Bosun

A boatswain is the most senior rate of the deck department and is responsible for the components of a ship's hull. The boatswain supervises the other members of the ship's deck department and typically is not a watchstander, except on vessels with small crews. Additional duties vary depending upon ship, crew and circumstances. The name is also known as bo's'n, bos'n, bosun, deck boss, a qualified member of the deck department or the third hand on a fishing vessel.