Annex 13 (Magnetic Compasses) to the MCA’s 2002 SOLAS V Publication advises that each magnetic compass required to be carried must be properly adjusted and its table or curve of residual deviations must be available at all times.
Magnetic compasses should be adjusted when: (1) they are first installed; (2) they become unreliable; (3) the ship undergoes structural repairs or alterations that could affect its permanent and induced magnetism; (4) electrical or magnetic equipment close to the compass is added, removed or altered; or (5) a period of two years has elapsed since the last adjustment and a record of compass deviations has not been maintained, or the recorded deviations are excessive or when the compass shows physical defects.
