Mariner69
Well-Known Member
I agree with Stormforce; the diagram is completely wrong in misusing the terms.
With regard to deviation it depends on which instrument you use to take the bearing. If the deviation card has been produced on the ship's compass and the reading taken off there using an azimuth ring then deviation will require applying before variation considered ; in effect you can use a single number the Compass Error to correct. Where a hand bearing compass is concerned it will probably have a different deviation curve to the ship's compass but there is no reason why you shouldn't calibrate and use the deviation curve you have produced. Where you are using the hand bearing compass for anti-collision bearings then it doesn't matter whether or not any errors are applied since you are only interested in the rate of change and direction thereof.
With regard to deviation it depends on which instrument you use to take the bearing. If the deviation card has been produced on the ship's compass and the reading taken off there using an azimuth ring then deviation will require applying before variation considered ; in effect you can use a single number the Compass Error to correct. Where a hand bearing compass is concerned it will probably have a different deviation curve to the ship's compass but there is no reason why you shouldn't calibrate and use the deviation curve you have produced. Where you are using the hand bearing compass for anti-collision bearings then it doesn't matter whether or not any errors are applied since you are only interested in the rate of change and direction thereof.
