watercraft

Abstract

A watercraft includes a ship body; a main propulsion device including a jet pump that jets a jet water flow from the ship body; and an auxiliary propulsion device including a propeller disposed in a tunnel penetrating the ship body in a ship width direction and an electric motor that rotationally drives the propeller. The electric motor has a motor shaft extending on a plane orthogonal to an up-down direction of the ship body.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to Japanese Patent Application No. 2025-027945, filed on Feb. 25, 2025, the entire disclosure of which is incorporated herein by reference.FIELD OF INVENTION

[0002] The present disclosure relates to a watercraft.BACKGROUND ART

[0003] As a watercraft propelled by a jet water flow, a watercraft described in US 2013 / 0102206 A is known.

[0004] Such a watercraft as described above is demanded to have high stability during sliding.SUMMARY OF THE INVENTION

[0005] An object of the present disclosure is to provide a watercraft having high stability during sliding.

[0006] In order to solve the above problem, a watercraft according to one aspect of the present disclosure includes: a ship body; a main propulsion device including a jet pump that jets a jet water flow from the ship body; and an auxiliary propulsion device including a propeller disposed in a tunnel penetrating the ship body in a ship width direction that is a width direction of the ship body, and an electric motor that rotationally drives the propeller, the electric motor having a motor shaft extending on a plane orthogonal to an up-down direction of the ship body.

[0007] A watercraft according to another aspect of the present disclosure includes: a ship body; a main propulsion device that includes a main prime mover and applies at least a forward propulsive force to the ship body on the basis of power of the main prime mover; and an auxiliary propulsion device that includes an auxiliary prime mover and applies, to the ship body, a propulsive force in a direction different from the propulsive force applied by the main propulsion device on the basis of power of the auxiliary prime mover, the auxiliary prime mover being disposed in an attitude of having a longitudinal direction extending on a plane orthogonal to an up-down direction of the ship body.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a partially broken side view of a personal watercraft according to an embodiment of the present disclosure;

[0009] FIG. 2 is a plan view of the personal watercraft as viewed from above;

[0010] FIG. 3 is a schematic front view of the personal watercraft as viewed from the front;

[0011] FIG. 4 is a side cross-sectional view illustrating a front part of the personal watercraft in a partially broken state;

[0012] FIG. 5 is a view schematically illustrating an operation mode of the personal watercraft;

[0013] FIG. 6 is a perspective view of an auxiliary propulsion device;

[0014] FIG. 7 is a front view of the auxiliary propulsion device as viewed from the front;

[0015] FIG. 8 is a cross-sectional view, corresponding to FIG. 7, of the auxiliary propulsion device;

[0016] FIG. 9 is a side view of the auxiliary propulsion device as viewed from the right;

[0017] FIG. 10 is a side view of the auxiliary propulsion device as viewed from the left;

[0018] FIG. 11 is a view equivalent to FIG. 8, illustrating a first modification of the present disclosure; and

[0019] FIG. 12 is a view equivalent to FIG. 7, illustrating a second modification of the present disclosure.DETAILED DESCRIPTIONOverall Configuration of Personal Watercraft

[0020] FIG. 1 is a partially broken side view of a watercraft 1 according to an embodiment of the present disclosure, FIG. 2 is a plan view of the watercraft 1 as viewed from above, and FIG. 3 is a schematic front view of the watercraft 1 as viewed from the front. In the present embodiment, the watercraft 1 is a jet propulsion and riding type personal watercraft that jets a water flow to move over the water in reaction thereto. The watercraft 1 includes a ship body 10, a main propulsion device 2, and an auxiliary propulsion device 3. Hereinafter, the watercraft 1 will be appropriately abbreviated as a PWC1.

[0021] Here, front, rear, left, right, up, and down directions displayed in each figure are based on a driver M (FIG. 1) riding in the PWC1. In addition, a front-rear direction, a left-right direction, and an up-down direction of the PWC1 or the ship body 10 are defined on the basis of these respective directions. Namely, the front-rear direction is a direction along a longitudinal direction of the ship body 10, where a bow side is the front and a stern side is the rear. In a state where the PWC1 is in a stationary state and no passengers and luggage are placed on the PWC1, the front-rear direction can be defined as a direction extending parallel to the longitudinal direction of the ship body 10 along a horizontal plane. The left-right direction is a direction orthogonal to the front-rear direction and parallel to a ship width direction which is a width direction of the ship body 10, and a left hand side of the driver M is the left and a right hand side is the right. The up-down direction is a direction orthogonal to the front-rear direction and the left-right direction (ship width direction), and a side facing the top is an upper side and a side opposite thereto (a side facing underwater) is a lower side. In a state where the PWC1 is in the stationary state and no passengers and luggage are placed on the PWC1, the up-down direction can be defined as a direction parallel to a vertical line.

[0022] The ship body 10 includes a hull 11 constituting a lower part of the ship body 10, and a deck 12 disposed on an upper side of the hull 11. An upper surface of the hull 11 is opened. The deck 12 covers an upper surface opening of the hull 11 and is joined to an opening edge of the hull 11 over the entire circumference. Namely, a gunnel 10G which is a joining line between the hull 11 and the deck 12 is formed on a peripheral edge of the ship body 10.

[0023] A steering handle 13 and a seat 14 are disposed on the deck 12. The steering handle 13 is attached to a front part of the deck 12. The steering handle 13 includes, for example, a handlebar that is turnable around an axis extending in a substantially up-down direction and extends in the ship width direction (left-right direction), and a throttle lever for speed adjustment attached to one end part of the handlebar. The seat 14 is disposed behind the steering handle 13 so as to cover a region including a central part of the deck 12. The seat 14 may be a seat on which at least the driver M can sit. Namely, the seat 14 may be a seat for plural persons on which not only the driver M but also fellow passengers can sit, or may be a seat for one person on which only the driver M can sit.

[0024] FIG. 4 is a side cross-sectional view illustrating a front part of the PWC1 in a partially broken state. As illustrated in this figure, a luggage room 6 is built in a front part of the ship body 10. The luggage room 6 functions as a storage for storing luggage and the like of crew members including the driver M, and is defined by a box-shaped luggage room wall 61. The luggage room 6 or the luggage room wall 61 is disposed in a space between the hull 11 and the deck 12 at the front part of the ship body 10 so as to occupy most of the space. The luggage room 6 corresponds to a “storage” in the present disclosure.

[0025] A power room ER is formed behind the luggage room 6. The power room ER is defined between the hull 11 and the deck 12, and is formed to extend in the front-rear direction from the front part to a central part of the ship body 10. A fuel tank 23 is disposed at a front part of the power room ER and immediately behind the luggage room 6. The fuel tank 23 is a tank that accumulates fuel to be supplied to a power source (an engine 21 to be described later) of the main propulsion device 2.

[0026] A front hatch 16 is attached to a front part of the deck 12. The front hatch 16 is a lid that openably covers the luggage room 6. Namely, a luggage room opening A1 for loading and unloading luggage is formed on an upper surface of the luggage room wall 61, and the front hatch 16 is attached to the front part of the deck 12 so as to cover the luggage room opening A1 from above. A front end part of the front hatch 16 is pivotally supported by the deck 12 via a hinge 16H, whereby the front hatch 16 is attached so as to be turnable in the up-down direction around the hinge 16H as indicated by an arrow Y1 in FIG. 4. Namely, the front hatch 16 is attached to the deck 12 so as to be changeable between a closed state indicated by a solid line and an open state indicated by a dashed line in FIG. 4.

[0027] As illustrated in FIGS. 1 and 2, the main propulsion device 2 includes the engine 21 as a power source and a jet pump 4 that generates a jet water flow. As also illustrated in FIG. 4, the engine 21 is housed behind the fuel tank 23 in the power room ER. The engine 21 is disposed near the center of the ship body 10 in the front-rear direction. The jet pump 4 is disposed in a rear part of the ship body 10.

[0028] The engine 21 is an internal combustion engine. The engine 21 generates power for driving the jet pump 4. The engine 21 is, for example, a water-cooled 4-stroke multi-cylinder engine driven using gasoline as fuel. The engine 21 includes a crankshaft 22 extending in the front-rear direction as an output shaft. The engine 21 corresponds to a “main prime mover” in the present disclosure.

[0029] The jet pump 4 is disposed behind the engine 21 and includes an impeller shaft 41 and an impeller 42. The impeller shaft 41 extends in the front-rear direction behind the crankshaft 22 and is coaxially connected to the crankshaft 22. When the crankshaft 22 rotates around the axis by driving of the engine 21, a rotational driving force is applied to the impeller shaft 41. The impeller 42 is attached to a rear end of the impeller shaft 41. The impeller 42 rotates around the axis to generate a jet water flow.

[0030] The ship body 10 includes an impeller passage 47 in which the jet pump 4 is disposed. The impeller passage 47 includes a water inlet 48 for taking in water (e.g., sea water) in a water landing zone of the PWC1. The water inlet 48 is formed at the center of a rear part bottom surface of the hull 11 in the ship width direction. The impeller passage 47 is formed so as to penetrate the rear part of the hull 11 in the front-rear direction. In order to apply a propulsive force to the PWC1, the jet pump 4 pressurizes and accelerates the water taken into the impeller passage 47 and jets the water rearwards.

[0031] The jet pump 4 further includes a venturi nozzle 43, a jet nozzle 44, and a reverse bucket 46. The venturi nozzle 43 and the jet nozzle 44 accelerate the water sent from the impeller 42 to generate a jet water flow. The venturi nozzle 43 is disposed behind the impeller passage 47 and has a flow path cross-sectional area that gradually decreases rearwards to increase a flow velocity. The jet nozzle 44 has an jet port 45 that opens backwards as an outlet for a jet water flow. The jet nozzle 44 is connected to a rear end part of the venturi nozzle 43 so as to be swingable left and right around an axis extending in the up-down direction. The jet nozzle 44 is driven to swing by a nozzle motor 44M. When the jet nozzle 44 swings, a jet direction of the jet water flow from the jet port 45 is changed to the left and right. The nozzle motor 44M is driven, for example, according to the steering of the steering handle 13.

[0032] The jet nozzle 44 may be attached so as to be swingable up and down around an axis extending in the ship width direction (left-right direction). Such an up-down direction swinging function of the jet nozzle 44 enables adjustment of a sliding attitude of the PWC1. For example, the more the jet nozzle 44 is inclined downward by swinging, the more a height of the bow of the PWC1 in a sliding state can be increased.

[0033] The reverse bucket 46 has a function of switching a propulsion direction of the PWC1 forwards or rearwards. The reverse bucket 46 is disposed in the vicinity of the jet port 45, and is attached to the jet nozzle 44 so as to be turnable around an axis extending in the left-right direction. When the reverse bucket 46 descends so as to cover the jet port 45, the jet water flow is redirected forwards, and the propulsion direction of the PWC1 is changed rearwards.

[0034] The auxiliary propulsion device 3 generates a water flow in the ship width direction (left-right direction), i.e., a water flow directed leftwards or rightwards from the front part of the ship body 10. This water flow imparts a propulsive force in the ship width direction to the ship body 10. Although the present embodiment shows an example in which a water flow is jetted straight in the ship width direction from the auxiliary propulsion device 3, the water flow may be a water flow in a direction inclined with respect to the ship width direction.

[0035] The ship body 10 includes a tunnel 5 at a position corresponding to the auxiliary propulsion device 3. The tunnel 5 is a passage extending so as to linearly penetrate the hull 11 in the ship width direction at the front part of the ship body 10. The tunnel 5 is defined by a tunnel wall 50 (FIG. 4) which is a cylindrical wall extending in the ship width direction. The tunnel 5 has an opening at each of opposite ends of the tunnel 5. As illustrated in FIGS. 2 and 3, a first tunnel opening 5A is opened at one end of the tunnel 5, and a second tunnel opening 5B is opened at the other end. The first tunnel opening 5A opens on a left side surface of a front part of the hull 11. The second tunnel opening 5B opens on a right side surface of the front part of the hull 11. The first tunnel opening 5A and the second tunnel opening 5B are formed ahead of the engine 21 and the jet pump 4.

[0036] The tunnel 5 is disposed ahead of the steering handle 13 and the fuel tank 23. Namely, the tunnel 5 is disposed between the steering handle 13 (or the fuel tank 23) and the bow in the front-rear direction.

[0037] In addition, the first tunnel opening 5A and the second tunnel opening 5B of the tunnel 5 are located below a water surface at least when the PWC1 is stationary or in a non-sliding state of moving at a slow speed. In other words, the tunnel openings 5A and 5B are located at a height close to a ship bottom. For example, upper ends of the tunnel openings 5A and 5B are located below upper ends of the engine 21 and the fuel tank 23. As a result, since a height of the tunnel 5 becomes relatively low, components such as an electric motor 51 to be described later can be easily disposed above the tunnel 5.

