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?

Question

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

Accepted Answer

Option C: 3&deg;W. Polaris bearing 358.5°pgc with zero gyro error means the True bearing is 358.5°. With 9°W variation, the Magnetic bearing is 7.5°. The compass heading is 173°psc. Comparing the magnetic bearing to the compass heading reveals a deviation of 3°W, ensuring the compass is corrected for local magnetic influence.

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

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?