that tank. If no access holes are provided through the transverse webs within 600 mm of the tank base and the web frame rings have a web height greater than 1 m inway of side shell and sloping plating, then step rungs/grab rails shall be provided to allow safe access over each transverse web frame ring. Three permanent means of access, fitted at the end bay and middlebayofeachtank,shallbeprovidedspanningfromtank base up to the intersection of the sloping plate with the hatch sidegirder.The existinglongitudinalstructure,iffittedonthe sloping plate in the space may be used as part of this means of access. For topside tanks of which the height is less than 6 m, alternative means as defined in 3.9 or portable means may be utilized in lieu of the permanent means of access Access to vertical structures Permanent means of vertical access shall be provided in all cargo holds and built into the structure to allow for an inspection of a minimum of 25 % of the total number of hold framesportandstarboardequallydistributedthroughoutthe hold including at each end in way of transverse bulkheads. But in no circumstance shall this arrangement be less than 3 permanent means of vertical access fitted to each side (fore and aft ends of hold and mid-span). Permanent means of vertical access fitted between two adjacent hold frames is counted for an access for the inspection of both hold frames. A means of portable access may be used to gain access over the sloping plating of lower hopper ballast tanks. In addition, portable or movable means of access shall be utilized for access to the remaining hold frames up to their upper brackets and transverse bulkheads. Bilge hopper tanks Foreachbilgehoppertankofwhichtheheightis6mandover, onelongitudinalcontinuouspermanentmeansofaccessshall be provided along the side shell webs and installed at a minimum of 1,2 m below the top of the clear opening of the web ring with a vertical access ladder in the vicinity of each access to the tank. An access ladder between the longitudinal continuous permanent means of access and the bottom of the space shall be provided at each end of the tank. Alternatively, the longitudinal continuous permanent means ofaccess canbelocatedthroughtheupperwebplatingabove theclearopeningofthewebring,ataminimumof1,6mbelow thedeckhead,whenthisarrangementfacilitatesmoresuitable inspectionofidentifiedstructurallycriticalareas.Anenlarged longitudinalframecanbeusedforthepurposeofthewalkway. BKI - Rules for Hull - 2014
- 337. Section 21 - Hull Outfit N 21-19/21 Table 21.7 Means of access for bulk carriers (continued) Cargo holds Ballast tanks The width of vertical ladders for access to hold frames shall be at least 300 mm, measured between stringers. A single vertical ladder over 6 m in length is acceptable for the inspection of the hold side frames in a single skin construction. For double-side skin construction no vertical ladders for the inspectionofthecargoholdsurfacesarerequired.Inspection of this structure should be provided from within the double hull space. Fordouble-sideskinbulkcarriers,thelongitudinalcontinuous permanent means of access may be installed within 6 m from the knuckle point of the bilge, if used in combination with alternative methods to gain access to the knuckle point. If no access holes are provided through the transverse ring webs within 600 mm of the tank base and the web frame rings have a web height greater than 1 m in way of side shell and sloping plating, then step rungs/grab rails shall be provided to allow safe access over each transverse web frame ring. For bilge hopper tanks of which the height is less than 6 m, alternative means as defined in 3.9 or portable means may beutilizedinlieuofthepermanentmeansofaccess.Suchmeans ofaccessshallbedemonstratedthattheycanbedeployedand made readily available in the areas where needed. Double-skin side tanks Permanent means of access shall be provided in accordance with the applicable sections of Tables 21.6. Fore peak tanks For fore peak tanks with a depth of 6 m or more at the centrelineofthecollisionbulkhead,asuitablemeansofaccess shall be provided for access to critical areas such as the underdeck structure, stringers, collision bulkhead and side shell structure. Stringers of less than 6 m in vertical distance from the deck headorastringerimmediatelyaboveareconsideredtoprovide suitableaccessincombinationwithportablemeansofaccess. In case the vertical distance between the deck head and stringers, stringers or the loweststringerandthetankbottom is 6 m or more, alternative means of access as defined in 3.9 shall be provided. 3.6 Thewidthofinclinedladders between stringers shall not be less than 400mm. Thetreads shallbeequally spaced at a distance apart, measured vertically, of between 200 mm and 300 mm. When steel is used, the treads shall be formed of two square bars of not less than 22 mm by 22 mm in section, fitted to form a horizontal step with the edges pointing upward. The treads shall be carried through the sidestringersandattachedtheretobydoublecontinuouswelding.Allinclinedladders shall be provided with handrails of substantial construction on both sides, fitted at a convenient distance above the treads. 3.7 For vertical ladders or spiral ladders, the width and construction should be in accordance with international or national standards accepted by the Administration. 3.8 No free-standing portable ladder shall be more than 5 m long. 3.9 Alternative means of access include, but are not limited to, such devices as : – hydraulic arm fitted with a stable base – wire lift platform – staging – rafting – root arm or remotely operated vehicle (ROV) – portable ladders more than 5 m long shall only be utilized if fitted with a mechanical device to secure the upper end of the ladder BKI - Rules for Hull - 2014
- 338. N Section 21 - Hull Outfit21-20/21 – other means of access, approved by and acceptable to the Administration Means for safe operation and rigging of such equipment to and from and within the spaces shall be clearly described in the Ship Structure Access Manual. 3.10 For access through horizontal openings, hatches or manholes, the minimum clear opening shall not be less than 600 mm X 600 mm. When access to a cargo hold is arranged through the cargo hatch, the top of the ladder shall be placed as close as possible to the hatch coaming. Access hatch coamings having a height greater than 900 mm shall also have steps on the outside in conjunction with the ladder. 3.11 For access through vertical openings, or manholes, in swash bulkheads, floors, girders and web frames providing passage through the length and breadth of the space, the minimum opening shall be not less than 600 mm x 800 mm at a height of not more than 600 mm from the passage unless gratings or other foot holds are provided. 3.12 For oil tankers of less than 5,000 tonnes deadweight, the Administration may approve, in special circumstances, smaller dimensions for the openings referred to in 3.10 and 3.11, if the ability to traverse such openings or to remove an injured person can be proved to the satisfaction of the Administration. 3.13 For bulk carriers, access ladders to cargo holds and other spaces shall be: 3.13.1 Where the vertical distance between the upper surface of adjacent decks or between deck and the bottom of the cargo space is not more than 6 m, either a vertical ladder or an inclined ladder. 3.13.2 Where the vertical distance between the upper surface of adjacent decks or between deck and the bottom of the cargospaceismorethan6m,aninclinedladderorseriesofinclinedladdersatoneendofthecargohold,excepttheuppermost 2,5 m of a cargo space measured clear of overhead obstructions and the lowest 6 m may have vertical ladders, provided that the vertical extent of the inclined ladder or ladders connecting the vertical ladders is not less than 2,5 m. The second means of access at the other end of the cargo hold may be formed of a series of staggered vertical ladders, which should comprise of one or more ladder linking platforms spaced not more than 6 m apart vertically and displaced to one side of the ladder. Adjacent sections of ladder should be laterally offset from each other by at least the width of the ladder. Theuppermostentrancesectionoftheladderdirectlyexposedtoacargoholdshouldbeverticalforadistanceof2,5mmeasured clear of overhead obstructions and connected to a ladder-linking platform. 3.13.3 A vertical ladder may be used as a means of access to topside tanks, where the vertical distance is 6 m or less between the deck and the longitudinal means of access in the tank or the stringer or the bottom of the space immediately belowtheentrance.Theuppermostentrancesectionfromdeckoftheverticalladderofthetankshouldbeverticalforadistance of 2,5 m measured clear of overhead obstructions and comprise a ladder linking platform, unless landing on the longitudinal means of access, the stringer or the bottom within the vertical distance, displaced to one side of a vertical ladder. 3.13.4 Unless allowed in 3.13.3 above, an inclined ladder or combination of ladders should be used for access to a tank or a space where the vertical distance is greater than 6 m between the deck and a stringer immediately below the entrance, between stringers, or between the deck or a stringer and the bottom of the space immediately below the entrance. 3.13.5 In case of 3.13.4 above, the uppermost entrance section from deck of the ladder should be vertical for a distance of 2,5 m clear of overhead obstructions and connected to a landing platform and continued with an inclined ladder. The flights of inclined ladders should not be more than 9 m in actual length and the vertical height should not normally be more than 6 m. The lowermost section of the ladders may be vertical for a distance of not less than 2,5 m. 3.13.6 In double-side skin spaces of less than 2,5 m width, the access to the space may be by means of vertical ladders that comprise of one or more ladderlinking platforms spaced not more than 6 m apart vertically and displaced to one side of the ladder. Adjacent sections of ladder should be laterally offset from each other by at least the width of the ladder. 3.13.7 A spiral ladder is considered acceptable as an alternative for inclined ladders. In this regard, the uppermost 2,5 m can continue to be comprised of the spiral ladder and need not change over to vertical ladders. 3.14 The uppermost entrance section from deck of the vertical ladder providing access to a tank should be vertical for a distance of 2,5 m measured clear of overhead obstructions and comprise a ladder linking platform, displaced to one side of a vertical ladder. The vertical ladder can be between 1,6 m and 3 m below deck structure if it lands on a longitudinal or athwartship permanent means of access fitted within that range. BKI - Rules for Hull - 2014
- 339. Section 21 - Hull Outfit N, O, P 21-21/21 4. Ship structure access manual 4.1 Aship'smeansofaccesstocarryoutoverallandclose-upinspectionsandthicknessmeasurementsshallbe described in a Ship structure access manual approved by the Administration, an updated copy of which shall be kept on board. The Ship structure access manual shall include the following for each space in the cargo area: – plans showing the means of access to the space, with appropriate technical specifications and dimensions. – plans showing the means of access withineachspace to enable an overall inspection to be carried out, with appropriate technical specifications and dimensions. The plans shall indicate from where each area in the space can be inspected. – plans showing the means of access within the space to enable close-up inspections to be carried out, with appropriate technical specifications and dimensions. The plans shall indicate the positions of critical structural areas, whether the means of access is permanent or portable and from where each area can be inspected. – instructions for inspecting and maintaining the structural strength of all means of access and means of attachment, taking into account any corrosive atmosphere that may be within the space – instructions for safety guidance when rafting is used for close-up inspections and thickness measurements – instructions for the rigging and use of any portable means of access in a safe manner – an inventory of all portable means of access – records of periodical inspections and maintenance of the ship's means of access 4.2 For the purpose of these regulations "critical structural areas" are locations which have been identified from calculations to require monitoring or from the service history of similar or sister ships to be sensitive to cracking, buckling, deformation or corrosion which would impair the structural integrity of the ship. 5. Other Regulations and Recommendations Attention is drawn to Chapter 6 of the "Guidelines for the Inspection and Maintenance of Double Hull Tanker Structures", Tanker Structure Co-operative Forum 1995. O. Guard - Rails 1. Efficient guard-rails or bulwarks are to be fitted on all exposed parts of the freeboard and superstructure decks. The height is to be at least 1,0 m from the deck. 2. The height below the lowest course of the guard-rails is not to exceed 230 mm. The other courses are not to be spaced more than 380 mm apart. 3. In the case of ships with rounded gunwales the guard-rail supports are to be placed on the flat part of the deck. 4. Guard-rails are to be constructed in accordance with DIN 81702 standards. Equivalent constructions of sufficient strength and safety can be accepted. 5. Guard-rail stanchions are not to be welded to the shell plating. P. Access to Ships The design appraisal and testing of accesses to ships (accomodation ladders, gangways) are not part of Classification However, approval of substructures in way of accomodation ladders and gangways is part of Classification. BKI - Rules for Hull - 2014
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- 341. Section 22 - Structural Fire Protection on Board Seagoing Ships A 22-1/48 Section 22 Structural Fire Protection on Board Seagoing Ships A. General 1. Application, submission of plans 1.1 These regulations apply to ships to be classed for unrestricted service. Forshipsclassedforrestrictedserviceorshipswhichareintendedtotradewithinspecifiedlimitsaswellasforfishingvessels, pontoons without propulsion, barges and dredgers exceptions from the requirements of this Section may be permitted. 1.2 The terms used in this Section correspond to the definitions as per Chapter II-2, Regulation 3 of SOLAS 74. 1.3 The term "Approved" relates to a material or construction, for which BKI has issued an Approval Certificate. A type approval can be issued on the basis of a successful standard fire test, which has been carried out by a neutral and recognized fire testing institute. 1.4 The fire safety design and arrangements may differ from the prescriptive regulations of this section, provided that the design and arrangements meet the fire safety objectives and functional requirements of Chapter II-2 of SOLAS 741) . Compliance of the alternative design and arrangements needs to be verified by an engineering analysis which consist of three steps – Qualitative Design Review (QDR) – Modelling/ Data Analysis (MDA) – Quantitative Risk Analysis (QRA). 1.5 Documents to be submitted The following drawings and documents are to be submitted, at least in triplicate2) for approval. BKI reserves its right to ask for supplementary copies, if deemed necessary. – Fire division plan – Insulation plan – Joiner plan – Ventilation and Air condition scheme – Deck covering plan – Door plan – Window plan – Fire control plan – List of approved materials and equipment Additional drawings for passenger ships – Escape way plan incl. escape way calculation – Evacuation analysis (only Ro-Ro passenger ships) – Fire load calculation – Safety sign scheme 1.6 Type"A","B"and"C"classpartitions, fire dampers, ductpenetrations as wellas the insulationmaterials,linings, 1) Reference is made to the "Guidelines on Alternative Design and Arrangements for Fire Safety" adopted by IMO by MSC/Circ.1002 2) For Indonesian flagship in quadruplicate (one for Indonesian government). BKI - Rules for Hull - 2014
- 342. A,B Section 22 - Structural Fire Protection on Board Seagoing Ships22-2/48 ceilings, surface materials and not readily ignitable deck coverings shall be of approved type. 1.7 Forregulationsonfirealarmsystemsandonfireextinguishingarrangements,seeRulesforMachineryInstallations, Volume III, Section 12. 1.8 IACS Unified Interpretations have to be observed and shall be complied with. B. Regulations on Fire Protection for Passenger Ships carrying more than 36 Passengers 1. Materials 1.1 Thehull,decks,structuralbulkheads,superstructuresanddeckhousesaretobeofsteelorotherequivalentmaterials (Aluminium alloy suitably insulated). 1.2 Components made from aluminium alloys require special treatment, with regard to the mechanical properties of the material in case of temperature increase. In principle, the following is to be observed: 1.2.1 The insulation of "A" or "B" class divisions shall be such that the temperature of the structural core does not rise more than 200EC above the ambient temperature at any time during the applicable fire exposure to the standard fire test. 1.2.2 Special attention shall be given to the insulation of aluminium alloy components of columns, stanchions and other structural members required to support lifeboat and liferaft stowage, launching and embarkation areas, and "A" and "B" class divisions to ensure: that for such members supporting lifeboat and liferaft areas and "A"class divisions, the temperature rise limitation specified in1.2.1shallapplyattheendofonehour;andthatfor suchmembers required to support "B"class divisions, the temperature rise limitation specified in 1.2.1 shall apply at the end of half an hour. 1.2.3 Crowns and casings of machinery spaces of category A shall be of steel construction and be insulated as required by Table 22.1 as appropriate. Openings therein, if any, shall be suitably arranged and protected to prevent the spread of fire. 2. Main vertical zones and horizontal zones 2.1 The hull, superstructures and deckhouses are to be subdivided into main vertical zones the average length and width of which on any deck is generally not to exceed 40 m. Subdivision is to be effected by "A-60" class divisions. Steps and recesses shall be kept to a minimum. Where a category 4.3 [5], 4.3 [9] or 4.3 [10] space is on one side of the division or where fuel oil tanks are on both sides of the division the standard may be reduced to "A-0". As far as practicable, the bulkheads forming the boundaries of the main vertical zones above the bulkhead deck shall be in line with watertight subdivision bulkheads situated immediately below the bulkhead deck. The length and width of main vertical zones may be extended to a maximum of 48 m in order to bring the ends of main vertical zones to coincide with subdivision watertight bulkheads or in order to accommodatea large public space extending for the whole length of the main vertical zone provided that the total area of the main vertical zone is not greater than 1600 m2 on any deck. The length or width of a main vertical zone is the maximum distance between the furthermost points of the bulkheads bounding it. The divisions are to be extended from deck to deck and to the shell or other boundaries. At the edges insulating bridges are to be provided where required. 2.2 On ships designed for specialpurposes(automobileor railroad car ferries), where the provision of main vertical zone bulkheads would defeat the purpose for which the ship is intended, equivalent means for controlling and limiting a fire aretobeprovidedandspecificallyapproved.Servicespacesandshipstoresshallnotbelocatedonro-rodecksunlessprotected in accordance with the applicable regulations. 3. Bulkheads within main vertical zones 3.1 All bulkheads which are not required to be "A" class divisions shall be at least "B" class or "C" class divisions as prescribed in Table 22.1. All such divisions may be faced with combustible materials. 3.2 All bulkheads required to be "B"class divisionsshall extend from deck to deck and to the shell or other boundaries BKI - Rules for Hull - 2014
- 343. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-3/48 unless the continuous "B" class ceilings or linings fitted on both sides of the bulkheads are at least of the same fire resistance as the bulkhead, in which case the bulkheads may terminate at the continuous ceiling or lining. 4. Fire integrity of bulkheads and decks 4.1 Inadditiontocomplyingwiththe specific provisionsforfireintegrityofbulkheadsanddecksmentionedelsewhere in this Section, the minimum fire integrity of all bulkheads and decks shall be as prescribed in Tables 22.1 to 22.2. 4.2 The following requirements shall govern application of the tables: Table 22.1 shall apply to bulkheads and walls not bounding either main vertical zones or horizontal zones. Table 22.2 shall apply to decks not forming steps in main vertical zones nor bounding horizontal zones. 4.3 Forthepurposeofdeterminingtheappropriatefireintegritystandardstobeappliedtoboundariesbetweenadjacent spaces, such spaces are classified according to their fire riskasshowninthefollowingcategories1to14. Wherethecontents and use of a space are such that there is a doubt as to its classificationforthepurposeofthisregulation,or whereitispossible to assign two or more classifications to a space, it shall be treated as a space within the relevant category having the most stringent boundary requirements. Smaller, enclosed rooms within a space that have less than 30%communicating openings to that space are to be considered separate spaces. The fire integrity of the boundary bulkheads of such smaller rooms shall beasprescribedinTables22.1and22.2.Thetitleofeachcategoryisintendedtobetypicalratherthanrestrictive.Thenumber in parentheses preceding each category refers to the applicable column or row number in the tables. BKI - Rules for Hull - 2014
- 344. B Section 22 - Structural Fire Protection on Board Seagoing Ships22-4/48 Table 22.1 Bulkheads not bounding either main vertical zones or horizontal zones Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] Control stations [1] B-01 A-0 A-0 A-0 A-0 A-60 A-60 A-60 A-0 A-0 A-60 A-60 A-60 A-60 Stairways [2] A-01 A-0 A-0 A-0 A-0 A-15 A-15 A-03 A-0 A-15 A-30 A-15 A-30 Corridors [3] B-15 A-60 A-0 B-15 B-15 B-15 B-15 A-0 A-15 A-30 A-0 A-30 Evacuation stations and ex- ternal escape routes [4] A-0 A- 602,4 A- 602,4 A- 602,4 A-04 A-0 A-602 A-602 A-602 A-602 Open deck spaces [5] S A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 Accommodation spaces of minor fire risk [6] B-0 B-0 B-0 C A-0 A-0 A-30 A-0 A-30 Accommodation spaces of moderate fire risk [7] B-0 B-0 C A-0 A-15 A-60 A-15 A-60 Accommodation spaces of greater fire risk [8] B-0 C A-0 A-30 A-60 A-15 A-60 Sanitary and similar spaces [9] C A-0 A-0 A-0 A-0 A-0 Tanks, voids and auxiliary machinery spaces having little or no fire risk [10] A-01 A-0 A-0 A-0 A-0 Auxiliary machinery spaces, cargo spaces, cargo and other oil tanks and other similar spaces of moderate fire risk [11] A-01 A-0 A-0 A-15 Machinery spaces and main galleys [12] A-01 A-0 A-60 Store-rooms, workshops, pantries etc. [13] A-01 A-0 Other spaces in which flammable, liquids are stowed [14] A-30 Notes to be applied to Tables 22.1 to 22.2, as appropriate. 1. Whereadjacentspacesareinthesamenumericalcategoryandsuperscript1appears,abulkheadordeckbetweensuchspaces need not be fitted. For example, in category [12] a bulkhead need not be required between a galley and its annexed pantries provided the pantry bulkheads and decks maintain the integrity of the galley boundaries. A bulkhead is, however, required between a galley and a machinery space even though both spaces are in category [12]. 2. The ship's side, to the waterline in the lightest seagoing condition, superstructure and deckhouse sides situated below and adjacent to the liferafts and evacuation slides may be reduced to "A-30" 3. Wherepublictoiletsareinstalledcompletelywithinthestairwayenclosure,thepublictoiletbulkheadwithinthestairwayenclosure can be of "B" class integrity. 4. Where spaces of category [6], [7], [8] and [9] are located completely within the outer perimeter of the muster station, the bulkheads of these spaces are allowed to be of "B-0" class integrity. Control positions for audio, video and light installations may be considered as part of the muster station. BKI - Rules for Hull - 2014
- 345. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-5/48 Table 22.2 Decks not forming steps in main vertical zones nor bounding zones Spaces above [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] Spaces below Control stations [1] A-30 A-30 A-15 A-0 A-0 A-0 A-15 A-30 A-0 A-0 A-0 A-60 A-0 A-60 Stairways [2] A-0 A-0 n A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-30 A-0 A-30 Corridors [3] A-15 A-0 A-01 A-60 A-0 A-0 A-15 A-15 A-0 A-0 A-0 A-30 A-0 A-30 Evacuation stations and ex- ternal escape routes [4] A-0 A-0 A-0 A-0 n A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 Open deck spaces [5] A-0 A-0 A-0 A-0 n A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 Accommodation spaces of minor fire risk [6] A-60 A-15 A-0 A-60 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 Accommodation spaces of moderate fire risk [7] A-60 A-15 A-15 A-60 A-0 A-0 A-15 A-15 A-0 A-0 A-0 A-0 A-0 A-0 Accommodation spaces of greater fire risk [8] A-60 A-15 A-15 A-60 A-0 A-15 A-15 A-30 A-0 A-0 A-0 A-0 A-0 A-0 Sanitary and similar spaces [9] A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 Tanks, voids and auxiliary machinery spaces having little or no fire risk [10] A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-0 A-01 A-0 A-0 A-0 A-0 Auxiliary machinery spaces, cargo spaces, cargo and other oil tanks and other similar spaces of moderate fire risk [11] A-60 A-60 A-60 A-60 A-0 A-0 A-15 A-30 A-0 A-0 A-01 A-0 A-0 A-30 Machinery spaces and main galleys [12] A-60 A-60 A-60 A-60 A-0 A-60 A-60 A-60 A-0 A-0 A-30 A-301 A-0 A-60 Store-rooms, workshops, pantries etc. [13] A-60 A-30 A-15 A-60 A-0 A-15 A-30 A-30 A-0 A-0 A-0 A-0 A-0 A-0 Other spaces in which flammable, liquids are stowed [14] A-60 A-60 A-60 A-60 A-0 A-30 A-60 A-60 A-0 A-0 A-0 A-0 A-0 A-0 See notes under Table 22.1 [1] Control stations Spaces containing emergency sources of power and lighting. Wheelhouse and chartroom. Spaces containing the ship's radio equipment. Fire control stations. Control room for propulsion machinery when located outside the propulsion machinery space.Spacescontainingcentralizedfirealarmequipment.Spacescontaining centralized emergency public address system stations and equipment. [2] Stairways Interior stairways, lifts, totally enclosed emergency escape trunks and escalators (other than those wholly contained within the machinery spaces) for passengers and crew and enclosures thereto. In this connection, a stairway which is enclosed at only one level shall be regarded as part of the space from which it is not separated by a fire door. BKI - Rules for Hull - 2014
- 346. B Section 22 - Structural Fire Protection on Board Seagoing Ships22-6/48 [3] Corridors Passenger and crew corridors and lobbies. [4] Evacuation stations and external escape routes. Survival craft stowage area. Open deck spaces and enclosed promenades forming lifeboat and liferaft embarkation and lowering stations. Assembly stations, internal and external. External stairs and open decks used for escape routes. The ship's side to the waterline in the lightest seagoing condition, superstructure and deck house sides situated below and adjacent to the liferaft's and evacuation slide's embarkation areas. [5] Open deck spaces Open deck spaces and enclosed promenades clear of lifeboat and liferaft embarkation and lowering stations. To be considered in this category, enclosed promenades shall have no significant fire risk, meaning that furnishings shall be restricted to deck furniture. In addition, such spacesshall be naturally ventilated by permanent openings. Air spaces (the space outside superstructures and deckhouses). [6] Accommodation spaces of minor fire risk Cabins containing furniture and furnishings of restricted fire risk. Offices and dispensaries containing furniture and furnishings of restricted fire risk. Public spaces containing furniture and furnishings of restricted fire risk and having a deck area of less than 50 m2 . [7] Accommodation spaces of moderate fire risk Spacesasincategory [6] above butcontaining furnitureandfurnishings of other than restricted fire risk. Public spaces containing furniture and furnishings of restricted fire risk and having a deck area of 50 m2 or more. Isolated lockers andsmallstore-roomsinaccommodationspaceshavingareaslessthan4m2 (inwhichflammableliquidsarenotstowed). Sale shops. Motion picture projection and film stowage rooms. Diet kitchens (containing no open flame). Cleaning gear lockers (in which flammable liquids are not stowed). Laboratories (in which flammable liquids are not stowed). Pharmacies.Smalldryingrooms(havingadeckareaof4m2 orless).Specierooms,operatingrooms, electricaldistribution boards (see 4.3.2 and 4.3.3). [8] Accommodation spaces of greater fire risk Public spaces containing furniture and furnishings of other than restricted fire risk and having a deck area of 50 m2 or more. Barber shops and beauty parlours. Saunas. [9] Sanitary and similar spaces Communal sanitary facilities, showers, baths, water closets, etc. Small laundry rooms. Indoor swimming pool area. Isolated pantries containing no cooking appliances in accommodation spaces. Private sanitary facilities shall be considered a portion of the space in which they are located. [10] Tanks, voids and auxiliary machinery spaces having little or no fire risk. Watertanksformingpartoftheship'sstructure.Voidsandcofferdams.Auxiliarymachineryspaceswhichdonotcontain machinery having a pressure lubrication system and where storage of combustibles is prohibited, such as: Ventilationandair-conditioningrooms;windlassroom;steeringgearroom;stabilizerequipmentroom;electricalpropulsion motor room; rooms containing section switchboards and purely electrical equipment other than oil-filled electrical transformers(above10kVA);shaftalleysandpipetunnels;spacesforpumpsandrefrigerationmachinery(nothandling or using flammable liquids). Closed trunks serving the spaces listed above. Other closed trunks such as pipe and cable trunks. [11] Auxiliary machinery spaces, cargo spaces, cargo and other oil tanks and other similar spaces of moderate fire risk Cargo oil tanks. Cargo holds, trunkways and hatchways. Refrigerated chambers. Oil fuel tanks (where installed in a separatespacewithnomachinery).Shaftalleysandpipetunnelsallowingstorageofcombustibles. Auxiliary machinery spacesasincategory[10] whichcontainmachineryhavingapressurelubricationsystemorwherestorageofcombustibles ispermitted.Oilfuelfillingstations.Spacescontainingoil-filledelectricaltransformers (above10kVA).Spacescontaining BKI - Rules for Hull - 2014
