Adjust the ship's magnetic compass by swinging through 360° and trimming the B-corrector (fore-and-aft), C-corrector (athwartships), and quadrantal spheres to minimize deviation on all headings. Covers the theory of ship's magnetism, reading the deviation card, compass adjustment procedures per USCG regulations, and the mathematical relationship between variation, deviation, and compass error.
A current deviation card is a US Coast Guard certificate requirement. Compass adjustment is a Chief Mate and Master competency under STCW Table A-II/2 and is tested on the USCG General Navigation examination.