Garmin Heavy Duty Transom Mount with Spray Shield (4/8/12-pin Transducers)

Since the transducer is in the water at all times, the mount does not protect the transducer from underwater obstructions and some drag on the boat will occur. The included transducer spray shield reduces excessive water spray from your compatible transducer when your boat is running at high speeds

You also can mount the transducer to the step of your boat with this mount to allow angle adjustment of the transducer so it is parallel with the water surface; this will create no drag on the boat. And since the transducer is out of the water with this mounting style, sonar will not track bottom when the boat is on plane.