Vessel propulsion system and control method for the same

Abstract

To prevent autorotation during traverse movement of a vessel and at the same tima maintain navigation performance.SOLUTION: A chevron shape is formed by an outboard engine 14 on starboard side and an outboard engine 15 on port side in plan view by steering the outboard engine 14 on starboard side in a right turn direction as well as steering the outboard engine 15 on port side in a left turn direction when a vessel 10 is moved in a right lateral direction, furthermore, propulsion force FT in the same direction as lateral force F is generated in a trolling motor 16 by generating propulsion force fl backward in the outboard engine 14 on port side as well as by generating propulsion force fr forward in the outboard engine 15 on starboard side so as to position an action point P of traverse force F, which is resultant force of the propulsion force fl to backward and the propulsion force fr forward, behind a turning center of gravity G.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a ship propulsion system that enables lateral movement of a ship, and a control method thereof. [Background technology]

[0002] In a vessel equipped with multiple outboard motors at the stern, for example two outboard motors, when moving the hull laterally, the port-side outboard motor is steered in the port direction and the starboard-side outboard motor is steered in the starboard direction, causing the port-side outboard motor to generate a forward or rearward thrust and the starboard-side outboard motor to generate a thrust in the opposite direction to the thrust generated by the port-side outboard motor. At this time, the resultant force of the thrust generated by the starboard-side outboard motor and the thrust generated by the port-side outboard motor acts on the hull as a lateral movement force.

[0003] In a wide vessel such as a catamaran, multiple outboard motors are often mounted at a distance from each other at the stern, and in this case, even if the port and starboard outboard motors are steered to their maximum extent, the point of action of the resultant force may be in front of the center of gravity of the vessel for turning. As a result, a yaw moment is generated around the center of gravity of the vessel for turning due to the resultant force, and the vessel rotates in the yaw direction while moving laterally.

[0004] In view of this, a technique is known in which the mounting angle of each outboard motor relative to the hull is changed to move the point of application of the resultant force when one outboard motor and the other outboard motor are steered, thereby aligning the point of application of the resultant force with the center of gravity of the hull at the time of turning (see, for example, Patent Document 1). With this technique, since no yaw moment is generated around the center of gravity at the time of turning due to the resultant force, it is possible to prevent the boat from rotating in the yaw direction during lateral movement. In this technique, as shown in FIG. 12, in order to change the mounting angle of each outboard motor 122, 123 relative to the hull 120, each outboard motor 122, 123 is mounted to the hull 120 via wedge plates 124, 125 for adjusting the mounting angle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 10202179 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the outboard motors 122, 123 are attached to the hull 120 via the wedge plates 124, 125, the angle at which the outboard motors 122, 123 can be steered in the direction opposite to the direction in which the outboard motors are tilted by the wedge plates 124, 125 is reduced, affecting the turning performance of the boat. Also, when the outboard motors 122, 123 are in a neutral state with respect to steering, the rear of each outboard motor 122, 123 may protrude from the outside of the hull 120, which may result in increased resistance during navigation. Therefore, there is still room for improvement in preventing rotation during lateral movement while maintaining navigation performance.

[0007] An object of the present invention is to prevent rotation of a ship during lateral movement while maintaining its navigational performance. [Means for solving the problem]

[0008] A vessel propulsion system according to one aspect of the present invention includes a plurality of first propulsion units disposed at the stern of a hull and a second propulsion unit disposed on a bow side of the hull, and when the hull is moved laterally, the port-side first propulsion unit located on the port side of the center line in the fore-and-aft direction of the hull is steered maximally in the port turning direction, and the starboard-side first propulsion unit located on the starboard side of the center line is steered maximally in the right turning direction, so that, in a plan view, the port-side first propulsion unit and the starboard-side first propulsion unit form a V-shape, and a ship propulsion system in which, when the first propulsion unit on the port side is caused to generate a forward or rearward thrust and the first propulsion unit on the starboard side is caused to generate a thrust in the opposite direction to the thrust generated by the first propulsion unit on the port side, the point of application of a lateral force, which is the resultant force of the thrust generated by the first propulsion unit on the port side and the thrust generated by the first propulsion unit on the starboard side, is located forward of the center of gravity of the hull for turning, and a counter yaw moment is generated by another thrust generated by the second propulsion unit to counter the yaw moment around the center of gravity of the turning due to the lateral force.

