Thinking of putting a 55 lbs. thrust trolling motor on a 20 ft. pontoon as a back-up. years ago I had a 55# thrust on a 24 ft. But I only used it one time and I don't remember how fast it was. It would be used in some current (about 3 m.p.h.) Would this work, about what kind of speed could I expect(no current). Going wide open about how much time would it take for 55 lbs. trolling motor to drain a 12 volt deep cell battery. I know this is hard to answer, just a best guess please. Thanks for any advice