About the Study Guide

You are looking at a preview of what’s in the timed Iowa Boat Ed Course. Feel free to look around, but you’ll need to register to begin progress toward getting your Iowa Boater Education Certificate.

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Vessel operators may not hear sound signals or voices if the engine is not adequately muffled.

  • The exhaust of every internal combustion engine on any powerboat must be effectively muffled by equipment constructed and in use to reasonably muffle vessel noise.
  • Powerboats must meet the following SAE sound level tests.
    • Stationary sound level test: Engines manufactured before January 1, 1993, must not exceed a noise level of 90 dBA. Engines manufactured on or after January 1, 1993, must not exceed a noise level of 88 dBA.
    • Shoreline sound level test: Engines must not exceed a noise level of 75dBA.
  • All muffling devices used on powerboats must be in good working order and in constant operation to prevent excessive or unusual noise.
  • The use of cutouts is prohibited, except for vessels competing in an authorized marine event.