five sheets of marine 3/4 will cost you the price of a boat! go with A/C grade 3/4 ply and use resin on it
Do yourself an immense favor and log on to Amazon or whoever you like to get books from and get "Runabout Renovation" by Jim Anderson. Tells ya all about what woods, what resins, what sealants, fasteners, the works. ten to twenty bucks WELL SPENT, a bargain for fifty bucks!