[0038] On the other hand, when the PWC1 is in the sliding state, the tunnel openings 5A and 5B can be located above the water surface. When the tunnel openings 5A and 5B are located above the water surface, the tunnel openings 5A and 5B are prevented from becoming resistive elements at the time of sliding.

[0039] The auxiliary propulsion device 3 discharges fluid from the inside of the tunnel 5 to the outside of the ship body 10 through the first tunnel opening 5A or the second tunnel opening 5B, and by a reaction force thereof, generates the propulsive force in the ship width direction. Although the discharged fluid is basically water (e.g., sea water) in the water landing zone of the PWC1, the fluid may contain air. In the present specification, a flow of the fluid discharged from the tunnel 5 in this manner is simply referred to as a water flow.

[0040] As illustrated mainly in FIG. 3, the auxiliary propulsion device 3 includes the electric motor 51, a propeller 52, and a gear mechanism 53. The electric motor 51 is a power source for obtaining the propulsive force in the ship width direction, and rotationally drives the propeller 52. The electric motor 51 may be an AC motor or a DC motor. The propeller 52 is disposed in the tunnel 5 and rotates in the tunnel 5. The gear mechanism 53 transmits a driving force of the electric motor 51 to the propeller 52. Namely, when the electric motor 51 is driven, power of the electric motor 51 is transmitted to the propeller 52 via the gear mechanism 53, so that the propeller 52 rotates. Rotation of the propeller 52 generates a water flow in the tunnel 5, and discharge of the water flow generates the propulsive force in the ship width direction. The electric motor 51 corresponds to an “auxiliary prime mover” in the present disclosure, and the gear mechanism 53 corresponds to a “power transmission mechanism” in the present disclosure.

[0041] FIG. 5 is a view schematically illustrating an operation mode of the PWC1. In FIG. 5, two operation modes of sliding and turning are illustrated. In the sliding mode, the main propulsion device 2 is activated and jets a jet water flow backwards from the jet pump 4, as indicated by an arrow F1. The PWC1 moves forwards as indicated by an arrow D1 upon receiving a forward propulsive force applied to the rear part of the ship body 10 due to a reaction of the jet water flow. When the reverse bucket 46 is activated to cover the jet port 45, the PWC1 is propelled backwards.

[0042] In addition, in the sliding mode, it is possible to revolve the PWC1 by the steering of the steering handle 13. Namely, a direction of the jet water flow is changed to either the left or right by leftward or rightward swinging of the jet nozzle 44 accompanying the steering of the steering handle 13, and the PWC1 revolves accordingly. For example, in a case where the jet nozzle 44 is swung rightwards by the steering handle 13, a jet water flow is jetted diagonally rearwards to the right as indicated by an arrow F1A. As indicated by an arrow D1A, the PWC1 revolves rightwards upon receiving a left diagonal forward propulsive force applied to the rear part of the ship body 10 due to the reaction of the jet water flow. Conversely, when the jet nozzle 44 is swung leftwards, the PWC1 revolves leftwards. During such revolution, while straddling the seat 14, the driver M may perform manipulation of inclining the ship body 10 around an axis extending in the front-rear direction, i.e., manipulation of banking the ship body 10 to either the left or the right by his / her weight movement in order to resist a centrifugal force accompanying the revolution.

[0043] In the turning mode, the main propulsion device 2 is deactivated and the auxiliary propulsion device 3 is activated, thereby causing the PWC1 to stationarily turn. For example, as indicated by an arrow F2 in FIG. 5, when the auxiliary propulsion device 3 is activated so that a water flow is discharged leftwards from the first tunnel opening 5A, a reaction of the water flow causes application of a rightward propulsive force to the front part of the ship body 10. Upon receiving this propulsive force, as indicated by an arrow D2, the PWC1 turns clockwise around a center of gravity G thereof. Conversely, when the auxiliary propulsion device 3 is activated so that the water flow is discharged rightwards from the second tunnel opening 5B, a leftward propulsive force is applied to the front part of the ship body 10, so that the PWC1 turns counterclockwise.

[0044] Although not illustrated in FIG. 5, an operation mode in which both the main propulsion device 2 and the auxiliary propulsion device 3 are activated may be set separately from the sliding mode and the turning mode.Details of Auxiliary Propulsion Device

[0045] Details of the auxiliary propulsion device 3 will be further described. FIG. 6 is a perspective view of the auxiliary propulsion device 3, FIG. 7 is a front view of the auxiliary propulsion device 3 as viewed from the front, FIG. 8 is a cross-sectional view corresponding to the auxiliary propulsion device 3 in FIG. 7, FIG. 9 is a side view of the auxiliary propulsion device 3 as viewed from the right, and FIG. 10 is a side view of the auxiliary propulsion device 3 as viewed from the left. As illustrated in each drawing, the electric motor 51 is disposed outside the tunnel 5 near the center in a ship width direction (left-right direction) of the tunnel 5. In the present embodiment, the electric motor 51 is disposed above the tunnel 5, and is opposed to an upper surface of the tunnel wall 50 with a slight distance.

[0046] The electric motor 51 includes a tubular motor case 511, an electric unit 512 including electromagnetic components such as a rotor and a stator housed inside the motor case 511, and a motor shaft 513 extending from the electric unit 512 to the outside of the motor case 511.

[0047] The motor shaft 513 extends in the ship width direction. Namely, the electric motor 51 is disposed in an attitude in which the motor shaft 513 extends in the ship width direction, in other words, in an attitude in which the motor shaft 513 extends on a plane orthogonal to the up-down direction. An extending direction of the motor shaft 513 is parallel to a tunnel axis which is a central axis of the tunnel 5. The motor shaft 513 has one end part fixed to the above rotor of the electric unit 512. In the present embodiment, a right end part of the motor shaft 513 extending in the ship width direction (left-right direction) is fixed to the rotor, and the motor shaft 513 extends leftwards from the electric unit 512 toward the outside of the motor case 511. A part of the motor shaft 513 extending to the outside of the motor case 511 is inserted inside an upper part (a first case part 531a to be described later) of the gear mechanism 53. When the electric motor 51 is driven, the above rotor rotates with respect to the above stator by energization, and the motor shaft 513 rotates integrally with the rotor.

[0048] The electric motor 51 has a shape elongated in a longitudinal direction such that the ship width direction (left-right direction), which is the extending direction of the motor shaft 513, becomes the longitudinal direction. Namely, the electric motor 51 is disposed such that its longitudinal direction extends on a plane orthogonal to the up-down direction.

[0049] The propeller 52 includes an impeller 521 rotatable in the tunnel 5, and a propeller shaft 522 (rotation shaft) coaxially coupled to the impeller 521.

[0050] The propeller shaft 522 extends in the ship width direction in the tunnel 5. Namely, the propeller 52 is disposed in an attitude in which the propeller shaft 522 extends in the ship width direction, in other words, in an attitude in which the propeller shaft 522 extends on the plane orthogonal to the up-down direction. The propeller shaft 522 is disposed at the center of the tunnel 5, i.e., at the center of a circular cross section of the tunnel 5.

[0051] The impeller 521 has a boss 521a fixed to one end part of the propeller shaft 522, and a plurality of vanes 521b extending radially outward from a peripheral surface of the boss 521a. In the present embodiment, the propeller shaft 522 is disposed so as to protrude rightwards from the inside of a lower part (a second case part 531b to be described later) of the gear mechanism 53 disposed in the tunnel 5, and the boss 521a of the impeller 521 is fixed to a right end part of the propeller shaft 522. The propeller shaft 522 rotates upon reception of a rotational force transmitted from the electric motor 51 via the gear mechanism 53. The impeller 521 rotates integrally with the propeller shaft 522 to generate a water flow.

[0052] Here, as described above, in the present embodiment, both the motor shaft 513 and the propeller shaft 522 extend in the ship width direction. Namely, the electric motor 51 and the propeller 52 are disposed such that the motor shaft 513 and the propeller shaft 522 are parallel to each other. Alternatively, the electric motor 51 is disposed in an attitude of having its longitudinal direction parallel to the propeller shaft 522.

[0053] As mainly illustrated in FIG. 8, the gear mechanism 53 has a gear case 531, and a first gear 532 and a second gear 533 housed in the gear case 531.

[0054] The first gear 532 is externally fitted to the motor shaft 513 so as to rotate integrally with the motor shaft 513. The second gear 533 is externally fitted to the propeller shaft 522 so as to rotate integrally with the propeller shaft 522. Each of the first gear 532 and the second gear 533 is a spur gear in which a large number of linear teeth are formed on an outer peripheral surface. Both the gears 532 and 533 are meshed so as to rotate in conjunction with each other.

[0055] Although the gear mechanism 53 may function as either a speed reducer or a speed booster, in the present embodiment, the gear mechanism 53 functions as a speed booster. Namely, an outer diameter of the first gear 532 is larger than an outer diameter of the second gear 533. When rotation of the first gear 532 is transmitted to the second gear 533, the second gear 533 rotates at a speed higher than that of the first gear 532. Namely, the gear mechanism 53 in the present embodiment accelerates the rotation of the motor shaft 513 and transmits the rotation to the propeller shaft 522.

[0056] The gear case 531 has a first case part 531a that houses the first gear 532 and a second case part 531b that houses the second gear 533. The second case part 531b is disposed in the tunnel 5. The second case part 531b has a substantially circular shape as viewed in the ship width direction, and has an outer diameter smaller than a diameter of the tunnel 5. The first case part 531a has a circular shape having an outer diameter larger than that of the second case part 531b as viewed in the ship width direction, and is continuous with an upper part of the second case part 531b. The first case part 531a has a most part of an upper side thereof located outside the tunnel 5, and a part of a lower side thereof entering the inside of the tunnel 5 to be continuous with the second case part 531b.

[0057] A bearing 535 that rotatably supports the motor shaft 513 is disposed inside the first case part 531a. A bearing 536 that rotatably supports the propeller shaft 522 is disposed inside the second case part 531b.

[0058] The gear case 531 has a first fixing part 531c functioning as a fixing part to the electric motor 51 and a second fixing part 531d functioning as a fixing part to the tunnel wall 50. The first fixing part 531c is formed in a tubular shape protruding rightwards from the first case part 531a toward the electric motor 51. The first fixing part 531c and the motor case 511 are coupled to each other with a bolt or the like via a flange 55. The second fixing part 531d is formed in a rectangular frame shape as viewed in the up-down direction so as to surround a lower part of the first case part 531a. The second fixing part 531d is fixed to a pedestal 50a formed at a central part of the tunnel wall 50 in the ship width direction in a state of being placed on an upper surface of the pedestal 50a. The pedestal 50a has a shape similar to an arch-shaped gate, and is formed so as to protrude radially outward from an upper half part of the central part of the tunnel wall 50. On the upper surface of the pedestal 50a, an opening is formed which has a rectangular shape as viewed in the up-down direction corresponding to an opening on a lower surface of the second fixing part 531d. The second fixing part 531d is joined to the pedestal 50a from above by an appropriate means such as welding. As a result, the gear case 531 is fixed to the tunnel wall 50 in a state of having a part of a lower side thereof including the second case part 531b entering the tunnel 5.

[0059] As described above, in the present embodiment, the gear case 531 is fixed to the tunnel wall 50, and the motor case 511 is fixed to the gear case 531. Namely, the electric motor 51 is indirectly supported by the tunnel wall 50 via the gear case 531.

[0060] The electric motor 51 and the propeller 52 are disposed on one side of the gear mechanism 53 in the ship width direction (left-right direction). Although the electric motor 51 and the propeller 52 can be disposed on either a left side or a right side of the gear mechanism 53, in the present embodiment, both are disposed on the right side of the gear mechanism 53. For example, the electric motor 51 is disposed on the right side of the gear mechanism 53 by fixing the motor case 511 to an upper part (first case part 531a) of the gear case 531 from the right side. In addition, the propeller 52 is disposed on the right side of the gear mechanism 53 by being supported in a state where the propeller shaft 522 is inserted from the right side into a lower part (the second case part 531b) of the gear case 531.

[0061] When the auxiliary propulsion device 3 is in use, for example, when the auxiliary propulsion device 3 is activated for executing the turning mode shown in FIG. 5, the propeller 52 is rotated by driving of the electric motor 51, so that a water flow is generated in the tunnel 5. Namely, when the motor shaft 513 is rotated by driving of the electric motor 51, the first gear 532 fixed to the motor shaft 513 rotates, and the second gear 533 meshed with the first gear 532 rotates. As a result, the propeller shaft 522 fixed to the second gear 533 rotates, and the impeller 521 fixed to the propeller shaft 522 rotates. The rotation of the impeller 521 generates a water flow in the tunnel 5, and the water flow is discharged from the tunnel 5 toward one of the left and right directions.

