A boat has a propulsion unit and a steering system. The steering system includes a steering device actuated by an electric actuator. A steering wheel operated by an operator is electrically connected to the actuator. Detectors collect data regarding one or more of operation status of the steering wheel, running status of the boat, status of the propulsion unit(s), status of the electric actuator, and the like. Based upon such collected data, a current for powering the electric actuator may be selectively increased to provide increased torque to ensure excellent steering response even in changing.