Patent Publication Number: US-11034425-B2

Title: Ship control

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a national stage application pursuant to 35 U.S.C. § 371 of International Application No. PCT/JP2017/012117, filed on Mar. 24, 2017, which claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2016-062859, filed on Mar. 25, 2016, the disclosures of which are hereby incorporated by reference in their entireties. 
     TECHNICAL FIELD 
     The present invention relates to a ship, and particularly to a technique enabling a ship to be manipulated as if it was a vehicle. 
     BACKGROUND ART 
     Conventional ships have no concept of braking, and for example, a technique shown in Patent Literature 1 (PTL 1) adopts a method in which an accelerator lever is manipulated into a reverse traveling position to apply a propulsion force in a reverse direction or a method in which the accelerator lever is manipulated into a neutral position to make a propulsion force zero so that a ship decelerates or stops by inertia. In other words, in the conventional ships, the magnitude or the output direction of a propulsion force of a propulsion unit is changed by manipulating the accelerator lever, to limit a ship navigation speed. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent Application Laid-Open No. 2014-46864 
     SUMMARY OF INVENTION 
     Technical Problem 
     A ship steering operation is unique, and largely differs in many points from a method for manipulating a land vehicle. It therefore takes time for a beginner to be skilled in the ship steering operation. In view of these circumstances, an object of the present invention is to provide a technique enabling a ship to be manipulated as if it was a vehicle. 
     Solution to Problem 
     A ship according to an aspect of the present invention includes: a propulsion unit that exerts a propulsion force on a ship hull by power from an engine; detection means for detecting a current position, a bow direction, and a moving speed of the ship hull; a brake pedal that limits a moving speed of the ship hull; a brake sensor that detects a foot-pushing amount on the brake pedal; and a control device that is connected to the propulsion unit, the detection means, and the brake sensor, the control device being configured to acquire an operating status of the propulsion unit and detection results obtained by the detection means and the brake sensor, and to control the propulsion unit based on the detection results, the control device being configured to change an output of the propulsion unit in accordance with a foot-pushing amount on the brake pedal detected by the brake sensor. 
     The control device may perform a dynamic positioning control upon the brake sensor detecting manipulation on the brake pedal in a state where a moving speed of the ship hull detected by the detection means is zero. 
     Advantageous Effects of Invention 
     An aspect of the present invention can provide a technique enabling a ship to be manipulated as if it was a vehicle. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  A diagram showing a basic configuration of a ship. 
         FIG. 2  A diagram showing an engine and an out-drive unit. 
         FIG. 3  A block diagram of a ship steering control. 
         FIG. 4  A diagram showing a configuration of a shift lever. 
         FIG. 5  A flowchart of vehicle-like ship steering. 
         FIG. 6  A flowchart of vehicle-like ship steering. 
         FIG. 7  A flowchart of vehicle-like ship steering. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     A ship  100  will be described with reference to  FIG. 1  and  FIG. 2 . The ship  100  according to this embodiment is a so-called twin propeller ship. The number of propeller shafts is not limited to two, and the ship only needs to include a plurality of shafts. 
     The ship  100  includes a ship hull  1  including two engines  10  and two out-drive units  20 . The out-drive units  20  as propulsion units are driven by the engines  10 , and a propulsion force is exerted on the ship hull  1  by rotating propulsive propellers  25  of the out-drive units  20 . The ship hull  1  includes an accelerator pedal  2 , a steering  3 , a joystick lever  4 , a shift lever  41 , a brake pedal  42 , and the like, as manipulation tools for manipulating the ship  100 . In accordance with manipulation on these manipulation tools, operating statuses of the engines  10 , a propulsion force from the out-drive units  20 , and directions in which the propulsion force is exerted are controlled. 
     In this embodiment, the ship  100  is a stern drive ship including two engines  10  and two out-drive units  20 , but is not limited to such a type, and for example, may be a shaft ship including a plurality of propeller shafts, or a ship including a POD type propeller. 