- 347. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-7/48 turbine and reciprocating steam engine driven auxiliary generators and small internal combustion engines of power output up to 110 kW driving generators, sprinkler, drencher or fire pumps, bilge pumps, etc. Closed trunks serving the spaces listed above. [12] Machinery spaces and main galleys Mainpropulsionmachineryrooms (otherthanelectricpropulsionmotorrooms)andboilerrooms.Auxiliarymachinery spaces other than those in categories [10] and [11] whichcontain internal combustion machinery or other oil-burning, heating or pumping units. Main galleys and annexes. Trunks and casings to the spaces listed above. [13] Store-rooms, workshops, pantries, etc. Main pantries not annexed to galleys. Main laundry. Large drying rooms (having a deck area of more than 4 m2 ). Miscellaneous stores. Mail and baggage rooms. Garbage rooms. Workshops (not part of machinery spaces. galleys, etc.), lockers and store-rooms having areas greater than 4 m2 , other than those spaces which have provisions for the storage of flammable liquids. [14] Other spaces in which flammable liquids are stowed Lamp rooms. Paint rooms. Store-rooms containing flammable liquids (including dyes, medicines, etc.). Laboratories (in which flammable liquids are stowed). 4.3.1 In respect of category [5] spaces BKI shall determine whether the insulation values in Table 22.1 shall apply to ends of deckhouses and superstructures, and whether the insulation values in Table 22.2 shall apply to weather decks. Innocase shallthe requirements ofcategory [5] ofTables 22.1and22.2necessitate enclosure ofspaces whichinthe opinion of BKI need not be enclosed. 4.3.2 Electricaldistributionboardsmaybelocatedbehindpanels/liningswithinaccommodationspacesincluding stairway enclosures, without the need to categorize the space, provided no provision for storage is made. 4.3.3 If distribution boards are located in an identifiable space having a deck area of less than 4 m², this space shall be categorized in [7]. 4.4 Continuous "B" class ceilings or linings, in association with the relevant decks or bulkheads, may be accepted as contributing wholly or in part, to the required insulation and integrity of a division. 4.5 At intersections and terminal points of the required fire insulation constructions due regard is to be paid to the effect of thermal bridges. In order to avoid this, the insulation of a deck or bulkhead shall be carried past the intersection or terminal point for a distance of at least 450 mm. 5. Protection of stairways and lifts in accommodation and service spaces 5.1 Allstairwaysinaccommodationandservicespacesaretobeofsteelframeorotherapprovedequivalentconstruction; they are to be arranged within enclosures formed by "A" Class division, with effective means of closure for all openings. The following exceptions are admissible: 5.1.1 Astairwayconnectingonlytwodecksneednotbeenclosed,providedthattheintegrityofthepierceddeckismaintained by suitable bulkheads or doors at one of the two decks. When a stairway is closed at one ‘ween deck space, the stairway enclosure shall be protected in accordance with the tables for decks. 5.1.2 Stairways fitted within a closed public space need not be enclosed. 5.2 Stairway enclosures are to be directly accessible from the corridors and of sufficient area to prevent congestion, having in mind the number of persons likely to use them in an emergency. Within the perimeter of such stairway enclosures, onlypublictoilets,lockersofnon-combustiblematerialprovidingstorageforsafetyequipmentandopeninformationcounters are permitted. Only public spaces, corridors, public toilets, special category spaces, other escape stairways required by 12.3.3 and external areas are permitted to have direct access to these stairway enclosures. Small corridors or lobbies used to separate an enclosed stairway from galleys or main laundries may have direct access to the stairway provided they have a minimum deck area of 4,5 m², a width of no less than 900 mm and contain a fire hose station. 5.3 Lift trunks shall be so fitted as to prevent the passage of smoke and flame from one 'tweendeck to another and BKI - Rules for Hull - 2014
- 348. B Section 22 - Structural Fire Protection on Board Seagoing Ships22-8/48 shall be provided with means of closing so as to permit the control of draught and smoke. 6. Openings in "A" class divisions 6.1 Where"A"classdivisionsarepenetratedfor the passage ofelectric cables, pipes,trunks,ducts,etc.,orforgirders, beams or other structural members, arrangements shall be made to ensure that the fire resistance is not impaired, subject to the provisions of 6.6. 6.2 All openings in the divisions are to be provided with permanently attached means of closing which shall be at least as effective for resisting fire as the divisions. This does not apply for hatches between cargo, special category, store and baggage spaces and between such spaces and the weather decks. 6.3 The construction ofalldoors anddoorframesin"A"class divisions, with the means ofsecuring them when closed, shall provide resistance to fire as well as to the passage of smoke and flame equivalent to that of the bulkheads in which the doors are situated 3) . Such doors and door frames shall be approved by BKI and constructed of steel or other equivalent material. Watertight doors need not be insulated. 6.4 It shall be possible for each door to be opened and closed from each side of the bulkhead by one person only. 6.5 Fire doors in main vertical zone bulkheads,galleyboundariesandstairwayenclosuresother thanpower operated watertight doors and those which are normally locked shall satisfy the following requirements: 6.5.1 The doors shall be self-closing and be capable of closing against an angle of inclination of up to 3,5° opposing closure. 6.5.2 The approximate time of closure for hinged fire doors shall be no more than 40 s and no less than 10 s from the beginning of their movement with the ship in upright position. The approximate uniform rate of closure for sliding fire doors shall be of no more than 0,2 m/s and no less than 0,1 m/s with the ship in the upright position. 6.5.3 The doors, except those for emergency escape trunks shall be capable of remote release from the continuously manned central control station, either simultaneously or in groups and shall be capable of release also individually from apositionatbothsidesofthedoor. Release switches shallhave an on-offfunctiontopreventautomaticresettingofthesystem. 6.5.4 Hold-back hooks not subject to central control station release are prohibited. 6.5.5 A door closed remotely from the central control station shall be capable of being re-opened at both sides of the doorbylocalcontrol.Aftersuchlocalopening,thedoorshallautomaticallycloseagain(seealsoRulesforElectricalInstallations, Volume IV, Section 9). 6.5.6 Indication shall be provided at the fire door indicator panel in the continuously manned central control station whether each of the remote-released doors are closed. 6.5.7 The release mechanism shall be so designed that the door will automatically close in the event of disruption of the control system or main source of electric power. 6.5.8 Local power accumulators for power operated doors shall be provided in the immediate vicinity of the doors to enable the doors to be operated after disruption of the control system or main source of electric power at least ten times (fully opened and closed) using the local controls (see also Rules for Machinery Installations, Volume III, Section 14). 6.5.9 Disruption of the control system or main source of electric power at one door shall not impair the safe functioning of the other doors. 6.5.10 Remote-released sliding or power-operated doors shall be equipped with an alarm that sounds for at least 5 s but no more than 10 s after the door is released from the central control station and before the door begins to move and continue sounding until the door is completely closed. 6.5.11 A door designed to re-open upon contacting an object in its path shall re-open not more than 1 m from the point of contact. 3) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 349. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-9/48 6.5.12 Double-leaf doors equipped with a latch necessary to their fire integrity shall have a latch that is automatically activated by the operation of the doors when released by the control system. 6.5.13 Doors giving direct access to special category spaces which are power-operated and automatically closed need not be equipped with the alarms and remote release mechanisms required in 6.5.3 and 6.5.10. 6.5.14 The components of the local control system shall be accessible for maintenance and adjusting. 6.5.15 Power-operated doors shall be provided with a control system of an approved type which shall be able to operate in case of fire4) . This system shall satisfy the following requirements: 6.5.15.1 The control system shall be able to operate the door at the temperature of at least 200 °C for at least 60 min, served by the power supply; 6.5.15.2 The power supply for all other doors not subject to fire shall nor be impaired; and 6.5.15.3 At temperatures exceeding 200 °C the control system shall be automatically isolated from the power supply and shall be capable of keeping the door closed up to at least 945 °C. 6.6 Therequirementsfor"A"classintegrityoftheouterboundariesofashipshallnotapplytoglasspartitions,windows andsidescuttles,providedthatthereisnorequirementforsuchboundariestohave"A"classintegrityin8.3.Therequirements for "A"class integrity of the outer boundaries of the ship shall not apply to exterior doors, except for those in superstructures anddeckhousesfacinglife-savingappliances, embarkationandexternalmuster stationareas, externalstairs andopendecks used for escape routes. Stairway enclosure doors need not meet this requirement. 6.7 Exceptforwatertight,weathertightdoors(semi-watertightdoors),doorsleadingtotheopendeckanddoorswhich need to be reasonably gastight, all "A" class doors located in stairways, public spaces and main vertical zone bulkheads inescaperoutesshallbeequippedwithaself-closinghoseportofmaterial,constructionandfireresistancewhichisequivalent to the door into which it is fitted, and shall be a 150 mm square clear opening with the door closed and shall be inset into the lower edge of the door, opposite the door hinges, or in the case of sliding doors, nearest the opening. 7. Openings in "B" class divisions 7.1 Where "B" class divisions are penetrated for the passage of electric cables, pipes, trunks, ducts, etc., or for the fittingofventilationterminals,lightingfixturesandsimilardevices,arrangementsshallbemadetoensurethatthefireresistance is not impaired. Pipes other than steel or copper that penetrate "B" class divisions shall be protected by either: – a fire tested penetration device, suitable for the fire resistance of the division pierced and the type of pipe used; or – a steel sleeve, having a thickness of not less than 1,8 mm and a length of not less than 900 mm for pipe diameters of 150 mm or more and not less than 600 mm for pipe diameters of less than 150 mm, preferably equally divided to each side of the division. The pipe shall be connected to the ends of the sleeve by flanges or couplings; or the clearance between the sleeve and the pipe shall not exceed 2,5 mm; or any clearance between pipe and sleeve shall be made tight by means of non- combustible or other suitable material. 7.2 Doors and door frames in "B"class divisions and means ofsecuring them shall provide a method of closure which shallhave resistance to fire equivalent to that of the divisions5) except that ventilation openings may be permitted in the lower portion of such doors. Where such opening is in or under a door the total net area of any such opening or openings shall notexceed0,05m2 .Alternatively,anon-combustibleair balance duct routed between the cabin and the corridor, and located belowthesanitaryunitispermittedwherethecross-sectionalareaoftheductdoesnotexceed0,05m².Allventilationopenings shall be fitted with a grill made of non-combustible material. Doors shall be non-combustible and approved by BKI. 7.3 Cabin doors in "B" class divisions shall be of a self-closing type. Hold-backs are not permitted. 7.4 Therequirementsfor"B"classintegrityoftheouterboundariesofashipshallnotapplytoglasspartitions,windows and sidescuttles. Similarly, the requirements for "B" class integrity shall not apply to exterior doors in superstructures and deckhouses. 4) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). 5) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 350. B Section 22 - Structural Fire Protection on Board Seagoing Ships22-10/48 8. Windows and sidescuttles 8.1 All windows and sidescuttles in bulkheads within accommodation and service spaces and control stations other than those to which the provisions of 6.6 and of 7.4 apply, shall be so constructed as to preserve the integrity requirements of the type of bulkheads in which they are fitted. 8.2 Notwithstanding the requirements of the Tables 22.1 to22.2 all windows and sidescuttles in bulkheads separating accommodationandservicespacesandcontrolstationsfromweathershallbeconstructedwithframesofsteelorothersuitable material. The glass shall be retained by a metal glazing bead or angle. 8.3 Windows facing life-saving appliances, embarkation and muster areas, external stairs and open decks used for escape routes, andwindowssituatedbelowliferaftandescapeslideembarkationareasshallhavethefireintegrityasrequired intheTables22.1to22.2.Whereautomaticdedicatedsprinklerheadsareprovidedfor windows (seealso Rules for Machinery Installations, Volume III, Section 12), A-0 windows may be accepted as equivalent. Windows located in the ship's side below the lifeboat embarkation areas shall have the fire integrity at least equal to "A-0" class. 9. Ventilation systems 9.1 In general, the ventilation fans shall be so disposed that the ducts reaching the various spaces remain within the main vertical zone. 9.2 Whereventilationsystemspenetratedecks,precautionsshallbetaken,inadditiontothoserelatingtothefireintegrity of the deck required by 6. to reduce the likelihood of smoke and hot gases passing from one between deck space to another through the system. In addition to insulation requirements contained in 9. vertical ducts shall, if necessary, be insulated as required by the appropriate tables in 4. 9.3 The main inlets and outlets of all ventilation systems shall be capable of being closed from outside the respective spaces in the event of a fire. 9.4 Except in cargo spaces, ventilation ducts shall be constructed of the following materials: 9.4.1 Ducts not less than 0,075 m2 in sectional area and all vertical ducts serving more than a single ‘ween deck space shall be constructed of steel or other equivalent material. 9.4.2 Ducts less than 0,075 m2 in sectional area other than vertical ducts referred to in 9.4.1 shall be constructed of non-combustible materials. Where such ducts penetrate "A" or "B" Class divisions due regard shall be given to ensuring the fire integrity of the division. 9.4.3 Shortlengthsofduct,notingeneralexceeding0,02m2 insectionalareanor2minlength,neednotbenon-combustible provided that all of the following conditions are met: 9.4.3.1 The duct is constructed of a material having low flame spread characteristics6) which is type approved. 9.4.3.2 The duct is used only at the terminal end of the ventilation system; and 9.4.3.3 The duct is not located closer than 0,6 m measured along its length to a penetration of an "A"or "B"class division, including continuous "B" class ceilings. 9.5 Stairway enclosures shall be ventilated by an independent fan and duct system which shall not serve any other spaces in the ventilation system. 9.6 All power ventilation, except machinery and cargo spaces ventilation and any alternative system which may be required under 9.9, shall be fitted with controls so grouped that all fans may be stopped from either of two positions which shall be situated as far apart as practicable. Controls provided for the power ventilation serving machinery spaces shall also be grouped so as to be operable from two positions, one of which shall be outside such spaces. Fans serving power ventilation systems to cargo spaces shall be capable of being stopped from a safe position outside such spaces. 9.7 Where a thin plated duct with a free cross-sectional area equal to or less than 0,02 m² passes through "A" class bulkheads or decks, the opening shall be lined with a steel sheet sleeve having a thickness of at least 3 mm and a length of 6) Reference is made to the Fire Test Procedure Code, Annex 1, Part 5, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 351. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-11/48 at least 200 mm, divided preferably into 100 mm on each side of the bulkhead or, in the case of the deck, wholly laid on the lower side of the decks pierced. Where the ventilation ducts with a free-sectional area exceeding 0,02 m2 pass through "A" class bulkheads or decks, the opening shall be lined with a steel sheet sleeve. However, where such ducts are of steel construction and pass through a deck or bulkhead, the ducts and sleeves shall comply with the following: 9.7.1 Thesleevesshallhaveathicknessofatleast3mmandalengthofatleast900mm.Whenpassingthroughbulkheads, this length shall be divided preferably into 450 mm on each side of the bulkhead. These ducts, or sleeves lining such ducts, shall be provided with fireinsulation.Theinsulationshallhaveatleastthesamefireintegrity as the bulkhead or deck through which the duct passes. 9.7.2 Ducts with a free cross-sectional area exceeding 0,075 m2 shall be fitted with fire dampers in addition to the requirements of 9.7.1. The fire damper shall operate automatically but shall also be capable of being closed manually from both sides of the bulkhead or deck. The damper shall be provided with an indicator which shows whether the damper is open or closed. Fire dampers are not required, however, where ducts pass through spaces surrounded by "A" class divisions, without serving those spaces, provided those ducts have the same fire integrity as the divisions which they pierce. Thefiredampersshouldbeeasilyaccessible.Wheretheyareplacedbehindceilingsandlinings,theselattershouldbeprovided with an inspection door on which a plate reporting the identification number of the fire damper. Such plate and identification number should be placed also on any remote control required. 9.7.3 The following arrangement shall be of an approved type 7) . 9.7.3.1 Fire dampers, including relevant means of operation. 9.7.3.2 Ductpenetrationsthrough"A"classdivisions.Wheresteelsleevesaredirectlyjoinedtoventilationductsbymeans of riveted or screwed flanges or by welding, the test is not required. 9.8 Exhaust ducts from galley ranges in which grease or fat is likely to accumulate shall meet the requirements as mentioned in 9.10.2 and shall be fitted with: 9.8.1 A grease trap readily removable for cleaning unless an alternative approved grease removal system is fitted; 9.8.2 A fire damper located in the lower end of the duct which is automatically and remotely operated, and in addition a remotely operated fire damper located in the upper end of the duct; 9.8.3 A fixed means for extinguishing a fire within the duct (see also Rules for Machinery Installations, Volume.III, Section 12); 9.8.4 Remote control arrangements for shutting off the exhaust fans and supply fans, for operating the fire dampers mentioned in 9.8.2 and for operating the fire-extinguishing system, which shall be placed in a position close to the entrance to the galley. Where a multi branch system is installed, means shall be provided to close all branches exhausting through the same main duct before an extinguishing medium is released into the system; and 9.8.5 Suitably located hatches for inspection and cleaning. 9.9 Such measures as are practicable shall be taken in respect of control stations outside machinery spaces in order to ensure that ventilation, visibility and freedom from smoke are maintained, so that in the event of fire the machinery and equipment contained therein may be supervised and continue to function effectively. Alternative and separate means of air supply shall be provided; air inlets of the two sources of supply shall be so disposed that the risk of both inlets drawing in smoke simultaneously is minimized. Such requirements need not apply to control stations situated on, and opening on to, an open deck. 9.10 TheventilationsystemsformachineryspacesofcategoryA, vehiclespaces,ro-rospaces,galleys,specialcategory spacesandcargospacesshall,ingeneral,beseparatedfromeach other and from the ventilation system serving other spaces. 9.11 Ducts provided for the ventilation of machinery spaces of category A, galleys, vehicle spaces, ro-ro cargo spaces or special category spaces shall not pass through accommodation spaces, service spaces or control stations unless the ducts are either complying with 9.11.1 or 9.11.2. 7) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 352. B Section 22 - Structural Fire Protection on Board Seagoing Ships22-12/48 9.11.1 Constructed of steel having a thickness of at least 3 mm and 5 mm for ducts the widths or diameters of which are up to and including 300 mm and 760 mm and over respectively and, in the case of such ducts, the widths or diameters of which are between 300 mm and 760 mm having a thickness to be obtained by interpolation; suitably supported and stiffened; fitted with automatic fire dampers close to the boundaries penetrated; and insulated to "A-60" standard from the machinery spaces, galleys, vehicle spaces, ro-ro cargo spaces or special category spaces to a point at least 5 m beyond each fire damper; or 9.11.2 Constructed of steel suitable supported and stiffened in accordance with 9.11.1 and insulated to "A-60" standard throughout the accommodation spaces, service spaces or control stations; 9.11.3 Except that penetrations of main zone divisions shall also comply with the requirements of 9.14. 9.12 Ducts provided for the ventilation to accommodation spaces, service spaces or control stations shall not pass through machinery spaces of category A, galleys, vehicle spaces, ro-ro cargo spaces orspecialcategory spaces unless either complying with 9.12.1 or 9.12.2. 9.12.1 The ducts where they pass through a machinery space of category A, galley, vehicle space, ro-ro cargo space or special category space are constructed of steel, suitable supported and stiffened in accordance with 9.11.1 and automatic fire dampers are fitted close to the boundaries penetrated; and integrity of the machinery space, galley, vehicle space, ro-ro cargo space or special category space boundaries is maintained at the penetrations; or 9.12.2 The ducts where they pass through a machinery space of category A, galley, vehicle space, ro-ro cargo space or special category space are constructed of steel, suitable supported and stiffened in accordance with 9.11.1 are insulated to "A-60" standard within the machinery space, galley, vehicle space, ro-ro cargo space or special category space; 9.12.3 Except that penetrations of main zone division shall also comply with the requirements in 9.14. 9.13 Ventilation ducts with a free cross-sectional area exceeding 0,02 m2 passing through "B" class bulkheads shall be lined with steel sheet sleeves of 900 mm in length divided preferably into 450 mm on each side of the bulkheads unless the duct is of steel for this length. 9.14 Where in a passenger ship it is necessary that a ventilation duct passes through a main vertical zone division, a fail-safe automatic closing fire damper shall be fitted adjacent to the division. The damper shall also be capable of being manually closed from each side of the division. The operating position shall be readily accessible and be marked in red light-reflecting colour. The duct between the division and the damper shall be of steel or other equivalent material and, if necessary, insulated to comply with the requirements of 6.1. The damper shall be fitted on at least one side of the division with a visible indicator showing whether the damper is in the open position. 9.15 Power ventilationofaccommodationspaces,servicespaces,cargospaces, control stations and machinery spaces shall be capable of being stopped from an easily accessible position outside the space being served. This position should not be readily cut off in the event of a fire in the spaces served. The means provided for stopping the power ventilation of the machinery spaces shall be entirely separate from the means provided for stopping ventilation of other spaces. 9.16 Controlsforshuttingdowntheventilationfansshallbecentralizedinacontinuouslymannedcentralcontrol station. The ventilation fans shall be capable of reactivation by the crew at this location, whereby the control panels shall be capable of indicating closed or off status of fans. 9.17 Exhaust ducts shall be provided with suitably located hatches for inspection and cleaning,. The hatches shall be located near the fire damper. 9.18 Where public spaces span three or more open decks and contain combustibles such as furniture and enclosed spaces such as shops, offices and restaurants, the space shall be equipped with a smoke extraction system (see also Rules for Machinery Installations, Volume III, Section 12). BKI - Rules for Hull - 2014
- 353. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-13/48 10. Restriction of combustible materials 10.1 Except in cargo spaces, mail rooms, baggage rooms, saunas 8) or refrigerated compartments of service spaces, alllinings,grounds,draughtstops,ceilings andinsulations shallbeofnon-combustiblematerials.Partialbulkheadsordecks used to subdivide a space for utility or artistic treatment shall also be of non-combustible material. Linings,ceilingsandpartialbulkheadsordecksusedtoscreenortoseparateadjacentcabinbalconiesshallbeofnon-combustible material. 10.2 Vapour barriers and adhesives used in conjunction with insulation, as well as insulation of pipe fittings, for cold service systems need not be non-combustible but they shall be kept to the minimum quantity practicable and their exposed surfaces shall have low flame spread characteristics. 10.3 The following surfaces shall have low flame spread characteristics 9) : 10.3.1 exposedsurfacesincorridorsandstairwayenclosures,andofbulkheads,wallandceilingliningsinallaccommodation and service spaces (except saunas) and control stations; 10.3.2 concealed or inaccessible spaces in accommodation, service spaces and control stations. 10.4 The total volume of combustible facings, mouldings, decorations and veneers in any accommodation and service space shall not exceed a volume equivalent to 2,5 mm veneer on the combined area of the walls and ceilings. Furniture fixed tolinings,bulkheadsordecksneednotbeincludedinthecalculationofthetotalvolumeofcombustiblematerials.Thisapplies also to traditional wooden benches and wooden linings on bulkheads and ceilings in saunas. In the case of ships fitted with anautomaticsprinklersystem,theabovevolumemayincludesomecombustiblematerialusedforerectionof"C"classdivisions. 10.5 Combustible materials used on surfaces and linings covered by the requirements of 10.3 shall have a calorific value10) not exceeding 45 MJ/m2 of the area for the thickness used. This does notapply to surfaces of furniture fixed to linings or bulkheads as well as to traditional wooden benches and wooden linings on bulkheads and ceilings in saunas. 10.6 Furniture in stairway enclosures shall be limited to seating. It shall be fixed, limited to six seats on each deck in each stairway enclosure, be of restricted fire risk, and shall not restrict the passenger escape route. Furnitureshallnotbepermittedinpassengerandcrewcorridorsformingescaperoutesincabinareas.Lockersofnon-combustible material, providing storage for safety equipment, may be permitted within these areas. Drinking water dispensers and ice cube machines may be permitted in corridors provided they are fixed and do not restrict the width of the escape route. This applies as well to decorative flower arrangements, statues or other objects d’art such as paintings and tapestries in corridors and stairways. 10.7 Furnitureandfurnishingsoncabinbalconies shallcomply with the following, unless such balconies are protected by a fixed pressure water-spraying and fixed fire detection and fire alarm systems 10.7.1 case furniture shall be constructed entirely of approved non-combustible materials, except that a combustible veneer not exceeding 2 mm may be used on the working surface; 10.7.2 free-standing furniture shall be constructed with frames of non-combustible materials; 10.7.3 draperies and other suspended textile materials shall have qualities of resistance to the propagation of flame not inferior to those of wool having a mass of 0,8 kg/m2 11) ; 10.7.4 upholstered furniture shall have qualities of resistance to the ignition and propagation of flame12) and 8) Insulation materials used in saunas shall be of non-combustible material. 9) Reference is made to the Fire Test Procedure Code, Annex 1, Part 5, adopted by IMO by Resolution MSC 61(67). 10) The gross calorific value measured in accordance with ISO Standard 1716 - "Building Materials - Determination of Calorific Potential", should be quoted. 11) Reference is made to the Fire Test Procedure Code, Annex 1, Part 7, adopted by IMO by Resolution MSC 61(67). 12) Reference is made to the Fire Test Procedure Code, Annex 1, Part 8, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 354. B Section 22 - Structural Fire Protection on Board Seagoing Ships22-14/48 10.7.5 bedding components shall have qualities of resistance to the ignition and propagation of flame 13) . 10.8 Paints,varnishesandotherfinishesusedonexposedinteriorsurfaces,includingcabinbalconieswiththeexclusion of natural hard wood decking systems, shall not be capable of producing excessive quantities of smoke and toxic products 14) . 10.9 Primary deck coverings, if applied within accommodation and service spaces and control stations or if applied on cabin balconies, shall be of approved material which will not readily ignite, or give rise to smoke or toxic or explosive hazards at elevated temperatures 15) . 10.10 Wastereceptaclesshallbeconstructedofnon-combustiblematerialswithnoopeningsinthesidesorbottom. Containers ingalleys,pantries,bars,garbagehandlingorstoragespacesandincineratorroomswhichareintendedpurelyforthecarriage of wet waste, glass bottles and metal cans may be constructed of combustible materials. 11. Details of construction 11.1 Inaccommodationandservicespaces,controlstations,corridorsandstairways,airspacesenclosedbehindceilings, panellingor linings shall be suitably divided by close fittingdraught stops not more than 14 m apart. In the vertical direction, such enclosed air spaces, including those behind linings of stairways, trunks, etc. shall be closed at each deck. 11.2 The construction of ceilings and bulkheads shall be such that it will be possible, without impairing the efficiency of the fire protection, for the fire patrols to detect any smoke originating in concealed and inaccessible spaces. 11.3 Non-load bearing partial bulkheads separating adjacent cabin balconies shall be capable of being opened by the crew from each side for the purpose of fighting fires. 11.4 The cargo holds and machinery spaces shall be capable of being effectively sealed such as to prevent the inlet of air. Doors leading to machinery spaces of category A are to be provided with self-closing devices and 2 securing devices. Allothermachineryspaces,whichareprotectedbya gas fire extinguishingsystem,aretobeequippedwithself-closingdoors. 11.5 Helicopter decks shall be of a steel or steel equivalentfire-resistant construction. If the space below the helicopter deck forms the deckhead of a deckhouse or superstructure, it shall be insulated to "A-60" class standard. If an aluminium or other low melting metal construction will be allowed, the following provisions shall be satisfied: 11.5.1 If the platform is cantilevered over the side of the ship, after each fire on the ship or on the platform, the platform shall undergo a structural analysis to determine its suitability for further use. 11.5.2 Iftheplatformislocatedabovetheship'sdeckhouseorsimilarstructure,thefollowingconditionsshallbesatisfied: 11.5.2.1 The deckhouse top and bulkheads under the platform shall have no openings; 11.5.2.2 All windows under the platform shall be provided with steel shutters; 11.5.2.3 Therequiredfire-fightingequipmentshallbein accordance withthe requirementsofRulesforMachineryInstallations, Volume III, Section 12. 11.5.2.4 After each fire on the platform or in close proximity, the platform shall undergo a structural analysis to determine its suitability for further use. 11.6 Construction and arrangement of saunas 11.6.1 Theperimeter ofthesaunashallbeof“A”class boundariesandmayincludechangingrooms,showersand toilets. The sauna shall be insulated to A-60 standard against other spaces except those inside the perimeter and spaces of category [5], [9] and [10]. 13) Reference is made to the Fire Test Procedure Code, Annex 1, Part 9, adopted by IMO by Resolution MSC 61(67). 14) Reference is made to the Fire Test Procedure Code, Annex 1, Part 2, adopted by IMO by Resolution MSC 61(67). 15) Reference is made to the Fire Test Procedure Code, Annex 1, Part 6, adopted by IMO by Resolution MSC.61(67). BKI - Rules for Hull - 2014