[0062] Here, a direction of the water flow discharged from the tunnel 5 is decided by a rotation direction of the motor shaft 513 of the electric motor 51. For example, when the electric motor 51 is driven so that the motor shaft 513 rotates in a predetermined forward rotation direction, the propeller 52 rotates so as to generate a water flow from left to right in the tunnel 5. Namely, as indicated by an open arrow in FIG. 6, the fluid is taken in from the first tunnel opening 5A, and is discharged rightwards from the second tunnel opening 5B. A reaction force caused by the discharge serves as a propulsive force for moving the PWC1 leftwards. On the other hand, when the electric motor 51 is driven so that the motor shaft 513 rotates in a reverse rotation direction opposite to the forward rotation direction, the propeller 52 rotates so that a water flow directed from right to left is generated in the tunnel 5. Namely, conversely to the open arrow in FIG. 6, the fluid is taken in from the second tunnel opening 5B, and is discharged leftwards from the first tunnel opening 5A. A reaction force caused by the discharge serves as a propulsive force for moving the PWC1 rightwards.

[0063] A plane CP illustrated in FIGS. 3, 7, and 8 is a width center plane that divides the ship body 10 into two equal parts in the ship width direction. The width center plane CP is a plane extending in the up-down direction through the center of gravity G of the PWC1, and is orthogonal to the ship width direction. Namely, the width center plane CP coincides with a vertical line passing through the center of gravity G when viewed from the front in a normal state where the ship body 10 is inclined neither to the left nor to the right. The above-described electric motor 51 and propeller 52 in the auxiliary propulsion device 3 are disposed at positions intersecting the width center plane CP.

[0064] Specifically, the electric motor 51 is disposed near the center of the ship body 10 in the ship width direction such that the width center plane CP intersects any part of the electric motor 51. Here, an axis X1 illustrated in FIG. 8 is a motor central axis which is a center of the motor shaft 513, and a direction along the motor central axis X1 is assumed to be an axial direction of the electric motor 51. Here, the axial direction of the electric motor 51 is synonymous with a longitudinal direction of the electric motor 51. In the present embodiment, the electric motor 51 is disposed such that the width center plane CP intersects an axial intermediate position of the electric motor 51. Namely, the width center plane CP is located between a right end of the motor case 511, which is one axial end of the electric motor 51, and a left end of the motor shaft 513, which is the other axial end of the electric motor 51. More specifically, the width center plane CP is located between one end and the other end in an axial direction of the motor case 511. In other words, the electric motor 51 is disposed so as to intersect the width center plane CP at an intermediate position in the axial direction of the motor case 511. More preferably, the electric motor 51 is disposed at a position such that the width center plane CP passes through the center of gravity of the electric motor 51.

[0065] Similarly, the propeller 52 is disposed near the center of the ship body 10 in the ship width direction such that the width center plane CP intersects any part of the propeller 52. Here, an axis X2 illustrated in FIG. 8 is a propeller central axis which is a center of the propeller shaft 522, and a direction along the propeller central axis X2 is assumed to be an axial direction of the propeller 52. In the present embodiment, the propeller 52 is disposed such that the width center plane CP intersects an axial intermediate position of the propeller 52. Namely, the width center plane CP is located between a right end of the impeller 521, which is one end in the axial direction of the propeller52, and a left end of the propeller shaft 522, which is the other end in the axial direction of the propeller 52. More specifically, the width center plane CP is located at a position corresponding to the vane 521b of the impeller 521. In other words, the propeller 52 is disposed so as to intersect the width center plane CP at a position of the vane 521b.

[0066] Here, as described above, the electric motor 51 and the propeller 52 are located at positions intersecting the common width center plane CP. The electric motor 51 is disposed above the tunnel 5, and the propeller 52 is disposed inside the tunnel 5. Namely, the electric motor 51 and the propeller 52 are disposed to have a relationship in which the electric motor 51 is located above the propeller 52 across the tunnel wall 50 near a width center of the ship body 10.

[0067] As illustrated in FIG. 4, the electric motor 51 is disposed between a rear surface of the luggage room wall 61 (luggage room 6) and a front surface of the fuel tank 23 in a side view. In other words, the ship body 10 has, between the luggage room wall 61 and the fuel tank 23, a motor housing part S1 for housing the electric motor 51.

[0068] The luggage room wall 61 has a shielding part 61a that covers the electric motor 51 from above. The shielding part 61a is formed with an access opening A2 for enabling access to the electric motor 51 at the time of maintenance of the auxiliary propulsion device 3. A lid member 62 for closing the access opening A2 is detachably attached to the luggage room wall 61. Namely, at the time of maintenance of the auxiliary propulsion device 3, an operator opens the front hatch 16 and removes the lid member 62. As a result, the electric motor 51 can be accessed from the outside through the luggage room opening A1 and the access opening A2. Namely, in the present embodiment, in order to secure accessibility to the electric motor 51 even in a case where the luggage room 6 exists above the electric motor 51, the electric motor 51 is housed in the motor housing part S1 with the access opening A2.

[0069] Although not illustrated in the drawings, a battery that accumulates electric power supplied to the electric motor 51 can be disposed in the vicinity of the electric motor 51. For example, the batteries may be disposed side by side with the electric motor 51 in an axial direction of the tunnel 5, i.e., in the ship width direction. Alternatively, the battery may be disposed at a position lower than an upper end of the electric motor 51 and behind the tunnel 5.Operation and Effects

[0070] As described in the foregoing, in the present embodiment, the electric motor 51, which is the power source of the auxiliary propulsion device 3, is disposed in the attitude in which the motor shaft 513 extends in the ship width direction. Therefore, as compared with a case where the motor shaft 513 extends in the up-down direction, stability at the time of sliding of the PWC1 can be improved.

[0071] Namely, in the present embodiment, since the electric motor 51 is disposed in the attitude in which the motor shaft 513 extends in the ship width direction, i.e., in the attitude in which the motor shaft 513 extends on a plane orthogonal to the up-down direction, an upper end position of the electric motor 51, which is a heavy object, can be suppressed to be low as compared with a case where the electric motor 51 is disposed in the attitude in which the motor shaft 513 extends in the up-down direction. As a result, the center of gravity G of the PWC1 can be kept low, so that the stability of the PWC1 during sliding can be improved. Furthermore, since the stability is improved, operability of the PWC1 can be improved.

[0072] Here, in the PWC1, a width dimension, which is a dimension in the left-right direction of the ship body 10, is significantly smaller than a length dimension, which is a dimension in the front-rear direction of the ship body 10. Namely, in the PWC1, a ratio of the width dimension to the length dimension of the ship body 10 is often smaller than that of a common ship. Therefore, the PWC1 tends to roll side-to-side due to an influence of waves and wind on the water. By contrast, according to the present embodiment in which the center of gravity G of the PWC1 is suppressed to be low, it is possible to reduce ease of side-to-side rolling of the PWC1, and it is also possible to improve the stability of the PWC1 in that sense.

[0073] In addition, although in the PWC1, the driver M may perform manipulation to bank the ship body 10 to either the left or the right by moving his / her weight during the revolution, such banking manipulation may not be easy particularly for a beginner. By contrast, according to the present embodiment in which the center of gravity G of the PWC1 is suppressed to be low, since an excessive attitude change of the PWC1 due to the banking manipulation is suppressed, the banking manipulation can be facilitated, and the operability of the PWC1 can be improved in that sense as well.

[0074] Furthermore, at the time of forward movement using the main propulsion device 2, as a moving speed increases, the PWC1 makes a state transition to the sliding state in which the ship moves sliding on the water surface with the bow lifting up from the water. In this case, according to the present embodiment in which the center of gravity G of the PWC1 is suppressed to be low, the bow is likely to lift up from the water surface, so that the shift of the PWC1 to the sliding state can be promoted.

[0075] Moreover, since the motor shaft 513 extends in the ship width direction, the electric motor 51 can be disposed along the tunnel 5. As a result, an amount by which the electric motor 51 protrudes in a radial direction around the central axis (tunnel axis) of the tunnel 5 with respect to the tunnel 5 can be reduced. In particular, in a case where the electric motor 51 is disposed above the tunnel 5 as in the present embodiment, an amount of protrusion of the electric motor 51 in the front-rear direction with respect to the tunnel 5 can be reduced. In other words, according to the present embodiment in which the electric motor 51 is disposed such that the motor shaft 513 extends parallel to the tunnel shaft, the auxiliary propulsion device 3 including the electric motor 51 can be made compact in the radial direction (or the front-rear direction) of the tunnel 5.

[0076] Furthermore, in the present embodiment, the electric motor 51 and the propeller 52 are disposed at positions intersecting the width center plane CP which is a common perpendicular plane orthogonal to the ship width direction. In other words, the electric motor 51 and the propeller 52 are disposed in a layout in which a power transmission path from the electric motor 51 to the propeller 52 is folded back in a U shape. According to such a configuration, since the electric motor 51 and the propeller 52 are disposed at positions close to each other in the ship width direction, a dimension of the auxiliary propulsion device 3 in the ship width direction can be reduced as compared with a case where the power transmission path has a non-U shape.

[0077] Moreover, since the width center plane CP is a plane that divides the ship body 10 into two equal parts in the ship width direction, disposing the electric motor 51 at a position intersecting the width center plane CP realizes a layout in which the electric motor 51 as a heavy object is located near the width center of the ship body 10. As a result, the center of gravity G of the PWC1 can be easily brought closer to the width center of the ship body 10 to improve a weight balance between the left and the right of the PWC1.

[0078] Furthermore, since the propeller 52 is disposed at a position intersecting the width center plane CP, i.e., the propeller 52 is disposed near the center in the ship width direction in the tunnel 5, in either case where the direction of the water flow caused by the rotation of the propeller 52 is set to the left or the right, the same propulsive force can be easily exerted to improve usability of the auxiliary propulsion device 3.

[0079] In the present embodiment, both the motor shaft 513 and the propeller shaft 522 extend in the ship width direction and are disposed in parallel with each other. According to such a configuration, for example, unlike a case where the motor shaft 513 and the propeller shaft 522 are not parallel, such as a case where the motor shaft 513 is disposed to extend in the front-rear direction, a structure of the gear mechanism 53 that links the motor shaft 513 and the propeller shaft 522 can be simplified.

[0080] In addition, in the present embodiment, the electric motor 51 is disposed above the propeller 52 (tunnel 5). According to such a configuration, a dimension in the front-rear direction of the auxiliary propulsion device 3 can be reduced as compared with a case where the electric motor 51 is disposed ahead of or behind the propeller 52. In addition, as compared with a case where the electric motor 51 is disposed below the propeller 52, i.e., between the tunnel 5 and the ship bottom, the tunnel 5 can be easily brought close to the ship bottom, and the tunnel openings 5A and 5B can be easily disposed below the water surface at the time of non sliding of the PWC1.

[0081] Also in the present embodiment, the gear mechanism 53 that transmits the rotation of the motor shaft 513 to the propeller shaft 522 is provided, and the electric motor 51 and the propeller 52 are both disposed on the right side of the gear mechanism 53. Thus, in a case where the electric motor 51 and the propeller 52 are disposed on the same side in the ship width direction with respect to the gear mechanism 53, the dimension in the ship width direction of the auxiliary propulsion device 3 can be reduced as compared with the case where they are disposed on the opposite sides with the gear mechanism 53 interposed therebetween.

[0082] In addition, in the present embodiment, the gear mechanism 53 functions as a speed booster that accelerates the rotation of the motor shaft 513 and transmits the rotation to the propeller shaft 522. According to such a configuration, even in a case where the electric motor 51 is relatively small or low output, by transmitting the rotation of the electric motor 51 to the propeller 52 via the gear mechanism 53 (speed booster), the propeller 52 can be rotated at a rotation speed at which a propulsive force that can move the PWC1 is generated.

[0083] In the present embodiment, the electric motor 51 is indirectly supported by the tunnel wall 50 constituting the tunnel 5 via the gear case 531. Thus, in a case where the electric motor 51 is supported using the tunnel wall 50, the structure of the auxiliary propulsion device 3 can be simplified.

[0084] In the present embodiment, the luggage room 6 is disposed above the electric motor 51. Thus, in a case where the luggage room 6 is disposed above the electric motor 51 whose upper end position is suppressed to be low, a capacity of the luggage room 6 can be sufficiently secured.

[0085] Furthermore, in the luggage room wall 61 constituting the luggage room 6, the access opening A2 that enables external access to the electric motor 51 is formed in the shielding part 61a that covers the electric motor 51 from above. According to such a configuration, the electric motor 51 can be easily accessed through the access opening A2 at the time of maintenance of the auxiliary propulsion device 3, and maintainability can be improved.Modification

[0086] Although the preferred embodiment of the present disclosure has been described in the foregoing, the present disclosure is not limited thereto, and for example, the following modifications are possible.

