Take a look at the chart above. It’s from the National Institute for Occupational Safety and Health (NIOSH). As you can see, sustained exposure to 85 dB-A and above ain’t good for you. Now browse through your nearest boating magazine and read through the boat tests–the good ones record dB-A throughout the rpm range. Where does your boat’s noise levels fall?
Nobody thinks about it, but I wrote a Seamanship column on the subject several years ago. It can affect your judgement and level of fatigue during long stretches at the helm.
You can get the numbers on your boat yourself, with the same tool most editors–and boat company technicians–use on boat tests. A digital model from Radio Shack will tell you what you need to know. It costs $50 (www.radioshack.com).
To get the best numbers, set the meter to the “A” weighting and “slow” response setting, which does a better job of averaging the sound level for a steadier read. Stick the microphone close to the helm and have everybody shut up, then record the numbers at 500 rpm increments. You’ll notice that on any open-helm boat, whether you have a stern drive with an insulated engine compartment or a whisper quiet four-stroke outboard, wind noise overtakes engine noise shortly after climbing on plane. And not long after that, the sound level will be above the red line on the NIOSH chart above.
For long distance runs, try headphones or earplugs made for shooting sports, motorcycling, or industrial machinery. Try something like these inexpensive QuietEar Reusable Plugs.