     By manipulating the steering  3  or the joystick lever  4  of the ship hull  1 , output directions of the out-drive units  20  can be changed so that a course of the ship  100  can be changed. The ship hull  1  includes a ship steering control device  30  for performing a ship steering control on the ship  100 . 
     The ship hull  1  includes the steering  3 , the joystick lever  4 , the shift lever  5 , and the brake pedal  42  as manipulation means for controlling the out-drive units  20  for ship steering. The ship hull  1  also includes a global navigation satellite system (GNSS) device  5   a  and a heading sensor  5   b  as detection means  5  for detecting a current position, a bow direction, and a moving speed of the ship hull  1 . The GNSS device  5   a  detects the current position and the moving speed of the ship hull  1 . The heading sensor  5   b  detects the bow direction of the ship hull  1 . The GNSS device  5   a  acquires the current position of the ship hull  1  every predetermined time using a satellite positioning system to thereby detect the moving speed and the moving direction based on a positional shift in addition to the current position of the ship hull  1 . A turning speed is detected based on the amount of change in the bow direction detected by the heading sensor  5   b  per a unit time. The ship hull  1  also includes a monitor  6  disposed near the steering  3 , for example. The monitor  6  displays a manipulation status of the manipulation tools and a detection result obtained by the detection means  5 , and the like. 
     In this embodiment, the current position, the bow direction, the moving speed, and the like, of the ship hull  1  are detected by the detection means  5  including the GNSS device  5   a  and the heading sensor  5   b . This, however, is not limitative. For example, a GNSS device for detecting the current position of the ship hull, a gyro sensor for detecting the bow direction of the ship hull, and an electromagnetic log for detecting a sea speed of the ship hull, may be used for separate detections. Alternatively, all of the current position, the bow direction, the moving speed, and the like, may be detected by a GNSS device alone. 
     An ECU  15 , which controls the engine  10 , is provided in each of the engines  10 . The ECU  15  stores various programs and data for the control on the engine  10 . The ECU  15  may be configured with a CPU, a ROM, a RAM, an HDD, and the like, connected by a bus, or may be configured with a one-chip LSI, for example. 
     The ECU  15  is electrically connected to a fuel metering valve of a fuel supply pump, a fuel injection valve, and various sensors for detecting operating statuses of various devices in the engine  10 , though not shown. The ECU  15  controls a feed rate of the fuel metering valve and open/close of the fuel injection valve, and acquires information detected by the various sensors. 
     Each of the out-drive units  20  rotates a propulsive propeller  25 , to cause a propulsion force in the ship hull  1 . The out-drive unit  20  includes an input shaft  21 , a switching clutch  22 , a drive shaft  23 , an output shaft  24 , and the propulsive propeller  25 . In this embodiment, one out-drive unit  20  is cooperatively coupled to one engine  10 . Here, the number of out-drive units  20  provided for one engine  10  is not limited to the one described in this embodiment. A drive device is not limited to the out-drive unit  20  of this embodiment. A device whose propeller is directly or indirectly driven by the engine, or a POD type one may be adoptable, too. 
     The input shaft  21  transmits rotational power of the engine  10  to the switching clutch  22 . The input shaft  21  has one end portion thereof coupled to a universal joint attached to an output shaft  10   a  of the engine  10 , and the other end portion thereof coupled to the switching clutch  22  disposed inside an upper housing  20 U. 
     The switching clutch  22  is able to switch the rotational power of the engine  10 , which has been transmitted through the input shaft  21  and the like, from one to the other between a normal rotation direction and a reverse rotation direction. The switching clutch  22  includes a normal rotation bevel gear coupled to an inner drum having disk plates, and a reverse rotation bevel gear. The switching clutch  22  presses a pressure plate of an outer drum which is coupled to the input shaft  21  against any of the disk plates, to transmit power. The switching clutch  22  brings the pressure plate into a half-clutch state in which the pressure plate is imperfectly pressed against any of the disk plates, to thereby transmit part of the rotational power of the engine  10  to the propulsive propeller  25 . The switching clutch  22  brings the pressure plate into a neutral position where the pressure plate is not pressed against any of the disk plates, to thereby disable transmission of the rotational power of the engine  10  to the propulsive propeller  25 . 
