There are a lot of sites on boat building and reconstruction, with some very good advice on them
glen-l.com has a forum and several how-to's,
Boat plans, boat building kits for amateur boat builders
Plus a few decent plans, think it's primarily stitch and glue plywood designs, but the fiberglass information is pretty good.
Building Methods: Fiberglass Core 01 shows a method I've used on many projects long before I'd heard of glen-l. Depending on the complexity of the shapes, it's very easy. For complex curves that would be too hard to form in wood, I've used the foam both as a former and as the core. If you go this route, it's often cheaper to buy 2x4 or 2x6 stock and rip it down to make the form than it is to buy enough 1x. The exception is where you need a 1x4 or 1x6 it's much better to buy the right boards (unless you are equipped to resaw on the bandsaw)
do a search for boat plans, and browse around many have forums, and how to sections.
Ken.