[0009] According to this configuration, even if the point of application of the lateral movement force, which is the resultant force of the thrust generated by the first propulsion unit on the port side and the thrust generated by the first propulsion unit on the starboard side, is located forward of the center of gravity of the hull for turning, another thrust generated by the second propulsion unit generates a counter yaw moment that cancels the yaw moment around the center of gravity of the hull for turning due to the lateral movement force. This eliminates the need to change the mounting angle of the first propulsion units on both sides relative to the hull to make the point of application of the resultant force coincide with the center of gravity of the hull for turning. In other words, it is possible to eliminate the need to use a wedge plate to mount the first propulsion units on both sides to the hull. As a result, it is possible to prevent the ship from rotating during lateral movement without causing a decrease in navigation performance. In other words, it is possible to prevent the ship from rotating during lateral movement while maintaining navigation performance. Effect of the Invention

[0010] According to the present invention, it is possible to prevent rotation of the ship while it is moving laterally and to maintain its navigational performance. [Brief description of the drawings]

[0011] [Figure 1] 1 is a plan view of a boat to which a boat propulsion system according to a first embodiment of the present invention is applied. [Diagram 2] 1 is a side view of a vessel to which a vessel propulsion system according to a present embodiment is applied. [Diagram 3] 1 is a block diagram for illustrating a schematic configuration of a marine vessel propulsion system according to a present embodiment. [Figure 4] 11A and 11B are diagrams for explaining problems that arise when moving laterally in the present embodiment. [Diagram 5] 13 is a diagram for explaining a form at the time of movement in a right lateral direction in the present embodiment. FIG. [Figure 6] 13 is a diagram for explaining a form at the time of movement in a left lateral direction in the present embodiment. FIG. [Figure 7] FIG. 2 is a plan view showing a state in which the distance from the center of gravity for turning to the propeller is increased in this embodiment. [Figure 8] FIG. 4 is a diagram for explaining a configuration for increasing the distance from the center of gravity for turning to the propeller in the present embodiment. [Figure 9] FIG. 13 is a diagram for explaining a form when moving laterally to the right in the second embodiment of the present invention. [Figure 10] 13 is a diagram for explaining a form at the time of movement in a left lateral direction in the present embodiment. FIG. [Figure 11] FIG. 2 is a plan view showing a state in which the distance from the center of gravity for turning to the propeller is increased in this embodiment. [Figure 12] FIG. 1 is a diagram for explaining lateral movement of a vessel using a conventional vessel propulsion system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described.

[0013] FIG. 1 is a plan view of a ship to which a ship propulsion system according to a first embodiment of the present invention is applied, and FIG. 2 is a side view of the ship to which the ship propulsion system according to the present embodiment is applied.

[0014] 1 and 2, the boat 10 is a twin-hull pontoon boat having a slender hull 11 located on the port side of a centerline CL in the fore-and-aft direction, and a slender hull 12 located on the starboard side of the centerline CL. In addition, the boat 10 has outboard motors 14, 15 (first propulsion units) attached to the sterns of the left and right hulls 11, 12, respectively. The outboard motors 14, 15 can be steered to turn right or left relative to the corresponding hulls 11, 12, respectively.

[0015] In this embodiment, steering in the right turning direction refers to a state in which the outboard motors 14, 15 rotate counterclockwise around the stern of the hulls 11, 12 as a fulcrum in a plan view of the boat 10. Steering in the left turning direction refers to a state in which the outboard motors 14, 15 rotate clockwise around the stern of the hulls 11, 12 as a fulcrum in a plan view of the boat 10. In addition, in the boat 10, the outboard motors 14, 15 are configured to be able to steer by, for example, 30° in each of the right turning direction and the left turning direction.

[0016] A pontoon boat has a configuration in which a deck 13 spans between left and right hulls 11, 12, for example, and is therefore wider than a normal monohull. Therefore, the pitch at which the outboard motors 14, 15 are arranged is also larger than that of a normal monohull. In addition, a pontoon boat prioritizes stability over speed performance, and is suitable for use in relatively slow cruising and fishing while anchored on the water. Therefore, in addition to the outboard motors 14, 15, the boat is equipped with a small outboard motor for navigating at low speeds and adjusting position when anchored. For example, the boat 10 is equipped with a trolling motor 16 (second propulsion unit) arranged on the bow side.

[0017] The trolling motor 16 has a spindle-shaped submerged body 17 that houses an electric motor that drives a propeller 17a, and the direction of the submerged body 17 can be freely changed by rotating a rod 18, to the tip of which the submerged body 17 is attached, around an axis by the operator or a rotating unit (not shown). This allows the trolling motor 16 to change the direction of the thrust generated by the propeller 17a to a desired direction, and the trolling motor 16 can be used to change the course of the ship 10 when traveling at low speed or to adjust the position when anchored. The trolling motor 16 is usually disposed on the center line CL, but can be relocated and can also be disposed on the bow of the hull 11 or hull 12 as shown in the figure. When the ship 10 travels at a relatively high speed, the trolling motor 16 is raised to the deck 13 or the hulls 11 and 12 so as not to become a resistance.

[0018] Fig. 3 is a block diagram for explaining a schematic configuration of a vessel propulsion system mounted on the vessel 10 of Fig. 1. In Fig. 3, the vessel propulsion system 19 includes a Boat Control Unit (BCU) 20, a Multi Function Display (MFD) 21, a Global Navigation Satellite System (GNSS), such as a Global Positioning System (GPS) 22, an Inertial Measurement Unit (IMU) 23, a compass 24, a remote control unit 25, a joystick 26, a steering mechanism 27, a maneuvering panel 28, a remote control ECU 29, a main operation unit 30, and a Steering Control Unit (SCU) 31. The components of the vessel propulsion system 19 are connected to each other so as to be able to communicate with each other.

