On 16 September your vessel's 0736 zone time DR position is LAT 27°34'S, LONG 174°49'E, when an azimuth of the Sun is observed. The chronometer time of the sight is 07h 38m 11s, and the Sun is bearing 079.8° per gyrocompass. The chronometer error is 01m 46s fast, and the variation in the area is 11.0°W. At the time of the sight, the helmsman reports that he was heading 252°pgc and 258° per magnetic compass. What is the deviation of the magnetic compass?

Question

On 16 September your vessel's 0736 zone time DR position is LAT 27&deg;34'S, LONG 174&deg;49'E, when an azimuth of the Sun is observed. The chronometer time of the sight is 07h 38m 11s, and the Sun is bearing 079.8&deg; per gyrocompass. The chronometer error is 01m 46s fast, and the variation in the area is 11.0&deg;W. At the time of the sight, the helmsman reports that he was heading 252&deg;pgc and 258&deg; per magnetic compass. What is the deviation of the magnetic compass?

Accepted Answer

Option C: 3&deg;E. Calculate the true azimuth of the Sun to find the gyro error. With the gyro bearing and true bearing, determine the gyro error. Then, using the relationship between the gyro heading and magnetic heading, calculate the deviation by accounting for the 11.0°W variation, resulting in a deviation of 3°E.