Jet propulsion system, jet propulsion watercraft, and watercraft body launching method

Abstract

A jet propulsion system includes a jet propulsion mechanism located at a stern of a watercraft body and including a nozzle including a jetting port to eject a jet of water to generate a propulsive force, a nozzle actuator to rotate the nozzle to change an orientation of the jet of water, and a controller configured or programmed to perform an oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to Japanese Patent Application No. 2024-197827 filed on Nov. 13, 2024. The entire contents of this application are hereby incorporated herein by reference.BACKGROUND OF THE INVENTION1. Field of the Invention

[0002] The present invention relates to jet propulsion systems, jet propulsion watercrafts, and watercraft body launching methods.2. Description of the Related Art

[0003] A jet propulsion watercraft including a jet propulsion mechanism is known in general. Such a jet propulsion watercraft is disclosed in Japanese Patent Laid-Open No. 2011-189847, for example.

[0004] Japanese Patent Laid-Open No. 2011-189847 discloses a jet propulsion watercraft including a jet propulsion mechanism. The jet propulsion watercraft ejects a jet of water forward from the jet propulsion mechanism to generate a backward propulsive force for backward movement when a watercraft body is launched from a trailer.

[0005] However, in the jet propulsion watercraft described in Japanese Patent Laid-Open No. 2011-189847, simply repeatedly applying, to the watercraft body, a linear thrust in a launching direction in which the watercraft body is launched by ejecting a jet of water forward from the jet propulsion mechanism may not be enough to or may be unlikely to move the watercraft body in the launching direction, depending on the magnitude of a frictional resistance between the watercraft body and the trailer. In such a case, a launching operation may take a lot of time and effort. Therefore, it is desired to facilitate the launching operation to launch the watercraft body from the trailer.SUMMARY OF THE INVENTION

[0006] Example embodiments of the present invention provide jet propulsion systems, jet propulsion watercrafts, and watercraft body launching methods that each facilitate launching operations to launch watercraft bodies.

[0007] A jet propulsion system according to an example embodiment of the present invention includes a jet propulsion mechanism located at a stern of a watercraft body including a nozzle including a jetting port to eject a jet of water to generate a propulsive force, a nozzle actuator to rotate the nozzle to change an orientation of the jet of water from the jetting port, and a controller configured or programmed to perform an oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched.

[0008] A jet propulsion system according to an example embodiment of the present invention includes the controller configured or programmed to perform the oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched. Accordingly, when the watercraft body is launched, the position of the watercraft body is shifted by oscillating the watercraft body such that the watercraft body is released from friction with a trailer. Therefore, even when it is difficult or impossible to move the watercraft body in the launching direction by simply ejecting a jet of water forward, the watercraft body is effectively moved in the launching direction by oscillating the nozzle. Consequently, the watercraft body is easily launched.

[0009] In a jet propulsion system according to an example embodiment of the present invention, the nozzle actuator preferably includes a steering actuator to rotate the nozzle in a right-left direction to change the orientation of the jet of water in the right-left direction, and the controller is preferably configured or programmed to perform the oscillation control to oscillate the nozzle in the right-left direction using the steering actuator. Accordingly, the steering actuator is controlled to easily oscillate the nozzle repeatedly in the right-left direction. Consequently, a launching operation to launch the watercraft body is performed more easily.

[0010] A jet propulsion system according to an example embodiment of the present invention preferably further includes a remote control to maneuver the watercraft body by remote control, and a communicator on the watercraft body to communicate with the remote control, and the controller is preferably configured or programmed to perform the oscillation control based on an oscillation signal received from the remote control via the communicator. Accordingly, the remote control enables a person not on board the watercraft body to perform the oscillation control by operating the remote control.

[0011] In such a case, the remote control preferably includes an oscillation button to continuously transmit the oscillation signal for a pressing duration in which a pressing operation continues, and the controller is preferably configured or programmed to perform the oscillation control to oscillate the nozzle using the nozzle actuator based on the oscillation signal for the pressing duration. Accordingly, the oscillation button enables the nozzle to be oscillated to oscillate the watercraft body only while an operator of the oscillation button intentionally operates the oscillation button.

[0012] In a jet propulsion system including the remote control and the communicator, the remote control is preferably configured to receive an operation to move the watercraft body to a predetermined boarding position after launching of the watercraft body is completed. Accordingly, following the oscillation control to launch the watercraft body by operating the remote control, the watercraft body is able to be moved to the predetermined boarding position by operating the remote control that has instructed the oscillation control.

[0013] A jet propulsion system according to an example embodiment of the present invention preferably further includes a reverse bucket to change the orientation of the jet of water in a forward-rearward direction, and the controller is preferably configured or programmed to generate a backward propulsive force using the reverse bucket while performing the oscillation control. Accordingly, the reverse bucket generates a backward propulsive force simultaneously with oscillating the nozzle, and thus the launching operation to launch the watercraft body is performed more easily as compared with a case in which oscillating the nozzle and generating a backward propulsive force using the reverse bucket are performed separately.

[0014] A jet propulsion system according to an example embodiment of the present invention preferably further includes a reverse bucket to change the orientation of the jet of water in a forward-rearward direction, the nozzle actuator preferably includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller is preferably configured or programmed to, while performing the oscillation control, eject the jet of water in a direction that causes the stern to float by directing the jetting port of the nozzle upward using the trim actuator and adjusting a position of the reverse bucket relative to the nozzle to redirect the jet of water downward. Accordingly, the jet of water, the orientation of which has been adjusted by the trim actuator and the reverse bucket, enables the nozzle to be oscillated while the stern is floated higher in the water. That is, the nozzle is oscillated in a state in which a contact area between the trailer and the watercraft body is reduced to reduce friction. Consequently, the launching operation to launch the watercraft body is performed more easily.

[0015] In a jet propulsion system including the controller configured or programmed to perform the oscillation control using the steering actuator, the controller is preferably configured or programmed to oscillate the nozzle in the right-left direction within a maximum angular range in which the nozzle is movable by the steering actuator in the oscillation control. Accordingly, the nozzle is oscillated in the right-left direction within the maximum angular range such that a large oscillation is imparted to the watercraft body, and thus the launching operation to launch the watercraft body is performed even more easily.

[0016] In a jet propulsion system including the controller configured or programmed to perform the oscillation control using the steering actuator, the controller is preferably configured or programmed to oscillate the nozzle in the right-left direction with a period of, for example, 0.5 seconds or more and 4 seconds or less in the oscillation control. Accordingly, the watercraft body is effectively oscillated by oscillating the nozzle in the right-left direction with a short period of 0.5 seconds or more and 4 seconds or less, for example.

[0017] In a jet propulsion system including the controller configured or programmed to perform the oscillation control using the steering actuator, the steering actuator preferably includes an electric motor, a transmission gear to transmit a drive force of the electric motor to the nozzle, and a nozzle-side steering cable including a first end connected to the transmission gear and a second end connected to the nozzle to push and pull the nozzle, and the controller is preferably configured or programmed to control driving of the electric motor to push and pull the nozzle via the nozzle-side steering cable to perform the oscillation control to oscillate the nozzle in the right-left direction. Accordingly, the drive force of the electric motor is transmitted to the nozzle via the transmission gear and the nozzle-side steering cable to easily oscillate the nozzle in the right-left direction.

[0018] In such a case, the steering actuator preferably further includes an operator-side steering cable including a first end connected to the transmission gear and a second end connected to a steering operator to push and pull the steering operator, and the controller is preferably configured or programmed to push and pull the steering operator via the operator-side steering cable to also oscillate the steering operator in the oscillation control. Accordingly, the watercraft body is oscillated by not only the nozzle but also the steering operator, and thus a larger oscillation is imparted to the watercraft body.

[0019] In a jet propulsion system according to an example embodiment of the present invention, the nozzle actuator preferably includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller is preferably configured or programmed to oscillate the nozzle in the upward-downward direction using the trim actuator in the oscillation control. Accordingly, the nozzle is easily oscillated repeatedly in the upward-downward direction by the trim actuator. Consequently, the launching operation to launch the watercraft body is performed more easily.

[0020] A jet propulsion watercraft according to an example embodiment of the present invention includes a watercraft body, a jet propulsion mechanism located at a stern of the watercraft body including a nozzle including a jetting port to eject a jet of water to generate a propulsive force, a nozzle actuator to rotate the nozzle to change an orientation of the jet of water from the jetting port, and a controller configured or programmed to perform an oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched.

[0021] A jet propulsion watercraft according to an example embodiment of the present invention includes the controller configured or programmed to perform the oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched. Accordingly, when the watercraft body is launched, the position of the watercraft body is shifted by oscillating the watercraft body such that the watercraft body is released from friction with a trailer. Therefore, even when it is difficult or impossible to move the watercraft body in the launching direction by simply ejecting a jet of water forward, the watercraft body is effectively moved in the launching direction by oscillating the nozzle. Consequently, the watercraft body is easily launched.

[0022] In a jet propulsion watercraft according to an example embodiment of the present invention, the nozzle actuator preferably includes a steering actuator to rotate the nozzle in a right-left direction to change the orientation of the jet of water in the right-left direction, and the controller is preferably configured or programmed to perform the oscillation control to oscillate the nozzle in the right-left direction using the steering actuator. Accordingly, the steering actuator is controlled to easily oscillate the nozzle repeatedly in the right-left direction. Consequently, a launching operation to launch the watercraft body is performed more easily.

[0023] A jet propulsion watercraft according to an example embodiment of the present invention preferably further includes a communicator to communicate with a remote control configured or programmed to maneuver the watercraft body by remote control, and the controller is preferably configured or programmed to perform the oscillation control based on an oscillation signal received from the remote control via the communicator. Accordingly, the remote control enables a person not on board the watercraft body to perform the oscillation control by operating the remote control.

[0024] In a jet propulsion watercraft including the remote control and the communicator, the remote control preferably includes an oscillation button to continuously transmit the oscillation signal for a pressing duration in which a pressing operation continues, and the controller is preferably configured or programmed to perform the oscillation control to oscillate the nozzle using the nozzle actuator based on the oscillation signal for the pressing duration. Accordingly, the oscillation button enables the nozzle to be oscillated to oscillate the watercraft body only while an operator of the oscillation button intentionally operates the oscillation button.

[0025] In a jet propulsion watercraft according to an example embodiment of the present invention, the remote control is preferably configured to receive an operation to move the watercraft body to a predetermined boarding position after launching of the watercraft body is completed. Accordingly, following the oscillation control to launch the watercraft body by operating the remote control, the watercraft body is able to be moved to the predetermined boarding position by operating the remote control that has instructed the oscillation control.

[0026] A jet propulsion watercraft according to an example embodiment of the present invention preferably further includes a reverse bucket to change the orientation of the jet of water in a forward-rearward direction, and the controller is preferably configured or programmed to generate a backward propulsive force using the reverse bucket while performing the oscillation control. Accordingly, the reverse bucket generates a backward propulsive force simultaneously with oscillating the nozzle, and thus the launching operation to launch the watercraft body is performed more easily as compared with a case in which oscillating the nozzle and generating a backward propulsive force using the reverse bucket are performed separately.

[0027] A jet propulsion watercraft according to an example embodiment of the present invention preferably further includes a reverse bucket to change the orientation of the jet of water in a forward-rearward direction, the nozzle actuator preferably includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller is preferably configured or programmed to, while performing the oscillation control, eject the jet of water in a direction that causes the stern to float by directing the jetting port of the nozzle upward using the trim actuator and adjusting a position of the reverse bucket relative to the nozzle to redirect the jet of water downward. Accordingly, the jet of water, the orientation of which has been adjusted by the trim actuator and the reverse bucket, enables the nozzle to be oscillated while the stern is floated higher in the water. That is, the nozzle is oscillated in a state in which a contact area between the trailer and the watercraft body is reduced to reduce friction. Consequently, the launching operation to launch the watercraft body from the trailer is performed more easily.

[0028] A watercraft body launching method according to an example embodiment of the present invention includes generating a backward propulsive force using a jet of water from a jetting port of a nozzle of a jet propulsion mechanism when a watercraft body is launched from a trailer, and repeatedly oscillating the nozzle when the watercraft body is launched from the trailer.

[0029] A watercraft body launching method according to an example embodiment of the present invention includes repeatedly oscillating the nozzle when the watercraft body is launched from the trailer. Accordingly, when the watercraft body is launched, the position of the watercraft body relative to the trailer is shifted by oscillating the watercraft body such that the watercraft body is released from friction with the trailer. Therefore, even when it is difficult or impossible to move the watercraft body in the launching direction by simply ejecting a jet of water forward, the watercraft body is effectively moved in the launching direction by oscillating the nozzle. Consequently, the watercraft body is easily launched from the trailer.

