Propulsion system of boat

Abstract

A propulsion system of a boat includes: a trim angle adjuster configured to adjust a trim angle of each of propulsion machines on both sides in a left-right direction; and a controller configured to control the trim angle adjuster, in which the controller is capable of conducting trim support control and heel control, the trim support control adjusting the trim angle to a trim support angle set in accordance with a boat speed, the heel control adjusting the trim angle to a heel suppression angle set in accordance with an inclination in a roll direction of a hull to suppress the inclination in the roll direction of the hull, and in a case where a preset condition is satisfied, the controller conducts the heel control in addition to the trim support control, and causes the trim angle adjuster to adjust the trim angle to the heel suppression angle set with reference to the trim support angle of the propulsion machine.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] Priority is claimed on Japanese Patent Application No. 2025-057486, filed Mar. 31, 2025, the content of which is incorporated herein by reference.BACKGROUND OF THE INVENTIONField of the Invention

[0002] The present invention relates to a propulsion system of a boat.Description of Related Art

[0003] Various techniques for automatically controlling a propulsion system of a boat have been conventionally proposed in order to improve stability, acceleration, a maximum speed, energy efficiency, and the like, in navigating the boat.

[0004] For example, Japanese Patent No. 5059392 discloses a constitution related to heel control of controlling a heel angle of a boat. In this constitution, in a case where it is determined that the boat is not turning in accordance with the steering angle of the steering mechanism of the boat, the heel angle of the boat is increased in a direction corresponding to the steering angle of the steering mechanism by generating a difference between the left lift force and right lift force of the boat.SUMMARY OF THE INVENTION

[0005] In the boat, by the way, not only the heel control but also another type of control is conducted in accordance with a navigation state of the boat in some cases. For example, at the time of accelerating or cruising, trim support control of adjusting a trim angle to an optimum position in accordance with the boat speed or the rotation speed of the propulsion machine is conducted in some cases.

[0006] Such heel control and trim support control can be conducted individually, or can be conducted simultaneously. Hence, there is a demand for smoothly conducting the heel control and the trim support control in accordance with the navigation state of the boat to improve the stability, the acceleration, the maximum speed, the energy efficiency, and the like.

[0007] The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a propulsion system of a boat capable of smoothly conducting heel control and trim support control in accordance with a navigation state of the boat to improve stability, acceleration, a maximum speed, energy efficiency, and the like.

[0008] In order to solve the above problems, the present disclosure adopts the following aspects.

[0009] (1) A propulsion system of a boat according to one aspect of the present disclosure, includes: at least one propulsion machine including a drive source, and a propulsor configured to generate thrust with dynamic power transmitted from the drive source, the at least one propulsion machine being provided on each of both sides in a left-right direction with respect to a center of a hull; a trim angle adjuster configured to adjust a trim angle of each of the propulsion machines on the both sides in the left-right direction with respect to the hull; and a controller configured to control the trim angle adjuster, in which the controller is capable of conducting trim support control and heel control, the trim support control causing the trim angle adjuster to adjust the trim angle to a trim support angle set in accordance with either a preset boat speed or a rotation speed of a propulsion machine, the heel control causing the trim angle adjuster to adjust the trim angle to a heel suppression angle set in accordance with an inclination in a roll direction of the hull to suppress the inclination in the roll direction of the hull, and in a case where a preset condition is satisfied, the controller conducts the heel control in addition to the trim support control, and causes the trim angle adjuster to adjust the trim angle to the heel suppression angle set with reference to the trim support angle of the propulsion machine.

[0010] (2) The propulsion system of the boat according to the above aspect (1) may further include a heel angle detector configured to detect a heel angle corresponding to an inclination in a roll direction of the hull, in which in a case where the heel angle is equal to or larger than a preset heel angle reference value, the controller may conduct the heel control.

[0011] (3) The propulsion system of the boat according to the above aspect (1) or (2) may further include a steering angle detector configured to detect a steering angle around a steering shaft of the propulsion machine with respect to the hull, in which in a case where it is determined that the boat is advancing straight, based on a detection value of a steering angle detected by the steering angle detector, the controller may enable conducting the heel control.

[0012] (4) In the propulsion system of the boat according to the above aspect (3), in a case where it is determined that the boat is turning, based on a detection value of the steering angle of the steering angle detector, the controller may stop conducting the trim support control and the heel control.

[0013] (5) The propulsion system of the boat according to one of the above aspects (1) to (4) may further include a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, in which while conducting the trim support control and the heel control, upon receipt of an operation input from the trim angle operation unit, the controller may stop conducting the heel control.

[0014] (6) In the propulsion system of the boat according to the above aspect (5), in a state in which the operation input from the trim angle operation unit is received and conducting the heel control is stopped, and in a case where a preset return condition is satisfied, the controller may enable conducting the heel control.

[0015] (7) In the propulsion system of the boat according to one of the above aspects (1) to (6), in conducting the trim support control, the controller may set the trim support angles of the propulsion machines on the both sides in the left-right direction to an identical value.

[0016] (8) In the propulsion system of the boat according to one of the above aspects (1) to (7), in conducting the heel control, the controller may set the heel suppression angle of the propulsion machine on one side in the left-right direction to a value larger than the trim support angle, and may also set the heel suppression angle of the propulsion machine on the other side in the left-right direction to a value smaller than the trim support angle.

[0017] (9) The propulsion system of the boat according to one of the above aspects (1) to (8) may further include an intermediate member provided between the hull and the propulsion machine, the intermediate member increasing a rearward inclination angle in a propulsion direction of the propulsion machine.

[0018] According to the aspect (1), in a case where the preset condition is satisfied, the heel control is conducted in addition to the trim support control, and the trim angle adjuster is caused to adjust the trim angle to the heel suppression angle set with reference to the trim support angle of the propulsion machine. Accordingly, in the case where the preset condition is satisfied, the heel control is conducted in addition to the trim support control, and thus it becomes possible to suppress the heel angle of the boat while automatically adjusting the trim angle. Therefore, it becomes possible to smoothly conduct the heel control and the trim support control in accordance with the navigation state of the boat, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0019] According to the aspect (2), the heel control is conducted when the heel angle is equal to or larger than the preset heel angle reference value. Thus, as the preset conditions, while the boat is advancing straight and in the case where the heel angle is large, it becomes possible to suppress the heel angle, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat can be improved.

[0020] According to the aspect (3), conducting the heel control is enabled when it is determined that the boat is advancing straight, based on the detection value of the steering angle. Thus, as the preset condition, while the boat is advancing straight, it becomes possible to smoothly conduct the heel control, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0021] According to the aspect (4), in a case where it is determined that the boat is turning, based on the detection value of the steering angle, conducting the trim support control and the heel control is stopped. Thus, while the boat is turning, it becomes possible to suppress inhibition of the turning property due to the heel control or the trim support control.

[0022] According to the aspect (5), while conducting the heel control, upon receipt of the operation input from the trim angle operation unit, conducting the heel control is stopped. Thus, when the trim angle is manually operated by the boat operator of the boat, conducting the heel control is stopped, so that an uneasy feeling of the boat operator who has operated the trim angle can be suppressed.

[0023] According to the aspect (6), in a state in which the heel control is stopped upon receipt of the operation input from the trim angle operation unit, and in a case where a preset return condition is satisfied, conducting the heel control is enabled. Thus, after the trim angle is manually operated by the boat operator of the boat and conducting the heel control is stopped, in a case where a preset return condition is satisfied, it becomes possible to transition the state to the standby state that enables conducting the heel control.

[0024] According to the aspect (7), in conducting the trim support control, the trim support angles of the propulsion machines on both sides in the left-right direction are set to the same value. Thus, the trim angle can be effectively adjusted in the boat in the straight advancing state.

[0025] According to the aspect (8), in conducting the heel control, the heel suppression angle of the propulsion machine on one side in the left-right direction is set to a value larger than the trim support angle, and the heel suppression angle of the propulsion machine on the other side in the left-right direction is also set to a value smaller than the trim support angle. Thus, in a case where the heel angle of the boat is large, the heel angle can be suppressed satisfactorily.

[0026] According to the aspect (9), an intermediate member for increasing the inclination angle of the propulsion machine rearward in the propulsion direction is provided between the hull and the propulsion machine. Thus, it becomes possible to further largely incline the propulsion machine rearward in the propulsion direction of the boat, so that the trim angle can be made larger in the negative direction. Therefore, in a case where the heel angle of the boat is large, the heel angle can be more effectively suppressed.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a plan view of a boat according to an embodiment;

[0028] FIG. 2 is a functional block diagram of a propulsion system of the above boat;

[0029] FIG. 3 is a side view of a propulsion machine of the above propulsion system;

[0030] FIG. 4 is a diagram illustrating an example of trim support control, heel control, hump control, and bogen control to be conducted in accordance with a boat speed in the above propulsion system;

[0031] FIG. 5 is a diagram illustrating an example of a set value of a trim support angle in the trim support control, the heel control, and the hump control to be conducted in accordance with the boat speed in above the propulsion system;

[0032] FIG. 6 is a view illustrating a state in which the trim support control is being conducted in the above propulsion system;

[0033] FIG. 7 is a view illustrating a state of conducting the heel control in a state in which the above boat is inclined to a port side;

[0034] FIG. 8 is a view illustrating a state of conducting the heel control in a state in which the above boat is inclined to a starboard side;

[0035] FIG. 9 is a flowchart illustrating a method for conducting the heel control while conducting the trim support control; and

[0036] FIG. 10 is a timing chart illustrating an example of the operation of the above propulsion system.DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that it is assumed that front, rear, upper, lower, left, and right directions in the following description respectively coincide with the directions of a boat 1. In this case, an arrow FR in the drawing indicates a forward side of the boat 1, an arrow UP in the drawing indicates an upper side of the boat 1, and an arrow LH in the drawing indicates a leftward side of the boat 1. In addition, a center line CL indicates the center position of the boat 1 in a left-right direction (a width direction).

[0038] FIG. 1 is a plan view of the boat according to an embodiment. FIG. 2 is a functional block diagram of a propulsion system of the boat.

[0039] As illustrated in FIG. 1, the boat 1 includes: a hull 2; and a propulsion system 20, which is provided on the hull 2.

[0040] As illustrated in FIGS. 1 and 2, the propulsion system 20 includes a plurality of propulsion machines 3, an operation unit 7, a detector 6 (see FIG. 2), and a controller 8 (see FIG. 2).Propulsion Machine

[0041] As illustrated in FIG. 1, the propulsion machine 3 includes: a right propulsion machine 3a, which is provided on the right of a stern 2b with respect to the center line CL; and a left propulsion machine 3b, which is provided on the left of the stern 2b, with respect to the center line CL. The two propulsion machines 3 (the right propulsion machine 3a and the left propulsion machine 3b) are provided on the stern 2b of the hull 2 respectively on both right and left sides of the stern 2b, interposing the center line CL between them. That is, the boat 1 in the present embodiment is a so-called small-sized boat in which the two propulsion machines are provided. Hereinafter, in a case where it is not necessary to distinguish between the propulsion machines 3a and 3b, they will be collectively described as the propulsion machine 3.

[0042] FIG. 3 is a side view of a propulsion machine of the propulsion system.

[0043] As illustrated in FIG. 3, the propulsion machine 3 is, for example, an outboard motor. The propulsion machine 3 includes: a casing 31; a drive source 32; a drive shaft 33; a propulsor 34; and a shift switching mechanism 35.

[0044] The casing 31 is attached to a bracket 22, which is provided on the stern 2b, via a steering shaft (a swivel shaft) 36, which extends in an up-down direction. The propulsion machine 3 is attached to the hull 2 so as to be rotatable around the steering shaft 36 in accordance with the operation of a steering actuator 41 (see FIG. 2).

[0045] The drive source 32 is, for example, an internal combustion engine such as an engine. The drive source 32 is accommodated in an upper portion of the casing 31 with a crankshaft extending in the up-down direction. Dynamic power (an engine speed) of the drive source 32 is set, based on an opening degree of a throttle valve. The throttle valve is driven by the operation of a throttle actuator 42 (see FIG. 2). Note that the drive source 32 may be an electric motor.

