The main problem that I've seen in alum. consted boats is stress areas. Right in corners where the boats twist, is where cracks seem to form, usually right next to a weld. Stanchons welded to a
deck is a common place. And some places along where the
deck meets the
hull.
Personally, If I were to build with alum. I'd do a strong frame with rounded corners where ever possible.
One thing you have to remember, alum. shrinks after a weld. When one welds the
hull skin to a frame, it should only be skip welded. A solid weld will suck the skin in all the way down the frame and it'll show on the out side.
I'd recommend crawling around inside a few alum. boats, young and old, to see the do's and don't's about construction. You'll see what happens with different procedures.
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