How Do I Know If My Boat Is Too Noisy?
How Do I Know If My Boat Is Too Noisy
- If a boat drives by at speed and people on shore find it hard to hear each other or have to raise their voices to be heard, then the boat is considered excessively loud and probably will not meet the proposed decibel limits.
- If you have through the hull exhausts without any muffler, then your boat is illegal today.
- If you have through the hull exhausts with mufflers but do not meet the first point or the proposed dB limits.
- You can use a decibel meter to measure the sound pressure of your boat.
- SAE J2005 – Stationary Measurement: Proposed limit is 88 dB(AS) measured three feet behind the transom at idle.
- SAE J1970 – Shoreline Measurement: Proposed limit is 75 dB(AS) as the boat passes by at any distance, measured from shore.
Small hand-held decibel meters can be purchased from many sites on the internet. There are numerous Apps available for smart phones. Recommend apps: NIOSH Sound Level Meter and Decibel X Sound Meter. Ensure that the decibel scale is set to A and the speed to slow.
How Do I Make My Boat Quiet Enough to Meet Proposed Legislation
- If you have a Captains Choice, have it permanently disengaged ie. on quiet mode
- If you have through the hull exhaust you have a few options:
- Install mufflers either inside the engine box or on the pipe externally. This may or may not be effective enough to meet the standards. Large capacity engines and twin engines may be problematic. Costs for this range from $500 to $1500 per engine and may be able to be done without a mechanic.
- Change the risers on your manifold so that the exhaust is directed via the out-drive to exit through the prop or below the water line when traveling at speed. Costs can vary significantly depending on the current configuration of your engine and exhaust.
- There may be some boats that are designed as racing boats/ocean racers that cannot be adapted to comply. These boats are not legal today on smaller waterways but can be operated 5 nautical miles from land.
Products Available to Help Muffle Boat Noise
Gibson Performance makes mufflers that attach to the pipe as it exits the transom. The manufacturer claims they are tested up to 1,200 HP with minimal or no power loss and they warrant that the product will make your boat compliant with SAE J2005 at 88 dB(AS).