Patent ID: 12252227

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are hereinafter described with reference to the drawings.

The structures of a marine propulsion system100and a marine vessel110according to preferred embodiments of the present invention are now described with reference toFIGS.1to8. In the figures, arrow FWD represents the front of the marine vessel110, arrow BWD represents the rear of the marine vessel110, arrow L represents the left (port side) of the marine vessel110, and arrow R represents the right (starboard side) of the marine vessel110.

As shown inFIG.1, the marine vessel110includes a hull10and the marine propulsion system100. The marine propulsion system100is provided on or in the hull10. The marine propulsion system100propels the marine vessel110. The marine vessel110may be a relatively small marine vessel used for sightseeing or fishing, for example.

The marine propulsion system100includes a main propulsion device20, an auxiliary propulsion device30, an operator40, a controller50, a display60, and a battery70. The operator40, the controller50, the display60, and the battery70are provided on or in the hull10.

As shown inFIG.2, only one main propulsion device20is attached to a stern11of the hull10. The main propulsion device20is located on a centerline91of the hull10in a right-left direction.

As shown inFIG.3, the main propulsion device20includes a main propulsion device main body20aand a bracket20b. The main propulsion device main body20ais attached to the stern11of the hull10via the bracket20b.

The main propulsion device20is an engine outboard motor including an engine22to drive a main propeller21that generates a thrust. Specifically, the main propulsion device main body20aincludes the engine22, a drive shaft23, a gearing24, a propeller shaft25, and the main propeller21. The engine22is an internal combustion engine that generates a driving force. The driving force of the engine22is transmitted to the main propeller21via the drive shaft23, the gearing24, and the propeller shaft25. The main propeller21generates a thrust by rotating in the water by the driving force transmitted from the engine22. The main propeller21is an example of a “main thruster”.

The main propulsion device main body20aincludes a shift actuator26that switches the shift state of the main propulsion device20. The shift actuator26switches the shift state of the main propulsion device20between a forward movement state, a rearward movement state, and a neutral state by switching the meshing of the gearing24. In the forward movement state, a driving force is transmitted from the engine22to the main propeller21to generate a forward thrust from the main propeller21. In the rearward movement state, a driving force is transmitted from the engine22to the main propeller21to generate a rearward thrust from the main propeller21. In the neutral state, a driving force is not transmitted from the engine22to the main propeller21in order to not generate a thrust in the main propeller21. In the main propulsion device20, when the shift state of the main propulsion device20is switched, the gearing24generates relatively loud noises and vibrations.

The main propulsion device20rotates in the right-left direction to change the direction of a thrust.

Specifically, a steering27is provided on the bracket20b. The steering27includes a steering shaft27athat extends in an upward-downward direction. The main propulsion device main body20ais rotated in the right-left direction by the steering27about the steering shaft27awith respect to the bracket20b. When the main propulsion device main body20arotates in the right-left direction about the steering shaft27a, the orientation of the main propeller21also rotates in the right-left direction. Thus, the direction of the thrust of the main propeller21is changed. In the following description, changing the direction of the thrust of the main propeller21by rotating the orientation of the main propeller21in the right-left direction is referred to as “steering the main propulsion device20”.

As shown inFIG.2, the main propulsion device20is steerable by about 30 degrees to each of the L side and the R side. That is, a steering angle range A10, which is an angular range in which the main propulsion device20is steerable, is about 60 degrees.

As shown inFIG.1, the main propulsion device20includes an engine control unit (ECU)28and a steering control unit (SCU)29. The ECU28controls driving of the engine22and driving of the shift actuator26based on a control performed by the controller50. The SCU29controls driving of the steering27based on a control performed by the controller50. The ECU28and the SCU29include a control circuit including a central processing unit (CPU), for example.

As shown inFIG.2, only one auxiliary propulsion device30is attached to the stern11of the hull10. The auxiliary propulsion device30is provided to one side of the hull10in the right-left direction. In the marine propulsion system100, the auxiliary propulsion device30is provided to the L side of the hull10, and no auxiliary propulsion device is provided to the R side of the hull10.

