The present invention relates to a hull attitude control apparatus.
In the related art, various techniques have been proposed that prevent a hull from shaking or moving at the time of anchorage. For example, a technique is disclosed in which a stabilization fin is provided on the hull (for example, refer to Patent Document 1 (Published Japanese Translation No. 2019-529225 of the PCT International Publication)).
In this technique, when the hull begins to shake, the stabilization fin is operated. Thereby, a force that acts on the hull cancels a force in the shake direction of the hull, and it is possible to prevent shaking of the hull.
However, in the related art described above, there is a problem that since it is necessary to provide the stabilization fin in order to prevent shaking of the hull, manufacturing costs and the weight of the hull are increased. There is a problem that even in the case of preventing the movement of the hull, it is necessary to provide an additional mechanism. As a result, there is a problem that it is difficult to improve the energy efficiency for ensuring access to sustainable and advanced energy.
Accordingly, the present invention provides a hull attitude control apparatus that can prevent shaking or the movement of the hull and can contribute to the improvement of the energy efficiency while minimizing the increase of manufacturing costs and the weight as much as possible.
In order to solve the problems described above, the present invention proposes the following means.
By such a configuration, it is possible to prevent shaking or the movement of the hull by the thrust force of the propeller of the outboard engine. Therefore, an additional mechanism for preventing shaking or movement of the hull as in the related art is not required, and it is possible to prevent shaking of the hull while minimizing the increase of manufacturing costs and the weight of the hull attitude control apparatus as much as possible. By preventing shaking of the hull, it is also possible to prevent the movement of the hull at the time of anchorage.
Since it is possible to minimize the increase of manufacturing costs and the weight of the hull attitude control apparatus as much as possible, it is possible to contribute to the improvement of the energy efficiency.
By such a configuration, particularly when shaking of the hull is prevented, the direction of the thrust force generated by the propeller can be close to an upward-downward direction. Therefore, shaking of the hull is easily prevented.
By such a configuration, it is possible to reliably and efficiently prevent shaking or the movement of the hull, and it is possible to contribute to the improvement of the energy efficiency.
By such a configuration, it is possible to quickly prevent shaking or the movement of the hull.
By such a configuration, it is possible to further quickly and continuously prevent shaking of the hull.
By such a configuration, it is possible to effectively prevent the movement of the hull at the time of anchorage, and it is possible to contribute to the improvement of the energy efficiency.
By such a configuration, the operation of the outboard engine is decreased as much as possible, it is possible to efficiently prevent the movement of the hull at the time of anchorage, and it is possible to contribute to the improvement of the energy efficiency.
By such a configuration, the tilt-up position can be positioned as high as possible in a range in which the propeller can be submerged in water. When the tilt-up position is positioned as high as possible, the propeller rotation axis line can be aligned along the upward-downward direction as much as possible. That is, the thrust force generated by the propeller can be aligned along the upward-downward direction as much as possible. As a result, shaking of the hull can be efficiently prevented by the thrust force of the propeller, and it is possible to contribute the improvement of the energy efficiency.
By such a configuration, the outboard engine can have a simple structure, and it is possible to prevent shaking or the movement of the hull by a simple control.
By such a configuration, it is possible to detect shaking of the hull with high accuracy.
By such a configuration, it is possible to increase variations of means that detect shaking of the hull.
By such a configuration, it is possible to predict shaking of the hull.
By such a configuration, it is possible to increase variations of means that detect shaking of the hull.
By such a configuration, it is possible to increase variations of means that detect shaking of the hull.
By such a configuration, it is possible to increase variations of means that detect shaking of the hull.
According to the present invention, it is possible to prevent shaking or the movement of the hull by the hull attitude control apparatus, and it is possible to contribute to the improvement of the energy efficiency while minimizing the increase of manufacturing costs and the weight of the hull attitude control apparatus as much as possible.
Next, an embodiment of the present invention will be described with reference to the drawings.
As shown in
The hull attitude control apparatus 1 includes: an outboard engine 3 that is provided on the stem 2a of the hull 2; an attitude control portion 4 that performs an attitude control of the outboard engine 3; a shake detection sensor 19 that detects shaking of the hull 2; and an outboard engine control portion 20 that performs an overall drive control of the outboard engine 3.
The outboard engine 3 includes an upper unit 5 that is attached to the hull 2 and a lower unit 6 that is attached to the upper unit 5.
