Originally Posted by Stuckntx
Ive used seacast on a smaller hp boat and it worked fine. Went in carefully from the top with an electric chainsaw and dug the old wood out.
Im know its strong enough for your application but getting all of the shit wood out will be difficult. You could take part of the inner skin off clean out the rotten wood reglass it back in place and then fill with seacast. Or better yet take the back skin off since the inside is tied into the stringers and that where all the strength is on an IO. Again clear the shit wood and pour. Or do it right and use marine ply. Epoxy to the inside skin, epoxy outer skin on, reglass, fair and paint.
I don't know if I'd call fixing it with marine ply wood "right" these days. It would be cheaper, but will rot again.
IME wood has no place on a boat anymore except for cost.
I did a transom on a trihull 10+ years ago with plywood. Pain in the ass, but doable because I was able to pull the deck cap, not an option here. In hindsight I should have done a pour in on it and gone boating sooner.