Mike:

I was thinking the same thing! I have built a Great Auk stripper, and was looking for an interesting new project. I am at the information gathering stage right now, but I did get to see some cool pedal-powered boats a couple weeks ago here in Buffalo. A small lake in Delaware Park hosted the human powered vehicle association gathering. Some of those boats could fly! Probably even pull a small water-skiier....

Anyway, I think the project wouldn't be all that tough. Does anyone sell just the pedal powering fins? Making your own drive system would make this project a lot more difficult.

Good luck, and keep everyone posted on your progress.

-Charlie