Sunday, April 13, 2008
The exhaust is my biggest pleasure as an "Alaskan engineer". You should have seen Annie and me pouring water down hose to figure the volume to size a water lift muffler. The original system was a very hot 1 1/2" pipe that went up the shaft alley 28' to the lazerette where it went into a rusted out muffler where water was injected. The original system was supposed to be double walled and wrapped. I got a new exhaust elbow that had a 5/8" pipe welded at an angle away from the exhaust manifold. I was advised to use 2" U.S. Coast Guard approved "blue" stripe hose @ $4.00 per ft.. I bought 30' and just had enough to finish the job. We got a 1 gallon, ( yes, that's right) water lift muffler and placed it next to the shaft coupling on the starboard side. Ran rubber hose to it from the exhaust extension. Ran 8' of the same 2" hose to a 2" bronze vented loop at the top of the port hanging locker. From there we ran the hose along the port side at an ever decreasing angle to the lazerette where I installed a 2" ball valve to stop any water entering system if overloading or following seas pushing water into boat when sailing. When we started the engine the first time I ran it only a short time and Annie shut it down, I quickly pulled the hose from the muffler to see the volume of water left in it and weather the level had risen to the exhaust manifold. I was pleasantly surprised to see about 1/2 gal. of water left. The vented loop let the water run out the stern instead of filling a much larger muffler. It worked and has been working well for 7 years! We learned the exhaust hose was only about 1/4 full when running. I feel the Achilles heel of a Columbia 50 is its own designed engine so low in the boat. Many have been "watered" by bad exhaust systems or being "poop ed" by a possible boarding sea in my view. I hope never to fill my cockpit with water but it does happen.