Thru-hull transducers are mounted through a hole drilled in the bottom of the boat and protrude directly into the water. This type of transducer generally provides the best performance.
Thru-hulls are recommended for displacement hulls and boats with straight-shaft inboard engines. You'll also need a fairing block that allows the transducer to be mounted properly. Thru-hull transducers must be installed with a fairing to ensure proper alignment and a secure fit.
Thru-hull transducers must be positioned in front of the propeller, rudder, keel or anything else that may create turbulence. They must be mounted in a position that is always underwater and angled straight down.