- 355. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-15/48 11.6.2 Bathrooms with direct access to saunas may be considered as part of them. In such cases, the door between sauna and the bathroom need not comply with fire safety requirements. 11.6.3 The traditional wooden lining on the bulkheads and on the ceiling are permitted in the sauna. The ceiling above the oven shall be lined with a noncombustible plate with an air-gap of at least 30 mm. The distance from the hot surfaces to combustible materials shall be at least 500 mm or the combustible materials shall be suitably protected. 11.6.4 The traditional wooden benches are permitted to be used in the sauna. 11.6.5 The sauna door shall open outwards by pushing. 11.6.6 Electrically heated ovens shall be provided with a timer. 12. Means of escape 12.1 Unless expressly provided otherwise in this regulation, at least two widely separated and ready means of escape shall be provided from all spaces or group of spaces. Lifts shall not be considered as forming one of the required means of escape. 12.2 Doors in escape routes shall, in general, open in-way of the direction of escape, except that - individual cabin doors may open into the cabins in order to avoid injury to persons in the corridor when the door is opened, and - doors in vertical emergency escape trunks may open out of the trunk in order to permit the trunk to be used both for escape and access. 12.3 Stairways and ladders shall be arranged to provide readymeans of escape to the lifeboat and liferaft embarkation deck from all passenger and crew spaces and from spaces in which the crew is normally employed, other than machinery spaces. In particular, the following provisions shall be complied with: 12.3.1 Below the bulkhead deck, two means of escape, at least one of which shall be independent of watertight doors, shall be provided from each watertight compartment or similarly restricted space or group of spaces. Due regard being paid to the nature and location of spaces and to the number of persons who normally might be employed there, exceptions are possible, however, stairways shall not be less than 800 mm in clear width with handrails on both sides. 12.3.2 Above the bulkhead deck, there shall be at least two means of escape from each main vertical zone or similarly restricted space or group of spaces at least one of which shall give access to a stairway forming a vertical escape. 12.3.3 At least one of the means of escape required by paragraphs 12.1.1 and 12.1.2 shall consist of a readily accessible enclosed stairway, which shall provide continuous fire shelter from the level of its origin to the appropriate lifeboat and liferaft embarkation decks, or to the uppermost weather deck if the embarkation deck does not extend to the main vertical zonebeingconsidered.Inthelattercase,directaccesstotheembarkationdeckbywayofexternalopenstairwaysandpassageways shall be provided and shall have emergency lighting (see also Rules for Electrical Installations, Volume IV, Section 3 and 11)and slip-free surfaces under foot. Boundaries facing externalopenstairwaysandpassageways formingpartofanescape route and boundaries in such a position that their failure during a fire would impede escape to the embarkation deck shall havefireintegrity,includinginsulationvalues,inaccordancewiththeTables22.1and22.2.Thewidths,numberandcontinuity of escapes shall be as follows: 12.3.3.1 Stairways shall not be less than 900 mm in clear width. Stairways shall be fitted with handrails on each side. The minimum clear width of stairways shall be increased by 10 mm for every one person provided for in excess of 90 persons. The maximum clear width between handrails where stairways are wider than 900 mm shall be 1800 mm. The total number of persons to be evacuated by such stairways shall be assumed to be two thirds of the crew andthe total number of passengers in the areas served by such stairways 16) . 12.3.3.2 All stairways sized for more than 90 persons shall be aligned fore and aft. 12.3.3.3 Doorways and corridors and intermediate landings included inmeans of escape shall besizedinthesamemanner as stairways. The aggregate width of stairway exit doors to the assembly station shall not be less than the aggregate width 16) Reference is made to the Fire Safety Systems Code, adopted by IMO by Resolution MSC 98 (73). BKI - Rules for Hull - 2014
- 356. B Section 22 - Structural Fire Protection on Board Seagoing Ships22-16/48 of stairways serving this deck. 12.3.3.4 Stairways shall not exceed 3,5 m in vertical rise without the provision of a landing and shall not have an angle of inclination greater than 45E. 12.3.3.5 Landings at each deck level shall be not less than 2 m2 in area and shall increase by 1 m2 for every 10 persons provided for in excess of 20 persons but need not exceed 16 m2 , except for those landings servicing public spaces having direct access onto the stairway enclosure. 12.3.4 Stairways serving only a space and a balcony in that space shall not be considered as forming one of the means of escape. 12.3.5 Acorridor,lobby,orpartofacorridorfromwhichthereisonlyonerouteofescapeshallnotbepermitted.Dead–end corridorsusedinserviceareaswhicharenecessaryforthepracticalutilityoftheship,suchasfueloilstationsandathwartship supply corridors, shall be permitted, provided such dead-end corridors are separated from crew accommodation areas and are inaccessible from passenger accommodation areas. Also, a part of the corridor that has a depth not exceeding its width is considered a recess or local extension and is permitted. 12.3.6 In addition to the emergency lighting (see also Rules for Electrical Installations, Volume IV, Section 3 and 10), the means of escape including stairways and exits, shall be marked by lighting or photoluminescent strip indicators placed not more than 0,3 m above the deck at all points of the escape route including angles and intersections. The marking shall enable passengers to identify all the routes of escape and readily identify the escape exits. If electric illumination is used, it shall be supplied by the emergency source of power and it shall be so arranged that the failure of any single light or cut in a lighting strip, will not result in the marking being ineffective. Additionally, all escape route signs and fire equipment locationmarkingsshallbeofphotoluminescentmaterialormarkedbylighting. Suchlightingorphotoluminescentequipment shall be of an approved type16) . 12.3.7 The requirement of 12.3.6 shall also apply to the crew accommodation areas. 12.3.8 PublicSpacesspanningthree ormoredecksandcontaincombustiblessuchas furniture and enclosed spaces such as shops, offices and restaurants shall have at each level withinthe space two means of escape, one of which shall have direct access to an enclosed vertical means of escape as mentioned under 12.3.3. 12.4 Ifaradiotelegraphstationhasnodirectaccesstotheopendeck, twomeansofescapefromoraccesstosuchstation shall be provided, one of which may be a porthole or window of sufficient size or another means. 12.5 In special category spaces the number and disposition of the means of escape both below and above the bulkhead deck shall be satisfactory as mentioned under 12.3.1, .2 and .3. 12.6 Two means of escape shall be provided from each machinery space. In particular, the following provisions shall be complied with: 12.6.1 Where the space is below the bulkhead deck the two means of escape shall consist of either: 12.6.1.1 Two sets of steel ladders as widely separated as possible, leading to doors in the upper part of the space similarly separated and from which access is provided to the appropriate lifeboat and liferaft embarkation decks. One of these ladders shall be located within a protected enclosure having fire integrity, including insulation values, in accordance with the Tables 22.1and22.2foracategory[2] space,fromthelowerpartofthespacetoasafepositionoutsidethespace.Self-closing doors of the same fire integrity standards shall be fitted in the enclosure. The ladder shall be fixed in such a way that heat isnottransferredintotheenclosurethroughnon-insulatedfixingpoints.Theprotectedenclosureshallhaveminimuminternal dimensions of at least 800 mm × 800 mm, and shall have emergency lighting provisions, or 12.6.1.2 One steel ladder leading to a door in the upper part of the space from which access is provided to the embarkation deck and additionally, in the lower part of the space and in a position well separated from the ladder referred to, a steel door capable of being operated from each side and which provides access to a safe escape route from the lower part of the space to the embarkation deck. 12.6.2 Where the space is above the bulkhead deck, two means of escape shall be as widely separated as possible and the doors leading from such means of escape shall be in a position from which access is provided to the appropriate lifeboat and liferaft embarkation decks. Where such escapes require the use of ladders these shall be of steel. BKI - Rules for Hull - 2014
- 357. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-17/48 12.6.3 A ship of a gross tonnage less than 1000 may be dispensed with one of the means of escape, due regard being paid to the width and disposition of the upper part of the space; and a ship of a gross tonnage of 1000 and above, may be dispensed with one means of escape from any such space so long as either a door or a steel ladder provides a safe escape routetotheembarkationdeck,dueregardbeingpaidtothenatureandlocationofthespaceandwhetherpersonsarenormally employed in that space. 12.6.4 In the steering gear room, a second means of escape shall be provided when the emergency steering position is located in that space unless there is direct access to the open deck. 12.6.5 One oftheescaperoutesfromthemachineryspaceswherethecrewisnormallyemployed shall avoid direct access to any special category space. 12.6.6 Two means of escape shall be provided from a machinery control room within a machinery space, at least one of which shall provide continuous fire shelter to a safe position outside the machinery space. 12.6.7 A helideck shall be provided with both a main and an emergency means of escape and access for fire fighting and rescue personnel. These shall be located as far as apart from each other as is practicable and preferably on opposite sides of the helideck. 12.7 Additional requirements for ro-ro passenger ships 12.7.1 Handrailsorotherhandholdsshallbeprovidedinallcorridorsalongtheentireescaperoute,sothatafirmhandhold is available every step of the way, where possible, to the assembly stations and embarkation stations. Such handrails shall be provided on both sides of longitudinal corridors more than 1,8 m in width and transverse corridors more than 1 m in width. Particular attention shall be paid to the need to be able to cross lobbies, atriums and other large open spaces along escape routes. Handrails and other handholds shall be of such strength as to withstand a distributed horizontal load of 750 N/m applied in the direction of the centre of the corridor or space, and a distributed vertical load of 750 N/m applied in the downward direction. The two loads need not be applied simultaneously. 12.7.2 Escape routes shall be provided from every normally occupied space on the ship to an assembly station. These escape routes shall be arranged so as to provide the most direct route possible to the assembly station and shall be marked with relevant symbols. 12.7.3 Whereenclosedspacesadjoinanopendeck,openingsfromtheenclosedspacetotheopendeckshall,wherepracticable, be capable of being used as an emergency exit. 12.7.4 Decks shall be sequentially numbered, starting with "1" at the tank top or lowest deck. These numbers shall be prominentlydisplayedatstairlandingsandliftlobbies.Decksmayalsobenamed,butthedecknumbershallalwaysbedisplayed with the name. 12.7.5 Simple"mimic"plansshowingthe"youarehere"positionandescaperoutesmarkedbyarrows,shallbeprominently displayed on the inside of each cabin door and in public spaces. The plan shall show the directions of escape, and shall be properly oriented in relation to its position on the ship. 12.7.6 Cabin and stateroom doors shall not require keys to unlock them from inside the room. Neither shall there be any doors along any designed escape route which require keys to unlock them when moving in the direction of escape. 12.7.7 The lowest 0,5 m of bulkheads and other partitions forming vertical divisions along escape routes shall be able to sustain a load of 750 N/m to allow them to be used as walking surfaces from the side of the escape route with the ship at large angles of heel. 12.7.8 The escape route from cabins to stairway enclosures shall be as direct as possible, with a minimum number of changes in direction. It shall not be necessary to cross from one side of the ship to the other to reach an escape route. It shall notbenecessarytoclimbmorethantwodecksupordowninordertoreachanassemblystationoropendeckfromanypassenger space. 12.7.9 Externalroutesshallbeprovidedfromopendecks,referredtoinparagraph12.7.8,tothesurvivalcraftembarkation stations. BKI - Rules for Hull - 2014
- 358. B Section 22 - Structural Fire Protection on Board Seagoing Ships22-18/48 12.7.10 Escape routes are to be evaluated by an evacuation analysis early in the design process 17) . Theanalysisshallbeusedtoidentifyandeliminate,asfaraspracticable,congestionwhichmaydevelopduringanabandonment, due to normal movement of passengers and crew along escape routes, including the possibility that crew may need to move along these routes in a direction opposite the movement of passengers. In addition, the analysis shall be used to demonstrate the escape arrangements are sufficiently flexible to provide for the possibility that certain escape routes, assembly stations, embarkation stations or survival craft may not be available as a result of a casualty. 12.7.11 Designatedwalkwaystothemeansofescapewithabreadthofatleast600mmshallbeprovidedinspecial category and open ro-ro spaces to which any passengers carried have access. 12.7.12 At least two means of escape shall be provided in ro-ro spaces where the crew are normally employed. The escape routes shall provide safe escape to the lifeboat and liferaft embarkation decks and shall be located at the fore and aft ends of the space. 13. Fixed fire detection and fire alarm systems and automatic sprinkler, fire detection and fire alarm systems. 13.1 Any ship shall be equipped with: 13.1.1 Anautomaticsprinkler,firedetectionandfirealarmsysteminallservicespaces,controlstationsandaccommodation spaces, including corridors and stairways (see also Rules for Machinery Installations, Volume III, Section.12); and 13.1.2 A fixed fire detection and alarm system so installed and arranged as to provide smoke detection in service spaces, control stations and accommodation spaces, including corridors and stairways (see also Rules for Machinery Installations, Volume III, Section 12). 13.2 Controlstationswherewatermaycausedamagetoessentialequipmentmaybefittedwithafixedfire-extinguishing system of another type (see also Rules for Machinery Installations, Volume III, Section 12). 13.3 Cabinbalconiesshallbeequippedwithafixedfiredetectionandfirealarmsystemandafixedpressure water-spraying system(seealsoRules for Machinery Installations, Volume III, Section 12), whenfurniture andfurnishingsonsuchbalconies are not complying with 10.7. 13.4 Smoke detectors need not be fitted in private bathrooms and galleys. Spaces having little or no fire risk such as voids, public toilets andsimilar spacesneednotbefittedwithanautomaticsprinkler,orfixedfiredetectionandalarmsystem. 14. Protection of vehicle, special category and ro-ro spaces 14.1 The subdivision of such spaces in main vertical zones would defeat their intended purpose. Therefore equivalent protection shall be obtained in such spaces on the basis of a horizontal zone concept. A horizontal zone may include special category and ro-ro spaces on more than one deck provided that the total overall clear height for vehicles does not exceed 10 m, whereas the total overall clear height is the sum of distances between deck and web frames of the decks forming the horizontal zone. 14.2 Structural Protection The boundary bulkheads and decks of special category spaces and ro-ro spaces shall be insulated to "An60" class standard. However, where a category 4.3 [5],4.3 [9]or 4.3 [10] space is on one side of the division the standard may be reduced to "A-0". Where fuel oil tanks are below a special category space, the integrity of the deck between such spaces may be reduced to "A-0" standard. Indicators shall be provided on the navigating bridge which shall indicate when any fire door leading to or from the special category space is closed. 14.3 Fixed fire-extinguishing system 14.3.1 Vehicle spaces and ro-ro spaces which are not special category spaces and are capable of being sealed from a location outside of the cargo spaces shall be fitted with a fixed gas fire-extinguishing system of an approved type (see also Rules for Machinery Installations, Volume III, Section 12). 14.3.2 Ro-roandvehiclespacesnotcapableofbeingsealedandspecialcategoryspacesshallbefittedwithafixed pressure 17) Reference is made to the Interim Guidelines for evacuation analyses for new and existing passenger ships adopted by IMO by MSC/Circ. 1238. BKI - Rules for Hull - 2014
- 359. Section 22 - Structural Fire Protection on Board Seagoing Ships B 22-19/48 water spraying system for manual operation of an approved type (see also Rules for Machinery Installations, Volume III, Section 12). 14.4 Ventilation system There shall be provided an effective power ventilation system for the special category spaces and closed ro-ro and vehicle spacessufficienttogiveatleast10airchangesperhour.Beyond this, a higher air exchange rate is required during the period of loading and unloading. The system for such spaces shall be entirely separated from other ventilation systems and shall be operating at all times when vehicles are in such spaces. Ventilation ducts serving such spaces capable of being effectively sealed shall be separated for each such space. The system shall be capable of being controlled from a position outside such spaces. The ventilation shall be such as to prevent air stratification and the formation of air pockets. Means shall be provided to indicate on the navigating bridge any loss or reduction of the required ventilating capacity. Arrangements shall be provided to permit a rapid shut-down and effective closure of the ventilation system in case of fire, taking into account the weather and sea conditions. Ventilation ducts, including dampers, within a common horizontal zone shall be made of steel. Ducts passing through other horizontal zones or machinery spaces shall be "A-60" class steel ducts complying with 9.11.1 and 9.11.2. Permanent openings in the side plating, the ends or deckhead of the space shall be so situated that a fire in the cargo space does not endanger stowage areas and embarkation stations for survival craft and accommodation spaces, service spaces and control stations in superstructures and deckhouses above the cargo space. 14.5 Fire detection Thereshallbeprovidedafixedfiredetectionandfirealarmsystemofanapprovedtype(seealsoRulesforMachineryInstallations, Volume III, Section 12). A sample extraction smoke detection system of an approved type (see also Rules for Machinery Installations, Volume III, Section 12) may be accepted as equivalent, except for open ro-ro spaces, open vehicle spaces and special category spaces. An efficient fire patrol system shall be maintained in special category spaces. In case of a continuous fire watch at all times during the voyage, a fixed fire detection and alarm system is not required therein. 15. Special arrangements in machinery spaces of category A 15.1 The number of skylights, doors, ventilators, openings in funnels to permit exhaust ventilation and other openings to machinery spaces shall be reduced to a minimum consistent with the needs of ventilation and the proper and safe working of the ship. 15.2 Skylights shall be of steel and shall not contain glass panels. Suitable arrangements shall be made to permit the release of smoke in the event of fire, from the space to be protected. The normal ventilation systems may be acceptable for this purpose. 15.3 Means of control shall be provided for permitting the release of smoke and such controls shall be located outside thespaceconcernedsothat,in theeventoffire,theywillnotbe cut off from the space they serve. The controls shallbesituated at one control position or grouped in as few positions as possible. Such positions shall have safe access from the open deck. 15.4 Such doors other than power-operated watertight doors shall be arranged so that positive closure is assured in case of fire in the space, by power-operated closing arrangements orbythe provisionofself-closing doors capable of closing against an inclination of 3,5E opposing closure and having a fail-safe hook-back facility, provided with a remotely operated releasedevice.Doorsforemergencyescapetrunksneednotbefittedwithafail-safehold-backfacilityandaremotelyoperated release device. 15.5 Means of control shall be provided for closing power- operated doors or actuating release mechanism on doors other than power-operated watertight doors. The control shall be located outside the space concerned, where they will not be cut off in the event of fire in the space it serves. The means of control shall be situated at one control position or grouped in as few positions as possible having direct access and safe access from the open deck. 15.6 Windows shall not be fitted in machinery space boundaries. This does not preclude the use of glass in control rooms within the machinery spaces. BKI - Rules for Hull - 2014
- 360. B, C Section 22 - Structural Fire Protection on Board Seagoing Ships22-20/48 15.7 The floor plating of normal passageways shall be made of steel. 16. Special requirements for ships carrying dangerous goods 16.1 Ventilation Adequate power ventilation shall be provided in enclosed cargo spaces. The arrangement shall be such as to provide for at least six air changes per hour in the cargo space based on an empty cargo space and for removal of vapour from the upper or lower parts of the cargo space, as appropriate. The fans shall be such as to avoid the possibility of ignition of flammable gas air mixtures. Suitable wire mesh guards shall be fitted over inlet and outlet ventilation openings. 16.2 Insulation of machinery space boundaries BulkheadsformingboundariesbetweencargospacesandmachineryspacesofcategoryAshallbeinsulatedto"A-60"standard, unless the dangerous goods are stowed at least 3 m horizontally away from such bulkheads. Other boundaries between such spaces shall be insulated to "A-60" standard. 16.3 Miscellaneous items The kind and extent of the fire extinguishing equipment are defined in Rules for Machinery Installations, Volume.III, Section 12. Electrical apparatus and cablings are to meet the requirements of Rules for Electrical Installations, Volume.IV, Section 16. C. Regulations on Fire Protection for Passenger Ships carrying not more than 36 Passengers 1. Materials 1.1 Thehull,decks,structuralbulkheads,superstructuresanddeckhousesaretobeofsteelorotherequivalentmaterials (aluminium alloy suitably insulated). 1.2 Components made from aluminium alloys require special treatment, with regard to the mechanical properties of the material in case of temperature increase. In principle, the following is to be observed : 1.2.1 The insulation of "A" or "B" class divisions shall be such that the temperature of the structural core does not rise more than 200EC above the ambient temperature at any time during the applicable fire exposure to the standard fire test. 1.2.2 Special attention shall be given to the insulation of aluminium alloy components of columns, stanchions and other structural members required to support lifeboat and liferaft stowage, launching and embarkation areas, and "A" and "B" class divisions to ensure: that for such members supporting lifeboat and liferaft areas and "A"class divisions, the temperature rise limitation specified in 1.2.1 shall apply at the end of one hour;andthatforsuchmembers required to support "B"class divisions, the temperature rise limitation specified in 1.2.1 shall apply at the end of half an hour. 1.2.3 Crowns and casings of machinery spaces of category A shall be of steel construction and be insulated as required by Table 22.3 as appropriate. Openings therein, if any, shall be suitably arranged and protected to prevent the spread of fire. 2. Main vertical zones and horizontal zones 2.1 The hull, superstructure and deckhouses in way of accommodation and service spaces are to be subdivided into main vertical zones the average length and width of which on any deck is generally not to exceed 40 m. Subdivision is to be effected by "A" class divisions. As far as practicable, the bulkheads forming the boundaries of the main vertical zones above the bulkhead deck shall be in line with watertight subdivision bulkheads situated immediately below the bulkhead deck. The length and width of main verticalzonesmaybeextendedtoamaximumof48minordertobringtheendsofmainverticalzonestocoincidewithsubdivision watertight bulkheads or in order to accommodate a large public space extending for the whole length of the main vertical BKI - Rules for Hull - 2014