The upper unit 5 includes a cowl 7 that is attached to the stern 2a via a bracket 8 so as to be tiltable (tilt-up enabled) in an upward-downward direction. The bracket 8 includes, for example, a base portion 8a by which the width direction of the hull 2 is a rotational axis line S10. The upper unit 5 is fixed to the base portion 8a.
The upper unit 5 tilts in the upward-downward direction relative to the hull 2 so as to rotate around the rotation axis line S10 of the bracket 8. That is, when the upper unit 5 is located at a lower position (indicated by a two-dot chain line in
From this state, when the upper unit 5 is rotated so as to separate from the stern 2a, the upper unit 5 is moved upward (refer to an arrow Y1 in
Such tilting of the outboard engine 3 (tilting of the cowl 7) is performed by a hydraulic cylinder 17 and the bracket 8 that constitute part of the attitude control portion 4. The hydraulic cylinder 17 is an actuator that is provided on the hull 2. However, the embodiment is not limited thereto, and the hydraulic cylinder 17 may be provided in the cowl 7 of the upper unit 5. Further, an electric motor may be used instead of the hydraulic cylinder 17. The bracket 8 is driven by the drive of the hydraulic cylinder 17, and the outboard engine 3 is tilted. A detailed configuration of the attitude control portion 4 will be described later.
Further, a propeller drive motor 9 and a head oscillation drive motor 10 are stored in the cowl 7. The propeller drive motor 9 is an electric motor for rotationally driving a propeller 12 described later of the lower unit 6. The head oscillation drive motor 10 constitutes part of the attitude control portion 4. The head oscillation drive motor 10 is an electric motor for rotationally driving a casing 11 (described later) of the lower unit 6. The propeller drive motor 9 and the head oscillation drive motor 10 are tilted integrally with the cowl 7 relative to the hull 2.
The lower unit 6 is provided on a lower portion of the upper unit 5 at the tilt-down position TDp. The lower unit 6 includes, at the tilt-down position TDp, a casing 11 that is provided at a lower portion of the cowl 7 and a propeller 12 that is rotatably supported by the casing 11.
The casing 11 is attached at the tilt-down position TDp rotatably around a lower unit rotation axis line S1 along the upward-downward direction relative to the upper unit 5. Since the upward-downward direction is also an alignment direction of the upper unit 5 and the lower unit 6, the lower unit rotation axis line S1 is also in parallel with the alignment direction of the upper unit 5 and the lower unit 6. Such a rotational drive of the casing 11 around the lower unit rotation axis line S1 is performed by the head oscillation drive motor 10. A gear portion 13 for transmitting the rotation of the electric motor 9 to the propeller 12 is stored in the casing 11.
The propeller 12 includes a boss portion 14 having a cylindrical shape, a propeller shaft 15 that is provided in the boss portion 14 and rotates integrally with the boss portion 14, and a plurality of wing portions 16 that are provided around the boss portion 14. A propeller rotation axis line S2 of the propeller 12 (an axis line of the propeller shaft 15) is orthogonal to the lower unit rotation axis line S1. That is, at the tilt-down position TDp, the propeller rotation axis line S2 is along the horizontal direction.
At the tilt-down position TDp, the propeller 12 is offset further rearward than the lower unit rotation axis line S1. In other words, the position of the wing portion 16 is offset further rearward than the lower unit rotation axis line S1. In the propeller 12, the rotation of the electric motor 9 is transmitted to the propeller shaft 15 via the gear portion 13. Thereby, the propeller 12 is rotated, and a thrust force is generated at the hull 2. The propeller 12 is rotatable forward and backward, and the hull 2 is advanced or retracted depending on the rotation direction of the propeller 12.
The attitude control portion 4 includes: an inclination angle sensor 21 that detects a tilt-up angle (inclination angle) of the outboard engine 3; and a rotation position sensor 22 that detects the rotation position of the lower unit 6 relative to the upper unit 5 in addition to the bracket 8, the head oscillation drive motor 10, and the hydraulic cylinder 17. The inclination angle sensor 21 is provided, for example, on the base portion 8a of the bracket 8.