As shown inFIG.4, the auxiliary propulsion device30includes a cowling30a, an upper case30b, a lower case30c, and a duct30d. The cowling30a, the upper case30b, the lower case30c, and the duct30dare aligned in this order from top to bottom. The cowling30ais attached to the stern11of the hull10.

The auxiliary propulsion device30is preferably an electric outboard motor including an electric motor32to drive an auxiliary propeller31that generates a thrust. Specifically, the auxiliary propulsion device30includes the electric motor32and the auxiliary propeller31. The electric motor32is provided in the duct30d. The auxiliary propeller31is provided in the duct30d. The electric motor32is driven by power supplied from the battery70provided in the hull10. The electric motor32includes a stator32athat is integral and unitary with the duct30d, and a rotor32bthat is integral and unitary with the auxiliary propeller31. The auxiliary propeller31generates a thrust by rotating in the water by a driving force transmitted from the electric motor32. The auxiliary propeller31is an example of an “auxiliary thruster”.

When the auxiliary propeller31is rotated forward, a forward thrust is generated from the auxiliary propeller31. When the auxiliary propeller31is rotated backward, a rearward thrust is generated from the auxiliary propeller31. When the auxiliary propeller31is stopped, a thrust is not generated from the auxiliary propeller31. That is, in the auxiliary propulsion device30, it is not necessary to switch the meshing of the gearing24(seeFIG.3) unlike the main propeller21(seeFIG.3) of the main propulsion device20(seeFIG.3). Thus, the auxiliary propulsion device30does not generate relatively loud noises or vibrations unlike the main propulsion device20.

The auxiliary propulsion device30rotates in the right-left direction to change the direction of a thrust. Specifically, a steering33is provided in the auxiliary propulsion device30. The steering33includes a steering shaft33afixed to the lower case30cand extending in the upward-downward direction. An upper end of the steering shaft33ais located in the upper case30b. A lower end of the steering shaft33ais fixed to the duct30d. The duct30dand the lower case30care rotatable in the right-left direction by the steering33about the steering shaft33awith respect to the cowling30aand the upper case30b. When the duct30drotates in the right-left direction about the steering shaft33a, the orientation of the auxiliary propeller31also rotates in the right-left direction. Thus, the direction of the thrust of the auxiliary propeller31is changed. In the following description, changing the direction of the thrust of the auxiliary propeller31by rotating the orientation of the auxiliary propeller31in the right-left direction is referred to as “steering the auxiliary propulsion device30”.

As shown inFIG.2, the auxiliary propulsion device30is steerable by about 70 degrees to each of the L side and the R side. That is, a steering angle range A20, which is an angular range in which the auxiliary propulsion device30is steerable, is about 140 degrees.

As shown inFIG.1, the auxiliary propulsion device30includes a motor control unit (MCU)34and a steering control unit (SCU)35. The MCU34and the SCU35include a control circuit including a CPU, for example. The MCU34controls driving of the electric motor32based on a control performed by the controller50. The SCU35controls driving of the steering33based on a control performed by the controller50.

As shown inFIG.5, the maximum output of the auxiliary propulsion device30is smaller than that of the main propulsion device20. Specifically, the maximum value T11and the minimum value T12of the power range T10of the engine22of the main propulsion device20are larger than the maximum value T21and the minimum value T22of the power range T20of the electric motor32of the auxiliary propulsion device30, respectively. The minimum value T12of the power range T10of the engine22is smaller than the maximum value T21of the power range T20of the electric motor32. That is, the power range T10of the engine22of the main propulsion device20and the power range T20of the electric motor32of the auxiliary propulsion device30overlap each other between the maximum value T21of the power range T20of the electric motor32and the minimum value T12of the power range T10of the engine22.

As shown inFIG.1, the operator40receives a user's operation in order to operate (maneuver) the hull10. The operator40includes a remote control41, a steering wheel42, and a joystick43. The joystick43is an example of an “operator”.

The remote control41includes a lever. The steering wheel42is rotatable. The hull10is operated by combining an operation on the lever of the remote control41and an operation to rotate the steering wheel42.

