Sounds like it might be time for a new boat. My father''s powerboat - a center-console, open something-or-other - was built with foam filling the space under the main deck, essentially filling the bilge and making the thing "unsinkable". They used open-cell foam, however, so it has slowly absorbed the rain and bilgewater that inevitably leaks in, adding hundreds of pounds to the displacement. Your foam may be similar. You''re not just working with the weight of the foam. To really get the foam out will require removing the deck on my dad''s boat as well as yours. This is probably not too cost-effective, though re-attaching the deck more solidly may slow some of the leaks. (There are likely others as well. I know a neighbor''s Laser had a leak in the maststep. That took them a while to figure out.) If you really enjoy working with fiberglass shards, goop, sticking to everything you touch, and have a lot of time, have fun!