Jet propulsion boat

Abstract

A jet propulsion boat includes: a boat body; a jet water stream generation device that jets a jet water stream from the boat body to impart a propulsion force in a front-rear direction to the boat body; a steering device including a steering operator operated by a driver, and changes an orientation in a lateral direction of a propulsion force of the jet water stream generation device in response to an operation on the steering operator; an auxiliary propulsion device provided on the boat body to impart a propulsion force in a lateral direction to the boat body; and a control device that controls the auxiliary propulsion device based on an operation of the steering device.

1 . A jet propulsion boat comprising:
 a boat body;   a jet water stream generation device that jets a jet water stream from the boat body to impart a propulsion force in a front-rear direction to the boat body;   a steering device including a steering operator operated by a driver, and changes an orientation in a lateral direction of a propulsion force of the jet water stream generation device in response to an operation on the steering operator;   an auxiliary propulsion device provided on the boat body to impart a propulsion force in a lateral direction to the boat body; and   a control device that controls the auxiliary propulsion device based on an operation of the steering device.   
     
     
         2 . The jet propulsion boat according to  claim 1 , wherein the control device controls the auxiliary propulsion device based on an operation of the steering device and a state of the boat body. 
     
     
         3 . The jet propulsion boat according to  claim 2 , wherein the control device drives the auxiliary propulsion device when an operation amount of the steering device is greater than a predetermined amount and the boat body is in a predetermined state. 
     
     
         4 . The jet propulsion boat according to  claim 1 , wherein the control device controls the auxiliary propulsion device such that the orientation in the lateral direction of the propulsion force of the jet water stream generation device is same as an orientation in the lateral direction of the propulsion force of the auxiliary propulsion device. 
     
     
         5 . The jet propulsion boat according to  claim 1 , wherein the control device controls the auxiliary propulsion device such that the orientation in the lateral direction of the propulsion force of the jet water stream generation device is opposite to an orientation in the lateral direction of the propulsion force of the auxiliary propulsion device. 
     
     
         6 . The jet propulsion boat according to  claim 1 , wherein the control device increases the propulsion force of the auxiliary propulsion device as an operation amount of the steering device is large. 
     
     
         7 . The jet propulsion boat according to  claim 1 , wherein the control device increases the propulsion force of the auxiliary propulsion device as the propulsion force of the jet water stream generation device is large. 
     
     
         8 . The jet propulsion boat according to  claim 1 , comprising a throttle operator provided on the boat body and operated by the driver to increase or decrease the propulsion force of the jet water stream generation device,
 wherein when the boat body is traveling, the steering device is operating in a direction of turning the boat body to one side of the lateral direction, and an operation amount of the throttle operator is equal to or less than a predetermined determination operation amount, the control device drives the auxiliary propulsion device and controls the auxiliary propulsion device such that the propulsion force of the auxiliary propulsion device acts in a direction of turning the boat body to the one side of the lateral direction.   
     
     
         9 . The jet propulsion boat according to  claim 1 , wherein the control device determines whether a predetermined stabilization condition is satisfied based on the operation of the steering device, and when the stabilization condition is satisfied, the control device controls the auxiliary propulsion device such that the propulsion force of the auxiliary propulsion device acts in a direction of stabilizing an attitude of the boat body. 
     
     
         10 . The jet propulsion boat according to  claim 9 , wherein
 the stabilization condition includes a condition that a yaw rate of the boat body exceeds an allowable range set based on the operation of the steering device, and   when the stabilization condition is satisfied, the control device drives the auxiliary propulsion device and controls the auxiliary propulsion device such that the yaw rate of the boat body falls within the allowable range.   
     
     
         11 . The jet propulsion boat according to  claim 9 , wherein
 the stabilization condition includes a condition that a roll angle or a roll rate of the boat body exceeds a predetermined allowable range, and   when the stabilization condition is satisfied, the control device drives the auxiliary propulsion device and controls the auxiliary propulsion device such that the roll angle or the roll rate exceeding the allowable range falls within the allowable range.   
     
     
         12 . The jet propulsion boat according to  claim 1 , wherein
 the steering operator is pivotally operated in the lateral direction from a predetermined neutral position, and   includes a detection device that detects an operation direction and an operation amount of the steering operator, and   the control device controls the auxiliary propulsion device based on a detection result of the detection device.   
     
     
         13 . The jet propulsion boat according to  claim 1 , wherein the control device switches a control mode of the jet water stream generation device between a plurality of modes, and controls the auxiliary propulsion device based on the operation of the steering device and a type of the control mode of the jet water stream generation device.