[0030] The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a side view showing a jet propulsion watercraft on which a jet propulsion system is mounted according to an example embodiment of the present invention.

[0032] FIG. 2 is an enlarged side view showing a portion of a jet propulsion watercraft on which a jet propulsion system is mounted according to an example embodiment of the present invention.

[0033] FIG. 3 is a block diagram of a jet propulsion system according to an example embodiment of the present invention.

[0034] FIG. 4 is a side view illustrating an arrangement of a trailer and a jet propulsion watercraft when a launching operation is performed.

[0035] FIG. 5 is a plan view showing a state in which an oscillation control is performed by a controller of a jet propulsion system according to an example embodiment of the present invention.

[0036] FIG. 6 is a diagram showing a jet propulsion watercraft according to an example embodiment of the present invention and a remote control that wirelessly communicates with the jet propulsion watercraft.

[0037] FIG. 7 is a diagram showing a display screen of a remote control of a jet propulsion system according to an example embodiment of the present invention.

[0038] FIG. 8 is a schematic plan view illustrating right and left rotation of a nozzle of a jet propulsion mechanism of a jet propulsion system according to an example embodiment of the present invention.

[0039] FIG. 9 is a schematic side view illustrating upward and downward rotation (trim) of a nozzle of a jet propulsion mechanism according to an example embodiment of the present invention.

[0040] FIG. 10 is a schematic side view illustrating upward and downward rotation of a reverse bucket of a jet propulsion mechanism according to an example embodiment of the present invention.

[0041] FIG. 11 is a side view illustrating the orientations of a nozzle and a reverse bucket when a stern is lifted.

[0042] FIG. 12 is a partial enlarged view of a portion A in FIG. 2.

[0043] FIG. 13 is a diagram showing an operator according to an example embodiment of the present invention from the rear side.

[0044] FIG. 14 is a flowchart of a control process for an oscillation control according to an example embodiment of the present invention.DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

[0045] Example embodiments of the present invention are hereinafter described with reference to the drawings.

[0046] Jet propulsion watercrafts 100 according to example embodiments of the present invention are now described with reference to FIGS. 1 to 14.

[0047] The jet propulsion watercraft 100 shown in FIGS. 1 and 2 is a personal watercraft, for example, and sails with a relatively small number of people on board. The jet propulsion watercraft 100 is a so-called jet ski or jet bike that glides on the surface of the water. The jet propulsion watercraft 100 includes a watercraft body 110 and a jet propulsion system 120 mounted on the watercraft body 110. The watercraft body 110 includes a hull 111 that defines the bottom of the watercraft, a deck 112 located above the hull 111, and a seat 113 located at the center of the deck 112 in a right-left direction.

[0048] As shown in FIG. 3, the jet propulsion system 120 includes a communicator 1, a remote control 2, a jet drive source 3, a jet propulsion mechanism 4 including a nozzle 44 (see FIG. 1) to eject a jet of water, an actuator 5 to change the orientation of the jet of water, an operator 6, a GPS receiver 7, and a controller 8. The actuator 5 includes a steering actuator 50 and a trim actuator 55 to drive the nozzle 44, and a reverse actuator 56 to drive a reverse bucket 45. The steering actuator 50 and the trim actuator 55 are nozzle actuators 5a that rotate the nozzle 44 to change the orientation of the jet of water from a jetting port 44a.

[0049] In the figures, an X direction represents the forward-rearward direction of the jet propulsion watercraft 100. In the X direction, an X1 direction (FRD) represents a forward movement direction, and an X2 direction (BWD) represents a reverse movement direction. In the figures, a Y direction represents the right-left direction of the jet propulsion watercraft 100. In the figures, a Z direction represents the upward-downward direction of the jet propulsion watercraft 100, a Z1 direction represents an upward direction, and a Z2 direction represents a downward direction.

[0050] The jet propulsion system 120 (controller 8) according to an example embodiment of the present invention shown in FIGS. 4 and 5 performs an oscillation control to repeatedly oscillate the nozzle 44 using the nozzle actuators 5a when the watercraft body 110 is launched from a trailer T. In principle, the oscillation control is performed when no one is on board the watercraft body 110. The oscillation control is described below in detail.

[0051] The trailer T carrying the watercraft body 110 is positioned by a vehicle V towing the trailer T to touch the water surface from the land side. The position at which the trailer T touches the water surface is a sloping surface K that is lower on the trailer T side than on the vehicle V side. At this time, a water intake 40a in a lower portion of the watercraft body 110 is located underwater such that water is able to be taken into a water passage 40 (see FIG. 1). When the watercraft body 110 is launched, the trailer T has an inverted U-shape in a plan view, with the stern 114 side (X2 direction side) open. The trailer T includes a pair of watercraft body supports T1 extending in the forward-rearward direction of the watercraft body 110 and aligned in the right-left direction of the watercraft body 110. The watercraft body 110 is placed from above on the pair of watercraft body supports T1. The watercraft body 110 is located between the pair of watercraft body supports T1.

[0052] The communicator 1 shown in FIG. 3 is provided on the watercraft body 110. The communicator 1 establishes wireless communication with the remote control 2. As an example, the communicator 1 establishes wireless communication with the remote control 2 via Bluetooth (registered trademark). The communicator is not limited to Bluetooth and may be a wireless communicator using other communication standards, such as Wi-Fi (registered trademark). A watercraft operator causes the remote control 2 to establish wireless communication with the communicator 1 as preparations to travel on the jet propulsion watercraft 100 (see FIG. 6).

[0053] The remote control 2 is held by the watercraft operator of the jet propulsion watercraft 100, or by a watercraft maneuvering assistant. As an example, the remote control 2 is a smartphone. The remote control is not limited to a smartphone and may be a dedicated communication device to wirelessly communicate with the jet propulsion watercraft or a tablet terminal, for example. A dedicated application is installed in the remote control 2 to establish communication with the jet propulsion watercraft 100.

[0054] The remote control 2 is a device to instruct movement of the watercraft body 110 by wireless communication with the watercraft body 110. A wireless watercraft maneuvering mode in which movement of the watercraft body 110 is instructed by the remote control 2 includes the following two modes: a remote watercraft maneuvering mode and an automatic movement mode.

[0055] In the remote watercraft maneuvering mode, the watercraft body 110 is remotely operated using the remote control 2. When “remote watercraft maneuvering” of mode switching buttons 21 at the upper left of a display screen 20 (see FIG. 7) of the dedicated application of the remote control 2 is selected, the mode switches to the remote watercraft maneuvering mode. When “normal” of the mode switching buttons 21 is selected, the mode switches to a normal mode in which the watercraft operator operates a steering operator 60 to maneuver the jet propulsion watercraft 100. In the remote watercraft maneuvering mode, the jet propulsion watercraft 100 is freely remotely controlled to move using watercraft body operation buttons 22 (such as a forward (F) button, a reverse (R) button, and right and left turn buttons at the center of the screen) on the display screen 20.

[0056] In the automatic movement mode, the watercraft body 110 is automatically moved by remotely instructing the watercraft body 110 to move automatically using the remote control 2. The automatic movement mode includes modes such as automatic return, fixed point holding, and launching support. The launching support is a mode in which the oscillation control described above is performed.

[0057] As shown in FIG. 7, the remote control 2 includes an oscillation button 23 used for the oscillation control in the launching support mode. The oscillation button 23 is displayed at a lower portion of the display screen 20 when the launching support is selected. The oscillation button 23 continuously transmits an oscillation signal I1 to the controller 8 to cause the nozzle 44 to oscillate for a pressing duration in which a pressing operation continues. The oscillation button 23 includes a right-left oscillation button 23a to repeatedly oscillate the nozzle 44 in the right-left direction, and an upward-downward oscillation button 23b to repeatedly oscillate the nozzle 44 in the upward-downward direction.

[0058] The remote control 2 also includes a stern float button 24 used during launching support. The stern float button 24 is pressed to eject a jet of water in a direction i.e., substantially directly below (see FIG. 11), that causes the stern 114 to float higher in the water, for the pressing duration in which the pressing operation continues. The stern float button 24 continuously transmits a stern float signal I2 (see FIG. 3) to the controller 8 to cause a jet of water to be ejected in the direction that causes the stern 114 to float for the pressing duration in which the pressing operation continues. As shown in FIG. 11, while the oscillation control is performed, the controller 8 is able to eject a jet of water in the direction (substantially directly below) that causes the stern 114 to float by directing the jetting port 44a of the nozzle 44 upward using the trim actuator 55 (see FIG. 9) and adjusting the position of the reverse bucket 45 relative to the nozzle 44 to redirect the jet of water downward. That is, while the oscillation button 23 is pressed, the stern float button 24 is also pressed to eject a jet of water in the direction that causes the stern 114 to float. Even when the oscillation button 23 is not being pressed, the stern float button 24 is pressed to eject a jet of water in the direction that causes the stern 114 to float.

[0059] The remote control 2 receives an operation to move the watercraft body 110 to a predetermined boarding position after launching of the watercraft body 110 is completed. Such an operation is performed, for example, by pressing the watercraft body operation buttons 22 of the remote control 2 after launching support is switched to the remote watercraft maneuvering mode by pressing the mode switching button 21.

[0060] As shown in FIG. 1, the jet drive source 3 includes an engine 30, a crankshaft 31, and a coupling 32. The engine 30 is, for example, a multi-cylinder internal combustion engine. The crankshaft 31 is an output shaft to output a torque generated by the engine 30. The crankshaft 31 extends rearward from the engine 30. The coupling 32 is provided at the rear end of the crankshaft 31 and connects and fixes the crankshaft 31 to an impeller shaft 41 of the jet propulsion mechanism 4.

[0061] The jet propulsion mechanism 4 generates a propulsive force by ejecting a jet of water from the jetting port 44a of the nozzle 44. The jet propulsion mechanism 4 includes the water passage 40, the impeller shaft 41, an impeller 42, a nozzle 43 fixed to the rear end of the water passage 40, the nozzle 44 drivably installed on the nozzle 43, and the reverse bucket (reverse gate) 45.

[0062] The water passage 40 extends from the lower portion of the watercraft body 110 toward the stern 114. Water is taken into the water passage 40 through the water intake 40a in the lower portion of the watercraft body 110. The impeller shaft 41 extending rearward is provided in the water passage 40. The impeller 42 is fixed to the impeller shaft 41. The impeller 42 rotates integrally with the impeller shaft 41 to generate a rearward flow. The impeller shaft 41 is connected to the crankshaft 31 via the coupling 32. Therefore, the rotation speed of the impeller 42 increases or decreases as the rotation speed of the engine 30 increases or decreases.

[0063] The nozzle 43 shown in FIG. 8 performs a function to jet water flowing through the water passage 40 toward the rear nozzle 44. The nozzle 44 is attached to the nozzle 43 from the rear. The nozzle 44 is located at the stern 114 of the watercraft body 110. The nozzle 44 includes the jetting port 44a for ejecting or jetting a jet of water. The nozzle 44 functions as a deflector to change the orientation of the jet of water ejected from the jetting port 44a. Specifically, the nozzle 44 is attached to the nozzle 43 so as to be rotatable in the right-left direction around a central axis C1 of an upward-downward central shaft 46 extending in the upward-downward direction (the steering position is adjustable around the upward-downward central shaft 46). The central axis C1 is located at the center of the nozzle 44 in the right-left direction. The nozzle 44 is rotated in the right-left direction by the steering actuator 50.

[0064] The nozzle 44 shown in FIG. 9 is attached to the nozzle 43 so as to be rotatable in the upward-downward direction around a central axis C2 of a right-left central shaft 47 extending in the right-left direction (the trim position is adjustable around the right-left central shaft 47). The central axis C2 is located at the center of the nozzle 44 in the upward-downward direction. The nozzle 44 is rotated in the upward-downward direction by the trim actuator 55. Thus, the nozzle 44 is rotated in the upward-downward direction and the right-left direction such that the orientation of the jet of water ejected from the jetting port 44a changes.

[0065] The reverse bucket 45 shown in FIG. 10 changes the orientation of the jet of water in the forward-rearward direction. The reverse bucket 45 rotationally moves between a position above the nozzle 44 and a position behind the nozzle 44. When moving to the position behind the nozzle 44, the reverse bucket 45 covers the jetting port 44a from behind such that the jet of water is directed forward, and the orientation of the jet of water is changed forward. The reverse bucket 45 is rotatable in the upward-downward direction around a central axis C3 of a right-left central shaft 48 extending in the right-left direction. The reverse bucket 45 is rotated in the upward-downward direction by the reverse actuator 56. Depending on the position of the reverse bucket 45, the jet propulsion watercraft 100 switches between a forward movement state, a reverse movement state, and a neutral state in which a forward thrust and a reverse thrust are substantially equal to each other. The jet propulsion watercraft 100 is in the reverse movement or neutral state when the reverse bucket 45 covers the jetting port 44a from behind, and is in the forward movement state when the reverse bucket 45 does not cover the jetting port 44a from behind. The reverse bucket 45 includes, on both the right and left sides thereof, jetting openings 45a each having a substantially cylindrical shape with a central axis directed diagonally forward to the right of the watercraft body 110.

