If similar to C22----
Mike: My 1974 C22 had a cockpit floor problem a couple of years back. It was a little soft and the resin/fiberglass developed several small cracks which eventually allowed rainwater to seep into the plywood beneath the fiberglass. This was evident by water bubling back up when I sponged it off the floor, and walked around the cracks a bit. My fix was to first dry out the wood completely over winter, then I tried to get a West System resin to penetrate the cracks and seal them. It did for a month or so, then leaked again. So then I waited until the wood was dry again and then got into the side compartment where I could see and get my hands into the area beneath the cockpit floor. What I found was that the plywood had been a poor grade and had a large knot showing which had made for a very weak spot. So using a waterproof glue, I glued from the bottom a good piece of 3/8 in. plywood under the original. To hold in place while the glue was drying, I had to wedge a bunch of short pieces of wood between the new piece and the inside bottom of the hull. Afterward, I removed the wedges. Then I fiberglassed over the cracks from the topside of the cockpit and refinished the floor, using a fine sand grit in a paint to keep footing from being slippery. Looks pretty good and is definitely functional.RK