Water. Hollow wood surfboard. Keep the water out, no problem. Let the water in, big problem. My 6-7 fish got water in it, just a little and over a period of weeks the planks swelled. The skins were kind of corrugated, but it was not a problem and it surfed fine. I guess the water made with wood swell and that opened up a seam near the nose. A recent surf with my son on the fish yielded about half a gallon of water in the fish after the surf! NO! So I stripped the glass, which was pretty easy.
Here the skin is stripped and I've cut out a two access hole for drying and reguling the bottom planks. I used an inexpensive subfloor adhesive to attach the ribs and skins. Either the glue is not really waterproof, or the movement of the skins was strong enough to break the bond. Also, this is the only board I've finished with polyester resin. I now believe strongly that poly is too brittle to be used over wood. None of my epoxy finished boards have shown any problems like this. Maybe everybody else know this but I just figured it out!
After I routered out the top deck, I was able to just pull the decking off with my hand...not a good testament to the adhesive. So the plan is to let this thing dry out and then reglue the bottom skin to the ribs using...??? I don't know! Maybe 3M 5200. That is supposed to be the best thing, so I'll try it. Then I'll cut in a dutchman on the deck and reglass with 6 ounce cloth and epoxy. I've used 4 ounce on my boards so far, and after stripping it off, man, is it thin! Maybe 6 ounce would be better. If I were a good glasser, I'd double wrap the rails, as that is where the critical glue bonds are, but that sounds like a lot of work.
Here is my fix to reglue the bottom to the frame. I've added 1/4" square strips glued to both the frame and the bottom on each side of the rib. It was not realistic to get 5200 between the ribs and the skins and I used Titebond III. This will give a greater gluing area and reduce the stresses.
Here is a doubler along the top of the rib so I can reglue the planks adjacent to the opening.