[0066] Referring to FIGS. 2 and 12, the steering actuator 50 includes an electric motor 51 as a drive source, a transmission gear 52 to transmit the drive forces of the electric motor 51 and the steering operator 60 to the nozzle 44, a nozzle-side steering cable 53, and an operator-side steering cable 54. In the wireless watercraft maneuvering mode, the steering actuator 50 uses the drive force of the electric motor 51 to rotate the nozzle 44 in the right-left direction to change the orientation of the jet of water from the jetting port 44a in the right-left direction. The steering actuator 50 is able to rotate the nozzle 44 in the right-left direction even when the jet of water is not being ejected.

[0067] The electric motor 51 includes a motor shaft 51a, a transmission shaft 51b, and a clutch 51c to switch a connection state between the motor shaft 51a and the transmission shaft 51b. The jet propulsion watercraft may not include a clutch. A bevel gear 51d is provided on the side of the transmission shaft 51b opposite to the clutch 51c.

[0068] The transmission gear 52 includes a first gear 52a including a bevel gear 521 to mesh with the bevel gear 51d and a pinion 522, and a second gear 52b including a rack to mesh with the pinion 522. The nozzle-side steering cable 53 includes a first end connected to the transmission gear 52 and a second end connected to the nozzle 44, and pushes and pulls the nozzle 44. The operator-side steering cable 54 includes a first end connected to the transmission gear 52 and a second end connected to the steering operator 60, and pushes and pulls the nozzle 44 via the second gear 52b and the nozzle-side steering cable 53. The nozzle-side steering cable 53 and the operator-side steering cable 54 are push-pull cables. The operator-side steering cable 54 also pushes and pulls the steering operator 60 when the electric motor 51 is driven. That is, when the electric motor 51 is driven, the steering operator 60 operates even when the watercraft operator does not operate the steering operator 60. The nozzle-side steering cable 53 is connected to a steering cable connector 44b of the nozzle 44. The nozzle 44 is rotated in the right-left direction by being pushed and pulled by the nozzle-side steering cable 53.

[0069] The trim actuator 55 shown in FIG. 9 includes an electric motor (not shown) as a drive source and a trim cable 55a to transmit the drive force of the electric motor to the nozzle 44. The trim actuator 55 uses the drive force of the electric motor to rotate the nozzle 44 in the upward-downward direction to change the orientation of the jet of water in the upward-downward direction. The trim actuator 55 is able to rotate the nozzle 44 in the upward-downward direction even when the jet of water is not being ejected. The trim cable 55a is connected to a trim cable connector 44c of the nozzle 44. The trim cable 55a is a push-pull cable. The trim actuator 55 is driven based on an operation on a trim operator 62.

[0070] The reverse actuator 56 shown in FIG. 10 includes an electric motor (not shown) as a drive source and a reverse cable 56a to transmit the drive force of the electric motor to the reverse bucket 45. The reverse actuator 56 uses the drive force of the electric motor to rotate the reverse bucket 45 in the upward-downward direction to change the orientation of the jet of water in the forward-rearward direction. The reverse cable 56a is connected to a reverse cable connector 45b of the reverse bucket 45. The reverse cable 56a is a push-pull cable.

[0071] As shown in FIG. 13, the operator 6 includes the steering operator 60, a throttle lever 61, and the trim operator 62.

[0072] The steering operator 60 includes a pair of bar-shaped grips provided on the right and left sides of the watercraft body 110. The drive force input from the watercraft operator to the steering operator 60 is transmitted to the nozzle 44 via the operator-side steering cable 54 shown in FIG. 12, the transmission gear 52, and the nozzle-side steering cable 53. Consequently, the nozzle 44 rotates in the right-left direction.

[0073] The throttle lever 61 shown in FIG. 13 increases or decreases the rotation speed of the impeller 42 (opening of a throttle valve of the engine 30) depending on the amount of operation. As the throttle lever 61 is gripped tighter, the amount of operation becomes larger, and thus the force of the jet of water increases. The throttle lever 61 includes a lever position sensor 63 to detect the amount of operation of the throttle lever 61.

[0074] Specifically, the throttle lever 61 includes a forward movement throttle lever 61a to move the watercraft body 110 forward, and a reverse movement throttle lever 61b to move the watercraft body 110 backward. The forward movement throttle lever 61a is provided along the right steering operator 60. The reverse movement throttle lever 61b is provided along the left steering operator 60. The lever position sensor 63 includes a forward movement lever position sensor 63a to detect the amount of operation of the forward movement throttle lever 61a, and a reverse movement lever position sensor 63b to detect the amount of operation of the reverse movement throttle lever 61b.

[0075] The trim operator 62 includes a trim-up button and a trim-down button. When the trim-up button is pressed, the nozzle 44 is rotated upward by the trim actuator 55. When the trim-down button is pressed, the nozzle 44 is rotated downward by the trim actuator 55.

[0076] As an example, the controller 8 shown in FIG. 1 includes an engine control unit (ECU), a shift control unit (SCU) to control shifting, a remote control unit (RCU) to control maneuvering in the wireless watercraft maneuvering mode, a steering actuator controller to perform a control to drive the steering actuator 50, etc. Alternatively, the controller may include an integrated control unit. The controller 8 includes a computer that includes a CPU, a ROM, a RAM, etc.

[0077] As described above, the controller 8 performs the oscillation control to repeatedly oscillate the nozzle 44 using the nozzle actuator 5a when the watercraft body 110 is launched from the trailer T. The controller 8 performs the oscillation control based on the oscillation signal I1 received from the remote control 2 via the communicator 1. The oscillation signal I1 is transmitted from the remote control 2 for the pressing duration in which the pressing operation continues.

[0078] Specifically, for a pressing duration in which a pressing operation on the oscillation button 23 of the remote control 2 continues, the controller 8 performs the oscillation control to oscillate the nozzle 44 using the nozzle actuator 5a based on the oscillation signal I1.

[0079] More specifically, for a pressing duration in which a pressing operation on the right-left oscillation button 23a continues, the controller 8 performs the oscillation control to oscillate the nozzle 44 in the right-left direction using the steering actuator 50. Furthermore, for a pressing duration in which a pressing operation on the upward-downward oscillation button 23b continues, the controller 8 oscillates the nozzle 44 in the upward-downward direction using the trim actuator 55 in the oscillation control.

[0080] While the oscillation control is performed (while the oscillation button 23 is pressed) and for a pressing duration in which a pressing operation on the stern float button 24 continues, the controller 8 is able to eject a jet of water in the direction (substantially directly below) that causes the stern 114 to float by directing the jetting port 44a of the nozzle 44 upward using the trim actuator 55 and adjusting the position of the reverse bucket 45 relative to the nozzle 44 to redirect the jet of water downward. Even when the oscillation control is not being performed, the controller 8 is able to eject a jet of water in the direction that causes the stern 114 to float by directing the jetting port 44a of the nozzle 44 upward using the trim actuator 55 and adjusting the position of the reverse bucket 45 relative to the nozzle 44 for the pressing duration in which the pressing operation on the stern float button 24 continues.

[0081] The controller 8 oscillates the nozzle 44 in the right-left direction within the maximum angular range in which the nozzle 44 is movable by the steering actuator 50 in the oscillation control. Furthermore, the controller 8 oscillates the nozzle 44 in the right-left direction with a period of 0.5 seconds or more and 4 seconds or less in the oscillation control, for example. The oscillation period of the nozzle 44 is set to be shorter as the size of the watercraft decreases.

[0082] The controller 8 controls driving of the electric motor 51 to push and pull the nozzle 44 via the nozzle-side steering cable 53 to perform the oscillation control to oscillate the nozzle 44 in the right-left direction. Furthermore, in the oscillation control, the controller 8 pushes and pulls the steering operator 60 via the operator-side steering cable 54 to oscillate the steering operator 60 as well.

[0083] When the watercraft body 110 is launched, the order in which the following actions are performed is determined by an operator of the remote control 2: generation of a reverse thrust by a jet of water from the jet propulsion mechanism 4, oscillation of the nozzle 44 in the right-left direction, oscillation of the nozzle 44 in the upward-downward direction, and floating of the stern 114 by a jet of water from the jet propulsion mechanism 4. These actions may be performed partially simultaneously or individually.

[0084] Normally, when the watercraft body 110 is launched, generation of a reverse thrust by a jet of water from the jet propulsion mechanism 4 is performed first. When launching of the watercraft body 110 is not able to be completed by a reverse thrust alone, one example of a subsequent operation is to oscillate the nozzle 44 in the right-left direction while the reverse thrust is still generated or after the reverse thrust is stopped. When launching of the watercraft body 110 is not able to be completed even by oscillating the nozzle 44 in the right-left direction, oscillation of the nozzle 44 in the upward-downward direction or floating of the stern 114 by a jet of water from the jet propulsion mechanism 4 is then performed. Oscillation of the nozzle 44 in the upward-downward direction and floating of the stern 114 by a jet of water from the jet propulsion mechanism 4 may be performed simultaneously with oscillation of the nozzle 44 in the right-left direction or may be performed after oscillation of the nozzle 44 in the right-left direction is stopped.

[0085] A control process flow for the oscillation control shown in FIG. 14 is now described. The oscillation control is performed by the controller 8. The oscillation control starts from a state in which the launching support mode is selected using the mode switching button 21 at the upper left of the screen of the remote control 2.

[0086] In step S1, it is determined whether or not a + button for the engine rotation speed of the watercraft body operation buttons 22 has been operated. When it is determined that the + button has been operated, the process advances to step S2, and when it is determined that the + button has not been operated, the process advances to step S3.

[0087] In step S2, a jet of water is ejected forward from the jet propulsion mechanism 4, and a reverse thrust of the magnitude set in step S1 is generated. Then, the process advances to step S3.

[0088] In step S3, it is determined whether or not the right-left oscillation button 23a of the remote control 2 has been operated. When it is determined that the right-left oscillation button 23a has been operated, the process advances to step S4, and when it is determined that the right-left oscillation button 23a has not been operated, the process advances to step S5.

[0089] In step S4, the steering actuator 50 is driven to oscillate the nozzle 44 in the right-left direction. The oscillation of the nozzle 44 in the right-left direction in step S4 is continuously performed only while a pressing operation on the right-left oscillation button 23a continues. Then, the process advances to step S5.

[0090] In step S5, it is determined whether or not the upward-downward oscillation button 23b of the remote control 2 has been operated. When it is determined that the upward-downward oscillation button 23b has been operated, the process advances to step S6, and when it is determined that the upward-downward oscillation button 23b has not been operated, the process advances to step S7.

[0091] In step S6, the trim actuator 55 is driven to oscillate the nozzle 44 in the upward-downward direction. Then, the process advances to step S7. The oscillation of the nozzle 44 in the upward-downward direction in step S6 is continuously performed only while a pressing operation on the upward-downward oscillation button 23b continues.

[0092] In step S7, it is determined whether or not the stern float button 24 of the remote control 2 has been operated. When it is determined that the stern float button 24 has been operated, the process advances to step S8, and when it is determined that the stern float button 24 has not been operated, the process advances to step S9.

[0093] In step S8, the orientations of the trim actuator 55 and the reverse bucket 45 are adjusted such that a jet of water is ejected in the direction (substantially directly below) that causes the stern 114 to float. Then, the process advances to step S9. The ejection of the jet of water in the direction that causes the stern 114 to float in step S8 is continuously performed only while a pressing operation on the stern float button 24 continues.

[0094] In step S9, it is determined whether or not the mode switching button 21 has been operated to exit the launching support mode. When it is determined that the launching support mode has been exited, the process advances to END. When it is determined that the launching support mode has not been exited, the process returns to step S1.

[0095] According to the various example embodiments of the present invention described above, the following advantageous effects are achieved.

[0096] According to an example embodiment of the present invention, the jet propulsion system 120 includes the controller 8 configured or programmed to perform the oscillation control to repeatedly oscillate the nozzle 44 using the nozzle actuator 5a when the watercraft body 110 is launched from the trailer T. Accordingly, when the watercraft body 110 is launched, the position of the watercraft body 110 relative to the trailer T is shifted by oscillating the watercraft body 110 such that the watercraft body 110 is released from friction with the trailer T at the same position. Therefore, even when it is difficult or impossible to move the watercraft body 110 in the launching direction by simply ejecting a jet of water forward, the watercraft body 110 is effectively moved in the launching direction by oscillating the nozzle 44. Consequently, the watercraft body 110 is easily launched from the trailer T.

