Quote:
Originally Posted by Husker525
I looked and found that someone had attempted to MIG weld several seams near the transom. It does not look like they did a good job. There are cracks around every bird poop weld that was made.
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Did they weld seams or cracks? While welding is ok on plate construction hulls, it is not a good idea on formed sheet 5086 alloy riveted hulls. Superstructure components in the boat that uses weldments is usually 6061. Either alloy can be either MIG or TIG welded. Pulse MIG is the preferred, that is what is used at the factory for welded hulls or superstructures. However, not after it has been work hardened. It will just crack alongside the welds.
Riveted boats are built with a sealer in the seams. The reason they start to leak is because the sealer gave out. So re-seal it, don't weld on it unless it is superstructure parts. And even then welding stress cracks is rarely successful after the metal has work hardened. Repair cracks in bulkheads or superstructure with plate or angle and bucked rivet patch.
Re-sealing is done from the inside with Marine-Tex epoxy. Like the older two-piece alumacraft hulls, the two pieces of the hull are joined at the keel. Those will normally start to leak after 30 years. I've completely stripped the boat down to the bare hull, fill the keel with Marine-Tex and that will fix it. You can buy the stuff in quart cans.
The problem you have now is that somebody welded on a formed sheet hull without knowing what they were doing. Those cracks alongside the welds are not going to stop. It could've been re-sealed and not a problem. And you can patch it with Marine-Tex. But those cracks are going to "work" and keep traveling. So stop drill the cracks to relieve stress, then seal it with Marine-Tex for a "patch job".
The best option if you want to fix it right is to drill the rivets and replace the sheets with new where it's been welded. If the sheets have compound bends done in a die you have problem unless you have a full metal shop because you're probably not going to get replacement sheets to fit tight. In that case, even after bucking rivets, they're going to "work" and start to leak again.
I'd have to see the hull before I'd make a decision on how to fix it, and I've done a few of 'em, mostly older Alumacraft's.