Your vessel is proceeding up a channel, and you see a pair of range lights that are in line ahead. The chart indicates that the direction of this pair of lights is 196°T, and the variation is 7°E. If the heading of your vessel at the time of the sighting is 192° per standard magnetic compass, what is the deviation?
Official USCG Answer & Rule Citation
Correct Answer: Option C — 3°W
True range is 196°T and variation is 7°E, giving a magnetic value of 189°M. Comparing this to the standard magnetic compass heading of 192°psc yields a deviation of 3°W, following standard deviation calculation methods (Compass West, Magnetic Best).
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