Wednesday, May 4, 2011

Sojourn’s Exhaust

The Beta’s exhaust comes out on the opposite side of the prop shaft  as the old Volvo and thus my muffler.  I needed a tail pipe that went up about 8 inches, to starboard 9 inches and aft about 17 inches to the muffler. Moving the muffler is possible, but not attractive as it would encroach on storage space in the lazarette. To solve my geometry problem, I designed a tailpipe in Solidworks consisting of a flange, a bent piece of 1-5/8 stainless exhaust tubing, a 1-1/4 pipe nipple, and a 1/2 pipe nipple.  I made the flange myself and had Stan at Stan’s Header’s in Auburn bend the tube. I cut the threaded ends off the 2011-04-23_14-54-29_612nipples and milled a hole in the larger.  I then welded the parts together.  Voila.  After wrapping it with some exhaust lagging, the hole exhaust project cost me $125 and about 2 hours. 

As I’ve said before, I purchased Sojourn as a learning project and am getting my money’s worth.  On that note, I was surprised to find that my old tail pipe actually had evidence of rust, to the point of rot, from the outside than the inside. In fact, if you look closely, there is a hole in it. I have also noticed that every time I2011-04-29_11-39-15_804 started the engine, that the exhaust lagging would steam.  I’ve since learned that the lagging is hygroscopic (has an affinity for water) which causes it to absorb water from the air, of which there is much on a sailboat. Hopefully the stainless will last longer than the carbon steel did.

Other’s who have converted to Beta, will likely recognize that Beta recommends a 2” exhaust for this installation.  I decided to try to save a few hundred dollars and reuse the old exhaust.  If the 1-5/8 doesn’t keep me within allowable back pressure, I’ll have to upsize.  Stay tuned.

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