[0019] The GPS 22 determines the current position of the ship 10 and transmits the current position of the ship 10 to the BCU 20. The IMU 23 measures the behavior of the hulls 11 and 12 and transmits the measurement results to the BCU 20. The compass 24 determines the direction of the ship 10 and transmits the direction of the ship 10 to the BCU 20.

[0020] The remote control unit 25 has levers 25a corresponding to the outboard motors 14, 15, and the boat helmsman operates each lever 25a to switch the direction of thrust generated by the corresponding outboard motor 14, 15 between forward and backward, and adjusts the magnitude of the output of the corresponding outboard motor 14, 15 to adjust the boat speed. At this time, the remote control unit 25 transmits signals for controlling the outboard motors 14, 15 to the BCU 20 and the remote control ECU 29 in response to the operation of the levers 25a. The joystick 26 is a control stick for steering the boat 10, and transmits signals for moving the boat 10 in the tilting direction to the BCU 20 and the remote control ECU 29. The steering mechanism 27 is a device for the boat helmsman to determine the course of the boat 10, and the boat helmsman can turn the boat 10 left or right by rotating a steering wheel 27a of the steering mechanism 27 left or right. At this time, the steering mechanism 27 transmits a rudder angle corresponding to the rotation of the steering wheel 27a to the remote control ECU 29 and the SCU 31.

[0021] The main operation unit 30 has a main switch 30a and an engine shutoff switch 30b. The main switch 30a is an operator for collectively starting and stopping the engines (not shown) that are the power sources of the outboard motors 14, 15, and the engine shutoff switch 30b is a switch for emergency stopping the engines of the outboard motors 14, 15. The MFD 21 is, for example, a color LCD display, and functions as a display for displaying various information and also as a touch panel for receiving inputs from the operator. The steering panel 28 has switches (not shown) corresponding to various steering modes, and the operator operates the corresponding switch to switch the boat 10 into a desired steering mode, for example, a fixed-point mode.

[0022] The SCU 31 is provided corresponding to each of the outboard motors 14, 15, and controls a steering unit (not shown) that turns the corresponding outboard motor 14, 15 relative to the hulls 11, 12 to change the direction of thrust of each outboard motor 14, 15.

[0023] The BCU 20 grasps the status of the boat 10 based on signals transmitted from each component of the boat propulsion system 19, determines the magnitude and direction of thrust that each outboard motor 14, 15 should generate, and transmits the determined magnitude and direction of thrust to each remote control ECU 29. The BCU 20 also controls the rotation unit of the trolling motor 16 to change the magnitude and direction of thrust of the trolling motor 16.

[0024] The remote control ECU 29 is provided for each of the outboard motors 14, 15, and transmits signals to the engine ECU (not shown) and SCU 31 of each outboard motor 14, 15 to control the engine and steering unit of each outboard motor 14, 15 in response to signals transmitted from the BCU 20, the steering mechanism 27, the remote control unit 25, the joystick 26, etc., thereby adjusting the magnitude and direction of thrust of the outboard motors 14, 15.

[0025] FIG. 4 is a diagram for explaining the problem of moving the boat 10 in the lateral direction. For example, when moving the boat 10 in the right lateral direction (the direction of the white arrow in the figure), the boat operator operates the joystick 26 and the steering mechanism 27 to input a command for the right lateral direction. At this time, the SCU 31 steers the port-side outboard motor 14 in the port direction and steers the starboard-side outboard motor 15 in the starboard direction, so that the port-side outboard motor 14 and the starboard-side outboard motor 15 form a V-shape in a plan view. Then, the remote control ECU 29 causes the port-side outboard motor 14 to generate a forward thrust fl and causes the starboard-side outboard motor 15 to generate a rearward thrust fr. Note that the magnitude of the forward thrust fl and the rearward thrust fr are the same. As a result, the resultant force of the forward thrust fl and the rearward thrust fr acts on the boat 10 as a lateral movement force F in the right lateral direction.

[0026] As described above, since the boat 10 is a pontoon boat, the pitch of the outboard motors 14, 15 is larger than that of a normal monohull boat. Therefore, even if the port-side outboard motor 14 is steered to the maximum extent in the port direction and the starboard-side outboard motor 15 is steered to the maximum extent in the starboard direction, the application point P of the lateral force F remains forward of the hull's center of gravity G for turning. At this time, a clockwise yaw moment M about the center of gravity G for turning is generated by the lateral force F, and as the boat 10 moves laterally to the right, it rotates in the yaw direction about the center of gravity G for turning.