[0087] Although in the above embodiment, the gear mechanism 53 including the first gear 532 and the second gear 533 meshed with each other is used as the power transmission mechanism that transmits the rotation of the motor shaft 513 to the propeller shaft 522, the configuration of the power transmission mechanism is not limited thereto. For example, one or more relay gears may be provided between the first gear 532 and the second gear 533. Instead of the above embodiment in which the outer diameter of the first gear 532 is larger than the outer diameter of the second gear 533, the outer diameter of the first gear 532 may be smaller than the outer diameter of the second gear 533. Namely, the gear mechanism 53 may function as a speed reducer instead of a speed booster.

[0088] Furthermore, a power transmission mechanism using a mechanism other than gears may be used. For example, as illustrated in FIG. 11, a power transmission mechanism 73 including a chain or a belt may be used. Specifically, the power transmission mechanism 73 illustrated in FIG. 11 includes a first pulley 732 fixed to the motor shaft 513, a second pulley 733 fixed to the propeller shaft 522, an endless transmission member 734 formed of a chain or a belt wound between the first pulley 732 and the second pulley 733, and a gear case 731 housing these elements 732, 733, and 734. Even when such power transmission mechanism 73 is used, the rotation of the motor shaft 513 can be appropriately transmitted to the propeller shaft 522. Moreover, since outer diameters of the first pulley 732 and the second pulley 733 are easily reduced, an upper end position of the gear case 731 can be suppressed to be low as compared with the above embodiment, and a dimension of the up-down direction of the auxiliary propulsion device 3 can be advantageously reduced.

[0089] In the above embodiment, both the electric motor 51 and the propeller 52 are disposed at the positions intersecting the width center plane CP that divides the ship body 10 into two equal parts in the ship width direction. However, at least one of the electric motor 51 and the propeller 52 may be disposed at a position not intersecting the width center plane CP, i.e., at a position away from the width center plane CP in the ship width direction.

[0090] Although in the above embodiment, the electric motor 51 is disposed outside the luggage room 6, the electric motor 51 may be disposed inside the luggage room 6.

[0091] Although the above embodiment has been described with respect to the example in which the electric motor 51 and the propeller 52 are disposed on one side of the gear mechanism 53 in the ship width direction, the electric motor 51 and the propeller 52 may be disposed on the opposite sides in the ship width direction with the gear mechanism 53 interposed therebetween. For example, as illustrated in FIG. 12, the electric motor 51 may be disposed on the left side of the gear mechanism 53, and the propeller 52 may be disposed on the right side of the gear mechanism 53. As a matter of course, a positional relationship between the electric motor 51 and the propeller 52 can be made reverse to that in FIG. 12.

[0092] Although in the above embodiment, the electric motor 51 is indirectly supported by the tunnel wall 50 via the gear case 531, the electric motor 51 may be directly supported by the tunnel wall 50.

[0093] In the above embodiment, the axial direction or the longitudinal direction of the electric motor 51 is parallel to the ship width direction (left-right direction). However, the axial direction or the longitudinal direction of the electric motor 51 only needs to be a direction extending on a plane orthogonal to the up-down direction of the ship body 10, and is not necessarily parallel to the ship width direction. For example, the axial direction or the longitudinal direction of the electric motor 51 may be parallel to the front-rear direction or may be a direction intersecting the front-rear direction and the ship width direction. In other words, the motor shaft 513 need not be parallel to the propeller shaft 522, but may be non-parallel to the propeller shaft 522. Even in a case where the two are not parallel to each other, when a mechanism including, for example, a bevel gear is used as the gear mechanism 53, the rotation of the motor shaft 513 can be transmitted to the propeller shaft 522 through the mechanism without any trouble.

[0094] Although the above embodiment has been described with respect to the example in which the electric motor 51 is disposed above the propeller 52 and outside the tunnel 5, the electric motor may be disposed coaxially with the propeller shaft 522. Namely, in the tunnel 5, the motor shaft and the propeller shaft may be disposed on the same axis extending in the ship width direction. In addition, the propeller shaft may be directly coupled to the rotor of the electric motor. Furthermore, the propeller 52 may be rotated by a ring-shaped electric motor (hollow motor) disposed in the tunnel 5.

[0095] Although the above embodiment shows the example in which the propeller 52 is rotated by one electric motor 51, a plurality of electric motors 51 may be used. For example, a forward rotation electric motor and a reverse rotation electric motor may be prepared.

[0096] Although in the above embodiment, the electric motor 51 is disposed above the propeller 52 (tunnel 5), the electric motor 51 may be disposed below the propeller 52.

[0097] Furthermore, the electric motor 51 may be disposed ahead of or behind the propeller 52 (tunnel 5). In a case where the electric motor 51 is disposed behind the propeller 52, the position of the center of gravity G of the PWC1 relatively approaches the stern, so that a moment of inertia required to lift the bow from the water surface is reduced, resulting in promoting the PWC1 to make a transition to the sliding state.

[0098] Although the above embodiment has been described with respect to the example in which the main prime mover that is the power source of the main propulsion device 2 is the internal combustion engine 21, the type of the main prime mover is not limited thereto. For example, the main prime mover may be an electric motor.

[0099] Although the above embodiment has been described with respect to the example in which the auxiliary prime mover that is the power source of the auxiliary propulsion device 3 is the electric motor 51, the type of the auxiliary prime mover is not limited thereto. For example, the auxiliary prime mover may be an internal combustion engine, or may be a fluid motor that rotates upon receiving a supply of fluid.

[0100] The above embodiment has been described with respect to the example in which the present disclosure is applied to the personal watercraft (PWC) 1 that is a jet propulsion and riding type personal watercraft. However, a watercraft to which the present disclosure can be applied is not limited to a personal watercraft as long as the watercraft can move on water in a sliding state. For example, the present disclosure can also be applied to a watercraft that obtains a propulsive force by a method other than jet water flow jetting, e.g., by rotation of a propeller, and to a watercraft that performs steering using a steering wheel instead of a steering handle.

[0101] Although the above embodiment has been described with respect to the example in which the present disclosure is applied to the PWC1 including the luggage room 6 provided in the front part of the ship body 10, the present disclosure is naturally applicable to a watercraft in which the luggage room 6 is omitted.Conclusion

[0102] The above embodiment and modifications thereof include the following disclosure.

[0103] A watercraft according to a first aspect of the present disclosure includes: a ship body; a main propulsion device including a jet pump that jets a jet water flow from the ship body; and an auxiliary propulsion device including a propeller disposed in a tunnel penetrating the ship body in a ship width direction that is a width direction of the ship body, and an electric motor that rotationally drives the propeller. The electric motor has a motor shaft extending on a plane orthogonal to an up-down direction of the ship body.

[0104] According to the first aspect, by disposing the electric motor for the auxiliary propulsion device so as to have an attitude of having the motor shaft extending on the plane orthogonal to the up-down direction, an upper end position of the electric motor as a heavy object can be suppressed to be low as compared with a case where the electric motor is disposed in an attitude of having the motor shaft extending in the up-down direction. As a result, the center of gravity of the watercraft is suppressed to be low, so that the stability of the watercraft during sliding can be improved.

[0105] In a watercraft according to a second aspect, in the first aspect, the electric motor has the motor shaft extending in the ship width direction.

[0106] According to the second aspect, the electric motor can be disposed along the tunnel, and an amount of protrusion of the electric motor with respect to the tunnel in a radial direction around a tunnel axis can be reduced.

[0107] In a watercraft according to a third aspect, in the first or second aspect, the electric motor is disposed at a position intersecting a width center plane that divides the ship body into two equal parts in the ship width direction.

[0108] According to the third aspect, since the electric motor is disposed near the width center plane of the ship body, a weight balance between the left and the right of the watercraft can be improved.

[0109] In a watercraft according to a fourth aspect, in the first to third aspects, the electric motor and the propeller are disposed at positions intersecting a common perpendicular plane orthogonal to the ship width direction.

[0110] According to the fourth aspect, since the electric motor and the propeller are disposed at the same position in the ship width direction, a dimension of the auxiliary propulsion device in the ship width direction can be reduced.

[0111] In a watercraft according to a fifth aspect, in the fourth aspect, the electric motor is disposed above or below the propeller.

[0112] According to the fifth aspect, a dimension of the auxiliary propulsion device in the front-rear direction can be reduced.

[0113] In a watercraft according to a sixth aspect, in the second aspect, the auxiliary propulsion device further includes a power transmission mechanism that transmits rotation of the motor shaft to the propeller, and the electric motor and the propeller are disposed on one side of the power transmission mechanism in the ship width direction.

[0114] According to the sixth aspect, since the electric motor and the propeller are disposed on the same side in the ship width direction with respect to the power transmission mechanism, a dimension of the auxiliary propulsion device in the ship width direction can be reduced.

[0115] In a watercraft according to a seventh aspect, in the sixth aspect, the power transmission mechanism functions as a speed booster that accelerates rotation of the motor shaft and transmits the rotation to the propeller.

[0116] According to the seventh aspect, the propeller can be rotated at a rotation speed at which a propulsive force that can move the watercraft is generated even in a case where the electric motor is relatively small or low output.

[0117] In a watercraft according to an eighth aspect, in the first to seventh aspects, the electric motor is disposed in an attitude of having a longitudinal direction parallel to a rotation axis of the propeller.

[0118] According to the eighth aspect, a dimension of the auxiliary propulsion device in the direction orthogonal to the rotation axis of the propeller can be reduced.

[0119] In a watercraft according to a ninth aspect, in the first to eighth aspects, the electric motor is directly or indirectly supported by a tubular tunnel wall forming the tunnel.

[0120] According to the ninth aspect, a structure of the auxiliary propulsion device can be simplified by supporting the electric motor by using the tunnel wall.

[0121] In a watercraft according to a tenth aspect, in the first to ninth aspects, the watercraft further includes a storage capable of storing luggage and provided above the electric motor.

[0122] According to the tenth aspect, since the storage is disposed above the electric motor whose upper end position is suppressed to be low, it is easy to secure a capacity of the storage.

[0123] In a watercraft according to an eleventh aspect, in the first to tenth aspects, the ship body has a motor housing part that houses the electric motor, the motor housing part having an opening that enables external access to the electric motor.

[0124] According to the eleventh aspect, the electric motor is easily accessible during maintenance of the auxiliary propulsion device.

[0125] A watercraft according to a twelfth aspect of the present disclosure includes: a ship body; a main propulsion device that includes a main prime mover and applies at least a forward propulsive force to the ship body on the basis of power of the main prime mover; and an auxiliary propulsion device that includes an auxiliary prime mover and applies, to the ship body, a propulsive force in a direction different from the propulsive force applied by the main propulsion device on the basis of power of the auxiliary prime mover. The auxiliary prime mover is disposed in an attitude of having a longitudinal direction extending on a plane orthogonal to an up-down direction of the ship body.

[0126] According to the twelfth aspect, an upper end position of the auxiliary prime mover, which is a heavy object, can be suppressed to be low, and the center of gravity of the watercraft can be suppressed to be low. As a result, stability during sliding of the watercraft can be improved.

Examples

Embodiment Construction

Overall Configuration of Personal Watercraft

[0020]FIG. 1 is a partially broken side view of a watercraft 1 according to an embodiment of the present disclosure, FIG. 2 is a plan view of the watercraft 1 as viewed from above, and FIG. 3 is a schematic front view of the watercraft 1 as viewed from the front. In the present embodiment, the watercraft 1 is a jet propulsion and riding type personal watercraft that jets a water flow to move over the water in reaction thereto. The watercraft 1 includes a ship body 10, a main propulsion device 2, and an auxiliary propulsion device 3. Hereinafter, the watercraft 1 will be appropriately abbreviated as a PWC1.

[0021]Here, front, rear, left, right, up, and down directions displayed in each figure are based on a driver M (FIG. 1) riding in the PWC1. In addition, a front-rear direction, a left-right direction, and an up-down direction of the PWC1 or the ship body 10 are defined on the basis of these respective directions. Namely, the front-rear di...

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to Japanese Patent Application No. 2025-027945, filed on Feb. 25, 2025, the entire disclosure of which is incorporated herein by reference.FIELD OF INVENTION

[0002] The present disclosure relates to a watercraft.BACKGROUND ART

[0003] As a watercraft propelled by a jet water flow, a watercraft described in US 2013 / 0102206 A is known.

[0004] Such a watercraft as described above is demanded to have high stability during sliding.SUMMARY OF THE INVENTION

[0005] An object of the present disclosure is to provide a watercraft having high stability during sliding.

[0006] In order to solve the above problem, a watercraft according to one aspect of the present disclosure includes: a ship body; a main propulsion device including a jet pump that jets a jet water flow from the ship body; and an auxiliary propulsion device including a propeller disposed in a tunnel penetrating the ship body in a ship width direction that is a width direction of the ship body, and an electric motor that rotationally drives the propeller, the electric motor having a motor shaft extending on a plane orthogonal to an up-down direction of the ship body.

