deck reconstruction

[chrisvazquez1]

Im a new member and just recently purchased my second seacraft. I bought a 20' 1984 from a guy down in ft pierce. I recently tore out the old soggy deck and left about 2 inches lip to refit the new deck. My question pertains to the plywood i recently purchased. I bought 1/2" ac exterior grade plywood although the old wood looks like 3/4".Is that a big deal? considering I plan to glass the boards before setting them in place. Does this sound like a go? or no? also any info on what fiberglass to use for the deck would be appreciated: chopped mat, woven roven, biaxil??