I used to work with fiberglass at a previous job. We used aluminum honeycomb board as a replacement for plywood. It is light, strong and very expensive. I don't know how well it will work for stringers but it would definitely be worth looking into.
Take a look at my 1976 SRV240 weekender. I think yours may be a Sundancer. Mine has the OMC outdrive with the 351 ford engine. Click on my name and look at the pictures in my profile. I have the original OMC owners manual. I am not sure there was a manual for the boat.
Nice Boat with great lines. I don't envy you on the rub out of the hull. I am working on mine now and its killing me. These old boats are easy to work on and usually paid for.
Anyone know what the max rpm would be for a OMC 351 235 hp engine. I think it was geared too low as the engine would only go to about 3200 rpm and seem to bog down. I have recently changed the outdrive and it has different gears. Now I can get well above 4000 rpm without going to WOT. I...
On mine there is a bilge pump under the step going down into the cabin that drains out a side drain. Seems like it always leave a little water down there.
fyi,
I would say get with the surveyor. If he says it can be done without pulling the motors he should know. Everyone else has not seen the damage. It could have been cause by a small though hole leaking. We are just speculating and the surveyor has the facts.
Good Luck!