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 014°T, and the variation is 11°E. If the heading of your vessel at the time of the sighting is 009° per standard magnetic compass, what is the correct deviation?
Official USCG Answer & Rule Citation
Correct Answer: Option B — 6°W
Use the formula Compass Error = True - Compass. The range lights provide a True bearing of 014°. With a heading of 009°psc, the total compass error is 5°E. Subtracting the 11°E variation (Error = Variation + Deviation) results in a deviation of 6°W.
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