The "Ganymede" is part of Nick Schade's Jupiter Point series of kayaks.  These designs are intended as a collection of versatile, easy-to-build, fun-to-paddle kayaks. With a simple 3-panel hull and unique 3-panel deck, the boats are quick to assemble, have a lot of character, and perform very well. Plans are currently available for Ganymede, a 13' recreational kayak that uses 3 sheets of plywood. You can download free plans from Nick Schade's website. 

"Ganymede" is suitable for full-size adults who want a small kayak or smaller women or children who want a boat that is the right size for them. It is not too wide for smaller paddlers to use comfortably. This also means it is not going to be a super-stable boat, but it will have plenty of stability for most paddlers, while not being slow like many fatter recreational boats.

"Io" is 7-foot-long child's kayak built in a weekend or two from a single sheet of plywood.  Construction is extremely simple, but rugged enough for real use.  The payload for the Io is a maximum of around 75 pounds.