I live on Lake supperior and motor sail my boat all the time, I fabricated my own electric motor mount that also carries the battery. This works well as it is mount under the first cross bar so when it is horizontal it is well up out of the water. I believe it helps as added ballast on a wicked day as I single hand alot. Nobody seems to want to brave Gichagumee.
The added bonus is that I can run a wire up my mast and have a beatuful glowing light at the top of my mast as I gaze up at the fire works on the bay on the fourth of july .
Email me and I can show you a sketch of my mount. Any fabricater will do the job for you as they think it is pretty cool