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Faithful,

Any benefits of running the exhaust out of the side, besides just looking good? How would someone go about doing this if the person in question had Cabrera's built in fish boxes and exhaust already run outboard of the stringers? How high above the chine would the hole start and how far would the leading edge be from the transom? I'm considering this setup with the 315 Yanmar re-power.

Thanks for any response, John.

John,

I asked the question a while back and the general opinion I got was to go straight out the back. Later I considered the cost of the modification and decided it wasn't worth it for me. For my gas motors I had a hood or diverter over the exhaust which canneled it outwoard and downward. I plan on re-using them after the repower. Some say it makes the noise level in the cockpit rise? I'm not so sure it gets the fumes away from the cockpit as well. But with the yanmars you shouldn't have an issue with sooting or smoke anyway.

br,
JohnD

You asked so my 2 Cents. You dont want it out the side. When the boat rocks it shoots spray up and smoke when drifting. leave it out the back and save your $ for something else wich there will be other things you will want to do with the new 315s, ie( cool guages, oil changing system, flowscans,pyrometers) just to nget started. I think it looks cool at the dock but not when your fishing and diving with freinds. Good luck.

John,Brewster

You guys talked me out of it. My exhaust is already going out the back.
Brewster,
My exhaust is 4" all the way to the transom with no mufflers. I've been told that this is ok, but I've also heard that I need to step up to 5" somewhere along the way. What do you think?

Thanks again, John.

John,
Is 4" marginal or just right for the Yanmar application. 5" is marginal for the Cummins in similar horsepower ranges. If Yanmar is different thats good news for you. If it isn't I can tell you what we learned.
With the exhaust run outboard of the stringers you have roughly 10-11" of deck clearance to play with. 5" Centek vernatone mufflers are 10.5" at the widest point and barely fit. 6" vernatone are at 12" and we couldn't get them to fit.
If fit becomes an issue you may want to look at some of the slimmer muffler choices available.
Centek makes a "Centubular" muffler that is 6" and almost 5' long.
Primex also makes a slim line muffler that incorporates a check valve.
With the outboard mounted mufflers we were able to build 2 insulated 53" stainless drop in boxes. You won't regret going through the extra work to make fish boxes fit. Its really nice packing out to go offshore and carrying only 1 bait cooler.

My boat already had 6" out the back. The 315 lp6s Are 4" out and I mated them under the deck to the 6" out the back with no muflers. They are not too loud for me but you might want them for what you want.

JP, Brewster,

Thanks for the response. Looks like the 4" will work, so I'll try it out without the mufflers and see what happens. The tubes are glassed into the transom real pretty, no flanges, so I'll just forget about that side exhaust business
and keep what I've have..

John,

We have 315s with 5" with the Primex with the check valve and very low on back-pressure. If you end up being at all high on back pressure you can always by-pass some of the exhaust water through a valve out the side to adjust the back pressure to perfection.

Nic

Nick,

That's a damn good idea...If I need to. that's the route I'll go. Thanks, that shure simplifies things.

The boat I got has exhaust out the side.( Gas engines ) I know it is great because when you troll, the fumes don't wash back in area. The only problem I see is a little black soot residue on the vents, but it washes rite off. Of course it is a white boat so black sticks out alot.