Lesson 12 Navigational Instruments
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The document discusses various navigation instruments used to measure direction, distance, speed, and depth at sea. It describes how an azimuth circle and telescopic alidade are used to measure direction by shooting bearings, radar and stadimeters are used to measure distance up to 2000 yards, impeller logs and pit logs are used to measure speed through water by detecting dynamic and static pressure, Doppler speed logs can extremely accurately measure speed using shaft RPM, and a fathometer is used to measure depth below the ship.
Lesson 12 Navigational Instruments
- 1. NS100 Navigation Instrument s Fundamentals of Naval Science
- 2. Measurement of Direction Azimuth Circle
- 4. Measurement of Direction Telescopic Alidade
- 5. Shooting a Bearing Look through the rear sight slot Line up forward wire with center of slot and object Look into prism to obtain bearing (true or relative) Record bearing for plotting.
- 6. Measurement of Distance Radar
- 7. Measurement of Distance Stadimeter - very accurate under 2000 yards
- 9. Measurement of Speed Terms: Speed over Ground - “True” speed, or speed relative to the earth. Speed through the water - Relative speed between the water and the ship, not accounting for the effect of current or seas.
- 10. Measurement of Speed Impeller Log
- 11. Measurement of Speed Pit Log Dynamic pressure static pressure
- 12. Measurement of Speed Doppler Speed Log – can be extremely accurate Shaft RPM vs. speed
- 13. Measurement of Depth Fathometer
- 14. Piloting Instruments Divider and Drawing Compass Parallel Ruler/Parallel Plotter/Parallel Motion Protractor (PMP) Three-Arm Protractor