Marine Vessel and Control Device Therefor

This application claims the benefit of priority to Japanese Patent Application No. 2024-100106, filed on Jun. 21, 2024, the entire contents of which are incorporated herein by reference.

Example embodiments disclosed herein relate to marine vessels and control devices therefor.

Among fishing methods primarily involving small marine vessels, there is a technique commonly known as drift fishing in which the hull of a vessel is allowed to drift freely with the tidal current without anchoring while fishing. In drift fishing, depending on the difference between the tidal current direction and the wind direction, as well as the wind speed, the effects on the hull and the fishing line may differ sometimes causing the two to move differently. As a result, issues such as fishing line entanglement may occur, which may impede the drift fishing.

If a buoy with a shape designed to be less susceptible to wind floats on water, and the vessel is maneuvered to follow the buoy, the vessel is expected to move along with the tidal current, making drift fishing easier. Japanese Laid-Open Patent Publication No. H09-295600 discloses a technology for automatically maneuvering a marine vessel so as to maintain a constant relative distance between the vessel and an ocean buoy. However, when the conventional technology is applied to control a vessel to follow a buoy, frequent use of a propulsion device is required, resulting in reduced quietness, which makes this technology not necessarily suitable for drift fishing.

Meanwhile, Japanese Patent No. 2851130, Japanese Laid-Open Patent Publication No. H11-43097, and Japanese Laid-Open Patent Publication No. 2000-142584 disclose technologies in which a resistance member, such as a sea anchor, which receives water resistance is submerged in water enabling the hull to be more strongly affected by the tidal current than by the wind. However, in these conventional technologies, since the resistance member is operated manually, it is not easy to maneuver the hull to move with the fishing line.

Thus, there is still room for improvement in achieving easy drift fishing.

Example embodiments of the present invention provide control devices for marine vessels that facilitate easy drift fishing.

In an example embodiment of the present invention, a control device for a marine vessel includes a hull, a pair of water resistance bodies, and a controller. The pair of water resistance bodies are provided on the hull, one on a left side and one on a right of the hull, each independently movable between a first position in which a resistance received from water in a predetermined direction is adjustable to a first magnitude, and a second position in which a resistance is adjustable to zero or to a second magnitude smaller than the first magnitude. The controller is configured or programmed to acquire a relative distance between a buoy, which floats on the water in a free-drifting manner, and the hull. The controller is configured or programmed to control the pair of water resistance bodies based on the relative distance.

In the above configuration, the pair of water resistance bodies can be moved independently and are provided in at least one pair on the hull, with one on the left side and one on the right side. The pair of water resistance bodies are movable between the first position in which the resistance received from water in a predetermined direction is adjustable to the first magnitude, and the second position in which the resistance is adjustable to zero or to the second magnitude smaller than the first magnitude. The relative distance between the buoy, which floats on the water in a free-drifting manner, and the hull is acquired, and the water resistance bodies are controlled based on the relative distance.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.

Example embodiments of the present invention will be described in detail with reference to the accompanying drawings.

are schematic top views of a marine vesselthat uses a control device according to an example embodiment of the present invention. The marine vesselincludes a hull.illustrate the states in which water resistance bodies(e.g., resistance plates described in more detail below) mounted to the hullare located in a second position and a first position, respectively.

A centerline C of the hullextends through the center of the stern and the tip of the bow. The centerline C also extends through the center of gravity G (turning center) of the marine vessel. The front-rear direction is parallel to the centerline C (hereinafter “parallel” includes both parallel and substantially parallel). The forward direction is a direction along the centerline C infrom the stern toward the bow. The backward direction is a direction along the centerline C infrom the bow toward the stern. As used herein, the terms “left” and “right” are defined based on the perspective when the hullis viewed from the rear. The up-down direction is a direction perpendicular to both the front-rear direction and the left-right direction (hereinafter “perpendicular” includes both perpendicular and substantially perpendicular).