[0007] A watercraft according to another aspect of the present disclosure includes: a ship body; a main propulsion device that includes a main prime mover and applies at least a forward propulsive force to the ship body on the basis of power of the main prime mover; and an auxiliary propulsion device that includes an auxiliary prime mover and applies, to the ship body, a propulsive force in a direction different from the propulsive force applied by the main propulsion device on the basis of power of the auxiliary prime mover, the auxiliary prime mover being disposed in an attitude of having a longitudinal direction extending on a plane orthogonal to an up-down direction of the ship body.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a partially broken side view of a personal watercraft according to an embodiment of the present disclosure;

[0009] FIG. 2 is a plan view of the personal watercraft as viewed from above;

[0010] FIG. 3 is a schematic front view of the personal watercraft as viewed from the front;

[0011] FIG. 4 is a side cross-sectional view illustrating a front part of the personal watercraft in a partially broken state;

[0012] FIG. 5 is a view schematically illustrating an operation mode of the personal watercraft;

[0013] FIG. 6 is a perspective view of an auxiliary propulsion device;

[0014] FIG. 7 is a front view of the auxiliary propulsion device as viewed from the front;

[0015] FIG. 8 is a cross-sectional view, corresponding to FIG. 7, of the auxiliary propulsion device;

[0016] FIG. 9 is a side view of the auxiliary propulsion device as viewed from the right;

[0017] FIG. 10 is a side view of the auxiliary propulsion device as viewed from the left;

[0018] FIG. 11 is a view equivalent to FIG. 8, illustrating a first modification of the present disclosure; and

[0019] FIG. 12 is a view equivalent to FIG. 7, illustrating a second modification of the present disclosure.DETAILED DESCRIPTIONOverall Configuration of Personal Watercraft

[0020] FIG. 1 is a partially broken side view of a watercraft 1 according to an embodiment of the present disclosure, FIG. 2 is a plan view of the watercraft 1 as viewed from above, and FIG. 3 is a schematic front view of the watercraft 1 as viewed from the front. In the present embodiment, the watercraft 1 is a jet propulsion and riding type personal watercraft that jets a water flow to move over the water in reaction thereto. The watercraft 1 includes a ship body 10, a main propulsion device 2, and an auxiliary propulsion device 3. Hereinafter, the watercraft 1 will be appropriately abbreviated as a PWC1.

[0021] Here, front, rear, left, right, up, and down directions displayed in each figure are based on a driver M (FIG. 1) riding in the PWC1. In addition, a front-rear direction, a left-right direction, and an up-down direction of the PWC1 or the ship body 10 are defined on the basis of these respective directions. Namely, the front-rear direction is a direction along a longitudinal direction of the ship body 10, where a bow side is the front and a stern side is the rear. In a state where the PWC1 is in a stationary state and no passengers and luggage are placed on the PWC1, the front-rear direction can be defined as a direction extending parallel to the longitudinal direction of the ship body 10 along a horizontal plane. The left-right direction is a direction orthogonal to the front-rear direction and parallel to a ship width direction which is a width direction of the ship body 10, and a left hand side of the driver M is the left and a right hand side is the right. The up-down direction is a direction orthogonal to the front-rear direction and the left-right direction (ship width direction), and a side facing the top is an upper side and a side opposite thereto (a side facing underwater) is a lower side. In a state where the PWC1 is in the stationary state and no passengers and luggage are placed on the PWC1, the up-down direction can be defined as a direction parallel to a vertical line.

[0022] The ship body 10 includes a hull 11 constituting a lower part of the ship body 10, and a deck 12 disposed on an upper side of the hull 11. An upper surface of the hull 11 is opened. The deck 12 covers an upper surface opening of the hull 11 and is joined to an opening edge of the hull 11 over the entire circumference. Namely, a gunnel 10G which is a joining line between the hull 11 and the deck 12 is formed on a peripheral edge of the ship body 10.

[0023] A steering handle 13 and a seat 14 are disposed on the deck 12. The steering handle 13 is attached to a front part of the deck 12. The steering handle 13 includes, for example, a handlebar that is turnable around an axis extending in a substantially up-down direction and extends in the ship width direction (left-right direction), and a throttle lever for speed adjustment attached to one end part of the handlebar. The seat 14 is disposed behind the steering handle 13 so as to cover a region including a central part of the deck 12. The seat 14 may be a seat on which at least the driver M can sit. Namely, the seat 14 may be a seat for plural persons on which not only the driver M but also fellow passengers can sit, or may be a seat for one person on which only the driver M can sit.

[0024] FIG. 4 is a side cross-sectional view illustrating a front part of the PWC1 in a partially broken state. As illustrated in this figure, a luggage room 6 is built in a front part of the ship body 10. The luggage room 6 functions as a storage for storing luggage and the like of crew members including the driver M, and is defined by a box-shaped luggage room wall 61. The luggage room 6 or the luggage room wall 61 is disposed in a space between the hull 11 and the deck 12 at the front part of the ship body 10 so as to occupy most of the space. The luggage room 6 corresponds to a “storage” in the present disclosure.

[0025] A power room ER is formed behind the luggage room 6. The power room ER is defined between the hull 11 and the deck 12, and is formed to extend in the front-rear direction from the front part to a central part of the ship body 10. A fuel tank 23 is disposed at a front part of the power room ER and immediately behind the luggage room 6. The fuel tank 23 is a tank that accumulates fuel to be supplied to a power source (an engine 21 to be described later) of the main propulsion device 2.

[0026] A front hatch 16 is attached to a front part of the deck 12. The front hatch 16 is a lid that openably covers the luggage room 6. Namely, a luggage room opening A1 for loading and unloading luggage is formed on an upper surface of the luggage room wall 61, and the front hatch 16 is attached to the front part of the deck 12 so as to cover the luggage room opening A1 from above. A front end part of the front hatch 16 is pivotally supported by the deck 12 via a hinge 16H, whereby the front hatch 16 is attached so as to be turnable in the up-down direction around the hinge 16H as indicated by an arrow Y1 in FIG. 4. Namely, the front hatch 16 is attached to the deck 12 so as to be changeable between a closed state indicated by a solid line and an open state indicated by a dashed line in FIG. 4.

[0027] As illustrated in FIGS. 1 and 2, the main propulsion device 2 includes the engine 21 as a power source and a jet pump 4 that generates a jet water flow. As also illustrated in FIG. 4, the engine 21 is housed behind the fuel tank 23 in the power room ER. The engine 21 is disposed near the center of the ship body 10 in the front-rear direction. The jet pump 4 is disposed in a rear part of the ship body 10.

[0028] The engine 21 is an internal combustion engine. The engine 21 generates power for driving the jet pump 4. The engine 21 is, for example, a water-cooled 4-stroke multi-cylinder engine driven using gasoline as fuel. The engine 21 includes a crankshaft 22 extending in the front-rear direction as an output shaft. The engine 21 corresponds to a “main prime mover” in the present disclosure.

[0029] The jet pump 4 is disposed behind the engine 21 and includes an impeller shaft 41 and an impeller 42. The impeller shaft 41 extends in the front-rear direction behind the crankshaft 22 and is coaxially connected to the crankshaft 22. When the crankshaft 22 rotates around the axis by driving of the engine 21, a rotational driving force is applied to the impeller shaft 41. The impeller 42 is attached to a rear end of the impeller shaft 41. The impeller 42 rotates around the axis to generate a jet water flow.

[0030] The ship body 10 includes an impeller passage 47 in which the jet pump 4 is disposed. The impeller passage 47 includes a water inlet 48 for taking in water (e.g., sea water) in a water landing zone of the PWC1. The water inlet 48 is formed at the center of a rear part bottom surface of the hull 11 in the ship width direction. The impeller passage 47 is formed so as to penetrate the rear part of the hull 11 in the front-rear direction. In order to apply a propulsive force to the PWC1, the jet pump 4 pressurizes and accelerates the water taken into the impeller passage 47 and jets the water rearwards.

[0031] The jet pump 4 further includes a venturi nozzle 43, a jet nozzle 44, and a reverse bucket 46. The venturi nozzle 43 and the jet nozzle 44 accelerate the water sent from the impeller 42 to generate a jet water flow. The venturi nozzle 43 is disposed behind the impeller passage 47 and has a flow path cross-sectional area that gradually decreases rearwards to increase a flow velocity. The jet nozzle 44 has an jet port 45 that opens backwards as an outlet for a jet water flow. The jet nozzle 44 is connected to a rear end part of the venturi nozzle 43 so as to be swingable left and right around an axis extending in the up-down direction. The jet nozzle 44 is driven to swing by a nozzle motor 44M. When the jet nozzle 44 swings, a jet direction of the jet water flow from the jet port 45 is changed to the left and right. The nozzle motor 44M is driven, for example, according to the steering of the steering handle 13.

[0032] The jet nozzle 44 may be attached so as to be swingable up and down around an axis extending in the ship width direction (left-right direction). Such an up-down direction swinging function of the jet nozzle 44 enables adjustment of a sliding attitude of the PWC1. For example, the more the jet nozzle 44 is inclined downward by swinging, the more a height of the bow of the PWC1 in a sliding state can be increased.

[0033] The reverse bucket 46 has a function of switching a propulsion direction of the PWC1 forwards or rearwards. The reverse bucket 46 is disposed in the vicinity of the jet port 45, and is attached to the jet nozzle 44 so as to be turnable around an axis extending in the left-right direction. When the reverse bucket 46 descends so as to cover the jet port 45, the jet water flow is redirected forwards, and the propulsion direction of the PWC1 is changed rearwards.

[0034] The auxiliary propulsion device 3 generates a water flow in the ship width direction (left-right direction), i.e., a water flow directed leftwards or rightwards from the front part of the ship body 10. This water flow imparts a propulsive force in the ship width direction to the ship body 10. Although the present embodiment shows an example in which a water flow is jetted straight in the ship width direction from the auxiliary propulsion device 3, the water flow may be a water flow in a direction inclined with respect to the ship width direction.

[0035] The ship body 10 includes a tunnel 5 at a position corresponding to the auxiliary propulsion device 3. The tunnel 5 is a passage extending so as to linearly penetrate the hull 11 in the ship width direction at the front part of the ship body 10. The tunnel 5 is defined by a tunnel wall 50 (FIG. 4) which is a cylindrical wall extending in the ship width direction. The tunnel 5 has an opening at each of opposite ends of the tunnel 5. As illustrated in FIGS. 2 and 3, a first tunnel opening 5A is opened at one end of the tunnel 5, and a second tunnel opening 5B is opened at the other end. The first tunnel opening 5A opens on a left side surface of a front part of the hull 11. The second tunnel opening 5B opens on a right side surface of the front part of the hull 11. The first tunnel opening 5A and the second tunnel opening 5B are formed ahead of the engine 21 and the jet pump 4.

[0036] The tunnel 5 is disposed ahead of the steering handle 13 and the fuel tank 23. Namely, the tunnel 5 is disposed between the steering handle 13 (or the fuel tank 23) and the bow in the front-rear direction.

[0037] In addition, the first tunnel opening 5A and the second tunnel opening 5B of the tunnel 5 are located below a water surface at least when the PWC1 is stationary or in a non-sliding state of moving at a slow speed. In other words, the tunnel openings 5A and 5B are located at a height close to a ship bottom. For example, upper ends of the tunnel openings 5A and 5B are located below upper ends of the engine 21 and the fuel tank 23. As a result, since a height of the tunnel 5 becomes relatively low, components such as an electric motor 51 to be described later can be easily disposed above the tunnel 5.

[0038] On the other hand, when the PWC1 is in the sliding state, the tunnel openings 5A and 5B can be located above the water surface. When the tunnel openings 5A and 5B are located above the water surface, the tunnel openings 5A and 5B are prevented from becoming resistive elements at the time of sliding.

[0039] The auxiliary propulsion device 3 discharges fluid from the inside of the tunnel 5 to the outside of the ship body 10 through the first tunnel opening 5A or the second tunnel opening 5B, and by a reaction force thereof, generates the propulsive force in the ship width direction. Although the discharged fluid is basically water (e.g., sea water) in the water landing zone of the PWC1, the fluid may contain air. In the present specification, a flow of the fluid discharged from the tunnel 5 in this manner is simply referred to as a water flow.

[0040] As illustrated mainly in FIG. 3, the auxiliary propulsion device 3 includes the electric motor 51, a propeller 52, and a gear mechanism 53. The electric motor 51 is a power source for obtaining the propulsive force in the ship width direction, and rotationally drives the propeller 52. The electric motor 51 may be an AC motor or a DC motor. The propeller 52 is disposed in the tunnel 5 and rotates in the tunnel 5. The gear mechanism 53 transmits a driving force of the electric motor 51 to the propeller 52. Namely, when the electric motor 51 is driven, power of the electric motor 51 is transmitted to the propeller 52 via the gear mechanism 53, so that the propeller 52 rotates. Rotation of the propeller 52 generates a water flow in the tunnel 5, and discharge of the water flow generates the propulsive force in the ship width direction. The electric motor 51 corresponds to an “auxiliary prime mover” in the present disclosure, and the gear mechanism 53 corresponds to a “power transmission mechanism” in the present disclosure.

