boatswain

A boatswain ( BOH-sən, formerly and dialectally also BOHT-swayn; also known as bo's'n, bos'n, or bosun, also known as a deck boss, or a qualified member of the deck department, or the third hand on a fishing vessel) 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.