Two Lucky Fish has a Wallas stove/heater, which is a pretty handy gadget. It burns diesel or kerosene, and all exhaust is vented overboard. In fact, I used it today both to heat the boat and cook lunch. Cozy!

Anyway, this spring I discovered a problem with my stove installation. Not with the stove itself; it’s working fine. Perhaps you remember this photo from my recent haulout:

The Wallas exhaust vent is on the right. Rust stains were only part of the problem. Even worse was that water would enter the cabin through the through-hull. Not all the time; the ingress occurred only in choppy weather when waves would strike from the starboard side, where the through-hull is. Water would be forced into the exhaust hose, where it should drain right back out the way it came in. But it wasn’t all escaping; some was leaking into the cabin. And rust-staining the hull, inside and out, in the process!

Here’s what I encountered when I started in on this project. There was a lot of rust, but the flexible exhaust hose looked fine, and the through-hull didn’t appear to be the source of the problem either.

A bit more disassembly revealed more rust.

Near as I can figure, all the rust-staining in the two photos above is the result of this hose clamp, which wouldn’t even disengage in the conventional way. It just broke when I tried to unscrew it.

Doug McElroy of Scan Marine confirmed my diagnosis and helped me identify the solution. I took it all apart, cleaned up the parts, and put it back together again with fancy Permatex Ultra Copper high-temperature RTV silicone from the auto parts store. You don’t have to use this copper-colored variety; any of the high-temp RTV silicones will work, and it’s available in black and white.

In the process, I replaced the sock and the hose clamps with new ones provided by Scan Marine. The new hose clamps look much more robust, and are obviously made of high-quality stainless steel.

There were no big surprises in this operation, and the photos illustrate the process pretty well.

Here’s a view looking up at the underside of the Wallas stove, showing the exhaust tubing. It also shows that I have some more rust stains to clean up in there!

By the way, if you want to learn more about the Wallas products, stop by the Scan Marine shop on Lake Union in Seattle, or catch these folks at one of the boat shows.