Re: through transom exhaust w/mercruiser I/O
The friendly (yes, they really are friendly) folks here on these boards convinced me to keep my water-lift mufflers and exhaust below the swim platform.
I was gonna run 4" pipe off the risers and go straight out the back. Then I was gonna keep the stock (above waterline, below swim deck) exhaust location but remove the waterlift mufflers.
I have to say, I never knew how many boaters didn't like the noise (it doesn't bother me). Once I listened to the boating community, I decided it wasn't something I wanted. I like to pull up to friends' marinas and homes and visit. We also have four kids, and while I duck in/out of the Atlantic and run across the Chessie and Deleware Bays, most running is in-shore, near other boats/people.
I have a very nice rumble (502 cubic inches will do that), but it is pleasant underway, and noise doesn't equal speed/power. In my case, I show off my water-lift mufflers like some sort of cool accessory that no one else has.
I say: Worry about something else. The noise gets old, and a big part of boating is the community of people. I'll take them over an open exhaust any day.
BUT... if you want to do it, you need tall risers, 4" pipe to within about 6" of the transom, then exhaust hoses that connect to exhaust thru-hull tips, and a hole saw to cut some holes in the transom.
In a couple of years, 75% of the country will be waiting to ticket you.
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