- 361. Section 22 - Structural Fire Protection on Board Seagoing Ships C 22-21/48 zone provided that the total area of the main vertical zone is not greater than 1600 m2 on any deck. The length or width of a main vertical zone is the maximum distance between the furthermost points of the bulkheads bounding it. The divisions are to extend from deck to deck and to the shell or other boundaries and shall have insulation values in accordance with Table 22.3. At the edges insulating bridges are to be provided where required. 2.2 Where a main vertical zone is subdivided by horizontal "A" class divisions into horizontal zones for the purpose of providing an appropriate barrier between sprinklered and non-sprinklered zones of the ship the divisions shall extend between adjacent main vertical zone bulkheads and to the shell or exterior boundaries of the ship and shall be insulated in accordance with the fire insulation and integrity values given in Table 22.4. 2.3 On ships designed for special purposes (automobile or railroad car ferries), where the provision of main vertical zone bulkheads would defeat the purpose for which the ships is intended, equivalent means for controlling and limiting a fire are to be provided and specifically approved. Service spaces and ship stores shall not be located on ro-ro decks unless protected in accordance with the applicable regulations. 3. Bulkheads within main vertical zones 3.1 All bulkheads within accommodation and service spaces which are not required to be "A" class divisions shall be at least "B" class or "C" class divisions as prescribed in Table 22.3. All such divisions may be faced with combustible materials. 3.2 All corridor bulkheads where not required to be "A" class shall be "B" class divisions which shall extend from deck to deck. Exceptions may be permitted when continuous "B" class ceilings are fitted on both sides of the bulkhead or when the accommodations are protected by an automatic sprinkler system. 3.3 All bulkheads required to be "B" class division, except corridor bulkheads prescribed in 3.2, shall extend from deck to deck and to the shell or other boundaries unless the continuous "B" class ceilings or linings fitted on both sides of thebulkheadsareatleastofthesamefireresistanceasthebulkhead,inwhichcasethebulkheadmayterminateatthecontinuous ceiling or lining. 4. Fire integrity of bulkheads and decks 4.1 In addition to complying with the specific provisions for fire integrity of bulkheads and deck mentioned elsewhere in this Section, the minimum fire integrity of all bulkheads and decks shall be as prescribed in Tables 22.3 to 22.4. 4.2 The following requirements shall govern application of the tables : Table 22.3 shall apply to bulkheads, separating adjacent spaces. Table 22.4 shall apply to deck, separating adjacent spaces. 4.3 Forthepurposeofdeterminingtheappropriatefireintegritystandardstobeappliedtoboundariesbetweenadjacent spaces, such spaces are classified according to their fire risk as shown in the following categories [1] to [11]. Where the contents and use of a space are such that there is a doubt as to its classification for the purpose of this regulation, or where it is possible to assign two or more classifications to a space, it shall be treated as a space within the relevant category having the most stringent boundary requirements. Smaller, enclosed rooms within a spopenings to that space are to be considered separate spaces. The fire integrity of the boundary bulkheads of such smaller rooms shall be as prescribed in Tables 22.3 and 22.4. The title of each category is intended to be typical rather than restrictive. The number in parentheses preceding each category refers to the applicable column or row number in the Tables. BKI - Rules for Hull - 2014
- 362. C Section 22 - Structural Fire Protection on Board Seagoing Ships22-22/48 Table 22.3 Fire integrity of bulkheads separating adjacent spaces Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] Control stations [1] A-03 A-0 A-60 A-0 A-15 A-60 A-15 A-60 A-60 7 A-60 Corridors [2] C5 B-05 A-01 B-05 B-05 A-60 A-0 A-0 A-15 A-04 7 A-15 Accommodation spaces [3] C5 A-01 B-05 B-05 A-60 A-0 A-0 A-15 A-04 7 A-30 A-04 Stairways [4] A-01 B-05 A-01 B-05 A-60 A-0 A-0 A-15 A-04 7 7 A-15 Service spaces (low risk) [5] C5 A-60 A-0 A-0 A-0 7 A-0 Machinery spaces of category A [6] 7 A-0 A-0 A-60 7 A-60 Other machinery spaces [7] A-02 A-0 A-0 7 A-0 Cargo spaces [8] 7 A-0 7 A-0 Service spaces (high risk) [9] A-0 7 A-30 Open decks [10] - A-0 Specialcategory spacesandro-rocargo spaces [11] A-0 Notes to be applied to Tables 22.3 and 22.4, as appropriate 1. For clarification as to which applies see 3 and 5 2. Wherespaces are of the same numerical category and superscript2appears,abulkheadordeckoftheratingsshowninthetablesinonly required when the adjacent spaces are for a different purpose, e.g. in category [9]. A galley next to a galley does not require a bulkhead but a galley next to a paint room requires an "A-0" bulkhead. 3. Bulkheads separating the wheelhouse and chartroom from each other may be "B-0" rating. 4. Indeterminingtheapplicablefireintegritystandardofaboundarybetweentwospaceswhichareprotectedbyanautomaticsprinklersystem, the lesser of the two values given in the tables shall apply. 5. For the application of 2.1 "B-0" and "C" , where appearing in Table 22.3 shall be read as "A-0". 6. Fire insulation need not be fitted if the machinery space of category [7], in the opinion of the Administration, has little or no fire risk. 7. Where a 7 appears in the tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class standard. For the application of 2.1 a 7, where appearing in Table 22.4 except for categories 8 and 10, shall be read as "A-0". BKI - Rules for Hull - 2014
- 363. Section 22 - Structural Fire Protection on Board Seagoing Ships C 22-23/48 Table 22.4 Fire integrity of decks separating adjacent spaces Space above Space below [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] Control stations [1] A-0 A-0 A-0 A-0 A-0 A-60 A-0 A-0 A-0 7 A-30 Corridors [2] A-0 7 7 A-0 7 A-60 A-0 A-0 A-0 7 A-0 Accommodation spaces [3] A-60 A-0 7 A-0 7 A-60 A-0 A-0 A-0 7 A-30 A-04 Stairways [4] A-0 A-0 A-0 7 A-0 A-60 A-0 A-0 A-0 7 A-0 Service spaces (low risk) [5] A-15 A-0 A-0 A-0 7 A-60 A-0 A-0 A-0 7 A-0 Machinery spaces of category A [6] A-60 A-60 A-60 A-60 A-60 7 A-606 A-30 A-60 7 A-60 Other machinery spaces [7] A-15 A-0 A-0 A-0 A-0 A-0 7 A-0 A-0 7 A-0 Cargo spaces [8] A-60 A-0 A-0 A-0 A-0 A-0 A-0 7 A-0 7 A-0 Service spaces (high risk) [9] A-60 A-30 A-04 A-30 A-04 A-30 A-04 A-0 A-60 A-0 A-0 A-0 7 A-30 Open decks [10] 7 7 7 7 7 7 7 7 7 - A-0 Special category spaces and ro-ro cargo spaces [11] A-60 A-15 A-30 A-04 A-15 A-0 A-30 A-0 A-0 A-30 A-0 A-0 See note under Table 22.3 [1] Control stations Spaces containing emergency sources of power and lighting.Wheelhouseandchart-room.Spacescontainingtheship's radio equipment. Fire control stations. Control room for propulsion machinery when located outside the propulsion machinery space. Spaces containing centralized fire alarm equipment. [2] Corridors Passenger and crew corridors and lobbies. [3] Accommodation spaces Spaces used for public spaces, lavatories, cabins, offices, hospitals, cinemas, games and hobby rooms, barber ships, pantries containing no cooking appliances and similar spaces. [4] Stairways Interior stairways, lifts, totally enclosed emergency escape trunks and escalators (other than those wholly contained within machinery spaces) and enclosures thereto. In this connection, a stairways which is enclosed only at one level shall be regarded as part of the space from which it is not separated by a fire door. [5] Service spaces (low risk) Lockers and store-rooms not having provisions for the storage of flammable liquids and having areas less than 4 m2 and drying rooms and laundries. [6] Machinery spaces of category A. Spaces and trunks to such spaces which contain: internal combustion machinery used for main propulsion; or BKI - Rules for Hull - 2014
- 364. C Section 22 - Structural Fire Protection on Board Seagoing Ships22-24/48 internalcombustionmachineryusedforpurposesotherthanmainpropulsionwheresuchmachineryhasintheaggregate a total power output of not less than 375 kW; or any oil-fired boiler or oil fuel unit. [7] Other machinery spaces Spaces, other than machinery spaces of category A, containing propulsion machinery, boilers, oil fuel units, steam andinternalcombustionengines,generatorsandmajorelectricalmachinery,oilfillingstations, refrigerating,stabilizing, ventilation and air conditioning machinery, and similar spaces,and trunks to such spaces. Electrical equipment rooms (auto-telephone exchange, air-conditioning duct spaces) [8] Cargo spaces All spaces used for cargo (including cargo oil tanks) and trunkways and hatchways to such spaces, other than special category spaces. [9] Service spaces (high risk) Galleys, pantries containing cooking appliances, paint and lamp rooms, lockers and store-rooms having areas of 4 m2 or more, spaces for the storage of flammable liquids, saunas and workshops other than those forming part of the machinery spaces. [10] Open decks Open deck spaces and enclosed promenades having little or nofire risk. Enclosed promenades shall have no significant firerisk,meaningthatfurnishingshouldberestrictedtodeckfurniture.Inaddition,suchspacesshallbenaturallyventilated by permanent openings. Air spaces (the space outside superstructures and deckhouses). [11] Special category spaces and ro-ro cargo spaces 4.4 Continuous "B" class ceilings or linings, in association with the relevant decks or bulkheads, may be accepted as contributing wholly or in part, to the required insulation and integrity of a division. 4.5 See B.4.5. 5. Protection of stairways and lifts in accommodation and service spaces. 5.1 Allstairwaysinaccommodationandservicespacesaretobeofsteelframeorotherapprovedequivalentconstruction; they are to be arranged within enclosures formed by "A" Class divisions, with effective means of closure for all openings. The following exceptions are admissible : 5.1.1 Astairwayconnectingonlytwodecksneednotbeenclosed,providedthattheintegrityofthepierceddeckismaintained by suitable bulkheads or doors at one of the two decks. When a stairway is closed at one 'tweendeck space, the stairway enclosed shall be protected in accordance with the tables for decks. 5.1.2 Stairways fitted within a closed public space need not be enclosed. 5.2 Stairway enclosures are to be directly accessible from the corridors and of sufficient area to prevent congestion, having in mind the number of persons likely to use them in an emergency. Within the perimeter of such stairway enclosures, onlypublicspaces,lockersofnon-combustiblematerialprovidingstorageforsafetyequipmentandopeninformationcounters are permitted. Only public spaces, corridors, public toilets, special category spaces, other escape stairways required by 12.1.3 and external areas are permitted to have direct access to these stairway enclosures. Small corridors or lobbies used to separate an enclosed stairway from galleys or main laundries may have direct access to the stairway provided they have a minimum deck area of 4,5 m², a width of no less than 900 mm and contain a fire hose station. 5.3 Lift trunks shall be so fitted as to prevent the passage of smoke and flame from one ‘ween deck to another and shall be provided with means of closing so as to permit the control of draught and smoke. 6. Openings in "A" class divisions 6.1 Where "A"class divisions are penetratedfor the passageofelectriccables, pipes, trunks,ducts, etc, or for girders, BKI - Rules for Hull - 2014
- 365. Section 22 - Structural Fire Protection on Board Seagoing Ships C 22-25/48 beams or other structural members, arrangements shall be made to ensure that the fire resistance is not impaired, subject to the provisions of 6.6. 6.2 All openings in the divisions are to be provided with permanently attached means of closing which shall be at least as effective for resisting fire as the divisions 18) . This does not apply for hatches between cargo, special category, store and baggage spaces and between such spaces and the weather decks. 6.3 The constructionofalldoors and door frames in "A"class divisions, with the means of securing them when closed, shall provide resistance to fire as well as to the passage of smoke and flame, equivalent to that of the bulkheads in which the doors are situated 18) . Such doors and door frames shall be approved by BKI and constructed of steel or other equivalent material. Watertight doors need not be insulated. 6.4 It shall be possible for each door to be opened and closed from each side of the bulkhead by one person only. 6.5 Firedoorsinmainverticalzonebulkheads,galleyboundariesandstairwayenclosuresother than power-operated watertight doors and those which are normally locked, shall satisfy the following requirements: 6.5.1 The doors shall be self-closing and be capable of closing against an angle of inclination of up to 3,5° opposing closure. 6.5.2 The approximate time of closure for hinged fire doors shall be no more than 40 s and no less than 10 s from the beginning of their movement with the ship in upright position. The approximate uniform rate of closure for sliding fire doors shall be of no more than 0,2 m/s and no less than 0,1 m/s with the ship in the upright position. 6.5.3 The doors, except those for emergency escape trunks shall be capable of remote release from the continuously manned central control station, either simultaneously or in groups and shall be capable of release also individually from apositionatbothsidesofthedoor.Releaseswitchesshallhaveanon-offfunctiontopreventautomaticresettingofthesystem. 6.5.4 Hold-back hooks not subject to central control station release are prohibited. 6.5.5 A door closed remotely from the central control station shall be capable of being re-opened at both sides of the doorbylocalcontrol.Aftersuchlocalopening,thedoorshallautomaticallycloseagain(seealsoRulesforElectricalInstallations, Volume IV, Section 9) 6.5.6 Indication shall be provided at the fire door indicator panel in the continuously manned central control station whether each of the remote-released doors are closed. 6.5.7 The release mechanism shall be so designed that the door will automatically close in the event of disruption of the control system or main source of electric power. 6.5.8 Local power accumulators for power-operated doors shall be provided in the immediate vicinity of the doors to enable the doors to be operated after disruption of the control system or main source of electric power at least ten times (fully opened and closed) using the local controls (see also Rules for Machinery Installations, Volume III, Section 14). 6.5.9 Disruption of the control system or main source of electric power at one door shall not impair the safe functioning of the other doors. 6.5.10 Remote-released sliding or power-operated doors shall be equipped with an alarm that sounds for at least 5 s but no more than 10 s after the door is released from the central control station and before the door begins to move and continue sounding until the door is completely closed. 6.5.11 A door designed to re-open upon contacting an object in its path shall re-open not more than 1 m from the point of contact. 6.5.12 Double-leaf doors equipped with a latch necessary to their fire integrity shall have a latch that is automatically activated by the operation of the doors when released by the control system. 6.5.13 Doors giving direct access to special category spaces which are power-operated and automatically closed need not be equipped with the alarms and remote release mechanisms required in 6.5.3 and 6.5.10. 18) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 366. C Section 22 - Structural Fire Protection on Board Seagoing Ships22-26/48 6.5.14 The components of the local control system shall be accessible for maintenance and adjusting. 6.5.15 Power-operated doors shall be provided with a control system of an approved type which shall be able to operate in case of fire19) . This system shall satisfy the following requirements: 6.5.15.1 the control system shall be able to operate the door at the temperature of at least 200 °C for at least 60 min, served by the power supply; 6.5.15.2 the power supply for all other doors not subject to fire shall nor be impaired; and 6.5.15.3 at temperatures exceeding 200 °C the control system shall be automatically isolated from the power supply and shall be capable of keeping the door closed up to at least 945 °C. 6.6 Whereaspace is protected by anautomatic sprinkler system or fittedwithacontinuous"B"classceiling,openings in decks not forming steps in main vertical zones nor bounding horizontal zones shall be closed reasonably tight and such decks shall meet the "A" class integrity requirements in so far as is reasonable and practicable. 6.7 Therequirementsfor"A"classintegrityoftheouterboundariesofashipshallnotapplytoglasspartitions,windows andsidescuttles,providedthatthereisnorequirementforsuchboundariestohave"A"classintegrityin8.3.Therequirements for "A"class integrity of the outer boundaries of the ship shall not apply to exterior doors, except for those in superstructures anddeckhousesfacinglife-savingappliances, embarkationandexternal muster station areas, external stairs and open decks used for escape routes. Stairway enclosure doors need not meet this requirement. 6.8 Exceptforwatertight, weathertightdoors(semi-watertightdoors),doorsleadingtotheopendeckanddoorswhich need reasonably gastight, all "A" class doors located in stairways, public spaces and main vertical zone bulkheads in escape routes shall be equipped with a self-closing hose port of material, construction and fire resistance which is equivalent to the door into which it is fitted, and shall be a 150 mm square clear opening with the door closed and shall be inset into the lower edge of the door, opposite the door hinges, or in the case of sliding doors, nearest the opening. 7. Openings in "B" class divisions 7.1 Where "B" class divisions are penetrated for the passage of electric cables, pipes, trunks, ducts, etc, or for the fittingofventilationterminals,lightingfixturesandsimilardevices,arrangementshallbemade toensurethatthefireresistance is not impaired. See also B.7.1. 7.2 Doors and door frames in "B"class divisions and means of securing them shall provide a method of closure which shall have resistance to fire equivalent to that of divisions20) except that ventilation openings may be permitted in the lower portion of such doors. Where such opening is in or under a door the total net area of any such opening or openings shall not exceed 0,05 m2 . Alternatively, a non-combustible air balance duct between the cabin and the corridor, and located below the sanitary unit is permitted where the cross-sectional area of the duct does not exceed 0,05 m². All ventilation openings shall be fitted with a grill made of non-combustible material. Doors shall be non-combustible and approved by BKI. 7.3 Cabin doors in "B" class division shall be of a self closing type. Hold-backs are not permitted. 7.4 Therequirementsfor"B"classintegrityoftheouterboundariesofashipshallnotapplytoglasspartitions,windows and sidescuttles. Similarly, the requirements for "B" class integrity shall not apply to exterior doors in superstructures and deckhouses. 7.5 Where an automatic sprinkler system is fitted: 7.5.1 Openingsindecksnotformingstepsinmainverticalzonesnorboundinghorizontalzonesshallbe closedreasonably tight and such decks shall meet the "B" class integrity requirements in so far as is reasonable and practicable and 7.5.2 Openings in corridor bulkheads of "B" class materials shall be protected in accordance with the provisions of 3.2. 19) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). 20) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 367. Section 22 - Structural Fire Protection on Board Seagoing Ships C 22-27/48 8. Windows and side scuttles 8.1 All windows and sidescuttles in bulkheads within accommodation and service spaces and control stations other than those to which the provisions of 6.7 and 7.4 apply, shall be so constructed as to preserve the integrity requirements of the type of bulkheads in which they are fitted. 8.2 NotwithstandingtherequirementsoftheTables 22.3and22.4,allwindowsandsidescuttlesinbulkheadsseparating accommodationandservicespacesandcontrolstationsfromweathershallbeconstructedwithframesofsteelorothersuitable material. The glass shall be retained by a metal glazing bead or angle. 8.3 Windows facing life-saving appliances, embarkation and muster areas, external stairs and open decks used for escaperoutes,andwindowssituatedbelowliferaftandescapeslideembarkationareasshallhavethefireintegrityasrequired intheTables22.1and22.2.Whereautomaticdedicatedsprinklerheadsareprovidedforwindows(seealsoRulesforMachinery Installations,VolumeIII, Section.12), An0 windows may be accepted as equivalent. Windows located in the ship's sidebelow the lifeboat embarkation areas shall have the fire integrity at least equal to "A-0" class. 9. Ventilation systems 9.1 Ventilation ducts shall be of non-combustible material. Short ducts, however, not generally exceeding 2 m in length and with a cross-section not exceeding 0,02 m2 need not be non-combustible, subject to the following conditions: 9.1.1 These ducts shall be of a material having low flame spread characteristics21) which is type approved; 9.1.2 They may only be used at the end of the ventilation device; 9.1.3 They shall not be situated less than 600 mm, measured along the duct, from an opening in an "A" or "B" class division including continuous "B" class ceilings. 9.2 Where a thin plated duct with a free cross-sectional area equal to or less than 0,02 m² pass through "A" class bulkheads or decks, the opening shall be lined with a steel sheet sleeve having a thickness of at least 3 mm and a length of at least 200 mm, divided preferably into 100 mm on each side of the bulkhead or, in the case of the deck, wholly laid on the lower side of the decks pierced. Where ventilation ducts with a free cross-sectional area exceeding 0,02 m² pass through "A" class bulkheads or decks, the opening shall be lined with a steel sheet sleeve. However, where such ducts are of steel construction and pass through a deck or bulkhead, the ducts and sleeves shall comply with the following: 9.2.1 Thesleevesshallhaveathicknessofatleast3mmandalengthofatleast900mm.Whenpassingthroughbulkheads, this length shall be divided preferably into 450 mm on each side of the bulkhead. These ducts, or sleeves lining such ducts, shall beprovidedwithfireinsulation.Theinsulationshallhaveatleastthe same fire integrity as the bulkhead or deck through which the duct passes. 9.2.2 Ducts with a free cross-sectional area exceeding 0,075 m2 shall be fitted with fire dampers in addition to the requirements of 9.2.1. The fire damper shall operate automatically but shall also be capable of being closed manually from both sides of the bulkhead or deck. The damper shall be provided with an indicator which shows whether the damper isopenorclosed.Firedampersarenotrequired,however,whereductspassthroughspaces surroundedby"A"classdivision, without serving those spaces, provided those ducts have the same fire integrity as the divisions which they pierce. Thefiredampersshouldbeeasilyaccessible.Wheretheyareplacedbehindceilingsandlinings,theselattershouldbeprovided with an inspection door on which a plate reporting the identification number of the fire damper. Such plate and identification number should be placed also on any remote control required. 9.2.3 The following arrangement shall be of an approved type 22) . 9.2.3.1 Fire dampers, including relevant means of operation 9.2.3.2 Ductpenetrationsthrough"A"classdivisions.Wheresteelsleevesaredirectlyjoinedtoventilationducts by means of riveted or screwed flanges or by welding, the test is not required. 9.3 The main inlets and outlets of all ventilation systems shall be capable of being closed from outside the respective 21) Reference is made to the Fire Test Procedure Code, Annex 1, Part 5, adopted by IMO by Resolution MSC 61(67). 22) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 368. C Section 22 - Structural Fire Protection on Board Seagoing Ships22-28/48 spaces in the event of a fire. 9.4 Where they pass through accommodation spaces or spaces containing combustible materials, the exhaust ducts from galley ranges shall be constructed of insulated "A" class divisions. Each exhaust duct shall be fitted with: 9.4.1 A grease trap readily removable for cleaning; 9.4.2 A fire damper located in the lower end of the duct; 9.4.3 Arrangements, operable from within the galley, for shutting off the exhaust fan; and 9.4.4 Fixedmeansforextinguishingafirewithintheduct(seeRulesforMachineryInstallations,VolumeIII,Section.12). 9.5 Such measures as are practicable shall be taken in respect of control stations outside machinery spaces in order to ensure that ventilation, visibility and freedom from smoke are maintained, so that in the event of fire the machinery and equipment contained therein may be supervised and continue to function effectively. Alternative and separate means of air supply shall be provided; air inlets of the two sources of supply shall be so disposed that the risk of both inlets drawing in smoke simultaneously is minimized. Such requirements need not apply to control stations situated on, and opening on to, an open deck. 9.6 TheventilationsystemsformachineryspacesofcategoryA, vehiclespaces,ro-rospaces,galleys,special category spacesandcargospacesshall, ingeneral, be separated from each other and from theventilationsystemservingotherspaces. Except, that the galley ventilation systems need not be completely separated, but may be served by separate ducts from a ventilation unit serving other spaces. In any case, an automatic fire damper shall be fitted in the galley ventilation duct near the ventilation unit. 9.7 Ducts provided for the ventilation of machinery spaces of category A, galleys, vehicle spaces, ro-ro cargo spaces or special category spaces shall not pass through accommodation spaces, service spaces or control stations unless the ducts are either complying with 9.7.1 or 9.7.2: 9.7.1 Constructed of steel having a thickness of at least 3 mm and 5 mm for ducts the widths or diameters of which are up to and including 300 mm and 760 mm and over respectively and, in the case of such ducts, the widths or diameters of which are between 300 mm and 760 mm having a thickness to be obtained by interpolation; suitably supported and stiffened; fitted with automatic fire dampers close to the boundaries penetrated; and insulated to "A-60" standard from the machinery spaces, galleys, vehicle spaces, ro-ro cargo spaces or special category spaces to a point at least 5 m beyond each fire damper; or 9.7.2 Constructed of steel suitable supported and stiffened in accordance with 9.7.1 and insulated to "A-60" standard throughout the accommodation spaces, service spaces or control stations; except that penetrations of main zone divisions shall also comply with the requirements of 9.11. 9.8 Ducts provided for the ventilation to accommodation spaces, service spaces or control stations shall not pass through machinery spaces ofcategory A, galleys, vehicle spaces, ro-ro cargo spaces or special category spaces unless either complying with 9.8.1 or 9.8.2: 9.8.1 The ducts where they pass through a machinery space of category A, galley, vehicle space, ro-ro cargo space or special category space are constructed of steel, suitable supported and stiffened in accordance with 9.7.1; and automatic fire dampers are fitted close to the boundaries penetrated; and integrityofthemachineryspace,galley,vehiclespace,ro-rocargospace or special category space boundaries is maintained at the penetrations; or 9.8.2 The ducts where they pass through a machinery space of category A, galley, vehicle space, ro-ro cargo space or special category space are constructed of steel, suitable supported and stiffened in accordance with 9.7.1 and are insulated to "A-60" standard within the machinery space, galley, vehicle space, ro-ro cargo space or special category space; except that penetrations of main zone division shall also comply with the requirements of 9.11. BKI - Rules for Hull - 2014
- 369. Section 22 - Structural Fire Protection on Board Seagoing Ships C 22-29/48 9.9 Ventilation ducts with a free cross-sectional area exceeding 0,02 m2 passing through "B" class bulkheads shall be lined with steel sheet sleeves of 900 mm in length divided preferably into 450 mm on each side of the bulkheads unless the duct is of steel for this length. 9.10 Powerventilationofaccommodationspaces,servicespaces, cargo spaces, control stations and machinery spaces shall be capable of being stopped from an easily accessible position outside the space being served. This position should not be readily cut off in the event of a fire in the spaces served. The means provided for stopping the power ventilation of the machinery spaces shall be entirely separate from the means provided for stopping ventilation of other spaces. 9.11 Where in a passenger ship it is necessary that a ventilation duct passes through a main vertical zone division, a fail-safe automatic closing fire damper shall be fitted adjacent to the division. The damper shall also be capable of being manually closed from each side of the division. The operating position shall be readily accessible and be marked in red light-reflecting colour. The duct between the division and the damper shall be of steel or other equivalent material and, if necessary, insulated to comply with the requirements of 6.1. The damper shall be fitted on at least one side of the division with a visible indicator showing whether the damper is in the open position. 10. Restriction of combustible materials 10.1 Except in cargo spaces, mail rooms, baggage rooms, saunas23) or refrigerated compartments of service spaces, all linings, grounds, draughts stops, ceilings and insulations shall be of non-combustible materials. Partial bulkheads or decks used to subdivide a space for utility or artistic treatment shall also be of non-combustible material. Linings,ceilingsandpartialbulkheadsordecksusedtoscreenortoseparateadjacentcabinbalconiesshallbeofnon-combustible material. 10.2 Vapour barriers and adhesives used in conjunction with insulation, as well as insulation of pipe fittings, for cold service systems need not be non-combustible but they shall be kept to the minimum quantity practicable and their exposed surfaces shall have low flame spread characteristics 10.3 The following surfaces shall have low flame spread characteristics 24) : 10.3.1 Exposedsurfacesincorridorsandstairwayenclosures,andofbulkheads,wallandceilingliningsinallaccommodation and service spaces (except saunas) and control stations; 10.3.2 Concealed or inaccessible spaces in accommodation, service spaces and control stations. 10.3.3 Exposed surfaces of cabin balconies, except for natural hard wood decking systems. 10.4 The total volume of combustible facings, mouldings, decorations and veneers in any accommodation and service space shall not exceed a volume equivalent to 2,5 mm veneer on the combined area of the walls and ceilings. Furniture fixed tolinings,bulkheadsordecksneed notbeincludedinthecalculationofthetotalvolumeofcombustiblematerials.Thisapplies also to traditional wooden benches and wooden linings on bulkheads and ceilings in saunas In the case of ships fitted with anautomaticsprinklersystem,theabovevolumemayincludesomecombustiblematerialusedforerectionof"C"classdivisions. 10.5 Combustible materials used on surfaces and linings covered by the requirements of 10.3 shall have a calorific value25) not exceeding 45 MJ/m2 of the area for the thickness used. This does notapply to surfaces of furniture fixed to linings or bulkheads as well as to traditional wooden benches and wooden linings on bulkheads and ceilings in saunas. 10.6 Furniture in stairway enclosures shall be limite to seating. It shall be fixed, limited to six seats on each deck in each stairway enclosure, be of restricted fire risk, and shall not restrict the passenger escape route. Furnitureshallnotbepermittedinpassengerandcrewcorridorsformingescaperoutesincabinareas.Locker ofnon-combustible material, providing storage for safety equipment, may be permitted within these areas. Drinking water dispensers and ice cube machines may be permitted in corridors provided they are fixed and do not restrict the width of the escape route. This applies as well to decorative flower arrangements, statues or other objects d’art such as paintings and tapestries in corridors and stairways. 23) Insulation material in saunas shall be non-combustible. 24) Reference is made to the Fire Test Procedure Code, Annex 1, Part 5, adopted by IMO by Resolution MSC.61(67). 25) The gross calorific value measured in accordance with ISO Standard 1716 - "Building Materials - Determination of Calorific Potential", should be quoted. BKI - Rules for Hull - 2014
