A bosun is an officer on a ship who is responsible for the rigging, anchors, cables, sails, and other items that are used to keep a ship running smoothly. He or she is considered to be the foreman of the ship's crew, because he or she issues orders to the deck crew. On a small ship, the bosun may also be the third or fourth mate, meaning that he or she is only a few steps below the captain in seniority.
The term originates from “boatswain,” which is still considered to be a technically correct spelling of the word. Both words stem from a much older English word, batswegen. The batswagen was a boy or follower of the boat, and generally considered to be more like a servant than a member of the crew. The function of the job evolved with the word, which turned into boatswain in the late 1400s. Gradually the pronunciation of the word changed, and the spelling began to reflect that: most sailors use the spelling of “bosun” to refer to boatswains.
Today, the bosun is an important part of the ship's crew. On small boats and sailing ships, he or she still works with the deck crew to coordinate work and organize duties. When the bosun is also a ships mate, he or she is accorded more authority and respect among the crew. On larger ships where the majority of deck tasks are automated, this person is in charge of the deck crew and ceremonially calls them to work using a bosun's pipe, a specially designed whistle.
The bosun's pipe uses a series of tones to convey orders. The sound could be clearly heard over other noises on a busy sailing ship, and in some navies, whistling by crew was forbidden to avoid confusion. The pipe is still used on small ships to relay orders, and in the formal ceremonies of many navies. It was also considered to be a badge of rank, because ordinary seamen were not permitted to wear it.
Traditionally, the bosun has his or her own crew and series of mates. The bosun's first mate was often given punishment duties, for example, and might be left in charge of the deck crew when the bosun was not on duty. The crew works like a well oiled machine to keep the ship safe and running smoothly, and coordination between its members is crucial in an emergency situation.