Ship, ship control device, ship control method and program

Abstract

This ship, provided with an engine, a jet propulsion device, a ship controller and a ship position detection unit, the jet propulsion device is provided with a nozzle that emits a jet stream generated by the drive force outputted from the engine, and a bucket that changes the direction of the jet stream. The bucket positions include at least a forward position in which the jet propulsion device generates propulsion force for propelling the ship forward, a neutral position in which the jet propulsion device does not generate propulsion force for moving the ship, and a forward-side intermediate position between the forward position and the neutral position. The ship controller has a vessel fixed point hold mode which executes feedback control of the engine and the jet propulsion device on the basis of the deviation between pre-set target ship position and an actual ship position, and during the vessel fixed point hold mode, controls both the bucket positions, which includes the forward-side intermediate position, and controls the engine rotation speed.

Description

[Technical Field]

[0001] The present invention relates to a ship, a ship control device, a ship control method, and a program. This application claims priority based on Japanese Patent Application No. 2021-106920, filed on June 28, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] Small boats with jet propulsion devices have been known for some time (see, for example, Patent Document 1). In the small boat described in Patent Document 1, the bucket is configured to be switchable between a raised position (forward position) and a lowered position (reverse position). When the bucket is in the raised position, the water jetting out of the nozzle heads toward the rear of the hull without hitting the bucket, causing the small boat to move forward. When the bucket is in the lowered position, the water jetting out of the nozzle hits the bucket and heads toward the front of the hull, causing the small boat to move backward. However, Patent Document 1 does not describe control of ship's fixed position keeping. Therefore, the technology described in Patent Document 1 cannot appropriately control ship's fixed position keeping.

[0003] Furthermore, jet propulsion boats that move forward by ejecting a jet of water backward from a jet propulsion mechanism are known (see, for example, Patent Document 2). The jet propulsion boat described in Patent Document 2 is equipped with a bucket that changes the direction of the jet of water from the jet propulsion mechanism. The bucket is movable between a forward position and an operating position, and the forward position is a position where the bucket is retracted from the jet outlet. The operating position is a position where the bucket faces the jet outlet. In the jet propulsion boat described in Patent Document 2, the bucket is positioned in a first operating position (reverse position) to cause the jet propulsion boat to move backward. Patent Document 2 describes that the jet propulsion boat is held in a fixed position by disposing the bucket in the second operating position (neutral position). However, in an environment where there are external disturbances (such as wind and currents), such as at sea, as described in Patent Document 2, it is not possible to hold a jet propulsion boat in a fixed position (fixed point holding) simply by placing the bucket in a neutral position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-237693 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-073790 Summary of the Invention [Problem to be solved by the invention]

[0005] Through extensive research, the inventors have discovered that by controlling the bucket to be positioned at an intermediate position between the forward position and the neutral position, or at an intermediate position between the reverse position and the neutral position, and by controlling the rotational speed of the engine that outputs the driving force that generates the jet stream, it is possible to control the vessel to maintain a fixed position with high precision even in an environment where external disturbances are present. In other words, an object of the present invention is to provide a ship, a ship control device, a ship control method, and a program that can improve the controllability of ship fixed position keeping. [Means for solving the problem]

[0006] One aspect of the present invention is a vessel comprising: an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; a vessel control device that controls the engine and the jet propulsion device; and a vessel position detection unit that detects an actual vessel position, which is the actual position of the vessel. The jet propulsion device comprises a nozzle that emits a jet jet generated by the driving force output from the engine; and a bucket that changes the direction of the jet jet emitted from the nozzle. The positions of the bucket include at least a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, a neutral position where the jet propulsion device does not generate a propulsive force that moves the vessel, and a forward intermediate position between the forward position and the neutral position. The vessel control device has a vessel fixed position holding mode that executes feedback control of the engine and the jet propulsion device based on the deviation between a target vessel position that is a predetermined target position of the vessel and the actual vessel position. In the vessel fixed position holding mode, both control of the position of the bucket, including the forward intermediate position, and control of the rotational speed of the engine are executed.

[0007] One aspect of the present invention is a vessel including an engine that outputs a driving force, a jet propulsion device that generates a propulsive force for the vessel by the driving force output from the engine, a vessel control device that controls the engine and the jet propulsion device, and a vessel position detection unit that detects an actual vessel position, which is the actual position of the vessel, wherein the jet propulsion device includes a nozzle that emits a jet jet generated by the driving force output from the engine, and a bucket that changes the direction of the jet jet emitted from the nozzle, and the position of the bucket has a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, and a forward position where the bucket changes the direction of the propulsive force that moves the vessel forward. The vessel includes at least a neutral position in which the jet propulsion device does not generate a propulsive force to move the vessel, a reverse position in which the jet propulsion device generates a propulsive force to move the vessel astern, and an intermediate position on the reverse side between the reverse position and the neutral position, and the vessel control device has a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on the deviation between a target vessel position, which is a predetermined target position of the vessel, and an actual vessel position, and in the vessel fixed position holding mode, both control of the position of the bucket, including the intermediate position on the astern side, and control of the rotational speed of the engine are performed.

[0008] One aspect of the present invention is a vessel including an engine that outputs a driving force, a jet propulsion device that generates a propulsive force for the vessel by the driving force output from the engine, a vessel control device that controls the engine and the jet propulsion device, and a vessel position detection unit that detects an actual vessel position, which is the actual position of the vessel, wherein the jet propulsion device includes a nozzle that emits a jet jet generated by the driving force output from the engine, and a bucket that changes the direction of the jet jet emitted from the nozzle, and the position of the bucket is set to a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, and a forward position where the jet propulsion device generates a propulsive force that moves the vessel. The vessel includes at least a neutral position where no propulsion device generates any thrust, a reverse position where the jet propulsion device generates thrust to move the vessel in reverse, a forward intermediate position between the forward position and the neutral position, and a reverse intermediate position between the reverse position and the neutral position, and the vessel control device has a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on the deviation between a target vessel position, which is a predetermined target position of the vessel, and an actual vessel position, and in the vessel fixed position holding mode, both control of the position of the bucket, including the forward intermediate position and the reverse intermediate position, and control of the rotational speed of the engine are performed.

[0009] One aspect of the present invention is a vessel control device provided on a vessel including an engine that outputs driving force, a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine, and a vessel position detection unit that detects an actual vessel position, which is the actual position of the vessel. The jet propulsion device includes a nozzle that emits a jet jet generated by the driving force output from the engine, and a bucket that changes the direction of the jet jet emitted from the nozzle. The positions of the bucket include at least a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, a neutral position where the jet propulsion device does not generate a propulsive force that moves the vessel, and a forward intermediate position between the forward position and the neutral position. The vessel control device has a vessel fixed position holding mode that performs feedback control of the engine and the jet propulsion device based on the deviation between a target vessel position, which is a predetermined target position of the vessel, and the actual vessel position. During the vessel fixed position holding mode, the vessel control device controls both the position of the bucket, including the forward intermediate position, and the rotational speed of the engine.

[0010] One aspect of the present invention is a vessel control device provided on a vessel including an engine that outputs driving force, a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine, and a vessel position detection unit that detects an actual vessel position, which is the actual position of the vessel. The jet propulsion device includes a nozzle that emits a jet jet generated by the driving force output from the engine, and a bucket that changes the direction of the jet jet emitted from the nozzle. The positions of the bucket include at least a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, a neutral position where the jet propulsion device does not generate a propulsive force that moves the vessel, a reverse position where the jet propulsion device generates a propulsive force that moves the vessel reverse, and a reverse intermediate position between the reverse position and the neutral position. The vessel control device has a vessel fixed position holding mode that executes feedback control of the engine and the jet propulsion device based on the deviation between a target vessel position, which is a predetermined target position of the vessel, and the actual vessel position. In the vessel fixed position holding mode, the vessel control device executes both control of the position of the bucket, including the reverse intermediate position, and control of the rotational speed of the engine.

[0011] One aspect of the present invention is a vessel control device provided on a vessel including an engine that outputs driving force, a jet propulsion device that generates a propulsive force for the vessel by the driving force output from the engine, and a vessel position detection unit that detects an actual vessel position, which is the actual position of the vessel, wherein the jet propulsion device includes a nozzle that emits a jet jet generated by the driving force output from the engine, and a bucket that changes the direction of the jet jet emitted from the nozzle, and the position of the bucket is set to a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, and a forward position where the jet propulsion device does not generate a propulsive force that moves the vessel. The vessel control device includes at least a neutral position, a reverse position where the jet propulsion device generates a propulsive force that moves the vessel astern, a forward intermediate position between the forward position and the neutral position, and a reverse intermediate position between the reverse position and the neutral position, and the vessel control device has a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on the deviation between a target vessel position, which is a predetermined target position of the vessel, and an actual vessel position, and in the vessel fixed position holding mode, controls both the position of the bucket, including the forward intermediate position and the reverse intermediate position, and controls the rotational speed of the engine.

[0012] One aspect of the present invention is a ship control method for controlling a ship which includes an engine that outputs driving force, a jet propulsion device that generates a propulsive force for the ship using the driving force output from the engine, and a ship position detection unit that detects an actual ship position, which is the actual position of the ship. The jet propulsion device includes a nozzle that emits a jet jet generated by the driving force output from the engine, and a bucket that changes the direction of the jet jet emitted from the nozzle. The positions of the bucket include at least a forward position where the jet propulsion device generates a propulsive force that moves the ship forward, a neutral position where the jet propulsion device does not generate a propulsive force that moves the ship, and a forward intermediate position between the forward position and the neutral position. The ship control method also includes a ship fixed position holding step that executes feedback control of the engine and the jet propulsion device based on the deviation between a target ship position, which is a predetermined target position of the ship, and the actual ship position. When the ship fixed position holding step is executed, both control of the position of the bucket, including the forward intermediate position, and control of the rotational speed of the engine are executed.

[0013] One aspect of the present invention is a ship control method for controlling a ship which includes an engine that outputs driving force, a jet propulsion device that generates a propulsive force for the ship using the driving force output from the engine, and a ship position detection unit that detects an actual ship position, which is the actual position of the ship. The jet propulsion device includes a nozzle that emits a jet jet generated by the driving force output from the engine, and a bucket that changes the direction of the jet jet emitted from the nozzle. The positions of the bucket include at least a forward position where the jet propulsion device generates a propulsive force that moves the ship forward, a neutral position where the jet propulsion device does not generate a propulsive force that moves the ship backward, a reverse position where the jet propulsion device generates a propulsive force that moves the ship backward, and a reverse intermediate position between the reverse position and the neutral position. The ship control method also includes a ship fixed position holding step that executes feedback control of the engine and the jet propulsion device based on the deviation between a target ship position, which is a predetermined target position of the ship, and the actual ship position. When the ship fixed position holding step is executed, both control of the position of the bucket, including the reverse intermediate position, and control of the rotational speed of the engine are executed.

[0014] One aspect of the present invention is a vessel control method for controlling a vessel having an engine that outputs a driving force, a jet propulsion device that generates a propulsive force for the vessel by the driving force output from the engine, and a vessel position detection unit that detects an actual vessel position, which is the actual position of the vessel, wherein the jet propulsion device has a nozzle that emits a jet jet generated by the driving force output from the engine, and a bucket that changes the direction of the jet jet emitted from the nozzle, and the position of the bucket is set to a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, and a forward position where the jet propulsion device does not generate a propulsive force that moves the vessel. The vessel control method includes at least a neutral position, a reverse position where the jet propulsion device generates a propulsive force that moves the vessel in reverse, a forward intermediate position between the forward position and the neutral position, and a reverse intermediate position between the reverse position and the neutral position, and includes a vessel fixed position holding step that executes feedback control of the engine and the jet propulsion device based on the deviation between a target vessel position, which is a predetermined target position of the vessel, and an actual vessel position, and when the vessel fixed position holding step is executed, both control of the position of the bucket, including the forward intermediate position and the reverse intermediate position, and control of the rotational speed of the engine are executed.

[0015] One aspect of the present invention is a program for causing a computer mounted on a vessel, the computer including an engine that outputs driving force, a jet propulsion device that generates propulsion force for the vessel using the driving force output from the engine, and a vessel position detection unit that detects the actual vessel position, to execute a vessel fixed position holding step that performs feedback control of the engine and the jet propulsion device based on the deviation between a target vessel position that is a predetermined target position for the vessel and the actual vessel position, the jet propulsion device including a nozzle that emits a jet jet generated by the driving force output from the engine and a bucket that changes the direction of the jet jet emitted from the nozzle, the positions of the bucket including a forward position where the jet propulsion device generates a propulsion force that moves the vessel forward, a neutral position where the jet propulsion device does not generate a propulsion force that moves the vessel, and a forward intermediate position between the forward position and the neutral position, and when the vessel fixed position holding step is executed, both control of the position of the bucket including the forward intermediate position and control of the rotational speed of the engine are executed.

[0016] One aspect of the present invention is a program for causing a computer mounted on a vessel, the computer including an engine that outputs driving force, a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine, and a vessel position detection unit that detects the actual vessel position, to execute a vessel fixed position holding step that performs feedback control of the engine and the jet propulsion device based on the deviation between a target vessel position that is a predetermined target position for the vessel and the actual vessel position, the jet propulsion device including a nozzle that emits a jet jet generated by the driving force output from the engine and a bucket that changes the direction of the jet jet emitted from the nozzle, the positions of the bucket including a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, a neutral position where the jet propulsion device does not generate a propulsive force that moves the vessel, a reverse position where the jet propulsion device generates a propulsive force that moves the vessel reverse, and a reverse intermediate position between the reverse position and the neutral position, and when the vessel fixed position holding step is executed, both control of the position of the bucket including the reverse intermediate position and control of the rotational speed of the engine are executed.

