Mufflers and Noise Level Limits

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

• A vessel’s engine must have a factory-installed muffler or exhaust system for noise reduction, or another effective muffling system.
• Michigan law states that a vessel’s muffler or exhaust system must prevent noise in excess of:
  • 90 decibels at idle from three feet away and...
  • 75 decibels when measured from the shore.