[0027] In this embodiment, when the vessel 10 moves laterally to the right, in order to suppress rotation in the yaw direction around the turning center of gravity G, the thrust of the trolling motor 16 is used to generate a counter yaw moment MC that counters the yaw moment M generated by the lateral movement force F.

[0028] 5 is a diagram for explaining a mode of movement in a right lateral direction in this embodiment. In this embodiment, when moving the boat 10 in a right lateral direction (in the direction of the outlined arrow in the figure), the SCU 31 steers the port-side outboard motor 14 in a right turning direction and steers the starboard-side outboard motor 15 in a left turning direction, so that the port-side outboard motor 14 and the starboard-side outboard motor 15 form an inverted V shape in a plan view.

[0029] In the boat 10, when the port-side outboard motor 14 is steered to the maximum extent in the right direction and the starboard-side outboard motor 15 is steered to the maximum extent in the right direction, the port-side outboard motor 14 and the starboard-side outboard motor 15 approach each other. However, in the boat 10, the pitch of the outboard motors 14, 15 is set large enough that the port-side outboard motor 14 and the starboard-side outboard motor 15 do not interfere with each other.

[0030] The remote control ECU 29 then causes the port-side outboard motor 14 to generate a rearward thrust fl, and causes the starboard-side outboard motor 15 to generate a forward thrust fr. The magnitude of the rearward thrust fl and the forward thrust fr are equal. As a result, the resultant force of the rearward thrust fl and the forward thrust fr acts on the boat 10 as a lateral movement force F in the right lateral direction.

[0031] At this time, as shown in the figure, the rearward thrust fl of the port-side outboard motor 14 and the forward thrust fr of the starboard-side outboard motor 15 intersect behind the turning center of gravity G, so the point of application P of the lateral force F is also located behind the turning center of gravity G. In other words, because the point of application P of the lateral force F does not coincide with the turning center of gravity G, a counterclockwise yaw moment M is generated around the turning center of gravity G by the lateral force F.

[0032] Meanwhile, the BCU 20 rotates the rod 18 of the trolling motor 16 about its axis, causing the trolling motor 16 to generate a thrust force FT (another thrust force) in the right lateral direction. At this time, the thrust force FT generates a counter yaw moment MC about the turning center of gravity G. And, because the trolling motor 16 is disposed on the bow side, the counter yaw moment MC is a clockwise yaw moment. Therefore, the counter yaw moment MC can cancel out the yaw moment M generated by the lateral movement force F in the right lateral direction.

[0033] The magnitude of the thrust force FT generated by the trolling motor 16 is determined in consideration of the magnitude of the yaw moment M and the distance from the turning center of gravity G to the trolling motor 16. Specifically, it is determined by the following formula (1). Thrust FT = Yaw moment M / Distance from center of gravity G to trolling motor 16 …(1)

[0034] In the following drawings, the yaw moment M and the counter yaw moment MC are drawn offset from the turning center of gravity G for ease of viewing. However, as described above, the yaw moment M and the counter yaw moment MC are both moments around the turning center of gravity G.

[0035] 6 is a diagram for explaining a configuration during left lateral movement in this embodiment. When the boat 10 is moved to the left lateral direction, the SCU 31 forms an inverted V shape with the port-side outboard motor 14 and the starboard-side outboard motor 15 in a plan view, similar to the case when the boat 10 is moved to the right lateral direction.

[0036] The remote control ECU 29 then causes the port-side outboard motor 14 to generate a forward thrust fl, and causes the starboard-side outboard motor 15 to generate a rearward thrust fr. The forward thrust fl and the rearward thrust fr have the same magnitude. As a result, the resultant force of the forward thrust fl and the rearward thrust fr acts on the boat 10 as a lateral movement force F in the left lateral direction.

[0037] At this time, as in the case of moving the boat 10 laterally to the right, the forward thrust fl of the port-side outboard motor 14 and the rearward thrust fr of the starboard-side outboard motor 15 intersect behind the turning center of gravity G, so the point of application P of the lateral movement force F is also located behind the turning center of gravity G. Then, a clockwise yaw moment M about the turning center of gravity G is generated by the lateral movement force F, whose point of application P is located behind the turning center of gravity G.

[0038] On the other hand, the BCU 20 causes the trolling motor 16 to generate a thrust force FT in the left lateral direction, and the thrust force FT generates a counter yaw moment MC in the counterclockwise direction around the turning center of gravity G. This counter yaw moment MC can cancel out the yaw moment M generated by the lateral movement force F in the left lateral direction. Note that even when the boat 10 is moved in the left lateral direction, the magnitude of the thrust force FT generated by the trolling motor 16 is determined by the above formula (1).

[0039] According to this embodiment, when the boat 10 is moved laterally, the port-side outboard motor 14 and the starboard-side outboard motor 15 form an inverted V shape in a plan view. Then, the port-side outboard motor 14 and the starboard-side outboard motor 15 generate thrust forces fl and fr in opposite directions to each other, generating a lateral movement force F whose point of application P is located rearward of the center of gravity G for turning. Furthermore, a thrust force FT in the same direction as the lateral movement force F is generated in the bow-side trolling motor 16. As a result, the yaw moment M generated by the lateral movement force F can be countered by the counter yaw moment MC generated by the thrust force FT.