As shown inFIG.6, the joystick43includes a base43aand a lever43b. The lever43bis tiltably and rotatably attached to the base43a. The lever43bis urged by an urging member such as a spring to automatically return to a neutral position P10when not operated by the user. At the neutral position P10, the lever43bis upright and is not rotated.

Operations on the joystick43are roughly divided into three operations: an operation to tilt the lever43b, an operation to tilt and rotate the lever43b, and an operation to rotate the lever43b. The operation to tilt the lever43bcorresponds to an operation to translate the hull10(seeFIG.1). The translation includes forward and rearward movements, lateral movements, and diagonal movements. The operation to tilt and rotate the lever43bcorresponds to an operation to turn the hull10. The turning includes clockwise turning and counterclockwise turning. The operation to rotate the lever43bcorresponds to an operation to rotate the hull10. In the following description, for convenience of explanation, “tilting the lever43b” and “rotating the lever43b” are referred to as “tilting the joystick43” and “rotating the joystick43”, respectively.

A joystick mode switch43cis provided on the base43aof the joystick43. In the marine propulsion system100, the joystick mode switch43cis pressed to switch between a state in which the controller50controls driving of the main propulsion device20and driving of the auxiliary propulsion device30based on an operation on the joystick43(joystick mode) and a state in which the controller50controls driving of the main propulsion device20and driving of the auxiliary propulsion device30based on operations on the remote control41and the steering wheel42(non-joystick mode). When the marine propulsion system100is in the joystick mode, operations on the remote control41and the steering wheel42are not received. When the marine propulsion system100is in the non-joystick mode, an operation on the joystick43is not received.

As shown inFIG.1, the controller50controls the ECU28of the main propulsion device20, the SCU29of the main propulsion device20, the MCU34of the auxiliary propulsion device30, and the SCU29of the auxiliary propulsion device30based on an operation on the operator40. That is, the controller50controls driving of the main propulsion device20and driving of the auxiliary propulsion device30based on a predetermined operation on the operator40. The controller50includes a control circuit including a CPU, for example. The marine propulsion system100includes an engine drive mode in which the hull10is moved in the forward-rearward direction by driving the main propulsion device20corresponding to an engine outboard motor, and an electric drive mode in which the hull10is moved in the forward-rearward direction by driving the auxiliary propulsion device30corresponding to an electric outboard motor.

As shown inFIG.7, when the joystick43is operated to move the hull10along the forward-rearward direction (the joystick43is tilted in the forward-rearward direction) in the engine drive mode, the controller50controls driving of the main propulsion device20to move the hull10along the forward-rearward direction. On the other hand, when the joystick43is operated to move the hull10along the forward-rearward direction in the electric drive mode, the controller50controls driving of the auxiliary propulsion device30to move the hull10along the forward-rearward direction. That is, when the joystick43is operated to move the hull10along the forward-rearward direction in the electric drive mode, motorized forward-rearward movement is performed to move the hull10along the forward-rearward direction by driving the auxiliary propulsion device30without generating a thrust from the main propulsion device20. The motorized forward-rearward movement is described below in detail.

When the joystick43is operated to move the hull10laterally and diagonally (the joystick43is tilted laterally and diagonally) in each of the engine drive mode and the electric drive mode, the controller50controls driving of the main propulsion device20and driving of the auxiliary propulsion device30to move the hull10laterally and diagonally. That is, the controller50performs a control to move the hull10laterally and diagonally by driving both the main propulsion device20and the auxiliary propulsion device30when the joystick43is tilted laterally and diagonally in the electric drive mode in which the motorized forward-rearward movement is possible, respectively.

When the engine22is stopped, the controller50does not perform a control to move the hull10laterally and diagonally even when the joystick43is tilted laterally and diagonally in the electric drive mode. Specifically, when the joystick43is tilted laterally and diagonally in the electric drive mode, the controller50determines whether or not the engine22is stopped. When the engine22is stopped, the controller50does not perform a control to move the hull10laterally and diagonally. On the other hand, when the engine22is operating, the controller50performs a control to move the hull10laterally and diagonally. The controller50performs a control to notify a vessel operator that the engine22is stopped when the engine22is stopped in the electric drive mode. The notification that the engine22is stopped may be displayed on the display60, or may be made by generating a sound, for example.

