The U.S. Navy occupational rating of Boatswain's Mate (BM) is a designation given by the Bureau of Naval Personnel (BUPERS) to enlisted members who are rated or "striking" for the rating as a deck seaman. The colloquial form of address for a boatswain's mate is 'Boats'. The rating of Boatswain's Mate dates from the American Revolutionary War and is one of the oldest U.S. Navy rates still in continuous existence.
Boatswain's mates train, direct, and supervise personnel in ship's maintenance duties in all activities relating to marlinspike, deck, boat seamanship, painting, upkeep of ship's external structure, rigging, deck equipment, and boats. Boatswain's mates take charge of working parties; perform seamanship tasks; act as petty officer-in-charge of picketboats, self-propelled barges, tugs, and other yard and district craft. They serve in, or take charge of damage control parties. BM's also operate and maintain equipment used in loading and unloading cargo, ammunition, fuel, and general stores. BMs take charge of and supervise UNREP (underway replenishment) procedures and equipment. They are integral to ship's navigation and serve as ship's Helmsman and the ship's Lee Helmsman. In addition they also serve as Rhib (Rigid-hulled inflatable boat) coxswains.