     The drive shaft  23  transmits the rotational power of the engine  10 , which has been transmitted through the switching clutch  22  and the like, to the output shaft  24 . A bevel gear disposed at one end of the drive shaft  23  is meshed with the normal rotation bevel gear and the reverse rotation bevel gear of the switching clutch  22 , and a bevel gear disposed at the other end of the drive shaft  23  is meshed with a bevel gear of the output shaft  24  disposed inside a lower housing  20 R. 
     The output shaft  24  transmits the rotational power of the engine  10 , which has been transmitted through the drive shaft  23  and the like, to the propulsive propeller  25 . The bevel gear disposed at one end of the output shaft  24  is meshed with the bevel gear of the drive shaft  23  as mentioned above, and the other end of the output shaft  24  is provided with the propulsive propeller  25 . 
     Rotation of the propulsive propeller  25  generates a propulsion force. The propulsive propeller  25  is driven by the rotational power of the engine  10  which has been transmitted through the output shaft  24  and the like, and generates a propulsion force by paddling surrounding water with a plurality of blades  25   b  which are arranged around a rotation shaft  25   a.    
     Each of the out-drive units  20  is supported by a gimbal housing  1   a  which is attached to a quarter board (transom board) of the ship hull  1 . To be specific, each of the out-drive units  20  is supported by the gimbal housing  1   a  in such a manner that a gimbal ring  26  serving as a rotation fulcrum shaft is substantially perpendicular to a waterline w. 
     An upper portion of the gimbal ring  26  extends to the inside of the gimbal housing  1   a  (ship hull  1 ), and a steering arm  29  is attached to the upper end of the gimbal ring  26 . Rotation of the steering arm  29  causes rotation of the gimbal ring  26 , so that the out-drive unit  20  rotates about the gimbal ring  26 . The steering arm  29  is driven by a hydraulic actuator  27  that is actuated in conjunction with manipulation on the steering  3  or the joystick lever  4 . The hydraulic actuator  27  is controlled by an electromagnetic proportional control valve  28  that switches a flow direction of a working fluid in accordance with manipulation on the steering  3  or the joystick lever  4 . 
     A configuration for a ship steering control that is performed by a ship steering control device will be described with reference to  FIG. 3  to  FIG. 7 . As shown in  FIG. 3 , the ship steering control device  30  controls the engines  10  and the out-drive units  20  based on detection signals supplied from manipulation tools such as the accelerator pedal  2 , the steering  3 , the joystick lever  4 , the shift lever  41 , the brake pedal  42 , and the like. The ship steering control device  30  acquires information concerning the current position, the moving speed, the moving direction, the bow direction, and a turning amount of the ship hull  1  from the detection means  5  (the GNSS device  5   a  and the heading sensor  5   b ). Based on detection results obtained by the detection means  5  and manipulation on the manipulation tools, the ship steering control device  30  performs a ship steering control on the ship  100 . 
     The ship steering control device  30  stores various programs and data for controlling the engines  10  and the out-drive units  20 . The ship steering control device  30  may be configured with a CPU, a ROM, a RAM, an HDD, and the like, connected by a bus, or may be configured with a one-chip LSI, for example. 
     The ship steering control device  30 , which is connected to the accelerator pedal  2 , the steering  3 , the joystick lever  4 , the shift lever  41 , the brake pedal  42 , and the like, acquires detection signals that are generated by various sensors when these manipulation tools are manipulated. 
