I have owned an old glass over
plywood vessel, that got two soft spots on the sides above the
water line that I had to cut out and replace, the glass itself had de-laminated from the
hull of the vessel, this was with polyester resin. I have repaired plank vessels that had been encapsulated with
fiberglass cloth and polyester resin, which had
water incursion and the planks rotted inside the glass. We have a local skiff
builder here that makes an excellent plywood/fiberglass skiff using Systems 3 epoxy, and he uses glass cloth below the water line for abrasion protection. I used Systems 3 epoxy to
repair my old glass over
plywood fishing boat, and also used it to build glass over plywood
hatch covers, the boat has long since been dead, and I am still using the
hatch covers as pallets put stuff on; I built those 20 years ago. I am a believer in epoxy. I do not have experience with the West system epoxy. The general consensus in my village is, if you use polyester resin on a
wood boat it is a death sentence. If you fully encapsulate take your time with the process and be very thorough, if you don't encapsulate, you are leaving yourself open for water to capillary into the
wood and anywhere you get a high moisture content you will have
rot. I would be inclined to coat everything. Would it be cost effective to re-plank the vessel and not use any coating?