converting a rowing kayak to foot pedal

[projectile]

Does anyone know how easy/difficult it would be to convert a rowing kayak to a foot pedaling yak? I don't have one yet and I could not tell you a model. I am think about one that can carry two divers.

Thanks
Projectile

[seahunter]

hobie makes them... http://www.hobiecat.com/kayaking/index.html