Ocean,
I use one on my dinghy with good results but I question how well it would work as a kicker. If you get into trouble, it might give the option of which rock to hit, that's about it. However, there is a product line called a Torquedo; electric outboards in the 4-6 hp range. Pretty expensive and they won't divulge longevity or range. My take on it is that it's easier in a pinch to wave down a passing stink-potter and bum a gallon of petrol than it is to ask him to hook up and recharge your battery for a few hours. That's my two cents. But, I love my trolling motor for my dink. It's quiet, small, cheap and will last a full week of put-zing around when we cruise. Oh, and no tune ups, emissions, ethanol issues.
Don