The marine vesselincludes a steerable outboard motorand a steerable trolling motoras propulsion devices to propel the hull. The outboard motoris located at the stern, while the trolling motoris located at the bow. The outboard motorand the trolling motormay serve as the primary and auxiliary propulsion devices of the marine vessel, respectively.

The marine vesselfurther includes a steering wheelmainly used to steer, a remote control unitmainly used to adjust the output of the outboard motor, and a joystickmainly used to both steer and adjust the output of the outboard motor(see). The remote control unitincludes two throttle levers (not illustrated) that are operated to adjust the engine output of the outboard motorand to switch between forward and reverse travel. Each throttle lever is operable from a neutral position in both the forward and reverse directions.

As illustrated in, the outboard motorincludes an outboard motor bodyand a propeller. The outboard motor bodyis attached to the stern via an attachment mechanism, specifically to a swivel bracket (not illustrated) of the attachment mechanism so as to be pivotable about a steering axis center K. The steering angle of the outboard motorchanges as the outboard motor bodypivots about the steering axis center K. The trolling motoris configured to provide a propulsive force to the hullin any direction around a rotation axis J. For example, the trolling motormay be electrically powered.

A pair of left and right water resistance assembliesL andR are arranged at the stern. The water resistance assembliesL andR each include a rotary motor, a lifting motor, a water resistance body(e.g., a resistance plate), a fixed body, and a movable body. The water resistance assembliesL andR are arranged and configured symmetrically with respect to the centerline C. The water resistance assembliesL andR can be driven independently. Since their basic configurations are the same, the configuration of the water resistance assemblyL will be described as a representative example.

The fixed bodyis fixed to the stern, and the movable bodyis movable in the up-down direction relative to the fixed body(at least between a raised position and a lowered position). The water resistance bodyis pivotable about the rotation axis Jand is movable to the second position illustrated inand to the first position illustrated in. The rotation axis Jis the axis center of a pivot shaft that is parallel to the up-down direction.

are schematic right-side views of the marine vessel.

illustrate a state where the water resistance bodyis in the second position, whileillustrate a state where the water resistance bodyis in the first position.illustrate a state where the movable bodyis in the raised position, whileillustrate a state where the movable bodyis in the lowered position in a drift fishing mode other than during normal sailing.

The lifting motordrives the movable bodyto move it up and down relative to the fixed body. The rotary motorcauses the water resistance bodyto pivot about the rotational axis J. The lifting motorand the rotary motorare automatically controlled by a controller(described below) and can also be manually operated using a water resistance switch (SW)(see).

The first position is a position where the water resistance bodyis perpendicular to the front-rear direction. In this position, the water resistance bodydefines an angle of 90° (hereinafter, “90°” includes both 90° and substantially) 90° with respect to the centerline C as viewed from above. The second position is a position where the water resistance bodyis parallel to the front-rear direction. In this position, the water resistance bodydefines an angle of 0° (hereinafter, “0°” includes both 0° and substantially) 0° with respect to the centerline C as viewed from above.

When at least a portion of the water resistance bodyis submerged (e.g., when in the lowered position), the resistance received from the water in a predetermined direction (the front-rear direction in this example embodiment) is at a first magnitude in the first position (90°) and at a second magnitude, smaller than the first magnitude, in the second position (0°). In contrast, when the entire water resistance bodyis above the water surface, the resistance it receives from water is zero.

is a block diagram of a marine propulsion system including the control device for a marine vessel according to an example embodiment.

The marine propulsion system includes the controller, the outboard motor, the trolling motor, the steering wheel, the remote control unit, the joystick, a display, various sensors, various manual operators, and a memory. The marine propulsion system further includes the water resistance switch, a first global navigation satellite system (GNSS) sensor, a second GNSS sensor, a wind speed sensor, a tidal current sensor, the water resistance assembliesL andR, a receiver, and a buoy.

The water resistance switchincludes a left switchL and a right switchR, which are used to manually operate the water resistance bodiesof the water resistance assembliesL andR, respectively.

