Abstract: An electronic position monitor (10) and readout device (72, 90) for trim tabs on boats in which the monitor and readout device are connected to the trim tab controls. The device is electronic and position display is based on the time required for trim tab movement. Signals from the trim tab controls produce signals from timers (62, 63) which in turn are directed to enabling circuits (58, 60). If the enabling circuits pass the timer signals, they are counted in counter circuits (44, 46) and thence directed to a decoder (64) and finally to the display panel (72-90). The display panel is arranged to show the precise angular position of the trim tabs to the boat operator.

Abstract: Automatic trim tab control system (10) for boats in which the controls are provided with an attitude sensing switch (14) which provides port/starboard, fore/aft correction signals to the system (10) for trim tab correction. A timing means (18) in the control system enables signals from the attitude sensing switch, if corrections are required, to be amplified (16) and then directed to the switching relays (20) for the trim tabs or other device requiring altitude correction. A digital embodiment (134) may also be used for applications other than boats.