[BarryB]

The photo you attached shows a screw not all the way in with the head flush. Did you leave the screw that way or did you tighten it down all the way?

On some other threads, some owners mention a "plastic welding machine" ($30.00) from harbor tools. I purchased one and it looks like I'll have fun with it. Basically, it looks like a large soldering iron with a hole in the tip. You attach the other end to a compressor with the attached hose and pressure regulator. Air is pumped through the tip at high temp. The plastics melts just like welding. If you were to drain the tank and air it out for a few days, I bet you may be able to weld it, or bring the boat to a marine shop to see if they could fix the tank.

This is the same welder owners use to fix holes and do other repairs on the boat. You can purchase the welding rod from Merrit Marine. Ask NCAngler about that. He is the "Master Yoda".