The boatswain's whistle or call originated in the Middle Ages. During the Renaissance and the early modern period, the British Navy used it as a method for communicating orders aboard ship. As a result, it became a symbol for the authority of the boatswain. (Boatswain is pronounced and frequently misspelled as "bosun.") The boatswain's call is used to play a simple series of notes, called pipes, each of which relates to a command, such as "lash up and stow" or "hail."
Hold the boatswain's call firmly between your thumb and index finger. Curl your other fingers gently around it, taking care not to block the hole.
Place the mouthpiece gently between your lips. Blow firmly into the mouthpiece. This produces a low note.
Close your fingers tightly around the rounded lower part of the whistle, called the buoy. This produces a high note.
Trill and warble by moving your tongue inside your mouth as you blow on the call. To trill, roll your tongue against the roof of your mouth as if you were rolling an "R" sound. To warble, move the tongue back and forth across the mouthpiece while alternating between low and high notes.
Play the pipe by alternating low and high notes in the correct patterns. Each pipe has a unique pattern that will be instantly recognisable to the hands on board.