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 311°T, and the variation is 8°E. If the heading of your vessel at the time of the sighting is 305° 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 ahead. The chart indicates that the direction of this pair of lights is 311&deg;T, and the variation is 8&deg;E. If the heading of your vessel at the time of the sighting is 305&deg; per standard magnetic compass, what is the correct deviation?

Accepted Answer

Option B: 2&deg;W. True heading is 311°. Magnetic heading is True minus Variation (311 - 8 = 303°M). With a compass heading of 305°C, the deviation is the difference between Magnetic and Compass. Since the compass reads higher than magnetic, the deviation is 2°W (Compass Best, Magnetic Least, Error West).