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 178°T, and the variation is 9°W. If the heading of your vessel at the time of the sighting is 180° per standard magnetic compass, what is the 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 178&deg;T, and the variation is 9&deg;W. If the heading of your vessel at the time of the sighting is 180&deg; per standard magnetic compass, what is the deviation?

Accepted Answer

Option C: 7&deg;E. True heading is 178°. Magnetic heading is True minus Variation (178 - (-9) = 187°M). With a compass heading of 180°C, the deviation is the difference between Magnetic and Compass headings. Since the compass reads lower than magnetic, the deviation is 7°E (Compass Least, Magnetic Best, Error East).