Oak is heavy, and not quite as rot resistant as you might like but it
certainly is strong enough. Be careful not to increase "Old Maude's"
weight too much.

Good points, and taken.I'm going to take a piece of whats in there to
him, to see just what IS in there.I'm NOT a wood identifier.
Old Maude..as I call her (not the boats name) is a 67 CC Corsair, 20
footer. It probably weighs a ton already, but the floor support
structure is wet and punky in spots, and needs to go. I'll install new
3/4 inch Marine plywood floor after this is done.
Whats a good wood to use? Ideas?????

S.