I have never mounted a transducer to my transom, other than on an aluminum boat I owned many moons ago. If the boat has a jackplate, there are all kinds of ways to mount whatever transducer where it is better protected and cannot cause turbulence to the prop. For strictly depth readings, you need a puck that shoots through the hull.The thought of drilling holes in my transom has just always been a bad thing for me.2017 Sabre FTD AE DC2017 Yamaha 175 SHOMK Fortrex 80Helix 10 Mega SI in consoleHelix 7 GPS SI GN2 on bow