I have to replace the deck, plywood.
I have heard from some nothing like marine plywood, from others treated plywood. whitch one do you think???

/ al

Is your floor plywood with a carpet on top? Best bet would be marine plywood, then treated plywood - go for the quality stuff too. Most of what I've also seen is that you need to apply a resin finish on both sides and the ends. This will prevent if from prematurely rotting... Intersting on my old boat (Sea Ray), it had a plywood deck with acarpet attecjed - it was just getting spongy after 5 years. Not bad, just barely perceptible. Would not have happened if it were properly sealed...