In periods of reduced visibility or whenever a vessel operator needs to signal his or her intentions or position, a sound-producing device is essential. The navigation rules for meeting head-on, crossing, and overtaking situations are examples of when sound signals are required.
- Arizona state law does not require that vessels carry a sound-producing device; however, it is always a good idea to have one on board.
- Federal law requires that vessels operating on federally controlled waters, such as the Colorado River and Lake System, be equipped with sound-producing device(s). On federally controlled waters:
- Vessels less than 39.4 feet (12 meters), which includes PWC, must have some way of making an efficient sound signal. Examples are a handheld air horn, an athletic whistle, an installed horn, etc. A human voice is not acceptable.
- Vessels that are 39.4 feet (12 meters) or more in length must have a sound-producing device that can produce an efficient sound signal. The sound signal should be audible for one-half mile and should last for 4 to 6 seconds.