An in-hull transducer bounces its sonar signal through a solid fiberglass hull. This is possible because fiberglass has sonar properties similar to water. For optimal results, you should observe the following recommendations with regard to your vessel's hull.

• On single thickness fiberglass hulls up to 16 mm (⁵/₈ in.), you can mount an in-hull transducer as flat as possible in the bilge (lowest area inside of the hull) near the transom.

• You must mount the in-hull transducer over solid fiberglass, with no dead (hollow) space or core in the boat hull. In-hull transducers are not for use with metal, wood, or cored fiberglass hulls.

  You can mount the in-hull transducer near the keel (centerline) if you ensure the keel does not block the signal or cause an echo.

• You should not mount in-hull transducers over hull features that increase hull thickness beneath the device or over fittings, water intake or discharge ports that agitate the water.

• An in-hull transducer performs well on power boats and sailboats when it is properly placed and installed.

• You should verify the maximum deadrise angle for the transducer, which varies by model.