The controllermay include a CPU, a ROM, a RAM, and a timer (not illustrated), or processor circuitry configured to perform similar functions. The ROMstores a control program. The CPUloads the control program stored in the ROMinto the RAMand executes it, thus implementing various control operations. The RAMprovides a workspace for the CPUto execute the control program.

The outboard motorincludes an engine control unit (ECU), a steering control unit (SCU), a rotational speed sensor, an engine, a steering mechanism, various sensors, a steering angle sensor, and various actuators. The ECUand the SCUeach include a CPU (not illustrated). The ECUis configured or programmed to control the driving of the engineaccording to commands from the controller. The SCUis configured or programmed to control the driving of the steering mechanismaccording to commands from the controller.

The steering mechanismcauses the outboard motor bodyto pivot about the steering axis center K (see), thus changing the orientation of the outboard motor bodyin the left-right direction. This changes the direction of the propulsive force acting on the stern, where the outboard motor bodyis mounted. The steering mechanismmay be either electric or hydraulic. The various actuatorsmay include a power trim and tilt (PTT) mechanism that causes the outboard motorto pivot about the tilt axis.

The rotational speed sensordetects the rotation rate (revolutions per unit time) of the engine. The various sensorsinclude a throttle opening sensor and the like. The steering angle sensordetects the actual steering angle of the outboard motor. Note that the controllermay also obtain the actual steering angle from the steering command value output to the steering mechanism.

The trolling motorincludes an electric motor, a propeller (not illustrated) that generates a propulsive force when driven to rotate by the electric motor, and an electric steering unitthat rotates the electric motorabout the rotation axis J.

The steering unitincludes, for example, a servo motor. The orientation of the trolling motorcan be changed by the steering operation of the steering unit. Specifically, the steering unitrotates the electric motorabout the rotation axis Jto change its orientation within a range of 360 degrees or more, thus altering the direction of the propulsive force. This changes the steering angle of the trolling motor, which in turn changes the direction of the propulsive force that the trolling motorexerts on the hull.

The trolling motorincludes, in addition to the electric motorand the steering unit, a motor control unit (MCU), an SCU, a steering angle sensor, various sensors, and an actuator.

The MCUand the SCUeach include a CPU (not illustrated). The MCUis configured or programmed to control the driving of the electric motoraccording to commands from the controller. The maximum output of the electric motormay be less than that of the engineof the outboard motor. The SCUis configured or programmed to control the driving of the steering unitaccording to commands from the controller, thus changing the direction of the propulsive force acting on the bow, where the trolling motoris mounted.

The actuatormoves the trolling motorbetween a use position and a storage position. Note that it is not essential to provide a function to enable the trolling motorto transition between the use position and the storage position by power.

The steering angle sensordetects the steering angle of the trolling motor, which changes in response to the steering operation of the steering unit. Detection signals from the steering angle sensorand the various sensorsare supplied to the controller. It is not essential that the hull, the outboard motor, and the trolling motorbe equipped with all the sensors and actuators mentioned above.

Strictly speaking, the points where the propulsive forces of the propulsion devices act are their respective mounting locations on the hull. However, for convenience of explanation, it is assumed herein that the propulsive force of the trolling motoracts on the bow, and the propulsive force of the outboard motoracts at the location of the attachment mechanism at the stern.

The various sensorsinclude a hull speed sensor, a hull acceleration sensor, an orientation sensor, a distance sensor, an attitude sensor, and a position sensor (not illustrated). The various sensorsfurther include a sensor that detects the operation of the remote control unit, a sensor that detects the rotational angle position of the steering wheel, a sensor that detects the operation of each switch and paddle on the steering wheel, and a sensor that detects the operation of the joystick. The hull speed sensor detects the navigation speed (vessel speed) of the marine vessel(hull). Detection signals from the various sensorsare supplied to the controller.

