Going slow with the trolling motor is a good move. Half the time I'll be on the lowest setting and then turn it off as the momentum carries me. Once I stop I'll do it again. I only ever go fast enough to keep forward momentum. Also try throwing a shallow diver/rising lure out the back. I do this with a shadow rap sometimes and it usually produces as I'm trolling along. When you stop it just floats to the top, pretty much snaggless this way.