Requirements to Have 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. 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 |
