Hot exhaust materiel and practices

[sailorken]

Hi, when I removed my A4 from "Pretty Lucky", my 1970 Coronado 30 last fall, the sections of pipe that were composed of galvanized were very badly corroded. As a matter of concern, one piece effectively crumbled when I pulled it to disconnect the engine: a real problem if it had stared to leak CO2!

This lead me to believe that galvanized pipe is not good for exhaust. The section that was stainless steel was intact. It happened to be a foot long section of flexible ss that I have yet to find on the market. I may be able to clean it up.

My questions are: is galvanized good? If so, does one need to watch it more carefully?

What other materiels can one use? A friend suggested a length of heavy duty rubber exhaust hose like found on cars.

Does anyone also have a piece of flexible stainless on their exhaust?

What about brass or bronze?

Any other materiels?

Ken

[Don Moyer]

Ken,

Most of the boat builders in the mid to late seventies used black iron pipe, which is (to my understanding) the same as galvanized pipe without the galvanizing. In replacing the hot section between the back of the manifold and the inlet to the water lift muffler, most people use 1-1/4" pipe nipples and elbows. You can use brass or stainless instead of black iron or galvanized pipe if you wish, but at significantly higher cost of course.

One thing is certain: you should never use rubber hose (even rubber exhaust
hose) before the point where the engine cooling water is introduced.

Regards,

Don