I am working on a 1985 Rajun Cajun and under the pedestal mount on the rear deck is rotted out from the deck not getting sealed well when the mount was installed. Is there a product that I can use to fill the void created if I were to install another piece of wood under the decking? I cant get the wood cut out from under the deck but I can laminate another piece under it but this will still leave a rot hole between. If I can fill the void it would give the stability back. Thanks.