Replacing Soft floor on Flats Boat

[bronconut]

I would appreciate your knowledge in helping me accomplish this job with satisfaction. First off, I have a 20 foot flats boat, a scooter (no sides). I removed the floor and am planning on replacing the stringers as well.
1. If I use 1/2" marine plywood do I need to seal the bottomside (underneath) with resin/epoxy?

2. If I used CDX and seal the underside as well, will it last 5-10 years?

3. Being that it is a flats/shallow water boat how many layers of fiberglass mat would be suffice. I was thinking 2 layers of 1.5 oz. for the floor..

4. What type of wood could I use for the 1x2" stringers. I was thinking pressure treated 1x4 pine, split down the middle....

5. Lastly, if I used polyester resin to coat the underneath of the floor what could I expect?

Thanks in Advance

[gonzo]

There is a lot of talk on the difference between plywood and the durability. CDX is made of pine, which doesn't adhers as well as fir or mahogany. However the glue is the same but set at lesser pressure. Also CDX has more voids and knots. If it is encapsul lated, it will last forever. After all, balsa wood cores, which have much less rot resistant, also last indefinetly unless there is water intrusion. I have built cheap skiffs with CDX, that left outside and with only one coat of paint, lived for about four years.

[bronconut]

Thanks Gonzo for the input. Do you think that 2 of the 1.5 oz fiberglass mat w/poly is okay?

[gonzo]

1.50z mat would be adequate. Make sure you coat the under side of the plywood.