chap6ex6-2


Exercise 6 – 2

Exercise 6 – 2



Exercise 6-2 A, B, C & D

  1. Relative bearings of the observed boat are advancing towards the bow.
    The boat will pass ahead of you. Take no action.
  2. Relative bearings of the observed boat are retarding towards the stern.
    The boat will pass behind you.
  3. Relative bearings of the observed boat are somewhat consistent. You are
    on a collision course. There is no guarantee that he sees you. Take a positive
    action to avoid collision.
  4. Convert compass bearings to relative bearings.
    • RB = MB-MH (you have been taught this in the format MB=MH+RB)
    • RB = CB-CH (assume deviation is 0º)
    • 1530 RB = 270º – 240º = 030º
    • 1533 RB = 290º – 240º = 050º
    • 1536 RB = 310º – 240º = 070º
    • Can you do the calculations above instantly?

    The relative bearings of the observed boat are retarding towards the stern.
    The boat will pass behind you. Take no action.
    Note that the conversion from compass bearings to relative bearings took time.
    In most cases, especially with high speed power boats, determining collision
    course is a real time “Seaman’s Eye” problem. When time is an issue, stick to relative bearings.
    Sailboat: When performning a collision course solution in a tacking situation, take
    collision course bearings with a hand bearing compass. This will be the only constant
    frame of reference when the boat is tacking.