The inclination angle sensor 21 detects an inclination angle of the base portion 8a. An attachment position of the inclination angle sensor 21 is not limited to the base portion 8a. For example, the inclination angle sensor 21 may be provided in the cowl 7. In this case, the inclination angle sensor 21 detects an inclination angle of the cowl 7 (outboard engine 3). The inclination angle sensor 21 may have a configuration that detects a tilt-up angle of the outboard engine 3. For example, the tilt-up angle of the outboard engine 3 may be detected by the stroke amount of the hydraulic cylinder 17. Further, for example, when the electric motor is used instead of the hydraulic cylinder 17, the rotation position of a motor shaft of the electric motor may be detected, and the tilt-up angle may be obtained based on this detection result.
Here, by the tilt-up angle changing, the inclination angle of the propeller rotation axis line S2 also changes. That is, the inclination angle sensor 21 detects the inclination angle of the propeller rotation axis line S2.
A detection result of the inclination angle sensor 21 is output as a signal to the outboard engine control portion 20. The outboard engine control portion 20 performs a drive control of the hydraulic cylinder 17 on the basis of the detection result of the inclination angle sensor 21. Thereby, the tilt-up angle (the inclination angle of the propeller rotation axis line S2) of the outboard engine 3 is controlled.
The rotation position sensor 22 detects a rotation position of the motor shaft (not shown) of the head oscillation drive motor 10. However, the rotation position sensor 22 is not limited thereto as long as the rotation position of the lower unit 6 relative to the upper unit 5 can be detected.
Here, the angle (direction) of the propeller rotation axis line S2 also changes by the casing 11 rotating around the lower unit rotation axis line S1. That is, the rotation position sensor 22 detects the inclination angle of the propeller rotation axis line S2.
A detection result of the rotation position sensor 22 is output as a signal to the outboard engine control portion 20. The outboard engine control portion 20 performs a drive control of the head oscillation drive motor 10 on the basis of the detection result of the rotation position sensor 22. Thereby, the rotation position (the inclination angle of the propeller rotation axis line S2) of the lower unit 6 is controlled.
The shake detection sensor 19 is provided on the hull 2. For example, a gyro sensor that detects an angular speed of the hull 2 is used as the shake detection sensor 19. A detection result of the shake detection sensor 19 is output as a signal to the outboard engine control portion 20. The outboard engine control portion 20 obtains an inclination angle of the hull 2 on the basis of the detection result of the shake detection sensor 19 and performs an overall drive control of the motors 9, 10 and the hydraulic cylinder 17. Thereby, shaking and movement at the time of anchorage of the hull 2 is prevented. Hereinafter, an operation of the hull attitude control apparatus 1 is specifically described.
First, the hull 2 is set to an anchorage mode from an operation mode. The operation mode is a mode in which an ignition switch is turned on, and the marine vessel 100 is set to be operable. In the operation mode, the outboard engine 3 is at the tilt-down position TDp. At the tilt-down position TDp, by driving the propeller 12 (the propeller drive motor 9) or performing a head oscillation of the lower unit 6 (driving the head oscillation drive motor 10), the marine vessel 100 is advanced in a desired direction. The propeller 12 is offset further rearward than the lower unit rotation axis line S1.
The anchorage mode is a mode set when, for example, the propeller 12 (propeller drive motor 9) is stopped, and a predetermined period of time elapses in a state where the outboard engine 3 is at the tilt-down position TDp, and the ignition switch is in an ON state. However, the embodiment is not limited thereto, and the set condition of the anchorage mode is varied. For example, the anchorage mode may be set by stopping the propeller 12 (propeller drive motor 9) and turning on an anchorage mode switch (not shown) that is provided on the hull 2 in a state where the ignition switch is an ON state or the like.
When the mode is set to the anchor mode, the outboard engine 3 is tilted upward by the bracket 8 and the hydraulic cylinder 17 (refer to an arrow Y1 in
At this time, the shake (refer to an arrow Y2 in
Then, a thrust force is generated by the propeller 12, the thrust force and a force in the shake direction of the hull 2 cancel each other, and shaking of the hull 2 is prevented. That is, the forward/backward rotation is performed such that the thrust force is generated in a direction opposite to the shake direction of the hull 2. For example, when a bow 2b of the hull 2 floats upward (refer to an arrow Y3 in
Further, it is desirable that the outboard engine control portion 20 changes the thrust force in accordance with the shake speed of the hull 2. That is, the rotation speed of the propeller drive motor 9 (propeller 12) is changed in accordance with the shake speed of the hull 2. Thereby, shaking of the hull 2 is quickly prevented. It is also possible to manually change the rotation speed of the propeller drive motor 9 (propeller 12).
