Adjustable leveling fin rudder method and apparatus for powerboats

Abstract

Method and apparatus for leveling or adjusting a power-boat's average angle of bank or list about its roll axis RA regardless of side wind or off-center loading to improve passenger comfort, increase fuel efficiency, and smooth hull passage through waves with reduced pounding. Improved operating characteristics are accomplished by adjusting steering force angle-of-attack of a small fin-rudder mounted under a forward portion of the boat's keel. The boat's heading is maintained by applying an opposite steering force by altering thrust direction of the driving and steering mechanism. Altering thrust direction occurs either by a pilot steering the helm or automatically by adjusting thrust direction independently of pilot steering. In an optional automatic mode, an electronic gravity inclinometer adjusts a fin-rudder servo. An electronic filter processes the inclinometer signal to control the boat's average attitude around its roll axis RA. For providing further automation, thrust direction of the driving and steering mechanism is adjusted substantially simultaneously and proportionally with adjusting fin-rudder angle-of-attack and without pilot steering. The boat's heading is maintained while adjusting fin-rudder angle-of-attack by compensatingly adjusting thrust direction of driving and steering. For further automation, a flux-gate compass controls thrust direction for holding the boat's heading while adjusting fin-rudder angle-of-attack.