[0097] According to an example embodiment of the present invention, the nozzle actuator 5a includes the steering actuator 50 to rotate the nozzle 44 in the right-left direction to change the orientation of the jet of water in the right-left direction, and the controller 8 is configured or programmed to perform the oscillation control to oscillate the nozzle 44 in the right-left direction using the steering actuator 50. Accordingly, the steering actuator 50 is controlled to easily oscillate the nozzle 44 repeatedly in the right-left direction. Consequently, a launching operation to launch the watercraft body 110 from the trailer T is performed more easily.

[0098] According to an example embodiment of the present invention, the jet propulsion system 120 further includes the remote control 2 to maneuver the watercraft body 110 by remote control, and the communicator 1 on the watercraft body 110 to communicate with the remote control 2, and the controller 8 is configured or programmed to perform the oscillation control based on the oscillation signal I1 received from the remote control 2 via the communicator 1. Accordingly, the remote control 2 enables a person not on board the watercraft body 110 to perform the oscillation control by operating the remote control 2.

[0099] According to an example embodiment of the present invention, the remote control 2 includes the oscillation button 23 to continuously transmit the oscillation signal I1 for the pressing duration in which the pressing operation continues, and the controller 8 is configured or programmed to perform the oscillation control to oscillate the nozzle 44 using the nozzle actuator 5a based on the oscillation signal I1 for the pressing duration. Accordingly, the oscillation button 23 enables the nozzle 44 to be oscillated to oscillate the watercraft body 110 only while an operator of the oscillation button 23 intentionally operates the oscillation button 23.

[0100] According to an example embodiment of the present invention, the remote control 2 is configured to receive an operation to move the watercraft body 110 to the predetermined boarding position after launching of the watercraft body 110 is completed. Accordingly, following the oscillation control to launch the watercraft body 110 by operating the remote control 2, the watercraft body 110 is able to be moved to the predetermined boarding position by operating the remote control 2 that has instructed the oscillation control.

[0101] According to an example embodiment of the present invention, the jet propulsion system 120 further includes the reverse bucket 45 to change the orientation of the jet of water in the forward-rearward direction, and the controller 8 is configured or programmed to generate a backward propulsive force using the reverse bucket 45 while performing the oscillation control. Accordingly, the reverse bucket 45 generates a backward propulsive force simultaneously with oscillating the nozzle 44, and thus the launching operation to launch the watercraft body 110 from the trailer T is performed more easily as compared with a case in which oscillating the nozzle 44 and generating a backward propulsive force using the reverse bucket 45 are performed separately.

[0102] According to an example embodiment of the present invention, the jet propulsion system 120 further includes the reverse bucket 45 to change the orientation of the jet of water in the forward-rearward direction, the nozzle actuator 5a includes the trim actuator 55 to rotate the nozzle 44 in the upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller 8 is configured or programmed to, while performing the oscillation control, eject the jet of water in the direction that causes the stern 114 to float by directing the jetting port 44a of the nozzle 44 upward using the trim actuator 55 and adjusting the position of the reverse bucket 45 relative to the nozzle 44 to redirect the jet of water downward. Accordingly, the jet of water, the orientation of which has been adjusted by the trim actuator 55 and the reverse bucket 45, enables the nozzle 44 to be oscillated while the stern 114 is floated higher in the water. That is, the nozzle 44 is oscillated in a state in which a contact area between the trailer T and the watercraft body 110 is reduced to reduce friction. Consequently, the launching operation to launch the watercraft body 110 from the trailer T is performed more easily.

[0103] According to an example embodiment of the present invention, the controller 8 is configured or programmed to oscillate the nozzle 44 in the right-left direction within the maximum angular range in which the nozzle 44 is movable by the steering actuator 50 in the oscillation control. Accordingly, the nozzle 44 is oscillated in the right-left direction within the maximum angular range such that a large oscillation is imparted to the watercraft body 110, and thus the launching operation to launch the watercraft body 110 from the trailer T is performed even more easily.

[0104] According to an example embodiment of the present invention, the controller 8 is configured or programmed to oscillate the nozzle 44 in the right-left direction with a period of 0.5 seconds or more and 4 seconds or less in the oscillation control. Accordingly, the watercraft body 110 is effectively oscillated by oscillating the nozzle 44 in the right-left direction with a short period of 0.5 seconds or more and 4 seconds or less, for example.

[0105] According to an example embodiment of the present invention, the steering actuator 50 includes the electric motor 51, the transmission gear 52 to transmit the drive force of the electric motor 51 to the nozzle 44, and the nozzle-side steering cable 53 including the first end connected to the transmission gear 52 and the second end connected to the nozzle 44 to push and pull the nozzle 44, and the controller 8 is configured or programmed to control driving of the electric motor 51 to push and pull the nozzle 44 via the nozzle-side steering cable 53 to perform the oscillation control to oscillate the nozzle 44 in the right-left direction. Accordingly, the drive force of the electric motor 51 is transmitted to the nozzle 44 via the transmission gear 52 and the nozzle-side steering cable 53 to easily oscillate the nozzle 44 in the right-left direction.

[0106] According to an example embodiment of the present invention, the steering actuator 50 further includes the operator-side steering cable 54 including the first end connected to the transmission gear 52 and the second end connected to the steering operator 60 to push and pull the steering operator 60, and the controller 8 is configured or programmed to push and pull the steering operator 60 via the operator-side steering cable 54 to oscillate the steering operator 60 as well in the oscillation control. Accordingly, the watercraft body 110 is oscillated by not only the nozzle 44 but also the steering operator 60, and thus a larger oscillation is imparted to the watercraft body 110.

[0107] According to an example embodiment of the present invention, the nozzle actuator 5a includes the trim actuator 55 to rotate the nozzle 44 in the upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller 8 is configured or programmed to oscillate the nozzle 44 in the upward-downward direction using the trim actuator 55 in the oscillation control. Accordingly, the nozzle 44 is easily oscillated repeatedly in the upward-downward direction by the trim actuator 55. Consequently, the launching operation to launch the watercraft body 110 from the trailer T is performed more easily.

[0108] The example embodiments of the present invention described above are illustrative in all points and not restrictive. The extent of the present invention is not defined by the above description of the example embodiments but by the scope of the claims, and all modifications within the meaning and range equivalent to the scope of the claims are further included.

[0109] For example, while the jet propulsion watercraft is preferably a so-called jet ski or jet bike in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the jet propulsion watercraft may alternatively be a so-called jet-propelled sports boat.

[0110] While the jet drive source preferably includes an engine as a drive source to rotate the impeller in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the jet drive source may alternatively include an electric motor as a drive source to rotate the impeller.

[0111] While when the watercraft body is launched, the order in which the following actions are performed is preferably determined by the operator of the remote control: generation of a reverse thrust by a jet of water from the jet propulsion mechanism, oscillation of the nozzle in the right-left direction, oscillation of the nozzle in the upward-downward direction, and floating of the stern by a jet of water from the jet propulsion mechanism in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the order in which the following actions are performed may alternatively be determined in advance: generation of a reverse thrust by a jet of water from the jet propulsion mechanism, oscillation of the nozzle in the right-left direction, oscillation of the nozzle in the upward-downward direction, and floating of the stern by a jet of water from the jet propulsion mechanism, and the controller may alternatively perform the actions in this order. In such a case, switching between the actions may be performed at predetermined time intervals, or the operator of the remote control may operate a predetermined switching button to switch between the actions, for example.

[0112] While the remote control preferably includes the oscillation button in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the watercraft body may alternatively include the oscillation button. That is, the oscillation button may alternatively be provided on the watercraft body.

[0113] While the remote control preferably includes the stern float button in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the watercraft body may alternatively include the stern float button. That is, the stern float button may alternatively be provided on the watercraft body.

[0114] While the nozzle is preferably oscillated in the right-left direction within the maximum angular range in which the nozzle is movable in the oscillation control in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the nozzle may alternatively be oscillated in the right-left direction within an angular range smaller than the maximum angular range described above in the oscillation control.

[0115] While the steering actuator preferably oscillates the steering operator as well when oscillating the nozzle in the right-left direction in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the steering actuator may not oscillate the steering operator when oscillating the nozzle in the right-left direction.

[0116] While the steering actuator is preferably driven by the electric motor in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the steering actuator may alternatively be driven by a cylinder or a solenoid, for example.

[0117] While the process operations performed by the controller are described using a flowchart in a flow-driven manner in which processes are performed in order along a process flow for the convenience of illustration in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the process operations performed by the controller may alternatively be performed in an event-driven manner in which the processes are performed on an event basis. In this case, the process operations performed by the controller may be performed in a complete event-driven manner or in a combination of an event-driven manner and a flow-driven manner.

[0118] While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Examples

Embodiment Construction

[0045]Example embodiments of the present invention are hereinafter described with reference to the drawings.

[0046]Jet propulsion watercrafts 100 according to example embodiments of the present invention are now described with reference to FIGS. 1 to 14.

[0047]The jet propulsion watercraft 100 shown in FIGS. 1 and 2 is a personal watercraft, for example, and sails with a relatively small number of people on board. The jet propulsion watercraft 100 is a so-called jet ski or jet bike that glides on the surface of the water. The jet propulsion watercraft 100 includes a watercraft body 110 and a jet propulsion system 120 mounted on the watercraft body 110. The watercraft body 110 includes a hull 111 that defines the bottom of the watercraft, a deck 112 located above the hull 111, and a seat 113 located at the center of the deck 112 in a right-left direction.

[0048]As shown in FIG. 3, the jet propulsion system 120 includes a communicator 1, a remote control 2, a jet drive source 3, a jet pr...

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to Japanese Patent Application No. 2024-197827 filed on Nov. 13, 2024. The entire contents of this application are hereby incorporated herein by reference.BACKGROUND OF THE INVENTION1. Field of the Invention

[0002] The present invention relates to jet propulsion systems, jet propulsion watercrafts, and watercraft body launching methods.2. Description of the Related Art

[0003] A jet propulsion watercraft including a jet propulsion mechanism is known in general. Such a jet propulsion watercraft is disclosed in Japanese Patent Laid-Open No. 2011-189847, for example.

[0004] Japanese Patent Laid-Open No. 2011-189847 discloses a jet propulsion watercraft including a jet propulsion mechanism. The jet propulsion watercraft ejects a jet of water forward from the jet propulsion mechanism to generate a backward propulsive force for backward movement when a watercraft body is launched from a trailer.

[0005] However, in the jet propulsion watercraft described in Japanese Patent Laid-Open No. 2011-189847, simply repeatedly applying, to the watercraft body, a linear thrust in a launching direction in which the watercraft body is launched by ejecting a jet of water forward from the jet propulsion mechanism may not be enough to or may be unlikely to move the watercraft body in the launching direction, depending on the magnitude of a frictional resistance between the watercraft body and the trailer. In such a case, a launching operation may take a lot of time and effort. Therefore, it is desired to facilitate the launching operation to launch the watercraft body from the trailer.SUMMARY OF THE INVENTION

[0006] Example embodiments of the present invention provide jet propulsion systems, jet propulsion watercrafts, and watercraft body launching methods that each facilitate launching operations to launch watercraft bodies.

[0007] A jet propulsion system according to an example embodiment of the present invention includes a jet propulsion mechanism located at a stern of a watercraft body including a nozzle including a jetting port to eject a jet of water to generate a propulsive force, a nozzle actuator to rotate the nozzle to change an orientation of the jet of water from the jetting port, and a controller configured or programmed to perform an oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched.

[0008] A jet propulsion system according to an example embodiment of the present invention includes the controller configured or programmed to perform the oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched. Accordingly, when the watercraft body is launched, the position of the watercraft body is shifted by oscillating the watercraft body such that the watercraft body is released from friction with a trailer. Therefore, even when it is difficult or impossible to move the watercraft body in the launching direction by simply ejecting a jet of water forward, the watercraft body is effectively moved in the launching direction by oscillating the nozzle. Consequently, the watercraft body is easily launched.

[0009] In a jet propulsion system according to an example embodiment of the present invention, the nozzle actuator preferably includes a steering actuator to rotate the nozzle in a right-left direction to change the orientation of the jet of water in the right-left direction, and the controller is preferably configured or programmed to perform the oscillation control to oscillate the nozzle in the right-left direction using the steering actuator. Accordingly, the steering actuator is controlled to easily oscillate the nozzle repeatedly in the right-left direction. Consequently, a launching operation to launch the watercraft body is performed more easily.

