On 11 January your 0450 ZT position is LAT 38°42'N, LONG 14°16'W. You observe Polaris bearing 358.5°pgc. At the time of the observation the helmsman noted that he was heading 160°pgc and 173°psc. The variation is 9°W. What is the deviation for that heading?

Correct Answer: Option A — 3°W

Polaris true bearing is practically 360°T (or 000°T). Comparing the observed Polaris pgc bearing (358.5°) with true yields gyro error. Since gyro and pgc are equivalent here, applying variation (9°W) to true course gives magnetic. Comparing magnetic to standard compass (173°psc) yields 3°W deviation.