[Caymanboy]

I cut the floor right done the middle or little to the outboard of the stringers, finished the edges, fastened the deck to the stringer, applied crossed butt joints at the forward and aft part of the hatch, made supports accross the keel for the tank, had the tank made with taps on top, screwed thru the tabs into the stringer to fasten the tank. Glassed the edges of the cut out piece and used that as the hatch.