[0041] FIG. 5 is a view schematically illustrating an operation mode of the PWC1. In FIG. 5, two operation modes of sliding and turning are illustrated. In the sliding mode, the main propulsion device 2 is activated and jets a jet water flow backwards from the jet pump 4, as indicated by an arrow F1. The PWC1 moves forwards as indicated by an arrow D1 upon receiving a forward propulsive force applied to the rear part of the ship body 10 due to a reaction of the jet water flow. When the reverse bucket 46 is activated to cover the jet port 45, the PWC1 is propelled backwards.

[0042] In addition, in the sliding mode, it is possible to revolve the PWC1 by the steering of the steering handle 13. Namely, a direction of the jet water flow is changed to either the left or right by leftward or rightward swinging of the jet nozzle 44 accompanying the steering of the steering handle 13, and the PWC1 revolves accordingly. For example, in a case where the jet nozzle 44 is swung rightwards by the steering handle 13, a jet water flow is jetted diagonally rearwards to the right as indicated by an arrow F1A. As indicated by an arrow D1A, the PWC1 revolves rightwards upon receiving a left diagonal forward propulsive force applied to the rear part of the ship body 10 due to the reaction of the jet water flow. Conversely, when the jet nozzle 44 is swung leftwards, the PWC1 revolves leftwards. During such revolution, while straddling the seat 14, the driver M may perform manipulation of inclining the ship body 10 around an axis extending in the front-rear direction, i.e., manipulation of banking the ship body 10 to either the left or the right by his / her weight movement in order to resist a centrifugal force accompanying the revolution.

[0043] In the turning mode, the main propulsion device 2 is deactivated and the auxiliary propulsion device 3 is activated, thereby causing the PWC1 to stationarily turn. For example, as indicated by an arrow F2 in FIG. 5, when the auxiliary propulsion device 3 is activated so that a water flow is discharged leftwards from the first tunnel opening 5A, a reaction of the water flow causes application of a rightward propulsive force to the front part of the ship body 10. Upon receiving this propulsive force, as indicated by an arrow D2, the PWC1 turns clockwise around a center of gravity G thereof. Conversely, when the auxiliary propulsion device 3 is activated so that the water flow is discharged rightwards from the second tunnel opening 5B, a leftward propulsive force is applied to the front part of the ship body 10, so that the PWC1 turns counterclockwise.

[0044] Although not illustrated in FIG. 5, an operation mode in which both the main propulsion device 2 and the auxiliary propulsion device 3 are activated may be set separately from the sliding mode and the turning mode.Details of Auxiliary Propulsion Device

[0045] Details of the auxiliary propulsion device 3 will be further described. FIG. 6 is a perspective view of the auxiliary propulsion device 3, FIG. 7 is a front view of the auxiliary propulsion device 3 as viewed from the front, FIG. 8 is a cross-sectional view corresponding to the auxiliary propulsion device 3 in FIG. 7, FIG. 9 is a side view of the auxiliary propulsion device 3 as viewed from the right, and FIG. 10 is a side view of the auxiliary propulsion device 3 as viewed from the left. As illustrated in each drawing, the electric motor 51 is disposed outside the tunnel 5 near the center in a ship width direction (left-right direction) of the tunnel 5. In the present embodiment, the electric motor 51 is disposed above the tunnel 5, and is opposed to an upper surface of the tunnel wall 50 with a slight distance.

[0046] The electric motor 51 includes a tubular motor case 511, an electric unit 512 including electromagnetic components such as a rotor and a stator housed inside the motor case 511, and a motor shaft 513 extending from the electric unit 512 to the outside of the motor case 511.

[0047] The motor shaft 513 extends in the ship width direction. Namely, the electric motor 51 is disposed in an attitude in which the motor shaft 513 extends in the ship width direction, in other words, in an attitude in which the motor shaft 513 extends on a plane orthogonal to the up-down direction. An extending direction of the motor shaft 513 is parallel to a tunnel axis which is a central axis of the tunnel 5. The motor shaft 513 has one end part fixed to the above rotor of the electric unit 512. In the present embodiment, a right end part of the motor shaft 513 extending in the ship width direction (left-right direction) is fixed to the rotor, and the motor shaft 513 extends leftwards from the electric unit 512 toward the outside of the motor case 511. A part of the motor shaft 513 extending to the outside of the motor case 511 is inserted inside an upper part (a first case part 531a to be described later) of the gear mechanism 53. When the electric motor 51 is driven, the above rotor rotates with respect to the above stator by energization, and the motor shaft 513 rotates integrally with the rotor.

[0048] The electric motor 51 has a shape elongated in a longitudinal direction such that the ship width direction (left-right direction), which is the extending direction of the motor shaft 513, becomes the longitudinal direction. Namely, the electric motor 51 is disposed such that its longitudinal direction extends on a plane orthogonal to the up-down direction.

[0049] The propeller 52 includes an impeller 521 rotatable in the tunnel 5, and a propeller shaft 522 (rotation shaft) coaxially coupled to the impeller 521.

[0050] The propeller shaft 522 extends in the ship width direction in the tunnel 5. Namely, the propeller 52 is disposed in an attitude in which the propeller shaft 522 extends in the ship width direction, in other words, in an attitude in which the propeller shaft 522 extends on the plane orthogonal to the up-down direction. The propeller shaft 522 is disposed at the center of the tunnel 5, i.e., at the center of a circular cross section of the tunnel 5.

[0051] The impeller 521 has a boss 521a fixed to one end part of the propeller shaft 522, and a plurality of vanes 521b extending radially outward from a peripheral surface of the boss 521a. In the present embodiment, the propeller shaft 522 is disposed so as to protrude rightwards from the inside of a lower part (a second case part 531b to be described later) of the gear mechanism 53 disposed in the tunnel 5, and the boss 521a of the impeller 521 is fixed to a right end part of the propeller shaft 522. The propeller shaft 522 rotates upon reception of a rotational force transmitted from the electric motor 51 via the gear mechanism 53. The impeller 521 rotates integrally with the propeller shaft 522 to generate a water flow.

[0052] Here, as described above, in the present embodiment, both the motor shaft 513 and the propeller shaft 522 extend in the ship width direction. Namely, the electric motor 51 and the propeller 52 are disposed such that the motor shaft 513 and the propeller shaft 522 are parallel to each other. Alternatively, the electric motor 51 is disposed in an attitude of having its longitudinal direction parallel to the propeller shaft 522.

[0053] As mainly illustrated in FIG. 8, the gear mechanism 53 has a gear case 531, and a first gear 532 and a second gear 533 housed in the gear case 531.

[0054] The first gear 532 is externally fitted to the motor shaft 513 so as to rotate integrally with the motor shaft 513. The second gear 533 is externally fitted to the propeller shaft 522 so as to rotate integrally with the propeller shaft 522. Each of the first gear 532 and the second gear 533 is a spur gear in which a large number of linear teeth are formed on an outer peripheral surface. Both the gears 532 and 533 are meshed so as to rotate in conjunction with each other.

[0055] Although the gear mechanism 53 may function as either a speed reducer or a speed booster, in the present embodiment, the gear mechanism 53 functions as a speed booster. Namely, an outer diameter of the first gear 532 is larger than an outer diameter of the second gear 533. When rotation of the first gear 532 is transmitted to the second gear 533, the second gear 533 rotates at a speed higher than that of the first gear 532. Namely, the gear mechanism 53 in the present embodiment accelerates the rotation of the motor shaft 513 and transmits the rotation to the propeller shaft 522.

[0056] The gear case 531 has a first case part 531a that houses the first gear 532 and a second case part 531b that houses the second gear 533. The second case part 531b is disposed in the tunnel 5. The second case part 531b has a substantially circular shape as viewed in the ship width direction, and has an outer diameter smaller than a diameter of the tunnel 5. The first case part 531a has a circular shape having an outer diameter larger than that of the second case part 531b as viewed in the ship width direction, and is continuous with an upper part of the second case part 531b. The first case part 531a has a most part of an upper side thereof located outside the tunnel 5, and a part of a lower side thereof entering the inside of the tunnel 5 to be continuous with the second case part 531b.

[0057] A bearing 535 that rotatably supports the motor shaft 513 is disposed inside the first case part 531a. A bearing 536 that rotatably supports the propeller shaft 522 is disposed inside the second case part 531b.

[0058] The gear case 531 has a first fixing part 531c functioning as a fixing part to the electric motor 51 and a second fixing part 531d functioning as a fixing part to the tunnel wall 50. The first fixing part 531c is formed in a tubular shape protruding rightwards from the first case part 531a toward the electric motor 51. The first fixing part 531c and the motor case 511 are coupled to each other with a bolt or the like via a flange 55. The second fixing part 531d is formed in a rectangular frame shape as viewed in the up-down direction so as to surround a lower part of the first case part 531a. The second fixing part 531d is fixed to a pedestal 50a formed at a central part of the tunnel wall 50 in the ship width direction in a state of being placed on an upper surface of the pedestal 50a. The pedestal 50a has a shape similar to an arch-shaped gate, and is formed so as to protrude radially outward from an upper half part of the central part of the tunnel wall 50. On the upper surface of the pedestal 50a, an opening is formed which has a rectangular shape as viewed in the up-down direction corresponding to an opening on a lower surface of the second fixing part 531d. The second fixing part 531d is joined to the pedestal 50a from above by an appropriate means such as welding. As a result, the gear case 531 is fixed to the tunnel wall 50 in a state of having a part of a lower side thereof including the second case part 531b entering the tunnel 5.

[0059] As described above, in the present embodiment, the gear case 531 is fixed to the tunnel wall 50, and the motor case 511 is fixed to the gear case 531. Namely, the electric motor 51 is indirectly supported by the tunnel wall 50 via the gear case 531.

[0060] The electric motor 51 and the propeller 52 are disposed on one side of the gear mechanism 53 in the ship width direction (left-right direction). Although the electric motor 51 and the propeller 52 can be disposed on either a left side or a right side of the gear mechanism 53, in the present embodiment, both are disposed on the right side of the gear mechanism 53. For example, the electric motor 51 is disposed on the right side of the gear mechanism 53 by fixing the motor case 511 to an upper part (first case part 531a) of the gear case 531 from the right side. In addition, the propeller 52 is disposed on the right side of the gear mechanism 53 by being supported in a state where the propeller shaft 522 is inserted from the right side into a lower part (the second case part 531b) of the gear case 531.

[0061] When the auxiliary propulsion device 3 is in use, for example, when the auxiliary propulsion device 3 is activated for executing the turning mode shown in FIG. 5, the propeller 52 is rotated by driving of the electric motor 51, so that a water flow is generated in the tunnel 5. Namely, when the motor shaft 513 is rotated by driving of the electric motor 51, the first gear 532 fixed to the motor shaft 513 rotates, and the second gear 533 meshed with the first gear 532 rotates. As a result, the propeller shaft 522 fixed to the second gear 533 rotates, and the impeller 521 fixed to the propeller shaft 522 rotates. The rotation of the impeller 521 generates a water flow in the tunnel 5, and the water flow is discharged from the tunnel 5 toward one of the left and right directions.

[0062] Here, a direction of the water flow discharged from the tunnel 5 is decided by a rotation direction of the motor shaft 513 of the electric motor 51. For example, when the electric motor 51 is driven so that the motor shaft 513 rotates in a predetermined forward rotation direction, the propeller 52 rotates so as to generate a water flow from left to right in the tunnel 5. Namely, as indicated by an open arrow in FIG. 6, the fluid is taken in from the first tunnel opening 5A, and is discharged rightwards from the second tunnel opening 5B. A reaction force caused by the discharge serves as a propulsive force for moving the PWC1 leftwards. On the other hand, when the electric motor 51 is driven so that the motor shaft 513 rotates in a reverse rotation direction opposite to the forward rotation direction, the propeller 52 rotates so that a water flow directed from right to left is generated in the tunnel 5. Namely, conversely to the open arrow in FIG. 6, the fluid is taken in from the second tunnel opening 5B, and is discharged leftwards from the first tunnel opening 5A. A reaction force caused by the discharge serves as a propulsive force for moving the PWC1 rightwards.

[0063] A plane CP illustrated in FIGS. 3, 7, and 8 is a width center plane that divides the ship body 10 into two equal parts in the ship width direction. The width center plane CP is a plane extending in the up-down direction through the center of gravity G of the PWC1, and is orthogonal to the ship width direction. Namely, the width center plane CP coincides with a vertical line passing through the center of gravity G when viewed from the front in a normal state where the ship body 10 is inclined neither to the left nor to the right. The above-described electric motor 51 and propeller 52 in the auxiliary propulsion device 3 are disposed at positions intersecting the width center plane CP.

