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Course Outline

Sound Signal 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. The navigation rules for meeting head-on, crossing, and overtaking situations are examples of when sound signals are required.

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 required
26 feet long or longer (Class III or IV) Whistle or other sound-producing device and a bell required

*Federal reservoirs in Iowa include Saylorville, Red Rock, Rathbun, and Coralville Reservoirs.

If on Federally Controlled Waters
Less than 39.4 feet (12 meters) long (includes PWC) Something such as handheld air horn, an athletic whistle, or an installed horn required
39.4 feet (12 meters) long or longer Sound signal should be audible for one-half mile and should last for 4 to 6 seconds
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