Re: do old aluminum boats REQUIRE seam sealer?
My former neighbor in Ohio had a ~14ft jon boat given to him with a 2.2 motor... we took it out for a cat fishing tournament when we realized it was slowly taking on water. We ended up bailing it out the rest of the night before we got in (and finished dead last)...
During the week, I took the boat and propped it level on wooden blocks and filled it with water. What I discovered was that the seam where the hull connects to the transom had tiny leaks (almost like the leaks were sweating).
The boat had been dragged so often that the friction abraded through the metal. I emptied the water and propped the boat in my garage with the bow tied up to a ceiling joist (about a 30 degree angle). I mixed up a quart of epoxy and filled the inside of seam by allowing the epoxy to "collect" at the bottom corner. As it cured, I pulled it up the sides (where the transom meets the hull) as well to ensure no leaks.
Next time out, the boat was completely dry.