[Wavery]

I am in NO WAY suggesting that this is a reasonable solution for a black water tank. It's more work than most people want to do..... even experienced fiberglassers. There isn't much area to work in there, the temperature is hard to control and the fumes are horrendous.

My original plan was to make a male mold, fiberglass it then move the finished tank into the TM. That would lose me about 1G of storage. My goal was 13G and the only way that I could get that without making the tank uncomfortably high for my 5' tall wife was to build the tank in place. Again, I don't recommend it.

This tank is 4 layers of F/G (1st coat mat, 2nd coat woven roving, 3rd coat mat, 4th coat biaxial cloth) 2 coats gelcoat on 1/4" thick plywood frame. It holds 14G but 13.5 is reasonably full.