A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A device for redirecting the reverse jet stream flow created by a watercraft to provide a lateral thrust. A first and second main body of device is fixed to the deflector nozzle within first and second reverse nozzle outlet channels, respectively. Each main body has a channel disposed therein. Each channel has a bend that fluidly connects an inlet to an outlet. The reverse flow enters the respective inlet in a downward and backward direction with respect to deflector nozzle. The respective inlet and channel of main body bend the reverse flow such that, when the reverse flow exits the outlet, the reverse flow is primarily lateral.

A device for redirecting the reverse jet stream flow created by a watercraft to provide a lateral thrust. A first and second main body of device is fixed to the deflector nozzle within first and second reverse nozzle outlet channels, respectively. Each main body has a channel disposed therein. Each channel has a bend that fluidly connects an inlet to an outlet. The reverse flow enters the respective inlet in a downward and backward direction with respect to deflector nozzle. The respective inlet and channel of main body bend the reverse flow such that, when the reverse flow exits the outlet, the reverse flow is primarily lateral.

A method for controlling a marine vessel having first and second steering nozzles and first and second trim deflectors comprises generating at least a first set of actuator control signals and a second set of actuator control signals. The first set of actuator control signals is coupled to and controls the first and second steering nozzles, and the second set of actuator control signals is coupled to and controls the first and second trim deflectors. The acts of generating and coupling the first set of actuator control signals and the second set of actuator control signals result in inducing any of a net yawing force, a net rolling force, and a net trimming force to the marine vessel without inducing any other substantial forces to the marine vessel by controlling the first and second steering nozzles and the first and second trim deflectors. Also disclosed is a system for controlling a marine vessel.

A method for controlling a marine vessel having first and second steering nozzles and first and second trim deflectors comprises generating at least a first set of actuator control signals and a second set of actuator control signals. The first set of actuator control signals is coupled to and controls the first and second steering nozzles, and the second set of actuator control signals is coupled to and controls the first and second trim deflectors. The acts of generating and coupling the first set of actuator control signals and the second set of actuator control signals result in inducing any of a net yawing force, a net rolling force, and a net trimming force to the marine vessel without inducing any other substantial forces to the marine vessel by controlling the first and second steering nozzles and the first and second trim deflectors. Also disclosed is a system for controlling a marine vessel.

A small watercraft system includes: a watercraft body; a watercraft body manipulation member through which a watercraft body manipulation command is input by an operator; a drive source that allows the watercraft body to plane; a steering device that allows the watercraft body to be steered; and a control device that controls the drive source and the steering device to operate the watercraft body. The control device determines whether a mode switching condition is satisfied, the mode switching condition including an operator's absence condition that the operator is absent from the watercraft body. Upon determining that the mode switching condition is satisfied, the control device executes an operator-absent manipulation mode in which the control device moves the watercraft body by controlling the drive source and the steering device based on an operator-absent manipulation command independent of the watercraft body manipulation command.

A small watercraft system includes: a watercraft body; a watercraft body manipulation member through which a watercraft body manipulation command is input by an operator; a drive source that allows the watercraft body to plane; a steering device that allows the watercraft body to be steered; and a control device that controls the drive source and the steering device to operate the watercraft body. The control device determines whether a mode switching condition is satisfied, the mode switching condition including an operator's absence condition that the operator is absent from the watercraft body. Upon determining that the mode switching condition is satisfied, the control device executes an operator-absent manipulation mode in which the control device moves the watercraft body by controlling the drive source and the steering device based on an operator-absent manipulation command independent of the watercraft body manipulation command.

Systems, methods, and devices for enhancing steering control of a recreational vehicle. One or more mechanical dampers are coupled to and resist movement of a steering system of the recreational vehicle, and an electrically actuated device is coupled to the steering system for applying torque to the steering system. A sensor is also positioned adjacent the steering system that generates data indicating an operational state of the recreational vehicle. A first torque applied to the steering system by the one or more mechanical dampers is estimated based on the operational state, a second torque to apply to the steering system by the electrically actuated device is calculated based on the estimated first torque and the operational state, and the electrically actuated device is operated to apply the second torque to the steering system.