When the joystick43is operated to rotate the hull10(the joystick43is rotated) in each of the engine drive mode and the electric drive mode, the controller50controls driving of the auxiliary propulsion device30to rotate the hull10. That is, the controller50performs a control to rotate the hull10by driving the auxiliary propulsion device30without generating a thrust from the main propulsion device20when the joystick43is rotated in the electric drive mode in which the motorized forward-rearward movement is possible.

The controller50performs a control to switch between the engine drive mode and the electric drive mode when an operation is performed to switch between the engine drive mode and the electric drive mode. For example, the display60(seeFIG.1) may be a touch panel, and a button (hereinafter referred to as a mode switching button) displayed on the display60may be touched to switch between the engine drive mode and the electric drive mode. Alternatively, a mode switching button may be provided on the joystick43and be operated to switch between the engine drive mode and the electric drive mode. Alternatively, a mode switching button may be provided in the vicinity of or adjacent to a vessel operator's seat of the hull10and be operated to switch between the engine drive mode and the electric drive mode.

The controller50performs a control to shift to the electric drive mode when the joystick43is in a neutral state in the joystick mode or when the non-joystick mode is on. Specifically, when an operation is performed to switch between the engine drive mode and the electric drive mode in the engine drive mode, the controller50determines whether or not the marine propulsion system100(seeFIG.1) is in the joystick mode and the joystick43is in the neutral state. When the marine propulsion system100is in the joystick mode and the joystick43is in the neutral state, the controller50performs a control to shift from the engine drive mode to the electric drive mode. On the other hand, when the marine propulsion system100is not in the joystick mode or the joystick43is not in the neutral state, the controller50does not perform a control to shift from the engine drive mode to the electric drive mode. The marine propulsion system100performs a similar control when the electric drive mode is switched to the engine drive mode.

The controller50does not perform a control to shift to the electric drive mode in which the motorized forward-rearward movement is possible when the remaining amount of the battery70(seeFIG.1) is smaller than a predetermined threshold. Specifically, when an operation is performed to switch between the engine drive mode and the electric drive mode in the engine drive mode, the controller50determines whether or not the remaining amount of the battery70is smaller than the predetermined threshold. When the remaining amount of the battery70is smaller than the predetermined threshold, the controller50does not perform a control to shift from the engine drive mode to the electric drive mode. On the other hand, when the remaining amount of the battery70is equal to or larger than the predetermined threshold, the controller50performs a control to shift from the engine drive mode to the electric drive mode.

As shown inFIG.8, the controller50(seeFIG.1) performs a rudder angle change control to change the rudder angle A2of the auxiliary propulsion device30by a predetermined angle α to one side (L side) in the right-left direction of the hull10with respect to the forward-rearward direction of the hull10so as to move the hull10in the forward-rearward direction when the motorized forward-rearward movement is performed. Specifically, as shown inFIG.9, the auxiliary propulsion device30is provided to one side (L side) in the right-left direction of the hull10, and thus the hull10is turned when a thrust is generated in the forward-rearward direction from the auxiliary propulsion device30. Therefore, as shown inFIG.8, the rudder angle change control is performed to change the rudder angle A2of the auxiliary propulsion device30by the predetermined angle α to one side (L side) in the right-left direction of the hull10with respect to the forward-rearward direction of the hull10such that the rudder angle A2of the auxiliary propulsion device30is changed to generate a thrust from the auxiliary propulsion device30so as to move the hull10along the forward-rearward direction without rotating the hull10. The controller50performs the rudder angle change control when the joystick43is tilted in the forward-rearward direction in the electric drive mode in which the motorized forward-rearward movement is possible.

The predetermined angle α that causes the auxiliary propulsion device30to generate a thrust to move the hull10along the forward-rearward direction varies depending on the shape and size of the hull10, the attachment position of the auxiliary propulsion device30to the hull10, etc. Therefore, the controller50(seeFIG.1) performs a calibration control to adjust the predetermined angle α according to the hull10.

