Gas or electric trolling motor on my 14' Fibergl v-hull?

I just need to know if an electric motor would do the job for my boat, or if I should pick a gas motor. Also I would have to rear mount the motor and I don't have much room. Can I find a gas motor almost that small, or will I be stuck with electric. All I really want is to have something in case my old outboard quits on me in the middle of the lake. I have a deep cycle battery for the main motor, can I use that or will I need to find another.