-- Last Updated: Sep-23-11 8:46 PM EST --
I don't see how a trolling motor mounted amidship or slightly closer to the stern would do a very good job of steering a solo canoe.
Since you already have a motor have you considered mounting the motor on the bow of the canoe? You should be able to rig some kind of plate to mount the motor on the deck plate of the bow.
You would then have to remove the screws that secure the top of the motor to the shaft and rotate the head of the motor 180 degrees. Then just add a telescopic extension handle and you will be able to pull the boat along.
I've seen transom mount trolling motors run on the bow of many small boats and they seem to work well. I'm sure it could be done with a canoe too.
Tim Murphy AKA Goobs