[0010] A jet propulsion system according to an example embodiment of the present invention preferably further includes a remote control to maneuver the watercraft body by remote control, and a communicator on the watercraft body to communicate with the remote control, and the controller is preferably configured or programmed to perform the oscillation control based on an oscillation signal received from the remote control via the communicator. Accordingly, the remote control enables a person not on board the watercraft body to perform the oscillation control by operating the remote control.

[0011] In such a case, the remote control preferably includes an oscillation button to continuously transmit the oscillation signal for a pressing duration in which a pressing operation continues, and the controller is preferably configured or programmed to perform the oscillation control to oscillate the nozzle using the nozzle actuator based on the oscillation signal for the pressing duration. Accordingly, the oscillation button enables the nozzle to be oscillated to oscillate the watercraft body only while an operator of the oscillation button intentionally operates the oscillation button.

[0012] In a jet propulsion system including the remote control and the communicator, the remote control is preferably configured to receive an operation to move the watercraft body to a predetermined boarding position after launching of the watercraft body is completed. Accordingly, following the oscillation control to launch the watercraft body by operating the remote control, the watercraft body is able to be moved to the predetermined boarding position by operating the remote control that has instructed the oscillation control.

[0013] A jet propulsion system according to an example embodiment of the present invention preferably further includes a reverse bucket to change the orientation of the jet of water in a forward-rearward direction, and the controller is preferably configured or programmed to generate a backward propulsive force using the reverse bucket while performing the oscillation control. Accordingly, the reverse bucket generates a backward propulsive force simultaneously with oscillating the nozzle, and thus the launching operation to launch the watercraft body is performed more easily as compared with a case in which oscillating the nozzle and generating a backward propulsive force using the reverse bucket are performed separately.

[0014] A jet propulsion system according to an example embodiment of the present invention preferably further includes a reverse bucket to change the orientation of the jet of water in a forward-rearward direction, the nozzle actuator preferably includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller is preferably configured or programmed to, while performing the oscillation control, eject the jet of water in a direction that causes the stern to float by directing the jetting port of the nozzle upward using the trim actuator and adjusting a position of the reverse bucket relative to the nozzle to redirect the jet of water downward. Accordingly, the jet of water, the orientation of which has been adjusted by the trim actuator and the reverse bucket, enables the nozzle to be oscillated while the stern is floated higher in the water. That is, the nozzle is oscillated in a state in which a contact area between the trailer and the watercraft body is reduced to reduce friction. Consequently, the launching operation to launch the watercraft body is performed more easily.

[0015] In a jet propulsion system including the controller configured or programmed to perform the oscillation control using the steering actuator, the controller is preferably configured or programmed to oscillate the nozzle in the right-left direction within a maximum angular range in which the nozzle is movable by the steering actuator in the oscillation control. Accordingly, the nozzle is oscillated in the right-left direction within the maximum angular range such that a large oscillation is imparted to the watercraft body, and thus the launching operation to launch the watercraft body is performed even more easily.

[0016] In a jet propulsion system including the controller configured or programmed to perform the oscillation control using the steering actuator, the controller is preferably configured or programmed to oscillate the nozzle in the right-left direction with a period of, for example, 0.5 seconds or more and 4 seconds or less in the oscillation control. Accordingly, the watercraft body is effectively oscillated by oscillating the nozzle in the right-left direction with a short period of 0.5 seconds or more and 4 seconds or less, for example.

[0017] In a jet propulsion system including the controller configured or programmed to perform the oscillation control using the steering actuator, the steering actuator preferably includes an electric motor, a transmission gear to transmit a drive force of the electric motor to the nozzle, and a nozzle-side steering cable including a first end connected to the transmission gear and a second end connected to the nozzle to push and pull the nozzle, and the controller is preferably configured or programmed to control driving of the electric motor to push and pull the nozzle via the nozzle-side steering cable to perform the oscillation control to oscillate the nozzle in the right-left direction. Accordingly, the drive force of the electric motor is transmitted to the nozzle via the transmission gear and the nozzle-side steering cable to easily oscillate the nozzle in the right-left direction.

[0018] In such a case, the steering actuator preferably further includes an operator-side steering cable including a first end connected to the transmission gear and a second end connected to a steering operator to push and pull the steering operator, and the controller is preferably configured or programmed to push and pull the steering operator via the operator-side steering cable to also oscillate the steering operator in the oscillation control. Accordingly, the watercraft body is oscillated by not only the nozzle but also the steering operator, and thus a larger oscillation is imparted to the watercraft body.

[0019] In a jet propulsion system according to an example embodiment of the present invention, the nozzle actuator preferably includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller is preferably configured or programmed to oscillate the nozzle in the upward-downward direction using the trim actuator in the oscillation control. Accordingly, the nozzle is easily oscillated repeatedly in the upward-downward direction by the trim actuator. Consequently, the launching operation to launch the watercraft body is performed more easily.

[0020] A jet propulsion watercraft according to an example embodiment of the present invention includes a watercraft body, a jet propulsion mechanism located at a stern of the watercraft body including a nozzle including a jetting port to eject a jet of water to generate a propulsive force, a nozzle actuator to rotate the nozzle to change an orientation of the jet of water from the jetting port, and a controller configured or programmed to perform an oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched.

[0021] A jet propulsion watercraft according to an example embodiment of the present invention includes the controller configured or programmed to perform the oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched. Accordingly, when the watercraft body is launched, the position of the watercraft body is shifted by oscillating the watercraft body such that the watercraft body is released from friction with a trailer. Therefore, even when it is difficult or impossible to move the watercraft body in the launching direction by simply ejecting a jet of water forward, the watercraft body is effectively moved in the launching direction by oscillating the nozzle. Consequently, the watercraft body is easily launched.

[0022] In a jet propulsion watercraft according to an example embodiment of the present invention, the nozzle actuator preferably includes a steering actuator to rotate the nozzle in a right-left direction to change the orientation of the jet of water in the right-left direction, and the controller is preferably configured or programmed to perform the oscillation control to oscillate the nozzle in the right-left direction using the steering actuator. Accordingly, the steering actuator is controlled to easily oscillate the nozzle repeatedly in the right-left direction. Consequently, a launching operation to launch the watercraft body is performed more easily.

[0023] A jet propulsion watercraft according to an example embodiment of the present invention preferably further includes a communicator to communicate with a remote control configured or programmed to maneuver the watercraft body by remote control, and the controller is preferably configured or programmed to perform the oscillation control based on an oscillation signal received from the remote control via the communicator. Accordingly, the remote control enables a person not on board the watercraft body to perform the oscillation control by operating the remote control.

[0024] In a jet propulsion watercraft including the remote control and the communicator, the remote control preferably includes an oscillation button to continuously transmit the oscillation signal for a pressing duration in which a pressing operation continues, and the controller is preferably configured or programmed to perform the oscillation control to oscillate the nozzle using the nozzle actuator based on the oscillation signal for the pressing duration. Accordingly, the oscillation button enables the nozzle to be oscillated to oscillate the watercraft body only while an operator of the oscillation button intentionally operates the oscillation button.

[0025] In a jet propulsion watercraft according to an example embodiment of the present invention, the remote control is preferably configured to receive an operation to move the watercraft body to a predetermined boarding position after launching of the watercraft body is completed. Accordingly, following the oscillation control to launch the watercraft body by operating the remote control, the watercraft body is able to be moved to the predetermined boarding position by operating the remote control that has instructed the oscillation control.

[0026] A jet propulsion watercraft according to an example embodiment of the present invention preferably further includes a reverse bucket to change the orientation of the jet of water in a forward-rearward direction, and the controller is preferably configured or programmed to generate a backward propulsive force using the reverse bucket while performing the oscillation control. Accordingly, the reverse bucket generates a backward propulsive force simultaneously with oscillating the nozzle, and thus the launching operation to launch the watercraft body is performed more easily as compared with a case in which oscillating the nozzle and generating a backward propulsive force using the reverse bucket are performed separately.

[0027] A jet propulsion watercraft according to an example embodiment of the present invention preferably further includes a reverse bucket to change the orientation of the jet of water in a forward-rearward direction, the nozzle actuator preferably includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller is preferably configured or programmed to, while performing the oscillation control, eject the jet of water in a direction that causes the stern to float by directing the jetting port of the nozzle upward using the trim actuator and adjusting a position of the reverse bucket relative to the nozzle to redirect the jet of water downward. Accordingly, the jet of water, the orientation of which has been adjusted by the trim actuator and the reverse bucket, enables the nozzle to be oscillated while the stern is floated higher in the water. That is, the nozzle is oscillated in a state in which a contact area between the trailer and the watercraft body is reduced to reduce friction. Consequently, the launching operation to launch the watercraft body from the trailer is performed more easily.

[0028] A watercraft body launching method according to an example embodiment of the present invention includes generating a backward propulsive force using a jet of water from a jetting port of a nozzle of a jet propulsion mechanism when a watercraft body is launched from a trailer, and repeatedly oscillating the nozzle when the watercraft body is launched from the trailer.

[0029] A watercraft body launching method according to an example embodiment of the present invention includes repeatedly oscillating the nozzle when the watercraft body is launched from the trailer. Accordingly, when the watercraft body is launched, the position of the watercraft body relative to the trailer is shifted by oscillating the watercraft body such that the watercraft body is released from friction with the trailer. Therefore, even when it is difficult or impossible to move the watercraft body in the launching direction by simply ejecting a jet of water forward, the watercraft body is effectively moved in the launching direction by oscillating the nozzle. Consequently, the watercraft body is easily launched from the trailer.

[0030] The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a side view showing a jet propulsion watercraft on which a jet propulsion system is mounted according to an example embodiment of the present invention.

[0032] FIG. 2 is an enlarged side view showing a portion of a jet propulsion watercraft on which a jet propulsion system is mounted according to an example embodiment of the present invention.

[0033] FIG. 3 is a block diagram of a jet propulsion system according to an example embodiment of the present invention.

[0034] FIG. 4 is a side view illustrating an arrangement of a trailer and a jet propulsion watercraft when a launching operation is performed.

[0035] FIG. 5 is a plan view showing a state in which an oscillation control is performed by a controller of a jet propulsion system according to an example embodiment of the present invention.

[0036] FIG. 6 is a diagram showing a jet propulsion watercraft according to an example embodiment of the present invention and a remote control that wirelessly communicates with the jet propulsion watercraft.

[0037] FIG. 7 is a diagram showing a display screen of a remote control of a jet propulsion system according to an example embodiment of the present invention.

[0038] FIG. 8 is a schematic plan view illustrating right and left rotation of a nozzle of a jet propulsion mechanism of a jet propulsion system according to an example embodiment of the present invention.

[0039] FIG. 9 is a schematic side view illustrating upward and downward rotation (trim) of a nozzle of a jet propulsion mechanism according to an example embodiment of the present invention.

[0040] FIG. 10 is a schematic side view illustrating upward and downward rotation of a reverse bucket of a jet propulsion mechanism according to an example embodiment of the present invention.

[0041] FIG. 11 is a side view illustrating the orientations of a nozzle and a reverse bucket when a stern is lifted.

[0042] FIG. 12 is a partial enlarged view of a portion A in FIG. 2.

[0043] FIG. 13 is a diagram showing an operator according to an example embodiment of the present invention from the rear side.

[0044] FIG. 14 is a flowchart of a control process for an oscillation control according to an example embodiment of the present invention.DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

[0045] Example embodiments of the present invention are hereinafter described with reference to the drawings.

[0046] Jet propulsion watercrafts 100 according to example embodiments of the present invention are now described with reference to FIGS. 1 to 14.

[0047] The jet propulsion watercraft 100 shown in FIGS. 1 and 2 is a personal watercraft, for example, and sails with a relatively small number of people on board. The jet propulsion watercraft 100 is a so-called jet ski or jet bike that glides on the surface of the water. The jet propulsion watercraft 100 includes a watercraft body 110 and a jet propulsion system 120 mounted on the watercraft body 110. The watercraft body 110 includes a hull 111 that defines the bottom of the watercraft, a deck 112 located above the hull 111, and a seat 113 located at the center of the deck 112 in a right-left direction.

[0048] As shown in FIG. 3, the jet propulsion system 120 includes a communicator 1, a remote control 2, a jet drive source 3, a jet propulsion mechanism 4 including a nozzle 44 (see FIG. 1) to eject a jet of water, an actuator 5 to change the orientation of the jet of water, an operator 6, a GPS receiver 7, and a controller 8. The actuator 5 includes a steering actuator 50 and a trim actuator 55 to drive the nozzle 44, and a reverse actuator 56 to drive a reverse bucket 45. The steering actuator 50 and the trim actuator 55 are nozzle actuators 5a that rotate the nozzle 44 to change the orientation of the jet of water from a jetting port 44a.

