I have a frameless wooden driftboat that I am replacing the transom. I was considering replacing the water damaged plywood transom with a transom made from flatsawn white oak. Should I stick to marine plywood or would the white oak hold up? What thickness would be recommended?
Jeff, if you use the flat sawn white oak will you use multiple pieces and if so how will you join them? In wooden sailboats and motorboats there are a couple of issues I often see mentioned. White oak has a reputation of not working with epoxy well over the long term. Secondly it will have a propensity to swell and shrink as it is gotten wet and dry. You may find that the joints open up and cause leaks. You haven't suggested how often you will be using your boat, how you will store it, why the plywood was damaged. Those factors might make a more dimensionally stable material like plywood more suitable. Epoxy it in, put a finish on it and keep the finish in good shape and you should be okay.
Jeff: Rick is right. Since it is a S&G you don't have a frame around the transom and probably need a 3/4" or 1" section of Marine grade PW. Rather than pay for a sheet of thick stuff you can laminate several layers of thinner(less expensive) PW and get the thickness you require. I have done this on several boats and it works well.