Steering assist system for boat

Abstract

A steering system can be provided for a boat. Such a boat can include a rudder device using an electric actuator to allow a rudder to rotate about a rotational shaft, and a steering wheel 7 for operation by an operator. The steering system can include a steering wheel displacement sensor for detecting the displacement of the steering wheel and a controller for calculating the rotational displacement of the rudder device corresponding to the detected steering wheel displacement and sending an actuation signal to the electric actuator based on the calculated rotational displacement, in which the controller receives a signal indicating an engine speed for producing a propulsive force in the boat, and changes, in accordance with the engine speed, the ratio of the rotational displacement of the rudder relative to the steering wheel displacement.

1 . A steering system for a boat comprising an engine configured to provide propulsion for the hull and a rudder device including an electric actuator to rotate a rudder about a rotational shaft, a steering wheel configured to be operated by an operator of the boat, a steering wheel displacement sensor configured to detect the displacement of the steering wheel, and a controller configured to calculate the rotational displacement of the rudder device corresponding to the detected steering wheel displacement and to send an actuation signal to the electric actuator based on the calculated rotational displacement, the controller being further configured to receive a signal indicating a speed of the engine, and to change, in accordance with the engine speed, a ratio of the rotational displacement of the rudder relative to the steering wheel displacement.  
   
   
       2 . The steering system according to  claim 1 , wherein the ratio is varied in stages in accordance with the preset ranges of the speed of the engine.  
   
   
       3 . The steering system according to  claim 1 , wherein the engine is mounted in an outboard motor.  
   
   
       4 . The steering system according to  claim 1  additionally comprising a load sensor configured to detect loads applied to the rudder and a reaction torque motor configured to apply a torque to the steering wheel, the controller being configured to apply a torque to the steering wheel based on loads detected by the load sensor.  
   
   
       5 . The steering system according to  claim 1 , wherein the ratio is changed proportional to changes in the speed of the engine.  
   
   
       6 . The steering system according to  claim 1 , wherein a value of the ratio is changed incrementally with incremental changes in the speed of the engine.  
   
   
       7 . A steering system for a boat comprising an engine configured to provide propulsion for the hull and a rudder device including an electric actuator to rotate a rudder about a rotational shaft, a steering wheel configured to be operated by an operator of the boat, a steering wheel displacement sensor configured to detect the displacement of the steering wheel, and means for changing a ratio of the rotational displacement of the rudder relative to the steering wheel displacement in accordance with the engine speed.  
   
   
       8 . The steering system according to  claim 7  additionally comprising means for detecting loads applied to the rudder and means for applying torque to the steering wheel based on the loads detected by the means for detecting loads.