Able Rate

In the British Royal Navy in the middle of the 18th century, the term able seaman (abbreviated AB) referred to a seaman with more than two years' experience at sea and considered "well acquainted with his duty". Seamen with no or less than one year experience at sea are referred to as landmen or ordinary seamen respectively.

In 1653 the Royal Navy introduced a new pay scale as part of reforms following defeat in the Battle of Dungeness the previous year. Included in these reforms were, for the first time, separate pay scales for more experienced seamen. It distinguished between an ordinary seaman and an able seaman. The higher ranked able seaman could steer, use the lead and work aloft, traditionally to "hand, reef, and steer." An able seaman received about 25% higher pay than an ordinary seaman.

In time of war (such as the Seven Years' War or the Napoleonic Wars), with many more warships in service, the navy, merchant marine, and privateers competed ferociously for the limited pool of able seamen, leading to the unpopular use of impressment by the Royal Navy to keep its ships manned. In peacetime, with fewer active warships, there was usually a surplus of unemployed able seamen willing to work in the navy. As late as the Napoleonic Wars, the Royal Navy's practice of stopping American ships to press American sailors into involuntary service was one of the main factors leading to the War of 1812 with the United States.

Some notable able seamen from the Royal Navy include:

In the Royal Canadian Navy, able seaman (AB) is the second-lowest of the non-commissioned member ranks, ranking above ordinary seaman and below leading seaman. Able seamen wear a single gold chevron, point down, as an insignia of rank; it is worn on the upper part of both sleeves of the service dress tunic, and on slip-ons on both shoulders on other uniforms.

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