[0017] One aspect of the present invention is a program for causing a computer mounted on a vessel to execute a vessel fixed position holding step that executes feedback control of the engine and the jet propulsion device based on a deviation between a target vessel position that is a preset target position of the vessel and the actual vessel position, the program being configured to cause the computer mounted on the vessel to include an engine that outputs driving force, a jet propulsion device that generates a propulsive force for the vessel by the driving force output from the engine, and a vessel position detection unit that detects an actual vessel position that is the actual position of the vessel, the program including the jet propulsion device including a nozzle that emits a jet jet generated by the driving force output from the engine, and a jet propulsion device that generates a propulsive force for the vessel by the driving force output from the engine, the jet propulsion device being configured to generate ... propulsion device being configured to generate a propulsive force for the vessel by the driving force output from the engine, the propulsion device being configured to generate a propulsive force for the vessel by the driving force output from the engine, the propulsion device being configured to generate a propulsive force for the vessel by the driving force output from the engine, the propulsion device being configured to generate a propulsive force for the vessel by the driving force output from the engine, the propulsion device being configured to generate a propulsive force for the vessel by the driving force output from the engine, the propulsion device being configured to generate a propulsive force for the vessel by the driving force output from the engine, the propulsion device being configured and a bucket that changes the direction of the jet flow, wherein the positions of the bucket include at least a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward, a neutral position where the jet propulsion device does not generate a propulsive force that moves the vessel backward, a forward intermediate position between the forward position and the neutral position, and a reverse intermediate position between the reverse position and the neutral position, and when the vessel fixed position holding step is executed, both control of the position of the bucket, including the forward intermediate position and the reverse intermediate position, and control of the rotational speed of the engine are executed. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a ship, a ship control device, a ship control method, and a program that can improve the controllability of ship fixed position keeping. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram illustrating an example of a ship according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a configuration of a nozzle and a bucket. [Figure 3] FIG. 10 is a diagram showing an example of a bucket position controlled by a bucket position control unit of the vessel control device when the vessel control device is in a vessel fixed position holding mode. [Figure 4]5 is a flowchart illustrating an example of processing executed by the vessel control device of the vessel according to the first embodiment. [Figure 5] FIG. 10 is a diagram for explaining the position of the bucket controlled by the bucket position control unit of the vessel control device when the vessel control device of the vessel is in a vessel fixed position holding mode according to the second embodiment. [Figure 6] FIG. 11 is a diagram showing an example of a bucket position controlled by a bucket position control unit of the vessel control device when the vessel control device of the vessel is in a vessel fixed position holding mode according to the third embodiment. [Figure 7] 10 is a flowchart illustrating an example of processing executed by a vessel control device of a vessel according to a third embodiment. [Figure 8] 10 is a diagram for explaining the position of the bucket controlled by a bucket position control unit of the vessel control device when the vessel control device of the vessel is in a vessel fixed position holding mode according to the fourth embodiment. FIG. [Figure 9] 10 is a flowchart illustrating an example of processing executed by a ship control device of a ship according to a fifth embodiment. [Figure 10] FIG. 3 is a diagram showing an example of control that can be performed in the ships according to the first to seventh embodiments. [Figure 11] FIG. 3 is a diagram showing an example of control that can be performed in the ships according to the first to seventh embodiments. [Figure 12] FIG. 3 is a diagram showing an example of control that can be performed in the ships according to the first to seventh embodiments. [Figure 13] FIG. 10 is a diagram showing another example of control that can be performed in the marine vessels according to the first to seventh embodiments. [Figure 14] FIG. 10 is a diagram showing another example of control that can be performed in the marine vessels according to the first to seventh embodiments. [Figure 15] FIG. 10 is a diagram showing another example of control that can be performed in the marine vessels according to the first to seventh embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0020] First Embodiment A first embodiment of a ship, a ship control device, a ship control method, and a program according to the present invention will be described below.

[0021] FIG. 1 is a diagram showing an example of a ship 1 according to a first embodiment. In the example shown in Fig. 1, the boat 1 of the first embodiment is a personal watercraft (PWC) having basic functions similar to those of a PWC (personal watercraft) shown in Fig. 1 of Patent Document 1 or Patent Document 2. The boat 1 includes, for example, an engine 11, a jet propulsion unit 12, a boat control device 13, a boat position detection unit 14, and an operation unit 15. The engine 11 outputs a driving force. The jet propulsion device 12 generates a propulsive force for the boat 1 by using the driving force output from the engine 11. The jet propulsion device 12 includes a nozzle 12A and a bucket 12B. The nozzle 12A ejects a jet stream generated by the driving force output from the engine 11. The bucket 12B changes the direction of the jet stream ejected from the nozzle 12A.

[0022] Fig. 2 is a diagram showing an example of the configuration of the nozzle 12A and the bucket 12B. More specifically, Fig. 2 is a diagram for explaining an example of the basic position of the bucket 12B. Specifically, Fig. 2(A) shows the positional relationship between the nozzle 12A and the bucket 12B and the jet flow when the bucket 12B is positioned at the forward position F. Fig. 2(B) shows the positional relationship between the nozzle 12A and the bucket 12B and the jet flow when the bucket 12B is positioned at the neutral position N. Fig. 2(C) shows the positional relationship between the nozzle 12A and the bucket 12B and the jet flow when the bucket 12B is positioned at the reverse position R.

[0023] As shown in Fig. 2(A), when bucket 12B is positioned at forward position F, the jet stream emitted from nozzle 12A does not hit bucket 12B. In other words, the direction of the jet stream emitted from nozzle 12A is not changed by bucket 12B. As a result, when bucket 12B is positioned at forward position F, jet propulsion device 12 generates a propulsive force that moves boat 1 forward (in other words, a propulsive force that moves boat 1 to the right in Fig. 2(A)). As shown in Fig. 2(B), when bucket 12B is positioned at neutral position N, a portion of the jet stream emitted from nozzle 12A hits bucket 12B, and the remaining portion of the jet stream emitted from nozzle 12A does not hit bucket 12B. Therefore, when bucket 12B is positioned at neutral position N, the jet stream emitted from nozzle 12A is represented by an arrow in Fig. 2(B). As a result, when bucket 12B is positioned at neutral position N, jet propulsion device 12 does not generate a propulsive force that moves boat 1. As shown in Fig. 2(C), when bucket 12B is positioned at reverse position R, all of the jet stream emitted from nozzle 12A hits bucket 12B. In other words, the direction of the jet stream emitted from nozzle 12A is changed by bucket 12B to the right in Fig. 2(C). As a result, when bucket 12B is positioned at reverse position R, jet propulsion device 12 generates a propulsive force that moves boat 1 backward (in other words, a propulsive force that moves boat 1 leftward in Fig. 2(C)).

[0024] In the example shown in Fig. 2, bucket 12B is configured to be rotatable about a central axis of rotation extending in the horizontal direction (from the front to the back in Fig. 2), but in other examples, bucket 12B may be configured to be rotatable about a central axis of rotation extending in the vertical direction (the up-and-down direction in Fig. 2). In more detail, as described in Japanese Patent No. 3971161, for example, bucket 12B may be configured to be made up of two members, and the two members may be configured to open left and right.

[0025] 1, the vessel control device 13 controls the engine 11 and the jet propulsion device 12. The vessel control device 13 includes, for example, a bucket position control unit 13A and an engine rotation speed control unit 13B. The bucket position control unit 13A controls the position of the bucket 12B (for example, control to place the bucket 12B in a forward position F, control to place the bucket 12B in a neutral position N, control to place the bucket 12B in a reverse position R, etc.). The engine rotation speed control section 13B controls the rotation speed of the engine 11 (that is, controls to change the strength of the jet flow shown in FIG. 2). The vessel position detection unit 14 detects the actual vessel position, which is the actual position of the vessel 1. The vessel position detection unit 14 includes, for example, a GPS (Global Positioning System) device. The GPS device calculates the position coordinates of the vessel 1 by receiving signals from multiple GPS satellites. The operation unit 15 accepts input operations from the boat operator. The operation unit 15 includes a throttle operation unit 15A and a shift operation unit 15B. The throttle operation unit 15A is configured similarly to the throttle operation unit described in Patent Document 2, for example, and accepts input operations from the boat operator to adjust the rotation speed of the engine 11. The shift operation unit 15B is configured similarly to the shift operation unit described in Patent Document 2, for example, and accepts input operations from the boat operator to switch the position of the bucket 12B between a forward position F, a neutral position N, and a reverse position R. In the normal mode of the vessel control device 13, the bucket position control unit 13A controls the position of the bucket 12B to one of the forward position F, neutral position N, and reverse position R, based on the input operation of the vessel operator received by the shift operation unit 15B. Also, in the normal mode of the vessel control device 13, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 (control to change the strength of the jet flow shown in FIG. 2) based on the input operation of the vessel operator received by the throttle operation unit 15A.

[0026] 1, the vessel control device 13 has not only the normal mode described above but also a vessel fixed position mode. In the vessel fixed position mode of the vessel control device 13, the vessel control device 13 performs feedback control (e.g., PID control) of the engine 11 and the jet propulsion device 12 based on the deviation between a target vessel position, which is a preset target position of the vessel 1, and the actual vessel position. The target vessel position is set in advance, for example, in response to an input operation by the vessel operator (for example, an input operation in which the vessel operator turns on a switch (not shown) when the vessel 1 is positioned at a desired position). In another example, the target vessel position may be set in advance by, for example, the operator inputting numerical coordinates of a desired position of the vessel 1.

[0027] FIG. 3 is a diagram showing an example of the position of the bucket 12B controlled by the bucket position control unit 13A of the ship control device 13 when the ship control device 13 is in the ship fixed position holding mode. In the example shown in Figure 3, when the ship control device 13 is in ship fixed position holding mode, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A of the ship control device 13 are set to a neutral position N, a forward position F, and three forward side intermediate positions N+1, N+2, and N+3 located therebetween. In other words, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A when the ship control device 13 is in ship fixed position holding mode include the neutral position N, the forward side intermediate position N+1, the forward side intermediate position N+2, the forward side intermediate position N+3, and the forward position F. In the example shown in FIG. 3, three forward intermediate positions N+1, N+2, and N+3 are set as forward intermediate positions between the neutral position N and the forward position F, but in other examples, any number of forward intermediate positions other than three may be set as forward intermediate positions between the neutral position N and the forward position F.

[0028] 3, the rotation angle θ of bucket 12B required to move bucket 12B from neutral position N to forward position F is divided into four. Furthermore, the position where bucket 12B is rotated by (θ / 4) from neutral position N is set as forward-side intermediate position N+1, the position where bucket 12B is rotated by (2θ / 4) from neutral position N is set as forward-side intermediate position N+2, and the position where bucket 12B is rotated by (3θ / 4) from neutral position N is set as forward-side intermediate position N+3. In the example shown in FIG. 3 , forward movement side intermediate positions N+1, N+2, and N+3 are set at positions obtained by dividing the rotation angle θ of bucket 12B, which is necessary to move bucket 12B from neutral position N to forward movement position F, at equal angular intervals. However, in other examples, the rotation angle of bucket 12B necessary to move bucket 12B from neutral position N to forward movement side intermediate position N+1, the rotation angle of bucket 12B necessary to move bucket 12B from forward movement side intermediate position N+1 to forward movement side intermediate position N+2, the rotation angle of bucket 12B necessary to move bucket 12B from forward movement side intermediate position N+2 to forward movement side intermediate position N+3, and the rotation angle of bucket 12B necessary to move bucket 12B from forward movement side intermediate position N+3 to forward movement position F may be different from one another.

[0029] In the example shown in Figure 3, when the ship control device 13 is in a ship fixed position holding mode, the ship control device 13 controls both the position of the bucket 12B (control to place the bucket 12B at any of the neutral position N, forward side intermediate positions N+1, N+2, N+3, and forward position F) and the rotational speed of the engine 11. In detail, when the vessel control device 13 is in vessel fixed position holding mode, the vessel control device 13 sets the rotational speed of the engine 11 to a predetermined value so that the vessel 1 is held at a fixed position at the target vessel position, and executes control to set the position of the bucket 12B to one of the forward position F, neutral position N, and three forward side intermediate positions N+1, N+2, and N+3.

[0030] [Table 1]

[0031] Table 1 shows an example of the correspondence between the rotation speed of the engine 11, the position of the bucket 12B, etc. when the ship control device 13 is in the ship fixed position holding mode. In the example shown in Table 1, when the deviation between the target vessel position and the actual vessel position in the vessel control device 13's fixed vessel positioning mode is zero, the control amount (feedback control amount) calculated by the vessel control device 13 becomes zero. As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the neutral position N. Specifically, the bucket position control unit 13A controls the position of the bucket 12B to the neutral position N even if the shift operation unit 15B does not accept an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE" (the rotation speed of the engine 11 in an idling state). Specifically, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. Therefore, the jet propulsion device 12 does not generate a propulsive force to move the vessel 1, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 1, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+1" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+1"), the control amount calculated by the vessel control device 13 becomes "+1". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward intermediate position N+1. In detail, the bucket position control unit 13A controls the position of the bucket 12B to the forward intermediate position N+1 even if the shift operation unit 15B does not receive an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not receive an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force that moves the vessel 1 forward to change the deviation from "+1" to zero, and the vessel 1 is maintained at the target vessel position.