[0040] As a result, there is no need to change the mounting angles of the port-side outboard motor 14 and the starboard-side outboard motor 15 with respect to the hulls 11, 12 to make the point of application of the resultant force of thrusts fl and fr coincide with the center of gravity G for turning. In other words, there is no need to use wedge plates to mount the port-side outboard motor 14 and the starboard-side outboard motor 15 to the hulls 11, 12. This makes it possible to prevent the boat 10 from rotating in the yaw direction during lateral movement without deteriorating the navigational performance of the boat 10. In other words, it is possible to prevent the boat 10 from rotating in the yaw direction while it is moving laterally and maintain its navigational performance at the same time.

[0041] In this embodiment, the direction of action of the lateral movement force F, which is the resultant force of the thrust fl of the port-side outboard motor 14 and the thrust fr of the starboard-side outboard motor 15, is the same as the direction of action of the thrust force FT generated in the trolling motor 16. Therefore, since not only the lateral movement force F but also the thrust force FT contributes to the lateral movement of the boat 10, the efficiency of the lateral movement of the boat 10 can be improved.

[0042] Furthermore, in this embodiment, the trolling motor 16 is used as a source of thrust FT that generates the counter yaw moment MC, but if the vessel 10 is equipped with a bow thruster or a side thruster on the bow side, the thrust FT may be generated by the bow thruster or the side thruster.

[0043] In this embodiment, the thrust fl of the port-side outboard motor 14 and the thrust fr of the starboard-side outboard motor 15 intersect significantly behind the turning center of gravity G, so the arm of the yaw moment M becomes longer, and the yaw moment M becomes larger. To counteract this large yaw moment M, it is necessary to increase the thrust FT generated by the trolling motor 16 to balance the counter yaw moment MC with the yaw moment M.

[0044] However, since the trolling motor 16 is configured to be relocatable, it is a relatively small propulsion unit, and the electric motor provided therewith is also relatively small, so there is a limit to the magnitude of thrust FT that can be generated. Furthermore, if the thrust FT is increased, the power consumption deteriorates, and in some cases, the charge level of the battery (not shown) provided in the boat 10 may become zero during lateral movement. Therefore, it is preferable that the thrust FT generated by the trolling motor 16 is small.

[0045] Therefore, in order to reduce the thrust force FT while maintaining the magnitude of the counter yaw moment MC, it is preferable to increase the distance from the turning center of gravity G, which is the arm length of the counter yaw moment MC, to the propeller 17a that generates the thrust force FT, as shown in Figure 7. Specifically, the thrust force FT is generated forward of the bow of the hull 11 (12).

[0046] FIG. 8 is a diagram for explaining a configuration for increasing the distance from the turning center of gravity G to the propeller 17a.

[0047] For example, as shown in Fig. 8(A), the trolling motor 16 may be equipped with an arm 32 that can be extended forward, and the rod 18 may be attached near the front end of the arm 32. In this case, as shown in Fig. 8(B), the arm 32 extends by sliding forward relative to the hull 11 (12), and the submerged body 17 having the propeller 17a is positioned forward of the bow. This increases the distance from the turning center of gravity G to the propeller 17a, and a counter yaw moment MC that cancels the yaw moment M can be generated even with a small thrust FT.

[0048] Also, for example, as shown in Fig. 8(C), the trolling motor 16 may be provided with a tiltable case 33, and the rod 18 may be housed in the case 33 so as to be extendable. In this case, as shown in Fig. 8(D), the case 33 is tilted so that the lower part of the case 33 moves forward, and further, the rod 18 is extended from the case 33. At this time, the rod 18 is inclined with respect to the water surface, but the submerged body 17 attached to the tip of the rod 18 is submerged forward of the bow. This also makes it possible to increase the distance from the turning center of gravity G to the propeller 17a of the submerged body 17.

[0049] In FIG. 8, the submerged body 17 faces forward, but when the vessel 10 moves laterally, the submerged body 17 faces in the direction of movement (lateral direction).

[0050] Next, a second embodiment of the present invention will be described. Since the second embodiment is basically the same as the first embodiment in terms of configuration and operation, the description of the overlapping configuration and operation will be omitted, and the following will describe the different configuration and operation.

[0051] In the first embodiment described above, a method for suppressing rotation in the yaw direction about the center of gravity G of turning using the thrust FT of the trolling motor 16 when the port side outboard motor 14 and the starboard side outboard motor 15 form an inverted V shape has been described. In contrast, in the second embodiment, a method for suppressing rotation in the yaw direction about the center of gravity G of turning using the thrust FT of the trolling motor 16 when the port side outboard motor 14 and the starboard side outboard motor 15 form an inverted V shape will be described.

