Go with gas
I tried the trolling motor routine on my 82 DS and found that is just didn't cut it. It got relegated to pushing my dinghy while I bought a 4hp Mariner to push the boat. I found the engine used for $300 in like new condition.There are two problems with the trolling motor that I found:1. Trolling motors produce torque, not speed. This meant that the trolling motor had no problem pushing the boat through the water, but that I often wound up going backwards because I was only getting 3 knots in a four knot current. To give you a sense, the trolling motor doesn't push my Walker Bay (8 foot dink) any faster than it pushed the DS. 2. The trolling motor had extremely limited range, even with a big battery, and you can't just refuel it. I got tired of lugging my battery out to the boat in the dink, using it, then lugging it home. If you plan to trailer your boat each time you want to use it, it might go better for you, but if you're going to moor it then its a hassel.I found the 4hp to be perfect for the DS. Any bigger and the trim of the boat would have been adversely affects. With the C/B up and just me in the boat, I could get it to just plane with the 4hp, as long as the water was fairly calm.Good luck,Justin - O'day Owners' Web