I used a little Humminbird Pirhanamax series for a lot of years. Small Simple, easy to use and read. and plenty good for depth and finding structure. I see they have em for $70 at Bass Pro. Plenty cheap and sounds like it would be a lot better than what you've grown accustomed to. They have a separate transducer you can buy just for trolling motors. hockey puck shaped that is lot less susceptible to breakage in the stumps. I found one for $30 on ebay. Hope this helps