Specifically, in the marine vessel110in which the calibration control is not performed, the vessel operator tilts the joystick43(seeFIG.1) to move the hull10in the forward-rearward direction. At this time, the tilting direction of the joystick43is deviated from the forward-rearward direction. That is, in the marine vessel110in which the calibration control is not performed, the tilting direction of the joystick43and the moving direction of the hull10do not match. Then, while tilting the joystick43to move the hull10in the forward-rearward direction, the vessel operator performs an operation (pressing a calibration button, for example) to memorize the tilting direction of the joystick43in which the hull10moves in the forward-rearward direction. After that, when the joystick43is tilted in the forward-rearward direction, the controller50(seeFIG.1) controls the rudder angle A2of the auxiliary propulsion device30to move the hull10in the forward-rearward direction. The calibration control may be performed at the time of the initial operation of the marine propulsion system100, or after the attachment position of the auxiliary propulsion device30to the hull10is changed, for example.

When the motorized forward-rearward movement is performed, the rudder angle A1of the main propulsion device20is maintained at zero. That is, the controller50performs a control to perform the motorized forward-rearward movement while the rudder angle A1of the main propulsion device20is maintained in the forward-rearward direction of the hull10.

According to the various preferred embodiments of the present invention described above, the following advantageous effects are achieved.

According to a preferred embodiment of the present invention, the controller50is configured or programmed to perform the rudder angle change control to change the rudder angle A2of the auxiliary propulsion device30by the predetermined angle α to one side in the right-left direction of the hull10with respect to the forward-rearward direction of the hull10so as to move the hull10along the forward-rearward direction when the motorized forward-rearward movement is performed to move the hull10along the forward-rearward direction by driving the auxiliary propulsion device30that is provided to one side of the hull10in the right-left direction without generating a thrust from the main propulsion device20. Accordingly, the rudder angle change control is performed when the motorized forward-rearward movement is performed by the auxiliary propulsion device30that is provided to one side of the hull10in the right-left direction without generating a thrust from the main propulsion device20such that check helm is automatically performed to prevent rotation of the hull10due to the auxiliary propulsion device30being provided to one side of the hull10in the right-left direction. Consequently, the motorized forward-rearward movement is performed as intended by the vessel operator by the auxiliary propulsion device30that is provided to one side of the hull10in the right-left direction without generating a thrust from the main propulsion device20.

According to a preferred embodiment of the present invention, the marine propulsion system100performs the motorized forward-rearward movement to move the hull10along the forward-rearward direction by driving the auxiliary propulsion device30including the electric motor32without generating a thrust from the main propulsion device20including the engine22. Accordingly, unlike the engine22, the electric motor32does not directly emit carbon dioxide, and thus a preferable device structure is achieved from the viewpoint of SDGs.

According to a preferred embodiment of the present invention, the controller50is configured or programmed to perform the calibration control to adjust the predetermined angle α according to the hull10. Accordingly, the calibration control is performed such that the predetermined angle α by which the rudder angle A2of the auxiliary propulsion device30is turned to move the hull10along the forward-rearward direction when the motorized forward-rearward movement is performed is adjusted according to the shape and size of the hull10, the attachment positions of the main propulsion device20and the auxiliary propulsion device30to the hull10, etc.

According to a preferred embodiment of the present invention, the controller50is configured or programmed to perform a control to perform the motorized forward-rearward movement while the rudder angle A1of the main propulsion device20is maintained in the forward-rearward direction of the hull10. Accordingly, it is not necessary to change the rudder angle A1of the main propulsion device20each time the motorized forward-rearward movement is performed, and thus the hull10is prevented from swinging due to a change in the rudder angle A1of the main propulsion device20.

According to a preferred embodiment of the present invention, the operator40includes the joystick43. The controller50is configured or programmed to perform the rudder angle change control when the joystick43is tilted in the forward-rearward direction in the electric drive mode in which the motorized forward-rearward movement is possible. Accordingly, the operating direction (forward-rearward direction) of the joystick43is the same as the moving direction (forward-rearward direction) of the hull10, and thus in the electric drive mode, the joystick43is operated in an intuitively easy-to-understand state to move the hull10along the forward-rearward direction.

