Our old Moore came with 30 inch light fiberglass decks, mildly peaked, and with a substantial lip at the back end to divert water that might slosh down the deck.
Quarter inch ply sounds kind of thick, unless you need to stand on it. But if that's what you've got....
Kaz, the Millbrook canoe builder, values very light weight, and his decks are laid up of 2 ply FG or Kevlar. They are screwed down to the ash gunwales, and to a short ash cross thwart at the back. Once installed, they are probably strong enough to stand on.
As for other materials folks might consider, I was attracted to the corrugated plastic the Post Office uses to make mail bins. Fairly light and stiff. Probably one of the lightest solutions is stiff closed cell foam sandwiched in Kevlar, which is seen on the decks of some slalom boats. But that's a custom deal. I would be unsure where to get the foam, and the sandwich dents easily.
2-3 Canoe/Kayak Trailer
Overstock Outlet Foods
Pull-Up Strap Handle Kit
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