Your ship is entering port from sea, and you sight a pair of range lights. When in line, they bear 315° per standard magnetic compass. The chart shows that the range bearing is 312°T, and that variation is 6°W. What is the deviation of your compass at the time of the sighting?

Question

Your ship is entering port from sea, and you sight a pair of range lights. When in line, they bear 315&deg; per standard magnetic compass. The chart shows that the range bearing is 312&deg;T, and that variation is 6&deg;W. What is the deviation of your compass at the time of the sighting?

Accepted Answer

Option A: 3&deg;E. Compass error is the algebraic difference between True and compass bearings. With a True bearing of 312° and a compass bearing of 315°, the error is 3°W. Since Compass Error = Variation + Deviation, solving for deviation (3°W - 6°W) results in 3°E, confirming the magnetic compass is influenced by local shipboard fields.

Your ship is entering port from sea, and you sight a pair of range lights. When in line, they bear 315&deg; per standard magnetic compass. The chart shows that the range bearing is 312&deg;T, and that variation is 6&deg;W. What is the deviation of your compass at the time of the sighting?

Your ship is entering port from sea, and you sight a pair of range lights. When in line, they bear 315° per standard magnetic compass. The chart shows that the range bearing is 312°T, and that variation is 6°W. What is the deviation of your compass at the time of the sighting?