[0046] The drive shaft 33 transmits the dynamic power generated by the drive source 32 to the propulsor 34 via the shift switching mechanism 35. The drive shaft 33 extends in the up-down direction in the casing 31. An upper end portion of the drive shaft 33 is connected with the drive source 32.

[0047] The propulsor 34 includes a propeller shaft 341 and propellers 342.

[0048] The propeller shaft 341 is provided at a lower end portion of the casing 31 so as to be rotatable around an axis along a front-rear direction. A front end portion of the propeller shaft 341 is connected with the shift switching mechanism 35 in the casing 31.

[0049] The propellers 342 are provided projecting outside of the casing 31 at a rear end portion of the propeller shaft 341. The propellers 342 rotate integrally with the propeller shaft 341.

[0050] The shift switching mechanism 35 includes a drive gear 351, a forward gear 352, a reverse gear 353, and a clutch 354.

[0051] The drive gear 351 is provided at a lower end portion of the drive shaft 33. The drive gear 351 is rotatable integrally with the drive shaft 33.

[0052] The forward gear 352 and the reverse gear 353 are rotatably provided at positions facing each other in the front-rear direction, interposing the drive gear 351 between them on the propeller shaft 341. The forward gear 352 and the reverse gear 353 are capable of meshing with the drive gear 351. The forward gear 352 and the reverse gear 353 rotate in opposite directions to each other in accordance with the rotation of the drive gear 351.

[0053] The clutch 354 switches between a connection state and a disconnection state of the dynamic power between either the forward gear 352 or the reverse gear 353 and the propeller shaft 341. The clutch 354 is provided to be rotatable integrally with the propeller shaft 341. The clutch 354 is provided to be movable in the front-rear direction along the propeller shaft 341 in accordance with the operation of a shift actuator 43. The clutch 354 alternatively meshes with the forward gear 352 and the reverse gear 353 to switch the rotation directions of the propeller shaft 341 and the propellers 342, and is capable of switching the propulsion direction of the boat 1.

[0054] The propulsion machine 3 is supported by the bracket 22, which is attached to the stern 2b of the hull 2, so as to be rotatable around a support shaft 38, which extends in the left-right direction. This enables the propulsion machine 3 to be rotatable (swingable) around the support shaft 38 with respect to a reference plane Fv. Here, the reference plane Fv denotes a virtual plane along a vertical plane that passes through the center axis of the support shaft 38 when the hull 2 is simply floated on the water surface.

[0055] Here, a trim angle θt is defined as an angle at which the direction in which the steering shaft 36 of the propulsion machine 3 extends is inclined in the front-rear direction around the support shaft 38 with respect to the reference plane Fv. In the present embodiment, with regard to the trim angle θt, a positive (plus) direction represents a direction in which a lower end portion of the propulsion machine 3 is apart rearward from the stern 2b, and a negative (minus) direction represents a direction in which the lower end portion of the propulsion machine 3 approaches the stern 2b.

[0056] The trim angle θt of the propulsion machine 3 is adjustable by a trim angle adjuster 45. The trim angle adjuster 45 uses an actuator, not illustrated, to rotate the propulsion machine 3 around the support shaft 38 within a preset angle range. The rotation of the propulsion machine 3 in the positive direction and the negative direction is restricted by hitting a stopper, not illustrated, or the like provided on the bracket 22.

[0057] In the present embodiment, the bracket 22 is attached to an attachment surface 2f, which is formed on the stern 2b, via an intermediate member 37. The intermediate member 37 is sandwiched between the bracket 22 and the attachment surface 2f. The intermediate member 37 is formed in a wedge shape having a thickness in the front-rear direction gradually decreasing from the top to the bottom. Thus, the bracket 22 is provided to be further inclined rearward than a case of being directly attached to the attachment surface 2f without the use of the intermediate member 37. This constitution enables setting of a larger rotation angle (rotation range) of the propulsion machine 3 in the negative direction.Operation Unit

[0058] As illustrated in FIGS. 1 and 2, the operation unit 7 is provided to allow a boat operator to perform an operation input in order to navigate the boat 1. In the present embodiment, the operation unit 7 includes, for example, a steering angle inputter 71, a thrust inputter 72, a trim angle operation unit 73, and an operation inputter 74.

[0059] The steering angle inputter 71 is provided in a cockpit of the hull 2. The steering angle inputter 71 is, for example, a steering wheel provided to be rotatable clockwise and counterclockwise. The steering angle inputter 71 receives an operation input by the boat operator from the outside, in changing the course of the boat 1 (the hull 2). That is, the steering angle inputter 71 receives an operation, by the boat operator, for changing the direction (the steering angle) of the propulsion machine 3 around the steering shaft 36. The steering angle denotes an inclination angle of the propulsion machine 3 with respect to the center line CL in a plan view. In the present embodiment, the steering angle of the propulsion machine 3 when the course of the boat 1 is the straight advancing direction is set as the reference value (0 degrees). Note that as the steering angle inputter 71, in addition to the steering wheel, a joystick may be used, and the steering angle inputter 71 may be mounted as a switch or the like of the operation inputter 74.

[0060] The thrust inputter 72 is provided in the cockpit of the hull 2. The thrust inputter 72 is, for example, a throttle lever. In changing the thrust of the propulsion machine 3 or the shift position of the propulsion machine 3, the thrust inputter 72 receives an operation input from the outside by the boat operator. The thrust inputter 72 is constituted to be capable of reciprocating in accordance with rotation, sliding, or the like. The thrust inputter 72 is capable of reciprocating within an operation region in which three shift regions of the forward position F, the neutral position N, and the reverse position R are aligned. When the thrust inputter 72 is located at the forward position F, the propulsion machine 3 exerts thrust for moving the boat 1 forward. When the thrust inputter 72 is located at the reverse position R, the propulsion machine 3 exerts thrust for moving the boat 1 rearward. When the thrust inputter 72 is located at the neutral position N, the drive gear 351, which is illustrated in FIG. 3, is disconnected from the forward gear 352 and the reverse gear 353, and the propulsion machine 3 does not exert thrust for propelling the boat 1.

[0061] As illustrated in FIG. 1, a trim angle operation switch is provided as the trim angle operation unit 73 in the vicinity of the thrust inputter 72. The boat operator of the boat 1 is able to change the trim angle θt of the propulsion machine 3 by manually operating the trim angle operation switch (the trim angle operation unit 73).

[0062] The operation inputter 74 receives various operations on the boat 1. The operation inputter 74 is constituted to be manually operable by the boat operator, such as a multi-function display (MFD). Note that the operation inputter 74 may be an external device such as a mobile terminal connected to the boat 1 in a wired or wireless manner.Detector

[0063] The detector 6 illustrated in FIG. 2 detects a state (a navigation state) of the boat 1. In the present embodiment, the detector 6 includes a position sensor 61, a boat speed sensor 62, a steering angle sensor (a steering angle detector) 63, an inertial sensor 64, a trim operation sensor 65, a trim angle sensor 66, and an actual steering angle sensor 67.

[0064] The position sensor 61 detects the position of the thrust inputter 72. The position sensor 61 outputs, to the controller 8, a detection signal based on the position of the thrust inputter 72.

[0065] As illustrated in FIG. 2, the boat speed sensor 62 detects a boat speed V of the boat 1. The boat speed sensor 62 is, for example, a global positioning system (GPS) or the like, and calculates the boat speed V, based on a positioning signal from a positioning satellite. Note that the boat speed sensor 62 may be an acoustic sensor or an electromagnetic sensor that detects the boat speed (a boat speed relative to the water) V of the boat 1. The boat speed sensor 62 may estimate the boat speed V, based on the engine speed. The boat speed sensor 62 outputs a signal indicating the detected boat speed V to the controller 8.

[0066] The steering angle sensor 63 detects an operation amount (a steering instruction angle) in accordance with the rotation operation on the steering angle inputter 71. The steering angle sensor 63 outputs, to the controller 8, a detection signal based on the steering instruction angle on the steering angle inputter 71.

[0067] The inertial sensor 64 detects the inclination in the roll direction of the hull 2, that is, a heel angle θh. The inertial sensor 64 is also capable of detecting an inclination or the like in the pitch direction of the hull 2. The inertial sensor 64 outputs, to the controller 8, detection signals based on the detected inclinations in the roll direction and the pitch direction of the hull 2.

[0068] The trim operation sensor 65 detects whether an operation input has been made on the trim angle operation switch, which serves as the trim angle operation unit 73. The trim operation sensor 65 outputs, to the controller 8, a detection signal indicating the presence or absence of the detected operation input.

[0069] The trim angle sensor 66 is provided in the trim angle adjuster 45. The trim angle sensor 66 detects an actual trim angle θt to be adjusted by the trim angle adjuster 45. The trim angle sensor 66 outputs, to the controller 8, a detection signal indicating the detected trim angle θt.

[0070] The actual steering angle sensor 67 is provided on the steering actuator 41. The actual steering angle sensor 67 detects the actual steering angle of the propulsion machine 3, and outputs the actual steering angle to the controller 8.Controller

[0071] The controller 8 integrally controls the operation of the boat 1 (the propulsion machine 3). The controller 8 is an integrated electronic control device or a plurality of electronic control devices included in the boat 1. The controller 8 is implemented by, for example, a hardware processor such as a central processing unit (CPU) executing a program (software) stored in a storage 80 such as a read only memory (ROM), a random access memory (RAM), or the like. Some or all of these constituent elements may be implemented by a hardware (a circuit part; including circuitry) such as a large scale integration (LSI), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a graphics processing unit (GPU), or system on chip (SOC), or may be implemented by software and hardware in cooperation.

[0072] The controller 8 includes a storage 80, an acquisitor 81, a determiner 82, and a drive processor 83.

[0073] The storage 80 records programs, various data, and the like necessary for navigation of the boat 1, such as the trim support control, the heel control, the hump control, and the bogen control.

[0074] The acquisitor 81 acquires detection results of various sensors of the detector 6.

[0075] The determiner 82 determines the state of the boat 1, based on information obtained by the acquisitor 81 and information stored in the storage 80.

[0076] The drive processor 83 controls operations of various actuators, based on a determination result by the determiner 82 and the information stored in the storage 80 or the acquisitor 81. In the present embodiment, in a case where the determiner 82 determines that a predetermined condition is satisfied, the drive processor 83 controls the operations of the trim angle adjuster 45, the steering actuator 41, and the like to conduct the trim support control, the heel control, the hump control, and the bogen control. In the present embodiment, when the boat 1 is in a straight advancing state, the drive processor 83 conducts the trim support control, the heel control, the hump control, and the bogen control. In the present embodiment, the drive processor 83 does not conduct the bogen control, when the boat 1 is not in the straight advancing state.Trim Support Control

[0077] FIG. 4 is a diagram illustrating an example of the trim support control, the heel control, the hump control, and the bogen control to be conducted in accordance with the boat speed in the propulsion system.

[0078] As illustrated in FIG. 4, when the boat 1 is in the straight advancing state, the drive processor 83 conducts the trim support control in the regions of the heel control, the hump control, and the bogen control in accordance with settings by the boat operator to be input from the trim angle operation unit 73 and the operation inputter 74, for example.

[0079] FIG. 5 is a diagram illustrating an example of set values of the trim support angles in the trim support control, the heel control, and the hump control to be conducted in accordance with the boat speed in the propulsion system.

[0080] As illustrated in FIG. 5, in the trim support control, the trim angle adjuster 45 is caused to adjust a trim angle θt to be a trim support angle θsp, which is set in accordance with a preset boat speed V (or rotation speed of the propulsion machine). In the present embodiment, in the trim support control, the trim support angle θsp is set in accordance with the boat speed V to optimize stability, acceleration, a maximum speed, energy efficiency, and the like. The trim support angle θsp may be set in accordance with the rotation speed of the propulsion machine. Therefore, in the storage 80, the boat speed V (or the rotation speed of the propulsion machine) and the trim support angle θsp, at which the stability, the acceleration, the maximum speed, the energy efficiency, and the like are optimized, are stored beforehand in association with each other. In the example of FIG. 5, the trim support angle θsp is set in a stepwise manner with respect to the boat speed V (or the rotation speed of the propulsion machine).