[0032] In the example shown in Table 1, when the deviation between the target vessel position and the actual vessel position in the vessel stationary position mode of the vessel control device 13 is "+2" (> deviation "+1") (in other words, when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+2"), the control amount calculated by the vessel control device 13 is "+2" (> control amount "+1"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward intermediate position N+2. In more detail, the bucket position control unit 13A controls the position of the bucket 12B to the forward intermediate position N+2 even if the shift operation unit 15B does not receive an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE." In more detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not receive an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to change the deviation from "+2" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 1, when the deviation between the target vessel position and the actual vessel position in the vessel stationary position mode of the vessel control device 13 is "+3" (> deviation "+2") (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+3"), the control amount calculated by the vessel control device 13 is "+3" (> control amount "+2"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward intermediate position N+3. In detail, the bucket position control unit 13A controls the position of the bucket 12B to the forward intermediate position N+3 even if the shift operation unit 15B does not receive an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not receive an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+3" to zero, and the vessel 1 is maintained at the target vessel position.

[0033] In the example shown in Table 1, when the deviation between the target vessel position and the actual vessel position in the vessel stationary position mode of the vessel control device 13 is "+4" (> deviation "+3") (in other words, when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+4"), the control amount calculated by the vessel control device 13 is "+4" (> control amount "+3"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward position F. In more detail, the bucket position control unit 13A controls the position of the bucket 12B to the forward position F even if the shift operation unit 15B does not receive an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". In more detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not receive an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+4" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 1, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+5" (> deviation "+4") (in other words, when the actual vessel position is shifted aft of the target vessel position of the vessel 1 by an amount equivalent to the deviation "+5"), the control amount calculated by the vessel control device 13 becomes "+5" (> control amount "+4"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward position F. In detail, the bucket position control unit 13A controls the position of the bucket 12B to the forward position F even if the shift operation unit 15B does not accept an input operation from the vessel operator. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+1" (> rotation speed "IDLE" of the engine 11). In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE+1" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. As a result, the jet propulsion unit 12 generates a propulsive force that moves the vessel 1 forward to reduce the deviation from "+5" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 1, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+6" (> deviation "+5") (in other words, when the actual vessel position is shifted aft of the target vessel position of the vessel 1 by an amount equivalent to the deviation "+6"), the control amount calculated by the vessel control device 13 becomes "+6" (> control amount "+5"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward position F. In detail, the bucket position control unit 13A controls the position of the bucket 12B to the forward position F even if the shift operation unit 15B does not accept an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+2" (> rotation speed of the engine 11 "IDLE+1"). In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE+2" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. As a result, the jet propulsion unit 12 generates a thrust force that moves the vessel 1 forward to reduce the deviation from "+6" to zero, and the vessel 1 is maintained at the target vessel position.

[0034] In the example shown in Table 1, when the vessel control device 13 is in vessel fixed position holding mode, if the position of the bucket 12B is set to the neutral position N, the actual vessel position will be located further aft than the target vessel position, and if the position of the bucket 12B is set to the forward position F, the actual vessel position will be located further forward than the target vessel position (i.e., if a relatively small rearward external force is applied to the vessel 1), the position of the bucket 12B will be set to, for example, the forward side intermediate position N+1, the forward side intermediate position N+2, the forward side intermediate position N+3, etc., and the rotational speed of the engine 11 will be set to "IDLE" so that the vessel 1 is held in a fixed position at the target vessel position.

[0035] In other words, in the example shown in Table 1, the position of the bucket 12B is set to forward intermediate positions N+1, N+2, and N+3, and when the ship control device 13 is in ship fixed position holding mode, both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are executed, so that, for example, when the deviation between the target ship position and the actual ship position is "+1," "+2," or "+3," the bucket 12B is positioned at forward position F, which prevents the ship 1 from moving too far forward of the target ship position. In other words, in the ship 1 of the first embodiment, the controllability of ship fixed positioning can be improved compared to when the forward intermediate positions N+1, N+2, and N+3 are not set as the position of the bucket 12B, or when both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are not executed when the ship control device 13 is in ship fixed positioning mode.

[0036] In the example shown in Table 1, the rotational speed of the engine 11 is controlled to "IDLE" when the position of the bucket 12B is set to forward-side intermediate positions N+1, N+2, and N+3, but in other examples, the rotational speed of the engine 11 may be controlled to a rotational speed other than "IDLE" (for example, "IDLE+1," "IDLE+2," etc.) when the position of the bucket 12B is set to forward-side intermediate positions N+1, N+2, and N+3. Specifically, when the position of the bucket 12B changes from forward-side intermediate position N+1 to forward-side intermediate position N+2 to forward-side intermediate position N+3, the rotational speed of the engine 11 may be changed, for example, from "IDLE" to "IDLE+1" to "IDLE+2."

[0037] FIG. 4 is a flowchart illustrating an example of processing executed by the vessel control device 13 of the vessel 1 according to the first embodiment. 4, in step S10, the ship control device 13 determines whether it is in ship fixed position mode (determines whether it is in ship fixed position mode or normal mode). If the ship control device 13 is in ship fixed position mode, the process proceeds to step S11, and if the ship control device 13 is in normal mode, the process proceeds to step S12. In step S11, the vessel control device 13 executes feedback control of the engine 11 and the jet propulsion device 12 based on the deviation between the target vessel position and the actual vessel position. In detail, the vessel control device 13 executes control to keep the vessel 1 at the target vessel position (holds the vessel 1 at a fixed position). Specifically, in step S11A, the bucket position control unit 13A of the vessel control device 13 controls the position of the bucket 12B. In the example shown in Fig. 3 described above, the positions of the bucket 12B include the neutral position N, the forward position F, and forward-side intermediate positions N+1, N+2, and N+3. In addition, in step S11B, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11. That is, when step S11 is executed, both the control of the position of the bucket 12B including the forward intermediate positions N+1, N+2, and N+3 and the control of the rotation speed of the engine 11 are executed. In step S12, the vessel control device 13 executes control in the normal mode. Specifically, the bucket position control unit 13A controls the position of the bucket 12B to one of the forward position F, the neutral position N, and the reverse position R, based on the input operation of the vessel operator received by the shift operation unit 15B. In addition, the engine rotation speed control unit 13B controls the rotation speed of the engine 11, based on the input operation of the vessel operator received by the throttle operation unit 15A.

[0038] Second Embodiment A second embodiment of the ship, ship control device, ship control method, and program according to the present invention will now be described. The vessel 1 of the second embodiment is configured similarly to the vessel 1 of the first embodiment described above, except for the points described below. Therefore, the vessel 1 of the second embodiment can achieve the same effects as the vessel 1 of the first embodiment described above, except for the points described below.

[0039] 1, the boat 1 of the second embodiment includes, for example, an engine 11, a jet propulsion device 12, a boat control device 13, a boat position detection unit 14, and an operation unit 15. The bucket 12B of the jet propulsion device 12 of the boat 1 of the second embodiment is configured to be positionable in a forward position F, a neutral position N, and a reverse position R. The bucket position control unit 13A of the ship control device 13 of the ship 1 of the second embodiment controls the position of the bucket 12B (for example, control to position the bucket 12B at a forward position F, control to position the bucket 12B at a neutral position N, control to position the bucket 12B at a reverse position R, etc.). The engine rotation speed control unit 13B of the vessel control device 13 of the vessel 1 of the second embodiment controls the rotation speed of the engine 11 (that is, controls to change the strength of the jet flow shown in FIG. 2). The vessel control device 13 of the vessel 1 of the second embodiment, like the vessel control device 13 of the vessel 1 of the first embodiment, not only has a normal mode but also a vessel fixed position holding mode. In addition, in the vessel fixed position holding mode, the vessel control device 13 of the vessel 1 of the second embodiment performs feedback control (e.g., PID control) of the engine 11 and the jet propulsion device 12 based on the deviation between a target vessel position, which is a preset target position of the vessel 1, and the actual vessel position.

[0040] FIG. 5 is a diagram for explaining the position of the bucket 12B controlled by the bucket position control unit 13A of the ship control device 13 when the ship control device 13 of the ship 1 of the second embodiment is in the ship fixed position holding mode. In the example shown in Figure 5, when the ship control device 13 is in ship fixed position holding mode, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A of the ship control device 13 are set to a neutral position N, a forward position F, and a linear forward side intermediate position NF that can be linearly adjusted between them. In other words, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A when the ship control device 13 is in ship fixed position holding mode include a neutral position N, a forward position F, and a linear forward intermediate position NF that can be linearly adjusted between them.

[0041] In the example shown in Figure 5, when the ship control device 13 is in a ship fixed position holding mode, the ship control device 13 controls both the position of the bucket 12B (control to place the bucket 12B at either the neutral position N, the linear forward side intermediate position NF, or the forward position F) and the rotational speed of the engine 11. In detail, when the vessel control device 13 is in vessel fixed position holding mode, the vessel control device 13 executes control to set the rotational speed of the engine 11 to a predetermined value and to set the position of the bucket 12B to one of the forward position F, neutral position N, and linear forward side intermediate position NF so that the vessel 1 is held at a fixed position at the target vessel position.

[0042] [Table 2]

[0043] Table 2 shows an example of the correspondence between the rotation speed of the engine 11, the position of the bucket 12B, and the like when the vessel control device 13 of the vessel 1 of the second embodiment is in the vessel fixed position holding mode. In the example shown in Table 2, when the deviation between the target vessel position and the actual vessel position is zero in the vessel fixed position mode of the vessel control device 13, the control amount (feedback control amount) calculated by the vessel control device 13 becomes zero. As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the neutral position N. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE" (the rotation speed of the engine 11 in an idling state). As a result, the jet propulsion device 12 does not generate a propulsive force to move the vessel 1, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 2, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+1" (in other words, when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+1"), the control amount calculated by the vessel control device 13 becomes "+1". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the linear forward side intermediate position NF. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position close to the neutral position N within the linear forward side intermediate position NF. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 forward so as to reduce the deviation from "+1" to zero, and the vessel 1 is maintained at the target vessel position.

[0044] In the example shown in Table 2, when the deviation between the target vessel position and the actual vessel position in the vessel control device 13's fixed vessel position mode is "+2" (> deviation "+1") (in other words, when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+2"), the control amount calculated by the vessel control device 13 becomes "+2" (> control amount "+1"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the linear forward side intermediate position NF. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position between the neutral position N and the forward position F of the linear forward side intermediate position NF. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 forward so as to reduce the deviation from "+2" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 2, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+3" (> deviation "+2") (in other words, when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+3"), the control amount calculated by the vessel control device 13 becomes "+3" (> control amount "+2"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the linear forward side intermediate position NF. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position within the linear forward side intermediate position NF that is closer to the forward position F. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 forward so as to reduce the deviation from "+3" to zero, and the vessel 1 is maintained at the target vessel position.

[0045] In the example shown in Table 2, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+4" (> deviation "+3") (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+4"), the control amount calculated by the vessel control device 13 becomes "+4" (> control amount "+3"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward position F. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+4" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 2, when the deviation between the target vessel position and the actual vessel position in the vessel control device 13's fixed vessel position mode is "+5" (> deviation "+4") (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+5"), the control amount calculated by the vessel control device 13 becomes "+5" (> control amount "+4"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward position F. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+1" (> rotation speed "IDLE" of the engine 11). As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+5" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 2, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+6" (> deviation "+5") (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+6"), the control amount calculated by the vessel control device 13 becomes "+6" (> control amount "+5"). As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward position F. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+2" (> rotation speed of the engine 11 "IDLE+1"). As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+6" to zero, and the vessel 1 is maintained at the target vessel position.

[0046] In the example shown in Table 2, when the vessel control device 13 is in vessel fixed position holding mode, if the position of the bucket 12B is set to the neutral position N, the actual vessel position will be located behind the target vessel position, and if the position of the bucket 12B is set to the forward position F, the actual vessel position will be located ahead of the target vessel position (i.e., if a relatively small rearward external force is applied to the vessel 1), the position of the bucket 12B is set to the linear forward side intermediate position NF, and the rotational speed of the engine 11 is set to "IDLE" so that the vessel 1 is held in a fixed position at the target vessel position.

[0047] In other words, in the example shown in Table 2, the linear forward intermediate position NF is set as the position of the bucket 12B, and when the ship control device 13 is in the ship fixed position holding mode, both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are executed, so that when, for example, the deviation between the target ship position and the actual ship position is "+1," "+2," or "+3," the bucket 12B is positioned at the forward position F, which prevents the ship 1 from moving too far forward of the target ship position. In other words, in the vessel 1 of the second embodiment, the controllability of vessel fixed position holding can be improved compared to when the linear forward side intermediate position NF is not set as the position of the bucket 12B, or when both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are not executed when the vessel control device 13 is in vessel fixed position holding mode.

