Boatswain's Mates (BM) train, direct, and supervise personnel in ship's maintenance duties in all activities relating to marlinespikes, decks, boat seamanship, painting, upkeep of ship's external structure, rigging, deck equipment, and life boats; take charge of working parties; perform seamanship tasks; act as petty officer-in-charge of picket boats, self-propelled barges, tugs, and other yard and district crafts; and operate and maintain equipment used in loading and unloading cargo, ammunition, fuel, and general stores.