[0081] The drive processor 83 acquires, from the storage 80, the trim support angle θsp, which is associated with the boat speed acquired by the acquisitor 81.

[0082] The drive processor 83 controls the trim angle adjuster 45 so that the trim angle θt of the propulsion machine 3 approaches the acquired trim support angle θsp.

[0083] FIG. 6 is a view illustrating a state in which the trim support control is being conducted in the propulsion system.

[0084] As illustrated in FIG. 6, in conducting the trim support control, the drive processor 83 sets the trim support angles θsp of the propulsion machines 3a and 3b on both sides in the left-right direction to the same value.Heel Control

[0085] As illustrated in FIG. 4, when the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the second threshold V2, while the trim support control is being conducted, and in a case where the determiner 82 determines that a preset condition is satisfied, the drive processor 83 conducts the heel control in addition to the trim support control. Specifically, when the boat 1 is in the straight advancing state, while the trim support control is being conducted, and when the boat speed becomes equal to or higher than the second threshold V2, the drive processor 83 conducts the heel control in addition to the trim support control, that is, both the trim support control and the heel control.

[0086] In this case, the drive processor 83 conducts the heel control, in a case where the heel angle θh, which is detected by the inertial sensor 64, and which is the inclination in the roll direction of the hull 2, is equal to or larger than a preset heel angle reference value θhs (for example, several degrees). That is, in a case where the heel angle θh is smaller than the heel angle reference value θhs, the drive processor 83 continuously conducts the trim support control without conducting the heel control.

[0087] In conducting the heel control, the drive processor 83 sets a heel suppression angle θd as a target value in accordance with the heel angle θh of the hull 2. Here, the heel suppression angle θd denotes a trim angle of the propulsion machines 3 on both sides in the left-right direction for suppressing the inclination in the roll direction of the hull 2. The drive processor 83 calculates a heel suppression angle θd, which is capable of effectively suppressing the inclination in the roll direction of the hull 2, in accordance with the heel angle θh of the hull 2 in a preset calculation formula.

[0088] The drive processor 83 sets the heel suppression angle θd with reference to the trim support angle θsp of the propulsion machine 3 at such a timing. With regard to the trim support angle θsp, the drive processor 83 sets the heel suppression angle θd of the propulsion machine 3 on one side in the left-right direction to a value larger than the trim support angle θsp, and also sets the heel suppression angle θd of the propulsion machine 3 on the other side in the left-right direction to a value smaller than the trim support angle θsp.

[0089] FIG. 7 is a view illustrating a state of conducting the heel control in a state in which the boat is inclined to the port side. FIG. 8 is a view illustrating a state of conducting the heel control in a state in which the boat is inclined to the starboard side.

[0090] For example, as illustrated in FIG. 7, when the hull 2 is inclined to the port side, the drive processor 83 sets a heel suppression angle θd2 of the right propulsion machine 3a to a value larger than the trim support angle θsp, and sets a heel suppression angle θd1 of the left propulsion machine 3b to a value smaller than the trim support angle θsp. For example, as illustrated in FIG. 8, when the hull 2 is inclined to the starboard side, the drive processor 83 sets the heel suppression angle θd1 of the left propulsion machine 3b to a value larger than the trim support angle θsp, and sets the heel suppression angle θd2 of the right propulsion machine 3a to a value smaller than the trim support angle θsp.

[0091] The drive processor 83 calculates the heel suppression angles θd1 and θd2 with reference to the trim support angle θsp set at such a timing, based on the heel angle θh of the hull 2 at such a timing that has been acquired by the acquisitor 81. The drive processor 83 calculates, in a preset calculation formula, a trim angle addition value Δθt1 to be added to the trim support angle θsp as a reference for the propulsion machine 3 on one side in the left-right direction and a trim angle subtraction value Δθt2 to be subtracted from the trim support angle θsp as a reference for the propulsion machine 3 on the other side in the left-right direction. Here, the absolute value of the trim angle addition value Δθt1 and the absolute value of the trim angle subtraction value Δθt2 are preferably identical to each other.

[0092] When the hull 2 is inclined to the port side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the following equation (1), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the following equation (2).θ⁢d⁢1=θ⁢sp-Δ⁢θ⁢t⁢2(1)θ⁢d⁢2=θ⁢sp+Δθ⁢t⁢1(2)

[0093] When the hull 2 is inclined to the starboard side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the following equation (3), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the following equation (4).θ⁢d⁢1=θ⁢sp+Δ⁢θ⁢t⁢1(3)θ⁢d⁢2=θ⁢sp-Δθ⁢t⁢2(4)

[0094] The drive processor 83 sets the heel suppression angles θd1 and θd2 that have been calculated to the target values, and causes the trim angle adjuster 45 to adjust the trim angles θt of the propulsion machines 3 (3a, 3b) so as to approach the heel suppression angles θd1 and θd2.

[0095] While conducting the heel control, in a case where the determiner 82 determines that the boat speed V becomes equal to or lower than a preset third threshold V3, the drive processor 83 stops conducting the heel control. Here, the third threshold V3 is set to be lower than the second threshold V2.

[0096] In addition, while conducting the heel control, in a case where the steering angle sensor 63 receives the input of the steering angle from the steering angle inputter 71, the determiner 82 determines whether the boat 1 is turning, based on a detection value of the propulsion machine 3 by the actual steering angle sensor 67. In a case where it is determined that the boat 1 is turning, the drive processor 83 stops conducting the trim support control and the heel control.

[0097] In addition, while conducting the heel control, in a case where the determiner 82 determines that the operation input by the boat operator is received from the trim angle operation unit 73, the drive processor 83 stops conducting the heel control.Hump Control

[0098] In addition, as illustrated in FIG. 4, when the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the first threshold V1, and in a case where the determiner 82 determines that a preset condition is satisfied, the drive processor 83 conducts the hump control.

[0099] The hump control is conducted to suppress excessive lifting of a bow 2a when the bow 2a is largely lifted with respect to the stern 2b. In conducting the hump control, the drive processor 83 sets the trim angles θt of the propulsion machines 3a and 3b on both sides in the left-right direction to the same value.Bogen Control

[0100] In addition, in a case where the boat speed V is lower than the first threshold V1, the drive processor 83 conducts the bogen control. In the bogen control, the plurality of propulsion machines 3 are steered in a direction intersecting the front-rear direction of the hull 2 in a yaw direction. When the boat 1 is in the straight advancing state and the boat speed V is lower than the first threshold V1, the left and right propulsion machines 3 are rotated in directions opposite to each other around the swivel axis and at almost the same steering angle in the bogen control. It becomes possible to reduce the forward propulsion force that works on the entirety of the hull 2 and to navigate the hull 2 at a low speed or an extremely low speed in the bogen control, as compared with a case where the propulsion machines 3 are disposed in parallel with the front-rear direction of the hull 2. Note that in the present embodiment, there is no limitation to the specific content of the bogen control.Control Method of Propulsion System

[0101] Next, an operation method of the propulsion system will be described. Processing to be described below is repeatedly performed, for example, at a predetermined control cycle (for example, several tens of milliseconds).

[0102] Here, the trim support control is conducted at an appropriate timing in accordance with a setting of the boat operator. In the trim support control, the controller 8 sets the trim support angle θsp at which the stability, the acceleration, the maximum speed, the energy efficiency, and the like are optimized as the target value in accordance with the boat speed V acquired in step S11. The controller 8 controls the trim angle adjuster 45 so that the trim angles θt of both the left and right propulsion machines 3 approach the trim support angle θsp, which is set as the target value.

[0103] FIG. 9 is a flowchart illustrating a method for conducting the heel control while conducting the trim support control.

[0104] While conducting the trim support control, the controller 8 causes the acquisitor 81 to acquire a detection result of the boat speed in the boat speed sensor 62 at a predetermined control cycle, in step S141.

[0105] In step S142, the controller 8 determines whether the boat speed V is equal to or higher than the second threshold V2, based on the detection result of the boat speed sensor 62.

[0106] In a case where the determination result in step S142 is “No” (V<V2), the processing ends. The trim support control continues.

[0107] In a case where the determination result in step S142 is “Yes” (V≥V2), the processing proceeds to step S143, and the controller 8 enables conducting the heel control. In other words, the controller 8 sets the heel control to a standby state.

[0108] Next, in step S144, the acquisitor 81 acquires a detection result of the heel angle θh of the hull 2 in the inertial sensor 64.

[0109] In step S145, it is determined whether the heel angle θh is equal to or larger than the heel angle reference value θhs, based on the detection result of the inertial sensor 64.

[0110] In a case where the determination result in step S145 is “No” (θh<θhs), the processing returns to step S144. After a predetermined control cycle elapses, step S144 is repeatedly performed.

[0111] In a case where the determination result in step S145 is “Yes” (θh≥θhs), the processing proceeds to step S146.

[0112] In step S146, the controller 8 conducts the heel control in addition to the trim support control. In step S146, the controller 8 sets the heel suppression angle θd in accordance with the heel angle θh of the hull 2. The controller 8 sets the heel suppression angle θd with reference to the trim support angle θsp of the propulsion machine 3 at such a timing. The drive processor 83 calculates the trim angle addition value Δθt1 to be added to the trim support angle θsp as a reference for the propulsion machine 3 on one side in the left-right direction and the trim angle subtraction value Δθt2 to be subtracted from the trim support angle θsp as a reference for the propulsion machine 3 on the other side in the left-right direction in a preset calculation formula, based on the heel angle θh of the hull 2 at such a timing that has been acquired by the acquisitor 81.

[0113] In a case where the hull 2 is inclined to the port side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the above equation (1), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the above equation (2). In a case where the hull 2 is inclined to the starboard side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the above equation (3), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the above equation (4).

[0114] The drive processor 83 sets the heel suppression angles θd1 and θd2 that have been calculated to the target values, and causes the trim angle adjuster 45 to adjust the trim angles θt of the propulsion machines 3 (3a and 3b).

[0115] In step S147, while conducting the heel control, it is determined whether a predetermined stop condition for stopping the heel control is satisfied. In the present embodiment, as a predetermined stop condition for stopping the heel control, examples include

[0116] Condition 1: While conducting the heel control, a case where the boat speed V becomes equal to or lower than a preset third threshold V3, and

[0117] Condition 2: A case of receiving an operation input by the boat operator from the trim angle operation unit 73.

[0118] In a case where the determination result in step S147 is “No” (in a case where neither the condition 1 nor the condition 2 is satisfied), the processing proceeds to step S149.

[0119] In a case where the determination result in step S147 is “Yes” (in a case where at least one of the conditions 1 and 2 is satisfied), the processing proceeds to step S148, conducting the heel control is stopped, and only the trim support control is continuously conducted.

[0120] In step S147, upon receipt of the operation input from the trim angle operation unit 73, in a case where conducting the heel control is stopped in step S148, then the determiner 82 determines in step S151 whether a preset return condition is satisfied at every predetermined control cycle. Here, as the return condition, examples include

[0121] Condition 3: A case where the boat speed V changes from outside of the heel control region (equal to or smaller than the third threshold V3) to inside the heel control region (equal to or larger than the second threshold V2), and

[0122] Condition 4: A case where the boat 1 changes from a turning state to a straight advancing state.

[0123] In a case where the determination result in step S151 is “Yes” (in a case where at least one of the conditions 3 and 4 is satisfied), the processing proceeds to step S149.

[0124] In step S149, the controller 8 determines whether the boat 1 is turning. In this case, the controller 8 causes the steering angle sensor 63 to determine whether the boat 1 is turning, based on the input value of the steering angle from the steering angle inputter 71.

[0125] In a case where the determination result in step S149 is “No” (when the boat 1 is not turning, that is, when the boat 1 is advancing straight), the processing ends. After a predetermined control cycle elapses, the above processing is repeatedly performed.

[0126] In a case where the determination result in step S149 is “Yes” (when the boat 1 is turning), the processing proceeds to step S150, and conducting the trim support control and the heel control is stopped.