     More specifically, as shown in  FIG. 3 , the ship steering control device  30  is electrically connected to: an accelerator sensor  51  for detecting a foot-pushing amount which is a manipulation amount on the accelerator pedal  2 ; a steering sensor  52  for detecting a rotation angle which is a manipulation amount on the steering  3 ; a sensor for detecting a manipulation angle, a manipulation amount, and the like, of the joystick lever  4 ; a lever sensor  53  for detecting a manipulation position of the shift lever  41 ; and a brake sensor  54  for detecting a foot-pushing amount which is a manipulation amount on the brake pedal  42 . The ship steering control device  30  acquires, as manipulation amounts, detection values that are based on detection signals transmitted from these sensors. 
     The ship steering control device  30 , which is electrically connected to the ECUs  15  of the respective engines  10 , acquires various detection signals concerning operating statuses of the engines  10  acquired by the ECUs  15 . The ship steering control device  30  transmits, to the ECUs  15 , signals for turning on and off the engines  10  (ECUs  15 ) and control signals for controlling the fuel metering valves of the fuel supply pumps and other devices in the engines  10 . The ship steering control device  30 , which is electrically connected to the electromagnetic proportional control valves  28  of the respective out-drive units  20 , controls the electromagnetic proportional control valves  28  based on control signals supplied from the manipulation tools, for steerage. 
     A configuration of the shift lever  41  will now be described with reference to  FIG. 4 . As shown in  FIG. 4 , a lever guide  43  for guiding manipulation on the shift lever  41  is disposed around the shift lever  41 . In the lever guide  43 , forward traveling (S,  1 ,  2 ,  3 ), neutral (N), and reverse traveling (R) are arranged linearly, and positioning (P) is disposed on a lateral side of the neutral (N). The shift lever  41  can be held at each of the positions. The lever sensor  53  detects a shift position at which the shift lever  41  is held. In a range from the neutral (N) position to the forward traveling (S,  1 ,  2 ,  3 ) position and the reverse traveling (R) position, the shift lever  41  is manipulated in one direction along the lever guide  43 . In a range from the neutral (N) position to the positioning (P) position, the shift lever  41  is manipulated in a direction orthogonal to the one direction. 
     The manipulation position of the shift lever  41  of this embodiment includes seven positions in total, namely, the four forward traveling positions, the neutral position, the reverse traveling position, and the positioning position. For the forward traveling, multiple speed positions are provided, each of which is set corresponding to each speed range. Namely, the forward traveling (S) corresponds to trolling (very low speed), the forward traveling ( 1 ) corresponds to low speed, the forward traveling ( 2 ) corresponds to intermediate speed, and the forward traveling ( 3 ) corresponds to high speed. The positions of the shift lever  41  are not limited to the ones illustrated in this embodiment, as long as they include at least four positions of a forward traveling position, a neutral position, a reverse traveling position, and a positioning position. The shape of the lever guide  43  is not limited to the one illustrated in this embodiment. It however is preferable that a manipulation direction toward the positioning position is different from a manipulation direction from the neutral position toward the forward or reverse traveling position. 
     Manipulating the shift lever  41  into the positioning (P) position causes a dynamic positioning control to be performed. The dynamic positioning control is a control for holding a position of the ship  100  and an azimuth of the bow of the ship hull  1 . In the dynamic positioning control, the ECUs  15  of the engines  10  and the out-drive units  20  are controlled such that a propulsion force exerted by the two out-drive units  20  is balanced with an external force such as wind power and tidal power. 
     To be specific, the lever sensor  53  detects that the manipulation position of the shift lever  41  is at the positioning position. When such a detection result is acquired by the ship steering control device  30 , the ship steering control device  30  calculates a target moving amount, a target moving direction, and a target turning amount based on information acquired from the detection means  5 , the information concerning the current position, the moving speed, the moving direction, the bow direction, and the turning amount of the ship hull  1 . In accordance with a calculation result, the ship steering control device  30  controls an operating status of each engine  10 , an output of a propulsion force from each out-drive unit  20 , and a direction of the propulsion force. This dynamic positioning control performed by the ship steering control device  30  enables the ship  100  to be automatically held at a set position and a set azimuth. 
