Emergency Signaling Devices for Recreational Boats
To meet U.S. Coast Guard and State carriage requirements for recreational vessels, you must choose one of these sound-producing devices or something that makes sufficient enough sound to signal navigational intentions:
Horns and Whistles: Horns and whistles are popular for signaling on boats and meet U.S. Coast Guard requirements. They are straightforward to use, work well at close distances, and make a sufficient sound to signal navigational intentions.