Hi Jack,
Quite a few years ago I changed the exhaust to the Port side of my boat using the Murray Cressman fitting; also went with the two inch exhaust to reduce back pressure in the exhaust system.I’ve done a few ten day to two week trips since then with no noticable exhaust moustache on the stern. Most of the trips seem always to entail a fair amount of motoring or motor sailing. The fitting seems to be holding up well to the elements.
Tabby 26C #83 W21 motor also Gerard van Boven
I added a 6" x 2" diameter extension last year. It did not solve the problem. This fall I removed heavy gear from the lazarets. This allows a speed of five knots without burying the exhaust resulting in a clean transom as long as I do not go for six knots.
The moustache is not unique to Nonsuches but is prevalent with all designs that locates the exhaust at or near the waterline ( such as the Hughes Columbia sloop 8.7). One day I might get around to raising the exhaust outlet a foot or two, but I can usually find an excuse for better things to do.
John Newell, Mascouche 26C #1
Hi Jack
I have the W13 which has to work much harder when approching hull speed than your W21 I suspect. This year at 2000 to 2200 rpm there is little smoke and I am doing 5 knots in a calm. After several hours of motoring I can clean the moustache if there is one in a few seconds with a sponge. At 2500 rpm the speed is 5.5 and there is noticeable black smoke and the moustache is there. The exhaust is still just above the water. In panic mode in reverse the moustache goes halfway to the bow. I try to avoid motoring fast.
Last year I had a moustache everytime I turned on the engine. I am not sure but I suspect that removing the fuel tank and cleaning out the black diesel and mud that was in there made a difference. The engine seems to run just the same.
I know I have the 2 inch hose from the muffler to the transom as I just replaced it this year. The insurance company made me do it because the existing hose was fuel filler hose and not exhaust hose. Water seems to come out the transom in spurts at idle but IMHO the 2 inch hose works fine.
If we keep this boat, it too will be converted to electric the moment this engine gives us any problems.
Tom