[0049] In the figures, an X direction represents the forward-rearward direction of the jet propulsion watercraft 100. In the X direction, an X1 direction (FRD) represents a forward movement direction, and an X2 direction (BWD) represents a reverse movement direction. In the figures, a Y direction represents the right-left direction of the jet propulsion watercraft 100. In the figures, a Z direction represents the upward-downward direction of the jet propulsion watercraft 100, a Z1 direction represents an upward direction, and a Z2 direction represents a downward direction.

[0050] The jet propulsion system 120 (controller 8) according to an example embodiment of the present invention shown in FIGS. 4 and 5 performs an oscillation control to repeatedly oscillate the nozzle 44 using the nozzle actuators 5a when the watercraft body 110 is launched from a trailer T. In principle, the oscillation control is performed when no one is on board the watercraft body 110. The oscillation control is described below in detail.

[0051] The trailer T carrying the watercraft body 110 is positioned by a vehicle V towing the trailer T to touch the water surface from the land side. The position at which the trailer T touches the water surface is a sloping surface K that is lower on the trailer T side than on the vehicle V side. At this time, a water intake 40a in a lower portion of the watercraft body 110 is located underwater such that water is able to be taken into a water passage 40 (see FIG. 1). When the watercraft body 110 is launched, the trailer T has an inverted U-shape in a plan view, with the stern 114 side (X2 direction side) open. The trailer T includes a pair of watercraft body supports T1 extending in the forward-rearward direction of the watercraft body 110 and aligned in the right-left direction of the watercraft body 110. The watercraft body 110 is placed from above on the pair of watercraft body supports T1. The watercraft body 110 is located between the pair of watercraft body supports T1.

[0052] The communicator 1 shown in FIG. 3 is provided on the watercraft body 110. The communicator 1 establishes wireless communication with the remote control 2. As an example, the communicator 1 establishes wireless communication with the remote control 2 via Bluetooth (registered trademark). The communicator is not limited to Bluetooth and may be a wireless communicator using other communication standards, such as Wi-Fi (registered trademark). A watercraft operator causes the remote control 2 to establish wireless communication with the communicator 1 as preparations to travel on the jet propulsion watercraft 100 (see FIG. 6).

[0053] The remote control 2 is held by the watercraft operator of the jet propulsion watercraft 100, or by a watercraft maneuvering assistant. As an example, the remote control 2 is a smartphone. The remote control is not limited to a smartphone and may be a dedicated communication device to wirelessly communicate with the jet propulsion watercraft or a tablet terminal, for example. A dedicated application is installed in the remote control 2 to establish communication with the jet propulsion watercraft 100.

[0054] The remote control 2 is a device to instruct movement of the watercraft body 110 by wireless communication with the watercraft body 110. A wireless watercraft maneuvering mode in which movement of the watercraft body 110 is instructed by the remote control 2 includes the following two modes: a remote watercraft maneuvering mode and an automatic movement mode.

[0055] In the remote watercraft maneuvering mode, the watercraft body 110 is remotely operated using the remote control 2. When “remote watercraft maneuvering” of mode switching buttons 21 at the upper left of a display screen 20 (see FIG. 7) of the dedicated application of the remote control 2 is selected, the mode switches to the remote watercraft maneuvering mode. When “normal” of the mode switching buttons 21 is selected, the mode switches to a normal mode in which the watercraft operator operates a steering operator 60 to maneuver the jet propulsion watercraft 100. In the remote watercraft maneuvering mode, the jet propulsion watercraft 100 is freely remotely controlled to move using watercraft body operation buttons 22 (such as a forward (F) button, a reverse (R) button, and right and left turn buttons at the center of the screen) on the display screen 20.

[0056] In the automatic movement mode, the watercraft body 110 is automatically moved by remotely instructing the watercraft body 110 to move automatically using the remote control 2. The automatic movement mode includes modes such as automatic return, fixed point holding, and launching support. The launching support is a mode in which the oscillation control described above is performed.

[0057] As shown in FIG. 7, the remote control 2 includes an oscillation button 23 used for the oscillation control in the launching support mode. The oscillation button 23 is displayed at a lower portion of the display screen 20 when the launching support is selected. The oscillation button 23 continuously transmits an oscillation signal I1 to the controller 8 to cause the nozzle 44 to oscillate for a pressing duration in which a pressing operation continues. The oscillation button 23 includes a right-left oscillation button 23a to repeatedly oscillate the nozzle 44 in the right-left direction, and an upward-downward oscillation button 23b to repeatedly oscillate the nozzle 44 in the upward-downward direction.

[0058] The remote control 2 also includes a stern float button 24 used during launching support. The stern float button 24 is pressed to eject a jet of water in a direction i.e., substantially directly below (see FIG. 11), that causes the stern 114 to float higher in the water, for the pressing duration in which the pressing operation continues. The stern float button 24 continuously transmits a stern float signal I2 (see FIG. 3) to the controller 8 to cause a jet of water to be ejected in the direction that causes the stern 114 to float for the pressing duration in which the pressing operation continues. As shown in FIG. 11, while the oscillation control is performed, the controller 8 is able to eject a jet of water in the direction (substantially directly below) that causes the stern 114 to float by directing the jetting port 44a of the nozzle 44 upward using the trim actuator 55 (see FIG. 9) and adjusting the position of the reverse bucket 45 relative to the nozzle 44 to redirect the jet of water downward. That is, while the oscillation button 23 is pressed, the stern float button 24 is also pressed to eject a jet of water in the direction that causes the stern 114 to float. Even when the oscillation button 23 is not being pressed, the stern float button 24 is pressed to eject a jet of water in the direction that causes the stern 114 to float.

[0059] The remote control 2 receives an operation to move the watercraft body 110 to a predetermined boarding position after launching of the watercraft body 110 is completed. Such an operation is performed, for example, by pressing the watercraft body operation buttons 22 of the remote control 2 after launching support is switched to the remote watercraft maneuvering mode by pressing the mode switching button 21.

[0060] As shown in FIG. 1, the jet drive source 3 includes an engine 30, a crankshaft 31, and a coupling 32. The engine 30 is, for example, a multi-cylinder internal combustion engine. The crankshaft 31 is an output shaft to output a torque generated by the engine 30. The crankshaft 31 extends rearward from the engine 30. The coupling 32 is provided at the rear end of the crankshaft 31 and connects and fixes the crankshaft 31 to an impeller shaft 41 of the jet propulsion mechanism 4.

[0061] The jet propulsion mechanism 4 generates a propulsive force by ejecting a jet of water from the jetting port 44a of the nozzle 44. The jet propulsion mechanism 4 includes the water passage 40, the impeller shaft 41, an impeller 42, a nozzle 43 fixed to the rear end of the water passage 40, the nozzle 44 drivably installed on the nozzle 43, and the reverse bucket (reverse gate) 45.

[0062] The water passage 40 extends from the lower portion of the watercraft body 110 toward the stern 114. Water is taken into the water passage 40 through the water intake 40a in the lower portion of the watercraft body 110. The impeller shaft 41 extending rearward is provided in the water passage 40. The impeller 42 is fixed to the impeller shaft 41. The impeller 42 rotates integrally with the impeller shaft 41 to generate a rearward flow. The impeller shaft 41 is connected to the crankshaft 31 via the coupling 32. Therefore, the rotation speed of the impeller 42 increases or decreases as the rotation speed of the engine 30 increases or decreases.

[0063] The nozzle 43 shown in FIG. 8 performs a function to jet water flowing through the water passage 40 toward the rear nozzle 44. The nozzle 44 is attached to the nozzle 43 from the rear. The nozzle 44 is located at the stern 114 of the watercraft body 110. The nozzle 44 includes the jetting port 44a for ejecting or jetting a jet of water. The nozzle 44 functions as a deflector to change the orientation of the jet of water ejected from the jetting port 44a. Specifically, the nozzle 44 is attached to the nozzle 43 so as to be rotatable in the right-left direction around a central axis C1 of an upward-downward central shaft 46 extending in the upward-downward direction (the steering position is adjustable around the upward-downward central shaft 46). The central axis C1 is located at the center of the nozzle 44 in the right-left direction. The nozzle 44 is rotated in the right-left direction by the steering actuator 50.

[0064] The nozzle 44 shown in FIG. 9 is attached to the nozzle 43 so as to be rotatable in the upward-downward direction around a central axis C2 of a right-left central shaft 47 extending in the right-left direction (the trim position is adjustable around the right-left central shaft 47). The central axis C2 is located at the center of the nozzle 44 in the upward-downward direction. The nozzle 44 is rotated in the upward-downward direction by the trim actuator 55. Thus, the nozzle 44 is rotated in the upward-downward direction and the right-left direction such that the orientation of the jet of water ejected from the jetting port 44a changes.

[0065] The reverse bucket 45 shown in FIG. 10 changes the orientation of the jet of water in the forward-rearward direction. The reverse bucket 45 rotationally moves between a position above the nozzle 44 and a position behind the nozzle 44. When moving to the position behind the nozzle 44, the reverse bucket 45 covers the jetting port 44a from behind such that the jet of water is directed forward, and the orientation of the jet of water is changed forward. The reverse bucket 45 is rotatable in the upward-downward direction around a central axis C3 of a right-left central shaft 48 extending in the right-left direction. The reverse bucket 45 is rotated in the upward-downward direction by the reverse actuator 56. Depending on the position of the reverse bucket 45, the jet propulsion watercraft 100 switches between a forward movement state, a reverse movement state, and a neutral state in which a forward thrust and a reverse thrust are substantially equal to each other. The jet propulsion watercraft 100 is in the reverse movement or neutral state when the reverse bucket 45 covers the jetting port 44a from behind, and is in the forward movement state when the reverse bucket 45 does not cover the jetting port 44a from behind. The reverse bucket 45 includes, on both the right and left sides thereof, jetting openings 45a each having a substantially cylindrical shape with a central axis directed diagonally forward to the right of the watercraft body 110.

[0066] Referring to FIGS. 2 and 12, the steering actuator 50 includes an electric motor 51 as a drive source, a transmission gear 52 to transmit the drive forces of the electric motor 51 and the steering operator 60 to the nozzle 44, a nozzle-side steering cable 53, and an operator-side steering cable 54. In the wireless watercraft maneuvering mode, the steering actuator 50 uses the drive force of the electric motor 51 to rotate the nozzle 44 in the right-left direction to change the orientation of the jet of water from the jetting port 44a in the right-left direction. The steering actuator 50 is able to rotate the nozzle 44 in the right-left direction even when the jet of water is not being ejected.

[0067] The electric motor 51 includes a motor shaft 51a, a transmission shaft 51b, and a clutch 51c to switch a connection state between the motor shaft 51a and the transmission shaft 51b. The jet propulsion watercraft may not include a clutch. A bevel gear 51d is provided on the side of the transmission shaft 51b opposite to the clutch 51c.

[0068] The transmission gear 52 includes a first gear 52a including a bevel gear 521 to mesh with the bevel gear 51d and a pinion 522, and a second gear 52b including a rack to mesh with the pinion 522. The nozzle-side steering cable 53 includes a first end connected to the transmission gear 52 and a second end connected to the nozzle 44, and pushes and pulls the nozzle 44. The operator-side steering cable 54 includes a first end connected to the transmission gear 52 and a second end connected to the steering operator 60, and pushes and pulls the nozzle 44 via the second gear 52b and the nozzle-side steering cable 53. The nozzle-side steering cable 53 and the operator-side steering cable 54 are push-pull cables. The operator-side steering cable 54 also pushes and pulls the steering operator 60 when the electric motor 51 is driven. That is, when the electric motor 51 is driven, the steering operator 60 operates even when the watercraft operator does not operate the steering operator 60. The nozzle-side steering cable 53 is connected to a steering cable connector 44b of the nozzle 44. The nozzle 44 is rotated in the right-left direction by being pushed and pulled by the nozzle-side steering cable 53.

[0069] The trim actuator 55 shown in FIG. 9 includes an electric motor (not shown) as a drive source and a trim cable 55a to transmit the drive force of the electric motor to the nozzle 44. The trim actuator 55 uses the drive force of the electric motor to rotate the nozzle 44 in the upward-downward direction to change the orientation of the jet of water in the upward-downward direction. The trim actuator 55 is able to rotate the nozzle 44 in the upward-downward direction even when the jet of water is not being ejected. The trim cable 55a is connected to a trim cable connector 44c of the nozzle 44. The trim cable 55a is a push-pull cable. The trim actuator 55 is driven based on an operation on a trim operator 62.

