I just had a Decibel test by the Illinois Conservation Police on my 2000 353 with HP500 efi's and using the silent thunder exhaust. They are telling me I'm at 92.4 and state law is 89. He tested 3 feet back and about 4 feet off the water and there was about a 10 mile an hour wind. There was about 3' of dock off the back end and other than that nothing for about 40'. He tested twice and seemed a little suprised at the reading.

I had all the plugs in the silent thunder platform so it was a muffled as it could be. I have a slight rattle in the platform which may not have helped. I have a call into Formula as I'm told by a couple of mechanics the silent thunder should not produce that kind of a reading.

Has anyone else with the same setup been tested and/or have any ideas?

My silent thunder box rattled.....Took it off and ALL the baffles were delaminated and cracked.....took the box off and the rattles went away.

its a 2000 boat, he should have a while before he puts up with the Silent Thunder curse.

Your DNR (Department No Reason) should be using SAE standard J1970, J2005? and
J34. Which means your boat should have been tested under control conditions. Which
means they probably didn't re-calibrate there meter's after testing someone else. And
the J spec should tell them there's tolerance of plus or minus 5 DB's. Hope this helps.
I have the SAE specs burned on a CD at home if I can find the CD I'll post them.

Troutly - as I was doing searches I found a post from you where your 353 ( by the way I own your old 353 now) tested at 90. That would likely get me by if that's where I tested and I wonder if the rattle and/or test conditions could have bumped me up to 92.4.

K-MAN - if you have the test specs I'd love to see them

353Guy

This weekend is the Milwaukee GMAC APBA Offshore race. I'm helping my girl
friend Jen Youngblood secure the Midwest Championship in One Design (the
bat boats). All she has to do is start the race on Saturday. After this weekend, I'll dig up those SAE spec's, download them and zip off to you. You
can also go to your local state DNR website and look up the state regulations
for noise, since the law and the way the DNR or Noise Cops do or enforce
the the rules varies from state to state. Here in Wisconsin the DNR does things differently from district to district. They seem they can't make up there mind how to enforce the noise restrictions and this gives us boaters
the up hand in court. Other words if the DNR can't follow there own rules
they can't give you a ticket and it gets throwing out of court. Hope this
helps.

K-Man