- 370. C Section 22 - Structural Fire Protection on Board Seagoing Ships22-30/48 10.7 Furniture and furnishings on cabin balconies shallcomplywiththe following, unless such balconies are protected by a fixed pressure water-spraying and fixed fire detection and fire alarm systems (see B.10.7). 10.8 Paints,varnishesandotherfinishesusedonexposedinteriorsurfaces,includingcabinbalconieswiththeexclusion of natural hard wood decking systems, shall not be capable of producing excessive quantities of smoke and toxic products 26) . 10.9 Primary deck coverings, if applied within accommodation and service spaces and control stations, or if applied on cabin balconies, shall be of approved material which will not readily ignite, or give rise to smoke or toxic or explosive hazards at elevated temperatures 27) . 10.10 Waste receptacles (see B.10.10). 11. Details of construction 11.1 In accommodation and service spaces, control stations, corridors and stairways: air spaces enclosed behind ceilings, panelling or linings shall be suitably divided by close fitting draught stops not more than 14 m apart; in the vertical direction, such enclosed air spaces, including those behind linings of stairways, trunks, etc shall be closed at each deck. 11.2 The construction of ceilings and bulkheads shall be such that it will be possible, without impairing the efficiency of the fire protection, for the fire patrols to detect any smoke originating in concealed and inaccessible spaces. 11.3 Non-load bearing partial bulkheads separating adjacent cabin balconies shall be capable of being opened by the crew from each side for the purpose of fighting fires. 11.4 The cargo holds and machinery spaces shall be capable of being effectively sealed such as to prevent the inlet of air. Doors leading to machinery spaces of group A are to be provided with self-closing devices and 2 securing devices. All other machinery spaces, which are protected by a gas fire extinguishing system, are to be equipped with self-closing doors. 11.5 Construction and arrangement of saunas. See B.11.6. 12. Means of escape 12.1 Unless expressly provided otherwise in this regulation, at least two widely separated and ready means of escape shall be provided from all spaces or group of spaces. Lifts shall not be considered as forming one of the required means of escape. 12.2 Doors in escape routes shall, in general, open in-way of the direction of escape, except that 12.2.1 individual cabin doors may open into the cabins in order to avoid injury to persons in the corridor when the door is opened, and 12.2.2 doors in vertical emergency escape trunks may open out of the trunk in order to permit the trunk to be used both for escape and access. 12.3 Stairways and ladders shall be arranged to provide readymeans of escape to the lifeboat and liferaft embarkation deck from all passenger and crew spaces and from spaces in which the crew is normally employed, other than machinery spaces. In particular, the following provisions shall be complied with : 12.3.1 Below the bulkhead deck, two means of escape, at least one of which shall be independent of watertight doors, shall be provided from each watertight compartment or similarly restricted space or group of spaces. 26) Reference is made to the Fire Test Procedure Code, Annex 1, Part 2, adopted by IMO by Resolution MSC 61(67). 27) Reference is made to the Fire Test Procedure Code, Annex 1, Part 6, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 371. Section 22 - Structural Fire Protection on Board Seagoing Ships C 22-31/48 Due regard being paid to the nature and location of spaces and to the number of persons who normally might be employed there, exceptions are possible, however, stairways shall not be less than 800 mm in clear width with handrails on both sides. 12.3.2 Above the bulkhead deck, there shall be at least two means of escape from each main vertical zone or similarly restricted space or group of spaces at least one of which shall give access to a stairway forming a vertical escape. 12.3.3 At least one of the means of escape required by paragraphs 12.3.1 and 12.3.2 shall consist of a readily accessible enclosed stairway, which shall provide continuous fire shelter from the level of its origin to the appropriate lifeboat and liferaft embarkation decks, or to the uppermost weather deck if the embarkation deck does not extend to the main vertical zonebeingconsidered.Inthelattercase,directaccesstotheembarkationdeckbywayofexternalopenstairwaysandpassageways shall be provided and shall have emergency lighting (see also Rules for Electrical Installations, Volume IV, Section 3 and 11)andslip-freesurfacesunderfoot. Boundaries facing external open stairways and passageways forming part of an escape route and boundaries in such a position that their failure during a fire would impede escape to the embarkation deck shall havefireintegrity,includinginsulationvalues,inaccordancewiththeTables22.3and22.4.Thewidths,numberandcontinuity of escapes shall be as follows: 12.3.3.1 Stairways shall not be less than 900 mm in clear width. Stairways shall be fitted with handrails on each side. The minimum clear width of stairways shall be increased by 10 mm for every one person provided for in excess of 90 persons. The maximum clear width between handrails where stairways are wider than 900 mm shall be 1800 mm. The total number of persons to be evacuated by such stairways shall be assumedtobe two thirds of the crew and the total number of passengers in the areas served by such stairways28) . 12.3.3.2 All stairways sized for more than 90 persons shall be aligned fore and aft. 12.3.3.3 Doorways and corridors and intermediate landings included inmeans of escape shall besizedinthesamemanner as stairways. 12.3.3.4 Stairways shall not exceed 3,5 m in vertical rise without the provision of a landing and shall not have an angle of inclination greater than 45E. 12.3.3.5 Landings at each deck level shall be not less than 2 m2 in area and shall increase by 1 m2 for every 10 persons provided for in excess of 20 persons but need not exceed 16 m2 , except for those landings servicing public spaces having direct access onto the stairway enclosure. 12.3.4 Stairways serving only a space and a balcony in that space shall not be considered as forming one of the means of escape. 12.3.5 A corridor, lobby, or part of a corridor from which there is only one route ofescape shall be prohibited. Dead–end corridorsusedinserviceareaswhicharenecessaryforthepracticalutilityoftheship,suchasfueloilstationsandathwartship supply corridors, shall be permitted, provided such dead-end corridors are separated from crew accommodation areas and are inaccessible from passenger accommodation areas. Also, a part of the corridor that has a depth not exceeding its width is considered a recess or local extension and is permitted. 12.3.6 In addition to the emergency lighting (see also Rules for Electrical Installations, Volume IV, Section 3 and 11) the means of escape including stairways and exits, shall be marked by lighting or photoluminescent strip indicators placed not more than 0,3 m above the deck at all points of the escape route including angles and intersections. The marking shall enable passengers to identify all the routes of escape and readily identify the escape exits. If electric illumination is used, it shall be supplied by the emergency source of power and it shall be so arranged that the failure of any single light or cut in a lighting strip, will not result in the marking being ineffective. Additionally, all escape route signs and fire equipment locationmarkingsshallbeofphotoluminescent material or marked by lighting. Suchlightingorphotoluminescentequipment shall be of an approved type29) . 12.3.7 Public Spaces spanning three or more decksandcontaincombustiblessuchasfurniture and enclosed spaces such as shops, offices and restaurants shall have at each level withinthe space two means of escape, one of which shall have direct access to an enclosed vertical means of escape as mentioned under 12.3.3. 12.4 Ifaradiotelegraphstationhasnodirectaccesstotheopendeck,twomeansofescapefromoraccesstosuchstation 28) Reference is made to the Fire Safety Systems Code, adopted by IMO by Resolution MSC 98 (73). 29) Reference is made to the Fire Safety Systems Code, adopted by IMO by Resolution MSC 98(73). BKI - Rules for Hull - 2014
- 372. C Section 22 - Structural Fire Protection on Board Seagoing Ships22-32/48 shall be provided, one of which may be a porthole or window of sufficient size or another means. 12.5 In special category spaces the number and disposition of the means of escape both below and above the bulkhead deck shall be satisfactory as mentioned under 12.3.1, .2 and .3. 12.6 Two means of escape shall be provided from each machinery space. In particular, the following provisions shall be complied with : 12.6.1 Where the space is below the bulkhead deck the two means of escape shall consist of either : 12.6.1.1 two sets of steel ladders as widely separated as possible, leading to doors in the upper part of the space similarly separated and from which access is provided to the appropriate life boat and liferaft embarkation decks. One of these ladders shall be located within a protected enclosure having fire integrity, including insulation values, in accordance with the Tables 22.3 and 22.4 for a category [4] space, from the lower part of the space to a safe position outside the space. Self-closing doors of the same fire integrity standards shall be fitted in the enclosure. The ladder shall be fixed in such a way that heat is not transferred into the enclosure through non-insulated fixing points. The protected enclosure shall have minimum internal dimensions of at least 800 mm × 800 mm, and shall have emergency lighting provisions. 12.6.1.2 oronesteelladderleadingtoadoorintheupperpartofthespacefromwhichaccess isprovidedtotheembarkation deck an additionally, in the lower part of the space and in a position well separated from the ladder referred to, a steel door capable of being operated from each side and which provides access to a safe escape route from the lower part of the space to the embarkation deck. 12.6.2 Where the space is above the bulkhead deck, two means of escape shall be as widely separated as possible and the doors leading from such means of escape shall be in a position from which access is provided to the appropriate lifeboat and liferaft embarkation decks. Where such escapes require the use of ladders these shall be of steel. 12.6.3 A ship of a gross tonnage less than 1000 may be dispensed with one of the means of escape, due regard being paid to the width and disposition of the upper part of the space; and a ship of a gross tonnage of 1000 and above, may be dispensed with one means of escape from any such space so long as either a door or a steel ladder provides a safe escape routetotheembarkationdeck,dueregardbeing paid to the nature and location of the space and wether persons are normally employed in that space. 12.6.4 In the steering gear room, a second means of escape shall be provided when the emergency steering position is located in that space unless there is direct access to the open deck. 12.6.5 Oneoftheescaperoutesfromthemachineryspaceswherethecrew is normally employed shallavoiddirectaccess to any special category space. 12.6.6 Two means of escape shall be provided from a machinery control room within a machinery space, at least one of which shall provide continuous fire shelter to a safe position outside the machinery space. 12.7 Additional requirements for ro-ro passenger ships See B.12.7. 13. Fixed fire detection and fire alarm systems and automatic sprinkler, fire detection and fire alarm systems In any ship there shall be installed throughout each separate zone, whether vertical or horizontal, in all accommodation and service spaces and, where it is considered necessary, in control stations, except spaces which afford no substantial fire risk (such as void spaces, sanitary spaces, etc.) either: 13.1 a fixed fire detection and fire alarm system (see also Rules for Machinery Installations, Volume III, Section 12); or 13.2 an automatic sprinkler, fire detection and fire alarm system and in addition a fixed fire detection and fire alarm systemsoinstalledandarrangedastoprovidesmokedetectionincorridors,stairwaysandescaperouteswithinaccommodation spaces. 14. Protection of vehicle, special category and ro-ro spaces 14.1 The subdivision of such spaces in main vertical zones would defeat their intended purpose. Therefore equivalent protection shall be obtained in such spaces on the basis of a horizontal zone concept. A horizontal zone may include special BKI - Rules for Hull - 2014
- 373. Section 22 - Structural Fire Protection on Board Seagoing Ships C 22-33/48 category and ro-ro spaces on more than one deck provided that the total overall clear height for vehicles does not exceed 10 m, whereas the total overall clear height is the sum of distances between deck and web frames of the decks forming the horizontal zone. 14.2 Structural protection The boundary bulkheads and decks of special category spaces shall be insulated as required for category [11] spaces in Tables 22.3 and 22.4, whereas the boundary bulkheads and decks of closed and open ro-ro spaces shall have fire integrity as required for category [8] spaces in Tables 22.3 and 22.4. Indicators shall be provided on the navigating bridge which shall indicate when any fire door leading to or from the special category space is closed. 14.3 Fixed fire-extinguishing system 14.3.1 Vehicle spaces and ro-ro spaces which are not special category spaces and are capable of being sealed from a location outside of the cargo spaces shall be fitted with a fixed gas fire-extinguishing system of an approved type (see also Rules for Machinery Installations, Volume.III, Section 12). 14.3.2 Ro-roandvehiclespacesnotcapableofbeingsealedandspecialcategoryspacesshallbefittedwithafixed pressure water spraying system for manual operation of an approved type (see also Rules for Machinery Installations, Volume III, Section 12). 14.4 Ventilation system There shall be provided an effective power ventilation system for the special category spaces sufficient to give at least 10 air changes per hour and for closed ro-ro and vehicle spaces sufficient to give at least 6 air changes per hour. Beyond this, ahigher air exchangerateisrequiredduringtheperiodofloadingandunloading.Thesystemforsuchspacesshallbeentirely separated from other ventilation systems and shall be operating at all times when vehicles are in such spaces. Ventilation ducts serving such spaces capable of being effectively sealed shall be separated for each such space. The system shall be capable of being controlled from a position outside such spaces. The ventilation shall be such as to prevent air stratification and the formation of air pockets. Means shall be provided to indicate on the navigating bridge any loss or reduction of the required ventilating capacity. Arrangements shall be provided to permit a rapid shut-down and effective closure of the ventilation system in case of fire, taking into account the weather and sea conditions. Ventilation ducts, including dampers, within a common horizontal zone shall be made of steel. Ducts passing through other horizontal zones or machinery spaces shall be "A-60" class steel ducts complying with 9.11. Permanent openings in the side plating, the ends or deckhead of the spaces shall be so situated that a fire in the cargo space does not endanger stowage areas and embarkation stations for survival craft and accommodation spaces, service spaces and control stations in superstructures and deckhouses above the cargo spaces. 14.5 Fire detection Thereshallbeprovidedafixedfiredetectionandfirealarmsystemofanapprovedtype(seealsoRulesforMachineryInstallations, Volume III, Section 12). A sample extraction smoke detection system of an approved type (see also Rules for Machinery Installations, Volume III, Section 12) may be accepted as equivalent, except for open ro-ro spaces, open vehicle spaces and special category spaces. An efficient fire patrol system shall be maintained in special category spaces. In case of a continuous fire watch at all times during the voyage, a fixed fire detection and alarm system is not required therein. 15. Special arrangements in machinery spaces of category A 15.1 The number of skylights, doors, ventilators, openings in funnels to permit exhaust ventilation and other openings to machinery spaces shall be reduced to a minimum consistent with the needs of ventilation and the proper and safe working of the ship. 15.2 Skylights shall be of steel and shall not contain glass panels. Suitable arrangements shall be made to permit the release of smoke in the event of fire, from the space to be protected. The normal ventilation systems may be acceptable for this purpose. 15.3 Means of control shall be provided for permitting the release of smoke and such controls shall be located outside the space concernedsothat, in the event of fire, they will not becut off from the space they serve. The controlsshallbesituated BKI - Rules for Hull - 2014
- 374. C, D Section 22 - Structural Fire Protection on Board Seagoing Ships22-34/48 at one control position or grouped in as few positions as possible. Such positions shall have safe access from the open deck. 15.4 Such doors other than power-operated watertight doors shall be arranged so that positive closure is assured in case of fire in the space, by power-operated closing arrangements or by the provision of self-closing doors capable of closing against an inclination of 3,5E opposing closure and having a fail-safe hook-back facility, provided with a remotely operatedreleasedevice.Doorsforemergencyescapetrunksneednotbefittedwithafail-safehold-backfacilityandaremotely operated release device. 15.5 Means of control shall be provided for closing power-operated doors or actuating release mechanism on doors other than power-operated watertight doors. The control shall be located outside the space concerned, where they will not be cut off in the event of fire in the space it serves. The means of control shall be situated at one control position or grouped in as few positions as possible having direct access and safe access from the open deck. 15.6 Windows shall not be fitted in machinery space boundaries. This does not preclude the use of glass in control rooms within the machinery spaces. 15.7 The floor plating of normal passageways shall be made of steel. 16. Special requirements for ships carrying dangerous goods 16.1 Ventilation Adequate power ventilation shall be provided in enclosed cargo spaces. The arrangement shall be such as to provide for at least six air changes per hour in the cargo space based on an empty cargo space and for removal of vapours from the upper or lower parts of the cargo space, as appropriate. The fans shall be such as to avoid the possibility of ignition of flammable gas air mixtures. Suitable wire mesh guard shall be fitted over inlet and outlet ventilation openings. 16.2 Insulation of machinery space boundaries BulkheadsformingboundariesbetweencargospacesandmachineryspacesofcategoryAshallbeinsulatedto"A-60"standard, unless the dangerous goods are stowed at least 3 m horizontally away from such bulkheads. Other boundaries between such spaces shall be insulated to "A-60" standard. 16.3 Miscellaneous items The kind and extent of the fire extinguishing equipment are defined in Rules for Machinery Installations, Volume.III, Section 12. Electrical apparatus and cablings are to meet the requirements of Rules for Electrical Installations, Volume.IV, Section 14. D. Regulations on Fire Protection for Cargo Ships of 500 GT and over 1. Materials 1.1 The hull, decks, structural bulkheads, superstructures and deckhouses are to be of steel except where in special cases the use of other suitable material may be approved, having in mind the risk of fire. 1.2 Components made from aluminium alloys require special treatment, with regard to the mechanical properties of the material in case of temperature increase. In principle, the following is to be observed : 1.2.1 The insulation of "A" or "B" class divisions shall be such that the temperature of the structural core does not rise more than 200EC above the ambient temperature at anytime during the applicable fire exposure to the standard fire test. 1.2.2 Special attention shall be given to the insulation of aluminium alloy components of columns, stanchions and other structural members required to support lifeboat and liferaft stowage, launching and embarkation areas, and "A" and "B" class divisions to ensure: thatfor such members supportinglifeboatandliferaftareas and"A"class divisions, the temperature riselimitationspecified in 1.2.1 shall apply at the end of one hour; and BKI - Rules for Hull - 2014
- 375. Section 22 - Structural Fire Protection on Board Seagoing Ships D 22-35/48 that for such members required to support "B" class divisions, the temperature rise limitation specified in 1.2.1 shall apply at the end of half an hour. 1.2.3 Crowns and casings of machinery spaces of category A shall be of steel construction and be insulated as required by Table 22.5 as appropriate. Openings therein, if any, shall be suitably arranged and protected to prevent the spread of fire. 2. Accommodation and service spaces 2.1 One of the following methods of protection shall be adopted in accommodation and service areas: 2.1.1 Method IC Theconstructionofallinternaldivisionalbulkheadingofnon-combustible"B"or"C" class divisions generally without the installation of an automatic sprinkler, fire detection and fire alarm system in the accommodation and service spaces, except as required by 10.1; or 2.1.2 Method IIC The fitting of an automatic sprinkler, fire detection and fire alarm system, as required by 10.2 for the detection and extinction of fire in all spaces in which fire might be expected to originate, generally with no restriction on the type of internal divisional bulkheading; or 2.1.3 Method IIIC The fitting of a fixed fire detection and fire alarm system, as required by 10.3, in all spaces in which a fire might be expected to originate, generally with no restriction on the type of internal divisional bulkheading, except that in no case shall the area of any accommodation space or spaces bounded by an "A" or "B" class division exceed 50 m2 . Consideration may be given to increasing this area for public spaces. 2.2 Therequirementsfortheuseofnon-combustiblematerialsinconstructionandinsulationoftheboundarybulkheads of machinery spaces, control stations, service spaces, etc., and the protection of stairway enclosures and corridors will be common to all three methods. 3. Bulkheads within the accommodation and service spaces 3.1 Allbulkheadsrequiredtobe"B"class divisions shall extend from deck todeckandtotheshellorotherboundaries, unlesscontinuous"B"classceilingorliningsarefittedonbothsides ofthebulkheadinwhichcasethebulkheadmayterminate at the continuous ceiling or lining. 3.2 Method IC All bulkheads not required by this or other requirements of this Section to be "A" or "B" class divisions, shall be of at least "C" class construction. 3.3 Method IIC There shall be no restriction on the construction of bulkheads not required by this or other requirements of this Section to be "A" or "B" class divisions except in individual cases where "C" class bulkheads are required in accordance with Table 22.5. 3.4 Method IIIC There shall be no restriction on the construction of bulkheads not required by this Section to be "A" or "B" class divisions except that area of any accommodation space or space bounded by a continuous "A" or "B" class division shall in no case exceed50m2 exceptinindividualcaseswhere"C"classbulkheadsarerequiredinaccordance withTable 22.5. consideration may be given to increasing this area for public spaces. 4. Fire integrity of bulkheads and decks 4.1 In addition to complying with the specificprovisionsforfireintegrityofbulkheadsand decks mentioned elsewhere in this Section, the minimum fire integrity of bulkheads and decks shall be as prescribed in Tables 22.5 and 22.6 4.2 On ships intended for the carriage of dangerous goods the bulkheads forming boundaries between cargo spaces and machinery spaces of category A shall be insulated to "A-60" standard, unless the dangerous goods are stowed at least 3 m horizontally away from such bulkheads. Other boundaries between such spaces shall be insulated to "A-60" standard. 4.3 Continuous "B" class ceiling or linings, in association with the relevant decks or bulkheads may be accepted as contributing, wholly or in part, to the required insulation and integrity of a division. BKI - Rules for Hull - 2014
- 376. D Section 22 - Structural Fire Protection on Board Seagoing Ships22-36/48 4.4 External boundaries which are required in 1.1 to be of steel or other equivalent material may be pierced for the fittingofwindowsandsidescutlesprovidedthatthereisnorequirementforsuchboundariestohave"A"classintegrityelsewhere intheserequirements.Similarly,insuchboundarieswhicharenotrequiredtohave"A"classintegrity,doorsmaybeofmaterials to meet the requirements of their application. 4.5 The following requirements shall govern application of the Tables: Tables 22.5 and 22.6 shall apply respectively to the bulkheads and decks separating adjacent spaces. 4.6 For determining the appropriate fire integrity standards to be applied to divisions between adjacent spaces, such spaces are classified according to their fire risk as shown in the following categories [1] to [11]. Where the contents and use of a space are such that there is a doubt as to its classification for the purpose of this regulation, or where it is possible to assign two or more classifications to a space, it shall be treated as a space within the relevant category having the most stringent boundary requirements. Smaller, enclosed room within a space that have less than 30 % communicating openings to that space are to be considered separate spaces. The fire integrity of the boundary bulkheads of such smaller rooms shall beasprescribedinTables22.5and22.6.Thetitleofeachcategoryisintendedtobetypicalratherthanrestrictive.Thenumber in parentheses preceding each category refers to the applicable column or row number in the tables. Table 22.5 Fire integrity of bulkheads separating adjacent spaces Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] Control stations [1] A-05 A-0 A-60 A-0 A-15 A-60 A-15 A-60 A-60 10 A-60 Corridors [2] C B-0 B-0 A-03 B-0 A-60 A-0 A-0 A-0 10 A-30 Accommodation spaces [3] C1,2 B-0 A-03 B-0 A-60 A-0 A-0 A-0 10 A-30 Stairways [4] B-0 A-03 B-0 A-03 A-60 A-0 A-0 A-0 10 10 A-30 Service spaces (low risk) [5] C A-60 A-0 A-0 A-0 10 A-0 Machinery spaces of category A [6] 10 A-0 A-07 A-60 10 A-606 Other machinery spaces [7] A-04 A-0 A-0 10 A-0 Cargo spaces [8] 10 A-0 10 A-0 Service spaces (high risk) [9] A-04 10 A-30 Open decks [10] - A-0 Ro-ro and vehicle spaces [11] 10,8 Notes to be applied to Tables 22.5 and 22.6, as appropriate 1. No special requirements are imposed upon bulkheads in methods IIC and IIIC fire protection. 2. In case of method IIC "B" class bulkheads of "B-0" rating shall be provided between spaces or groups of spaces of 50 m2 and over in area. 3. For clarification as to which applies, see 3 and 5. 4. Where spaces are of the same numerical category and superscript 4 appears, a bulkhead or deck of the rating shown in the Tables in only required when the adjacent spaces are for a different purpose, e.g. in category [9]. A galley next to a galley does not require a bulkhead but a galley next to a paint room requires an "A-0" bulkhead. 5. Bulkheads separating the wheelhouse, chartroom and radio room from each other may be "B-0" rating. 6. "A-0" rating may be used if no dangerous goods are intended to be carried or if such goods are stowed not less than 3 m horizontally from such bulkhead. 7. For cargo spaces in which dangerous goods are intended to be carried 4.2 applies. 8. Bulkheads and decks separating ro-ro cargo spaces shall be capable of being closed reasonably gastight and such divisions shall have "A" class integrity in so far as is reasonable and practicable. 9. Fire insulation need not be fitted if the machinery spaces in category [7], has little or no fire risk. 10. Where a 10 appears in the Tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class standard. BKI - Rules for Hull - 2014
