Fixing severe pitting and holes on alu boat

So I got my first boat, a aluminium one, and now after one season, its leaking. I tore up the floor to have a look and there is deep pitting and one smal hole in the “grooves” at the bottom of the hull. The brown hole in the upper middle of the picture is about 2 mm.

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Alot of posts I read says to weld it but I dont have a welder and it seems to be a big risk of creating a bigger whole. I was first thinking of filling more of less the entire groove withe epoxy but then I stumbled on to soldering that seems to be a more gentle option than welding. So Im leaning towards soldering.

What do you think, epoxy, aluminium epoxy stick or soldering?

There will be a different thread on why it's corroding.