I have found that by not putting the trolling motor all the way down I could get more speed. That's on a tin boat as well. A good test would be to drop it all the way down and run it on rabbit. See how fast your running and then pick the motor up a bit and test it again. I would be willing to bet there is going to be a midway spot that you get the most speed, and to me that's gonna help you save some battery.