     In the shift lever  41 , a maximum number of revolutions of the engine  10  is set in accordance with its manipulation position. As a result, assignment of a foot-pushing amount on the accelerator pedal  2  and an output until reaching a maximum output is controlled such that a maximum output (a maximum moving speed of the ship hull  1 ) of the out-drive unit  20  can be equal to a maximum output that is set to be exerted when the accelerator pedal  2  is foot-pushed to the maximum. That is, a pseudo gear change is performed by manipulating the shift lever  41 , and a speed range that can be outputted by the out-drive unit  20  is set for each manipulation position. An actual output of the out-drive unit  20  (a navigation speed of the ship  100 ) within the speed range set by the shift lever  41  is operated by the accelerator pedal  2  which will be illustrated below. 
     The accelerator pedal  2  controls the number of revolutions of the two engines  10 . The ship hull  1  is provided with one accelerator pedal  2 . A foot-pushing amount on the accelerator pedal  2  is detected by the accelerator sensor  51 . The ship steering control device  30  transmits a control signal to the ECU  15  in accordance with the foot-pushing amount on the accelerator pedal  2  thus detected, to change the number of revolutions of the engine  10 . 
     That is, based on a manipulation position of the shift lever  41  and a foot-pushing amount (foot-pushing strength) on the accelerator pedal  2 , an output of the out-drive unit  20  is controlled, and a navigation speed of the ship  100  is determined. In a case where the shift lever  41  is manipulated into the low speed forward traveling (S) position so that a low-speed speed range of the forward traveling is set, a foot-pushing amount on the accelerator pedal  2  is assigned as a slip ratio (trolling ratio) in the half-clutch state of the switching clutch  22 . Thereby, delicate manipulation within the low-speed speed range is allowed. 
     As thus described above, in this embodiment, the shift lever  41  including at least four manipulation positions of the forward traveling position, the neutral position, the reverse traveling position, and the positioning position is provided, and the maximum output of the out-drive unit  20  is controlled in accordance with a manipulation position of the shift lever  41 . Thereby, the navigation speed of the ship  100  is suppressed. As a result, in the ship  100 , a pseudo shift change similar to that of a vehicle can be performed, in which the manipulation position of the shift lever  41  is changed so as to obtain a desired navigation speed of the ship  100 . Thus, a ship steering like a vehicle steering can be achieved. Manipulating the shift lever  41  into the positioning position causes the dynamic positioning control to be performed on the ship  100 . This provides a pseudo parking control similar to that of a vehicle. Thus, a ship steering (ship stopping manipulation) can be achieved. In addition, an output of the out-drive unit  20  within a speed range set by the shift lever  41  is controlled by manipulation on the accelerator pedal  2 . This corresponds rightly to a traveling control operation in a vehicle, and therefore a ship steering like a vehicle steering can be achieved. 
     To eliminate the need to check a speed every time inside a bay, it may be possible that the GNSS device  5   a  detects a current position and a navigation speed of the ship  100 , whether or not it is in a navigation speed restricted area is determined based on the current position of the ship  100 , and if it is in the restricted area, the navigation speed is limited so as not to exceed a set speed. This can automatically avoid exceeding the set speed even when the shift lever  41  is manipulated in a speed range including a speed that exceeds a limit speed. It may be also possible to make setting that increases a low-speed side torque by adjusting the assignment of an output of the out-drive unit  20  generated relative to a foot-pushing amount on the accelerator pedal  2  or by changing the output itself of the out-drive unit  20  such as changing a compatible value for controlling a fuel injection amount which is determined depending on an engine load and the number of revolutions of the engine. 
