Redoing the cabin on my cig flatdeck. I don't want to reuse the wood panels as they kind of have a little funk about them plus I don't have the time to scape them clean.
So question is what's the best material for and if it's still plywood what is the thinnest that can be used without any deflecting or warping?
What I took out was almost 1/2 inch and heavy as hell!!

I used just 1/4" underlayment inside my cabin walls however I didn't have much more than 18" span the way it worked out. I cut each piece to fit and rolled two thinned coats of resin on each side. I used it for the headliner panels as well. Extremely light and inexpensive while easy to work with. #8 screws with finishing caps to fasten. The 1/2" would definitely ad some strength if you think it's necessary. My boat is stored inside and pretty much a weekend runner and was looking to cut weight where I could.

There was a thread about a year ago in regards to some material that looked great and was extremely mold resistant. Pretty cool product. A quick search may find it. If I recall it was a little on the pricey side but I guess it comes down to the application.

Good luck
John

On my SCARAB the head liner was nothing more than stretched vinyl. There was a center board that was attached to the roof and then a board at each side and the vinyl was stretched between. Very clean look.

When I did mine on the flat deck it was all 1/4 plywood. You need that flex to get the headliner back though the cuddy door . 1/4 inch plywood 1/2 inch foam and then the vinyl. That the set up that worked on mine