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 283° T, and the variation is 13°E. If the heading of your vessel at the time of the sighting is 278° per standard 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 283&deg; T, and the variation is 13&deg;E. If the heading of your vessel at the time of the sighting is 278&deg; per standard compass, what is the deviation?

Accepted Answer

Option D: 8&deg;W. True heading is 283°. Magnetic heading is True minus Variation (283 - 13 = 270°M). With a compass heading of 278°C, the deviation is the difference between Magnetic and Compass headings. Since the compass reads higher than magnetic, the deviation is 8°W (Compass Best, Magnetic Least, Error West).