     The brake pedal  42  limits a moving speed of the ship hull  1  by controlling an output and a direction of the two out-drive units  20 . The ship hull  1  is provided with one brake pedal  42 . A foot-pushing amount on the brake pedal  42  is detected by the brake sensor  54 . In accordance with the foot-pushing amount on the brake pedal  42  thus detected, the ship steering control device  30  changes the number of revolutions of the engine  10 , an output of a propulsion force from the out-drive unit  20 , and a direction of the propulsion force. That is, by the foot-pushing amount (foot-pushing strength) on the brake pedal  42 , the magnitude and direction of the propulsion force from the out-drive unit  20  are controlled, and a navigation speed of the ship  100  is limited. 
     More specifically, a manipulation amount on the brake pedal  42  is detected by the brake sensor  53 , and based on its detection value, the ship steering control device  30  determines an output of a propulsion force from the out-drive unit  20  and a direction in which the propulsion force is exerted, to thereby determine the amount of deceleration of the ship hull  1 . 
     For example, when the brake pedal  42  is kept weakly foot-pushed, the output of the out-drive unit  20  is decreased without changing the output direction, or the output of the out-drive unit  20  is decreased and then the output direction is reversed, so that the ship  100  gradually decelerates, to stop the ship. When the brake pedal  42  is strongly foot-pushed, the output direction of the out-drive unit  20  is reversed so that the speed of the ship  100  rapidly drops, to stop the ship. When the brake pedal  42  is further strongly foot-pushed, an astern operation is performed in which the output direction of the out-drive unit  20  is reversed and the output is increased, to quickly stop the ship  100 . A quick stop of the ship can be handled by shortening delay processing which is executed for relieving a shock caused by the astern operation. By keeping the brake pedal  42  foot-pushed, the propulsion force of the out-drive unit  20  is controlled until the moving speed of the ship  100  finally reaches zero. The assignment of the foot-pushing amount on the brake pedal  42  and the propulsion force of the out-drive unit  20  is performed as appropriate. The strength of manipulation on the brake pedal  42  can be identified not only based on a foot-pushing amount on the brake pedal  42  but also based on both an output of the engine  10  and a foot-pushing amount on the brake pedal  42 . 
     When the brake pedal  42  is manipulated to limit the moving speed of the ship hull  1 , the GNSS device  5   a  detects the current position and the moving speed of the ship hull  1 . The ship steering control device  30 , therefore, is configured to perform the dynamic positioning control upon detecting that the brake pedal  42  has been manipulated with the moving speed of the ship hull  1  being zero. That is, if the brake pedal  42  is manipulated while the ship hull  1  is stopped, an output of a propulsion force from the out-drive unit  20  and a direction of the propulsion force are controlled such that the ship  100  stays on the current ship stop position and the current ship stop azimuth. 
     A specific manipulation on the brake pedal  42  is as follows. To decelerate the ship  100  during navigation, the brake pedal  42  is foot-pushed in accordance with a desired degree of deceleration. Then, to stop the ship, the brake pedal  42  is kept foot-pushed until the moving speed reaches zero. To stop the ship  100  at a predetermined position and hold the ship  100  at this position, firstly the brake pedal  42  is foot-pushed to decelerate the ship hull  1 , then the manipulation on the brake pedal  42  is continued until the moving speed reaches zero, and then the brake pedal  42  is further kept foot-pushed while the ship is stopped. Through this manipulation, the dynamic positioning control is performed, so that the ship  100  can be stopped and held at the predetermined position. 
     As described above, the moving speed of the ship hull  1  can be limited by manipulating the brake pedal  42  provided in the ship hull  1 , and further the dynamic positioning can be performed at the ship stop position by manipulating the brake pedal  42  while the ship is stopped. This corresponds rightly to a deceleration or stop operation in a vehicle. Thus, a ship steering like a vehicle steering can be achieved. 
