Magnetic compasses are adjusted on board with appropriate compensators to reduce the deviation caused by the ship's magnetism. The greater the distance to magnetic interference fields, the smaller the deviation.
The following compensators are available:
B+C compensations are to adjust the longitudinal (B) and transverse (C) field. This compensation is generally recommended for all magnetic compasses. For most of our spherical compasses mounted correctors are available, which are inserted into the housing.
The D compensation is used to adjust the weak or volatile magnetic field from the iron hull of a ship. It can neutralize up to 6° deviation. The D compensation is more suitable for coastal navigation, because the deviation can vary when passing magnetic latitudes due to the self-induction of the magnet inside the card system.
The K compensation neutralizes the deviation caused by heeling of the ship. In an uncompensated vertical field, the compass card moves synchronously towards port or starboard when the ship is rolling.
It is generally recommended to use a certified compass adjuster for proper compensation.