You're welcome, just stop blaming the twins because you want a swing set to play with.

I flushed my gas tanks out with water, let them sit upside down in the sun for a few hours, and then sprayed a sh!tload of WD-40 in there. My tanks were steel and I'm sure the WD-40 was a waiste of time and resources.

I wouldn't try to seal the gas gauge sending unit with silicone. New sending unit's come with a gasket, made of rubber if I remember correctly. Get some gasket material from Kragen or where ever and put a couple of paper gaskets in there, unless you have some rubber laying around, I dunno, say an old bicycle inner tube?

I can't see any cracks in your pictures and by the size of that off road tire in the first pic
how big is your boat? 