Navigation rules require sound signals to be made under certain circumstances. Meeting, crossing and overtaking situations described in the Navigation Rules section are examples of when sound signals are required. Recreational boats are also required to sound signals during periods of reduced visibility.
- Vessels less than 39.4 feet (12 meters) in length (including PWCs) may carry a whistle or horn or some other means to make an efficient sound signal audible for 1/2 mile.
- Vessels 39.4 feet (12 meters) or more in length are required to carry a whistle.
- Vessels 65.6 feet (20 meters) or more in length are required to carry a whistle and a bell.