[0127] In a case where conducting the trim support control and the heel control is stopped in step S150, then the determiner 82 determines in step S152 whether a preset return condition is satisfied at every predetermined control cycle. Here, as the return condition, an example includes

[0128] Condition 5: A case where the boat 1 changes from a turning state to a straight advancing state.

[0129] In a case where the determination result in step S152 is “Yes” (in a case where the condition 5 is satisfied), the processing ends. After a predetermined control cycle elapses, the above processing is repeated.

[0130] FIG. 10 is a timing chart illustrating an example of the operation of the propulsion system.

[0131] In FIG. 1, “0” indicates that a determination result in the controller 8 is “No”, and “1” indicates that the determination result in the controller 8 is “Yes” in each a “boat speed determination flag”, a “straight advancing determination flag”, and a “heel control conducting determination flag”.

[0132] As illustrated in FIG. 10, for example, when the boat speed V is increased in accordance with the operation by the boat operator on the thrust inputter 72 and exceeds the second threshold V2 (time t1), the boat speed determination flag of the controller 8 in the above step S142 changes from “0” to “1”. In the example of FIG. 10, at this timing, the straight advancing determination flag in the above step S149 is “1”, and it is determined that the boat 1 is in a straight advancing state in accordance with the actual steering angle detected by the actual steering angle sensor 67, based on the steering angle of the steering angle inputter 71. Therefore, the heel control conducting determination flag is “1”, and the heel control (and the trim support control) is conducted.

[0133] Then, when the boat speed V is decreased in accordance with the operation by the boat operator on the thrust inputter 72, and becomes equal to or lower than the third threshold V3 (time t2), the boat speed determination flag in the above step S142 changes from “1” to “0”. Also at this timing, the straight advancing determination flag is “1” in accordance with the steering angle of the steering angle inputter 71, but the heel control conducting determination flag is “0”, and the heel control is stopped.

[0134] Subsequently, when the actual steering angle in the right direction starts to increase in accordance with the steering operation by the boat operator on the steering angle inputter 71 (time t3), the straight advancing determination flag remains “1”. Furthermore, when the actual steering angle changes to the right direction in accordance with the steering operation by the boat operator on the steering angle inputter 71 and the actual steering angle in the right direction is equal to or larger than a predetermined rightward steering angle threshold (outbound) (time t4), the straight advancing determination flag changes from “1” to “0”. At this timing, the boat speed V is lower than the second threshold V2. Thus, the boat speed determination flag remains at “0”, and the heel control conducting determination flag also remains at “0”.

[0135] Next, when the actual steering angle in the right direction is smaller than the rightward steering angle threshold (return) (time t5) in accordance with the steering operation by the boat operator on the steering angle inputter 71, the straight advancing determination flag changes from “0” to “1”. Furthermore, when the actual steering angle is switched from the right direction to the left direction in accordance with the steering operation by the boat operator on the steering angle inputter 71 and the actual steering angle in the left direction is equal to or larger than the leftward steering angle threshold (outbound) (time t6), the straight advancing determination flag returns from “1” to “0”. At this timing, the boat speed V is lower than the second threshold V2. Thus, the boat speed determination flag remains at “0”, and the heel control conducting determination flag also remains at “0”.

[0136] Then, when the actual steering angle in the left direction is smaller than the leftward steering angle threshold (return) (time t7) in accordance with the steering operation by the boat operator on the steering angle inputter 71, the straight advancing determination flag changes from “0” to “1”.

[0137] Then, when the boat speed V is increased in accordance with the operation by the boat operator on the thrust inputter 72 and exceeds the second threshold V2 (time t8), the boat speed determination flag changes from “0” to “1”. Thus, the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the second threshold V2. Thus, the heel control conducting determination flag changes from “0” to “1”, and the heel control (and the trim support control) is conducted.

[0138] In this manner, in a case where the preset condition is satisfied, the propulsion system 20 according to the present embodiment conducts the heel control in addition to the trim support control, and causes the trim angle adjuster 45 to adjust the trim angle to the heel suppression angle θd set with reference to the trim support angle of the propulsion machine 3. Accordingly, in the case where the preset condition is satisfied, the heel control is conducted in addition to the trim support control, and thus it becomes possible to suppress the heel angle θh of the boat 1 while automatically adjusting the trim angle. Therefore, it becomes possible to smoothly conduct the heel control and the trim support control in accordance with the navigation state of the boat 1, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0139] In addition, the propulsion system 20 according to the present embodiment enables conducting the heel control in a case where it is determined that the boat 1 is advancing straight, based on the input value of the steering angle. Thus, as the preset condition, in the case where the boat 1 is advancing straight, it becomes possible to smoothly conduct the heel control, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0140] In addition, the propulsion system 20 according to the present embodiment conducts the heel control in the case where the heel angle θh is equal to or larger than the preset heel angle reference value θhs. Thus, as the preset conditions, while the boat 1 is advancing straight and in the case where the heel angle θh is large, it becomes possible to suppress the heel angle θh, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat 1 can be improved.

[0141] In addition, the propulsion system 20 according to the present embodiment stops conducting the trim support control and the heel control, in a case where it is determined that the boat 1 is turning, based on the input value of the steering angle. Thus, while the boat 1 is turning, it becomes possible to suppress inhibition of the turning property due to the heel control or the trim support control.

[0142] Further, the propulsion system 20 according to the present embodiment conducts the hump control when the boat speed V becomes equal to or higher than the preset first threshold V1. Thus, as a preset condition, in a case where the boat speed V is equal to or higher than the first threshold V1 and the bow is in a state of easily lifted with respect to the stern of the boat 1, the trim angle is automatically adjusted by conducting the hump control, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat 1 can be improved.

[0143] Further, while conducting the heel control, the propulsion system 20 according to the present embodiment stops conducting the heel control upon receipt of the operation input from the trim angle operation unit 73. Thus, when the trim angle is manually operated by the boat operator of the boat 1, conducting the heel control is stopped, so that an uneasy feeling of the boat operator who has operated the trim angle can be suppressed.

[0144] In addition, in a state in which the heel control is stopped upon receipt of the operation input from the trim angle operation unit 73, and in a case where a preset return condition is satisfied, the propulsion system 20 according to the present embodiment enables conducting the heel control. Thus, after the trim angle is manually operated by the boat operator of the boat 1 and conducting the heel control is stopped, in a case where a preset return condition is satisfied, it becomes possible to transition the state to the standby state that enables conducting the heel control.

[0145] In addition, in conducting the trim support control, the propulsion system 20 according to the present embodiment sets the trim support angles of the propulsion machines 3 on both sides in the left-right direction to the same value. Thus, the trim angle can be effectively adjusted in the boat 1 in the straight advancing state.

[0146] Further, in a case of conducting the heel control, the propulsion system 20 according to the present embodiment sets the heel suppression angle θd of the propulsion machine 3 on one side in the left-right direction to a value larger than the trim support angle, and also sets the heel suppression angle θd of the propulsion machine 3 on the other side in the left-right direction to a value smaller than the trim support angle. Thus, in a case where the heel angle θh of the boat 1 is large, the heel angle θh can be suppressed satisfactorily.

[0147] In addition, the propulsion system 20 according to the present embodiment includes the intermediate member 37 between the hull 2 and the propulsion machine 3 to increase the inclination angle of the propulsion machine 3 rearward in the propulsion direction. Thus, it becomes possible to further largely incline the propulsion machine 3 rearward in the propulsion direction of the boat 1, so that the trim angle can be made larger in the negative direction. Therefore, in a case where the heel angle θh of the boat 1 is large, the heel angle θh can be more effectively suppressed.

[0148] Note that the present invention is not limited to the above-described embodiments with reference to the drawings, and various modifications are conceivable within the technical scope.

[0149] For example, in the above embodiment, the trim support control, the heel control, and the like are conducted, based on the boat speed V. However, the trim support control, the heel control, and the like may be conducted, based on the rotation speed of the propulsion machine 3 instead of the boat speed V.

[0150] In addition, in the above embodiment, while the boat 1 is advancing straight, the case where only the trim support control is conducted and the case where the trim support control and the heel control are both conducted in accordance with the boat speed V have been given as examples. However, while the boat 1 is advancing straight, it is also possible to conduct only the heel control in accordance with the boat speed V, such as a case where the boat operator cancels the trim support control in setting.

[0151] Further, in the above-described embodiment, the trim support control, the heel control, and the like are conducted, based on the actual steering angle detected by the actual steering angle sensor 67. However, the trim support control, the heel control, and the like may be conducted, based on the steering instruction angle of the steering angle inputter 71.

[0152] In the above embodiment, one propulsion machine 3 is provided on each of both left and right sides, but a plurality of propulsion machines 3 may be provided on each of both left and right sides.

[0153] In addition, the procedure and contents of the control conducted by the controller 8 can be changed as appropriate.

[0154] Then, the constitution in the above embodiment is an example of the present invention, and various changes can be made without departing from the gist of the present invention.

[0155] While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.REFERENCE SIGNS LIST1 Boat

[0157] 2 Hull

[0158] 3 Propulsion Machine

[0159] 3a Right propulsion machine

[0160] 3b Left propulsion machine

[0161] 6 Detector

[0162] 7 Operation unit

[0163] 8 Controller

[0164] 20 Propulsion system

[0165] 32 Drive source

[0166] 34 Propulsor

[0167] 36 Steering shaft

[0168] 37 Intermediate member

[0169] 45 Trim angle adjuster

[0170] 63 Steering angle sensor (steering angle detector)

[0171] 71 Steering angle inputter

Examples

Embodiment Construction

[0037]Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that it is assumed that front, rear, upper, lower, left, and right directions in the following description respectively coincide with the directions of a boat 1. In this case, an arrow FR in the drawing indicates a forward side of the boat 1, an arrow UP in the drawing indicates an upper side of the boat 1, and an arrow LH in the drawing indicates a leftward side of the boat 1. In addition, a center line CL indicates the center position of the boat 1 in a left-right direction (a width direction).

[0038]FIG. 1 is a plan view of the boat according to an embodiment. FIG. 2 is a functional block diagram of a propulsion system of the boat.

[0039]As illustrated in FIG. 1, the boat 1 includes: a hull 2; and a propulsion system 20, which is provided on the hull 2.

[0040]As illustrated in FIGS. 1 and 2, the propulsion system 20 includes a plurality of propulsion machines 3, an operatio...

CROSS-REFERENCE TO RELATED APPLICATION

[0001] Priority is claimed on Japanese Patent Application No. 2025-057486, filed Mar. 31, 2025, the content of which is incorporated herein by reference.BACKGROUND OF THE INVENTIONField of the Invention

[0002] The present invention relates to a propulsion system of a boat.Description of Related Art

[0003] Various techniques for automatically controlling a propulsion system of a boat have been conventionally proposed in order to improve stability, acceleration, a maximum speed, energy efficiency, and the like, in navigating the boat.

[0004] For example, Japanese Patent No. 5059392 discloses a constitution related to heel control of controlling a heel angle of a boat. In this constitution, in a case where it is determined that the boat is not turning in accordance with the steering angle of the steering mechanism of the boat, the heel angle of the boat is increased in a direction corresponding to the steering angle of the steering mechanism by generating a difference between the left lift force and right lift force of the boat.SUMMARY OF THE INVENTION

[0005] In the boat, by the way, not only the heel control but also another type of control is conducted in accordance with a navigation state of the boat in some cases. For example, at the time of accelerating or cruising, trim support control of adjusting a trim angle to an optimum position in accordance with the boat speed or the rotation speed of the propulsion machine is conducted in some cases.

[0006] Such heel control and trim support control can be conducted individually, or can be conducted simultaneously. Hence, there is a demand for smoothly conducting the heel control and the trim support control in accordance with the navigation state of the boat to improve the stability, the acceleration, the maximum speed, the energy efficiency, and the like.

[0007] The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a propulsion system of a boat capable of smoothly conducting heel control and trim support control in accordance with a navigation state of the boat to improve stability, acceleration, a maximum speed, energy efficiency, and the like.

[0008] In order to solve the above problems, the present disclosure adopts the following aspects.

