BTW it is pronounced “Bosun” and the nickname for the rank is “Boats.” Both the Navy and the Coast Guard still have boatswains and boatswain’s mates.
From Wikipedia(United_States_Navy):
“Boatswain’s mates train, direct, and supervise personnel in ship’s maintenance duties in all activities relating to marlinspike, deck, boat seamanship, painting, upkeep of ship’s external structure, rigging, deck equipment, and boats. Boatswain’s Mates take charge of working parties; perform seamanship tasks; act as petty officer-in-charge of picketboats, self-propelled barges, tugs, and other yard and district craft. They serve in, or take charge of damage control parties. BM’s also operate and maintain equipment used in loading and unloading cargo, ammunition, fuel, and general stores. BMs take charge of and supervise UNREP (underway replenishment) procedures and equipment. They are integral to ship’s navigation and serve as ship’s Helmsman. Boatswain’s mates enjoy a normal path of advancement to Chief Warrant Officer and Limited Duty Officer. Candidates must have normal color perception, and no speech impediment.”
There is also the Ship’s Boatswain, “an officer who assists the First Lieutenant by supervising the deck force in the execution of major seamanship functions and the maintenance of topside gear. The Ship’s Boatswain supervises cargo handling and inspects and maintains rigging and deck gear. His duties also include supervising anchoring, mooring, fueling, towing, transferring of personnel and cargo, and the operation and maintenance of ship’s boats. The Ship’s Boatswain is in charge of what the Navy deems “unusual” seamanship operations such as retrieving target drones, and also schedules training for deck division personnel. Another key duty of the Ships’ Boatswain is supervision of the maintenance of abandon-ship equipment and instruction in abandon-ship techniques.”
Boatswain’s are part of the group of folks who are considered to be the guys that actually get the work of the Navy done, the petty officers and the CPO’s, or Chief Petty Officers. My husband retired as a CPO after 22½ years in the Navy.