Question 615Navigation General

The correct answer is A) A single vertical magnet beneath the compass. When a vessel heels over, the earth's magnetic field will be distorted, causing errors in the compass reading. A single vertical magnet beneath the compass can compensate for these errors by creating a magnetic field that counteracts the distortion. This arrangement is known as "Flinders compensation" and is a common method used to correct for the heeling error in a ship's compass. The other options are incorrect because they do not directly compensate for the heeling error. Magnets placed in trays inside the binnacle (B) and the soft iron spheres on the arms of the binnacle (C) are used for different purposes, such as adjusting the compass for local magnetic influences. The Flinders bar (D) is a separate device used to adjust the compass for the vessel's magnetic fields, but it does not directly compensate for the heeling error.