Installed against the inside of the hull bottom, the in-hull transducer sends its signal through the hull. “Shoot through hull” transducers do not need direct water contact. They are glued to the inside of the hull with silicone or epoxy. An in-hull transducer is a good choice for a trailered boat, a vessel with a stepped hull, and for other types of high-performance hull designs, as there is no drag, hull penetration or potential for fouling.