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

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&deg;T, and the variation is 6&deg;E. If the heading of your vessel at the time of the sighting is 097&deg; per standard magnetic compass, what is the correct deviation?

Accepted Answer

Option D: 10&deg;W. True heading is 093°. Magnetic heading is True minus Variation (093 - 6 = 087°M). With a compass heading of 097°C, the deviation is the difference between Magnetic and Compass. Since the compass reads higher than magnetic, the deviation is 10°W (Compass Best, Magnetic Least, Error West).