A boatswain's pipe or boatswain's call (pronounced "Bosun") is a whistle that is made of a tube, called the barrel, that directs air over a grape-sized metal sphere with a hole cut in the top. The player opens and closes the hand over the hole to change the pitch.
The historical use of the boatswain's call was as a signalling device on a ship. Because of its high pitch, it could be heard over the activities of the crew and bad weather. It is now used in the traditional color , sunset and other ceremonies of several navies, sometimes combined with other auditive features: ruffles and flourishes or even a gun salute.
It is also the Official badge of the Quartermaster in the Sea Cadet Corps