[0048] In the example shown in Table 2, the rotational speed of the engine 11 is controlled to "IDLE" when the position of the bucket 12B is set to the linear forward side intermediate position NF, but in other examples, the rotational speed of the engine 11 may be controlled to a rotational speed other than "IDLE" (for example, "IDLE+1", "IDLE+2", etc.) when the position of the bucket 12B is set to the linear forward side intermediate position NF. Specifically, when the position of the bucket 12B changes from a position close to the neutral position N of the linear forward side intermediate position NF to a position between the neutral position N and forward position F of the linear forward side intermediate position NF to a position close to forward position F of the linear forward side intermediate position NF, the rotational speed of the engine 11 may be changed, for example, from "IDLE" to "IDLE+1" to "IDLE+2".

[0049] <Third embodiment> A third embodiment of the ship, ship control device, ship control method, and program of the present invention will be described below. The boat 1 of the third embodiment is configured similarly to the boat 1 of the first embodiment described above, except for the points described below. Therefore, the boat 1 of the third embodiment can achieve the same effects as the boat 1 of the first embodiment described above, except for the points described below.

[0050] 1, the boat 1 of the third embodiment includes, for example, an engine 11, a jet propulsion device 12, a boat control device 13, a boat position detection unit 14, and an operation unit 15. The bucket 12B of the jet propulsion device 12 of the boat 1 of the third embodiment is configured to be positionable in a forward position F, a neutral position N, and a reverse position R. The bucket position control unit 13A of the ship control device 13 of the ship 1 of the third embodiment controls the position of the bucket 12B (for example, control to position the bucket 12B at a forward position F, control to position the bucket 12B at a neutral position N, control to position the bucket 12B at a reverse position R, etc.). The engine rotation speed control unit 13B of the vessel control device 13 of the vessel 1 of the third embodiment controls the rotation speed of the engine 11 (that is, controls to change the strength of the jet flow shown in FIG. 2). The vessel control device 13 of the vessel 1 of the third embodiment, like the vessel control device 13 of the vessel 1 of the first embodiment, not only has a normal mode but also a vessel fixed position holding mode. In addition, in the vessel fixed position holding mode, the vessel control device 13 of the vessel 1 of the third embodiment performs feedback control (e.g., PID control) of the engine 11 and the jet propulsion device 12 based on the deviation between a target vessel position, which is a preset target position of the vessel 1, and the actual vessel position.

[0051] FIG. 6 is a diagram showing an example of the position of the bucket 12B controlled by the bucket position control unit 13A of the vessel control device 13 when the vessel control device 13 of the vessel 1 according to the third embodiment is in the vessel fixed position holding mode. In the example shown in Figure 6, when the ship control device 13 is in ship fixed position holding mode, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A of the ship control device 13 are set to a neutral position N, a reverse position R, and three reverse side intermediate positions N-1, N-2, and N-3 located between them. In other words, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A when the ship control device 13 is in the ship fixed position holding mode include the neutral position N, the reverse side intermediate position N-1, the reverse side intermediate position N-2, the reverse side intermediate position N-3, and the reverse position R. In the example shown in FIG. 6, three reverse side intermediate positions N-1, N-2, and N-3 are set as the reverse side intermediate positions between the neutral position N and the reverse position R, but in other examples, any number of reverse side intermediate positions other than three may be set as the reverse side intermediate positions between the neutral position N and the reverse position R.

[0052] 6, the rotation angle θ of the bucket 12B required to move the bucket 12B from the neutral position N to the reverse position R is divided into four. In addition, the position where the bucket 12B is rotated by (θ / 4) from the neutral position N is set as the reverse side intermediate position N-1, the position where the bucket 12B is rotated by (2θ / 4) from the neutral position N is set as the reverse side intermediate position N-2, and the position where the bucket 12B is rotated by (3θ / 4) from the neutral position N is set as the reverse side intermediate position N-3. In the example shown in FIG. 6, reverse side intermediate positions N-1, N-2, and N-3 are set at positions obtained by dividing, at equal angular intervals, the rotation angle θ of the bucket 12B required to move the bucket 12B from the neutral position N to the reverse side intermediate position N-1, the rotation angle of the bucket 12B required to move the bucket 12B from the neutral position N to the reverse side intermediate position N-1, the rotation angle of the bucket 12B required to move the bucket 12B from the reverse side intermediate position N-1 to the reverse side intermediate position N-2, the rotation angle of the bucket 12B required to move the bucket 12B from the reverse side intermediate position N-2 to the reverse side intermediate position N-3, and the rotation angle of the bucket 12B required to move the bucket 12B from the reverse side intermediate position N-3 to the reverse side intermediate position R may be different from one another.

[0053] In the example shown in Figure 6, when the ship control device 13 is in a ship fixed position holding mode, the ship control device 13 controls both the position of the bucket 12B (control to place the bucket 12B in any of the neutral position N, the reverse side intermediate positions N-1, N-2, N-3, and the reverse position R) and the rotational speed of the engine 11. In detail, when the vessel control device 13 is in vessel fixed position holding mode, the vessel control device 13 sets the rotational speed of the engine 11 to a predetermined value so that the vessel 1 is held at a fixed position at the target vessel position, and executes control to set the position of the bucket 12B to one of the reverse position R, neutral position N, and three reverse side intermediate positions N-1, N-2, and N-3.

[0054] [Table 3]

[0055] Table 3 shows an example of the correspondence between the rotation speed of the engine 11, the position of the bucket 12B, etc. when the vessel control device 13 of the vessel 1 of the third embodiment is in the vessel fixed position holding mode. In the example shown in Table 3, when the deviation between the target vessel position and the actual vessel position in the vessel control device 13's fixed vessel positioning mode is zero, the control amount (feedback control amount) calculated by the vessel control device 13 becomes zero. As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the neutral position N. Specifically, the bucket position control unit 13A controls the position of the bucket 12B to the neutral position N even if the shift operation unit 15B does not accept an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE" (the rotation speed of the engine 11 in an idling state). Specifically, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. Therefore, the jet propulsion device 12 does not generate a propulsive force to move the vessel 1, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 3, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-1" (i.e., when the actual vessel position is shifted forward of the vessel 1 from the target vessel position by an amount equivalent to the deviation "-1"), the control amount calculated by the vessel control device 13 becomes "-1". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the astern side intermediate position N-1. Specifically, the bucket position control unit 13A controls the position of the bucket 12B to the astern side intermediate position N-1 even if the shift operation unit 15B does not accept an input operation from the vessel operator. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". Specifically, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to change the deviation from "-1" to zero, and the vessel 1 is maintained at the target vessel position.

[0056] In the example shown in Table 3, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-2" (i.e., when the actual vessel position is shifted forward of the vessel 1 from the target vessel position by an amount equivalent to the deviation "-2"), the control amount calculated by the vessel control device 13 becomes "-2". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the astern side intermediate position N-2. In detail, the bucket position control unit 13A controls the position of the bucket 12B to the astern side intermediate position N-2 even if the shift operation unit 15B does not accept an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-2" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 3, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-3" (i.e., when the actual vessel position is shifted forward of the vessel 1 from the target vessel position by an amount equivalent to the deviation "-3"), the control amount calculated by the vessel control device 13 becomes "-3". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the astern side intermediate position N-3. Specifically, the bucket position control unit 13A controls the position of the bucket 12B to the astern side intermediate position N-3 even if the shift operation unit 15B does not accept an input operation from the vessel operator. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". Specifically, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-3" to zero, and the vessel 1 is maintained at the target vessel position.

[0057] In the example shown in Table 3, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-4" (i.e., when the actual vessel position is shifted forward of the vessel 1 with respect to the target vessel position by an amount equivalent to the deviation "-4"), the control amount calculated by the vessel control device 13 becomes "-4". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the reverse position R. In detail, the bucket position control unit 13A controls the position of the bucket 12B to the reverse position R even if the shift operation unit 15B does not receive an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE" even if the throttle operation unit 15A does not receive an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-4" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 3, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-5" (i.e., when the actual vessel position is shifted forward of the vessel 1 with respect to the target vessel position by an amount equivalent to the deviation "-5"), the control amount calculated by the vessel control device 13 becomes "-5". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the reverse position R. In detail, the bucket position control unit 13A controls the position of the bucket 12B to the reverse position R even if the shift operation unit 15B does not accept an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+1" (> rotation speed of the engine 11 "IDLE"). In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE+1" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-5" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 3, when the deviation between the target vessel position and the actual vessel position in the vessel stationary position mode of the vessel control device 13 is "-6" (i.e., when the actual vessel position is shifted forward of the vessel 1 from the target vessel position by an amount equivalent to the deviation "-6"), the control amount calculated by the vessel control device 13 becomes "-6". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the reverse position R. In detail, the bucket position control unit 13A controls the position of the bucket 12B to the reverse position R even if the shift operation unit 15B does not accept an input operation from the vessel operator. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+2" (> rotation speed of the engine 11 "IDLE+1"). In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE+2" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-6" to zero, and the vessel 1 is maintained at the target vessel position.

[0058] In the example shown in Table 3, when the vessel control device 13 is in vessel fixed position holding mode, if the position of the bucket 12B is set to the neutral position N, the actual vessel position will be located further forward than the target vessel position, and if the position of the bucket 12B is set to the reverse position R, the actual vessel position will be located further aft than the target vessel position (i.e., if a relatively small forward external force is applied to the vessel 1), the position of the bucket 12B is set to, for example, the reverse side intermediate position N-1, the reverse side intermediate position N-2, the reverse side intermediate position N-3, etc., and the rotational speed of the engine 11 is set to "IDLE" so that the vessel 1 is held in a fixed position at the target vessel position.

[0059] In other words, in the example shown in Table 3, the position of the bucket 12B is set to the intermediate positions N-1, N-2, and N-3 on the reversing side, and when the ship control device 13 is in the ship fixed position holding mode, both the control of the position of the bucket 12B and the control of the rotational speed of the engine 11 are executed, so that, for example, when the deviation between the target ship position and the actual ship position is "-1," "-2," or "-3," the bucket 12B is positioned in the reversing position R, which prevents the ship 1 from moving too far rearward of the target ship position. In other words, in the vessel 1 of the third embodiment, the controllability of vessel fixed positioning can be improved compared to when the reverse side intermediate positions N-1, N-2, and N-3 are not set as the position of the bucket 12B, or when both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are not executed when the vessel control device 13 is in vessel fixed positioning mode.

[0060] In the example shown in Table 3, the rotational speed of the engine 11 is controlled to "IDLE" when the position of the bucket 12B is set to the reverse side intermediate positions N-1, N-2, and N-3, but in other examples, the rotational speed of the engine 11 may be controlled to a rotational speed other than "IDLE" (for example, "IDLE+1," "IDLE+2," etc.) when the position of the bucket 12B is set to the reverse side intermediate positions N-1, N-2, and N-3. Specifically, when the position of the bucket 12B changes from the reverse side intermediate position N-1 to the reverse side intermediate position N-2 to the reverse side intermediate position N-3, the rotational speed of the engine 11 may be changed, for example, from "IDLE" to "IDLE+1" to "IDLE+2."

[0061] FIG. 7 is a flowchart illustrating an example of processing executed by the vessel control device 13 of the vessel 1 according to the third embodiment. 7, in step S30, the ship control device 13 determines whether it is in ship fixed position mode (determines whether it is in ship fixed position mode or normal mode). If the ship control device 13 is in ship fixed position mode, the process proceeds to step S31, and if the ship control device 13 is in normal mode, the process proceeds to step S32. In step S31, the vessel control device 13 executes feedback control of the engine 11 and the jet propulsion device 12 based on the deviation between the target vessel position and the actual vessel position. In detail, the vessel control device 13 executes control to maintain the vessel 1 at the target vessel position (performs fixed position maintenance of the vessel 1). Specifically, in step S31A, the bucket position control unit 13A of the vessel control device 13 controls the position of the bucket 12B. In the example shown in Fig. 6 described above, the positions of the bucket 12B include the neutral position N, the reverse position R, and the reverse side intermediate positions N-1, N-2, and N-3. In addition, in step S31B, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11. That is, when step S31 is executed, both the control of the position of the bucket 12B including the reverse side intermediate positions N-1, N-2, and N-3 and the control of the rotation speed of the engine 11 are executed. In step S32, the vessel control device 13 executes control in the normal mode. Specifically, the bucket position control unit 13A controls the position of the bucket 12B to one of the forward position F, the neutral position N, and the reverse position R, based on the input operation of the vessel operator received by the shift operation unit 15B. In addition, the engine rotation speed control unit 13B controls the rotation speed of the engine 11, based on the input operation of the vessel operator received by the throttle operation unit 15A.

[0062] <Fourth embodiment> A fourth embodiment of the ship, ship control device, ship control method, and program of the present invention will be described below. The boat 1 of the fourth embodiment is configured similarly to the boat 1 of the first embodiment described above, except for the points described below. Therefore, the boat 1 of the fourth embodiment can achieve the same effects as the boat 1 of the first embodiment described above, except for the points described below.

[0063] 1, the boat 1 of the fourth embodiment includes, for example, an engine 11, a jet propulsion device 12, a boat control device 13, a boat position detection unit 14, and an operation unit 15. The bucket 12B of the jet propulsion device 12 of the boat 1 of the fourth embodiment is configured to be positionable in a forward position F, a neutral position N, and a reverse position R. The bucket position control unit 13A of the ship control device 13 of the ship 1 of the fourth embodiment controls the position of the bucket 12B (for example, control to position the bucket 12B at a forward position F, control to position the bucket 12B at a neutral position N, control to position the bucket 12B at a reverse position R, etc.). The engine rotation speed control unit 13B of the vessel control device 13 of the vessel 1 of the fourth embodiment controls the rotation speed of the engine 11 (that is, controls to change the strength of the jet flow shown in FIG. 2). The vessel control device 13 of the vessel 1 of the fourth embodiment, like the vessel control device 13 of the vessel 1 of the first embodiment, not only has a normal mode but also a vessel fixed position holding mode. In addition, in the vessel fixed position holding mode, the vessel control device 13 of the vessel 1 of the fourth embodiment performs feedback control (e.g., PID control) of the engine 11 and the jet propulsion device 12 based on the deviation between a target vessel position, which is a preset target position of the vessel 1, and the actual vessel position.