[0070] The reverse actuator 56 shown in FIG. 10 includes an electric motor (not shown) as a drive source and a reverse cable 56a to transmit the drive force of the electric motor to the reverse bucket 45. The reverse actuator 56 uses the drive force of the electric motor to rotate the reverse bucket 45 in the upward-downward direction to change the orientation of the jet of water in the forward-rearward direction. The reverse cable 56a is connected to a reverse cable connector 45b of the reverse bucket 45. The reverse cable 56a is a push-pull cable.

[0071] As shown in FIG. 13, the operator 6 includes the steering operator 60, a throttle lever 61, and the trim operator 62.

[0072] The steering operator 60 includes a pair of bar-shaped grips provided on the right and left sides of the watercraft body 110. The drive force input from the watercraft operator to the steering operator 60 is transmitted to the nozzle 44 via the operator-side steering cable 54 shown in FIG. 12, the transmission gear 52, and the nozzle-side steering cable 53. Consequently, the nozzle 44 rotates in the right-left direction.

[0073] The throttle lever 61 shown in FIG. 13 increases or decreases the rotation speed of the impeller 42 (opening of a throttle valve of the engine 30) depending on the amount of operation. As the throttle lever 61 is gripped tighter, the amount of operation becomes larger, and thus the force of the jet of water increases. The throttle lever 61 includes a lever position sensor 63 to detect the amount of operation of the throttle lever 61.

[0074] Specifically, the throttle lever 61 includes a forward movement throttle lever 61a to move the watercraft body 110 forward, and a reverse movement throttle lever 61b to move the watercraft body 110 backward. The forward movement throttle lever 61a is provided along the right steering operator 60. The reverse movement throttle lever 61b is provided along the left steering operator 60. The lever position sensor 63 includes a forward movement lever position sensor 63a to detect the amount of operation of the forward movement throttle lever 61a, and a reverse movement lever position sensor 63b to detect the amount of operation of the reverse movement throttle lever 61b.

[0075] The trim operator 62 includes a trim-up button and a trim-down button. When the trim-up button is pressed, the nozzle 44 is rotated upward by the trim actuator 55. When the trim-down button is pressed, the nozzle 44 is rotated downward by the trim actuator 55.

[0076] As an example, the controller 8 shown in FIG. 1 includes an engine control unit (ECU), a shift control unit (SCU) to control shifting, a remote control unit (RCU) to control maneuvering in the wireless watercraft maneuvering mode, a steering actuator controller to perform a control to drive the steering actuator 50, etc. Alternatively, the controller may include an integrated control unit. The controller 8 includes a computer that includes a CPU, a ROM, a RAM, etc.

[0077] As described above, the controller 8 performs the oscillation control to repeatedly oscillate the nozzle 44 using the nozzle actuator 5a when the watercraft body 110 is launched from the trailer T. The controller 8 performs the oscillation control based on the oscillation signal I1 received from the remote control 2 via the communicator 1. The oscillation signal I1 is transmitted from the remote control 2 for the pressing duration in which the pressing operation continues.

[0078] Specifically, for a pressing duration in which a pressing operation on the oscillation button 23 of the remote control 2 continues, the controller 8 performs the oscillation control to oscillate the nozzle 44 using the nozzle actuator 5a based on the oscillation signal I1.

[0079] More specifically, for a pressing duration in which a pressing operation on the right-left oscillation button 23a continues, the controller 8 performs the oscillation control to oscillate the nozzle 44 in the right-left direction using the steering actuator 50. Furthermore, for a pressing duration in which a pressing operation on the upward-downward oscillation button 23b continues, the controller 8 oscillates the nozzle 44 in the upward-downward direction using the trim actuator 55 in the oscillation control.

[0080] While the oscillation control is performed (while the oscillation button 23 is pressed) and for a pressing duration in which a pressing operation on the stern float button 24 continues, the controller 8 is able to eject a jet of water in the direction (substantially directly below) that causes the stern 114 to float by directing the jetting port 44a of the nozzle 44 upward using the trim actuator 55 and adjusting the position of the reverse bucket 45 relative to the nozzle 44 to redirect the jet of water downward. Even when the oscillation control is not being performed, the controller 8 is able to eject a jet of water in the direction that causes the stern 114 to float by directing the jetting port 44a of the nozzle 44 upward using the trim actuator 55 and adjusting the position of the reverse bucket 45 relative to the nozzle 44 for the pressing duration in which the pressing operation on the stern float button 24 continues.

[0081] The controller 8 oscillates the nozzle 44 in the right-left direction within the maximum angular range in which the nozzle 44 is movable by the steering actuator 50 in the oscillation control. Furthermore, the controller 8 oscillates the nozzle 44 in the right-left direction with a period of 0.5 seconds or more and 4 seconds or less in the oscillation control, for example. The oscillation period of the nozzle 44 is set to be shorter as the size of the watercraft decreases.

[0082] The controller 8 controls driving of the electric motor 51 to push and pull the nozzle 44 via the nozzle-side steering cable 53 to perform the oscillation control to oscillate the nozzle 44 in the right-left direction. Furthermore, in the oscillation control, the controller 8 pushes and pulls the steering operator 60 via the operator-side steering cable 54 to oscillate the steering operator 60 as well.

[0083] When the watercraft body 110 is launched, the order in which the following actions are performed is determined by an operator of the remote control 2: generation of a reverse thrust by a jet of water from the jet propulsion mechanism 4, oscillation of the nozzle 44 in the right-left direction, oscillation of the nozzle 44 in the upward-downward direction, and floating of the stern 114 by a jet of water from the jet propulsion mechanism 4. These actions may be performed partially simultaneously or individually.

[0084] Normally, when the watercraft body 110 is launched, generation of a reverse thrust by a jet of water from the jet propulsion mechanism 4 is performed first. When launching of the watercraft body 110 is not able to be completed by a reverse thrust alone, one example of a subsequent operation is to oscillate the nozzle 44 in the right-left direction while the reverse thrust is still generated or after the reverse thrust is stopped. When launching of the watercraft body 110 is not able to be completed even by oscillating the nozzle 44 in the right-left direction, oscillation of the nozzle 44 in the upward-downward direction or floating of the stern 114 by a jet of water from the jet propulsion mechanism 4 is then performed. Oscillation of the nozzle 44 in the upward-downward direction and floating of the stern 114 by a jet of water from the jet propulsion mechanism 4 may be performed simultaneously with oscillation of the nozzle 44 in the right-left direction or may be performed after oscillation of the nozzle 44 in the right-left direction is stopped.

[0085] A control process flow for the oscillation control shown in FIG. 14 is now described. The oscillation control is performed by the controller 8. The oscillation control starts from a state in which the launching support mode is selected using the mode switching button 21 at the upper left of the screen of the remote control 2.

[0086] In step S1, it is determined whether or not a + button for the engine rotation speed of the watercraft body operation buttons 22 has been operated. When it is determined that the + button has been operated, the process advances to step S2, and when it is determined that the + button has not been operated, the process advances to step S3.

[0087] In step S2, a jet of water is ejected forward from the jet propulsion mechanism 4, and a reverse thrust of the magnitude set in step S1 is generated. Then, the process advances to step S3.

[0088] In step S3, it is determined whether or not the right-left oscillation button 23a of the remote control 2 has been operated. When it is determined that the right-left oscillation button 23a has been operated, the process advances to step S4, and when it is determined that the right-left oscillation button 23a has not been operated, the process advances to step S5.

[0089] In step S4, the steering actuator 50 is driven to oscillate the nozzle 44 in the right-left direction. The oscillation of the nozzle 44 in the right-left direction in step S4 is continuously performed only while a pressing operation on the right-left oscillation button 23a continues. Then, the process advances to step S5.

[0090] In step S5, it is determined whether or not the upward-downward oscillation button 23b of the remote control 2 has been operated. When it is determined that the upward-downward oscillation button 23b has been operated, the process advances to step S6, and when it is determined that the upward-downward oscillation button 23b has not been operated, the process advances to step S7.

[0091] In step S6, the trim actuator 55 is driven to oscillate the nozzle 44 in the upward-downward direction. Then, the process advances to step S7. The oscillation of the nozzle 44 in the upward-downward direction in step S6 is continuously performed only while a pressing operation on the upward-downward oscillation button 23b continues.

[0092] In step S7, it is determined whether or not the stern float button 24 of the remote control 2 has been operated. When it is determined that the stern float button 24 has been operated, the process advances to step S8, and when it is determined that the stern float button 24 has not been operated, the process advances to step S9.

[0093] In step S8, the orientations of the trim actuator 55 and the reverse bucket 45 are adjusted such that a jet of water is ejected in the direction (substantially directly below) that causes the stern 114 to float. Then, the process advances to step S9. The ejection of the jet of water in the direction that causes the stern 114 to float in step S8 is continuously performed only while a pressing operation on the stern float button 24 continues.

[0094] In step S9, it is determined whether or not the mode switching button 21 has been operated to exit the launching support mode. When it is determined that the launching support mode has been exited, the process advances to END. When it is determined that the launching support mode has not been exited, the process returns to step S1.

[0095] According to the various example embodiments of the present invention described above, the following advantageous effects are achieved.

[0096] According to an example embodiment of the present invention, the jet propulsion system 120 includes the controller 8 configured or programmed to perform the oscillation control to repeatedly oscillate the nozzle 44 using the nozzle actuator 5a when the watercraft body 110 is launched from the trailer T. Accordingly, when the watercraft body 110 is launched, the position of the watercraft body 110 relative to the trailer T is shifted by oscillating the watercraft body 110 such that the watercraft body 110 is released from friction with the trailer T at the same position. Therefore, even when it is difficult or impossible to move the watercraft body 110 in the launching direction by simply ejecting a jet of water forward, the watercraft body 110 is effectively moved in the launching direction by oscillating the nozzle 44. Consequently, the watercraft body 110 is easily launched from the trailer T.

[0097] According to an example embodiment of the present invention, the nozzle actuator 5a includes the steering actuator 50 to rotate the nozzle 44 in the right-left direction to change the orientation of the jet of water in the right-left direction, and the controller 8 is configured or programmed to perform the oscillation control to oscillate the nozzle 44 in the right-left direction using the steering actuator 50. Accordingly, the steering actuator 50 is controlled to easily oscillate the nozzle 44 repeatedly in the right-left direction. Consequently, a launching operation to launch the watercraft body 110 from the trailer T is performed more easily.

[0098] According to an example embodiment of the present invention, the jet propulsion system 120 further includes the remote control 2 to maneuver the watercraft body 110 by remote control, and the communicator 1 on the watercraft body 110 to communicate with the remote control 2, and the controller 8 is configured or programmed to perform the oscillation control based on the oscillation signal I1 received from the remote control 2 via the communicator 1. Accordingly, the remote control 2 enables a person not on board the watercraft body 110 to perform the oscillation control by operating the remote control 2.

[0099] According to an example embodiment of the present invention, the remote control 2 includes the oscillation button 23 to continuously transmit the oscillation signal I1 for the pressing duration in which the pressing operation continues, and the controller 8 is configured or programmed to perform the oscillation control to oscillate the nozzle 44 using the nozzle actuator 5a based on the oscillation signal I1 for the pressing duration. Accordingly, the oscillation button 23 enables the nozzle 44 to be oscillated to oscillate the watercraft body 110 only while an operator of the oscillation button 23 intentionally operates the oscillation button 23.

[0100] According to an example embodiment of the present invention, the remote control 2 is configured to receive an operation to move the watercraft body 110 to the predetermined boarding position after launching of the watercraft body 110 is completed. Accordingly, following the oscillation control to launch the watercraft body 110 by operating the remote control 2, the watercraft body 110 is able to be moved to the predetermined boarding position by operating the remote control 2 that has instructed the oscillation control.

[0101] According to an example embodiment of the present invention, the jet propulsion system 120 further includes the reverse bucket 45 to change the orientation of the jet of water in the forward-rearward direction, and the controller 8 is configured or programmed to generate a backward propulsive force using the reverse bucket 45 while performing the oscillation control. Accordingly, the reverse bucket 45 generates a backward propulsive force simultaneously with oscillating the nozzle 44, and thus the launching operation to launch the watercraft body 110 from the trailer T is performed more easily as compared with a case in which oscillating the nozzle 44 and generating a backward propulsive force using the reverse bucket 45 are performed separately.

