Automatic trim tab control for power boats

Abstract

Adjustment of a power boat's trim tabs is automated throughout all phases of the operation of the boat. The boat's speed and/or the revolutions of its engine(s) are sensed and used by electronic circuits, including microprocessor-based circuits, to control prime movers, typically hydraulic pumps, in order to move the trim tabs to their optimal position. In one embodiment the boat's speed is sensed by a speedometer. Below a first predetermined speed, the boat's trim tabs are moved full down. Above a second, higher, predetermined speed the trim tabs are moved full up. In another embodiment the trim tabs are further adjusted in and about their up position, and while the boat is on-plane, so as to optimize the performance of the boat. The boat's on-plane performance is monitored by a speedometer or, preferably, by one or more tachometers. After the boat has exceeded the first predetermined speed, after the trim tabs have been initially adjusted to their full up positions, and after the speedometer or tachometer(s) is (are) continuously reading values within some small, preset, range, the trim tabs are perturbed slightly in position. The boat's throttle remains unchanged. After a settling time any effect of the changed trim tab position on the boat's performance is assessed. The trim tabs are moved in position until performance is no longer improved by further perturbations in position.