Through Transom Exhausts

[settimo velo]

I've decided to fit through transom exhausts on my twin V6 installation. I've familiarised myself with the contents of the Merc Manuals - block off plate installation, height of riser above waterline, angle of exhaust pipe etc. Merc do not say much on the subject and don't seem to provide much in the way of a product solution, apart from flaps? I think Merc suggest installing flaps on the pipe ends and water shutters in pipe, which I guess is a necessary precaution to protect the engine from potential water ingress. I was thinking of 4" i/d pipe, based on the rubber pipes that are fitted on the riser to elbow joint. However, this does seem like quite a big pipe and looking at the riser, there is an inner pipe of smaller diameter that could also be used?

If anyone can offer any advice on through transom solutions and point me in the direction of any recommended product that would be a great help. Thanks

 

[bondo]

I was thinking of 4" i/d pipe, based on the rubber pipes that are fitted on the riser to elbow joint. However, this does seem like quite a big pipe and looking at the riser, there is an inner pipe of smaller diameter that could also be used?

Ayuh,.... You have to use the 4" pipes, if ya got 4" risers...
The Inner sleeve is Just the exhaust, you need to let the water mix from the outer pipe...

The V6, runnin' thru-hulls sounds like a Loooong fart...
It ain't no V8...
Think of a Cessna 172 flying overhead, that limp dronein' sound ...

When I yanked the I4 outa my barge, 'n dropped in the 4.3l, I went to thru-hulls....
After the 1st couple of days trollin' 12/ 18 hours a day,...
I've been trying to quiet it down ever since,...
After 12 years, 'n twice as many redesigns,...
I'm selling it, 'n moving up to a bigger V8 powered barge, with thru-prop exhaust...

Good luck with it, but I wouldn't do it....