Bosun is a nearly broken Mister Handy that only has its head and one thruster left. He has been reprogrammed by Captain Ironsides to serve on the USS Constitution. When asked about his condition, the robot will tell the Sole Survivor that his limbs were lost during combat with the scavengers, a group of looters that are constantly at odds with the robot crew of the Constitution. This is problematic, as Bosun serves as the ship's mechanic. This causes the Sole Survivor's interaction with him.
Last Voyage of the U.S.S. Constitution: Bosun is one of two crew members the Sole Survivor is sent to assist in repairing the ship. Bosun is tasked with repairing the ship's aging electrical cables, but is unable to do so because of his lost limbs. Because of this, he must be helped with replacing the fraying cables with new ones at three points around the ship.