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 343°T, and the variation is 5° west. If the heading of your vessel at the time of the sighting is 344° 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 343&deg;T, and the variation is 5&deg; west. If the heading of your vessel at the time of the sighting is 344&deg; per standard magnetic compass, what is the correct deviation?

Accepted Answer

Option C: 4&deg;E. Compass error is the difference between the True bearing (343°T) and the compass bearing (344°psc), resulting in 1°W error. Since Compass Error = Variation + Deviation, substituting the known values (-1° = -5° + Deviation) confirms that the deviation is 4°E, accounting for the magnetic influence on the compass.