I have a older river craft boat. It's justice a little over 4 feet wide. It's almost identical to the Randall craft, Collins and Kennedy craft boats built up here in the Florida panhandle. I don't have a good source of marine grade plywood. I've done some research and found that good exterior grade is close to the same quality. I will be encapsulating it in fiberglass and epoxy resin. If the boat lasts another 10 years it more than I could ask for. Any reason not to use the exterior grade for this ?
It'll be fine. Just get a good piece of dry wood. Seal all penetrations with epoxy plugs and sealant around the screws/bolts. I'd say it would last ten plus.
If your willing to spend about $70 on materials I would make it out of 1" Divynal cell core. It will never rot and will support your motor. I made mine out of 1 1/2" and it supports a 40HP Tohatsu.
