Autometer Marine White Gauge 2-5/8in Electric Trim Level Gauge 0OHM Down - 90OHM UpThe" attitude" of a boat in the water can be controlled to a large extent by" trimming" the outdrive propeller unit in relation to the stern of the boat. As the drive is trimmed up,the prop exerts more force downward,causing the bow to lift out of the water. As the drive is trimmed down,the force is exerted more in line with the boat hull,resulting in the bow riding lower in the water. Depending on a given trim angle,you can see increased or decreased