[0102] According to an example embodiment of the present invention, the jet propulsion system 120 further includes the reverse bucket 45 to change the orientation of the jet of water in the forward-rearward direction, the nozzle actuator 5a includes the trim actuator 55 to rotate the nozzle 44 in the upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller 8 is configured or programmed to, while performing the oscillation control, eject the jet of water in the direction that causes the stern 114 to float by directing the jetting port 44a of the nozzle 44 upward using the trim actuator 55 and adjusting the position of the reverse bucket 45 relative to the nozzle 44 to redirect the jet of water downward. Accordingly, the jet of water, the orientation of which has been adjusted by the trim actuator 55 and the reverse bucket 45, enables the nozzle 44 to be oscillated while the stern 114 is floated higher in the water. That is, the nozzle 44 is oscillated in a state in which a contact area between the trailer T and the watercraft body 110 is reduced to reduce friction. Consequently, the launching operation to launch the watercraft body 110 from the trailer T is performed more easily.

[0103] According to an example embodiment of the present invention, the controller 8 is configured or programmed to oscillate the nozzle 44 in the right-left direction within the maximum angular range in which the nozzle 44 is movable by the steering actuator 50 in the oscillation control. Accordingly, the nozzle 44 is oscillated in the right-left direction within the maximum angular range such that a large oscillation is imparted to the watercraft body 110, and thus the launching operation to launch the watercraft body 110 from the trailer T is performed even more easily.

[0104] According to an example embodiment of the present invention, the controller 8 is configured or programmed to oscillate the nozzle 44 in the right-left direction with a period of 0.5 seconds or more and 4 seconds or less in the oscillation control. Accordingly, the watercraft body 110 is effectively oscillated by oscillating the nozzle 44 in the right-left direction with a short period of 0.5 seconds or more and 4 seconds or less, for example.

[0105] According to an example embodiment of the present invention, the steering actuator 50 includes the electric motor 51, the transmission gear 52 to transmit the drive force of the electric motor 51 to the nozzle 44, and the nozzle-side steering cable 53 including the first end connected to the transmission gear 52 and the second end connected to the nozzle 44 to push and pull the nozzle 44, and the controller 8 is configured or programmed to control driving of the electric motor 51 to push and pull the nozzle 44 via the nozzle-side steering cable 53 to perform the oscillation control to oscillate the nozzle 44 in the right-left direction. Accordingly, the drive force of the electric motor 51 is transmitted to the nozzle 44 via the transmission gear 52 and the nozzle-side steering cable 53 to easily oscillate the nozzle 44 in the right-left direction.

[0106] According to an example embodiment of the present invention, the steering actuator 50 further includes the operator-side steering cable 54 including the first end connected to the transmission gear 52 and the second end connected to the steering operator 60 to push and pull the steering operator 60, and the controller 8 is configured or programmed to push and pull the steering operator 60 via the operator-side steering cable 54 to oscillate the steering operator 60 as well in the oscillation control. Accordingly, the watercraft body 110 is oscillated by not only the nozzle 44 but also the steering operator 60, and thus a larger oscillation is imparted to the watercraft body 110.

[0107] According to an example embodiment of the present invention, the nozzle actuator 5a includes the trim actuator 55 to rotate the nozzle 44 in the upward-downward direction to change the orientation of the jet of water in the upward-downward direction, and the controller 8 is configured or programmed to oscillate the nozzle 44 in the upward-downward direction using the trim actuator 55 in the oscillation control. Accordingly, the nozzle 44 is easily oscillated repeatedly in the upward-downward direction by the trim actuator 55. Consequently, the launching operation to launch the watercraft body 110 from the trailer T is performed more easily.

[0108] The example embodiments of the present invention described above are illustrative in all points and not restrictive. The extent of the present invention is not defined by the above description of the example embodiments but by the scope of the claims, and all modifications within the meaning and range equivalent to the scope of the claims are further included.

[0109] For example, while the jet propulsion watercraft is preferably a so-called jet ski or jet bike in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the jet propulsion watercraft may alternatively be a so-called jet-propelled sports boat.

[0110] While the jet drive source preferably includes an engine as a drive source to rotate the impeller in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the jet drive source may alternatively include an electric motor as a drive source to rotate the impeller.

[0111] While when the watercraft body is launched, the order in which the following actions are performed is preferably determined by the operator of the remote control: generation of a reverse thrust by a jet of water from the jet propulsion mechanism, oscillation of the nozzle in the right-left direction, oscillation of the nozzle in the upward-downward direction, and floating of the stern by a jet of water from the jet propulsion mechanism in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the order in which the following actions are performed may alternatively be determined in advance: generation of a reverse thrust by a jet of water from the jet propulsion mechanism, oscillation of the nozzle in the right-left direction, oscillation of the nozzle in the upward-downward direction, and floating of the stern by a jet of water from the jet propulsion mechanism, and the controller may alternatively perform the actions in this order. In such a case, switching between the actions may be performed at predetermined time intervals, or the operator of the remote control may operate a predetermined switching button to switch between the actions, for example.

[0112] While the remote control preferably includes the oscillation button in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the watercraft body may alternatively include the oscillation button. That is, the oscillation button may alternatively be provided on the watercraft body.

[0113] While the remote control preferably includes the stern float button in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the watercraft body may alternatively include the stern float button. That is, the stern float button may alternatively be provided on the watercraft body.

[0114] While the nozzle is preferably oscillated in the right-left direction within the maximum angular range in which the nozzle is movable in the oscillation control in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the nozzle may alternatively be oscillated in the right-left direction within an angular range smaller than the maximum angular range described above in the oscillation control.

[0115] While the steering actuator preferably oscillates the steering operator as well when oscillating the nozzle in the right-left direction in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the steering actuator may not oscillate the steering operator when oscillating the nozzle in the right-left direction.

[0116] While the steering actuator is preferably driven by the electric motor in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the steering actuator may alternatively be driven by a cylinder or a solenoid, for example.

[0117] While the process operations performed by the controller are described using a flowchart in a flow-driven manner in which processes are performed in order along a process flow for the convenience of illustration in example embodiments described above, the present invention is not restricted to this. In an example embodiment of the present invention, the process operations performed by the controller may alternatively be performed in an event-driven manner in which the processes are performed on an event basis. In this case, the process operations performed by the controller may be performed in a complete event-driven manner or in a combination of an event-driven manner and a flow-driven manner.

[0118] While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Examples

Embodiment Construction

[0045]Example embodiments of the present invention are hereinafter described with reference to the drawings.

[0046]Jet propulsion watercrafts 100 according to example embodiments of the present invention are now described with reference to FIGS. 1 to 14.

[0047]The jet propulsion watercraft 100 shown in FIGS. 1 and 2 is a personal watercraft, for example, and sails with a relatively small number of people on board. The jet propulsion watercraft 100 is a so-called jet ski or jet bike that glides on the surface of the water. The jet propulsion watercraft 100 includes a watercraft body 110 and a jet propulsion system 120 mounted on the watercraft body 110. The watercraft body 110 includes a hull 111 that defines the bottom of the watercraft, a deck 112 located above the hull 111, and a seat 113 located at the center of the deck 112 in a right-left direction.

[0048]As shown in FIG. 3, the jet propulsion system 120 includes a communicator 1, a remote control 2, a jet drive source 3, a jet pr...

Claims

1. A jet propulsion system comprising:a jet propulsion mechanism located at a stern of a watercraft body and including a nozzle including a jetting port to eject a jet of water to generate a propulsive force;a nozzle actuator to rotate the nozzle to change an orientation of the jet of water; anda controller configured or programmed to perform an oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched.

2. The jet propulsion system according to claim 1, whereinthe nozzle actuator includes a steering actuator to rotate the nozzle in a right-left direction to change the orientation of the jet of water in the right-left direction; andthe controller is configured or programmed to perform the oscillation control to oscillate the nozzle in the right-left direction using the steering actuator.

3. The jet propulsion system according to claim 1, further comprising:a remote control to maneuver the watercraft body by remote control; anda communicator on the watercraft body to communicate with the remote control; whereinthe controller is configured or programmed to perform the oscillation control based on an oscillation signal received from the remote control via the communicator.

4. The jet propulsion system according to claim 3, whereinthe remote control includes an oscillation button to continuously transmit the oscillation signal for a pressing duration in which a pressing operation continues; andthe controller is configured or programmed to perform the oscillation control to oscillate the nozzle using the nozzle actuator based on the oscillation signal for the pressing duration.

5. The jet propulsion system according to claim 3, wherein the remote control is configured to receive an operation to move the watercraft body to a predetermined boarding position after launching of the watercraft body is completed.

6. The jet propulsion system according to claim 1, further comprising:a reverse bucket to change the orientation of the jet of water in a forward-rearward direction; whereinthe controller is configured or programmed to generate a backward propulsive force using the reverse bucket while performing the oscillation control.

7. The jet propulsion system according to claim 1, further comprising:a reverse bucket to change the orientation of the jet of water in a forward-rearward direction; whereinthe nozzle actuator includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction; andthe controller is configured or programmed to, while performing the oscillation control, eject the jet of water in a direction that causes the stern to float by directing the jetting port of the nozzle upward using the trim actuator and adjusting a position of the reverse bucket relative to the nozzle to redirect the jet of water downward.

8. The jet propulsion system according to claim 2, wherein the controller is configured or programmed to oscillate the nozzle in the right-left direction within a maximum angular range in which the nozzle is movable by the steering actuator in the oscillation control.

9. The jet propulsion system according to claim 2, wherein the controller is configured or programmed to oscillate the nozzle in the right-left direction with a period of 0.5 seconds or more and 4 seconds or less in the oscillation control.

10. The jet propulsion system according to claim 2, whereinthe steering actuator includes:an electric motor;a transmission gear to transmit a drive force of the electric motor to the nozzle; anda nozzle-side steering cable including a first end connected to the transmission gear and a second end connected to the nozzle to push and pull the nozzle; andthe controller is configured or programmed to control driving of the electric motor to push and pull the nozzle via the nozzle-side steering cable to perform the oscillation control to oscillate the nozzle in the right-left direction.

11. The jet propulsion system according to claim 10, whereinthe steering actuator further includes an operator-side steering cable including a first end connected to the transmission gear and a second end connected to a steering operator to push and pull the steering operator; andthe controller is configured or programmed to push and pull the steering operator via the operator-side steering cable to also oscillate the steering operator in the oscillation control.

12. The jet propulsion system according to claim 1, whereinthe nozzle actuator includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction; andthe controller is configured or programmed to oscillate the nozzle in the upward-downward direction using the trim actuator in the oscillation control.

13. A jet propulsion watercraft comprising:a watercraft body;a jet propulsion mechanism located at a stern of the watercraft body and including a nozzle including a jetting port to eject a jet of water to generate a propulsive force;a nozzle actuator to rotate the nozzle to change an orientation of the jet of water from the jetting port; anda controller configured or programmed to perform an oscillation control to repeatedly oscillate the nozzle using the nozzle actuator when the watercraft body is launched.

14. The jet propulsion watercraft according to claim 13, whereinthe nozzle actuator includes a steering actuator to rotate the nozzle in a right-left direction to change the orientation of the jet of water in the right-left direction; andthe controller is configured or programmed to perform the oscillation control to oscillate the nozzle in the right-left direction using the steering actuator.

15. The jet propulsion watercraft according to claim 13, further comprising:a communicator to communicate with a remote control configured or programmed to maneuver the watercraft body by remote control; whereinthe controller is configured or programmed to perform the oscillation control based on an oscillation signal received from the remote control via the communicator.

16. The jet propulsion watercraft according to claim 15, whereinthe remote control includes an oscillation button to continuously transmit the oscillation signal for a pressing duration in which a pressing operation continues; andthe controller is configured or programmed to perform the oscillation control to oscillate the nozzle using the nozzle actuator based on the oscillation signal for the pressing duration.

17. The jet propulsion watercraft according to claim 15, wherein the remote control is configured to receive an operation to move the watercraft body to a predetermined boarding position after launching of the watercraft body is completed.

18. The jet propulsion watercraft according to claim 13, further comprising:a reverse bucket to change the orientation of the jet of water in a forward-rearward direction; whereinthe controller is configured or programmed to generate a backward propulsive force using the reverse bucket while performing the oscillation control.

19. The jet propulsion watercraft according to claim 13, further comprising:a reverse bucket to change the orientation of the jet of water in a forward-rearward direction; whereinthe nozzle actuator includes a trim actuator to rotate the nozzle in an upward-downward direction to change the orientation of the jet of water in the upward-downward direction; andthe controller is configured or programmed to, while performing the oscillation control, eject the jet of water in a direction that causes the stern to float by directing the jetting port of the nozzle upward using the trim actuator and adjusting a position of the reverse bucket relative to the nozzle to redirect the jet of water downward.

20. A watercraft body launching method comprising:generating a backward propulsive force using a jet of water from a jetting port of a nozzle of a jet propulsion mechanism when a watercraft body is launched from a trailer; andrepeatedly oscillating the nozzle when the watercraft body is launched from the trailer.

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