According to a preferred embodiment of the present invention, the controller50is configured or programmed to perform a control to shift to the electric drive mode when the joystick43is in the neutral state in the joystick mode in which driving of the main propulsion device20and the auxiliary propulsion device30is controlled based on an operation on the joystick43, or when the non-joystick mode is on in which driving of the main propulsion device20and the auxiliary propulsion device30is controlled based on an operation on the operator40other than the joystick43. Accordingly, the marine propulsion system100shifts to the electric drive mode only when the joystick43is not operated, and thus erroneous transition to the electric drive mode during control of driving of the main propulsion device20and the auxiliary propulsion device30based on an operation on the joystick43is prevented.

According to a preferred embodiment of the present invention, the controller50is configured or programmed to not perform a control to shift to the electric drive mode in which the motorized forward-rearward movement is possible when the remaining amount of the battery70that supplies power to the electric motor32of the auxiliary propulsion device30is smaller than the predetermined threshold. Accordingly, transition to the electric drive mode in a state in which the motorized forward-rearward movement is performed only for a relatively short time due to low battery or in a state in which the motorized forward-rearward movement is not possible is prevented.

According to a preferred embodiment of the present invention, the operator40includes the joystick43. The controller50is configured or programmed to perform a control to move the hull10laterally and diagonally by driving both the main propulsion device20and the auxiliary propulsion device30when the joystick43is tilted laterally and diagonally in the electric drive mode in which the motorized forward-rearward movement is possible, respectively. Accordingly, the operating direction (lateral direction and diagonal direction) of the joystick43is the same as the moving direction (lateral direction and diagonal direction) of the hull10, and thus in the electric drive mode, the joystick43is operated in an intuitively easy-to-understand state to move the hull10laterally and diagonally.

According to a preferred embodiment of the present invention, the controller50is configured or programmed to not perform a control to move the hull10laterally and diagonally even when the joystick43is tilted laterally and diagonally when the engine22is stopped in the electric drive mode. Accordingly, in the electric drive mode, the engine22is stopped when a control to move the hull10laterally and diagonally is not performed as in a case of the motorized forward-rearward movement.

According to a preferred embodiment of the present invention, the controller50is configured or programmed to perform a control to notify the vessel operator that the engine22is stopped when the engine22is stopped in the electric drive mode. Accordingly, when the engine22is stopped in the electric drive mode, the vessel operator easily recognizes from the notification that the hull10is not able to be moved laterally and diagonally due to the engine22being stopped even when the joystick43is tilted laterally and diagonally.

According to a preferred embodiment of the present invention, the operator40includes the joystick43. The controller50is configured or programmed to perform a control to rotate the hull10by driving the auxiliary propulsion device30without generating a thrust from the main propulsion device20when the joystick43is rotated in the electric drive mode in which the motorized forward-rearward movement is possible. Accordingly, the operating direction (rotating direction) of the joystick43is the same as the moving direction (rotating direction) of the hull10, and thus in the electric drive mode, the joystick43is operated in an intuitively easy-to-understand state to rotate the hull10.

According to a preferred embodiment of the present invention, the main propulsion device20is an engine outboard motor including the engine22to drive the main propeller21corresponding to a main thruster and provided on the centerline91of the hull10in the right-left direction. The auxiliary propulsion device30is an electric outboard motor including the electric motor32to drive the auxiliary propeller31corresponding to an auxiliary thruster and provided to one side of the centerline91of the hull10in the right-left direction. Accordingly, in a structure in which the main propulsion device20and the auxiliary propulsion device30are an engine outboard motor and an electric outboard motor, respectively, the motorized forward-rearward movement is performed as intended by the vessel operator by the auxiliary propulsion device30that is provided to one side of the hull10in the right-left direction without generating a thrust from the main propulsion device20.

The preferred embodiments of the present invention described above are illustrative in all points and not restrictive. The extent of the present invention is not defined by the above description of the preferred embodiments but by the scope of the claims, and all modifications within the meaning and range equivalent to the scope of the claims are further included.

