Klaxon

Klaxon is an electric or electropneumatic sound-signaling device producing a loud honking tone, used aboard ship for alarms (general, fire, abandon-ship) and as a warning horn. The name comes from the Klaxon Signals Company, which patented the diaphragm-and-rotor electric horn around 1908. On modern vessels the whistle and sound appliances for navigational signals must meet COLREGs 1972 Rule 33 and Annex III frequency and range specifications; internal alarm tones are set by SOLAS Chapter III muster and alarm requirements.