[0052] 9 is a diagram for explaining a mode of movement in a right lateral direction in this embodiment. In this embodiment, when moving the boat 10 in a right lateral direction (in the direction of the outlined arrow in the figure), the SCU 31 steers the port-side outboard motor 14 in a port direction and steers the starboard-side outboard motor 15 in a right direction, so that the port-side outboard motor 14 and the starboard-side outboard motor 15 form a V shape in a plan view.

[0053] The remote control ECU 29 then causes the port-side outboard motor 14 to generate a forward thrust fl, and causes the starboard-side outboard motor 15 to generate a rearward thrust fr. The forward thrust fl and the rearward thrust fr have the same magnitude. As a result, the resultant force of the forward thrust fl and the rearward thrust fr acts on the boat 10 as a lateral movement force F in the right lateral direction.

[0054] At this time, as shown in the figure, the forward thrust fl of the port-side outboard motor 14 and the rearward thrust fr of the starboard-side outboard motor 15 intersect in front of the turning center of gravity G, so the point of application P of the lateral force F is also located in front of the turning center of gravity G. In other words, because the point of application P of the lateral force F does not coincide with the turning center of gravity G, a clockwise yaw moment M is generated around the turning center of gravity G by the lateral force F.

[0055] Meanwhile, the BCU 20 rotates the rod 18 of the trolling motor 16 about its axis, causing the trolling motor 16 to generate a thrust force FT in the left lateral direction, which is the opposite direction to the lateral movement force F. This thrust force FT in the left lateral direction generates a counter yaw moment MC, which is a yaw moment in the counterclockwise direction about the turning center of gravity G. Therefore, the counter yaw moment MC can cancel out the yaw moment M generated by the lateral movement force F in the right lateral direction. Note that, in this embodiment as well, the magnitude of the thrust force FT generated by the trolling motor 16 is determined by the above formula (1).

[0056] 10 is a diagram for explaining a form during movement laterally to the left in this embodiment. When the boat 10 is moved laterally to the left, the SCU 31 also forms a V shape with the port-side outboard motor 14 and the starboard-side outboard motor 15.

[0057] The remote control ECU 29 then causes the port-side outboard motor 14 to generate a rearward thrust fl, and causes the starboard-side outboard motor 15 to generate a forward thrust fr. The magnitude of the rearward thrust fl and the forward thrust fr are equal. As a result, the resultant force of the rearward thrust fl and the forward thrust fr acts on the boat 10 as a lateral movement force F in the left lateral direction.

[0058] At this time, as in the case of moving the boat 10 laterally to the right, the rearward thrust fl of the port-side outboard motor 14 and the forward thrust fr of the starboard-side outboard motor 15 intersect in front of the turning center of gravity G, so the point of application P of the lateral force F is also located in front of the turning center of gravity G. In other words, because the point of application P of the lateral force F does not coincide with the turning center of gravity G, a counterclockwise yaw moment M is generated around the turning center of gravity G by the lateral force F.

[0059] Meanwhile, the BCU 20 rotates the rod 18 of the trolling motor 16 about its axis, causing the trolling motor 16 to generate a thrust force FT in the right lateral direction, which is the opposite direction to the lateral movement force F. This thrust force FT in the right lateral direction generates a counter yaw moment MC, which is a yaw moment in the clockwise direction about the turning center of gravity G. Therefore, the counter yaw moment MC can cancel out the yaw moment M generated by the lateral movement force F in the left lateral direction. Note that in this embodiment as well, the magnitude of the thrust force FT generated by the trolling motor 16 is determined by the above formula (1).

[0060] According to this embodiment, when the boat 10 is moved laterally, the port-side outboard motor 14 and the starboard-side outboard motor 15 form a V-shape in a plan view. Then, the port-side outboard motor 14 and the starboard-side outboard motor 15 generate thrusts fl and fr in opposite directions, generating a lateral movement force F whose point of application P is located forward of the turning center of gravity G. Furthermore, the bow-side trolling motor 16 generates a thrust FT in the opposite direction to the lateral movement force F. This allows the thrust FT to counteract the yaw moment M generated by the lateral movement force F with a counter yaw moment MC. As a result, this embodiment can also achieve the same effects as the first embodiment.

[0061] As described above, in this embodiment, the magnitude of the thrust force FT generated by the trolling motor 16 is also determined by the above formula (1), but in this embodiment, the distance from the lateral moving force F to the turning center of gravity is much smaller than in the first embodiment, while the distance from the turning center of gravity G to the trolling motor 16 is the same as in the first embodiment. Therefore, compared to the first embodiment, the thrust force FT may be much smaller, for example, smaller than the lateral moving force F. As a result, a smaller and lower-output trolling motor 16 can be used.

