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 sound-producing device may be a whistle, horn, or bell that is audible for one-half mile. All vessels on state and federally controlled waters must have a sound-producing device.
Vessels less than 39.4 feet (12 meters) in length, which includes PWCs, are required to carry on board a whistle or horn or some other means to make an efficient sound signal to signal intentions or positions. Vessels that are 39.4 feet (12 meters) or more in length are required to carry on board a whistle or horn, and a bell.
Here are some common sound signals that you should know as a recreational boater.
A short blast lasts one second.
A prolonged blast lasts 4-6 seconds.
One short blast tells other boaters "I intend to pass you on my port (left) side."
Two short blasts tell other boaters "I intend to pass you on my starboard (right) side."
Three short blasts tell other boaters "I am backing up."
Restricted Visibility
One prolonged blast at intervals of not more than two minutes is the signal used by power-driven vessels when underway. One prolonged blast plus two short blasts at intervals of not more than two minutes is the signal used by sailing vessels.
One prolonged blast is a warning signal (for example, used when coming around a blind bend or exiting a slip).
Five or more short, rapid blasts signal danger or signal that you do not understand or that you disagree with the other boater's intentions.
