As the propeller rotates, it pushes water forcefully in the direction of its rotation, creating a current called the prop wash. The prop wash can interfere with the transducer's sonar signal and can damage the transducer and propeller. You should observe the direction of propeller rotation and mount the transducer away from the prop wash. You can best observe the direction of rotation and areas affected by the prop wash while the vessel is moving.

Clockwise rotation generates turbulence on the port side, the left side of the boat when you face the front of the boat. In this case, you should mount the transducer on the starboard side, the right side when you face the front.

Counter-clockwise rotation generates turbulence on the starboard side. In this case, you should mount the transducer on the port side.