putting in new floors in 26' Crownline Cabin Cruiser

so, i bought a '93 crownline cabin cruiser. there was about a foot of water in the cabin so i removed all of the rotten wood. i have to put in new stringers, floors and side walls. i really need some info on how to replace the wood so it will not rot. i have never fiberglassed anything and need to know what materials to use. i will be putting in an 8' stringer and several pieces of plywood to lay the floors down over it. also, i need to know what kind of plywood and screws to use and any sealant to put in with the screws to keep water from getting in. i replaced a floor in a bayliner i had one time but never fiberglassed it in and used treated plywood, needless to say, after a few years it started to rot again. thanks everyone.