No knocking here. Just stating what I've heard from many that have boated in both areas. Ratings aren't perfect, nor easy to correlate between rivers. But in general this is what I've been told, and such information is useful for this discussion. IF he was really boating Class V, I'd start calling him names for a stupid idea. In the interest of safety you know
I can't even imagine how a wood floor would perform anything other than horrible (except maybe in Class II/III). I expect it would be way worse than a raft floor (which moves). Why have nice inflatable tubes and then wood on down by the water? I'm at a loss to explain what I think about this, language is just too limiting. Get something that drains, trampoline, mesh, polymax, even Scott's metal sounds functional but painful, heavy, and maybe damaging to drysuits?
Or as Josh says, bag the floor. It's easier to launch/land a boat, easier to get back in when you flip/swim, is lighter, lets you see the line better, and provides absolutely no obstruction to the water optimizing the tendency for cats to be like "hot knives through butter". Especially if you are talking about going up to Class IV (to us), having nothing in the way makes the cat perform ideal.