[0009] (1) A propulsion system of a boat according to one aspect of the present disclosure, includes: at least one propulsion machine including a drive source, and a propulsor configured to generate thrust with dynamic power transmitted from the drive source, the at least one propulsion machine being provided on each of both sides in a left-right direction with respect to a center of a hull; a trim angle adjuster configured to adjust a trim angle of each of the propulsion machines on the both sides in the left-right direction with respect to the hull; and a controller configured to control the trim angle adjuster, in which the controller is capable of conducting trim support control and heel control, the trim support control causing the trim angle adjuster to adjust the trim angle to a trim support angle set in accordance with either a preset boat speed or a rotation speed of a propulsion machine, the heel control causing the trim angle adjuster to adjust the trim angle to a heel suppression angle set in accordance with an inclination in a roll direction of the hull to suppress the inclination in the roll direction of the hull, and in a case where a preset condition is satisfied, the controller conducts the heel control in addition to the trim support control, and causes the trim angle adjuster to adjust the trim angle to the heel suppression angle set with reference to the trim support angle of the propulsion machine.

[0010] (2) The propulsion system of the boat according to the above aspect (1) may further include a heel angle detector configured to detect a heel angle corresponding to an inclination in a roll direction of the hull, in which in a case where the heel angle is equal to or larger than a preset heel angle reference value, the controller may conduct the heel control.

[0011] (3) The propulsion system of the boat according to the above aspect (1) or (2) may further include a steering angle detector configured to detect a steering angle around a steering shaft of the propulsion machine with respect to the hull, in which in a case where it is determined that the boat is advancing straight, based on a detection value of a steering angle detected by the steering angle detector, the controller may enable conducting the heel control.

[0012] (4) In the propulsion system of the boat according to the above aspect (3), in a case where it is determined that the boat is turning, based on a detection value of the steering angle of the steering angle detector, the controller may stop conducting the trim support control and the heel control.

[0013] (5) The propulsion system of the boat according to one of the above aspects (1) to (4) may further include a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, in which while conducting the trim support control and the heel control, upon receipt of an operation input from the trim angle operation unit, the controller may stop conducting the heel control.

[0014] (6) In the propulsion system of the boat according to the above aspect (5), in a state in which the operation input from the trim angle operation unit is received and conducting the heel control is stopped, and in a case where a preset return condition is satisfied, the controller may enable conducting the heel control.

[0015] (7) In the propulsion system of the boat according to one of the above aspects (1) to (6), in conducting the trim support control, the controller may set the trim support angles of the propulsion machines on the both sides in the left-right direction to an identical value.

[0016] (8) In the propulsion system of the boat according to one of the above aspects (1) to (7), in conducting the heel control, the controller may set the heel suppression angle of the propulsion machine on one side in the left-right direction to a value larger than the trim support angle, and may also set the heel suppression angle of the propulsion machine on the other side in the left-right direction to a value smaller than the trim support angle.

[0017] (9) The propulsion system of the boat according to one of the above aspects (1) to (8) may further include an intermediate member provided between the hull and the propulsion machine, the intermediate member increasing a rearward inclination angle in a propulsion direction of the propulsion machine.

[0018] According to the aspect (1), in a case where the preset condition is satisfied, the heel control is conducted in addition to the trim support control, and the trim angle adjuster is caused to adjust the trim angle to the heel suppression angle set with reference to the trim support angle of the propulsion machine. Accordingly, in the case where the preset condition is satisfied, the heel control is conducted in addition to the trim support control, and thus it becomes possible to suppress the heel angle of the boat while automatically adjusting the trim angle. Therefore, it becomes possible to smoothly conduct the heel control and the trim support control in accordance with the navigation state of the boat, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0019] According to the aspect (2), the heel control is conducted when the heel angle is equal to or larger than the preset heel angle reference value. Thus, as the preset conditions, while the boat is advancing straight and in the case where the heel angle is large, it becomes possible to suppress the heel angle, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat can be improved.

[0020] According to the aspect (3), conducting the heel control is enabled when it is determined that the boat is advancing straight, based on the detection value of the steering angle. Thus, as the preset condition, while the boat is advancing straight, it becomes possible to smoothly conduct the heel control, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0021] According to the aspect (4), in a case where it is determined that the boat is turning, based on the detection value of the steering angle, conducting the trim support control and the heel control is stopped. Thus, while the boat is turning, it becomes possible to suppress inhibition of the turning property due to the heel control or the trim support control.

[0022] According to the aspect (5), while conducting the heel control, upon receipt of the operation input from the trim angle operation unit, conducting the heel control is stopped. Thus, when the trim angle is manually operated by the boat operator of the boat, conducting the heel control is stopped, so that an uneasy feeling of the boat operator who has operated the trim angle can be suppressed.

[0023] According to the aspect (6), in a state in which the heel control is stopped upon receipt of the operation input from the trim angle operation unit, and in a case where a preset return condition is satisfied, conducting the heel control is enabled. Thus, after the trim angle is manually operated by the boat operator of the boat and conducting the heel control is stopped, in a case where a preset return condition is satisfied, it becomes possible to transition the state to the standby state that enables conducting the heel control.

[0024] According to the aspect (7), in conducting the trim support control, the trim support angles of the propulsion machines on both sides in the left-right direction are set to the same value. Thus, the trim angle can be effectively adjusted in the boat in the straight advancing state.

[0025] According to the aspect (8), in conducting the heel control, the heel suppression angle of the propulsion machine on one side in the left-right direction is set to a value larger than the trim support angle, and the heel suppression angle of the propulsion machine on the other side in the left-right direction is also set to a value smaller than the trim support angle. Thus, in a case where the heel angle of the boat is large, the heel angle can be suppressed satisfactorily.

[0026] According to the aspect (9), an intermediate member for increasing the inclination angle of the propulsion machine rearward in the propulsion direction is provided between the hull and the propulsion machine. Thus, it becomes possible to further largely incline the propulsion machine rearward in the propulsion direction of the boat, so that the trim angle can be made larger in the negative direction. Therefore, in a case where the heel angle of the boat is large, the heel angle can be more effectively suppressed.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a plan view of a boat according to an embodiment;

[0028] FIG. 2 is a functional block diagram of a propulsion system of the above boat;

[0029] FIG. 3 is a side view of a propulsion machine of the above propulsion system;

[0030] FIG. 4 is a diagram illustrating an example of trim support control, heel control, hump control, and bogen control to be conducted in accordance with a boat speed in the above propulsion system;

[0031] FIG. 5 is a diagram illustrating an example of a set value of a trim support angle in the trim support control, the heel control, and the hump control to be conducted in accordance with the boat speed in above the propulsion system;

[0032] FIG. 6 is a view illustrating a state in which the trim support control is being conducted in the above propulsion system;

[0033] FIG. 7 is a view illustrating a state of conducting the heel control in a state in which the above boat is inclined to a port side;

[0034] FIG. 8 is a view illustrating a state of conducting the heel control in a state in which the above boat is inclined to a starboard side;

[0035] FIG. 9 is a flowchart illustrating a method for conducting the heel control while conducting the trim support control; and

[0036] FIG. 10 is a timing chart illustrating an example of the operation of the above propulsion system.DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that it is assumed that front, rear, upper, lower, left, and right directions in the following description respectively coincide with the directions of a boat 1. In this case, an arrow FR in the drawing indicates a forward side of the boat 1, an arrow UP in the drawing indicates an upper side of the boat 1, and an arrow LH in the drawing indicates a leftward side of the boat 1. In addition, a center line CL indicates the center position of the boat 1 in a left-right direction (a width direction).

[0038] FIG. 1 is a plan view of the boat according to an embodiment. FIG. 2 is a functional block diagram of a propulsion system of the boat.

[0039] As illustrated in FIG. 1, the boat 1 includes: a hull 2; and a propulsion system 20, which is provided on the hull 2.

[0040] As illustrated in FIGS. 1 and 2, the propulsion system 20 includes a plurality of propulsion machines 3, an operation unit 7, a detector 6 (see FIG. 2), and a controller 8 (see FIG. 2).Propulsion Machine

[0041] As illustrated in FIG. 1, the propulsion machine 3 includes: a right propulsion machine 3a, which is provided on the right of a stern 2b with respect to the center line CL; and a left propulsion machine 3b, which is provided on the left of the stern 2b, with respect to the center line CL. The two propulsion machines 3 (the right propulsion machine 3a and the left propulsion machine 3b) are provided on the stern 2b of the hull 2 respectively on both right and left sides of the stern 2b, interposing the center line CL between them. That is, the boat 1 in the present embodiment is a so-called small-sized boat in which the two propulsion machines are provided. Hereinafter, in a case where it is not necessary to distinguish between the propulsion machines 3a and 3b, they will be collectively described as the propulsion machine 3.

[0042] FIG. 3 is a side view of a propulsion machine of the propulsion system.

[0043] As illustrated in FIG. 3, the propulsion machine 3 is, for example, an outboard motor. The propulsion machine 3 includes: a casing 31; a drive source 32; a drive shaft 33; a propulsor 34; and a shift switching mechanism 35.

[0044] The casing 31 is attached to a bracket 22, which is provided on the stern 2b, via a steering shaft (a swivel shaft) 36, which extends in an up-down direction. The propulsion machine 3 is attached to the hull 2 so as to be rotatable around the steering shaft 36 in accordance with the operation of a steering actuator 41 (see FIG. 2).

[0045] The drive source 32 is, for example, an internal combustion engine such as an engine. The drive source 32 is accommodated in an upper portion of the casing 31 with a crankshaft extending in the up-down direction. Dynamic power (an engine speed) of the drive source 32 is set, based on an opening degree of a throttle valve. The throttle valve is driven by the operation of a throttle actuator 42 (see FIG. 2). Note that the drive source 32 may be an electric motor.

[0046] The drive shaft 33 transmits the dynamic power generated by the drive source 32 to the propulsor 34 via the shift switching mechanism 35. The drive shaft 33 extends in the up-down direction in the casing 31. An upper end portion of the drive shaft 33 is connected with the drive source 32.

[0047] The propulsor 34 includes a propeller shaft 341 and propellers 342.

[0048] The propeller shaft 341 is provided at a lower end portion of the casing 31 so as to be rotatable around an axis along a front-rear direction. A front end portion of the propeller shaft 341 is connected with the shift switching mechanism 35 in the casing 31.

[0049] The propellers 342 are provided projecting outside of the casing 31 at a rear end portion of the propeller shaft 341. The propellers 342 rotate integrally with the propeller shaft 341.

[0050] The shift switching mechanism 35 includes a drive gear 351, a forward gear 352, a reverse gear 353, and a clutch 354.

[0051] The drive gear 351 is provided at a lower end portion of the drive shaft 33. The drive gear 351 is rotatable integrally with the drive shaft 33.

[0052] The forward gear 352 and the reverse gear 353 are rotatably provided at positions facing each other in the front-rear direction, interposing the drive gear 351 between them on the propeller shaft 341. The forward gear 352 and the reverse gear 353 are capable of meshing with the drive gear 351. The forward gear 352 and the reverse gear 353 rotate in opposite directions to each other in accordance with the rotation of the drive gear 351.

[0053] The clutch 354 switches between a connection state and a disconnection state of the dynamic power between either the forward gear 352 or the reverse gear 353 and the propeller shaft 341. The clutch 354 is provided to be rotatable integrally with the propeller shaft 341. The clutch 354 is provided to be movable in the front-rear direction along the propeller shaft 341 in accordance with the operation of a shift actuator 43. The clutch 354 alternatively meshes with the forward gear 352 and the reverse gear 353 to switch the rotation directions of the propeller shaft 341 and the propellers 342, and is capable of switching the propulsion direction of the boat 1.

[0054] The propulsion machine 3 is supported by the bracket 22, which is attached to the stern 2b of the hull 2, so as to be rotatable around a support shaft 38, which extends in the left-right direction. This enables the propulsion machine 3 to be rotatable (swingable) around the support shaft 38 with respect to a reference plane Fv. Here, the reference plane Fv denotes a virtual plane along a vertical plane that passes through the center axis of the support shaft 38 when the hull 2 is simply floated on the water surface.