Here, an action by the inversion of the lower unit 6 is described in detail with reference to
As shown in
Therefore, when the lower unit 6 is rotated by 180°, the wing portion 16 can be submerged in the water even if the tilt-up position TUp is higher compared to a case where the lower unit 6 is not rotated by 180°. The wing portion 16 being submerged in the water is a condition for obtaining a thrust force by the propeller 12.
The propeller rotation axis line S2 when the tilt-up position TUp is high is closer to (along) the upward-downward direction compared to a propeller rotation axis line S2′ when the tilt-up position TUp is low. That is, the thrust force generated by the propeller 12 can be aligned along the upward-downward direction as much as possible. As a result, shaking of the hull 2 can be efficiently prevented by the thrust force of the propeller 12.
In this way, the hull attitude control apparatus 1 described above includes the outboard engine 3, the attitude control portion 4, the outboard engine control portion 20, and the shake detection sensor 19. In the anchorage mode, the propeller rotation axis line S2 is in a state of being inclined relative to the horizontal direction by the attitude control portion 4, that is, the outboard engine 3 is in a tilt-up state. Further, the outboard engine control portion 20 performs a drive control of the propeller drive motor 9 on the basis of the detection result of the shake detection sensor 19. Therefore, shaking of the hull 2 can be prevented by using the outboard engine 3. Therefore, an additional mechanism for preventing shaking of the hull 2 as in the related art is not required, and it is possible to prevent shaking of the hull 2 while minimizing the increase of manufacturing costs and the weight of the hull attitude control apparatus 1 as much as possible.
Since it is possible to minimize the increase of manufacturing costs and the weight of the hull attitude control apparatus 1 as much as possible, it is possible to contribute to the improvement of the energy efficiency.
In order to prevent shaking of the hull 2 by the outboard engine 3, a control is performed such that the thrust force is generated in a direction opposite to the shake direction of the hull 2. Therefore, it is possible to reliably and efficiently prevent shaking of the hull, and it is possible to contribute to the improvement of the energy efficiency.
Further, the propeller drive motor 9 (propeller 12) is repeatedly rotated forward and backward in accordance with shaking of the hull 2. Therefore, it is possible to further quickly and continuously prevent shaking of the hull 2.
When the thrust force is changed in accordance with a shake speed of the hull 2, it is possible to further quickly prevent shaking of the hull 2. In this case, the rotation speed of the propeller drive motor 9 (propeller 12) is changed in accordance with the shake speed of the hull 2.
The lower unit 6 of the outboard engine 3 is provided to be rotatable around the lower unit rotation axis line S1 relative to the upper unit 5. The propeller 12 is offset rearward relative to the lower unit rotation axis line S1 at the tilt-down position TDp. When the outboard engine 3 is tilted upward in the anchorage mode, the lower unit 6 is rotated by 180° from the attitude of the operation mode (at the time of traveling).
Therefore, the tilt-up position TUp can be positioned as high as possible in a range in which the propeller 12 (wing portion 16) can be submerged in water. As a result, the thrust force generated by the propeller 12 can be aligned along the upward-downward direction as much as possible. Therefore, shaking of the hull 2 can be efficiently prevented by the thrust force of the propeller 12, and it is possible to contribute to the improvement of energy efficiency.
Next, modification examples of a hull attitude control apparatus 1 are described.
The above embodiment is described using a case in which shaking of the hull 2 is prevented by rotating the propeller drive motor 9 (propeller 12) forward and backward.
However, the embodiment is not limited thereto, and shaking of the hull 2 may be prevented by repeatedly rotating and stopping the propeller drive motor 9 (propeller 12). In this case, the rotation of the propeller drive motor 9 (propeller 12) may be only at least one of forward rotation and backward rotation. Even in such a configuration, it is possible to achieve effects similar to that of the embodiment described above.
The above embodiment is described using a case in which shaking of the hull 2 is detected by the shake detection sensor 19 provided on the hull 2. However, the embodiment is not limited thereto, and it is sufficient that the shake detection sensor 19 is able to detect shaking of the hull 2 as a result. For example, the outboard engine 3 described above is integral with the hull 2. In a structure in which the outboard engine 3 is integral with the hull 2, and the hull 2 and the outboard engine 3 are integrally shaken, the shake of the outboard engine 3 may be detected. Shaking of the outboard engine 3 may be regarded as shaking of the hull 2. In such a case, detecting the shake or the movement of the outboard engine 3 is synonymous with detecting shaking or movement of the hull 2. In such a case, for example, the shake detection sensor 19 may be provided on the outboard engine 3.
