Exhaust system troubling me..

[Reefmagnet]

On our new to us centre cokpit boat, The exhaust from the engine enters a custom - made for the boat - water lock located about 12" down from the heat exchanger utilizing a 180 degree stainless tube inline along the way to allow it to drop this distance in a small space. It then exits via a short tube at the top of the water lock which then passes through a bulkhead, msaking an immediate left turn and then running against a bulkhead along the top of the sole and following the curvature of the hull until it connects to a 1 1/2" through hull before exiting the boat at a point about 4" above the waterline aft of midship on the starboard side of the vessel. The through hull is fitted with a ball valve.

The long and short of all this is that the total distance the exhaust rises above the waterline once it exits the waterlock appears to be less than a foot at the highest (and below the waterline for most of the run). This appears to be the original design and it troubles me because I cannot see how other than keeping the through hull ball valve closed when not operating the engine that water will be prevented from filling the water lock when sailing. Now normally, I would just say that the system is there, it must work BUT the engine in it is new and it is not known what killed the last engine.

Am I worrying for nothing?

[sabray]

I guess the old engine filled with water. I think you are on the right thinking here. Mine goes up to near deck level and then drops so its 2 feet above the water line at the end. Can you creat a higher loop?

[Reefmagnet]

Cheers. I can. I'd have to make a custom goose neck and locate it in a hanging locker, but it's doable. The PO's said the old engine "lost compression" which could mean anything!

[Cheechako]

I'd definitely create a loop just prior to the hull exit if possible. At 4" above the waterline... a little more loading and being parked at a dock with the wind waves slapping the exit fitting could fill the engine gradually. Any reason you couldnt just bend the exhaust hose 180 degrees? Or 90 degree fiberglass fittings are readily available.

[sabray]

Maybe try fisheries supplyhttp://www.fisheriessupply.com/sites...st%20system%20

[sww914]

IMHO You're right, you need a high loop. My exhaust hose (which we replaced) makes a loop just before it exits the boat. I got it high enough that it actually touches the underside of the deck. No risk, potential big reward, maybe $18.00 extra spent.