what is a boatswain
For other uses, see Boatswain (disambiguation). A boatswain (/ËboÊsÉn/, formerly and dialectally also /ËboÊtsweÉªn/), bo's'n, bos'n, or bosun, also known as a Petty Officer or a qualified member of the deck department, is the seniormost rate of the deck department and is responsible for the components of a ship's hull.