The various operatorsinclude not only operators to maneuver the marine vessel but also setting operators to make various settings and input operators to enter various instructions (not illustrated). Some of the various operatorsmay be located on the steering wheel. The various operatorsare operated by the vessel operator, and the operation signals are supplied to the controller. The memoryis a read-write non-volatile storage medium.

The controllermay establish predetermined communication with the various sensorsand the various operatorsto exchange information with them. The displaydisplays various types of information.

The first GNSS sensorand the second GNSS sensorperiodically receive GNSS signals from GNSS satellites. As a result, the controllercan acquire the current position of each of the GNSS sensorsand. The first GNSS sensorand the second GNSS sensorare located at different positions. For example, the first GNSS sensorand the second GNSS sensorare arranged at different positions along the front-rear direction. Accordingly, it is possible to determine the hull orientation based on the signals received by the GNSS sensorsand, without the need for an orientation sensor.

The wind speed sensordetects the wind speed. The tidal current sensordetects the relative tidal current speed and relative tidal current direction as observed from the hull. The configuration of the tidal current sensoris not particularly limited. For example, the tidal current sensormay emit ultrasonic waves at an angle into the sea and analyze the reflected ultrasonic waves to determine the relative tidal current speed and relative tidal current direction.

The controllerdetermines the absolute tidal current speed based on the relative tidal current speed and the vessel speed. The controlleralso determines the absolute tidal current direction based on the relative tidal current direction and the direction of the vessel's movement. Hereinafter, unless otherwise specified, the terms “tidal current speed” and “tidal current direction” will refer to the absolute tidal current speed and the absolute tidal current direction, respectively.

The buoyfloats on the water and is allowed to drift freely in the drift fishing mode (described below). To minimize the wind effect (resistance), for example, the buoyis designed to protrude less above the water and have a flat top shape. It is desirable for the buoyto move in the same manner as the fishing line, even when exposed to the wind.

The buoyincludes a third GNSS sensorand a transmitter. The third GNSS sensorperiodically receives GNSS signals from GNSS satellites. This allows the buoyto acquire its current position. The transmitteris configured to output information indicating the position to the outside.

The receiverreceives the information output from the transmitter. This allows the controllerto acquire the current position of the buoy. There is no particular limitation on the communication method between the transmitterand the receiver. For example, medium-range or short-range wireless communication may be used.

The controlleris configured or programmed to acquire the relative distance D between the hulland the buoy. For example, the controlleracquires the relative distance D based on the current position of the hull, which is acquired by the first GNSS sensoror the second GNSS sensor, and the current position of the buoy, which is acquired by the receiver. The relative distance D may be acquired using a distance sensor provided on the hull, and the acquisition method may use radio waves, ultrasound, or light. In this context, it is not essential for the buoyto include the third GNSS sensorand the transmitter, nor is it essential for the hullto include the receiver.

The controlleralso acquires the relative orientation Bθ of the buoywith respect to the hull. The relative orientation Bθ is defined as the angle defined between an imaginary line extending through the center of gravity G of the hulland the buoy, as viewed from above, and the centerline C of the hull, in the forward direction (see). For example, the controllerfirst acquires the hull orientation from the orientation sensor or the GNSS sensorsand. The controllerthen acquires the relative orientation Bθ based on the current position of the hull, the current position of the buoy, and the hull orientation.

In this example embodiment, there are a plurality of vessel maneuvering modes, which can be broadly classified into an outboard motor mode that does not utilize the trolling motorand a cooperative mode that utilizes both the trolling motorand the outboard motor. The outboard motor mode is a maneuvering mode in which the outboard motoris controlled primarily based on the rotational operation of the steering wheeland the operation of the remote control unit. Other maneuvering modes include a drift fishing mode, which utilizes the water resistance assembliesL andR to achieve operations suitable for drift fishing. In the drift fishing mode, the trolling motorand/or the outboard motormay also be used.

is a flowchart of a drift fishing mode process.are schematic diagrams illustrating an example of a control in the drift fishing mode process.