Discovery of water in exhaust system

[Chuckatuck Ray]

Yesterday a diesel mechanic I hired helped me remove the 6 inch dia. By 6 inch long exhaust hose that connects to the wet elbow on my Cummins 6BTA5.9 , 330 HP diesel engine. My boat is an Albin 28TE. The hose developed a crack in it and was leaking exhaust fumes into the engine compartment. It took a few hours just to remove the wet exhaust elbow. The bolts were frozen and two of the heads rounded off while trying to remove them. We eventually were able to remove all four bolts. Once the hose that connects to the wet exhaust elbow was disconnected, I was surprised to find water standing in the exhaust pipe just a couple of feet from the exhaust elbow! We attempted to pump out the water but that did not work. The exhaust pipe just continued to fill with sea water. Is this normal or do I have some sort of muffler failure? I would have thought that the exhaust system on a boat would be designed with baffles in the muffler or a check valve of some sort to prevent sea water from standing in the entire length of exhaust piping. Anyone have any insight into the design of the exhaust system on the Albin 28TE? I’m going to have the boat hauled this week so that I can replace the other two hoses on the exhaust and if there is something else wrong with the system I could have it looked at while I’m out of the water.

Best regards, Ray

[Russell]

Ray, I think that is pretty much the way wet exhausts work. This is why it is critical to have the elbow elevated above the exhaust system. If it is not high enough water can return into the combustion chamber through the exhaust valves. The water in the muffler helps quiet the exhaust and if you watch at idle you will see the cooling water build up in the muffler and then be blown out in a gulp. The tip of the exhaust is slightly below the water line so with the engine off water can still lay in the bottom of the exhaust lines.
Boating out of Norfolk for 25 years I always admired the work boats with dry stacks and keel coolers. I guess that is too expensive for recreational boats.

[Chuckatuck Ray]

Russ

Thanks for your reply. I think you are right-on about how the exhaust system is designed. I'll know for sure soon. I am moving my boat to Bluewater Marina in Hampton today and it is scheduled to be hauled tomorrow.

Thans again for the reply.
Ray

[marko]

Ray: I have the same Cummins engines on my 36ET. The last time I had it hauled I photographed inside the black hole of the exhaust tube and was surprised later while looking at the photos to see something in there about 4 ft back inside. It appeared to be a recessed back flow flapper (could not see a hinge though) but it could have been a baffle in the muffler. That photo is on another computer and I'll see if I can locate it to post. When you're hauled, you might try the same photo &/or peer in there with a flash light. Would be curious to know what you can see. Also, I have had one exhaust elbow replaced while in the water and did not have standing water up near the open tube end, a good thing. As a precaution, I did fit in a temporary stop plug: a small plastic bucket with duct tape and clamps tightened to hold in place. Always wondered why most (all?) Albins don't have the exterior transom mounted backflow flaps that are seen on many other boats. Mark

[Chuckatuck Ray]

Mark,
Thanks for informing me of your discovery. My boat is currently at a yard in Hampton waiting for the mechanics there to install the new exhaust hoses. I'll ask them to look inside of the muffler and let me know what they find.
I'll let you and the others know what they discover.
Best regards,
Ray

[marko]

Ray:
This is the photo I mentioned. Just standing outside looking into the exhaust, I saw blackness and the krill (I think that's what was in there) left in the end of the exhaust tube. So I took a photo with flash and saw either a backflow preventing flapper or a baffle in the muffler. It's the same on both sides. It appeared to be back at the exhaust tube - muffler intersection. I did clean out the tubes, but never investigated the muffler further. I'm curious now. We'll see what you find out.
Mark

[Chuckatuck Ray]

Mark,
Thanks for sending the picture.
Ray