Garmin Heavy Duty Transom MountModel: 010-12006-10
Easily attach your compatible 4-, 8- or 12-pin transducer to the transom of your boat with this mount, which provides excellent sonar returns at all speeds. 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.
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.