On 5 August your 0310 ZT position is LAT 09°02'N, LONG 21°08'W. You observe Polaris bearing 002°pgc. At the time of the observation the helmsman noted that he was heading 316°pgc and 329°psc. The variation is 15°W. What is the deviation for that heading?

Correct Answer: Option D — 0.5°E

Polaris bears 000° True. A bearing of 002° pgc indicates a gyro error of 2° W. Applying this to the heading 316° pgc gives a True heading of 314°. Using the formula True = Compass + Variation + Deviation, 314° = 329° + (-15°) + Deviation, resulting in a deviation of 0.5° E.