[0055] Here, a trim angle θt is defined as an angle at which the direction in which the steering shaft 36 of the propulsion machine 3 extends is inclined in the front-rear direction around the support shaft 38 with respect to the reference plane Fv. In the present embodiment, with regard to the trim angle θt, a positive (plus) direction represents a direction in which a lower end portion of the propulsion machine 3 is apart rearward from the stern 2b, and a negative (minus) direction represents a direction in which the lower end portion of the propulsion machine 3 approaches the stern 2b.

[0056] The trim angle θt of the propulsion machine 3 is adjustable by a trim angle adjuster 45. The trim angle adjuster 45 uses an actuator, not illustrated, to rotate the propulsion machine 3 around the support shaft 38 within a preset angle range. The rotation of the propulsion machine 3 in the positive direction and the negative direction is restricted by hitting a stopper, not illustrated, or the like provided on the bracket 22.

[0057] In the present embodiment, the bracket 22 is attached to an attachment surface 2f, which is formed on the stern 2b, via an intermediate member 37. The intermediate member 37 is sandwiched between the bracket 22 and the attachment surface 2f. The intermediate member 37 is formed in a wedge shape having a thickness in the front-rear direction gradually decreasing from the top to the bottom. Thus, the bracket 22 is provided to be further inclined rearward than a case of being directly attached to the attachment surface 2f without the use of the intermediate member 37. This constitution enables setting of a larger rotation angle (rotation range) of the propulsion machine 3 in the negative direction.Operation Unit

[0058] As illustrated in FIGS. 1 and 2, the operation unit 7 is provided to allow a boat operator to perform an operation input in order to navigate the boat 1. In the present embodiment, the operation unit 7 includes, for example, a steering angle inputter 71, a thrust inputter 72, a trim angle operation unit 73, and an operation inputter 74.

[0059] The steering angle inputter 71 is provided in a cockpit of the hull 2. The steering angle inputter 71 is, for example, a steering wheel provided to be rotatable clockwise and counterclockwise. The steering angle inputter 71 receives an operation input by the boat operator from the outside, in changing the course of the boat 1 (the hull 2). That is, the steering angle inputter 71 receives an operation, by the boat operator, for changing the direction (the steering angle) of the propulsion machine 3 around the steering shaft 36. The steering angle denotes an inclination angle of the propulsion machine 3 with respect to the center line CL in a plan view. In the present embodiment, the steering angle of the propulsion machine 3 when the course of the boat 1 is the straight advancing direction is set as the reference value (0 degrees). Note that as the steering angle inputter 71, in addition to the steering wheel, a joystick may be used, and the steering angle inputter 71 may be mounted as a switch or the like of the operation inputter 74.

[0060] The thrust inputter 72 is provided in the cockpit of the hull 2. The thrust inputter 72 is, for example, a throttle lever. In changing the thrust of the propulsion machine 3 or the shift position of the propulsion machine 3, the thrust inputter 72 receives an operation input from the outside by the boat operator. The thrust inputter 72 is constituted to be capable of reciprocating in accordance with rotation, sliding, or the like. The thrust inputter 72 is capable of reciprocating within an operation region in which three shift regions of the forward position F, the neutral position N, and the reverse position R are aligned. When the thrust inputter 72 is located at the forward position F, the propulsion machine 3 exerts thrust for moving the boat 1 forward. When the thrust inputter 72 is located at the reverse position R, the propulsion machine 3 exerts thrust for moving the boat 1 rearward. When the thrust inputter 72 is located at the neutral position N, the drive gear 351, which is illustrated in FIG. 3, is disconnected from the forward gear 352 and the reverse gear 353, and the propulsion machine 3 does not exert thrust for propelling the boat 1.

[0061] As illustrated in FIG. 1, a trim angle operation switch is provided as the trim angle operation unit 73 in the vicinity of the thrust inputter 72. The boat operator of the boat 1 is able to change the trim angle θt of the propulsion machine 3 by manually operating the trim angle operation switch (the trim angle operation unit 73).

[0062] The operation inputter 74 receives various operations on the boat 1. The operation inputter 74 is constituted to be manually operable by the boat operator, such as a multi-function display (MFD). Note that the operation inputter 74 may be an external device such as a mobile terminal connected to the boat 1 in a wired or wireless manner.Detector

[0063] The detector 6 illustrated in FIG. 2 detects a state (a navigation state) of the boat 1. In the present embodiment, the detector 6 includes a position sensor 61, a boat speed sensor 62, a steering angle sensor (a steering angle detector) 63, an inertial sensor 64, a trim operation sensor 65, a trim angle sensor 66, and an actual steering angle sensor 67.

[0064] The position sensor 61 detects the position of the thrust inputter 72. The position sensor 61 outputs, to the controller 8, a detection signal based on the position of the thrust inputter 72.

[0065] As illustrated in FIG. 2, the boat speed sensor 62 detects a boat speed V of the boat 1. The boat speed sensor 62 is, for example, a global positioning system (GPS) or the like, and calculates the boat speed V, based on a positioning signal from a positioning satellite. Note that the boat speed sensor 62 may be an acoustic sensor or an electromagnetic sensor that detects the boat speed (a boat speed relative to the water) V of the boat 1. The boat speed sensor 62 may estimate the boat speed V, based on the engine speed. The boat speed sensor 62 outputs a signal indicating the detected boat speed V to the controller 8.

[0066] The steering angle sensor 63 detects an operation amount (a steering instruction angle) in accordance with the rotation operation on the steering angle inputter 71. The steering angle sensor 63 outputs, to the controller 8, a detection signal based on the steering instruction angle on the steering angle inputter 71.

[0067] The inertial sensor 64 detects the inclination in the roll direction of the hull 2, that is, a heel angle θh. The inertial sensor 64 is also capable of detecting an inclination or the like in the pitch direction of the hull 2. The inertial sensor 64 outputs, to the controller 8, detection signals based on the detected inclinations in the roll direction and the pitch direction of the hull 2.

[0068] The trim operation sensor 65 detects whether an operation input has been made on the trim angle operation switch, which serves as the trim angle operation unit 73. The trim operation sensor 65 outputs, to the controller 8, a detection signal indicating the presence or absence of the detected operation input.

[0069] The trim angle sensor 66 is provided in the trim angle adjuster 45. The trim angle sensor 66 detects an actual trim angle θt to be adjusted by the trim angle adjuster 45. The trim angle sensor 66 outputs, to the controller 8, a detection signal indicating the detected trim angle θt.

[0070] The actual steering angle sensor 67 is provided on the steering actuator 41. The actual steering angle sensor 67 detects the actual steering angle of the propulsion machine 3, and outputs the actual steering angle to the controller 8.Controller

[0071] The controller 8 integrally controls the operation of the boat 1 (the propulsion machine 3). The controller 8 is an integrated electronic control device or a plurality of electronic control devices included in the boat 1. The controller 8 is implemented by, for example, a hardware processor such as a central processing unit (CPU) executing a program (software) stored in a storage 80 such as a read only memory (ROM), a random access memory (RAM), or the like. Some or all of these constituent elements may be implemented by a hardware (a circuit part; including circuitry) such as a large scale integration (LSI), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a graphics processing unit (GPU), or system on chip (SOC), or may be implemented by software and hardware in cooperation.

[0072] The controller 8 includes a storage 80, an acquisitor 81, a determiner 82, and a drive processor 83.

[0073] The storage 80 records programs, various data, and the like necessary for navigation of the boat 1, such as the trim support control, the heel control, the hump control, and the bogen control.

[0074] The acquisitor 81 acquires detection results of various sensors of the detector 6.

[0075] The determiner 82 determines the state of the boat 1, based on information obtained by the acquisitor 81 and information stored in the storage 80.

[0076] The drive processor 83 controls operations of various actuators, based on a determination result by the determiner 82 and the information stored in the storage 80 or the acquisitor 81. In the present embodiment, in a case where the determiner 82 determines that a predetermined condition is satisfied, the drive processor 83 controls the operations of the trim angle adjuster 45, the steering actuator 41, and the like to conduct the trim support control, the heel control, the hump control, and the bogen control. In the present embodiment, when the boat 1 is in a straight advancing state, the drive processor 83 conducts the trim support control, the heel control, the hump control, and the bogen control. In the present embodiment, the drive processor 83 does not conduct the bogen control, when the boat 1 is not in the straight advancing state.Trim Support Control

[0077] FIG. 4 is a diagram illustrating an example of the trim support control, the heel control, the hump control, and the bogen control to be conducted in accordance with the boat speed in the propulsion system.

[0078] As illustrated in FIG. 4, when the boat 1 is in the straight advancing state, the drive processor 83 conducts the trim support control in the regions of the heel control, the hump control, and the bogen control in accordance with settings by the boat operator to be input from the trim angle operation unit 73 and the operation inputter 74, for example.

[0079] FIG. 5 is a diagram illustrating an example of set values of the trim support angles in the trim support control, the heel control, and the hump control to be conducted in accordance with the boat speed in the propulsion system.

[0080] As illustrated in FIG. 5, in the trim support control, the trim angle adjuster 45 is caused to adjust a trim angle θt to be a trim support angle θsp, which is set in accordance with a preset boat speed V (or rotation speed of the propulsion machine). In the present embodiment, in the trim support control, the trim support angle θsp is set in accordance with the boat speed V to optimize stability, acceleration, a maximum speed, energy efficiency, and the like. The trim support angle θsp may be set in accordance with the rotation speed of the propulsion machine. Therefore, in the storage 80, the boat speed V (or the rotation speed of the propulsion machine) and the trim support angle θsp, at which the stability, the acceleration, the maximum speed, the energy efficiency, and the like are optimized, are stored beforehand in association with each other. In the example of FIG. 5, the trim support angle θsp is set in a stepwise manner with respect to the boat speed V (or the rotation speed of the propulsion machine).

[0081] The drive processor 83 acquires, from the storage 80, the trim support angle θsp, which is associated with the boat speed acquired by the acquisitor 81.

[0082] The drive processor 83 controls the trim angle adjuster 45 so that the trim angle θt of the propulsion machine 3 approaches the acquired trim support angle θsp.

[0083] FIG. 6 is a view illustrating a state in which the trim support control is being conducted in the propulsion system.

[0084] As illustrated in FIG. 6, in conducting the trim support control, the drive processor 83 sets the trim support angles θsp of the propulsion machines 3a and 3b on both sides in the left-right direction to the same value.Heel Control

[0085] As illustrated in FIG. 4, when the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the second threshold V2, while the trim support control is being conducted, and in a case where the determiner 82 determines that a preset condition is satisfied, the drive processor 83 conducts the heel control in addition to the trim support control. Specifically, when the boat 1 is in the straight advancing state, while the trim support control is being conducted, and when the boat speed becomes equal to or higher than the second threshold V2, the drive processor 83 conducts the heel control in addition to the trim support control, that is, both the trim support control and the heel control.

[0086] In this case, the drive processor 83 conducts the heel control, in a case where the heel angle θh, which is detected by the inertial sensor 64, and which is the inclination in the roll direction of the hull 2, is equal to or larger than a preset heel angle reference value θhs (for example, several degrees). That is, in a case where the heel angle θh is smaller than the heel angle reference value θhs, the drive processor 83 continuously conducts the trim support control without conducting the heel control.

[0087] In conducting the heel control, the drive processor 83 sets a heel suppression angle θd as a target value in accordance with the heel angle θh of the hull 2. Here, the heel suppression angle θd denotes a trim angle of the propulsion machines 3 on both sides in the left-right direction for suppressing the inclination in the roll direction of the hull 2. The drive processor 83 calculates a heel suppression angle θd, which is capable of effectively suppressing the inclination in the roll direction of the hull 2, in accordance with the heel angle θh of the hull 2 in a preset calculation formula.

[0088] The drive processor 83 sets the heel suppression angle θd with reference to the trim support angle θsp of the propulsion machine 3 at such a timing. With regard to the trim support angle θsp, the drive processor 83 sets the heel suppression angle θd of the propulsion machine 3 on one side in the left-right direction to a value larger than the trim support angle θsp, and also sets the heel suppression angle θd of the propulsion machine 3 on the other side in the left-right direction to a value smaller than the trim support angle θsp.

