While entering a harbor on a course of 225° per gyrocompass, you take a bearing on a pair of range lights and get 220° per gyrocompass. The bearing on the chart is 217°T. The variation for the area is 6°W, and deviation is 2°W. What course would you steer per gyrocompass to make good a true course of 232°?

Question

While entering a harbor on a course of 225&deg; per gyrocompass, you take a bearing on a pair of range lights and get 220&deg; per gyrocompass. The bearing on the chart is 217&deg;T. The variation for the area is 6&deg;W, and deviation is 2&deg;W. What course would you steer per gyrocompass to make good a true course of 232&deg;?

Accepted Answer

Option D: 235&deg;pgc. Gyro error is 3°W (220°pgc vs 217°T). To make good a True course of 232°, apply the gyro error in reverse. Since the gyro reads 3° high, you must steer 232° + 3° = 235°pgc to compensate for the error and maintain the desired track.