I got a old boat recently, for free.  Unfortunately it was in pretty rough shape, and I'm looking for advice.  It's a 12 ft. by 44 in. fiberglass v-hull with several patched spots that appear to be ok.  There was also a foot long crack on the bow that i patched along with two smaller cracks towards the back of the boat.  I knocked out the bench seats since they were cracked and the foam under them was in bad shape.  The problem is, now the boat feels very flimsy feeling, the sides feel like they're gonna fold in. So the question is what now, build a new bench seat to try and stabilize the sides.  Thanks if anyone responds.

The bench seat was acting as a bulkhead as far as lateral rigidity in that hull.  You need to get something back in there to help with cross support across the beam.  You're asking for trouble if you don't.

thanks, any advice on attaching a wooden bench seat structure, sealed with resin of couse, to the boat with out damaging the fiberglass or causing cracks when i sit on it, or puting a thin wooden floor on the bottom to flatten the standing surface.  I know they're are a ton of posts on hear about decks on aluminum boats, but i'm concerned about the fiberglasses flexibily, I don't want a standing deck just a floor to maybe put carpet on.  I also don't want to take the boat out, stand up and fall through the bottom, you probably already knew that.

If you don't want the bench, you could try mounting a few gussets from the floor to the walls at 18 inch intervals. I would make them 12"x12" and you could take out alot of the 'meat' by cutting them with smooth curves. I'm in the process of building a 14 ft. flat-bottom, and that's what I'm doing to avoid a center bench.