For example, while the main propulsion device20is preferably an engine outboard motor, and the auxiliary propulsion device30is preferably an electric outboard motor in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the main propulsion device and the auxiliary propulsion device may alternatively be inboard motors enclosed within the hull instead of outboard motors, or inboard-outboard motors partially enclosed within the hull.

While the controller50preferably performs a control to rotate the hull10by driving the auxiliary propulsion device30without generating a thrust from the main propulsion device20when the joystick43is rotated in the electric drive mode in which the motorized forward-rearward movement is possible in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the controller may alternatively perform a control to rotate the hull by driving the auxiliary propulsion device without generating a thrust from the main propulsion device when an operator other than the joystick is operated to rotate the hull in the electric drive mode in which the motorized forward-rearward movement.

While the controller50preferably performs a control to notify the vessel operator that the engine22is stopped when the engine22is stopped in the electric drive mode in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the controller may not perform a control to notify the vessel operator that the engine is stopped when the engine is stopped in the electric drive mode.

While the controller50preferably does not perform a control to move the hull10laterally and diagonally even when the joystick43is tilted laterally and diagonally when the engine22is stopped in the electric drive mode in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the controller may alternatively perform a control to move the hull laterally and diagonally when the joystick is tilted laterally and diagonally even when the engine is stopped in the electric drive mode.

While the controller50preferably performs a control to move the hull10laterally and diagonally by driving both the main propulsion device20and the auxiliary propulsion device30when the joystick43is tilted laterally and diagonally in the electric drive mode in which the motorized forward-rearward movement is possible, respectively, in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the controller may alternatively perform a control to move the hull laterally and diagonally by driving both the main propulsion device and the auxiliary propulsion device when an operator other than the joystick is operated to move the hull laterally and diagonally in the electric drive mode in which the motorized forward-rearward movement is possible, respectively.

While the controller50preferably performs a control to shift to the electric drive mode when the joystick43is in the neutral state in the joystick mode in which driving of the main propulsion device20and the auxiliary propulsion device30is controlled based on an operation on the joystick43, or when the non-joystick mode is on in which driving of the main propulsion device20and the auxiliary propulsion device30is controlled based on an operation on the operator40other than the joystick43in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the controller may alternatively perform a control to shift to the electric drive mode when the joystick is not in the neutral state in the joystick mode or when the joystick mode is not on.

While the controller50preferably performs the rudder angle change control when the joystick43is tilted in the forward-rearward direction in the electric drive mode in which the motorized forward-rearward movement is possible in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the controller may alternatively perform the rudder angle change control when an operator other than the joystick is operated to move the hull along the forward-rearward direction in the electric drive mode in which the motorized forward-rearward movement is possible.

While the controller50preferably performs a control to perform the motorized forward-rearward movement while the rudder angle A1of the main propulsion device20is maintained in the forward-rearward direction of the hull10in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the controller may alternatively perform a control to perform the motorized forward-rearward movement while the rudder angle of the main propulsion device is turned with respect to the forward-rearward direction of the hull.

While the controller50preferably performs the calibration control to adjust the predetermined angle α according to the hull10in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the controller may not perform the calibration control to adjust the predetermined angle according to the hull. In such a case, the rudder angle of the auxiliary propulsion device may be manually set by the vessel operator when the auxiliary propulsion device is driven to move the hull along the forward-rearward direction, for example.

While only one main propulsion device20is preferably attached to the stern11of the hull10in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, two or more main propulsion devices may alternatively be attached to the stern of the hull.

While only one auxiliary propulsion device30is preferably attached to the stern11of the hull10in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, two or more auxiliary propulsion devices may alternatively be attached to the stern of the hull.

While the main propulsion device20is preferably steerable by about 30 degrees to each of the L side (the left side of the hull) and the R side (the right side of the hull) in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the main propulsion device may alternatively be steerable by an angle other than about 30 degrees to each of the left side and the right side of the hull.

While the auxiliary propulsion device30is preferably steerable by about 70 degrees to each of the L side (the left side of the hull) and the R side (the right side of the hull) in preferred embodiments described above, the present invention is not restricted to this. In a preferred embodiment of the present invention, the auxiliary propulsion device may alternatively be steerable by an angle other than about 70 degrees to each of the left side and the right side of the hull.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.