Having tried most things over the past few years I can say with confidence that glass mat and epoxy is NOT the way forward here. THe best answer is side tanks.This stiffens the floor and is cheaper than bags. 1 2440x1220 (8x4) sheet of 4mm will do the job Robbins at bristol can supply you want "elite" you will also need two ends and at least two intermediates , your freindly local boat builder is usually snided out with offcuts for this job again 4 or 5 mm is plenty fit these with cedar 15mm sq front and top for glue area and one cedar strip 15 sq set in along the inside top before fitting the ply. sont forget to put reinforcing in for fairleads. Fit the inside first with a substancial epoxy fillet on the inside of the tank, to prevent the crew kicking through every time you tack,and a nice tidy one on the outside then glue the top on after the epoxy cures. We have of course primed all the inside surfaces before the top goes on.
While you are doing this I think it is usually worth ripping out the floor batterns and replacing them. The old Fairey boats used some form of flimsy stuff that could have been pitch pine but was onlt about 6mm thick and flexible. Tear em out and I replace with two per side 30x12 glued down douglas fir or merante is what I use depending on what I have.
Good luck I have done 6 now and enjoyed doing them all.
Sam