     The steering  3  changes a direction of the out-drive unit  20 , to change a traveling direction of the ship hull  1 . A rotation angle which corresponds to a manipulation amount on the steering  3  is detected by the steering sensor  52 . Here, unlike a vehicle, the ship  100  has a unique operation called “pivot turn” in which only turning is performed by causing the out-drive units  20  to output in opposite directions. In this embodiment, the turn operating, which is so-called “pivot turn”, is performed by manipulating the steering  3 . 
     The ship steering control device  30  permits or prohibits the turning-alone operation with the steering  3 , in accordance with a moving speed of the ship hull  1  (a navigation speed of the ship  100 ) detected by the detection means  5 . If the navigation speed of the ship  100  is equal to or less than a predetermined value and the rotation angle detected by the steering sensor  52  is more than a predetermined threshold value (e.g., 360 degrees), the out-drive units  20 ,  20  are caused to output in opposite directions, to perform turning toward a direction in which the steering  3  is manipulated. 
     As shown in  FIG. 3 , announcing means  60  is electrically connected to the ship steering control device  30 . The announcing means  60  is provided near the steering  3 . The announcing means  60  announces to an operator that turning alone will be performed, by using sound, light, or the like. The announcement is made when the ship steering control device  30  performs a turning operation. 
     In this manner, the “pivot turn” for turning at the present place is performed only by manipulating the steering  3 . Thereby, a ship steering operation like a vehicle steering operation can be achieved, and in addition, operator convenience can be improved. It is conceivable to provide a limit on the navigation speed of the ship  100  as a condition for performing the “pivot turn”. This can avoid sudden turning. Since the announcing means  60  makes announcement at a time of performing the “pivot turn”, a ship steerability is given to the operator. 
     As means for achieving ship steering that is more similar to vehicle steering, the following is adoptable. A navigation path through which the ship  100  will navigate is predicted based on a manipulation amount on the steering  3  and a navigation speed of the ship  100 . If the distance between a current position of the ship  100  and the predicted navigation path is equal to or more than a certain fixed value, an output of the out-drive unit  20  is calibrated such that the current position of the ship  100  can be along the predicted navigation path. Such calibration makes a steering control less likely to be influenced by tide or wave. Thus, a ship steering that is more similar to a vehicle steering can be achieved. 
     In another possible control, the “pivot turn” may be performed by manipulating the joystick lever  4 . In a case of using the joystick lever  4  for the ship steering, the ship steering operation with the steering  3  is unavailable. 
     As shown in  FIG. 3 , a left switch  70  and a right switch  71  for causing lateral movement of the ship hull  1  are connected to the ship steering control device  30 . How these lateral movement switches  70 ,  71  are arranged is not limited. It is preferable that, for example, the lateral movement switches  70 ,  71  are arranged at a position that is highly convenient for performing lateral movement manipulation, such as a central portion (hub portion) of the steering  3 , the monitor  6 , or the like. Here, unlike a vehicle, the ship  100  has a unique operation in which, while the out-drive units  20  are caused to output in opposite directions, their outputs are adjusted to direct a synthetic vector resulting from their propulsion forces toward the port side or the starboard side, to thereby cause lateral movement of the ship hull  1 . In this embodiment, the lateral movement is performed by operating the lateral movement switches  70 ,  71 . 
     In another possible control, the “lateral movement” may be performed by manipulating the joystick lever  4 . In a case of using the joystick lever  4  for the ship steering, the ship steering operation with the lateral movement switches  70 ,  71  is unavailable. 
     As shown in  FIG. 3 , a vehicle-like ship steering switch  45  for starting/stopping a ship steering operation control enabling the ship  100  to be manipulated as if it was a vehicle is connected to the ship steering control device  30 . The vehicle-like ship steering switch  45  is arranged near the steering  3 , for example. When the vehicle-like ship steering switch  45  is ON, a vehicle-like ship steering control as described above is performed by the ship steering control device  30 . When the vehicle-like ship steering switch  45  is OFF, a normal ship steering control is performed by the ship steering control device  30 . The normal ship steering control is a conventional ship steering control, and means that the above-mentioned “pivot turn” with the steering  3  and the ship steering control with the shift lever  41 , the accelerator pedal  2 , and the brake pedal  42  are partially or entirely unavailable. 
