A boatswain (pronounced “BOH-sun”) is a senior crew member on a ship who supervises the deck crew and maintains the vessel's equipment. The boatswain makes sure the ship's ropes, sails, anchors, and other gear stay in good working order. Think of the boatswain as the ship's head maintenance supervisor, organizing the daily work that keeps everything running smoothly.

On sailing ships throughout history, the boatswain was one of the most important people aboard. They directed the sailors who climbed the masts, handled the rigging, and performed the dangerous work of operating a ship at sea. A good boatswain knew every rope and pulley on the ship and could spot problems before they became emergencies.

On modern ships, boatswains still exist, though their work has changed with technology. They might oversee painting, repairs, and cargo handling rather than managing sails.

You might see the word spelled bosun or bo'sun in books about sailing or the navy. These are shorter, informal ways to write the same word. In adventure stories set at sea, the boatswain often appears as a tough, experienced sailor who keeps the crew organized and the ship seaworthy.