[0064] FIG. 8 is a diagram for explaining the position of the bucket 12B controlled by the bucket position control unit 13A of the ship control device 13 when the ship control device 13 of the ship 1 of the fourth embodiment is in the ship fixed position holding mode. In the example shown in Figure 8, when the ship control device 13 is in ship fixed position holding mode, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A of the ship control device 13 are set to a neutral position N, a reverse position R, and a linear reverse side intermediate position NR that can be linearly adjusted between them. In other words, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A when the ship control device 13 is in ship fixed position holding mode include a neutral position N, a reverse position R, and a linear reverse side intermediate position NR that can be linearly adjusted between them.

[0065] In the example shown in Figure 8, when the ship control device 13 is in a ship fixed position holding mode, the ship control device 13 controls both the position of the bucket 12B (control to place the bucket 12B in any of the neutral position N, the linear reverse side intermediate position NR, and the reverse position R) and the rotational speed of the engine 11. In detail, when the vessel control device 13 is in vessel fixed position holding mode, the vessel control device 13 sets the rotational speed of the engine 11 to a predetermined value so that the vessel 1 is held at a fixed position at the target vessel position, and executes control to set the position of the bucket 12B to one of the reverse position R, neutral position N, and linear reverse side intermediate position NR.

[0066] [Table 4]

[0067] Table 4 shows an example of the correspondence between the rotation speed of the engine 11, the position of the bucket 12B, etc. when the vessel control device 13 of the vessel 1 of the fourth embodiment is in the vessel fixed position holding mode. In the example shown in Table 4, when the deviation between the target vessel position and the actual vessel position is zero in the vessel fixed position holding mode of the vessel control device 13, the control amount (feedback control amount) calculated by the vessel control device 13 becomes zero. As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the neutral position N. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE" (the rotation speed of the engine 11 in an idling state). As a result, the jet propulsion device 12 does not generate a propulsive force to move the vessel 1, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 4, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-1" (that is, when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-1"), the control amount calculated by the vessel control device 13 becomes "-1". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the linear reverse side intermediate position NR. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position close to the neutral position N within the linear reverse side intermediate position NR. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 astern in order to reduce the deviation from "-1" to zero, and the vessel 1 is maintained at the target vessel position.

[0068] In the example shown in Table 4, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-2" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-2"), the control amount calculated by the vessel control device 13 becomes "-2". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B at the linear reverse side intermediate position NR. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position between the neutral position N and the reverse position R of the linear reverse side intermediate position NR. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 astern in order to reduce the deviation from "-2" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 4, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-3" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-3"), the control amount calculated by the vessel control device 13 becomes "-3". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B at the linear reverse side intermediate position NR. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position within the linear reverse side intermediate position NR that is closer to the reverse position R. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force that moves the vessel 1 astern in order to reduce the deviation from "-3" to zero, and the vessel 1 is maintained at the target vessel position.

[0069] In the example shown in Table 4, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-4" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-4"), the control amount calculated by the vessel control device 13 becomes "-4". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in astern position R. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-4" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 4, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-5" (i.e., when the actual vessel position is shifted forward of the vessel 1 relative to the target vessel position by an amount equivalent to the deviation "-5"), the control amount calculated by the vessel control device 13 becomes "-5". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the astern position R. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+1" (> rotation speed "IDLE" of the engine 11). As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "-5" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 4, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-6" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-6"), the control amount calculated by the vessel control device 13 becomes "-6". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in astern position R. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+2" (> rotation speed of the engine 11 "IDLE+1"). As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-6" to zero, and the vessel 1 is maintained at the target vessel position.

[0070] In the example shown in Table 4, when the vessel control device 13 is in vessel fixed position holding mode, if the position of the bucket 12B is set to the neutral position N, the actual vessel position will be located forward of the target vessel position, and if the position of the bucket 12B is set to the reverse position R, the actual vessel position will be located rearward of the target vessel position (i.e., if a relatively small forward external force is applied to the vessel 1), the position of the bucket 12B is set to the linear reverse side intermediate position NR, and the rotational speed of the engine 11 is set to "IDLE" so that the vessel 1 is held fixed at the target vessel position.

[0071] In other words, in the example shown in Table 4, the linear reverse side intermediate position NR is set as the position of the bucket 12B, and when the ship control device 13 is in the ship fixed position holding mode, both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are executed, so that, for example, when the deviation between the target ship position and the actual ship position is "-1," "-2," or "-3," the bucket 12B is positioned in the reverse position R, which prevents the ship 1 from moving too far rearward of the target ship position. In other words, in the ship 1 of the fourth embodiment, the controllability of ship fixed positioning can be improved compared to when the linear reverse side intermediate position NR is not set as the position of the bucket 12B, or when both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are not executed when the ship control device 13 is in ship fixed positioning mode.

[0072] In the example shown in Table 4, the rotational speed of the engine 11 is controlled to "IDLE" when the position of the bucket 12B is set to the linear reverse side intermediate position NR, but in other examples, the rotational speed of the engine 11 may be controlled to a rotational speed other than "IDLE" (for example, "IDLE+1," "IDLE+2," etc.) when the position of the bucket 12B is set to the linear reverse side intermediate position NR. Specifically, when the position of the bucket 12B changes from a position close to the neutral position N of the linear reverse side intermediate position NR to a position between the neutral position N and the reverse position R of the linear reverse side intermediate position NR to a position close to the reverse position R of the linear reverse side intermediate position NR, the rotational speed of the engine 11 may be changed, for example, from "IDLE" to "IDLE+1" to "IDLE+2."

[0073] Fifth Embodiment A fifth embodiment of a ship, a ship control device, a ship control method, and a program according to the present invention will be described below. The boat 1 of the fifth embodiment is configured similarly to the boat 1 of the first embodiment described above, except for the points described below. Therefore, the boat 1 of the fifth embodiment can achieve the same effects as the boat 1 of the first embodiment described above, except for the points described below.

[0074] 1, the boat 1 of the fifth embodiment includes, for example, an engine 11, a jet propulsion device 12, a boat control device 13, a boat position detection unit 14, and an operation unit 15. The bucket 12B of the jet propulsion device 12 of the boat 1 of the fifth embodiment is configured to be positionable in a forward position F, a neutral position N, and a reverse position R. The bucket position control unit 13A of the ship control device 13 of the ship 1 of the fifth embodiment controls the position of the bucket 12B (for example, control to position the bucket 12B at a forward position F, control to position the bucket 12B at a neutral position N, control to position the bucket 12B at a reverse position R, etc.). The engine rotation speed control unit 13B of the vessel control device 13 of the vessel 1 of the fifth embodiment controls the rotation speed of the engine 11 (that is, controls to change the strength of the jet flow shown in FIG. 2). The vessel control device 13 of the vessel 1 of the fifth embodiment, like the vessel control device 13 of the vessel 1 of the first embodiment, not only has a normal mode but also a vessel fixed position holding mode. In addition, in the vessel fixed position holding mode, the vessel control device 13 of the vessel 1 of the fifth embodiment performs feedback control (e.g., PID control) of the engine 11 and the jet propulsion device 12 based on the deviation between a target vessel position, which is a preset target position of the vessel 1, and the actual vessel position.

[0075] In the ship 1 of the fifth embodiment, when the ship control device 13 is in a ship fixed position holding mode, the positions of the bucket 12B that can be set by the bucket position control unit 13A of the ship control device 13 include a forward position F (see Figure 3), a neutral position N (see Figures 3 and 6), three forward intermediate positions N+1, N+2, and N+3 (see Figure 3) located therebetween, a reverse position R (see Figure 6), and three reverse intermediate positions N-1, N-2, and N-3 (see Figure 6) located between the neutral position N and the reverse position R. In one example of the marine vessel 1 of the fifth embodiment (the example shown in Figure 3), three forward intermediate positions N+1, N+2, and N+3 are set as forward intermediate positions between the neutral position N and the forward position F, but in other examples of the marine vessel 1 of the fifth embodiment, any number of forward intermediate positions other than three may be set as forward intermediate positions between the neutral position N and the forward position F. In one example of the vessel 1 of the fifth embodiment (the example shown in Figure 6), three reverse side intermediate positions N-1, N-2, and N-3 are set as reverse side intermediate positions between the neutral position N and the reverse position R, but in other examples of the vessel 1 of the fifth embodiment, any number of reverse side intermediate positions other than three may be set as reverse side intermediate positions between the neutral position N and the reverse position R.

[0076] 3, in the vessel 1 of the fifth embodiment, the rotation angle θ of the bucket 12B required to move the bucket 12B from the neutral position N to the forward position F is divided into four. Furthermore, the position where the bucket 12B is rotated by (θ / 4) from the neutral position N is set as a forward-side intermediate position N+1, the position where the bucket 12B is rotated by (2θ / 4) from the neutral position N is set as a forward-side intermediate position N+2, and the position where the bucket 12B is rotated by (3θ / 4) from the neutral position N is set as a forward-side intermediate position N+3. In one example of the marine vessel 1 of the fifth embodiment (the example shown in FIG. 3 ), forward movement side intermediate positions N+1, N+2, and N+3 are set at positions obtained by dividing, at equal angular intervals, the rotation angle θ of the bucket 12B required to move the bucket 12B from the neutral position N to the forward movement side intermediate position N+1, the rotation angle of the bucket 12B required to move the bucket 12B from the neutral position N to the forward movement side intermediate position N+1, the rotation angle of the bucket 12B required to move the bucket 12B from the forward movement side intermediate position N+1 to the forward movement side intermediate position N+2, the rotation angle of the bucket 12B required to move the bucket 12B from the forward movement side intermediate position N+2 to the forward movement side intermediate position N+3, and the rotation angle of the bucket 12B required to move the bucket 12B from the forward movement side intermediate position N+3 to the forward movement side intermediate position N+3 to the forward movement side position F may be different from one another.

[0077] 6, in the vessel 1 of the fifth embodiment, the rotation angle θ of the bucket 12B required to move the bucket 12B from the neutral position N to the reverse position R is divided into four. Furthermore, the position where the bucket 12B is rotated by (θ / 4) from the neutral position N is set as the reverse side intermediate position N-1, the position where the bucket 12B is rotated by (2θ / 4) from the neutral position N is set as the reverse side intermediate position N-2, and the position where the bucket 12B is rotated by (3θ / 4) from the neutral position N is set as the reverse side intermediate position N-3. In one example of the marine vessel 1 of the fifth embodiment (the example shown in FIG. 6 ), the reverse side intermediate positions N-1, N-2, and N-3 are set at positions obtained by dividing, at equal angular intervals, the rotation angle θ of the bucket 12B required to move the bucket 12B from the neutral position N to the reverse side intermediate position N-1, the rotation angle of the bucket 12B required to move the bucket 12B from the neutral position N to the reverse side intermediate position N-1, the rotation angle of the bucket 12B required to move the bucket 12B from the reverse side intermediate position N-1 to the reverse side intermediate position N-2, the rotation angle of the bucket 12B required to move the bucket 12B from the reverse side intermediate position N-2 to the reverse side intermediate position N-3, and the rotation angle of the bucket 12B required to move the bucket 12B from the reverse side intermediate position N-3 to the reverse side intermediate position N-3 to the reverse position R may be different from one another.

[0078] In the ship 1 of the fifth embodiment, when the ship control device 13 is in a ship fixed position holding mode, the ship control device 13 controls both the position of the bucket 12B (control to place the bucket 12B in any of the forward position F, forward intermediate positions N+1, N+2, N+3, neutral position N, reverse intermediate positions N-1, N-2, N-3, and reverse position R) and the rotational speed of the engine 11. In detail, when the vessel control device 13 is in vessel fixed position holding mode, the vessel control device 13 sets the rotational speed of the engine 11 to a predetermined value so that the vessel 1 is held at a fixed position at the target vessel position, and executes control to set the position of the bucket 12B to one of the forward position F, three forward intermediate positions N+1, N+2, N+3, neutral position N, three reverse intermediate positions N-1, N-2, N-3, and reverse position R.

[0079] [Table 5]

[0080] Table 5 shows an example of the correspondence between the rotation speed of the engine 11, the position of the bucket 12B, etc. when the ship control device 13 is in the ship fixed position holding mode. In the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-6" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-6"), the control amount calculated by the vessel control device 13 becomes "-6". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in astern position R. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+2". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-6" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-5" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-5"), the control amount calculated by the vessel control device 13 becomes "-5". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in astern position R. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+1". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-5" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-4" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-4"), the control amount calculated by the vessel control device 13 becomes "-4". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the astern position R. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-4" to zero, and the vessel 1 is maintained at the target vessel position.

[0081] In the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-3" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-3"), the control amount calculated by the vessel control device 13 becomes "-3". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the astern side intermediate position N-3. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-3" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-2" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-2"), the control amount calculated by the vessel control device 13 becomes "-2". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the astern intermediate position N-2. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-2" to zero, and the vessel 1 is maintained at the target vessel position.