     Control flows of the vehicle-like ship steering operation in a state where the vehicle-like ship steering switch  45  is ON will now be described with reference to  FIG. 5  to  FIG. 7 . 
       FIG. 5  shows a control step S 10  regarding manipulation on the shift lever and on the accelerator pedal. Firstly in step S 11 , the fact that the vehicle-like ship steering switch  45  is ON is acquired. In step S 12 , a ship steering state (information concerning a current position, a moving speed, a moving direction, a bow direction, and a turning amount detected by the detection means) is acquired. In step S 13 , a manipulation state (information concerning manipulation amounts on the manipulation tools detected by the various sensors) is acquired. 
     Then, in step S 14 , whether or not a shift position of the shift lever  41  detected by the lever sensor  53  is the positioning (P) position is determined. If the shift position is P (S 14 :Y), then in step S 15 , the dynamic positioning control is performed. If the shift position is not P (S 14 :N), then in step S 16 , a speed range and an output direction corresponding to the shift position are set, and then in step S 17 , the number of revolutions of the engine corresponding to an accelerator position of the accelerator pedal  2  detected by the accelerator sensor  51  is set. 
       FIG. 6  shows a control step S 20  regarding manipulation on the brake pedal. Firstly in step S 21 , the fact that the vehicle-like ship steering switch  45  is ON is acquired. In step S 22 , a ship steering state (information concerning a current position, a moving speed, a moving direction, a bow direction, and a turning amount detected by the detection means  5 ) is acquired. In step S 23 , a manipulation state (information concerning manipulation amounts on the manipulation tools detected by the various sensors) is acquired. 
     Then, in step S 24 , whether or not a moving speed of the ship hull  1  detected by the detection means  5  is zero is determined. If the moving speed is zero (S 24 :Y), then in step S 25 , the dynamic positioning control is performed. If the moving speed is not zero (S 24 :N), then in step S 26 , an output and a direction of a propulsion force from the out-drive unit  20  is changed in accordance with a pedal position of the brake pedal  42  detected by the brake sensor  54 . 
       FIG. 7  shows a control step S 30  regarding manipulation on the steering. Firstly, in step S 31 , the fact that the vehicle-like ship steering switch  45  is ON is acquired. In step S 32 , a ship steering state (information concerning a current position, a moving speed, a moving direction, a bow direction, and a turning amount detected by the detection means  5 ) is acquired. In step S 33 , a manipulation state (information concerning manipulation amounts on the manipulation tools detected by the various sensors) is acquired. 
     Then, in step S 34 , whether or not a moving speed of the ship hull  1  detected by the detection means  5  is equal to or less than a predetermined value is determined. If the moving speed is equal to or less than the predetermined value (S 34 :Y), then in step S 35 , whether or not a steering angle of the steering  3  detected by the steering sensor  52  is more than a threshold value is determined. If the steering angle is more than the threshold value (S 35 :Y), then in step S 36 , the pivot turn is performed. If the moving speed is more than the predetermined value (S 34 :N) or if the steering angle is equal to or less than the threshold value (S 35 :N), the processing advances to step S 37  to continue the normal ship steering control. 
     INDUSTRIAL APPLICABILITY 
     Some aspects of the present invention are applicable to ships. 
     REFERENCE SIGNS LIST 
       1 : ship hull,  2 : accelerator pedal,  3 : steering,  5 : detection means,  5   a : GNSS device,  5   b : heading sensor,  10 : engine,  20 : out-drive unit,  30 : ship steering control device,  41 : shift lever,  42 : brake pedal,  45 : vehicle-like ship steering switch,  51 : accelerator sensor,  52 : steering sensor,  53 : lever sensor,  54 : brake sensor