- 377. Section 22 - Structural Fire Protection on Board Seagoing Ships D 22-37/48 Table 22.6 Fire integrity of decks separating adjacent spaces Space above [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] Space below Control stations [1] A-0 A-0 A-0 A-0 A-0 A-60 A-0 A-0 A-0 10 A-60 Corridors [2] A-0 10 10 A-0 10 A-60 A-0 A-0 A-0 10 A-30 Accommodation spaces [3] A-60 A-0 10 A-0 10 A-60 A-0 A-0 A-0 10 A-30 Stairways [4] A-0 A-0 A-0 10 A-0 A-60 A-0 A-0 A-0 10 A-30 Service spaces (low risk) [5] A-15 A-0 A-0 A-0 10 A-60 A-0 A-0 A-0 10 A-0 Machinery spaces of category A [6] A-60 A-60 A-60 A-60 A-60 10 A-609 A-30 A-60 10 A-60 Other machinery spaces [7] A-15 A-0 A-0 A-0 A-0 A-0 10 A-0 A-0 10 A-0 Cargo spaces [8] A-60 A-0 A-0 A-0 A-0 A-0 A-0 10 A-0 10 A-0 Service spaces (high risk) [9] A-60 A-0 A-0 A-0 A-0 A-60 A-0 A-0 A-04 10 A-30 Open decks [10] 10 10 10 10 10 10 10 10 10 - 10 Ro-ro and vehicle spaces [11] A-60 A-30 A-30 A-30 A-0 A-60 A-0 A-0 A-30 10 10, 8 See notes under Table 22.5 [1] Control stations Spaces containing emergency sources of power and lighting. Wheelhouse and chart-room.Spacescontainingtheship's radio equipment. Fire control stations. Control room for propulsion machinery when located outside the machinery space. Spaces containing centralized fire alarm equipment. [2] Corridors Corridors and lobbies. [3] Accommodation spaces Spaces used for public spaces, lavatories, cabins, offices, hospitals, cinemas, games and hobby rooms, barber ships, pantries containing no cooking appliances and similar spaces. [4] Stairways Interior stairways, lifts, totally enclosed emergency escape trunks and escalators (other than those wholly contained within the machinery spaces) and enclosures thereto. In this connection, a stairway which is enclosed only at one level shall be regarded as part of the space from which it is not separated by a fire door. [5] Service spaces (low risk) Lockers and store-rooms not having provision for the storage of flammable liquids and having areas less than 4 m2 and drying rooms and laundries. [6] Machinery spaces of category A Spaces and trunks to such spaces which contain: internal combustible machinery used for main propulsion; or internalcombustiblemachineryusedforpurposesotherthanmainpropulsionwhere suchmachineryhasintheaggregate a total power output of not less than 375 kW; or any oil-fired boiler or oil fuel unit. [7] Other machinery spaces Spaces, other than machinery spaces of category A, containing propulsion machinery, boilers, oil fuel units, steam and internal combustion engines, generators and major electrical machinery, oil filling stations, refrigerating, stabilizing, ventilation and air conditioning machinery, and similar spaces,and trunks to such spaces. Electrical equipment rooms (auto-telephone exchange, air-conditioning duct spaces). BKI - Rules for Hull - 2014
- 378. D Section 22 - Structural Fire Protection on Board Seagoing Ships22-38/48 [8] Cargo spaces All spaces used for cargo (including cargo oil tanks) and trunkways and hatchways to such spaces. [9] Service spaces (high risk) Galleys, pantries containing cookingappliances, saunas, paint and lamp rooms, lockers and store-rooms having areas of4m2 ormore,spacesforthestorageofflammableliquids,andworkshopsotherthanthoseformingpartofthemachinery spaces. [10] Open decks Open deck spaces and enclosed promenades having no fire risk. Enclosed promenades shall have no significant fire risk,meaningthatfurnishingshouldberestrictedtodeckfurniture.Inaddition,suchspacesshallbenaturallyventilated by permanent openings. Air spaces (the space outside superstructures and deckhouses). [11] Ro-ro and vehicle spaces 5. Protection of stairways and lift trunks in accommodation spaces, service spaces and control stations 5.1 Stairwayswhichpenetrateonlyasingledeck shall be protected at least at one level by atleast"B-0"classdivisions and self-closing doors. Lifts which penetrate only a single deck shall be surrounded by "A-0"class divisions with steel doors at both levels. Stairways and lift trunks which penetrate more than a single deck shall be surrounded by at least "A-0" class divisions and be protected by self-closing doors at all levels. 5.2 On ships having accommodation for 12 persons or less, where stairways penetrate more than a single deck and where there are at least two escape routes direct to the open deck at every accommodation level, consideration may be given reducing the "A-0" requirements of 5.1 to "B-0". 5.3 All stairways shall be of steel frame construction or of other equivalent material. 6. Openings in fire resisting divisions 6.1 Where "A" or "B" class division are penetrated for the passage of electric cables, pipes, trunks, ducts, etc. or forgirders,beamsorotherstructuralmembers,arrangementsshallbe made to ensure thatthe fire resistanceisnotimpaired. 6.2 Except for hatches between cargo, special category, store, and baggage spaces, and between such spaces and theweatherdecks,allopeningsshallbeprovidedwithpermanentlyattachedmeansofclosingwhichshallbeatleastaseffective for resisting fires as the divisions in which they are fitted 30) . 6.3 The fire resistance of doors shall be equivalent to that of the division in which they are fitted. Doors and door frames in"A"class divisions shallbe constructedofsteel. Doors in"B"class divisions shallbenon-combustible. Doors fitted in boundary bulkheads of machinery spaces of category A shall be reasonably gastight and self-closing. In ships constructed according to method IC the use of combustible materials in doors separating cabins from individual interior sanitary accommodation such as showers may be permitted. 6.4 Doorsrequiredtobe self-closing shallnotbefittedwithhold-backhooks.However,hold-backarrangementsfitted with remote release devices of the fail-safe type may be utilized. 6.5 In corridor bulkheads ventilation openings may be permitted only in and under class B-doors of cabins and public spaces. Ventilation openings are also permitted in B-doors leading to lavatories, offices, pantries, lockers and store rooms. Except as permitted below, the openings shall be provided only in the lower half of a door. Where such opening is in or under adoorthetotalnetareaofanysuchopeningoropeningsshallnotexceed0,05m².Alternatively,anon-combustibleairbalance duct routed between the cabin and the corridor, and located below the sanitary unit is permitted where the cross-sectional area of the duct does not exceed 0,05 m². Ventilation openings, except those under the door, shall be fitted with a grille made of non-combustible material. 6.6 Watertight doors need not be insulated. 30) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 379. Section 22 - Structural Fire Protection on Board Seagoing Ships D 22-39/48 7. Ventilation systems 7.1 Ventilation ducts shall be of non-combustible material. Short ducts, however, not generally exceeding 2 m in length and with a cross-section not exceeding 0,02 m2 need not be non-combustible, subject to the following conditions: 7.1.1 these ducts shall be of a material having low flame spread characteristics which is type approved 31) . 7.1.2 they may only be used at the end of the ventilation device; 7.1.3 theyshallnotbesituatedlessthan600mm,measuredalongtheduct,fromanopeninginan"A"or"B"classdivision including continuous "B" class ceilings. 7.2 Where a thin plated duct with a free cross-sectional area equal to, or less than, 0,02 m² passes through "A" class bulkheads or decks, the opening shall be lined with a steel sheet sleeve having a thickness of at least 3 mm and a length of at least 200 mm, divided preferably into 100 mm on each side of the bulkhead or, in the case of the deck, wholly laid on the lower side of the decks pierced. Where ventilation ducts with a free cross-sectional area exceeding 0,02, m² pass through "A" class bulkheads or decks, the opening shall be lined with a steel sheet sleeve. However, where such ducts are of steel construction and pass through a deck or bulkhead, the ducts and sleeves shall comply with the following: 7.2.1 The sleeves shall have a thickness of at least 3 mm and a length at least 900 mm. When passing through bulkheads, this length shall be divided preferably into 450 mm on each side of the bulkhead. These ducts, or sleeves lining such ducts, shallbeprovided withfire insulation. The insulationshallhave atleastthesamefireintegrityasthebulkheadordeckthrough which the duct passes. 7.2.2 Ducts with a free cross-sectional area exceeding 0,075 m2 shall be fitted with the fire dampers in addition to the requirements of 7.2.1. The fire dampers shall also be capable of being closed manually from both sides of the bulkhead or deck. The damper shall be provided with an indicator which shows whether the damper is open or closed. Fire dampers are not required, however, where ducts pass through spaces surroundedby"A"classdivisions,withoutservingthosespaces, provided those ducts have the same fire integrity as the divisions which they pierce. 7.2.3 The following arrangement shall be of an approved type 32) . 7.2.3.1 fire dampers, including relevant means of operation 7.2.3.2 ductpenetrationsthrough"A"classdivisions.Wheresteelsleeves are directly joined to ventilation ducts by means of riveted or screwed flanges or by welding, the test is not required. 7.3 The main inlets and outlets of all ventilation systems shall be capable of being closed from outside the respective spaces in the event of a fire. 7.4 Where they pass through accommodation spaces or spaces containing combustible materials, the exhaust ducts from galley ranges shall be constructed of insulated "A" class divisions. Each exhaust duct shall be fitted with: 7.4.1 a grease trap readily removable for cleaning; 7.4.2 a fire damper located in the lower end of the duct; 7.4.3 arrangements, operable from within the galley, for shutting off the exhaust fan; and 7.4.4 fixedmeansforextinguishingafirewithin the duct(see Rules for Machinery Installations,VolumeIII,Section.12). 7.5 Such measures as are practicable shall be taken in respect of control stations outside machinery spaces in order to ensure that ventilation, visibility and freedom from smoke are maintained, so that in the event of fire the machinery and equipment contained therein may be supervised and continue to function effectively. Alternative and separate means of air supply shall be provided; air inlets of two sources of supply shall be so disposed that the risk of both inlets drawing in smoke simultaneously is minimized. Such requirements need not apply to control stations situated on, and opening on to, an open deck. 31) Reference is made to the Fire Test Procedure Code, Annex 1, Part 5, adopted by IMO by Resolution MSC 61(67). 32) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 380. D Section 22 - Structural Fire Protection on Board Seagoing Ships22-40/48 7.6 The ventilation system for machinery spaces of category A, vehicle spaces, ro-ro spaces, galleys, special category spacesandcargospacesshall,ingeneral,beseparatedfromeachotherandfromtheventilationsystemsservingotherspaces. Except that galley ventilation on cargo ships of less than 4000 gross tonnage need not be completely separated, but may be served by separate ducts from a ventilation unit serving other spaces. In any case, an automatic fire damper shall be fitted in the galley ventilation ducts near the ventilation unit. 7.7 Ducts provided for the ventilation of machinery spaces of category A, galleys, vehicle spaces, ro-ro cargo spaces or special category spaces shall not pass through accommodation spaces, service spaces or control stations unless the ducts are either: 7.7.1 constructed of steel having a thickness of at least 3 mm and 5 mm for ducts the widths or diameters of which are up to and including 300 mm and 760 mm and over respectively and, in the case of such ducts, the widths or diameters of which are between 300 mm and 760 mm having a thickness to be obtained by interpolation; suitably supported and stiffened; fitted with automatic fire dampers close to the boundaries penetrated; and insulated to "A-60" standard from the machinery spaces, galleys, vehicle spaces, ro-ro cargo spaces or special category spaces to a point at least 5 m beyond each fire damper; or 7.7.2 constructedofsteelsuitablesupportedandstiffenedandinsulatedto"A-60"standardthroughouttheaccommodation spaces, service spaces or control stations. 7.8 Ducts provided for the ventilation to accommodation spaces, service spaces or control stations shall not pass throughmachinery spacesof categoryA,galleys,vehiclespaces,ro-rocargospacesorspecialcategoryspacesunlesseither: 7.8.1 the ducts where they pass through a machinery space of category A, galley, vehicle space, ro-ro cargo space or special category space are constructed of steel, suitable supported and stiffened and automatic fire dampers are fitted close to the boundaries penetrated; and theintegrityofthemachineryspace,galley,vehiclespace,ro-rocargospaceorspecial categoryspaceboundariesismaintained at the penetrations; or 7.8.2 the ducts where they pass through a machinery space of category A, galley, vehicle space, ro-ro cargo space or special category space are constructed of steel, suitable supported and stiffened, and are insulated to "A-60" standard throughout the accommodation spaces, service spaces or control stations. 7.9 Ventilation ducts with a free cross-sectional area exceeding 0,02 m2 passing through "B" class bulkheads shall be lined with steel sheet sleeves of 900 mm in length divided preferably into 450 mm on each side of the bulkheads unless the duct is of steel for this length. 7.10 Power ventilationofaccommodationspaces,servicespaces,cargospaces,controlstationsand machinery spaces shall be capable of being stopped from an easily accessible position outside the space being served. This position should not be readily cut off in the event of a fire in the spaces served. The means provided for stopping the power ventilation of the machinery spaces shall be entirely separate from the means provided for stopping ventilation of other spaces. 8. Restricted use of combustible materials 8.1 Allexposedsurfacesincorridorsandstairwayenclosuresandsurfacesincluding groundsinconcealedorinaccessible spacesinaccommodationandservicespacesandcontrolstationsshallhavelowflame-spreadcharacteristics.Exposedsurfaces of ceilings in accommodation and service spaces (except saunas) and control stations shall have low flame-spread characteristics.33) . 8.2 Paints, varnishes and other finished used on exposed interior surfaces shall not offer an undue fire hazard and shall not be capable of producing excessive quantities of smoke 34) . 8.3 Primarydeckcoverings,ifapplied,inaccommodationandservicespacesandcontrolstationsshallbeofanapproved 33) Reference is made to the Fire Test Procedure Code, Annex 1, Part 5, adopted by IMO by Resolution MSC 61(67). 34) Reference is made to the Fire Test Procedure Code, Annex 1, Part 2, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 381. Section 22 - Structural Fire Protection on Board Seagoing Ships D 22-41/48 material which will not readily ignite, or give rise to toxic or explosive hazardous at elevated temperatures35) . 8.4 Waste receptacles (see B.10.10) 9. Details of construction 9.1 Method IC In accommodation and service spaces and control stations all linings, draught stops, ceilings and their associated grounds shall be of non-combustible materials. 9.2 Method IIC and IIIC Incorridorsandstairwayenclosuresservingaccommodationandservicespacesandcontrolstations,ceilings,linings,draught stops and their associated grounds shall be of non-combustible materials. 9.3 Methods IC, IIC and IIIC 9.3.1 Exceptincargospacesorrefrigeratedcompartmentsofservicespaces,insulatingmaterialsshallbenon-combustible. Vapour barriers and adhesives used in conjunction with insulation, as well as the insulation of pipe fittings, for cold service systems, need not be of non-combustible materials, but they shall be kept to the minimum quantity practicable and their exposed surfaces shall have low flame-spread characteristics. 9.3.2 Where non-combustible bulkheads, linings and ceilings are fitted in accommodation and service spaces they may have a combustible veneer with a calorific value36) not exceeding 45 MJ/m2 of the area for the thickness used. 9.3.3 The total volume of combustible facings, moulding, decorations and veneers in any accommodation and service space bounded by non-combustible bulkheads, ceilings and linings shall not exceed a volume equivalent to a 2,5.mm veneer on the combined area of the walls and ceilings. 9.3.4 Air spaces enclosed behind ceilings, panellings, or linings, shall be divided by close fitting draught stops spaced not more than 14 m apart. In the vertical direction, such air spaces, including those behind linings of stairways, trunks, etc., shall be closed at each deck. 10. Fixed fire detection and fire alarm systems, automatic sprinkler, fire detection and fire alarm systems 10.1 In ships in which method IC is adopted, a smoke detection system shall be so installed and arranged as to protect all corridors, stairways and escape routes within accommodation spaces. 10.2 In ships in which method IIC is adopted, an automatic sprinkler, fire detection and fire alarm system shall be so installed and arranged as to protect accommodationspaces, galleys, and other service spaces, except spaces which afford no substantial fire risk such as void spaces, sanitary spaces, etc. In addition, a fixed fire detection and fire alarm system shall be so arranged and installed as to provide smoke detection in all corridors, stairways and escape routes within accommodation spaces. 10.3 In ships in which method IIIC is adopted, a fixed fire detection and fire alarm system shall be so installed and arranged as to detect the presence of fire in all accommodation spaces and service spaces, except spaces which afford no substantial fire risk such as void spaces, sanitary spaces, etc. In addition, a fixed fire detection and fire alarm system shall besoarrangedandinstalledastoprovidesmokedetectioninallcorridors,stairwaysandescaperouteswithinaccommodation spaces. 11. Means of escape 11.1 Unless expressly provided otherwise in this regulation, at least two widely separated and ready means of escape shall be provided from all spaces and group of spaces. Lifts shall not be considered as forming one of the required means of escape. 35) Reference is made to the Fire Test Procedure Code, Annex 1, Part 6, adopted by IMO by Resolution MSC 61(67). 36) The gross calorific value measured in accordance with ISO Standard 1716 - "Building Materials - Determination of Calorific Potential", should be quoted. BKI - Rules for Hull - 2014
- 382. D Section 22 - Structural Fire Protection on Board Seagoing Ships22-42/48 11.2 Doors in escape routes shall, in general, open in-way of the direction of escape, except that 11.2.1 individual cabin doors may open into the cabins in order to avoid injury to persons in the corridor when the door is opened, and 11.2.2 doors in vertical emergency escape trunks may open out of the trunk in order to permit the trunk to be used both for escape and access. 11.3 Stairways and ladders shall be so arranged as to provide, from all accommodation spaces and from spaces in which the crew is normally employed, other than machinery spaces, ready means of escape to the open deck and thence to the lifeboats and liferafts. In particular the following general provisions shall be complied with : 11.3.1 At all levels of accommodation there shall be provided at least two widely separated means of escape from each restricted space or group of spaces. 11.3.2 Below the lowest open deck the main means of escape shall be a stairway and the second escape may be a trunk or stairway. 11.3.3 Above the lowest open deck the means of escape shall be stairways or doors to an open deck or a combination thereof. 11.4 Stairways and corridors used as means of escape shall be not less than 700 mm in clear width and shall have a handrail on one side. Stairways and corridors with a clear width of 1800 mm and above shall have handrails on both sides. The angle of inclination of stairways shall be, in general, 45°, but not greater than 50°, and in machinery spaces and small spaces not more than 60°. Doorways which give access to a stairway shall be of the same size as the stairway 37) . 11.5 Dispense may be given with one of the means of escape, due regard being paid to the nature and location of spaces and to the numbers of persons who normally might be quartered or employed there. 11.6 No dead-end corridors having a length of more than 7 m shall be accepted. A dead-end corridor is a corridor or part of a corridor from which there is only one escape route. 11.7 If a radiotelegraph station has no direct access to the open deck, two means of access to or egress from such stationshallbeprovided,oneofwhichmaybeaportholeorwindow of sufficient size or other means to provide an emergency escape. 11.8 At least two means shall be provided in ro-ro cargo spaces where the crew are normally employed. The escape routes shall provide safe escape to the lifeboat and liferaft embarkation decks and shall be located at the fore and aft ends of the space. 11.9 TwomeansofescapeshallbeprovidedfromeachmachineryspaceofcategoryA.Inparticular,oneofthefollowing provisions shall be complied with : 11.9.1 Two sets of steel ladders as widely separated as possible leading to doors in the upper part of the space similarly separatedandfromwhichaccessisprovidedtotheopendeck.Oneoftheseladdersshallbelocatedwithinaprotectedenclosure having fire integrity, including insulation values, in accordance with the Tables 22.5 and 22.6 for category [4] space from the lower part of the space to a safe position outside the space. Self-closing fire doors having the same fire integrity shall be fitted in the enclosure. The ladder shall be fixed in such a way that heat is not transferred into the enclosure through non- insulated fixing points. The enclosure shall have minimum internal dimensions of at least 800 mm × 800 mm, and shall have emergency lighting provisions; or 11.9.2 One steel ladder leading to a door in the upper part of the space from which access is provided to the open deck and additionally, in the lower part of the space and in a position well separated from the ladder referred to, a steel door capable of being operated from each side and which provides access to a safe escape route from the lower part of the space to the open deck. 11.9.3 For a ship of a gross tonnage less than 1000, dispense may be given with one of the means of escape due regard being paid to the dimension and disposition of the upper part of the space. 37) Reference is made to the Fire Safety Systems Code adopted by IMO by Resolution MSC 98(73). BKI - Rules for Hull - 2014
- 383. Section 22 - Structural Fire Protection on Board Seagoing Ships D 22-43/48 11.9.4 In the steering gear room, a second means of escape shall be provided when the emergency steering position is located in that space unless there is direct access to the open deck. 11.10 From machinery spaces other than those of category A; two escape routes shall be provided except that a single escaperoutemaybeacceptedforspacesthatareenteredonlyoccasionally,andforspaceswherethemaximumtraveldistance to the door is 5 m or less. 12. Miscellaneous items 12.1 The cargo holds and machinery spaces shall be capable of being effectively sealed such as to prevent the inlet of air. Doors fitted in boundary bulkheads of machinery spaces of category A shall be reasonably gastight and self-closing. 12.2 Construction and arrangement of saunas, see B.11.6 13. Protection of cargo spaces 13.1 Fire-extinguishing arrangements in cargo spaces Fire-extinguishing arrangements according to Rules for Machinery Installations, Volume III, Section 12 are to be provided for cargo spaces. 14. Protection of vehicle and ro-ro spaces 14.1 Fire detection Thereshallbeprovidedafixedfiredetectionandfirealarmsystemofanapprovedtype(seealsoRulesforMachineryInstallations, Volume III, Section 12). A sample extraction smoke detection system of an approved type (see also Rules for Machinery Installations, Volume.III, Section 12) may be accepted as equivalent, except for open ro-ro and vehicle spaces. 14.2 Fire-extinguishing arrangements 14.2.1 Vehicle spaces and ro-ro spaces which are capable of being sealed from a location outside of the cargo spaces shall be fitted with a fixed gas fire-extinguishing system of an approved type (see also Rules for Machinery Installations, Volume III, Section 12). 14.2.2 Ro-ro and vehicle spaces not capable of being sealed shall be fitted with a fixed pressure water spraying system for manual operation of an approved type (see also Rules for Machinery Installations, Volume III, Section 12). 14.3 Ventilation system Closed vehicle and ro-ro spaces shall be provided with an effective power ventilation system sufficient to give at least 6 air changes per hour. Beyond this, a higher air exchange rate may be required during the period of loading and unloading and/or depending on the electrical installation. The system for such cargo spaces shall be entirely separate from other ventilation systems and shall be operating at all times when vehicles are in such spaces. Ventilation ducts serving such cargo spaces capable of being effectively sealed shall be separated for each such space. The system shall be capable of being controlled from a position outside such spaces. The ventilation shall be such as to prevent air stratification and the formation of air pockets. Means shall be provided to indicate on the navigating bridge any loss of the required ventilating capacity. Arrangements shall be provided to permit a rapid shut-down and effective closure of the ventilation system in case of fire, taking into account the weather and sea conditions. Ventilation duct, including dampers, shall be made of steel. Permanent openings in the side plating, the ends or deckhead of the spaces shall be so situated that a fire in the cargo space does not endanger stowage areas and embarkation stations for survival craft and accommodation spaces, service spaces and control stations in superstructures and deckhouses above the cargo spaces. BKI - Rules for Hull - 2014
- 384. F Section 22 - Structural Fire Protection on Board Seagoing Ships22-44/48 15. Special requirements for ships carrying dangerous goods 15.1 Ventilation Adequate power ventilation shall be provided in enclosed cargo spaces. The arrangement shall be such as to provide for at least six air changes per hour in the cargo space based on an empty cargo space and for removal of vapours from the upper or lower parts of the cargo space, as appropriate. The fans shall be such as to avoid the possibility of ignition of flammable gas air mixtures. Suitable wire mesh guard shall be fitted over inlet and outlet ventilation openings. Natural ventilation shall be provided in enclosed cargo spaces intended for the carriage of solid dangerous goods in bulk, where there is no provision for mechanical ventilation. 15.2 Insulation of machinery space boundaries BulkheadsformingboundariesbetweencargospacesandmachineryspacesofcategoryAshallbeinsulatedto"A-60"standard, unless the dangerous goods are stowed at least 3 m horizontally away from such bulkheads. Other boundaries between such spaces shall be insulated to "A-60" standard. 15.3 Separation of spaces 15.3.1 In ships having ro-ro spaces, a separation shall be provided between a closed ro-ro space and an adjacent open ro-ro space. The separation shall be such as to minimize the passage of dangerous vapours and liquids between such spaces. Alternatively, such separation need not be provided if the ro-ro space is considered to be a closed cargo space over its entire length and shall fully comply with requirements of 14. 15.3.2 Inshipshavingro-rospaces,aseparationshallbeprovidedbetweenaclosedro-rospaceandtheadjacentweather deck.Theseparationshallbesuchastominimizethepassageofdangerousvapoursandliquidsbetweensuchspaces.Alternatively, a separation need not be provided if the closed ro-ro spaces are in accordance with those required for the dangerous goods carried on the adjacent weather deck. 15.4 Miscellaneous items The kind and extent of the fire extinguishing equipment are to meet the requirements of Rules for Machinery Installations, Volume III, Section 12. Electrical apparatus and cablings are to meet the requirements of Rules for Electrical Installations, Volume.IV, Section 17. E. Regulations on Fire Protection for Cargo Ships of less than 500 GT In general the requirements stated under D are to be observed for cargo ships of less than 500 GT. Deviations from the requirements of this subsection may be approved considering the ship's size and ship's type. F. Regulations on Fire Protection for Oil Tankers of 500 GT and over (These requirements are additional to those of D except as provided otherwise in 3 and 4). 1. Application 1.1 Unlessexpresslyprovidedotherwise,thisSectionshallapplytotankers carryingcrudeoilandpetroleumproducts having a flashpoint not exceeding 60EC (closed-cup test), as determined by an approved flashpoint apparatus, and a Reid vapour pressure which is below atmospheric pressure and other liquid products having a similar fire hazard. 1.2 Where liquid cargoes other than those referred to in 1.1 or liquefied gases which introduce additional fire hazard are intended to be carried the requirements for Ships Carrying Liquefied Gases in Bulk (Volume IX) and the requirements for Ships Carrying Dangerous Chemicals in Bulk (Volume X) are to be taken into account. 1.3 Tankers carrying petroleum products having a flashpoint exceeding 60EC (closed cup test) as determined by an approved flashpoint apparatus shall comply with the provisions of D. BKI - Rules for Hull - 2014