[0082] In the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-1" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-1"), the control amount calculated by the vessel control device 13 becomes "-1". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the astern side intermediate position N-1. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-1" to zero, and the vessel 1 is maintained at the target vessel position.

[0083] In the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position is zero in the vessel fixed position mode of the vessel control device 13, the control amount (feedback control amount) calculated by the vessel control device 13 becomes zero. As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the neutral position N. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE" (the rotation speed of the engine 11 in an idling state). As a result, the jet propulsion device 12 does not generate a propulsive force to move the vessel 1, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+1" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+1"), the control amount calculated by the vessel control device 13 becomes "+1". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward intermediate position N+1. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+1" to zero, and the vessel 1 is maintained at the target vessel position.

[0084] In the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+2" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+2"), the control amount calculated by the vessel control device 13 becomes "+2". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward intermediate position N+2. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+2" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+3" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+3"), the control amount calculated by the vessel control device 13 becomes "+3". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward intermediate position N+3. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+3" to zero, and the vessel 1 is maintained at the target vessel position.

[0085] In the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel control device 13's fixed vessel position mode is "+4" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+4"), the control amount calculated by the vessel control device 13 becomes "+4". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at forward position F. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+4" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+5" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+5"), the control amount calculated by the vessel control device 13 becomes "+5". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the forward position F. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+1". In detail, the engine rotation speed control unit 13B controls the rotation speed of the engine 11 to "IDLE+1" even if the throttle operation unit 15A does not accept an input operation from the vessel operator. As a result, the jet propulsion device 12 generates a propulsive force that moves the vessel 1 forward so as to reduce the deviation from "+5" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 5, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+6" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+6"), the control amount calculated by the vessel control device 13 becomes "+6". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at forward position F. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+2". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+6" to zero, and the vessel 1 is maintained at the target vessel position.

[0086] In the example shown in Table 5, when the vessel control device 13 is in vessel fixed position holding mode, if the position of the bucket 12B is set to the neutral position N, the actual vessel position will be located further aft than the target vessel position, and if the position of the bucket 12B is set to the forward drive position F, the actual vessel position will be located further forward than the target vessel position (i.e., if a relatively small rearward external force is applied to the vessel 1), the position of the bucket 12B is set to, for example, forward side intermediate position N+1, forward side intermediate position N+2, forward side intermediate position N+3, etc., and the rotational speed of the engine 11 is set to "IDLE" so that the vessel 1 is held in a fixed position at the target vessel position. Furthermore, in the example shown in Table 5, when the vessel control device 13 is in vessel fixed position holding mode, if the position of the bucket 12B is set to the neutral position N, the actual vessel position will be located further forward than the target vessel position, and if the position of the bucket 12B is set to the reverse position R, the actual vessel position will be located further aft than the target vessel position (i.e., if a relatively small forward external force is applied to the vessel 1), the position of the bucket 12B is set to, for example, the reverse side intermediate position N-1, the reverse side intermediate position N-2, the reverse side intermediate position N-3, etc., and the rotational speed of the engine 11 is set to "IDLE" so that the vessel 1 is held in a fixed position at the target vessel position.

[0087] In other words, in the example shown in Table 5, the position of the bucket 12B is set to forward intermediate positions N+1, N+2, N+3 and rear intermediate positions N-1, N-2, N-3, and when the ship control device 13 is in a fixed ship position holding mode, both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are executed. Therefore, for example, when the deviation between the target ship position and the actual ship position is "+1," "+2," or "+3," the ship 1 can be prevented from moving too far forward of the target ship position when the bucket 12B is positioned in the forward position F, and for example, when the deviation between the target ship position and the actual ship position is "-1," "-2," or "-3," the ship 1 can be prevented from moving too far rearward of the target ship position when the bucket 12B is positioned in the reverse position R. In other words, in the ship 1 of the fifth embodiment, the controllability of ship fixed positioning can be improved compared to when the forward side intermediate positions N+1, N+2, N+3 are not set as the position of the bucket 12B, when the reverse side intermediate positions N-1, N-2, N-3 are not set as the position of the bucket 12B, or when both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are not executed when the ship control device 13 is in ship fixed positioning mode.

[0088] In the example shown in Table 5, the rotational speed of the engine 11 is controlled to "IDLE" when the position of the bucket 12B is set to forward-side intermediate positions N+1, N+2, and N+3, but in other examples, the rotational speed of the engine 11 may be controlled to a rotational speed other than "IDLE" (for example, "IDLE+1," "IDLE+2," etc.) when the position of the bucket 12B is set to forward-side intermediate positions N+1, N+2, and N+3. Specifically, when the position of the bucket 12B changes from forward-side intermediate position N+1 to forward-side intermediate position N+2 to forward-side intermediate position N+3, the rotational speed of the engine 11 may be changed, for example, from "IDLE" to "IDLE+1" to "IDLE+2." Furthermore, in the example shown in Table 5, the rotational speed of the engine 11 is controlled to "IDLE" when the position of the bucket 12B is set to the reverse side intermediate positions N-1, N-2, and N-3, but in other examples, the rotational speed of the engine 11 may be controlled to a rotational speed other than "IDLE" (for example, "IDLE+1," "IDLE+2," etc.) when the position of the bucket 12B is set to the reverse side intermediate positions N-1, N-2, and N-3. Specifically, when the position of the bucket 12B changes from the reverse side intermediate position N-1 to the reverse side intermediate position N-2 to the reverse side intermediate position N-3, the rotational speed of the engine 11 may be changed, for example, from "IDLE" to "IDLE+1" to "IDLE+2."

[0089] FIG. 9 is a flowchart illustrating an example of processing executed by the vessel control device 13 of the vessel 1 according to the fifth embodiment. 9, in step S50, the ship control device 13 determines whether it is in ship fixed position mode (determines whether it is in ship fixed position mode or normal mode). If the ship control device 13 is in ship fixed position mode, the process proceeds to step S51, and if the ship control device 13 is in normal mode, the process proceeds to step S52. In step S51, the vessel control device 13 executes feedback control of the engine 11 and the jet propulsion device 12 based on the deviation between the target vessel position and the actual vessel position. In detail, the vessel control device 13 executes control to keep the vessel 1 at the target vessel position (holds the vessel 1 at a fixed position). Specifically, in step S51A, the bucket position control unit 13A of the vessel control device 13 controls the position of the bucket 12B. In the example shown in Table 5 above, the positions of the bucket 12B include forward position F, forward side intermediate positions N+1, N+2, N+3, neutral position N, reverse position R, and reverse side intermediate positions N-1, N-2, N-3. In addition, in step S51B, the engine rotation speed control unit 13B of the vessel control device 13 executes control of the rotation speed of the engine 11. In other words, when step S51 is executed, both control of the position of the bucket 12B, including the forward intermediate positions N+1, N+2, N+3 and the reverse intermediate positions N-1, N-2, N-3, and control of the rotational speed of the engine 11 are executed. In step S52, the vessel control device 13 executes control in the normal mode. Specifically, the bucket position control unit 13A controls the position of the bucket 12B to one of the forward position F, the neutral position N, and the reverse position R, based on the input operation of the vessel operator received by the shift operation unit 15B. In addition, the engine rotation speed control unit 13B controls the rotation speed of the engine 11, based on the input operation of the vessel operator received by the throttle operation unit 15A.

[0090] Sixth Embodiment A sixth embodiment of a ship, a ship control device, a ship control method, and a program according to the present invention will now be described. The boat 1 of the sixth embodiment is configured similarly to the boat 1 of the first embodiment described above, except for the points described below. Therefore, the boat 1 of the sixth embodiment can achieve the same effects as the boat 1 of the first embodiment described above, except for the points described below.

[0091] 1, the boat 1 of the sixth embodiment includes, for example, an engine 11, a jet propulsion device 12, a boat control device 13, a boat position detection unit 14, and an operation unit 15. The bucket 12B of the jet propulsion device 12 of the boat 1 of the sixth embodiment is configured to be positionable in a forward position F, a neutral position N, and a reverse position R. The bucket position control unit 13A of the ship control device 13 of the ship 1 of the sixth embodiment controls the position of the bucket 12B (for example, control to position the bucket 12B at a forward position F, control to position the bucket 12B at a neutral position N, control to position the bucket 12B at a reverse position R, etc.). The engine rotation speed control unit 13B of the vessel control device 13 of the vessel 1 of the sixth embodiment controls the rotation speed of the engine 11 (that is, controls to change the strength of the jet flow shown in FIG. 2). The vessel control device 13 of the vessel 1 of the sixth embodiment, like the vessel control device 13 of the vessel 1 of the first embodiment, not only has a normal mode but also a vessel fixed position holding mode. In addition, in the vessel fixed position holding mode, the vessel control device 13 of the vessel 1 of the sixth embodiment performs feedback control (e.g., PID control) of the engine 11 and the jet propulsion device 12 based on the deviation between a target vessel position, which is a preset target position of the vessel 1, and the actual vessel position.

[0092] In the ship 1 of the sixth embodiment, when the ship control device 13 is in a ship fixed position holding mode, the positions of the bucket 12B that can be set by the bucket position control unit 13A of the ship control device 13 include a forward position F (see Figure 5), a neutral position N (see Figures 5 and 8), a linear forward side intermediate position NF (see Figure 5) that is linearly position adjustable between them, a reverse position R (see Figure 8), and a linear reverse side intermediate position NR (see Figure 8) that is linearly position adjustable between the neutral position N and the reverse position R. In other words, the positions of the bucket 12B that can be positioned by the bucket position control unit 13A when the ship control device 13 is in ship fixed position holding mode include a forward position F, a neutral position N, a linear forward side intermediate position NF therebetween, a reverse position R, and a linear reverse side intermediate position NR between the neutral position N and the reverse position R.

[0093] In the vessel 1 of the sixth embodiment, when the vessel control device 13 is in a vessel fixed position holding mode, the vessel control device 13 controls both the position of the bucket 12B (control to place the bucket 12B in any of the forward position F, the linear forward side intermediate position NF, the neutral position N, the linear reverse side intermediate position NR, and the reverse position R) and the rotational speed of the engine 11. In detail, when the vessel control device 13 is in vessel fixed position holding mode, the vessel control device 13 sets the rotational speed of the engine 11 to a predetermined value so that the vessel 1 is held at a fixed position at the target vessel position, and executes control to set the position of the bucket 12B to one of the forward position F, linear forward side intermediate position NF, neutral position N, linear reverse side intermediate position NR, and reverse position R.

[0094] [Table 6]

[0095] Table 6 shows an example of the correspondence between the rotation speed of the engine 11, the position of the bucket 12B, etc. when the vessel control device 13 of the vessel 1 of the sixth embodiment is in the vessel fixed position holding mode.

[0096] In the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-6" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-6"), the control amount (feedback control amount) calculated by the vessel control device 13 becomes "-6". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in astern position R. In addition, the engine rotation speed control unit 13B of the vessel control device 13 sets the rotation speed of the engine 11 to "IDLE+2". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern in order to reduce the deviation from "-6" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-5" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-5"), the control amount calculated by the vessel control device 13 becomes "-5". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the astern position R. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+1". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "-5" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-4" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-4"), the control amount calculated by the vessel control device 13 becomes "-4". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the astern position R. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 astern so as to reduce the deviation from "-4" to zero, and the vessel 1 is maintained at the target vessel position.

[0097] In the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-3" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-3"), the control amount calculated by the vessel control device 13 becomes "-3". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B at the linear reverse side intermediate position NR. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position within the linear reverse side intermediate position NR that is closer to the reverse position R. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force that moves the vessel 1 astern in order to reduce the deviation from "-3" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-2" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-2"), the control amount calculated by the vessel control device 13 becomes "-2". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B at the linear reverse side intermediate position NR. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position between the neutral position N and the reverse position R of the linear reverse side intermediate position NR. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 astern in order to reduce the deviation from "-2" to zero, and the vessel 1 is maintained at the target vessel position.

[0098] In the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "-1" (i.e., when the actual vessel position is shifted forward of the target vessel position by an amount equivalent to the deviation "-1"), the control amount calculated by the vessel control device 13 becomes "-1". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B at the linear reverse side intermediate position NR. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position close to the neutral position N within the linear reverse side intermediate position NR. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 astern in order to reduce the deviation from "-1" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position is zero in the vessel fixed position mode of the vessel control device 13, the control amount calculated by the vessel control device 13 becomes zero. As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B in the neutral position N. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE." Therefore, the jet propulsion device 12 does not generate a propulsive force to move the vessel 1, and the vessel 1 is maintained at the target vessel position.

[0099] In the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+1" (in other words, when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+1"), the control variable calculated by the vessel control device 13 becomes "+1". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B at the linear forward side intermediate position NF. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position close to the neutral position N within the linear forward side intermediate position NF. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 forward so as to reduce the deviation from "+1" to zero, and the vessel 1 is maintained at the target vessel position.

[0100] In the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+2" (in other words, when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+2"), the control amount calculated by the vessel control device 13 becomes "+2". As a result, the bucket position control unit 13A of the vessel control device 13 places the bucket 12B at the linear forward side intermediate position NF. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position between the neutral position N and the forward position F of the linear forward side intermediate position NF. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 forward so as to reduce the deviation from "+2" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+3" (in other words, when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+3"), the control amount calculated by the vessel control device 13 becomes "+3". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at the linear forward side intermediate position NF. In detail, the bucket position control unit 13A adjusts the position of the bucket 12B to a position within the linear forward side intermediate position NF that is closer to the forward position F. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force for moving the vessel 1 forward so as to reduce the deviation from "+3" to zero, and the vessel 1 is maintained at the target vessel position.