[0064] Specifically, the electric motor 51 is disposed near the center of the ship body 10 in the ship width direction such that the width center plane CP intersects any part of the electric motor 51. Here, an axis X1 illustrated in FIG. 8 is a motor central axis which is a center of the motor shaft 513, and a direction along the motor central axis X1 is assumed to be an axial direction of the electric motor 51. Here, the axial direction of the electric motor 51 is synonymous with a longitudinal direction of the electric motor 51. In the present embodiment, the electric motor 51 is disposed such that the width center plane CP intersects an axial intermediate position of the electric motor 51. Namely, the width center plane CP is located between a right end of the motor case 511, which is one axial end of the electric motor 51, and a left end of the motor shaft 513, which is the other axial end of the electric motor 51. More specifically, the width center plane CP is located between one end and the other end in an axial direction of the motor case 511. In other words, the electric motor 51 is disposed so as to intersect the width center plane CP at an intermediate position in the axial direction of the motor case 511. More preferably, the electric motor 51 is disposed at a position such that the width center plane CP passes through the center of gravity of the electric motor 51.

[0065] Similarly, the propeller 52 is disposed near the center of the ship body 10 in the ship width direction such that the width center plane CP intersects any part of the propeller 52. Here, an axis X2 illustrated in FIG. 8 is a propeller central axis which is a center of the propeller shaft 522, and a direction along the propeller central axis X2 is assumed to be an axial direction of the propeller 52. In the present embodiment, the propeller 52 is disposed such that the width center plane CP intersects an axial intermediate position of the propeller 52. Namely, the width center plane CP is located between a right end of the impeller 521, which is one end in the axial direction of the propeller52, and a left end of the propeller shaft 522, which is the other end in the axial direction of the propeller 52. More specifically, the width center plane CP is located at a position corresponding to the vane 521b of the impeller 521. In other words, the propeller 52 is disposed so as to intersect the width center plane CP at a position of the vane 521b.

[0066] Here, as described above, the electric motor 51 and the propeller 52 are located at positions intersecting the common width center plane CP. The electric motor 51 is disposed above the tunnel 5, and the propeller 52 is disposed inside the tunnel 5. Namely, the electric motor 51 and the propeller 52 are disposed to have a relationship in which the electric motor 51 is located above the propeller 52 across the tunnel wall 50 near a width center of the ship body 10.

[0067] As illustrated in FIG. 4, the electric motor 51 is disposed between a rear surface of the luggage room wall 61 (luggage room 6) and a front surface of the fuel tank 23 in a side view. In other words, the ship body 10 has, between the luggage room wall 61 and the fuel tank 23, a motor housing part S1 for housing the electric motor 51.

[0068] The luggage room wall 61 has a shielding part 61a that covers the electric motor 51 from above. The shielding part 61a is formed with an access opening A2 for enabling access to the electric motor 51 at the time of maintenance of the auxiliary propulsion device 3. A lid member 62 for closing the access opening A2 is detachably attached to the luggage room wall 61. Namely, at the time of maintenance of the auxiliary propulsion device 3, an operator opens the front hatch 16 and removes the lid member 62. As a result, the electric motor 51 can be accessed from the outside through the luggage room opening A1 and the access opening A2. Namely, in the present embodiment, in order to secure accessibility to the electric motor 51 even in a case where the luggage room 6 exists above the electric motor 51, the electric motor 51 is housed in the motor housing part S1 with the access opening A2.

[0069] Although not illustrated in the drawings, a battery that accumulates electric power supplied to the electric motor 51 can be disposed in the vicinity of the electric motor 51. For example, the batteries may be disposed side by side with the electric motor 51 in an axial direction of the tunnel 5, i.e., in the ship width direction. Alternatively, the battery may be disposed at a position lower than an upper end of the electric motor 51 and behind the tunnel 5.Operation and Effects

[0070] As described in the foregoing, in the present embodiment, the electric motor 51, which is the power source of the auxiliary propulsion device 3, is disposed in the attitude in which the motor shaft 513 extends in the ship width direction. Therefore, as compared with a case where the motor shaft 513 extends in the up-down direction, stability at the time of sliding of the PWC1 can be improved.

[0071] Namely, in the present embodiment, since the electric motor 51 is disposed in the attitude in which the motor shaft 513 extends in the ship width direction, i.e., in the attitude in which the motor shaft 513 extends on a plane orthogonal to the up-down direction, an upper end position of the electric motor 51, which is a heavy object, can be suppressed to be low as compared with a case where the electric motor 51 is disposed in the attitude in which the motor shaft 513 extends in the up-down direction. As a result, the center of gravity G of the PWC1 can be kept low, so that the stability of the PWC1 during sliding can be improved. Furthermore, since the stability is improved, operability of the PWC1 can be improved.

[0072] Here, in the PWC1, a width dimension, which is a dimension in the left-right direction of the ship body 10, is significantly smaller than a length dimension, which is a dimension in the front-rear direction of the ship body 10. Namely, in the PWC1, a ratio of the width dimension to the length dimension of the ship body 10 is often smaller than that of a common ship. Therefore, the PWC1 tends to roll side-to-side due to an influence of waves and wind on the water. By contrast, according to the present embodiment in which the center of gravity G of the PWC1 is suppressed to be low, it is possible to reduce ease of side-to-side rolling of the PWC1, and it is also possible to improve the stability of the PWC1 in that sense.

[0073] In addition, although in the PWC1, the driver M may perform manipulation to bank the ship body 10 to either the left or the right by moving his / her weight during the revolution, such banking manipulation may not be easy particularly for a beginner. By contrast, according to the present embodiment in which the center of gravity G of the PWC1 is suppressed to be low, since an excessive attitude change of the PWC1 due to the banking manipulation is suppressed, the banking manipulation can be facilitated, and the operability of the PWC1 can be improved in that sense as well.

[0074] Furthermore, at the time of forward movement using the main propulsion device 2, as a moving speed increases, the PWC1 makes a state transition to the sliding state in which the ship moves sliding on the water surface with the bow lifting up from the water. In this case, according to the present embodiment in which the center of gravity G of the PWC1 is suppressed to be low, the bow is likely to lift up from the water surface, so that the shift of the PWC1 to the sliding state can be promoted.

[0075] Moreover, since the motor shaft 513 extends in the ship width direction, the electric motor 51 can be disposed along the tunnel 5. As a result, an amount by which the electric motor 51 protrudes in a radial direction around the central axis (tunnel axis) of the tunnel 5 with respect to the tunnel 5 can be reduced. In particular, in a case where the electric motor 51 is disposed above the tunnel 5 as in the present embodiment, an amount of protrusion of the electric motor 51 in the front-rear direction with respect to the tunnel 5 can be reduced. In other words, according to the present embodiment in which the electric motor 51 is disposed such that the motor shaft 513 extends parallel to the tunnel shaft, the auxiliary propulsion device 3 including the electric motor 51 can be made compact in the radial direction (or the front-rear direction) of the tunnel 5.

[0076] Furthermore, in the present embodiment, the electric motor 51 and the propeller 52 are disposed at positions intersecting the width center plane CP which is a common perpendicular plane orthogonal to the ship width direction. In other words, the electric motor 51 and the propeller 52 are disposed in a layout in which a power transmission path from the electric motor 51 to the propeller 52 is folded back in a U shape. According to such a configuration, since the electric motor 51 and the propeller 52 are disposed at positions close to each other in the ship width direction, a dimension of the auxiliary propulsion device 3 in the ship width direction can be reduced as compared with a case where the power transmission path has a non-U shape.

[0077] Moreover, since the width center plane CP is a plane that divides the ship body 10 into two equal parts in the ship width direction, disposing the electric motor 51 at a position intersecting the width center plane CP realizes a layout in which the electric motor 51 as a heavy object is located near the width center of the ship body 10. As a result, the center of gravity G of the PWC1 can be easily brought closer to the width center of the ship body 10 to improve a weight balance between the left and the right of the PWC1.

[0078] Furthermore, since the propeller 52 is disposed at a position intersecting the width center plane CP, i.e., the propeller 52 is disposed near the center in the ship width direction in the tunnel 5, in either case where the direction of the water flow caused by the rotation of the propeller 52 is set to the left or the right, the same propulsive force can be easily exerted to improve usability of the auxiliary propulsion device 3.

[0079] In the present embodiment, both the motor shaft 513 and the propeller shaft 522 extend in the ship width direction and are disposed in parallel with each other. According to such a configuration, for example, unlike a case where the motor shaft 513 and the propeller shaft 522 are not parallel, such as a case where the motor shaft 513 is disposed to extend in the front-rear direction, a structure of the gear mechanism 53 that links the motor shaft 513 and the propeller shaft 522 can be simplified.

[0080] In addition, in the present embodiment, the electric motor 51 is disposed above the propeller 52 (tunnel 5). According to such a configuration, a dimension in the front-rear direction of the auxiliary propulsion device 3 can be reduced as compared with a case where the electric motor 51 is disposed ahead of or behind the propeller 52. In addition, as compared with a case where the electric motor 51 is disposed below the propeller 52, i.e., between the tunnel 5 and the ship bottom, the tunnel 5 can be easily brought close to the ship bottom, and the tunnel openings 5A and 5B can be easily disposed below the water surface at the time of non sliding of the PWC1.

[0081] Also in the present embodiment, the gear mechanism 53 that transmits the rotation of the motor shaft 513 to the propeller shaft 522 is provided, and the electric motor 51 and the propeller 52 are both disposed on the right side of the gear mechanism 53. Thus, in a case where the electric motor 51 and the propeller 52 are disposed on the same side in the ship width direction with respect to the gear mechanism 53, the dimension in the ship width direction of the auxiliary propulsion device 3 can be reduced as compared with the case where they are disposed on the opposite sides with the gear mechanism 53 interposed therebetween.

[0082] In addition, in the present embodiment, the gear mechanism 53 functions as a speed booster that accelerates the rotation of the motor shaft 513 and transmits the rotation to the propeller shaft 522. According to such a configuration, even in a case where the electric motor 51 is relatively small or low output, by transmitting the rotation of the electric motor 51 to the propeller 52 via the gear mechanism 53 (speed booster), the propeller 52 can be rotated at a rotation speed at which a propulsive force that can move the PWC1 is generated.

[0083] In the present embodiment, the electric motor 51 is indirectly supported by the tunnel wall 50 constituting the tunnel 5 via the gear case 531. Thus, in a case where the electric motor 51 is supported using the tunnel wall 50, the structure of the auxiliary propulsion device 3 can be simplified.

[0084] In the present embodiment, the luggage room 6 is disposed above the electric motor 51. Thus, in a case where the luggage room 6 is disposed above the electric motor 51 whose upper end position is suppressed to be low, a capacity of the luggage room 6 can be sufficiently secured.

[0085] Furthermore, in the luggage room wall 61 constituting the luggage room 6, the access opening A2 that enables external access to the electric motor 51 is formed in the shielding part 61a that covers the electric motor 51 from above. According to such a configuration, the electric motor 51 can be easily accessed through the access opening A2 at the time of maintenance of the auxiliary propulsion device 3, and maintainability can be improved.Modification

[0086] Although the preferred embodiment of the present disclosure has been described in the foregoing, the present disclosure is not limited thereto, and for example, the following modifications are possible.

[0087] Although in the above embodiment, the gear mechanism 53 including the first gear 532 and the second gear 533 meshed with each other is used as the power transmission mechanism that transmits the rotation of the motor shaft 513 to the propeller shaft 522, the configuration of the power transmission mechanism is not limited thereto. For example, one or more relay gears may be provided between the first gear 532 and the second gear 533. Instead of the above embodiment in which the outer diameter of the first gear 532 is larger than the outer diameter of the second gear 533, the outer diameter of the first gear 532 may be smaller than the outer diameter of the second gear 533. Namely, the gear mechanism 53 may function as a speed reducer instead of a speed booster.

[0088] Furthermore, a power transmission mechanism using a mechanism other than gears may be used. For example, as illustrated in FIG. 11, a power transmission mechanism 73 including a chain or a belt may be used. Specifically, the power transmission mechanism 73 illustrated in FIG. 11 includes a first pulley 732 fixed to the motor shaft 513, a second pulley 733 fixed to the propeller shaft 522, an endless transmission member 734 formed of a chain or a belt wound between the first pulley 732 and the second pulley 733, and a gear case 731 housing these elements 732, 733, and 734. Even when such power transmission mechanism 73 is used, the rotation of the motor shaft 513 can be appropriately transmitted to the propeller shaft 522. Moreover, since outer diameters of the first pulley 732 and the second pulley 733 are easily reduced, an upper end position of the gear case 731 can be suppressed to be low as compared with the above embodiment, and a dimension of the up-down direction of the auxiliary propulsion device 3 can be advantageously reduced.