The above embodiment is described using a case in which the hull attitude control apparatus 1 includes the shake detection sensor 19 that detects shaking of the hull 2. However, the embodiment is not limited thereto, and the hull attitude control apparatus 1 may include a positioning sensor 23 (refer to
The positioning sensor 23 is a sensor capable of detecting a self-position (positioning information including the latitude and the longitude) by a satellite positioning system (positioning satellite) such as a D-GPS, a GPS, a GLONASS, Hokuto, Galileo, or Michibiki. That is, the positioning sensor 23 receives a satellite signal (a position of the positioning satellite, a transmission time, correction information, and the like) that is transmitted from the positioning satellite and detects the position (for example, the latitude and the longitude) of the hull 2 on the basis of the satellite signal. According to such a positioning sensor 23, it is possible to detect a case in which the hull 2 moves by receiving the influence of waves, wind, or the like in spite of the anchorage mode.
When the movement of the hull 2 is detected, the hull attitude control apparatus 1 may prevent the movement of the hull 2 in addition to preventing shaking of the hull 2. In a case where the movement of the hull 2 is prevented, a control of the tilt-up angle of the outboard engine 3 is performed by the hydraulic cylinder 17, and a head oscillation (driving of the head oscillation drive motor 10) of the lower unit 6 is performed in accordance with the movement direction of the hull 2. Then, a thrust force is generated in a direction opposite to the movement direction of the hull 2 by the propeller 12, and the movement of the hull 2 is prevented.
Further, the drive direction of the lower unit 6 may be only one direction relative to the shake. In this case, the propeller 12 is driven at a time when the thrust force acts in a direction of preventing shaking of the hull 2. The movement of the hull 2 may be prevented by such a method.
Further, by performing the head oscillation control of the lower unit 6 or the drive control of the propeller 12 while maintaining the tilt-down position TDp, the movement of the hull 2 can be prevented.
Further, by changing the tilt-up angle of the outboard engine 3, a load in the direction of preventing shaking of the hull 2 can be differentiated. As a result, a thrust force in a direction of preventing the movement of the hull 2 also changes. Thereby, the movement of the hull 2 may be prevented.
Further, at this time, it is desirable that the outboard engine control portion 20 change the thrust force in accordance with the movement speed of the hull 2 and determine the drive time of the propeller 12. By such a configuration, the hull 2 can be efficiently stopped at a position. Therefore, it is possible to contribute to the improvement of the energy efficiency.
In this way, the control of the inclination angle of the propeller rotation axis line S2 by the attitude control portion 4 includes not only the control of the inclination angle relative to the horizontal direction by the tilt-up but also the control of the inclination angle (head oscillation angle) relative to the forward-rearward direction of the hull 2.
The above embodiment is described using a case in which the hull attitude control apparatus 1 includes one outboard engine 3 that is provided on the stern 2a of hull 2. However, the embodiment is not limited thereto. As shown in
The outboard engine 3 is arranged on both sides in the width direction of the hull 2.
In such a configuration, for example, when the hull 2 is horizontally shaken (rolls) (refer to an arrow Y7 in
Further, for example, the propellers 12 of the outboard engines 3 may be rotated in a direction opposite to each other, and thrust forces in a direction opposite to each other may be generated (for example, refer to arrows Y8 and Y9 in
The above embodiment is described using a case in which the outboard engine 3 is tilted in the upward-downward direction so as to rotate around the rotation axis line S10 parallel to the width direction of the hull 2 by the bracket 8 and the hydraulic cylinder 17. However, the embodiment is not limited thereto. As shown in
In such a case, even when the lower unit 6 is only inverted, the propeller 12 of each outboard engine 3 can generate not only a thrust force in the upward-downward direction but also a thrust force in a lateral direction that intersects the upward-downward direction. Therefore, both of the two outboard engines 3 can have a role of preventing shaking of the hull 2 and a role of preventing the movement of the hull 2 (refer to arrows Y13 in
The above embodiment is described using a case in which shaking or movement of the hull 2 is prevented by rotating the propeller 12 (propeller drive motor 9) forward and backward or by changing the rotation speed of the propeller 12 (propeller drive motor 9). However, the embodiment is not limited thereto. Shaking or movement of the hull 2 may be prevented by setting the rotation of the propeller 12 (propeller drive motor 9) to be constant and controlling only the inclination angle of the propeller rotation axis line S2.
