Boat horns serve several purposes on your vessel and according to the United States Coast Guard (USCG) Navigation Rules, they are a requirement on most vessels. Boats over 65.6 feet in length are required to have a sound-producing device, and most recreational boats must have a whistle or horn that can be heard for up to one mile away. These marine horns help ensure safe passage on the waterways and alert other watercraft of issues or dangers. Boat horns can come in a variety of different styles. From brass ship bells, electronic signal horns, air-horn compressors, and dual horns, OC Boat Supplies carries them all.