[0062] In this embodiment, the direction of action of the lateral movement force F is opposite to the direction of action of the thrust force FT generated in the trolling motor 16, so the thrust force FT impedes the lateral movement of the vessel 10. As described above, the thrust force FT is smaller than the lateral movement force F, so the thrust force FT does not stop the lateral movement of the vessel 10. However, from the viewpoint of efficiently moving the vessel 10 in the lateral direction, it is preferable that the thrust force FT generated in the trolling motor 16 is even smaller.

[0063] Therefore, in order to reduce the thrust force FT while maintaining the magnitude of the counter yaw moment MC, in this embodiment as well, the distance from the turning center of gravity G to the propeller 17a that generates the thrust force FT may be increased as in the first embodiment (see FIG. 11). Specifically, the thrust force FT may be generated forward of the bow of the hull 11 (12). Note that in this embodiment as well, it is preferable to increase the distance from the turning center of gravity G to the propeller 17a by providing the configurations shown in FIG. 8.

[0064] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0065] For example, the marine propulsion system according to the embodiment of the present invention has been applied to a pontoon boat, which is a catamaran, but it may also be applied to a wider trimaran boat as long as it has an outboard motor on each of the port and starboard sides, or to a monohull boat having a wide hull shape and a large pitch between the left and right outboard motors. Note that the outboard motor may have an electric motor instead of an engine as a power source.

[0066] In addition, the marine vessel propulsion system according to the embodiment of the present invention may be applied to a marine vessel equipped with three or more outboard motors, and further may be applied not only to a marine vessel equipped with outboard motors at the stern of both sides, but also to a marine vessel equipped with inboard / outboard motors or jet propulsion motors at the stern of both sides.

[0067] In addition, the gist of the present invention (suppressing yaw rotation around the turning center of gravity G during movement by the thrust FT of the trolling motor 16) can be applied not only when the vessel 10 moves laterally, but also when the vessel 10 moves diagonally forward or diagonally backward. [Explanation of symbols]

[0068] 10 vessel, 11, 12 hull, 14 port side outboard motor, 15 starboard side outboard motor, 16 trolling motor, 17a propeller, 18 rod, 32 arm

Claims

1. The vessel includes a plurality of first propulsion units disposed on the stern of a hull, and a second propulsion unit disposed on the bow side of the hull, a ship propulsion system in which, when moving the hull laterally, the first propulsion unit on the port side located to the port side of a center line in the fore-and-aft direction of the hull is steered to the maximum extent in the port turning direction and the first propulsion unit on the starboard side located to the starboard side of the center line is steered to the maximum extent in the right turning direction so that, in a plan view, the first propulsion unit on the port side and the first propulsion unit on the starboard side form a V-shape, and further, the first propulsion unit on the port side generates a forward or rearward thrust and the first propulsion unit on the starboard side generates a thrust in a direction opposite to the thrust generated by the first propulsion unit on the port side, the point of application of a lateral movement force which is a resultant force of the thrust generated by the first propulsion unit on the port side and the thrust generated by the first propulsion unit on the starboard side is located forward of the center of gravity of the hull for turning, A marine vessel propulsion system in which a counter yaw moment is generated by another thrust generated by the second propulsion unit, the counter yaw moment canceling out the yaw moment about the turning center of gravity caused by the lateral movement force.

2. by steering the first propulsion unit on the port side to the right turning direction and steering the first propulsion unit on the starboard side to the left turning direction, the first propulsion unit on the port side and the first propulsion unit on the starboard side form an inverted V shape in a plan view, Furthermore, by causing the first propulsion unit on the port side to generate a forward or rearward thrust and causing the first propulsion unit on the starboard side to generate a thrust in a direction opposite to the thrust generated by the first propulsion unit on the port side, the point of application of a lateral movement force, which is a resultant force of the thrust generated by the first propulsion unit on the port side and the thrust generated by the first propulsion unit on the starboard side, is positioned rearward of the turning center of gravity, The marine vessel propulsion system according to claim 1 , wherein the second propulsion unit generates another thrust in the same direction as the resultant force.

3. 3. The marine vessel propulsion system according to claim 2, wherein even when the first propulsion unit on the port side is steered in a right turning direction and the first propulsion unit on the starboard side is steered in a left turning direction, the first propulsion unit on the port side and the first propulsion unit on the starboard side do not interfere with each other.

4. 4. The vessel propulsion system according to claim 2, wherein the second propulsion unit generates another thrust in the same direction as the resultant force forward of a bow of the vessel.

5. 5. The marine vessel propulsion system according to claim 4, wherein the second propulsion unit has a propeller that generates the other thrust and an extendable arm, and the propeller is moved forward of the bow of the hull by extending the arm.

6. 5. The vessel propulsion system according to claim 4, wherein the second propulsion unit has a propeller that generates the other thrust and an extendable rod, the propeller is disposed at a tip of the rod, and the rod is tilted with respect to the water surface to submerge the propeller forward of the bow of the hull.

