[Strider]

I'm no expert but here is what I did on my rebuild. On my deck I used 3/4 inch pressure treated plywood. I sealed it with thinned epoxy resin, installed it and then glassed it over with epoxy resin and glass. The trick to using pressure treated anything in this process is that it must be dry, dry, dry! If you have a moisture meter get it down to 10% or so. If you are going to be bolting anything through this piece of deck then you may want to go with a a/b fir ply. This will have better interior veneers than the p.t. (which is typically a/c) and will have a better back. This is what I used on my transom because I was going to bolt a bracket to it. It will be less likely to crush under pressure from bolts. Marine ply is very expensive (probably not really an issue just for one piece) but my rep at my lumber yard says it's not THAT much different than a/b anymore. Hope this helps.