Re: ? on stringer replacement
This is one of the classic questions here - I think everyone new to this stuff has asked it at some point.
The short answer is no, it won't work because A) The plastic planking is not stiff enough to do the job B) Epoxy and poly resin won't stick to it so you can't secure it in place and C) It's much heavier than actual wood, which wastes fuel and damps down performance.
The right thing to use for stringers if you're rebuilding without wood would be corecell or one of the other high density foams. Expensive, but it never rots. Alternatively you could use a form made of cardboard or plastic and mold the stringers to be hollow fiberglass outside the boat - this is a lot of work and takes practice to get right, but will give you never rotting stringers too.
What most people here do is use high grade exterior plywood or marine grade plywood to core the stringers, tab to the hull, cover with about 3 layers of 18 oz glass, then as long as they're sealed by the glass they'll last a good 20-30 years... longer probably than you'll own the boat.
Erik
