Three weeks ago I got my first ticket for loud exhaust. My boat is a 2002 Formula 271 with a 496HO which had the Formula Silent Thunder Platform on the boat until early this spring. I installed Dana's manifolds and exhaust tips on the boat, which have the mufflers installed in the tips. Dana advertises this system to be 88dba legal? When they conducted the test they told me the exhaust had an average of 98.8dba! The high reading was 103dba and the low was 96.

I don't think this test was done correctly to say the least, but I could be wrong. I did not notice a big change in the noise of the boat when I switched to the Dana system. I never thought the Silent Thunder was loud at all. The Dana system is a little louder, but not much.

Can anybody help me find out more info on how the test is conducted and if the engine is supposed to be at idle during the whole test, or are they supposed to have you start the engine at the beginning of the test when there is no water in the system (of course that is going to be louder than when water is running through the system).

Any help or comments on the subject would be great.

There are a couple ways that they test you, but the most common one is the 1 meter stick test.

I was lucky enough to get tested on Lake George, NY last summer when I backed into the public docks adn my exhaust bouncing off the seawall triggered the rent-a-cops to come over. The guy explained how everything works and said that the test is done at idle and that you have to wait 30 seconds after starting up the boat to get all teh water cycling through. Then they take a meter stick, put it to the back of your transom and attach the DB meter at the end. I have a stock engine/exhaust but still pulled 95.1(limit is 90.0) on the DB meter and got a $50 ticket.

Go under the region section, Great Lakes area and find the thread on exhausts too loud. They talk about how to test in there.

Gibson Mufflers are the way to go.


Gladheater- A lot of times the cops dont test it correctly. We were trained by the same people and we have the same equipment. NExt summer stop by and we will see if it really was 95

Hopefully I will have a new boat by then! I'd like to test the new one to see what it spits out though.

for any decibel test to be done correcty there can be no
refelecting surfaces around you (dock walls,other boats,etc) and
the meter must be in the right position.
The difference in being 1m away and .5m away is 6 db ,
having a dockwall or boat next to you can make it read higher by 3-6db ,etc.
Also what frequencies are these meters reading and what scale or correction are they using? How often are they checking calibrations? Just like a dyno you can make a db meter read anything you want if you know(or dont know) what you are doing.

I would like to add, that the DB meter was set to fast response not slow response which I believe it should be set on? I also think when they test the boat it has to be in the middle of the lake, or you can do a drive-by the pier at 50ft at WOT.
I would like some info on where the rules are written and how the test should be conducted for the lakes in the state of Wisconsin? Any help would be great...court date is coming up.

Thanks

Ask to see the calibration records of the test equipment.
And also ask if the particular unit is traceable with NIST standards?
The meter they used should also have a sticker or label on it showing the last date of calibration, and when it is next due to be calibrated.

But the judge (if a fair judge) should take into account that the test is properly conducted. And, if the Db meter is not properly calibrated, the test is not valid. The Co. I work for is currently going through an ISO type Quality program, and somehow I got designated to head this up (lucky me).
You wouldn't believe the things I've had to send out for calibration, a steel ruler for one, not a tape measure, a steel ruler 36" long 1/16" scale.

Check out this Link...We are going through the same thing
http://www.offshoreonly.com/forums/s...ight=noise+law