: How about an 8 foot long catamaran you can build in an afernoon?

This sounds GREAT!
An 8 foot cat(as Paul suggests), maybe 4 feet wide (so it fits in the truck) that you can not only use for crabbing, but use it as a swimming float for the kids to dive off of, or better yet hook on an electric motor and cruise the lakes. I like the idea of something that can be built so quickly, that is stable enough to pull the kids behind the kayak. When I was a growing up, near our rustic beach cabin, my dad and I found two plastic pontoons and built a catamaran that we mounted a 9 horse Evinrude on the back. I would not recommend doing this, nor would I build one for my kids. Way too much power, but boy did it scream. But I see no reason why you couldn't just paddle it, or better yet, the electric motor.

I would like more ideas on the design.

I think that Paul's pontoon idea is right on the mark - Foam covered with fiberglass and epoxy. The deck is what I'm interested in. How about 1/2" bendable birch covered with epoxy, bend it in order to flair up the front, so that it doesn't take on much water. Sides could also be some 1/2" ply, maybe 8-10" high. Mount this "tub" to wood blocks with threaded bolts glued with thickened epoxy flush with the surface of the pontoons. Use large wing nuts for easy assembly/disassembly. Install a stadium chair or fishing seat, pop holders, glove box for sunglasses & sun tan lotion, cd player, what else....
I agree with Paul, a basic version (back to reality) could be built in a weekend for not much money. I enjoy kayak building (alot), but this seems like a fun weekend. And you could still use it for fishing & crabbing.
Thanks to all for the ideas, I think I'll get started right away.
SMF