Boatswain's whistle

A boatswain's whistle is the boatswain's tool for communicating with the crew of a ship without raising his voice. It is still used today on naval ships and traditional sailing ships such as training ships.

By holding the whistle in a certain way, the blowhole can be closed, allowing signals to be given with it. For the sentry, the best-known signal given with it is the call announcing that a person of high rank—such as the commanding officer—is boarding by the side.

The whistle can be part of the uniform worn by members of the scouting water branch. A whistle cord is then attached to the whistle, signifying the wearer's proficiency in signalling.

A boatswain's whistle is the boatswain's tool for communicating with the crew of a ship without raising his voice. It is still used today on naval ships and traditional sailing ships such as training ships. By holding the whistle in a certain way, the blowhole can be closed, allowing signals to be given with it.