Your vessel is proceeding up a channel, and you see a pair of range lights that are in line dead ahead. The chart indicates that the direction of this pair of lights is 093°T, and the variation is 6°E. If the heading of your vessel at the time of the sighting is 097° per standard magnetic compass, what is the correct deviation?

Question

Accepted Answer

Option B: 10°W. The range lights provide a True bearing of 093°T. With a compass heading of 097°psc, the Compass Error is 4°W. Since Compass Error equals Variation plus Deviation, and Variation is 6°E, the deviation must be 10°W to satisfy the equation (6°E + 10°W = 4°W).