Kayak motors

Has anyone seen those dive motors you use underwater. You hold on to it and it pulls you around under water. I was thinking about rigging up my yak with one to troll with. What do you all think.

Hey someone had to start the string.

GREAT!,
 If you only want to fish for an hour. Thats all the batteries last.
A friend of mine bought one last summer. Fun for the kids in the river but not ergonomic for a yak.
Some of the first issues I see are, packing it ( its bulky and heavy), attaching it and steering it.
Much easier and more sensible is a trolling motor if you just have to have a power boat!
But then even better would be a powerboat with a 100 HP motor and.....

We have tried every thing possible with a kayak and though it might be fun for a time it always comes back to (k.i.s.s.) keep it simple stupid.....there already close to perfect...but that coming from a gear juky that can't follow his own advice..Jim l