A25 exhaust system

[kerrye]

Check valve arrived today. It's nothing more than a fiberglass case with a rubber flap inside. It's 8" long. Lots of variation of the description of it on different web sites. One said it was 17" long. It should work. It's not as positive as a ball valve but it takes no effort for it to work.

[kerrye]

Check valve installed. A little insurance to stop water from entering the engine or sinking the boat.

[WillieC]

I am curious about how you keep an eye on the check valve. You are mainly on freshwater, which has its share of problems, but on the salt, things tend to gunk up quickly. I like the idea and the cost and relatively simple installation, but... I guess if I am counting on this to prevent catastrophe, I need to know it's working. Then again, right now and for the past 43 years, my boat has NOTHING like this.

[kerrye]

No way to keep an eye on it apart from disassembly. I'm mostly counting on it to stop engine water intrusion and to slow down water intrusion if I had a failed exhaust system like what happened to me recently. Since there is probably water in the exhaust all the time the boat is in the water, there could be marine growth accumulation inside the hoses and in the check valve although there were no signs of it in my hose.

[smacksman]

Not too much to stuff a rag in the hull fitting and remove it for inspection now and again.
Drop it in some hydrochloric acid to clean. Builders merchants sell it by the 2.5 gal in the UK for cleaning cement stains off brickwork and slabs. There will be an equivalent in the US.

[kerrye]

Splashed the boat today and I can confirm there is no need for a muffler on an A25, or at least one with a Westerbeke 42. I could hear no decibel difference with or without the muffler. So I say, leave it off and reduce your backpressure.

[smacksman]

When space rockets take off they dump thousands of gallons of water on the launch site mainly to kill the sound, I read. The water injection on a yacht exhaust cools it but also quiets it.
A reservoir to collect the water on cranking and shutdown is a desirable addition.
Glad to read you are sailing again. Fair winds.
Roger

[kerrye]

In most cases, collecting that water is important. On an A25, with the original exhaust design, it doesn't matter since any accumulated water will run out the exhaust thru hull before it gets high enough to enter the engine.

[WillieC]

I WAS right! Albins in space!

[sail149]

MA Based Westerbeke Corp. have a great engine installation manual on line, updated June 2016
http://www.westerbeke.com/installation% ... manual.pdf
Full of really good information including how to check back pressure ( if that bothers you)
Page 14 starts on exhaust installation of below waterline engines!

[Beta Don]

I am curious about how you keep an eye on the check valve. You are mainly on freshwater, which has its share of problems, but on the salt, things tend to gunk up quickly. I like the idea and the cost and relatively simple installation, but... I guess if I am counting on this to prevent catastrophe, I need to know it's working.

I agree - I would worry about it if it's really needed to keep water out of the engine. I've never seen a check valve in the exhaust system on any boat. Over time, it *will* gunk up and refuse to close completely. A better idea is the arrangement shown in the Westerbeke manual where you don't need a check valve to keep water from back flowing into the engine. If you elect to keep the valve there, I would remove it and thoroughly clean it at least once every season

Don

[WillieC]

Thank you, Don. The tricky part in the A25 is making it all fit, without changing the boat drastically. Somewhere in these threads I posted a few pics showing where the waterline actually is in relation to the exhaust manifold, elbow and muffler. My tendency is to let sleeping dogs lie, until I read about Kerry's Really Bad Horrible Day. Then DesertAlbin736's ripped off dinghy in heavy following seas. Surely the boat interior could be adjusted to do what Albin should have done originally. Will ponder these things while I contemplate swapping my engines. Spare is almost ready to run, on the shop floor. Will post separately if successful. Only BetaDon has the integrity and guts to air his failings. For the benefit of ALL of us, I might add. Thanks again, Don.

[DesertAlbin736]

WillieC: Am anxious to see your engine project. We're on the back side of our cruise and ought to be back in Bellingham for haulout by the end of the month. Hopefully will be able to swing by on the way home.

Just pulled into Silva Bay on Gabriola Island after a short run down the East side of the island from Nanaimo. This avoided running Dodd Narrows since afternoon slack wasn't until just a few minutes ago. Max.flood current in Dodd Narrows this morning was 7.8 knots & max ebb current was 5.8 knots.

Thankfully we haven't had problems with the exhaust system, but we did have to deal with that leaking fuel line thing at the start of the cruise,

[smacksman]

I've just spent three weeks sailing the UK south coast with friends in an Albin Vega 27 sailboat. With three big men in the cockpit the exhaust outlet was permanently under water and the back pressure didn't seem to worry the Yanmar 2GM12 at all.
Roger

[BCboater]

I just finished installing a Beta 30 engine in my Albin 25. The Beta Marine manual says that the point where the water from the heat exchanger enters the wet exhaust system must be 15 cm above the waterline to avoid the potential for a siphon to occur from the raw water through-hull through the heat exchanger, eventually backflooding into the engine. In my installation I found that the waterline was right at the same level as the water injection into the wet exhaust.

The simplest solution would have been to instal the “high rise exhaust”fitting that Beta sells, but there was not room under the Albin engine cowling. The next simplest solution would have been to tap into the water hose from the heat exchanger at its highest point and run a small tube up to vent to outside the hull and break any possible siphon. Unfortunately this was not possible due to the Albin engine cowling hinging upward.

The solution I adopted was to route the return hose from the heat exchanger down and out of the engine compartment to a high-rise loop in the port side locker with a Vetus anti-siphon loop at the top of it. It then goes back down and into the engine compartment, up to a “u-shaped” stainless steel fitting I had fabricated (which just clears the top of the engine cowling) and into the raw water injection to the wet exhaust.

It's a little convoluted, but provides a completely passive system, i.e. I don't have to remember to plug, switch, or otherwise change anything when putting the boat away.

Hopefully the pictures will illustrate the system.