[0089] In the above embodiment, both the electric motor 51 and the propeller 52 are disposed at the positions intersecting the width center plane CP that divides the ship body 10 into two equal parts in the ship width direction. However, at least one of the electric motor 51 and the propeller 52 may be disposed at a position not intersecting the width center plane CP, i.e., at a position away from the width center plane CP in the ship width direction.

[0090] Although in the above embodiment, the electric motor 51 is disposed outside the luggage room 6, the electric motor 51 may be disposed inside the luggage room 6.

[0091] Although the above embodiment has been described with respect to the example in which the electric motor 51 and the propeller 52 are disposed on one side of the gear mechanism 53 in the ship width direction, the electric motor 51 and the propeller 52 may be disposed on the opposite sides in the ship width direction with the gear mechanism 53 interposed therebetween. For example, as illustrated in FIG. 12, the electric motor 51 may be disposed on the left side of the gear mechanism 53, and the propeller 52 may be disposed on the right side of the gear mechanism 53. As a matter of course, a positional relationship between the electric motor 51 and the propeller 52 can be made reverse to that in FIG. 12.

[0092] Although in the above embodiment, the electric motor 51 is indirectly supported by the tunnel wall 50 via the gear case 531, the electric motor 51 may be directly supported by the tunnel wall 50.

[0093] In the above embodiment, the axial direction or the longitudinal direction of the electric motor 51 is parallel to the ship width direction (left-right direction). However, the axial direction or the longitudinal direction of the electric motor 51 only needs to be a direction extending on a plane orthogonal to the up-down direction of the ship body 10, and is not necessarily parallel to the ship width direction. For example, the axial direction or the longitudinal direction of the electric motor 51 may be parallel to the front-rear direction or may be a direction intersecting the front-rear direction and the ship width direction. In other words, the motor shaft 513 need not be parallel to the propeller shaft 522, but may be non-parallel to the propeller shaft 522. Even in a case where the two are not parallel to each other, when a mechanism including, for example, a bevel gear is used as the gear mechanism 53, the rotation of the motor shaft 513 can be transmitted to the propeller shaft 522 through the mechanism without any trouble.

[0094] Although the above embodiment has been described with respect to the example in which the electric motor 51 is disposed above the propeller 52 and outside the tunnel 5, the electric motor may be disposed coaxially with the propeller shaft 522. Namely, in the tunnel 5, the motor shaft and the propeller shaft may be disposed on the same axis extending in the ship width direction. In addition, the propeller shaft may be directly coupled to the rotor of the electric motor. Furthermore, the propeller 52 may be rotated by a ring-shaped electric motor (hollow motor) disposed in the tunnel 5.

[0095] Although the above embodiment shows the example in which the propeller 52 is rotated by one electric motor 51, a plurality of electric motors 51 may be used. For example, a forward rotation electric motor and a reverse rotation electric motor may be prepared.

[0096] Although in the above embodiment, the electric motor 51 is disposed above the propeller 52 (tunnel 5), the electric motor 51 may be disposed below the propeller 52.

[0097] Furthermore, the electric motor 51 may be disposed ahead of or behind the propeller 52 (tunnel 5). In a case where the electric motor 51 is disposed behind the propeller 52, the position of the center of gravity G of the PWC1 relatively approaches the stern, so that a moment of inertia required to lift the bow from the water surface is reduced, resulting in promoting the PWC1 to make a transition to the sliding state.

[0098] Although the above embodiment has been described with respect to the example in which the main prime mover that is the power source of the main propulsion device 2 is the internal combustion engine 21, the type of the main prime mover is not limited thereto. For example, the main prime mover may be an electric motor.

[0099] Although the above embodiment has been described with respect to the example in which the auxiliary prime mover that is the power source of the auxiliary propulsion device 3 is the electric motor 51, the type of the auxiliary prime mover is not limited thereto. For example, the auxiliary prime mover may be an internal combustion engine, or may be a fluid motor that rotates upon receiving a supply of fluid.

[0100] The above embodiment has been described with respect to the example in which the present disclosure is applied to the personal watercraft (PWC) 1 that is a jet propulsion and riding type personal watercraft. However, a watercraft to which the present disclosure can be applied is not limited to a personal watercraft as long as the watercraft can move on water in a sliding state. For example, the present disclosure can also be applied to a watercraft that obtains a propulsive force by a method other than jet water flow jetting, e.g., by rotation of a propeller, and to a watercraft that performs steering using a steering wheel instead of a steering handle.

[0101] Although the above embodiment has been described with respect to the example in which the present disclosure is applied to the PWC1 including the luggage room 6 provided in the front part of the ship body 10, the present disclosure is naturally applicable to a watercraft in which the luggage room 6 is omitted.Conclusion

[0102] The above embodiment and modifications thereof include the following disclosure.

[0103] A watercraft according to a first aspect of the present disclosure includes: a ship body; a main propulsion device including a jet pump that jets a jet water flow from the ship body; and an auxiliary propulsion device including a propeller disposed in a tunnel penetrating the ship body in a ship width direction that is a width direction of the ship body, and an electric motor that rotationally drives the propeller. The electric motor has a motor shaft extending on a plane orthogonal to an up-down direction of the ship body.

[0104] According to the first aspect, by disposing the electric motor for the auxiliary propulsion device so as to have an attitude of having the motor shaft extending on the plane orthogonal to the up-down direction, an upper end position of the electric motor as a heavy object can be suppressed to be low as compared with a case where the electric motor is disposed in an attitude of having the motor shaft extending in the up-down direction. As a result, the center of gravity of the watercraft is suppressed to be low, so that the stability of the watercraft during sliding can be improved.

[0105] In a watercraft according to a second aspect, in the first aspect, the electric motor has the motor shaft extending in the ship width direction.

[0106] According to the second aspect, the electric motor can be disposed along the tunnel, and an amount of protrusion of the electric motor with respect to the tunnel in a radial direction around a tunnel axis can be reduced.

[0107] In a watercraft according to a third aspect, in the first or second aspect, the electric motor is disposed at a position intersecting a width center plane that divides the ship body into two equal parts in the ship width direction.

[0108] According to the third aspect, since the electric motor is disposed near the width center plane of the ship body, a weight balance between the left and the right of the watercraft can be improved.

[0109] In a watercraft according to a fourth aspect, in the first to third aspects, the electric motor and the propeller are disposed at positions intersecting a common perpendicular plane orthogonal to the ship width direction.

[0110] According to the fourth aspect, since the electric motor and the propeller are disposed at the same position in the ship width direction, a dimension of the auxiliary propulsion device in the ship width direction can be reduced.

[0111] In a watercraft according to a fifth aspect, in the fourth aspect, the electric motor is disposed above or below the propeller.

[0112] According to the fifth aspect, a dimension of the auxiliary propulsion device in the front-rear direction can be reduced.

[0113] In a watercraft according to a sixth aspect, in the second aspect, the auxiliary propulsion device further includes a power transmission mechanism that transmits rotation of the motor shaft to the propeller, and the electric motor and the propeller are disposed on one side of the power transmission mechanism in the ship width direction.

[0114] According to the sixth aspect, since the electric motor and the propeller are disposed on the same side in the ship width direction with respect to the power transmission mechanism, a dimension of the auxiliary propulsion device in the ship width direction can be reduced.

[0115] In a watercraft according to a seventh aspect, in the sixth aspect, the power transmission mechanism functions as a speed booster that accelerates rotation of the motor shaft and transmits the rotation to the propeller.

[0116] According to the seventh aspect, the propeller can be rotated at a rotation speed at which a propulsive force that can move the watercraft is generated even in a case where the electric motor is relatively small or low output.

[0117] In a watercraft according to an eighth aspect, in the first to seventh aspects, the electric motor is disposed in an attitude of having a longitudinal direction parallel to a rotation axis of the propeller.

[0118] According to the eighth aspect, a dimension of the auxiliary propulsion device in the direction orthogonal to the rotation axis of the propeller can be reduced.

[0119] In a watercraft according to a ninth aspect, in the first to eighth aspects, the electric motor is directly or indirectly supported by a tubular tunnel wall forming the tunnel.

[0120] According to the ninth aspect, a structure of the auxiliary propulsion device can be simplified by supporting the electric motor by using the tunnel wall.

[0121] In a watercraft according to a tenth aspect, in the first to ninth aspects, the watercraft further includes a storage capable of storing luggage and provided above the electric motor.

[0122] According to the tenth aspect, since the storage is disposed above the electric motor whose upper end position is suppressed to be low, it is easy to secure a capacity of the storage.

[0123] In a watercraft according to an eleventh aspect, in the first to tenth aspects, the ship body has a motor housing part that houses the electric motor, the motor housing part having an opening that enables external access to the electric motor.

[0124] According to the eleventh aspect, the electric motor is easily accessible during maintenance of the auxiliary propulsion device.

[0125] A watercraft according to a twelfth aspect of the present disclosure includes: a ship body; a main propulsion device that includes a main prime mover and applies at least a forward propulsive force to the ship body on the basis of power of the main prime mover; and an auxiliary propulsion device that includes an auxiliary prime mover and applies, to the ship body, a propulsive force in a direction different from the propulsive force applied by the main propulsion device on the basis of power of the auxiliary prime mover. The auxiliary prime mover is disposed in an attitude of having a longitudinal direction extending on a plane orthogonal to an up-down direction of the ship body.

[0126] According to the twelfth aspect, an upper end position of the auxiliary prime mover, which is a heavy object, can be suppressed to be low, and the center of gravity of the watercraft can be suppressed to be low. As a result, stability during sliding of the watercraft can be improved.

Examples

Embodiment Construction

Overall Configuration of Personal Watercraft

[0020]FIG. 1 is a partially broken side view of a watercraft 1 according to an embodiment of the present disclosure, FIG. 2 is a plan view of the watercraft 1 as viewed from above, and FIG. 3 is a schematic front view of the watercraft 1 as viewed from the front. In the present embodiment, the watercraft 1 is a jet propulsion and riding type personal watercraft that jets a water flow to move over the water in reaction thereto. The watercraft 1 includes a ship body 10, a main propulsion device 2, and an auxiliary propulsion device 3. Hereinafter, the watercraft 1 will be appropriately abbreviated as a PWC1.

[0021]Here, front, rear, left, right, up, and down directions displayed in each figure are based on a driver M (FIG. 1) riding in the PWC1. In addition, a front-rear direction, a left-right direction, and an up-down direction of the PWC1 or the ship body 10 are defined on the basis of these respective directions. Namely, the front-rear di...

Claims

1. A watercraft comprising:a ship body;a main propulsion device including a jet pump that jets a jet water flow from the ship body; andan auxiliary propulsion device including a propeller disposed in a tunnel penetrating the ship body in a ship width direction that is a width direction of the ship body, and an electric motor that rotationally drives the propeller, the electric motor having a motor shaft extending on a plane orthogonal to an up-down direction of the ship body.

2. The watercraft according to claim 1, wherein the electric motor has the motor shaft extending in the ship width direction.

3. The watercraft according to claim 1, wherein the electric motor is disposed at a position intersecting a width center plane that divides the ship body into two equal parts in the ship width direction.

4. The watercraft according to claim 1, wherein the electric motor and the propeller are disposed at positions intersecting a common perpendicular plane orthogonal to the ship width direction.

5. The watercraft according to claim 4, wherein the electric motor is disposed above or below the propeller.

6. The watercraft according to claim 2, whereinthe auxiliary propulsion device further includes a power transmission mechanism that transmits rotation of the motor shaft to the propeller, andthe electric motor and the propeller are disposed on one side of the power transmission mechanism in the ship width direction.

7. The watercraft according to claim 6, wherein the power transmission mechanism functions as a speed booster that accelerates rotation of the motor shaft and transmits the rotation to the propeller.

8. The watercraft according to claim 1, wherein the electric motor is disposed in an attitude of having a longitudinal direction parallel to a rotation axis of the propeller.

9. The watercraft according to claim 1, wherein the electric motor is directly or indirectly supported by a tubular tunnel wall forming the tunnel.

10. The watercraft according to claim 1, further comprising: a storage capable of storing luggage and provided above the electric motor.

11. The watercraft according to claim 1, whereinthe ship body has a motor housing part that houses the electric motor, andthe motor housing part has an opening that enables external access to the electric motor.

12. A watercraft comprising:a ship body;a main propulsion device that includes a main prime mover and applies at least a forward propulsive force to the ship body on the basis of power of the main prime mover; andan auxiliary propulsion device that includes an auxiliary prime mover and applies, to the ship body, a propulsive force in a direction different from the propulsive force applied by the main propulsion device on the basis of power of the auxiliary prime mover, the auxiliary prime mover being disposed in an attitude of having a longitudinal direction extending on a plane orthogonal to an up-down direction of the ship body.

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