7. When the hull is moved laterally to the starboard side, a rearward thrust is generated in the first propulsion unit on the port side, a forward thrust is generated in the first propulsion unit on the starboard side, and another thrust to the starboard side is generated in the second propulsion unit, 7. The marine vessel propulsion system according to claim 2, wherein, when the hull is moved laterally to the port side, the first propulsion unit on the port side generates a forward thrust, the first propulsion unit on the starboard side generates a rearward thrust, and the second propulsion unit generates another thrust to the port side.

8. by steering the first propulsion unit on the port side in the port turning direction and steering the first propulsion unit on the starboard side in the right turning direction, the first propulsion unit on the port side and the first propulsion unit on the starboard side form a V-shape in a plan view, and further by causing the first propulsion unit on the port side to generate a forward or rearward thrust and causing the first propulsion unit on the starboard side to generate a thrust in the opposite direction to the thrust generated by the first propulsion unit on the port side, the point of application of a lateral movement force, which is the resultant force of the thrust generated by the first propulsion unit on the port side and the thrust generated by the first propulsion unit on the starboard side, is positioned forward of the center of gravity of the hull when turning, 2. The marine vessel propulsion system according to claim 1, further comprising a second propulsion unit that generates a second thrust in an opposite direction to the resultant force.

9. The marine vessel propulsion system according to claim 8 , wherein another thrust force in an opposite direction to the resultant force is smaller than the resultant force.

10. 10. The vessel propulsion system according to claim 8, wherein the second propulsion unit generates another thrust in an opposite direction to the resultant force forward of a bow of the hull.

11. 11. The marine vessel propulsion system according to claim 10, wherein the second propulsion unit has a propeller that generates the other thrust and an extendable arm, and the propeller is moved forward of the bow of the hull by extending the arm.

12. 11. The vessel propulsion system according to claim 10, wherein the second propulsion unit has a propeller that generates the other thrust and an extendable rod, the propeller is disposed at a tip of the rod, and the rod is tilted with respect to the water surface to submerge the propeller forward of the bow of the hull.

13. When the hull is moved laterally to the starboard side, a forward thrust is generated in the first propulsion unit on the port side, a rearward thrust is generated in the first propulsion unit on the starboard side, and another thrust toward the port side is generated in the second propulsion unit, 13. A vessel propulsion system according to any one of claims 8 to 12, wherein, when the hull is moved laterally to the port side, the first propulsion unit on the port side generates a rearward thrust, the first propulsion unit on the starboard side generates a forward thrust, and the second propulsion unit generates another thrust to the starboard side.

14. The vessel is provided with a plurality of first propulsion units arranged at the stern of the vessel and a second propulsion unit arranged on the bow side of the vessel, and when the vessel is moved laterally, the first propulsion unit on the port side located on the port side of the center line in the fore-and-aft direction of the vessel is steered to the maximum extent in the port turning direction, and the first propulsion unit on the starboard side located on the starboard side of the center line is steered to the maximum extent in the right turning direction, so that, in a plan view, the first propulsion unit on the port side and the first propulsion unit on the starboard side are steered to the maximum extent in the right turning direction. a control method for a marine vessel propulsion system in which, when the first propulsion unit forms a V-shape, and further, the first propulsion unit on the port side is caused to generate a forward or rearward thrust and the first propulsion unit on the starboard side is caused to generate a thrust in an opposite direction to the thrust generated by the first propulsion unit on the port side, a point of application of a lateral movement force which is a resultant force of the thrust generated by the first propulsion unit on the port side and the thrust generated by the first propulsion unit on the starboard side is located forward of a center of gravity for turning of the hull, A method for controlling a marine vessel propulsion system, comprising: generating a counter yaw moment by another thrust generated by the second propulsion unit, the counter yaw moment canceling out the yaw moment about the turning center of gravity caused by the lateral movement force.

15. A marine vessel including a marine vessel propulsion system, the vessel propulsion system includes a plurality of first propulsion units disposed on a stern side of a hull and a second propulsion unit disposed on a bow side of the hull, In the vessel propulsion system, when the hull is moved laterally, the first propulsion unit on the port side located on the port side of the center line in the fore-and-aft direction of the hull is steered to the maximum extent in the port turning direction, and the first propulsion unit on the starboard side located on the starboard side of the center line is steered to the maximum extent in the right turning direction, so that in a plan view, the first propulsion unit on the port side and the first propulsion unit on the starboard side form a V-shape, and further, the first propulsion unit on the port side is steered to the maximum extent in the forward or rearward direction. a lateral force acting as a result of the thrust generated by the first propulsion unit on the port side and the thrust generated by the first propulsion unit on the starboard side is generated in a direction opposite to the thrust generated by the first propulsion unit on the port side, the point of application of this lateral force, which is the resultant force of the thrust generated by the first propulsion unit on the port side and the thrust generated by the first propulsion unit on the starboard side, is located forward of the center of gravity of the hull for turning, and a counter yaw moment is generated by another thrust generated by the second propulsion unit to cancel out the yaw moment about the center of gravity of the turning due to the lateral force.

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