Mufflers and Noise Level Limits

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 75 dBA.
• 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.