It's the Law: Required Equipment

Sound-Producing Devices

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.

If on State Waters or on Mississippi River, Missouri River, or Federal Reservoirs*
Less than 16 feet long (Class I)	None required, but at least a whistle is recommended
16 feet long or longer but less than 26 feet long (Class II)	Whistle or other sound-producing device
26 feet long or longer (Class III or IV)	Whistle or other sound-producing device and a bell
If on Federally Controlled Waters
Less than 65.6 feet long	Whistle or horn audible for at least one-half mile required
65.6 feet long or longer	Whistle or horn and a bell audible for at least one mile required
* Federal Reservoirs include Saylorville, Red Rock, Rathbun, and Coralville Reservoirs.

Sound Signals

Some common sound signals that you should be familiar with as a recreational boater are as follows. Sound devices

Changing Direction

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 sailboats under sail.

Warning

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.

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Online boating safety handbook last modified: July 11, 2008
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