Exhaust System

[Andre Michel]

the galvanized exhaust pipe on my 1972 Catalina 27 with an atomic 4 was corroded so badly that it split in two while i was motorsailing one evening i was taking on water until i figured out what happened and plugged the pipe meanwhile i proceded to consrtuct a new exhaust system to the exact size as the old one the engine seems to have suffered no damage no water entered the engine however the loop in the pipe is about 3 inches short of the engine compartment top should it rise as far as possible to eliminate the possibility of water making its way back through the system and entering the engine when not on ? should there be a rubber flap on the exhaust through hull to prevent back flow ? thank you

 

[Rob Rich]

Check the SailNet A-4 list...

There is a great list serv at sail net. You can ask this question and get answers from a bunch of guys that seem to work on their engines more than they sail! They will be able to give you precise answer.As far as a flapper goes, yes, you can install one and you should have both a screw and a fitting on your exhaust outlet for the flap to attach to.Your loop sounds like it is at a good height, similar to mine, but I am only going off the top of my head. Remember, you dont want to put it too close to the top of the engine compartment since it gets so hot. Some folks have insulated the roof to reflect heat and minimize heat damage, but I have not actually seen one of these.Best of luck, and let us know what you find out!Rob

 

[Tom Soko]

What about AquaLift Muffler?

The height of the loop in the exhaust pipe sounds good, but you do not mention an aqualift muffler. There absolutely should be one back there. It looks like a fiberglass box about 1 cubic foot in size. It is the only way to make sure you won't get any water back into the engine. I know from experience. My '75 C-30 didn't have one, and I ended up having to rebuild the A-4 because of water backing up into the engine. They're available directly from Catalina, and not too hard to install. Good Luck.