- 385. Section 22 - Structural Fire Protection on Board Seagoing Ships F 22-45/48 1.4 Chemical tankers and gas carriers shall comply with the requirements of this Section, unless other and additional safety precautions according the requirements for Ships Carrying Liquefied Gases inBulk(VolumeIX)andtherequirements for Ships Carrying Dangerous Chemicals in Bulk (Volume X) apply. 2. Construction 2.1 Exterior boundariesofsuperstructuresanddeckhousesenclosingaccommodationandincludinganyoverhanging decks which support such accommodation, shall be constructed of steel and insulated to "A-60" standard for the whole of the portions which face the cargo area and on the outward sides for a distance of 3 m from the end boundary facing the cargo area. In the case of the sides of those superstructures and deckhouses, such insulation shall be carried up to the underside of the bridge deck. 2.2 Entrances, air inlets and openings to accommodation spaces, service spaces and control stations shall not face the cargo area. They shall be located on the end bulkhead not facing the cargo area and/or on the outboard side of the superstructure or deckhouse at a distance of at least 4% of the length of the ships but not less than 3 m from the end of the superstructure or deckhouse facing the cargo area. This distance, however, need not exceed 5 m. In this area doors to those spaces not having access to accommodation spaces, service spaces and control stations, such as cargo control stations, provision rooms, store-rooms and engine rooms may be permitted provided that the boundaries of the spaces are insulated to "A-60" standard. Bolted plates for the removal of machinery may be fitted within the limits of such areas. Navigating bridge doors and wheelhouse windows may be located within this area, so long as they are so designed that a rapid and efficient gas and vapour tightening of the navigating bridge can be ensured. 2.3 Windows and side scuttles facing the cargo area and on the sides of the superstructures and deck-houses within the limits specified in 2.2 shall be of the fixed (non-opening) type 38) . Such windows and side scuttles, except wheelhouse windows, shall be constructed to "A-60" class standard and shall be of an approved type, except the "A-0" class standard is acceptable for windows and sidescuttles outside the limits specified in 2.1. 2.4 Skylights to cargo pump rooms shall be of steel, shall not contain any glass and shall be capable of being closed from outside the pump room. 2.5 Furthermore the requirements of Section 24, Paragraph A.4 are to be observed. 3. Structure, bulkheads within accommodation and service spaces and details of construction For the application of the requirements of D.2, D.3 and D.9 to tankers, only method IC as defined in D.2.1.1 shall be used. 4. Fire integrity of bulkheads and decks 4.1 In lieu of D.4 and in addition to complying with the specific provisions for fire integrity of bulkheads and decks mentioned elsewhere in this Section the minimum fire integrity of bulkheads and decks shall be as prescribed in Tables 22.7 and 22.8. 4.2 The following requirements shall govern application of the Tables : Tables 22.7 and 22.8 shall apply respectively to the bulkhead and deck separating adjacent spaces. 4.3 For determining the appropriate fire integrity standards to be applied to divisions between adjacent spaces, such spaces are classified according to their fire risk as shown in categories [1] to [10] below. Where the contents and use of a space are such that there is a doubt as to its classificationfor the purpose of this regulation, or where it is possible to assign two or more classifications to a space, it shall be treated as a space within the relevant category having the most stringent boundary requirements. Smaller, enclosed rooms within a space that have less than 30% communicating openings to that spaceareconsideredseparatespaces.Thefireintegrityoftheboundarybulkheadsofsuchsmallerroomsshallbeasprescribed in Tables 22.7 and 22.8. The title of each category is intended tobe typical rather than restrictive. The number in parentheses preceding each category refers to the applicable column or row in the Tables. [1] Control stations Spaces containing emergency sources of power and lighting. Wheelhouse and chartroom. Spaces containing the ship's 38) Reference is made to the Fire Test Procedure Code, Annex 1, Part 3, adopted by IMO by Resolution MSC 61(67). BKI - Rules for Hull - 2014
- 386. F Section 22 - Structural Fire Protection on Board Seagoing Ships22-46/48 radio equipment. Fire control stations. Control room for propulsion machinery when located outside the machinery space. Spaces containing centralized fire alarm equipment. [2] Corridors Corridors and lobbies. [3] Accommodation spaces Spaces used for public spaces, lavatories, cabins, offices, hospitals, cinemas, games and hobbies rooms, barber shops, pantries containing no cooking appliances and similar spaces. [4] Stairways Interior stairways, lifts, totally enclosed emergency escape trunks and escalators (other than those wholly contained within the machinery spaces) and enclosures thereto. In this connection, a stairway which is enclosed only at one level shall be regarded as part of the space from which it is not separated by a fire door. [5] Service spaces (low risk) Lockers and store-rooms not having provisions for the storage of flammable liquids and having areas less than 4 m2 and drying rooms and laundries. [6] Machinery spaces of category A Spaces and trunks to such spaces which contain: internal combustion machinery used for main propulsion; or internalcombustionmachineryusedforpurposesotherthanmainpropulsionwhere suchmachineryhasintheaggregate a total power output of not less than 375 kW; or any oil-fired boiler or oil fuel unit. [7] Other machinery spaces Spaces, other than machinery spaces of category A, containing propulsion machinery, boilers, oil fuel units, steam andinternalcombustionengines,generatorsandmajorelectricalmachinery,oilfillingstations,refrigerating,stabilizing, ventilationandair conditioningmachinery, andsimilar spaces, andtrunks tosuch spaces. Electricalequipmentrooms (auto-telephone exchange and air-conditioning duct spaces). [8] Cargo pump rooms Spaces containing cargo pumps and entrances and trunks to such spaces. [9] Service spaces (high risk) Galleys, pantries containing cooking appliances, saunas, paint and lamp rooms, lockers and store-rooms having areas of4m2 ormore,spacesforthestorageofflammableliquids,andworkshopsotherthanthoseformingpartofthemachinery spaces. [10] Open decks Open deck spaces and enclosed promenades having little or no fire risk. Air spaces (the space outside superstructures and deckhouses). 4.4 Continuous "B" class ceilings or linings, in association with the relevant decks or bulkheads, may be accepted as contributing wholly or in part, to the required insulation and integrity of a division. 4.5 External boundaries which are required in D.3.1 to be of steel or other equivalent material may be pierced for the fitting of windows and sidescuttles provided that there is not requirement for such boundaries to have "A" class integrity elsewhere in these requirements. Similarly, in such boundaries which are not required to have "A" class integrity, doors may be of materials to meet the requirements of their application. 4.6 Permanentapprovedgastightlightingenclosuresforilluminatingcargopumproomsmaybepermittedinbulkheads BKI - Rules for Hull - 2014
- 387. Section 22 - Structural Fire Protection on Board Seagoing Ships F 22-47/48 anddecksseparatingcargopumproomsandotherspacesprovidedtheyareofadequatestrengthandtheintegrityandgastightness of the bulkhead or deck is maintained. 4.7 Construction and arrangement of saunas. See B.11.6. Table 22.7 Fire integrity of bulkheads separating adjacent spaces Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Control stations [1] A-03 A-0 A-60 A-0 A-15 A-60 A-15 A-60 A-60 6 Corridors [2] C B-0 B-0 A-01 B-0 A-60 A-0 A-60 A-0 6 Accommodation spaces [3] C B-0 A-01 B-0 A-60 A-0 A-60 A-0 6 Stairways [4] B-0 A-01 B-0 A-01 A-60 A-0 A-60 A-0 6 6 Service spaces (low risk) [5] C A-60 A-0 A-60 A-0 6 Machinery spaces of category A [6] 6 A-0 A-04 A-60 6 Other machinery spaces [7] A-02 A-0 A-0 6 Cargo pump rooms [8] 6 A-60 6 Service spaces (high risk) [9] A-02 6 Open decks [10] - Notes to be applied to Tables 22.7 and 22.8 as appropriate 1. For clarification as to which applies, see D.3 and D.5 2. Where spaces are of the same numerical category and superscript 2 appears, a bulkhead or deck of the rating shown in the Tables in only required when the adjacent spaces are for a different purpose, e.g. in category [9]. A galley next to a galley does not require a bulkhead but a galley next to a paint room requires an "A-0" bulkhead. 3. Bulkheads separating the wheelhouse, chartroom and radio room from each other may be "B-0" rating. 4. BulkheadsanddecksbetweencargopumproomsandmachineryspacesofcategoryAmaybepenetratedbycargopumpshaftglands andsimilarglanded penetrations,provided thatgastightsealswith efficientlubrication orothermeansofensuring the permanence of the gas seal are fitted in way of the bulkhead or deck. 5. Fire insulation need not be fitted if the machinery space in category [7] has little or no fire risk. 6. Where a 6 appears in the Tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class standard. BKI - Rules for Hull - 2014
- 388. F Section 22 - Structural Fire Protection on Board Seagoing Ships22-48/48 Table 22.8 Fire integrity of decks separating adjacent spaces Space above [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Space below Control stations [1] A-0 A-0 A-0 A-0 A-0 A-60 A-0 - A-0 6 Corridors [2] A-0 6 6 A-0 6 A-60 A-0 - A-0 6 Accommodation spaces [3] A-60 A-0 6 A-0 6 A-60 A-0 - A-0 6 Stairways [4] A-0 A-0 A-0 6 A-0 A-60 A-0 - A-0 6 Service spaces (low risk) [5] A-15 A-0 A-0 A-0 6 A-60 A-0 - A-0 6 Machinery spaces of category A [6] A-60 A-60 A-60 A-60 A-60 6 A-605 A-0 A-60 6 Other machinery spaces [7] A-15 A-0 A-0 A-0 A-0 A-0 6 A-0 A-0 6 Cargo pump rooms [8] - - - - - A-04 A-0 6 - 6 Service spaces (high risk) [9] A-60 A-0 A-0 A-0 A-0 A-60 A-0 - A-02 6 Open decks [10] 6 6 6 6 6 6 6 6 6 - See notes under Table 22.7 BKI - Rules for Hull - 2014
- 389. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings A, B for Bulk Cargo and Heavy Cargo 23-1/27 Section 23 Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo A. Strengthenings for Bulk Cargo and Heavy Cargo 1. General 1.1 For ships, occasionally or regularly carrying heavy cargo, such as iron, ore, phosphate etc., and not intended to get the notation "BULK CARRIER" (see B.) or "ORE CARRIER" (see C.) affixed to their character of classification Strengthenings according to the following regulations are recommended. 1.2 Ships complying withthese requirements will get the following notation affixed to their character of classification "STRENGTHENED FOR HEAVY CARGO". 1.3 It is recommended to provide adequate strengthening or protectionofstructuralelementswithintheworking range of grabs. Note Multi-purpose vessels which occasionally carry dry cargoes in bulk and are not determined as bulk carriers in accordance with SOLAS, Ch. IX, Reg. 1.6 have to fulfil the regulations of resolution MSC.277 (85). 2. Double bottom 2.1 Where longitudinal framing is adopted for the double bottom, the spacing of plate floors should, in general, not be greater than the height of the double bottom. The scantlings of the inner bottom longitudinals are to be determined for the load of the cargo according to Section 9, B. For the longitudinal girder system, see Section 8, B.7.5. 2.2 Where transverse framing is adopted for the double bottom, plate floors according to Section 8, B.6. are to be fitted at every frame in way of the cargo holds. 2.3 For strengthening of inner bottom, deep tank tops etc. in way of grabs, see B.4.3. 2.4 In the drawings to be submitted, details are to be given regarding the loads resulting from the cargo, upon which the calculations are based. 3. Longitudinal strength The longitudinal strength of the ship is to comply with the requirements of Section 5 irrespective of the ship's length. B. Bulk Carriers 1. General 1.1 Bulk carriers built in accordance with the following requirements will get the Notation "BULK CARRIER" affixed to their Character of Classification. Entries will be made into the certificate as to whether specified cargo holds may be empty in case of alternating loading. Additional indications of the types of cargo for which the ship is strengthened may be entered into the Certificate. Such a ship is considered in this Section a "Single Side Skin Bulk Carrier" when one or more cargo holds are bound by the side shell only or by two watertight boundaries, one of which is the side shell, which are less than 1000 mm apart. The distance between the watertight boundaries is to be measured perpendicular to the side shell. When the distance is 1000 mm or above in cargo length area, such a ship is considered a “Double Side Skin Bulk Carrier“. BKI - Rules for Hull - 2014
- 390. B Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-2/27 For accessibility see Section 1, D.1. 1.2 The requirements of Sections 1 to 22 apply to bulk carriers unless otherwise mentioned in A.1.1 is also to be observed. 1.3 For hull structural design of bulk carriers with L > 90 m, contracted for construction on or after 1 April 2006 and in accordance with the definition in 1.4, the IACS Common Structural Rules for Bulk Carrier are applicable. In addition to BULK CARRIER these ships will be assigned the Notation CSR. 1.4 Bulk carrier according to the IACS Common Structural Rules means a ship which is constructed generally with single deck, double bottom, top-side tanks and hopper side tanks in cargo spaces, with single or double side skin construction in cargo length area and is intended primarily to carry dry cargo in bulk. Typical midship sections are given in Fig. 23.14. 1.5 For bulk carriers carrying also oil in bulk also Section 24, G. applies. 1.6 Where reduced freeboards according to ICLL shall be assigned, the respective requirements of the ICLL are to be observed. 1.7 The scantlings of the bottom construction are to be determined on the basis of direct calculations according to Section 8, B.8. For ships according to Section 5, G., D. has to be observed in addition. 1.8 For corrosion protection for cargo hold spaces see Section 38, G. 1.9 For dewatering requirements of forward spaces of bulk carrier, see Rules for Machinery Installations , Volume III Section 11, N. 1.10 For water ingress detection system of bulk carrier, see Rules for Electrical Installations, Volume IV Section 18. 2. Longitudinal strength The requirements of A.3. apply. For alternate loading conditions Section 8, B.8.2.2 is to be observed. For ships of 150 m in length and above, Section 5, G. is to be considered. 3. Definitions k = material factor according to Section 2, B.2. tK = corrosion addition according to Section 3, K pbc = bulk cargo pressure as defined in Section 4, C.1.4. 4. Scantlings of bottom structure 4.1 General The scantlings of double bottom structures in way of the cargo holds are to be determined by means of direct calculations according to Section 8, B.8. For ships according to Section 5, G., D. has to be observed in addition. 4.2. Floors under corrugated bulkheads Plate floors are to be fitted under the face plate strips of corrugated bulkheads. A sufficient connection of the corrugated bulkhead elements to the double bottom structure is to be ensured. Under the inner bottom, scallops in the above mentioned plate floors are to be restricted to those required for crossing welds. The plate floors as well as the face plate strips are to be welded to the inner bottom according to the stresses to be transferred. In general, full or partial penetration welding is to be used, see also E.4.1.1. 4.3 Inner bottom and tank side slopes 4.3.1 The thickness of the inner bottom plating is to be determined according to Section 8, B.4. BKI - Rules for Hull - 2014
- 391. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings B for Bulk Cargo and Heavy Cargo 23-3/27 When determining the load on inner bottom pi , a cargo density of not less than 1 t/m3 is to be used. For determining scantlings of tank side slopes the load pi is not to be taken less than the load which results from an angle of heel of 20E. 4.3.2 Where the plating has been designed according to the following formula, in connection with 9. the Notation "G" may be entered into the Certificate behind the Character of Classification : tG = [mm] The thickness, however, need not exceed 30 mm. Note The stressing of the inner bottom plating depends mainly on the use of grabs, therefore, damage of plating cannot be excluded, even in case of compliance with the above recommendation. 4.3.3 Sufficient continuity of strength is to be provided for between the structure of the bottom wing tanks and the adjacent longitudinal structure. 5. Side Structures 5.1 Side longitudinals, longitudinal stiffeners, main frames The scantlings of side longitudinals are to be determined according to Section 9, B. The longitudinal stiffeners at the lower tank side slopes are to have the same section modulus as the side longitudinals. Their scantlings are also to be checked for the load according to 4.3.1. For the longitudinal stiffeners of the topside tanks within the upper flange Section 9, B.1.5 is to be observed. 5.2 Main frames and end connection The section modulus of main frames of single side skin bulk carrier is to be increased by at least 20% above the value required by Section 9, A.2.1.1. The section modulus W of the frame and bracket or integral bracket, and associated shell plating, at the locations shown in Fig. 23.1, is not to be less than twice the section modulus WF required for the frame midspan area. The dimensions of the lower and upper brackets are not to be less than those shown in Fig. 23.2. Structural continuity with the upper and lower end connections of side frames is to be ensured within topsides and hopper tanks by connecting brackets as shown in Fig. 23.3. Frames are to be fabricated symmetrical sections with integral upper and lower brackets and are to be arranged with soft toes. The side frame flange is to be curved (not knuckled) at the connection with the end brackets. The radius of curvature is not to be less than r [mm], given by : r = where bf and tf are the flange width and thickness of the brackets, respectively [mm]. The end of the flange is to be sniped. In ships with L < 190 m, mild steel frames may be asymmetric and fitted with separate brackets. The face plate or flange of the bracket is to be sniped at both ends. Brackets are to be arranged with soft toes. The web depth to thickness ratio of frames is not to exceed the following values : = for symmetrically flanged frames = for asymmetrically flanged frames The outstanding flange b1 is not to exceed 10 times the flange thickness, see Fig. 23.1. In way of the foremost hold, side frames of asymmetrical section are to be fitted with tripping brackets at every two frames according to Section 9, A.5.5. BKI - Rules for Hull - 2014
- 392. B Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-4/27 Where proof of fatigue strength according to Section 20 is carried out for the main frames, this proof is to be based on the scantlings which do not include the 20% increase in section modulus. For bulk carrier ship configurations which incorporate hopper and topside tanks the minimum thickness of frame webs in cargo holds and ballast holds is not to be less than : tw,min = [mm] C = 1,15 for the frame webs in way of the foremost hold = 1,00 for the frame webs in way of other holds where L need not be taken greater than 200 m. The thickness of the brackets at the lower frame ends is not to be less than the required web thickness tw of the frames or tw,min + 2,0 mm, whichever is the greater value. The thickness of the frame upper bracket is not to be less than the greater of tw and tw,min. 5.3 Minimum thickness of side shell plating The thickness of side shell plating located between hopper and upper wing tanks is not to be less than tp,min [mm], given by : tp,min = [mm] 5.4 Weld connections of frames and end brackets Double continuous welding is to be adopted for the connections of frames and brackets to side shell, hopper and upper wing tank plating and web to face plates. For this purpose, the weld throat is to be (see Fig. 23.1) : – 0,44 · t in zone “a” – 0,40 · t in zone “b” where t is the plate thickness of thinner of the two connected members. Where the hull form is such to prohibit an effective fillet weld, edge preparation of the web of frame and bracket may be required, in order to ensure the same efficiency as the weld connection stated above. 6. Topside tanks 6.1 The plate thickness of the topside tanks is to be determined according to Section 12. 6.2 Where the transverse stiffening system is applied for the longitudinal walls of the topside tanks and for the shell plating in way of topside tanks, the stiffeners of the longitudinal walls are to be designed according to Section.12, the transverse frames at the shell according to Section 9, A.3. 6.3 The buckling strength of top side tank structures is to be examined in accordance with Section 3, F. 6.4 Sufficient continuity of strength is to be provided for between the structure of the topside tanks and the adjacent longitudinal structure. 7. Transverses in the wing tanks Transverses in the wing tanks are to be determined according to Section 12, B.3. for the load resulting from the head of water or for the cargo load. The greater load is to be considered. The scantlings of the transverses in the lower wing tanks are also to be examined for the loads according to 4.3.1. 8. Cargo hold bulkheads The following requirement apply to cargo hold bulkheads on the basis of the loading conditions according to Section 5, A.4. For vertically corrugated transverse cargo hold bulkheads on ships according to Section 5, G. the requirements of E. apply in addition, where the strength in the hold flooded condition has to be ensured. BKI - Rules for Hull - 2014
- 393. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings B for Bulk Cargo and Heavy Cargo 23-5/27 Fig. 23.1 Side frame of single side skin bulk carrier Fig. 23.2 Dimensions of the upper and lower bracket of the side frames Fig. 23.3 Connecting bracket in the hopper tank 8.1 The scantlings of cargo hold bulkheads are to be determined on the basis of the requirements for tank structures according to Section 12, B., where the load pbc according to Section 4, C.1.4 is to be used for the load p. BKI - Rules for Hull - 2014
- 394. B Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-6/27 8.2 The scantlings are not to be less than those required for a watertight bulkhead according to Section 11. The plate thickness is in no case to be taken less than 9,0 mm. 8.3 The scantlings of the cargo hold bulkheads are to be verified by direct calculations. 8.4 Above vertically corrugated bulkheads, transverse girders with double webs are to be fitted below the deck, to form the upper edge of the corrugated bulkheads. They are to have the following scantlings : - web thickness = thickness of the upper plate strake of the bulkhead - depth of web = - face plate (thickness) = 1,5 times the thickness of the upper plate strake of the bulkhead. See also E.4.1.3. 8.5 Vertically corrugated transverse cargo hold bulkheads are to have a plane stiffened strip of plating at the ship's sides. The width of this strip of plating is to be 0,15 H where the length of the cargo hold is 20 m. Where the length of the cargo hold is greater/smaller, the width of the strip of plating is to be increased/reduced proportionally. 9. Hatchway coamings, longitudinal bulkheads 9.1 Coamings The scantlings of the hatchway coaming plates are to be determined such as to ensure efficient protection against mechanical damage by grabs. The coaming plates are to have a minimum thickness of 15 mm. Stays shall be fitted at every alternate frame. The longitudinal hatchway coamings are to be extended in a suitable manner beyond the hatchway corners. In way of the hatchway corners full penetration welding by means of double bevel T-joints or single bevel T-joints may be required for connecting the coaming with the deck plating. See also Section 17. 9.2 Longitudinal bulkheads Where longitudinal bulkheads exposed to grabs have got a general corrosion addition according to Section 3, K.2. of tK = 2,5 mm in connection with 4.3.2 and 9.1 the Notation G may be entered into the Certificate behind the Character of Classification. 10. Loading information for Bulk Carriers, Ore Carriers and Combination Carriers 10.1 General, definitions 10.1.1 These requirements are additional to those specified in Section 5, A.4.3 and apply to Bulk Carriers, Ore Carriers and Combination Carriers of 150 m length and above, and are minimum requirements for loading information. 10.1.2 All ships falling into the category of this Section are to be provided with an approved loading manual and an approved computer-based loading instrument. 10.1.3 The following definition apply : Loading manual is a document which in addition to the definition given in Section 5, A.4.1.3 describes : – for bulk carriers, envelope results and permissible limits of still water bending moments and shear forces in the hold flooded condition according to Section 5, G. – which cargo hold(s) or combination of cargo holds might be empty at full draught. If no cargo hold is allowed to be empty at full draught, this is to be clearly stated in the loading manual. – maximum allowable and minimum mass required of cargo and double bottom contents of each hold as a function of the draught at mid hold position. – maximum allowable and minimum required mass of cargo and double bottom contents of any two adjacent holds as a function of the mean draught in way of these holds. This mean draught may be calculated by averaging the draught of the two mid-hold positions. – maximumallowable tank top loading together with specification of the nature of cargo for cargoes other than bulk BKI - Rules for Hull - 2014
- 395. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings B, C for Bulk Cargo and Heavy Cargo 23-7/27 cargoes. – maximum allowable load on deck and hatch covers. If the vessel is not approved to carry load on deck or hatch covers, this is to be clearly stated in the loading manual. – the maximum rate of ballast change together with the advice that a load plan is to be agreed with the terminal on the basis of the achievable rates of change of ballast. Loading instrument is an approved computer system which in addition to the requirements given in Section 5, A.4.1.3 shall be capable to ascertain that : – allowable mass of cargo and double bottom contents in way of each cargo hold as a function of the ship's draught at mid-hold position – allowable mass of cargo and double bottom contents in any two adjacent cargo holds as a function of the mean draught in way of these holds, and – the still water bending moments and shear forces in the hold flooded condition according to Section 5, G. are within permissible values. 10.2 Conditions of approval of loading manuals In addition to the requirements given in Section 5, A.4.2 the following loading conditions, subdivided into departure and arrival conditions as appropriate, are to be included in the Loading Manual: – alternate light- and heavy cargo loading conditions at maximum draught, where applicable. – homogeneous light and heavy cargo loading conditions at maximum draught. – ballast conditions including those conditions, where ballast holds are filled when the adjacent topwing-, hopper- and double bottom tanks are empty. – short voyage conditions where the vessel is to be loaded to maximumdraught but with limited amount of bunkers. – multiple port loading/unloading conditions. – deck cargo conditions, where applicable. – typical loading sequences where the vessel is loaded from commencement of cargo loading to reaching full dead weight capacity, for homogeneous conditions, the relevant part load conditions and alternate conditions, where applicable. Typical unloading sequences for these conditions shall also be included. The typical loading/ unloading sequences shall also be developed to not exceed applicable strength limitations. The typical loading sequences shall also be developed paying due attention to loading rate and the deballasting capability 1) . – typical sequences for change of ballast at sea, where applicable. 10.3 Condition of approval of loading instruments The loading instrument and its operation manual are subjected to approval. In addition to the requirements given in Section 5, A.4.5.1 the approval is to include : – acceptance of actual hull girder bending moment limits for all read out points. – acceptance of actual hull girder shear force limits for all read out points. – acceptance of limits for each mass of cargo and double bottom contents of hold as a function of draught. – acceptance of limits for mass of cargo and double bottom contents in any two adjacent holds as a function of the mean draught in way of these holds. C. Ore Carriers 1. General 1.1 Ore carriers are generally single-deck vessels with the machinery aft and two continuous longitudinal bulkheads 1 ) Reference is made to IACS recommendation no. 83 (August 2003), “Note to Annexes to IACS unified Requirements S1A on Guidance for Loading/ Unloading Sequence for Bulk Carriers. BKI - Rules for Hull - 2014
- 396. C, D Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-8/27 with the ore cargo holds fitted between them, a double bottom through out the cargo length area and intended primary to carry ore cargoes in the centre hold only. 1.2 Ships built in accordance with the following requirements will get the Notation "ORE CARRIER" affixed to their Character of Classification. Entries will be made into the Certificate as to whether specified cargo holds may be empty in case of alternating loading. Additional indications of the types of cargo for which the ship is strengthened may be entered into the Certificate. 1.3 For ships subject to the provisions of this paragraph the requirements of B. are applicable unless otherwise mentioned in this sub-section. 1.4 For ore carriers carrying also oil in bulk also Section 24, G. applies. 1.5 Where reduced freeboards according to ICLL shall be assigned, the respective requirements of the ICLL are to be observed. 2. Double bottom 2.1 Forachieving good stability criteria in the loaded condition the double bottombetween the longitudinal bulkheads should be as high as possible. 2.2 The strength of the double bottom structure is to comply with the requirements given in B.4. 3. Transverse and longitudinal bulkheads 3.1 The spacing of transverse bulkheads in the side tanks which are to be used as ballast tanks is to be determined according to Section 24, as for tankers. The spacing of transverse bulkheads in way of the cargo hold is to be determined according to Section 11. 3.2 The scantlings of cargo hold bulkheads exposed to the load of the ore cargo are to be determined according to B.8. The scantlings of the side longitudinal bulkheads are to be at least equal to those required for tankers. D. Allowable hold loading, considering flooding 1. General These requirements apply to all bulk carriers, defined in Section 5, G. The loading in each hold is not to exceed the allowable loading according to 4. and shall not exceed the design hold loading in intact condition. 2. Load model 2.1 General The loads to be considered as acting on the double bottom are those given by the external sea pressures and the combination of the cargo loads with those induced by the flooding of the hold to which the double bottom belongs to. The most severe combinations of cargo induced loads and flooding loads are to be used, depending on the loading conditions included in the loading manual: – homogeneous loading conditions – non-homogeneous loading conditions – packed cargo conditions (such as steel mill products) For each loading condition, the maximum bulk cargo density to be carried is to be considered in calculating the allowable hold loading limit. 2.2 Inner bottom flooding head The flooding head hf (see Fig. 23.4) is the distance [m], measured vertically with the ship in the upright position, from the inner bottom to a level located at a distance df [m], from the baseline : BKI - Rules for Hull - 2014