The above embodiment is described using a case in which the propeller rotation axis line S2 is inclined relative to the horizontal direction by tilting the outboard engine 3 by the hydraulic cylinder 17 and the bracket 8. However, the embodiment is not limited thereto. The upper unit 5 of the outboard engine 3 may be fixed, and the lower unit 6 may be provided to be tiltable in the upward-downward direction relative to the upper unit 5 and to be capable of performing the head oscillation in the horizontal direction. That is, it is sufficient that only the inclination angle of the propeller rotation axis line S2 can be controlled while the lower unit rotation axis line S1 is fixed along the upward-downward direction.
The above embodiment and modification examples are described using a case in which the hull attitude control apparatus 1 includes the shake detection sensor 19 or the positioning sensor 23 in order to detect the state (shake or movement) of the hull 2. The shake detection sensor 19 is described using an example in which a gyro sensor that detects an angular speed of the hull 2 is used as the shake detection sensor 19. A case is described in which the positioning sensor 23 is a sensor capable of detecting a self-position (positioning information including the latitude and the longitude) by a satellite positioning system (positioning satellite) such as a D-GPS, a GPS, a GLONASS, Hokuto, Galileo, or Michibiki. However, the embodiment is not limited thereto. The hull attitude control apparatus 1 may include a sensor capable of detecting or predicting the state of the hull 2. Examples of such a sensor include the following sensor.
As shown in
The distance sensor 24 detects a distance to a water surface W from a position at which the distance sensor 24 is attached. The distance detected by the distance sensor 24 is output as a signal to the outboard engine control portion 20 (refer to
The hull attitude control apparatus 1 may include a plurality of buoys 25 that float around the hull 2 and a buoy detection sensor 26 that detects the position and the height of each buoy 25 in order to detect the state of the hull 2. As a detection method of each buoy 25 by the buoy detection sensor 26, for example, a transmitter (not shown) may be provided on the buoy 25, and a receiver that receives a signal that is output from the buoy 25 may be provided on the buoy detection sensor 26. Further, as the buoy detection sensor 26, a camera that images the buoy 25 may be provided. The position and the height of each buoy 25 may be detected based on an image captured by the camera.
The position and the height of each buoy 25 detected by the buoy detection sensor 26 are output as a signal to the outboard engine control portion 20. The outboard engine control portion 20 obtains a shape of wave around the hull 2 on the basis of the position and the height of each buoy 25 and predicts the shake and the movement of the hull 2 on the basis of the shape of wave. The outboard engine control portion 20 performs an overall drive control of the motors 9, 10 and the hydraulic cylinder 17 on the basis of the predicted shake of the hull 2.
The hull attitude control apparatus 1 may include a small flight vehicle (drone) 27 in order to detect the state of the hull 2. The small flight vehicle 27 includes a sensor 27a that detects shaking and movement of the hull 2. As the sensor 27a, for example, a camera is used. Shaking and movement of the hull 2 detected by the small flight vehicle 27 is output as a signal to the outboard engine control portion 20. The outboard engine control portion 20 performs an overall drive control of the motors 9, 10 and the hydraulic cylinder 17 on the basis of the shake and the movement of the hull 2.
As shown in
The state of the wave R around the hull 2 imaged by the wave camera 28 is output as a signal to the outboard engine control portion 20. The outboard engine control portion 20 predicts the shake and the movement of the hull 2 on the basis of the state of the wave R and performs an overall drive control of the motors 9, 10 and the hydraulic cylinder 17.
When the object camera 29 is used, by using a horizontal line H or a surrounding object O as a reference, shaking and movement of the hull 2 is detected based on the change of the position of the horizontal line H or the object O. The outboard engine control portion 20 performs an overall drive control of the motors 9, 10 and the hydraulic cylinder 17 on the basis of shaking and movement of the hull 2 obtained from an image captured by the object camera 29. The object camera 29 may be the camera for detecting the buoy 25 described above. One camera may have a function of two cameras 28, 29 which are the wave camera 28 and the object camera 29.
The present invention is not limited to the embodiment described above and includes various modifications of the embodiment described above without departing from the scope of the present invention. For example, the embodiment and various modification examples described above may be used in combination.