Able Seaman

The able seaman, universally abbreviated to AB, is a skilled member of the deck crew and a backbone of the ship's practical seamanship. Ranking above the entry-level ordinary seaman and below the petty officers such as the bosun, the AB has gained the sea time, training and certification to be trusted with the full range of deck work. Becoming an AB requires a qualifying period of service at sea and the completion of training to the standards set out in the STCW convention, which recognises the able seafarer deck as a certificated rating.

An AB's duties are varied and hands-on. On the bridge during a sea watch the AB acts as lookout, keeping a proper visual and audible watch as required by the COLREGs, and takes the helm to steer the ship by hand when needed, for instance in confined waters or when the automatic pilot is not appropriate. On deck, ABs handle the mooring lines when berthing and unberthing and work the anchors, rig and operate cargo gear, and carry out the continual maintenance that a ship needs, chipping, painting, greasing, and preserving the hull, deck fittings and equipment against the corrosive marine environment. They also form part of the crew for lifeboat and emergency drills and duties.

The AB rank sits within the traditional career ladder of the deck department. A newcomer may join as an ordinary seaman and, with experience and training, advance to able seaman, and from there potentially to bosun, the senior deck rating who supervises the crew, or pursue further study toward officer qualifications. The competence, reliability and seamanship of the ABs are central to the safe day-to-day running of a ship, particularly in mooring operations, watchkeeping and the maintenance that keeps the vessel seaworthy, and a good AB is a valued and respected member of any crew.