[0089] FIG. 7 is a view illustrating a state of conducting the heel control in a state in which the boat is inclined to the port side. FIG. 8 is a view illustrating a state of conducting the heel control in a state in which the boat is inclined to the starboard side.

[0090] For example, as illustrated in FIG. 7, when the hull 2 is inclined to the port side, the drive processor 83 sets a heel suppression angle θd2 of the right propulsion machine 3a to a value larger than the trim support angle θsp, and sets a heel suppression angle θd1 of the left propulsion machine 3b to a value smaller than the trim support angle θsp. For example, as illustrated in FIG. 8, when the hull 2 is inclined to the starboard side, the drive processor 83 sets the heel suppression angle θd1 of the left propulsion machine 3b to a value larger than the trim support angle θsp, and sets the heel suppression angle θd2 of the right propulsion machine 3a to a value smaller than the trim support angle θsp.

[0091] The drive processor 83 calculates the heel suppression angles θd1 and θd2 with reference to the trim support angle θsp set at such a timing, based on the heel angle θh of the hull 2 at such a timing that has been acquired by the acquisitor 81. The drive processor 83 calculates, in a preset calculation formula, a trim angle addition value Δθt1 to be added to the trim support angle θsp as a reference for the propulsion machine 3 on one side in the left-right direction and a trim angle subtraction value Δθt2 to be subtracted from the trim support angle θsp as a reference for the propulsion machine 3 on the other side in the left-right direction. Here, the absolute value of the trim angle addition value Δθt1 and the absolute value of the trim angle subtraction value Δθt2 are preferably identical to each other.

[0092] When the hull 2 is inclined to the port side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the following equation (1), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the following equation (2).θ⁢d⁢1=θ⁢sp-Δ⁢θ⁢t⁢2(1)θ⁢d⁢2=θ⁢sp+Δθ⁢t⁢1(2)

[0093] When the hull 2 is inclined to the starboard side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the following equation (3), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the following equation (4).θ⁢d⁢1=θ⁢sp+Δ⁢θ⁢t⁢1(3)θ⁢d⁢2=θ⁢sp-Δθ⁢t⁢2(4)

[0094] The drive processor 83 sets the heel suppression angles θd1 and θd2 that have been calculated to the target values, and causes the trim angle adjuster 45 to adjust the trim angles θt of the propulsion machines 3 (3a, 3b) so as to approach the heel suppression angles θd1 and θd2.

[0095] While conducting the heel control, in a case where the determiner 82 determines that the boat speed V becomes equal to or lower than a preset third threshold V3, the drive processor 83 stops conducting the heel control. Here, the third threshold V3 is set to be lower than the second threshold V2.

[0096] In addition, while conducting the heel control, in a case where the steering angle sensor 63 receives the input of the steering angle from the steering angle inputter 71, the determiner 82 determines whether the boat 1 is turning, based on a detection value of the propulsion machine 3 by the actual steering angle sensor 67. In a case where it is determined that the boat 1 is turning, the drive processor 83 stops conducting the trim support control and the heel control.

[0097] In addition, while conducting the heel control, in a case where the determiner 82 determines that the operation input by the boat operator is received from the trim angle operation unit 73, the drive processor 83 stops conducting the heel control.Hump Control

[0098] In addition, as illustrated in FIG. 4, when the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the first threshold V1, and in a case where the determiner 82 determines that a preset condition is satisfied, the drive processor 83 conducts the hump control.

[0099] The hump control is conducted to suppress excessive lifting of a bow 2a when the bow 2a is largely lifted with respect to the stern 2b. In conducting the hump control, the drive processor 83 sets the trim angles θt of the propulsion machines 3a and 3b on both sides in the left-right direction to the same value.Bogen Control

[0100] In addition, in a case where the boat speed V is lower than the first threshold V1, the drive processor 83 conducts the bogen control. In the bogen control, the plurality of propulsion machines 3 are steered in a direction intersecting the front-rear direction of the hull 2 in a yaw direction. When the boat 1 is in the straight advancing state and the boat speed V is lower than the first threshold V1, the left and right propulsion machines 3 are rotated in directions opposite to each other around the swivel axis and at almost the same steering angle in the bogen control. It becomes possible to reduce the forward propulsion force that works on the entirety of the hull 2 and to navigate the hull 2 at a low speed or an extremely low speed in the bogen control, as compared with a case where the propulsion machines 3 are disposed in parallel with the front-rear direction of the hull 2. Note that in the present embodiment, there is no limitation to the specific content of the bogen control.Control Method of Propulsion System

[0101] Next, an operation method of the propulsion system will be described. Processing to be described below is repeatedly performed, for example, at a predetermined control cycle (for example, several tens of milliseconds).

[0102] Here, the trim support control is conducted at an appropriate timing in accordance with a setting of the boat operator. In the trim support control, the controller 8 sets the trim support angle θsp at which the stability, the acceleration, the maximum speed, the energy efficiency, and the like are optimized as the target value in accordance with the boat speed V acquired in step S11. The controller 8 controls the trim angle adjuster 45 so that the trim angles θt of both the left and right propulsion machines 3 approach the trim support angle θsp, which is set as the target value.

[0103] FIG. 9 is a flowchart illustrating a method for conducting the heel control while conducting the trim support control.

[0104] While conducting the trim support control, the controller 8 causes the acquisitor 81 to acquire a detection result of the boat speed in the boat speed sensor 62 at a predetermined control cycle, in step S141.

[0105] In step S142, the controller 8 determines whether the boat speed V is equal to or higher than the second threshold V2, based on the detection result of the boat speed sensor 62.

[0106] In a case where the determination result in step S142 is “No” (V<V2), the processing ends. The trim support control continues.

[0107] In a case where the determination result in step S142 is “Yes” (V≥V2), the processing proceeds to step S143, and the controller 8 enables conducting the heel control. In other words, the controller 8 sets the heel control to a standby state.

[0108] Next, in step S144, the acquisitor 81 acquires a detection result of the heel angle θh of the hull 2 in the inertial sensor 64.

[0109] In step S145, it is determined whether the heel angle θh is equal to or larger than the heel angle reference value θhs, based on the detection result of the inertial sensor 64.

[0110] In a case where the determination result in step S145 is “No” (θh<θhs), the processing returns to step S144. After a predetermined control cycle elapses, step S144 is repeatedly performed.

[0111] In a case where the determination result in step S145 is “Yes” (θh≥θhs), the processing proceeds to step S146.

[0112] In step S146, the controller 8 conducts the heel control in addition to the trim support control. In step S146, the controller 8 sets the heel suppression angle θd in accordance with the heel angle θh of the hull 2. The controller 8 sets the heel suppression angle θd with reference to the trim support angle θsp of the propulsion machine 3 at such a timing. The drive processor 83 calculates the trim angle addition value Δθt1 to be added to the trim support angle θsp as a reference for the propulsion machine 3 on one side in the left-right direction and the trim angle subtraction value Δθt2 to be subtracted from the trim support angle θsp as a reference for the propulsion machine 3 on the other side in the left-right direction in a preset calculation formula, based on the heel angle θh of the hull 2 at such a timing that has been acquired by the acquisitor 81.

[0113] In a case where the hull 2 is inclined to the port side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the above equation (1), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the above equation (2). In a case where the hull 2 is inclined to the starboard side, the drive processor 83 calculates the heel suppression angle θd1 of the left propulsion machine 3b in the above equation (3), and calculates the heel suppression angle θd2 of the right propulsion machine 3a in the above equation (4).

[0114] The drive processor 83 sets the heel suppression angles θd1 and θd2 that have been calculated to the target values, and causes the trim angle adjuster 45 to adjust the trim angles θt of the propulsion machines 3 (3a and 3b).

[0115] In step S147, while conducting the heel control, it is determined whether a predetermined stop condition for stopping the heel control is satisfied. In the present embodiment, as a predetermined stop condition for stopping the heel control, examples include

[0116] Condition 1: While conducting the heel control, a case where the boat speed V becomes equal to or lower than a preset third threshold V3, and

[0117] Condition 2: A case of receiving an operation input by the boat operator from the trim angle operation unit 73.

[0118] In a case where the determination result in step S147 is “No” (in a case where neither the condition 1 nor the condition 2 is satisfied), the processing proceeds to step S149.

[0119] In a case where the determination result in step S147 is “Yes” (in a case where at least one of the conditions 1 and 2 is satisfied), the processing proceeds to step S148, conducting the heel control is stopped, and only the trim support control is continuously conducted.

[0120] In step S147, upon receipt of the operation input from the trim angle operation unit 73, in a case where conducting the heel control is stopped in step S148, then the determiner 82 determines in step S151 whether a preset return condition is satisfied at every predetermined control cycle. Here, as the return condition, examples include

[0121] Condition 3: A case where the boat speed V changes from outside of the heel control region (equal to or smaller than the third threshold V3) to inside the heel control region (equal to or larger than the second threshold V2), and

[0122] Condition 4: A case where the boat 1 changes from a turning state to a straight advancing state.

[0123] In a case where the determination result in step S151 is “Yes” (in a case where at least one of the conditions 3 and 4 is satisfied), the processing proceeds to step S149.

[0124] In step S149, the controller 8 determines whether the boat 1 is turning. In this case, the controller 8 causes the steering angle sensor 63 to determine whether the boat 1 is turning, based on the input value of the steering angle from the steering angle inputter 71.

[0125] In a case where the determination result in step S149 is “No” (when the boat 1 is not turning, that is, when the boat 1 is advancing straight), the processing ends. After a predetermined control cycle elapses, the above processing is repeatedly performed.

[0126] In a case where the determination result in step S149 is “Yes” (when the boat 1 is turning), the processing proceeds to step S150, and conducting the trim support control and the heel control is stopped.

[0127] In a case where conducting the trim support control and the heel control is stopped in step S150, then the determiner 82 determines in step S152 whether a preset return condition is satisfied at every predetermined control cycle. Here, as the return condition, an example includes

[0128] Condition 5: A case where the boat 1 changes from a turning state to a straight advancing state.

[0129] In a case where the determination result in step S152 is “Yes” (in a case where the condition 5 is satisfied), the processing ends. After a predetermined control cycle elapses, the above processing is repeated.

[0130] FIG. 10 is a timing chart illustrating an example of the operation of the propulsion system.

[0131] In FIG. 1, “0” indicates that a determination result in the controller 8 is “No”, and “1” indicates that the determination result in the controller 8 is “Yes” in each a “boat speed determination flag”, a “straight advancing determination flag”, and a “heel control conducting determination flag”.

[0132] As illustrated in FIG. 10, for example, when the boat speed V is increased in accordance with the operation by the boat operator on the thrust inputter 72 and exceeds the second threshold V2 (time t1), the boat speed determination flag of the controller 8 in the above step S142 changes from “0” to “1”. In the example of FIG. 10, at this timing, the straight advancing determination flag in the above step S149 is “1”, and it is determined that the boat 1 is in a straight advancing state in accordance with the actual steering angle detected by the actual steering angle sensor 67, based on the steering angle of the steering angle inputter 71. Therefore, the heel control conducting determination flag is “1”, and the heel control (and the trim support control) is conducted.

[0133] Then, when the boat speed V is decreased in accordance with the operation by the boat operator on the thrust inputter 72, and becomes equal to or lower than the third threshold V3 (time t2), the boat speed determination flag in the above step S142 changes from “1” to “0”. Also at this timing, the straight advancing determination flag is “1” in accordance with the steering angle of the steering angle inputter 71, but the heel control conducting determination flag is “0”, and the heel control is stopped.

[0134] Subsequently, when the actual steering angle in the right direction starts to increase in accordance with the steering operation by the boat operator on the steering angle inputter 71 (time t3), the straight advancing determination flag remains “1”. Furthermore, when the actual steering angle changes to the right direction in accordance with the steering operation by the boat operator on the steering angle inputter 71 and the actual steering angle in the right direction is equal to or larger than a predetermined rightward steering angle threshold (outbound) (time t4), the straight advancing determination flag changes from “1” to “0”. At this timing, the boat speed V is lower than the second threshold V2. Thus, the boat speed determination flag remains at “0”, and the heel control conducting determination flag also remains at “0”.

