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Old 11-10-2012, 10:12 PM   #41
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I had a Sumnercraft that had an engine mounted very low in it's keel so the exhaust manifold exit was probably below the WL. The exhaust pipe had a rise in it that rose just enough to be above the WL at the slight rise. The PO of that boat left it for long periods of time and rain water slowly rose in the bilge to the point where the exhaust was below the WL. In time the seawater made it's way down the exhaust pipe from it's exit at the transom, into the exhaust manifold, through an open exhaust valve, through the open intake valve (in that particular cyl) and through the intake manifold and into the bilge. The boat sunk at her mooring hanging on her mooring lines. The Sumnercraft had foam flotation chambers and w her mooring lines holding she sat there for a while. Not long of course but the insurance co. decided to replace the engine. But no change was made to the configuration of the exhaust system. After I bought it I planed to make changes. One of the changes I was contemplating was a shut-off valve in the exhaust pipe to prevent any possible ingestion of seawater into the boat. Has anybody put a big ball valve in the exhaust pipe of a wet exhaust boat? I wonder if ball valve would work well in such an environment?
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Old 11-11-2012, 10:11 AM   #42
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Quote:
Originally Posted by manyboats View Post
I had a Sumnercraft that had an engine mounted very low in it's keel so the exhaust manifold exit was probably below the WL. The exhaust pipe had a rise in it that rose just enough to be above the WL at the slight rise. The PO of that boat left it for long periods of time and rain water slowly rose in the bilge to the point where the exhaust was below the WL. In time the seawater made it's way down the exhaust pipe from it's exit at the transom, into the exhaust manifold, through an open exhaust valve, through the open intake valve (in that particular cyl) and through the intake manifold and into the bilge. The boat sunk at her mooring hanging on her mooring lines. The Sumnercraft had foam flotation chambers and w her mooring lines holding she sat there for a while. Not long of course but the insurance co. decided to replace the engine. But no change was made to the configuration of the exhaust system. After I bought it I planed to make changes. One of the changes I was contemplating was a shut-off valve in the exhaust pipe to prevent any possible ingestion of seawater into the boat. Has anybody put a big ball valve in the exhaust pipe of a wet exhaust boat? I wonder if ball valve would work well in such an environment?
Some I/Os have "flapper valves" in their exhaust system supposedly to prevent water ingestion through the exhaust system. Because of the high temperatures and corrosive nature of the exhaust, they have been problematic and Volvo, at least, has discontinued these.

If possible, I think a different solution such as an upward loop in the exhaust system would probably be better.

I'm surprised though, that a manufacturer would not take this into consideration when designing the boat.
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Old 11-11-2012, 11:30 AM   #43
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Ron wrote:
"I'm surprised though, that a manufacturer would not take this into consideration when designing the boat."

Indeed I couldn't believe they did that ... but they did. They (wether I'm talking about the builder or the designer I'm unclear) designed one of the most interesting cleverly designed boats I've ever seen. Lightweight and extremely seaworthy. The boats were of sandwich construction 1" Fir w FG on each side. They had a full keel as deep as my Willard w a rudder to match and w a 98hp 6 cyl engine (same Ford block as the Lehman) they topped out at 20 knots and sipped fuel at 10. The trailing edge of the keel was curved to pull/turn the water flow into the advancing propeller blade for increased thrust. Like stator blades on a jet engine. Opposite curve above and below the propeller shaft of course. When we moved to Alaska I had the Willard AND the Sumnercraft and needed to part w one.

Thanks very much for the geography lessons. My father and my sister were geography majors but I was forestry, art, music and industrial education. Lots of rain in the forecast so I'll get emerged.
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Old 01-12-2013, 08:35 PM   #44
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Not sure this is related to the discussion, except for the corrosion comment.

Steve Dashew uses regular mild steel wafer valves in the exhaust of both genset and engine. He also has a drain valve on his wet exhaust canister to empty it. The result is a wet exhaust system which is bone dry when not in use, which reduces corrosion in the engine.
Apparently the wafer valves are capable of withstanding the mixed air/water exhaust without corrosion.

here is a link to Dashew's exhaust set-up : http://setsail.com/engine-exhaust-li...ary/#more-8901
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Old 01-12-2013, 11:28 PM   #45
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The Eagles exhaust was dry when we bought her, we did not like it so we converted to wet. The new exhaust is raised gravity drained water muffler, which was my basic design. The exhaust pipe is 4" above the water so no exhaust through hull.

We leave the Eagle unlocked as breaking into the boat would be equal, more than what they would take. As for starting the boat that is done in the engine room as I lost the key.
so I hot wired it. I learned when I was a teenage.
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Old 01-13-2013, 07:31 AM   #46
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Luckily, it's only sounded when I turn the key on to start the engine.

Cole Hersey will sell you a marine key start switch with an ACC position .

Hook your "no coolant" siren there.

Also your battery paralleling solenoid .
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Old 01-13-2013, 07:49 AM   #47
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Greetings,
P/F. When you were a teenage what? Just curious...
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Old 01-13-2013, 08:05 AM   #48
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Silly RTF, all you have to do is Google "I was a teenage" and take your choice.
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Old 01-13-2013, 11:04 AM   #49
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Originally Posted by boatpoker View Post
I got mine on amazon.com (a little cheaper)but you can buy direct at aqualarm.net

You simply splice it in line between your raw water intake seacock and your strainer basket, very easy.
I'm planning on installing one of these on each engine..... I have experienced the volume of water that can enter the bilge when a hose comes off. My was after the raw water pump and before the wet manifold..... Like a firehose spraying the bilge....wish I had those then...would have saved an elbow, and about 20 feet of exhaust hose....

Boat poker....not to criticize...but don't you think it would be better it there were two clamps in each side of that gizmo?
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Old 01-13-2013, 12:00 PM   #50
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Greetings,
Mr. Rick B. Oh my! OH MY!!!!!!!!!


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