[0101] In the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+4" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+4"), the control amount calculated by the vessel control device 13 becomes "+4". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at forward position F. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+4" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel control device 13's vessel fixed position mode is "+5" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+5"), the control amount calculated by the vessel control device 13 becomes "+5". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at forward position F. Furthermore, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+1". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+5" to zero, and the vessel 1 is maintained at the target vessel position. Furthermore, in the example shown in Table 6, when the deviation between the target vessel position and the actual vessel position in the vessel fixed position mode of the vessel control device 13 is "+6" (i.e., when the actual vessel position is shifted aft of the target vessel position by an amount equivalent to the deviation "+6"), the control amount calculated by the vessel control device 13 becomes "+6". As a result, the bucket position control unit 13A of the vessel control device 13 positions the bucket 12B at forward position F. In addition, the engine rotation speed control unit 13B of the vessel control device 13 controls the rotation speed of the engine 11 to "IDLE+2". As a result, the jet propulsion device 12 generates a propulsive force to move the vessel 1 forward so as to reduce the deviation from "+6" to zero, and the vessel 1 is maintained at the target vessel position.

[0102] In the example shown in Table 6, when the vessel control device 13 is in vessel fixed position holding mode, if the position of the bucket 12B is set to the neutral position N, the actual vessel position will be located behind the target vessel position, and if the position of the bucket 12B is set to the forward position F, the actual vessel position will be located ahead of the target vessel position (i.e., if a relatively small rearward external force is applied to the vessel 1), the position of the bucket 12B is set to the linear forward side intermediate position NF, and the rotational speed of the engine 11 is set to "IDLE" so that the vessel 1 is held in a fixed position at the target vessel position. Furthermore, in the example shown in Table 6, when the vessel control device 13 is in vessel fixed position holding mode, if the position of the bucket 12B is set to the neutral position N, the actual vessel position will be located forward of the target vessel position, and if the position of the bucket 12B is set to the reverse position R, the actual vessel position will be located rearward of the target vessel position (i.e., if a relatively small forward external force is applied to the vessel 1), the position of the bucket 12B is set to the linear reverse side intermediate position NR, and the rotational speed of the engine 11 is set to "IDLE" so that the vessel 1 is held in a fixed position at the target vessel position.

[0103] In other words, in the example shown in Table 6, the position of the bucket 12B is set to the linear forward intermediate position NF and the linear reverse intermediate position NR, and when the ship control device 13 is in the ship fixed position holding mode, both the control of the position of the bucket 12B and the control of the rotational speed of the engine 11 are executed.Therefore, for example, when the deviation between the target ship position and the actual ship position is "+1," "+2," or "+3," the ship 1 can be prevented from moving too far forward of the target ship position when the bucket 12B is positioned in the forward position F, and for example, when the deviation between the target ship position and the actual ship position is "-1," "-2," or "-3," the ship 1 can be prevented from moving too far rearward of the target ship position when the bucket 12B is positioned in the reverse position R. In other words, in the vessel 1 of the sixth embodiment, the controllability of vessel fixed position holding can be improved compared to when the linear forward side intermediate position NF is not set as the position of the bucket 12B, when the linear reverse side intermediate position NR is not set as the position of the bucket 12B, or when both control of the position of the bucket 12B and control of the rotational speed of the engine 11 are not executed when the vessel control device 13 is in vessel fixed position holding mode.

[0104] In the example shown in Table 6, the rotational speed of the engine 11 is controlled to "IDLE" when the position of the bucket 12B is set to the linear forward side intermediate position NF, but in other examples, the rotational speed of the engine 11 may be controlled to a rotational speed other than "IDLE" (for example, "IDLE+1", "IDLE+2", etc.) when the position of the bucket 12B is set to the linear forward side intermediate position NF. Specifically, when the position of the bucket 12B changes from a position close to the neutral position N of the linear forward side intermediate position NF to a position between the neutral position N and forward position F of the linear forward side intermediate position NF to a position close to forward position F of the linear forward side intermediate position NF, the rotational speed of the engine 11 may be changed, for example, from "IDLE" to "IDLE+1" to "IDLE+2". Furthermore, in the example shown in Table 6, the rotational speed of the engine 11 is controlled to "IDLE" when the position of the bucket 12B is set to the linear reverse side intermediate position NR, but in other examples, the rotational speed of the engine 11 may be controlled to a rotational speed other than "IDLE" (for example, "IDLE+1," "IDLE+2," etc.) when the position of the bucket 12B is set to the linear reverse side intermediate position NR. Specifically, when the position of the bucket 12B changes from a position close to the neutral position N of the linear reverse side intermediate position NR to a position between the neutral position N and reverse position R of the linear reverse side intermediate position NR to a position close to reverse position R of the linear reverse side intermediate position NR, the rotational speed of the engine 11 may be changed, for example, from "IDLE" to "IDLE+1" to "IDLE+2."

[0105] Seventh Embodiment A seventh embodiment of a ship, a ship control device, a ship control method, and a program according to the present invention will now be described. The boat 1 of the seventh embodiment is configured similarly to the boats 1 of the first to sixth embodiments described above, except for the points described below. Therefore, the boat 1 of the seventh embodiment can achieve the same effects as the boats 1 of the first to sixth embodiments described above, except for the points described below.

[0106] As described above, the vessels 1 in the first to sixth embodiments are PWCs, but the vessel 1 in the seventh embodiment is a vessel having basic functions similar to those of a sports boat, for example, as described in Figure 1 of JP 2020-019321 A.

[0107] Figures 10 to 12 are diagrams showing examples of control that can be implemented in the vessel 1 of the first to seventh embodiments. In detail, Figure 10(A) shows the relationship between the vessel and the holding OK area, etc. at the start of control to keep the vessel in the holding OK area. Figure 10(B) shows the relationship between the vessel and the holding OK area, etc. when the vessel's position has changed due to an external disturbance. Figure 11(A) shows the vessel turning so that the stern of the vessel, whose position has changed due to an external disturbance, is directed toward the target coordinates. Figure 11(B) shows how the vessel's position, whose stern is directed toward the target coordinates, changes again due to the disturbance. Figure 12 shows how throttle control (regression control) is performed until the vessel enters the holding OK area. In the examples shown in Figures 10 to 12, when the ship control device 13 of the ship 1 of the first to seventh embodiments is in ship fixed point holding mode, a "target coordinate," a "holding OK area" including the "target coordinate," a "heading control area" around the "holding OK area," and a "return control area" around the "heading control area" are set. In detail, in the examples shown in Figures 10 to 12, the coordinates indicating the position of the ship at the start of control to keep the ship in the holding OK area are set as the "target coordinates," as shown in Figure 10(A). As shown in Figure 10(B), when a disturbance causes the vessel to move from the "holding OK area" to the "heading control area," the vessel is turned so that the stern of the vessel faces the "target coordinates," as shown in Figure 11(A). In another example, the vessel may be turned so that the bow of the vessel faces the "target coordinates." As shown in Figure 11(B), when an external disturbance causes the ship to move from the "heading control area" to the "return control area," throttle control (return control) is executed to bring the ship into the "holding OK area," as shown in Figure 12.

[0108] Figures 13 to 15 are diagrams showing other examples of control that can be performed in the vessel 1 of the first to seventh embodiments. In detail, Figure 13(A) shows the relationship between the vessel and the holding OK area, etc. at the start of control to keep the vessel in the holding OK area. Figure 13(B) shows the relationship between the vessel and the holding OK area, etc. when the vessel's position has changed due to a disturbance. Figure 14(A) shows the vessel turning so that the stern of the vessel, whose position has changed due to a disturbance, is directed toward the target coordinates. Figure 14(B) shows how the vessel's position, whose stern is directed toward the target coordinates, changes again due to the disturbance. Figure 15 shows how throttle control (regression control) is performed until the vessel enters the holding OK area. In the examples shown in Figures 13 to 15, when the ship control device 13 of the ship 1 of the first to seventh embodiments is in ship fixed point holding mode, a "target coordinate," a "holding OK area" including the "target coordinate," and a "return control area" around the "holding OK area" are set. In detail, in the examples shown in Figures 13 to 15, the coordinates indicating the position of the ship at the start of control to keep the ship in the holding OK area are set as the "target coordinates", as shown in Figure 13(A). As shown in Figure 13(B), when the position of the vessel deviates from the "target coordinates" due to an external disturbance, even if the position of the vessel is within the "holding OK area", the vessel is turned so that the stern of the vessel faces the "target coordinates", as shown in Figure 14(A). In another example, the vessel may be turned so that the bow of the vessel faces the "target coordinates". As shown in FIG. 14(B), when the vessel moves into the "regression control area" due to a disturbance, throttle control (regression control) is executed to bring the vessel into the "holding OK area" as shown in FIG.

[0109] Although the present invention has been described above using the embodiments, the present invention is not limited to these embodiments, and various modifications and substitutions can be made without departing from the spirit of the present invention. The configurations described in the above-described embodiments and examples may be combined.

[0110] Note that all or part of the functions of each unit of the vessel 1 in the above-described embodiment may be realized by recording a program for realizing these functions on a computer-readable recording medium, and reading and executing the program recorded on the recording medium into a computer system. Note that the term "computer system" here includes hardware such as an OS and peripheral devices. Furthermore, "computer-readable recording media" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage units such as hard disks built into computer systems. Furthermore, "computer-readable recording media" may also include devices that dynamically store programs for a short period of time, such as communication lines when transmitting programs over networks like the Internet or communication lines like telephone lines, or devices that store programs for a fixed period of time, such as volatile memory within computer systems that serve as servers or clients in such cases. Furthermore, the above-mentioned programs may be programs that realize some of the aforementioned functions, or may be programs that can realize the aforementioned functions in combination with programs already stored in the computer system. [Explanation of symbols]

[0111] 1...ship, 11...engine, 12...jet propulsion device, 12A...nozzle, 12B...bucket, 13...ship control device, 13A...bucket position control section, 13B...engine rotation speed control section, 14...ship position detection section, 15...operation section, 15A...throttle operation section, 15B...shift operation section

Claims

1. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and a vessel control device that controls the engine and the jet propulsion device; an operation unit that accepts input operations from a vessel operator; The ship includes a ship position detection unit that detects an actual ship position, which is an actual position of the ship, The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; and a forward intermediate position between the forward position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, The ship control device a normal mode in which the position of the bucket and the rotation speed of the engine are controlled in response to an input operation of the operation unit by a vessel operator; a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position; During the vessel fixed position holding mode, both the control of the position of the bucket including the forward side intermediate position and the control of the rotational speed of the engine are executed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; When the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the forward intermediate position and the engine is set to the idle rotation speed; If the deviation is a second predetermined value, the bucket is positioned at the forward position and the engine is at the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is positioned at the forward position and the engine is rotated at a speed greater than the idle speed. ship.

2. the forward-side intermediate positions between the forward position and the neutral position include a plurality of forward-side intermediate positions, The control executed by the vessel control device during the vessel fixed position keeping mode includes: and a control for setting the engine to the idle rotation speed and setting the position of the bucket to any one of the forward position, the neutral position, and the plurality of forward-side intermediate positions so that the vessel is maintained at a fixed position at a target vessel position.

2. The watercraft of claim 1.

3. the forward intermediate position between the forward position and the neutral position includes a linear forward intermediate position that is linearly position-adjustable, The control executed by the vessel control device during the vessel fixed position keeping mode includes: and a control for setting the engine to the idle rotation speed and adjusting the linear forward intermediate position so that the vessel is maintained at a fixed position at a target vessel position.

2. The watercraft of claim 1.

4. In the vessel fixed position holding mode, if the position of the bucket is set to the neutral position, the actual vessel position will be located aft of the target vessel position, or if the position of the bucket is set to the forward position, the actual vessel position will be located forward of the target vessel position. The position of the bucket is set to the forward intermediate position, the engine is set to the idle rotational speed so that the vessel is stationary at a target vessel position; 4. A vessel according to claim 2 or claim 3.

5. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and a vessel control device that controls the engine and the jet propulsion device; an operation unit that accepts input operations from a vessel operator; The ship includes a ship position detection unit that detects an actual ship position, which is an actual position of the ship, The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; a reverse position in which the jet propulsion device generates a propulsive force that moves the vessel backward; and a reverse intermediate position between the reverse position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, The ship control device a normal mode in which the position of the bucket and the rotation speed of the engine are controlled in response to an input operation of the operation unit by a vessel operator; a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position; During the vessel fixed position holding mode, both the control of the position of the bucket including the reverse side intermediate position and the control of the rotational speed of the engine are executed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; When the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the reverse side intermediate position and the engine is set to the idle rotation speed; If the deviation is equal to a second predetermined value, the bucket is positioned in the reverse position and the engine is set to the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is moved to the reverse position and the engine is rotated at a speed greater than the idle speed. ship.

6. the reverse side intermediate position between the reverse position and the neutral position includes a plurality of reverse side intermediate positions, The control executed by the vessel control device during the vessel fixed position keeping mode includes: and a control for setting the engine to the idle rotation speed and setting the position of the bucket to one of the reverse drive position, the neutral position, and the plurality of reverse side intermediate positions so that the vessel is kept at a fixed position at a target vessel position.