[0135] Next, when the actual steering angle in the right direction is smaller than the rightward steering angle threshold (return) (time t5) in accordance with the steering operation by the boat operator on the steering angle inputter 71, the straight advancing determination flag changes from “0” to “1”. Furthermore, when the actual steering angle is switched from the right direction to the left direction in accordance with the steering operation by the boat operator on the steering angle inputter 71 and the actual steering angle in the left direction is equal to or larger than the leftward steering angle threshold (outbound) (time t6), the straight advancing determination flag returns from “1” to “0”. At this timing, the boat speed V is lower than the second threshold V2. Thus, the boat speed determination flag remains at “0”, and the heel control conducting determination flag also remains at “0”.

[0136] Then, when the actual steering angle in the left direction is smaller than the leftward steering angle threshold (return) (time t7) in accordance with the steering operation by the boat operator on the steering angle inputter 71, the straight advancing determination flag changes from “0” to “1”.

[0137] Then, when the boat speed V is increased in accordance with the operation by the boat operator on the thrust inputter 72 and exceeds the second threshold V2 (time t8), the boat speed determination flag changes from “0” to “1”. Thus, the boat 1 is in the straight advancing state and the boat speed V is equal to or higher than the second threshold V2. Thus, the heel control conducting determination flag changes from “0” to “1”, and the heel control (and the trim support control) is conducted.

[0138] In this manner, in a case where the preset condition is satisfied, the propulsion system 20 according to the present embodiment conducts the heel control in addition to the trim support control, and causes the trim angle adjuster 45 to adjust the trim angle to the heel suppression angle θd set with reference to the trim support angle of the propulsion machine 3. Accordingly, in the case where the preset condition is satisfied, the heel control is conducted in addition to the trim support control, and thus it becomes possible to suppress the heel angle θh of the boat 1 while automatically adjusting the trim angle. Therefore, it becomes possible to smoothly conduct the heel control and the trim support control in accordance with the navigation state of the boat 1, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0139] In addition, the propulsion system 20 according to the present embodiment enables conducting the heel control in a case where it is determined that the boat 1 is advancing straight, based on the input value of the steering angle. Thus, as the preset condition, in the case where the boat 1 is advancing straight, it becomes possible to smoothly conduct the heel control, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like can be improved.

[0140] In addition, the propulsion system 20 according to the present embodiment conducts the heel control in the case where the heel angle θh is equal to or larger than the preset heel angle reference value θhs. Thus, as the preset conditions, while the boat 1 is advancing straight and in the case where the heel angle θh is large, it becomes possible to suppress the heel angle θh, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat 1 can be improved.

[0141] In addition, the propulsion system 20 according to the present embodiment stops conducting the trim support control and the heel control, in a case where it is determined that the boat 1 is turning, based on the input value of the steering angle. Thus, while the boat 1 is turning, it becomes possible to suppress inhibition of the turning property due to the heel control or the trim support control.

[0142] Further, the propulsion system 20 according to the present embodiment conducts the hump control when the boat speed V becomes equal to or higher than the preset first threshold V1. Thus, as a preset condition, in a case where the boat speed V is equal to or higher than the first threshold V1 and the bow is in a state of easily lifted with respect to the stern of the boat 1, the trim angle is automatically adjusted by conducting the hump control, so that the stability, the acceleration, the maximum speed, the energy efficiency, and the like of the boat 1 can be improved.

[0143] Further, while conducting the heel control, the propulsion system 20 according to the present embodiment stops conducting the heel control upon receipt of the operation input from the trim angle operation unit 73. Thus, when the trim angle is manually operated by the boat operator of the boat 1, conducting the heel control is stopped, so that an uneasy feeling of the boat operator who has operated the trim angle can be suppressed.

[0144] In addition, in a state in which the heel control is stopped upon receipt of the operation input from the trim angle operation unit 73, and in a case where a preset return condition is satisfied, the propulsion system 20 according to the present embodiment enables conducting the heel control. Thus, after the trim angle is manually operated by the boat operator of the boat 1 and conducting the heel control is stopped, in a case where a preset return condition is satisfied, it becomes possible to transition the state to the standby state that enables conducting the heel control.

[0145] In addition, in conducting the trim support control, the propulsion system 20 according to the present embodiment sets the trim support angles of the propulsion machines 3 on both sides in the left-right direction to the same value. Thus, the trim angle can be effectively adjusted in the boat 1 in the straight advancing state.

[0146] Further, in a case of conducting the heel control, the propulsion system 20 according to the present embodiment sets the heel suppression angle θd of the propulsion machine 3 on one side in the left-right direction to a value larger than the trim support angle, and also sets the heel suppression angle θd of the propulsion machine 3 on the other side in the left-right direction to a value smaller than the trim support angle. Thus, in a case where the heel angle θh of the boat 1 is large, the heel angle θh can be suppressed satisfactorily.

[0147] In addition, the propulsion system 20 according to the present embodiment includes the intermediate member 37 between the hull 2 and the propulsion machine 3 to increase the inclination angle of the propulsion machine 3 rearward in the propulsion direction. Thus, it becomes possible to further largely incline the propulsion machine 3 rearward in the propulsion direction of the boat 1, so that the trim angle can be made larger in the negative direction. Therefore, in a case where the heel angle θh of the boat 1 is large, the heel angle θh can be more effectively suppressed.

[0148] Note that the present invention is not limited to the above-described embodiments with reference to the drawings, and various modifications are conceivable within the technical scope.

[0149] For example, in the above embodiment, the trim support control, the heel control, and the like are conducted, based on the boat speed V. However, the trim support control, the heel control, and the like may be conducted, based on the rotation speed of the propulsion machine 3 instead of the boat speed V.

[0150] In addition, in the above embodiment, while the boat 1 is advancing straight, the case where only the trim support control is conducted and the case where the trim support control and the heel control are both conducted in accordance with the boat speed V have been given as examples. However, while the boat 1 is advancing straight, it is also possible to conduct only the heel control in accordance with the boat speed V, such as a case where the boat operator cancels the trim support control in setting.

[0151] Further, in the above-described embodiment, the trim support control, the heel control, and the like are conducted, based on the actual steering angle detected by the actual steering angle sensor 67. However, the trim support control, the heel control, and the like may be conducted, based on the steering instruction angle of the steering angle inputter 71.

[0152] In the above embodiment, one propulsion machine 3 is provided on each of both left and right sides, but a plurality of propulsion machines 3 may be provided on each of both left and right sides.

[0153] In addition, the procedure and contents of the control conducted by the controller 8 can be changed as appropriate.

[0154] Then, the constitution in the above embodiment is an example of the present invention, and various changes can be made without departing from the gist of the present invention.

[0155] While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.REFERENCE SIGNS LIST1 Boat

[0157] 2 Hull

[0158] 3 Propulsion Machine

[0159] 3a Right propulsion machine

[0160] 3b Left propulsion machine

[0161] 6 Detector

[0162] 7 Operation unit

[0163] 8 Controller

[0164] 20 Propulsion system

[0165] 32 Drive source

[0166] 34 Propulsor

[0167] 36 Steering shaft

[0168] 37 Intermediate member

[0169] 45 Trim angle adjuster

[0170] 63 Steering angle sensor (steering angle detector)

[0171] 71 Steering angle inputter

Examples

Embodiment Construction

[0037]Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that it is assumed that front, rear, upper, lower, left, and right directions in the following description respectively coincide with the directions of a boat 1. In this case, an arrow FR in the drawing indicates a forward side of the boat 1, an arrow UP in the drawing indicates an upper side of the boat 1, and an arrow LH in the drawing indicates a leftward side of the boat 1. In addition, a center line CL indicates the center position of the boat 1 in a left-right direction (a width direction).

[0038]FIG. 1 is a plan view of the boat according to an embodiment. FIG. 2 is a functional block diagram of a propulsion system of the boat.

[0039]As illustrated in FIG. 1, the boat 1 includes: a hull 2; and a propulsion system 20, which is provided on the hull 2.

[0040]As illustrated in FIGS. 1 and 2, the propulsion system 20 includes a plurality of propulsion machines 3, an operatio...

Claims

1. A propulsion system of a boat, the propulsion system comprising:at least one propulsion machine including a drive source, and a propulsor configured to generate thrust with dynamic power transmitted from the drive source, the at least one propulsion machine being provided on each of both sides in a left-right direction with respect to a center of a hull;a trim angle adjuster configured to adjust a trim angle of each of the propulsion machines on the both sides in the left-right direction with respect to the hull; anda controller configured to control the trim angle adjuster, whereinthe controller is capable of conducting trim support control and heel control, the trim support control causing the trim angle adjuster to adjust the trim angle to a trim support angle set in accordance with either a preset boat speed or a rotation speed of a propulsion machine, the heel control causing the trim angle adjuster to adjust the trim angle to a heel suppression angle set in accordance with an inclination in a roll direction of the hull to suppress the inclination in the roll direction of the hull, andin a case where a preset condition is satisfied, the controller conducts the heel control in addition to the trim support control, and causes the trim angle adjuster to adjust the trim angle to the heel suppression angle set with reference to the trim support angle of the propulsion machine.

2. The propulsion system of the boat according to claim 1, further comprising a heel angle detector configured to detect a heel angle corresponding to an inclination in a roll direction of the hull, whereinin a case where the heel angle is equal to or larger than a preset heel angle reference value, the controller conducts the heel control.

3. The propulsion system of the boat according to claim 1, further comprising a steering angle detector configured to detect a steering angle around a steering shaft of the propulsion machine with respect to the hull, whereinin a case where it is determined that the boat is advancing straight, based on a detection value of a steering angle detected by the steering angle detector, the controller enables conducting the heel control.

4. The propulsion system of the boat according to claim 3, whereinin a case where it is determined that the boat is turning, based on a detection value of the steering angle of the steering angle detector, the controller stops conducting the trim support control and the heel control.

5. The propulsion system of the boat according to claim 1, further comprising a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, whereinwhile conducting the heel control, upon receipt of an operation input from the trim angle operation unit, the controller stops conducting the heel control.

6. The propulsion system of the boat according to claim 2, further comprising a trim angle operation unit configured to operate the trim angle adjuster in accordance with an external input, whereinwhile conducting the heel control, upon receipt of an operation input from the trim angle operation unit, the controller stops conducting the heel control.

7. The propulsion system of the boat according to claim 5, whereinin a state in which the operation input from the trim angle operation unit is received and conducting the heel control is stopped, and in a case where a preset return condition is satisfied, the controller enables conducting the heel control.

8. The propulsion system of the boat according to claim 1, whereinin conducting the trim support control, the controller sets the trim support angles of the propulsion machines on the both sides in the left-right direction to an identical value.

9. The propulsion system of the boat according to claim 2, whereinin conducting the trim support control, the controller sets the trim support angles of the propulsion machines on the both sides in the left-right direction to an identical value.

10. The propulsion system of the boat according to claim 1, whereinin conducting the heel control, the controller sets the heel suppression angle of the propulsion machine on one side in the left-right direction to a value larger than the trim support angle, and also sets the heel suppression angle of the propulsion machine on the other side in the left-right direction to a value smaller than the trim support angle.

11. The propulsion system of the boat according to claim 2, whereinin conducting the heel control, the controller sets the heel suppression angle of the propulsion machine on one side in the left-right direction to a value larger than the trim support angle, and also sets the heel suppression angle of the propulsion machine on the other side in the left-right direction to a value smaller than the trim support angle.

12. The propulsion system of the boat according to claim 1, further comprising an intermediate member provided between the hull and the propulsion machine, the intermediate member increasing a rearward inclination angle in a propulsion direction of the propulsion machine.

13. The propulsion system of the boat according to claim 2, further comprising an intermediate member provided between the hull and the propulsion machine, the intermediate member increasing a rearward inclination angle in a propulsion direction of the propulsion machine.

Images