Abstract: A boat trim control system that includes a boat having a bull and means such as trim tabs mounted to the hull for trimming attitude of the boat as the bull is propelled through the water. The system includes facility for selectively adjusting the trim tabs to maintain a desired boat attitude under varying load and sea conditions. A sensor is mounted on the boat hull to provide an electrical sensor signal as a function of boat attitude, and is connected to electronic control circuitry responsive to the sensor signal for determining attitude of the boat bull. This electronic control circuitry further includes facility for operator setting of a desired boat attitude.