Patent ID: 7220156

Claim:
A system for controlling steering of an outboard motor adapted to be mounted on a stern of a boat and having an internal combustion engine powering a propeller, comprising: an actuator which steers the outboard motor relative to the boat; a rotation angle sensor which detects a rotation angle of a steering wheel installed at the boat; a plurality of steering angle sensors which each detect a steering angle of the outboard motor relative to the boat; a controller which determines a drive current to be supplied to the actuator based on the detected rotation angle and at least one of the detected steering angles and supplies the determined drive current to the actuator to control operation of the actuator; an engine speed sensor which detects a speed of the engine; a steering angle estimator which estimates the steering angle of the outboard motor relative to the boat, based on the determined drive current and the detected engine speed; and a steering angle sensor failure detector which detects failure of the steering angle sensors; wherein the controller determines the drive current based on the detected rotation angle and the estimated steering angle, when all of the steering angle sensors are detected to have failed.