If you really want to build one, use the kit for templates and use a good grade plywood instead of the doorskin. Using Aeromarine, Speedmaster or one of the other current hardware suppliers for running gear will help but, if you really want it to work, you're going to need to make it much lighter and get to out of the water more than what they have run at. If you check out my thread, Re-engineering a Dumas Pay' N Pak, you will see what I mean
http://www.rcuniverse.com/forum/spee...-payn-pak.html