- 397. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings D for Bulk Cargo and Heavy Cargo 23-9/27 df is in general : – H for the foremost hold – 0,9 @ H for the other holds For ships less than 50.000 tdw with Type B freeboard, df is : – 0,95 @ H for the foremost hold – 0,85 @ H for the other holds 3. Shear capacity of the double bottom The shear capacity C of the double bottom is defined as the sum of the shear strength at each end of : – all floors adjacent to both hoppers, less one half of the strength of the two floors adjacent to each stool, or transverse bulkhead if no stool is fitted, see Fig. 23.5 – all double bottom girders adjacent to both stools, or transverse bulkheads if no stool is fitted Where in the end holds, girders or floors run out and are not directly attached to the boundary stool or hopper girder, their strength is to be evaluated for the one end only. The floors and girders to be considered are those inside the hold boundaries formed by the hoppers and stools (or transverse bulkheads if no stool is fitted). The hopper side girders and the floors directly below the connection of the bulkhead stools (or transverse bulkheads if no stool is fitted) to the inner bottom are not to be included. When the geometry and/or the structural arrangement of the double bottom are such to make the above assumptions inadequate, the shear capacity C of double bottom is to be calculated by direct calculations. In calculating the shear strength, the net thickness of floors and girders is to be used. The net thickness tnet [mm] is given by: tnet = t - 2,5 [mm] t = thickness [mm], of floors and girders Fig. 23.4 Flooding head hf of the inner bottom BKI - Rules for Hull - 2014
- 398. D Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-10/27 Fig. 23.5 Girders and floors in the double bottom 3.1 Floor shear strength The floor shear strength in way of the floor panel adjacent to hoppers Sf1 [kN], and the floor shear strength in way of the openings in the outmost bay (i.e. that bay which is adjacent to the hopper) Sf2 [kN], are given by the following expressions: = = Af = sectional area [mm2 ], of the floor panel adjacent to hoppers Af,h = net sectional area [mm2 ], of the floor panel in way of the openings in the outmost bay (i.e. that bay which is adjacent to the hopper) ta = allowable shear stress [N/mm2 ], to be taken equal to the lesser of = and For floors adjacent to the stools or transverse bulkheads, as identified in 3., Ja may be taken as ReH = minimum upper yield stress [N/mm2 ], of the hull structural steel a = spacing of stiffening members [mm], of panel under consideration 01 = 1,10 02 = 1,20 = 1,10, where appropriate reinforcements are fitted BKI - Rules for Hull - 2014
- 399. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings D for Bulk Cargo and Heavy Cargo 23-11/27 3.2 Girder shear strength The girder shear strength in way of the girder panel adjacent to stools (or transverse bulkheads, if no stool is fitted) Sg1 [kN], and the girder shear strength in way of the largest opening in the outmost bay (i.e. that bay which is closer to stool, or transverse bulkhead, if no stool is fitted) Sg2 [kN], are given by = = Ag = minimum sectional area [mm2 ], of the girder panel adjacent to stools (or transverse bulkheads, if no stool is fitted) Ag,h = net sectional area [mm2 ], of the girder panel in way of the largest opening in the outmost bay (i.e. that bay which is closer to stool, or transverse bulkhead, if no stool is fitted) Ja = allowable shear stress [N/mm2 ], as given in 3.1 01 = 1,10 02 = 1,20 = 1,10, where appropriate reinforcements are fitted 4. Allowable hold loading Calculating the allowable hold loading HL [t], the following condition are to be complied with : HL = the lesser of HL1 and HL2 HL1 = HL2 = HLint HLint = max. perm. hold loading for intact condition F = 1,10 in general = 1,05 for steel mill products Dc = cargo density [t/m3 ], for bulk cargoes see 2.1; for steel products, Dc is to be taken as the density of steel V = volume [m3 ], occupied by cargo assumed flattened at a level h1 h1 = For bulk cargoes, X is the lesser of X1 and X2 given by: X1 = X2 = Z + D · g · (E - hf · perm) perm = cargo permeability, (i.e. the ratio between the voids within the cargo mass and the volume occupied by the cargo); need not be taken greater than 0,3. For steel products, X may be taken as X1 using a value for perm according to the type of products (pipes, flat bars, coils etc.) harmonized with BKI. D = 1,025 [t/m3 ], sea water density g = 9,81 [m/s2 ], gravitational acceleration E = (nominal ship) immersion [m] for flooded hold condition = df – 0,1 H Z = the lesser of Z1 and Z2: Z1 = [kN/m2 ] BKI - Rules for Hull - 2014
- 400. D, E Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-12/27 Z1 = Z2 = Ch = shear capacity of the double bottom [kN], as defined in 3., considering, for each floor, the lesser of the shear strengths Sf1 and Sf2 (see 3.1) and, for each girder, the lesser of the shear strengths Sg1 and Sg2 (see 3.2) Ce = shear capacity of the double bottom [kN], as defined in 3., considering, for each floor, the shear strength Sf1 (see 3.1) and, for each girder, the lesser of the shear strengths Sg1 and Sg2 (see 3.2) = [m2 ] = [m2 ] n = number of floors between stools (or transverse bulkheads, if no stool is fitted) Si = spacing of ith - floor [m] BDB,i = BDB – aR for floors whose shear strength is given by Sf1, see 3.1 = BDB,h for floors whose shear strength is given by Sf2, see 3.1 BDB = breadth of double bottom [m] between hoppers, see Fig. 23.6 BDB,h = distance [m] between the two considered openings, see Fig. 23.6 aR = spacing [m], of double bottom longitudinals adjacent to hoppers. Fig. 23.6 Effective distance BDB and BDB,h for the calculation of shear capacity E. Evaluation of Scantlings of Corrugated Transverse Watertight Bulkheads in Bulk Carriers Considering Hold Flooding 1. Application and definitions These requirements apply to all bulk carriers with L > 150 m, intended for the carriage of solid bulk cargoes having bulk density of 1,0 [t/m3 ], or above, with vertically corrugated transverse watertight bulkheads. The net thickness tnet is the thickness obtained by applying the strength criteria given in 4. The required thickness is obtained by adding the corrosion addition tK, given in 6., to the net thickness tnet In this requirement, homogeneous loading condition means a loading condition in which the ratio between the highest and the lowest filling ratio, evaluated for each hold, does not exceed 1,20, to be corrected for different cargo densities 2. Load model 2.1 General The loads to be considered as acting on the bulkheads are those given by the combination of the cargo loads with those BKI - Rules for Hull - 2014
- 401. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings E for Bulk Cargo and Heavy Cargo 23-13/27 induced by the flooding of one hold adjacent to the bulkhead under examination. In any case, the pressure due to the flooding water alone is to be considered. The most severe combinations of cargo induced loads and flooding loads are to be used for the check of the scantlings of each bulkhead, depending on the loading conditions included in the loading manual : – homogeneous loading conditions – non-homogeneous loading conditions considering the individual flooding of both loaded and empty holds. The specified design load limits for the cargo holds are to be represented by loading conditions defined in the loading manual. Non-homogeneous part loading conditions associated with multiport loading and unloading operations for homogeneous loading conditions need not to be considered according to these requirements. Holds carrying packed cargoes (e.g. steel products) are to be considered as empty holds for this application. Unless the ship is intended to carry, in nonhomogeneous conditions, only iron ore or cargo having bulk density equal to or greater than 1,78 [t/m3 ], the maximum mass of cargo which may be carried in the hold shall also be considered to fill that hold up to the upper deck level at centre line. 2.2 Bulkhead corrugation flooding head The flooding head hf (see Fig. 23.7) is the distance [m], measured vertically with the ship in the upright position, from the calculation point to a level located at a distance df [m], from the baseline. df is in general : – H for the aft transverse corrugated bulkhead of the foremost hold – 0,9 @ H for the other bulkheads Where the ship is to carry cargoes having bulk density less than 1,78 t/m3 in non-homogeneous loading conditions, the following values can be assumed for df : – 0,95 @ H for the aft transverse corrugated bulkhead of the foremost hold – 0,85 @ H for the other bulkheads For ships less than 50.000 tdw with Type B freeboard df is : – 0,95 @ H for the aft transverse corrugated bulkhead of the foremost hold – 0,85 @ H for the other bulkheads Where the ship is to carry cargoes having bulk density less than 1,78 [t/m3 ] in non-homogeneous loading conditions, the following values can be assumed : – 0,9 @ H for the aft transverse corrugated bulkhead of the foremost hold – 0,8 @ H for the other bulkheads. BKI - Rules for Hull - 2014
- 402. E Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-14/27 Fig. 23.7 Flooding head hf of a corrugated bulkhead 2.3 Pressure in the non-flooded bulk cargo loaded holds At each point of the bulkhead, in way of length R according to Fig. 23.8 and Fig. 23.9 the pressure pc [kN/m2 ], is given by: pc = Dc · g · h1 · n Dc = bulk cargo density [t/m3 ] g = 9,81 [m/s2 ], gravitational acceleration h1 = vertical distance [m], from the calculation point to the horizontal plane corresponding to the level height of the cargo (see Fig. 23.7), located at a distance d1 [m], from the baseline n = ( = angle of repose of the cargo, that may generally be taken as 35° for iron ore and 25° for cement. The force Fc [kN], acting on a corrugation is given by : = e1 = spacing of corrugations [m], see Fig. 23.8 hLS = mean height of the lower stool [m], from the inner bottom hDB = height of the double bottom [m] 2.4 Pressure in the flooded holds 2.4.1 Bulk cargo holds Two cases are to be considered, depending on the values of d1 and df. a) df > d1 At each point of the bulkhead located at a distance between d1 and df from the baseline, the pressure pc,f [kN/m2 ], is given by : pc,f = D · g · hf D = 1,025 [t/m3 ], sea water density At each point of the bulkhead located at a distance lower than d1 from the baseline, the pressure pc,f [kN/m2 ], is given by: pc,f = D · g · hf + [Dc - D (1 - perm)] g · h1 · n perm = permeability of cargo, to be taken as 0,3 for ore (corresponding bulk cargo density for iron ore may generally be taken as 3,0 [t/m3 ]), coal cargoes and for cement (corresponding bulk cargo density for cement may generally be taken as 1,3 [t/m3 ]) BKI - Rules for Hull - 2014
- 403. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings E for Bulk Cargo and Heavy Cargo 23-15/27 The force Fc,f [kN], acting on a corrugation is given by : = pc,f,le = pressure [kN/m2 ], at the lower end of thecorrugation b) df < d1 At each point of the bulkhead located at a distance between df and d1 from the baseline, the pressure pc,f [kN/m2 ], is given by : pc,f = Dc · g · h1 · n At each point of the bulkhead located at a distance lower than df from the baseline, the pressure pc,f [kN/m2 ], is given by: pc,f = D · g · hf + [Dc · h1 - D (1 - perm) · hf ] g · n The force Fc,f [kN], acting on a corrugation is given by : = 2.4.2 Pressure in empty holds due to flooding water alone At each point of the bulkhead, the hydrostatic pressure pf induced by the flooding head hf is to be considered. The force Ff [kN], acting on a corrugation is given by : Ff = 2.5 Resultant pressure and force 2.5.1 Homogeneous loading conditions At each point of the bulkhead structures, the resultant pressure p [kN/m2 ], to be considered for the scantlings of the bulkhead is given by : p = pc,f - 0,8 · pc The resultant force F [kN], acting on a corrugation is given by : F = Fc,f - 0,8 · Fc BKI - Rules for Hull - 2014
- 404. E Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-16/27 Fig. 23. 8 Span R of the corrugation (longitudinal section) Note For the definition of R , the internal end of the upper stool is not to be taken more than a distance from the deck at the centre line equal to: – 3 times the depth of corrugations, in general – 2 times the depth of corrugations, for rectangular stool Fig 23.9 Span R of the corrugation (transverse section) BKI - Rules for Hull - 2014
- 405. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings E for Bulk Cargo and Heavy Cargo 23-17/27 2.5.2 Non homogeneous loading conditions At each point of the bulkhead structures, the resultant pressure p [kN/m2 ], to be considered for the scantlings of the bulkhead is given by : p = pc,f The resultant force F [kN], acting on a corrugation is given by : F = Fc,f 3. Bending moment and shear force in the bulkhead corrugations The bending moment M and the shear force Q in the bulkhead corrugations are obtained using the formulae given in 3.1 and 3.2. The M and Q values are to be used for the checks in 4.2. 3.1 Bending moment The design bending moment M [kN • m], for the bulkhead corrugations is given by : M = F = resultant force [kN], as given in 2.5 R = span of the corrugation [m], to be taken according to Fig. 23.8 and 23.9 3.2 Shear force The shear force Q [kN], at the lower end of the bulkhead corrugations is given by : Q = 0,8 · F F = as given in 2.5 4. Strength criteria 4.1 General The following criteria are applicable to transverse bulkheads with vertical corrugations, see Fig. 23.8. For ships of 190 m of length and above, these bulkheads are to be fitted with a lower stool, and generally with an upper stool below deck. For smaller ships, corrugations may extend from inner bottom to deck. However, if any stools are fitted, they are to comply with the requirements in 4.1.1 and 4.1.2. See also B.8.4. The corrugation angle k shown in Fig. 23.8 is not to be less than 55°. Requirements for local net plate thickness are given in 4.7. In addition, the criteria as given in 4.2 and 4.5 are to be complied with. The thicknesses of the lower part of corrugations considered in the application of 4.2 and 4.3 are to be maintained for a distance from the inner bottom (if no lower stool is fitted) or the top of the lower stool not less than 0,15 @ R. The thicknesses of the middle part of corrugations as considered in the application of 4.2 and 4.4 are to be maintained to a distance from the deck (if no upper stool is fitted) or the bottom of the upper stool not greater than 0,3 @ R. The section modulus of the corrugation in the remaining upper part of the bulkhead is not to be less than 75% of that required for the middle part, corrected for different yield stresses. 4.1.1 Lower stool The height of the lower stool is generally to be not less than 3 times the depth of the corrugations. The thickness and material of the stool top plate is not to be less than those required for the bulkhead plating above. The thickness and material of the upper portion of vertical or sloping stool side plating within the depth equal to the corrugation flange width from the stool top is not to be less than the required flange plate thickness and material to meet the bulkhead stiffness requirement at lower end of corrugation. The thickness of the stool side plating and the section modulus of the stool side stiffeners is not to be less than those required according to Section 11, B. on the basis of the load model in 2. The ends of stool side vertical stiffeners are to be attached to brackets at the upper and lower ends of the stool. The distance d from the edge of the stool top plate to the surface of the corrugation flange is to be not less than the corrugation flange plate thickness, measured from the intersection of the outer edge of corrugation flanges and the centre BKI - Rules for Hull - 2014
- 406. E Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-18/27 line of the stool top plate, see Fig. 23.12. The stool bottom is to be installed in line with double bottom floors and is to have a width not less than 2,5 times the mean depth of the corrugation. The stool is to be fitted with diaphragms in line with the longitudinal double bottomgirders for effective support of thecorrugated bulkhead. Scallops in the brackets and diaphragms in way of the connections to the stool top plate are to be avoided. Where corrugations are cut at the lower stool, corrugated bulkhead plating is to be connected to the stool top plate by full penetration welds. The stool side plating is to be connected to the stool top plate and the inner bottom plating by either full penetration or deep penetration welds, see Fig. 23.13. The supporting floors are to be connected to the inner bottom by either full penetration or deep penetration welds, see Fig. 23.13. 4.1.2 Upper stool The upper stool, where fitted, is to have a height generally between 2 and 3 times the depth of corrugations. Rectangular stools are to have a height generally equal to 2 times the depth of corrugations, measured from the deck level and at hatch side girder. The upper stool is to be properly supported by girders or deep brackets between the adjacent hatch-end beams. The width of the stool bottom plate is generally to be the same as that of the lower stool top plate. The stool top of non rectangular stools is to have a width not less then 2 times the depth of corrugations. The thickness and material of the stool bottom plate are to be the same as those of the bulkhead plating below. The thickness of the lower portion of stool side plating is not to be less than 80 % of that required for the upper part of the bulkhead plating where the same material is used. The thickness of the stool side plating and the section modulus of the stool side stiffeners is not to be less than required according to Section 11, B. on the basis of the load model in 2. The ends of stool side stiffeners are to be attached to brackets at the upper and lower ends of the stool. Diaphragms are to be fitted inside the stool in line with and effectively attached to longitudinal deck girders extending to the hatch end coaming girders for effective support of the corrugated bulkhead. Scallops in the brackets and diaphragms in way of the connection to the stool bottom plate are to be avoided. 4.1.3 Alignment At deck, if no stool is fitted, two transverse reinforced beams are to be fitted in line with the corrugation flanges. At bottom, if no stool is fitted, the corrugation flanges are to be in line with the supporting floors. Corrugated bulkhead plating is to be connected to the inner bottom plating by full penetration welds. The plating of supporting floors is to be connected to the inner bottomby either full penetration or deep penetration welds, see Fig. 23.13. The thickness and material properties of the supporting floors are to be at least equal to those provided for the corrugation flanges. Moreover, the cut-outs for connections of the inner bottom longitudinals to double bottom floors are to be closed by collar plates. The supporting floors are to be connected to each other by suitably designed shear plates. Stool side plating is to align with the corrugation flanges and stool side vertical stiffeners and their brackets in lower stool are to align with the inner bottom longitudinals to provide appropriate load transmission between these stiffening members. Stool side plating is not to be knuckled anywhere between the inner bottom plating and the stool top. 4.2 Bending capacity and shear stress t The bending capacity is to comply with the following relationship : M = bending moment [kN q m], as given in 3.1 Wle = section modulus of one half pitch corrugation [cm3 ], at the lower end of corrugations, to be calculated according to 4.3 Wm = section modulus of one half pitch corrugation [cm3 ], at the mid-span of corrugations, to be calculated according to 4.4 Fa,le = allowable stress [N/mm2 ], as given in 4.5, for the lower end of corrugations Fa,m = allowable stress [N/mm2 ], as given in 4.5, for the mid-span of corrugations In no case is Wm to be taken greater than the lesser of 1,15 q Wle and 1,15 q W’le for calculation of the bending capacity, W’le being defined below. In case shedders plates are fitted which : – are not knuckled – are welded to the corrugations and the top of the lower stool by one side penetration welds or equivalent BKI - Rules for Hull - 2014
- 407. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings E for Bulk Cargo and Heavy Cargo 23-19/27 – are fitted with a minimum slope of 45° and their lower edge is in line with the stool side plating – have thicknesses not less than 75 % of that provided by the corrugation flange – and material properties at least equal to those provided by the flanges or gusset plates are fitted which: – are in combination with shedder plates having thickness, material properties and welded connections in accordance with the above requirements – have a height not less than half of the flange width – are fitted in line with the stool side plating – are generally welded to the top of the lower stool by full penetration welds, and to the corrugations and shedder plates by one side penetration welds or equivalent – have thickness and material properties at least equal to those provided for the flanges the section modulus Wle [cm3 ], is to be taken not larger than the value W’le [cm3 ], given by : W’le = Wg = section modulus of one half pitch corrugation [cm3 ], of the corrugations calculated, according to 4.4, in way of the upper end of shedder or gusset plates, as applicable Q = shear force [kN], as given in 3.2 hg = height [m], of shedders or gusset plates, as applicable (see Fig. 23.10 and 23.11) e1 = as given in 2.3 pg = resultant pressure [kN/m2 ], as defined in 2.5, calculated in way of the middle of the shedders or gusset plates, as applicable Fa = allowable stress [N/mm2 ], as given in 4.5 Stresses t are obtained by dividing the shear force Q by the shear area. The shear area is to be reduced in order to account for possible non-perpendicularity between the corrugation webs and flanges. In general, the reduced shear area may be obtained by multiplying the web sectional area by (sin k), k being the angle between the web and the flange (see Fig. 23.8). When calculating the section modulus and the shear area, the net plate thicknesses are to be used. The section modulus of corrugations are to be calculated on the basis of the following requirements given in 4.3 and 4.4. 4.3 Section modulus at the lower end of corrugations The section modulus is to be calculated with the compression flange having an effective flange width, bef , not larger than as given in 4.6.1. If the corrugation webs are not supported by local brackets below the stool top (or below the inner bottom) in the lower part, the section modulus of the corrugations is to be calculated considering the corrugation webs 30 % effective. a) Provided that effective shedder plates, as defined in 4.2, are fitted (see Fig. 23.10), when calculating the section modulus of corrugations at the lower end (cross-section 1 in Fig. 23.10), the area of flange plates [cm2 ], may be increased by )Af = [cm2 ] (not to be taken greater than 2,5q b q tf) b = width [m], of the corrugation flange, see Fig. 23.8 tsh = net shedder plate thickness [mm] tf = net flange thickness [mm] b) Provided that effective gusset plates, as defined in 4.2, are fitted (see Fig. 23.11), when calculating the section modulus of corrugations at the lower end (cross-section 1 in Fig. 23.11), the area of flange plates [cm2 ], may be increased by )Af = [cm2 ] BKI - Rules for Hull - 2014
- 408. E Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-20/27 hg = height of gusset plate [m], see Fig. 23.11, not to be taken greater than : hg = [m] agu = width of the gusset plates [m] = 2 q e1 – b [m] tf = net flange thickness [mm], based on the as built condition c) If the corrugation webs are welded to a sloping stool top plate which has an angle not less than 45° with the horizontal plane, the section modulus of the corrugations may be calculated considering the corrugation webs fully effective. In case effective gusset plates are fitted, when calculating the section modulus of corrugations the area of flange plates may be increased as specified in b) above. No credit can be given to shedder plates only. For angles less than 45°, the effectiveness of the web may be obtained by linear interpolation between 30% for 0° and 100% for 45°. Fig. 23.10 Shedder plates Fig. 23.11 Gusset plates and shedder plates BKI - Rules for Hull - 2014
- 409. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings E for Bulk Cargo and Heavy Cargo 23-21/27 Fig. 23.12 Excess end d of the stool top plate Fig. 23.13 Connection by deep penetration welds Fig. 23.14 Single and double side skin bulk carrier BKI - Rules for Hull - 2014
- 410. E Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-22/27 4.4 Section modulus of corrugations at cross-sections other than the lower end The section modulus is to be calculated with the corrugation webs considered effective and the compression flange having an effective flange width, bef, not larger than as given in 4.6.1. 4.5 Allowable stress check The normal and shear stresses s and t are not to exceed the allowable values sa and ta [N/mm2 ], given by : Fa = ReH Ja = 0,5 · ReH ReH = the minimum upper yield stress [N/mm2 ], of the hull structural steel 4.6 Effective compression flange width and shear buckling check 4.6.1 Effective width of the compression flange of corrugations The effective width bef, in m, of the corrugation flange is given by : bef = Ce q b where: Ce = for $ > 1.25 Ce = 1.0 for $ < 1.25 $ = tf = net flange thickness, in mm b = width, in m, of the corrugation flange (see Fig. 23.8) ReH = minimum upper yield stress, in N/mm2 , of the material E = modulus of elasticity of the material, in N/mm2 , to be assumed equal to 2,06 × 105 for steel 4.6.2 Shear buckling The buckling check for the web plates at the corrugation ends is to be performed according to Section 3, F. The buckling factor is to be taken as follows : K = The shear stress t has to be taken according to 4.2 and the safety factor S is 1,05. 4.7 Local net plate thickness The bulkhead local net plate thickness tnet [mm], is given by : = Fw = plate width [m], to be taken equal to the width of the corrugation flange or web, whichever is the greater, see Fig. 23.8 p = resultant pressure [kN/m2 ], as defined in 2.5, at the bottom of each strake of plating; in all cases, the net thickness of the lowest strake is to be determined using the resultant pressure at the top of the lower stool, or at the inner bottom, if no lower stool is fitted or at the top of shedders, if shedder or gusset/shedder plates are fitted For built-up corrugation bulkheads, when the thicknesses of the flange and web are different, the net thickness of the narrower plating is to be not less than tnet,n [mm], given by : = an = the width [m], of the narrower plating, see Fig. 23.8 The net thickness of the wider plating [mm], is not to be taken less than the maximum of the following values tw1 and tw2: BKI - Rules for Hull - 2014
- 411. Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings E, F for Bulk Cargo and Heavy Cargo 23-23/27 = = where tnp < actual net thickness of the narrower plating and not to be greater than tw1. 5. Shedder and gussed plates The thickness and stiffening of effective gusset and shedder plates, as defined in 4.3, is to determined according to Section 12, B. on the basis of the load model in 2. 6. Corrosion addition and steel renewal The corrosion addition tK is to be taken equal to 3,5 mm. F. Harmonised Notations and Corresponding Design Loading Conditions for Bulk Carriers 1. Application 1.1 These requirements are applicable to bulk carriers as defined in B.1., see Fig. 23.14, having a length L of 150 m or above and contracted for new construction on or after 1st July 2003. 1.2 The loading conditions listed under 3. are to be checked regarding longitudinal strength as required by Section 5, local strength, capacity and disposition of ballast tanks and stability. The loading conditions listed under 4. are to be checked regarding local strength. 1.3 For the loading conditions given in this document, maximum draught is to be taken as moulded summer load line draught. 1.4 These requirement are not intended to prevent any other loading conditions to be included in the loading manual for which calculations are to be submitted see Section 5, nor is it intended to replace in any way the required loading manual/instrument. 1.5 A bulk carrier may in actual operation be loaded differently from the design loading conditions specified in the loading manual, provided limitations for longitudinal and local strength as defined in the loading manual and loading instrument onboard and applicable stability requirements are not exceeded. 2. Harmonized notations and annotations 2.1 Notations Bulk Carriers are to be assigned one of the following Notations. BC-C : for bulk carriers designed to carry dry bulk cargoes of cargo density less than 1,0 t/m3 BC-B : for bulk carriers designed to carry dry bulk cargoes of cargo density of 1,0 t/m3 and above with all cargo holds loaded in addition to BC-C conditions. BC-A : for bulk carriers designed to carry dry bulk cargoes of cargo density of 1,0 t/m3 and above with specified holds empty at maximum draught in addition to BC-B conditions. 2.2 Additional Notations The following additional Notations are to be provided giving further detailed description of limitations to be observed during operation as a consequence of the design loading condition applied during the design in the following cases: – {maximum cargo density ... t/m3 } for Notations BC-A and BC-B if the maximum cargo density is less than 3,0 tonnes/m3 BKI - Rules for Hull - 2014
- 412. F Section 23 - Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy Cargo 23-24/27 – {no MP} for all Notations when the vessel has not been designed for loading and unloading in multiple ports in accordance with the conditions specified in 5.3 – {holds, a, b, ... may be empty} for Notation BC-A 3. Design loading conditions (General) 3.1 BC-C Homogeneous cargo loaded condition where the cargo density corresponds to all cargo holds, including hatch-ways, being 100 % full at maximum draught with all ballast tanks empty. 3.2 BC-B As required for BC-C, plus: Homogeneous cargo loaded condition with cargo density 3,0 tonnes/m3 , and the same filling ratio (cargo ma