You swung ship and compared the magnetic compass against the gyro compass to find deviation. Gyro error is 2°E. The variation is 8°W. Find the deviation on a magnetic compass heading of 057°.

Correct Answer: Option C — 1.5°W

True heading is 057° magnetic plus or minus variation. With 8°W variation, the true heading is 049°. Gyro error is 2°E, so the gyro heading is 047°. Comparing the magnetic compass heading (057°) to the true heading (049°) shows a compass error of 8°W. Subtracting variation yields 1.5°W deviation.