Couple things.......

Fuel tanks in a different location will probably affect the CG of the boat and change it's handling characteristics. Replacing the sand bags with fuel will provide similiar function but the fuel will weigh 247lbs and as the fuel burns the boat may handle differently. If at all possible I would place them in the factory location. What if you reinforced the holes with several extra layers of fiberglass mat and resin. Then have extra sturdy tanks built and foam them in. I would then build new floor sections with some cross bracing built into the floor sections and the glass those into place! IMO you would be fine!

I guess my 2 cents worth!

Good luck
Jim

There is a thread by OFFSHORE GINGER , on serious offshore , speedwake , scream and fly titled Skater 32 and it shows the process that is being done to do the repair on Skater gas tanks along with other things that have been done to the boat . I might mention that there is a long list of materials involved in the overall process in doing the repair on the tanks and you just might want to check them out .

ATL makes Rotor Molded tanks with baffles along with Bladders , and Aluminum .

the bad thing is the old tank is at an angle and the space probably wouldnt hold but around 12 gallons in the middle section. look at the pics and there is a "stringer" that goes from the back to the front thats about 4" tall.(see pics)

Just curious how many gallons did the tanks really hold ?

I think you may be surprised how much fuel it could hold. Give me the following dimensions and I will calculate the gallons

Height from the hull to the floor on the outside stringer (shallow side)
Height from the hull to the floor on the inside stringer (deep side)
Width from outside to inside stringer
Length of hole

And might i mention needless to say those tanks can be repaired .