you are better off staying away from the pine below decks it is not boatbuilding lumber an it will rott out. Try to stay with fur it is stable and will not rot.I used thickened epoxy (bed) with 1708 biaxial tabbed. Some guys go full fiberglass over wood and this is for strength and waterproofing. I used dry PT pine dimensional lumber and didn't need to worry about rot.
That is exactly how to install stringers in a down easter.Fir 2x12's fitted to the curvature of the hull by scribe and routed on top to ease the corners, hot coated underside and set into hull and deck putty which is set with a catalyst just below normal mixing ratios and faired, then hot coat the entire surface and encase in fiberglass, going down onto the hull with at least two layers of structure, shingling the layers, first one 3" - second one 6" from stringer.
Fir 2x12's fitted to the curvature of the hull by scribe and routed on top to ease the corners nd encase in fiberglass, going down onto the hull with at least two layers of structure, shingling the layers, first one 3" - second one 6" from stringer.
I did A LOT of research on pressure treated wood in boats and the this is what it said- it has everything to do with the water content in the wood. If it's dry it will stick using epoxy (polyester is not as strong a bond). I did it and it is solid. I built my boat stringers and sole using very dry pressure treated wood. Some professional boat builders use it in stringers, and the APA (American Plywood Association) did extensive research.
Boat & Ship Manufacturing :: Performance Panels :: APA - The Engineered Wood Association
Boat Builder Central - Howtos
You can make fiberglass stringers without ANY wood and then you don't need to worry about it. I agree with all of you. Money was a factor in my case- composites are the way to go.
Hot Coat - Technical Term
When porous material is used in composite construction, usually a deceased plant medium with varying moisture content, one should first apply resin directly to the surface of that material so that the resin will soak into the material and saturate it so that when one does add a cloth material the porosity doesn't draw the resin away from the reinforcement (fiberglass, carbon fiber, kevlar, the workshirt you were wearing and didn't realize was laying against wet resin, etc). When using foam core it too should be hot coated, not only to fill the pores of the foam but also to go between the kerfs and displace any air so that any water that finds itself in the core cannot spread outside those particular cells - just like balsa core should be installed. Core should be hot coated even if it is going to be bedded into a compound like core-bond.