I have a 12ft aluma craft boat, that has seen a rough life, it sat for 6yrs. with water in it. I need to replace the old transom wood. It had a 2×6 pine on the inside, and the outside was about 3/8s of an inch thick. I need some thoughts of what to use and how thick it should be, I just want to use it once in a while so I don’t need anything special. Thanks. CSW
5/4 hardwood inside, white oak is typically recommended. I just did my FD with hickory since that was all my local hardwood guy had in stock when I needed it. 3/8" Marine plywood on the outside. CDA plywood works also.
The cork backing serves two purposes, one is that it serves as a vibration dampener, and the second is for sealing. If you do it like it came from the factory, you won’t need any sealer anywhere. The cork acts as a gasket and seals around all the bolts. I used craft cork on my boats, and glued it to the boards before installation with aerosol glue. Headliner glue from Oreilly’s, etc.