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Compasses — Navigation B — Instruments, Mashit 30

18 questions on compasses, from the Navigation B — Instruments exam of Mashit 30. Magnetic, gyro, fluxgate, deviation and variation. Every question is shown with its correct answer, as in the official question pool.

Practise by topic · All 193 Navigation B — Instruments questions · Mock exam

Questions on Compasses

  1. How will equipment containing loudspeakers, headphones, microphones and batteries affect the vessel's compass? It will disturb the magnetic compass.
  2. What is compass deviation? An error caused by masses of metal and electrical equipment on board.
  3. What is magnetic course? The angle between the vessel's fore-and-aft line and magnetic north.
  4. Which compasses does variation affect equally? A magnetic compass and a fluxgate compass.
  5. What is needed to make a deviation table for a magnetic compass? Answers a and b are correct.
  6. What are the main drawbacks of the mechanical gyrocompass? It needs a continuous power supply and depends on it, and it does not settle immediately when switched on.
  7. Regarding the fluxgate compass, choose the correct answer: Answers a and b are correct.
  8. A compass is an angle-measuring instrument that shows the angle between: Compass north and a given object on the horizon.
  9. A fluxgate compass has the following advantages. Mark the one that does NOT apply: Deviation and variation errors are easy to correct in it.
  10. The most accurate bearing of an object on shore is obtained with: A pelorus.
  11. What can equipment containing loudspeakers, headphones, microphones and batteries affect? It will affect a magnetic compass and throw it off.
  12. Variation affects equally: A magnetic compass and a fluxgate compass.
  13. How does a fluxgate compass work? Answers a and b are correct.
  14. What are the main drawbacks of the mechanical gyrocompass? It needs a continuous power supply and depends on it, it does not settle immediately when switched on, and it develops an error that depends on the latitude and on the course and speed of the vessel it is fitted in.
  15. Which of the following instruments shows the vessel's true course relative to true north? GPS.
  16. Your vessel is going astern, moving towards the east. What course will the magnetic compass show, and what course will the GPS show? Magnetic compass – W; GPS – E.
  17. A stationary vessel heading 150° is turned 30° to port. What course will the magnetic compass show, and what course will the GPS show? Magnetic compass – 120°; GPS – will not respond.
  18. The lubber line of a marine compass is on north. If we turn the compass 90° to the left, where will the lubber line point? West.

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