6. A watercraft according to claim 5.

7. the reverse-side intermediate position between the reverse position and the neutral position includes a linear reverse-side intermediate position that is linearly position-adjustable, The control executed by the vessel control device during the vessel fixed position keeping mode includes: a control for setting the engine to the idle rotation speed and adjusting the linear reverse side intermediate position so that the vessel is maintained at a fixed position at a target vessel position; 6. A watercraft according to claim 5.

8. In the vessel fixed position holding mode, if the position of the bucket is set to the neutral position, the actual vessel position will be located forward of the target vessel position, or if the position of the bucket is set to the astern position, the actual vessel position will be located aft of the target vessel position, The position of the bucket is set to the reverse side intermediate position, the engine is set to the idle rotational speed so that the vessel is stationary at a target vessel position; 8. A vessel according to claim 6 or claim 7.

9. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and a vessel control device that controls the engine and the jet propulsion device; an operation unit that accepts input operations from a vessel operator; The ship includes a ship position detection unit that detects an actual ship position, which is an actual position of the ship, The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; a reverse position in which the jet propulsion device generates a propulsive force that moves the vessel backward; a forward intermediate position between the forward position and the neutral position; and a reverse intermediate position between the reverse position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, The ship control device a normal mode in which the position of the bucket and the rotation speed of the engine are controlled in response to an input operation of the operation unit by a vessel operator; a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position; During the vessel fixed position holding mode, both of the control of the bucket position including the forward side intermediate position and the reverse side intermediate position and the control of the engine rotation speed are executed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; when the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the forward intermediate position or the reverse intermediate position, and the engine is set to the idle rotation speed; If the deviation is a second predetermined value, the bucket is positioned at the forward position or the reverse position and the engine is set to the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is moved to the forward position or the reverse position, and the engine is rotated at a speed greater than the idle speed. ship.

10. the forward-side intermediate positions between the forward position and the neutral position include a plurality of forward-side intermediate positions, the reverse side intermediate position between the reverse position and the neutral position includes a plurality of reverse side intermediate positions, The control executed by the vessel control device during the vessel fixed position keeping mode includes: and a control for setting the engine to the idle rotation speed and setting the position of the bucket to any one of the forward position, the neutral position, the reverse position, the plurality of forward side intermediate positions, and the plurality of reverse side intermediate positions so that the vessel is maintained at a fixed position at a target vessel position.

10. The watercraft of claim 9.

11. the forward intermediate position between the forward position and the neutral position includes a linear forward intermediate position that is linearly position-adjustable, the reverse-side intermediate position between the reverse position and the neutral position includes a linear reverse-side intermediate position that is linearly position-adjustable, The control executed by the vessel control device during the vessel fixed position keeping mode includes: and a control for setting the engine to the idle rotation speed and adjusting the linear forward-side intermediate position and the linear reverse-side intermediate position so that the vessel is maintained at a fixed position at a target vessel position.

10. The watercraft of claim 9.

12. In the vessel fixed position holding mode, if the position of the bucket is set to the neutral position, the actual vessel position will be located aft of the target vessel position, and if the position of the bucket is set to the forward position, the actual vessel position will be located forward of the target vessel position. The position of the bucket is set to the forward intermediate position, the engine is set to the idle rotational speed so that the vessel is stationary at a target vessel position; 12. A vessel according to claim 10 or claim 11.

13. In the vessel fixed position holding mode, if the position of the bucket is set to the neutral position, the actual vessel position will be located forward of the target vessel position, and if the position of the bucket is set to the astern position, the actual vessel position will be located aft of the target vessel position. The position of the bucket is set to the reverse side intermediate position, the engine is set to the idle rotational speed so that the vessel is stationary at a target vessel position; 12. A vessel according to claim 10 or claim 11.

14. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and an operation unit that accepts input operations from a vessel operator; a vessel position detection unit that detects an actual vessel position, which is an actual position of the vessel; The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; and a forward intermediate position between the forward position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, the vessel control device controls a position of the bucket and a rotation speed of the engine in accordance with an input operation of the operation unit by a vessel operator; a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position; During the vessel fixed position holding mode, both of the control of the position of the bucket including the forward side intermediate position and the control of the rotational speed of the engine are performed without requiring an input operation of the operation unit by the vessel operator; and If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; When the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the forward intermediate position and the engine is set to the idle rotation speed; If the deviation is a second predetermined value, the bucket is positioned at the forward position and the engine is at the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is positioned at the forward position and the engine is rotated at a speed greater than the idle speed. Ship control equipment.

15. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and an operation unit that accepts input operations from a vessel operator; a vessel position detection unit that detects an actual vessel position, which is an actual position of the vessel; The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; a reverse position in which the jet propulsion device generates a propulsive force that moves the vessel backward; and a reverse intermediate position between the reverse position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, The ship control device a normal mode in which the position of the bucket and the rotation speed of the engine are controlled in response to an input operation of the operation unit by a vessel operator; a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position; During the vessel fixed position holding mode, both of the control of the position of the bucket including the reverse side intermediate position and the control of the rotational speed of the engine are performed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; When the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the reverse side intermediate position and the engine is set to the idle rotation speed; If the deviation is equal to a second predetermined value, the bucket is positioned in the reverse position and the engine is set to the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is moved to the reverse position and the engine is rotated at a speed greater than the idle speed. Ship control equipment.

16. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and an operation unit that accepts input operations from a vessel operator; a vessel position detection unit that detects an actual vessel position, which is an actual position of the vessel; The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; a reverse position in which the jet propulsion device generates a propulsive force that moves the vessel backward; a forward intermediate position between the forward position and the neutral position; and a reverse intermediate position between the reverse position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, The ship control device a normal mode in which the position of the bucket and the rotation speed of the engine are controlled in response to an input operation of the operation unit by a vessel operator; a vessel fixed position holding mode in which feedback control of the engine and the jet propulsion device is performed based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position; During the vessel fixed position holding mode, both of the control of the bucket position including the forward side intermediate position and the reverse side intermediate position and the control of the engine rotation speed are performed without requiring an input operation of the operation unit by the vessel operator; If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; when the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the forward intermediate position or the reverse intermediate position, and the engine is set to the idle rotation speed; If the deviation is a second predetermined value, the bucket is positioned at the forward position or the reverse position and the engine is set to the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is moved to the forward position or the reverse position, and the engine is rotated at a speed greater than the idle speed. Ship control equipment.

17. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and an operation unit that accepts input operations from a vessel operator; A ship control method for controlling a ship including a ship position detection unit that detects an actual ship position, which is an actual position of the ship, comprising: The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; and a forward intermediate position between the forward position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, a normal control step of controlling the position of the bucket and the rotational speed of the engine in response to an input operation of the operation unit by a vessel operator; a vessel fixed position maintaining step of performing feedback control of the engine and the jet propulsion device based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position, When the vessel fixed position maintaining step is performed, both the control of the position of the bucket including the forward side intermediate position and the control of the rotational speed of the engine are performed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; When the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the forward intermediate position and the engine is set to the idle rotation speed; If the deviation is a second predetermined value, the bucket is positioned at the forward position and the engine is at the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is positioned at the forward position and the engine is rotated at a speed greater than the idle speed. Ship control methods.

18. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and an operation unit that accepts input operations from a vessel operator; A ship control method for controlling a ship including a ship position detection unit that detects an actual ship position, which is an actual position of the ship, comprising: The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; a reverse position in which the jet propulsion device generates a propulsive force that moves the vessel backward; and a reverse intermediate position between the reverse position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, a normal control step of controlling the position of the bucket and the rotational speed of the engine in response to an input operation of the operation unit by a vessel operator; a vessel fixed position maintaining step of performing feedback control of the engine and the jet propulsion device based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position, When the vessel fixed position maintaining step is performed, both the control of the position of the bucket including the reverse side intermediate position and the control of the rotational speed of the engine are performed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; When the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the reverse side intermediate position and the engine is set to the idle rotation speed; If the deviation is equal to a second predetermined value, the bucket is positioned in the reverse position and the engine is set to the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is moved to the reverse position and the engine is rotated at a speed greater than the idle speed. Ship control methods.

19. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel using the driving force output from the engine; and an operation unit that accepts input operations from a vessel operator; A ship control method for controlling a ship including a ship position detection unit that detects an actual ship position, which is an actual position of the ship, comprising: The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; a reverse position in which the jet propulsion device generates a propulsive force that moves the vessel backward; a forward intermediate position between the forward position and the neutral position; and a reverse intermediate position between the reverse position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, a normal control step of controlling the position of the bucket and the rotational speed of the engine in response to an input operation of the operation unit by a vessel operator; a vessel fixed position maintaining step of performing feedback control of the engine and the jet propulsion device based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position, When the vessel fixed position maintaining step is performed, both of the control of the bucket position including the forward side intermediate position and the reverse side intermediate position and the control of the engine rotation speed are performed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; when the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the forward intermediate position or the reverse intermediate position, and the engine is set to the idle rotation speed; If the deviation is a second predetermined value, the bucket is positioned at the forward position or the reverse position and the engine is set to the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is moved to the forward position or the reverse position, and the engine is rotated at a speed greater than the idle speed. Ship control methods.

20. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel, the jet propulsion device including a nozzle that emits a jet stream generated by the driving force output from the engine, and a bucket that changes the direction of the jet stream emitted from the nozzle; an operation unit that accepts input operations from a vessel operator; a computer mounted on the ship, the computer comprising a ship position detection unit for detecting an actual ship position, the actual position of the ship; a normal control step of controlling the position of the bucket and the rotational speed of the engine in response to an input operation of the operation unit by a vessel operator; a ship fixed position maintaining step for performing feedback control of the engine and the jet propulsion device based on a deviation between a target ship position, which is a preset target position of the ship, and an actual ship position, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; and a forward intermediate position between the forward position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, When the vessel fixed position maintaining step is performed, both the control of the position of the bucket including the forward side intermediate position and the control of the rotational speed of the engine are performed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; When the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the forward intermediate position and the engine is set to the idle rotation speed; If the deviation is a second predetermined value, the bucket is positioned at the forward position and the engine is at the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is positioned at the forward position and the engine is rotated at a speed greater than the idle speed. program.

21. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel, the jet propulsion device including a nozzle that emits a jet stream generated by the driving force output from the engine, and a bucket that changes the direction of the jet stream emitted from the nozzle; an operation unit that accepts input operations from a vessel operator; a computer mounted on the ship, the computer comprising a ship position detection unit for detecting an actual ship position, the actual position of the ship; a normal control step of controlling the position of the bucket and the rotational speed of the engine in response to an input operation of the operation unit by a vessel operator; a program for executing a vessel fixed position maintaining step for performing feedback control of the engine and the jet propulsion device based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position, the program comprising: The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; a reverse position in which the jet propulsion device generates a propulsive force that moves the vessel backward; and a reverse intermediate position between the reverse position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, When the vessel fixed position maintaining step is performed, both the control of the position of the bucket including the reverse side intermediate position and the control of the rotational speed of the engine are performed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; When the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the reverse side intermediate position and the engine is set to the idle rotation speed; If the deviation is equal to a second predetermined value, the bucket is positioned in the reverse position and the engine is set to the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is moved to the reverse position and the engine is rotated at a speed greater than the idle speed. program.

22. an engine that outputs driving force; a jet propulsion device that generates a propulsive force for the vessel, the jet propulsion device including a nozzle that emits a jet stream generated by the driving force output from the engine, and a bucket that changes the direction of the jet stream emitted from the nozzle; an operation unit that accepts input operations from a vessel operator; a computer mounted on the ship, the computer comprising a ship position detection unit for detecting an actual ship position, the actual position of the ship; a normal control step of controlling the position of the bucket and the rotational speed of the engine in response to an input operation of the operation unit by a vessel operator; a program for executing a vessel fixed position maintaining step for performing feedback control of the engine and the jet propulsion device based on a deviation between a target vessel position, which is a preset target position of the vessel, and an actual vessel position, the program comprising: The jet propulsion device a nozzle that ejects a jet flow generated by the driving force output from the engine; a bucket for changing the direction of the jet flow ejected from the nozzle, The bucket position is a forward position where the jet propulsion device generates a propulsive force that moves the vessel forward; a neutral position in which the jet propulsion device does not generate a propulsive force for moving the vessel; a reverse position in which the jet propulsion device generates a propulsive force that moves the vessel backward; a forward intermediate position between the forward position and the neutral position; and a reverse intermediate position between the reverse position and the neutral position, The rotational speed of the engine includes: Idle rotation speed, which is the rotation speed in an idling state; and a rotation speed greater than the idle rotation speed, When the vessel fixed position maintaining step is performed, both of the control of the bucket position including the forward side intermediate position and the reverse side intermediate position and the control of the engine rotation speed are performed without requiring an input operation of the operation unit by the vessel operator, If the deviation is smaller than a first predetermined value, the bucket is positioned at the neutral position and the engine is at the idle rotation speed; when the deviation is equal to or greater than a first predetermined value and smaller than a second predetermined value that is greater than the first predetermined value, the bucket is positioned at the forward intermediate position or the reverse intermediate position, and the engine is set to the idle rotation speed; If the deviation is a second predetermined value, the bucket is positioned at the forward position or the reverse position and the engine is set to the idle rotation speed; If the deviation is greater than a second predetermined value, the bucket is moved to the forward position or the reverse position, and the engine is rotated at a speed greater than the idle speed. program.

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