Question 663Navigation General

The correct answer is A) deviation. Magnets in the binnacles of magnetic compasses are used to reduce the effect of deviation. Deviation is the deflection of a compass needle caused by the magnetic fields of the ship's metal hull and equipment. These magnets help to counteract the effects of this local magnetic interference, which can cause the compass to point in a direction other than true north. The other options, local attraction and variation, are related but distinct phenomena that the magnets do not address. Local attraction is the influence of nearby magnetic objects, while variation is the difference between true north and magnetic north.