Not sure if this might work for you. I remember seeing something about electric motors that attach to your big motor. Minn Kota has them all the way up to 202 ft/lbs at 36 volts. Here is the webpage.
http://www.minnkotamotors.com/products/motors/engine_mount/engine_mount.asp#Features
Ihope the link works and i did this right. I'm new to BR and still getting a feel for things.