Installation instructions can be found here . Essentially you want make sure that the impeller is mounted closer to the bow then the stern. We give a guideline that it should be within 6 meters from the bow. You really want to avoid mounting toward the stern as this will introduce more water turbulence and give less accurate readings. For best results, please run the impeller calibration routine to enter the appropriate impeller calibration reading. Calibration should be done on a per boat basis, so if you use the unit in different boats, you should run the calibration routine on each one.