Planing boat

Abstract

To improve the stability of the planing boat while it is planing. [Solution] The planing boat comprises a hull, a main propulsion system including a jet pump that ejects a jet stream of water from the hull, and an auxiliary propulsion system (3) including a propeller (52) located in a tunnel (5) that penetrates the hull in the width direction and an electric motor (51) that rotates the propeller (52). The electric motor (51) has a motor shaft (513) that extends on a plane perpendicular to the vertical direction of the hull.

Description

[[Technical Field]]

[0001] The present disclosure relates to a planing boat. [[Background Art]]

[0002] As a planing boat propelled by a jet water stream, one described in the following Patent Document 1 is known. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] US Patent Application Publication No. 2013 / 0102206 Specification [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] In a planing boat as described above, high stability during planing is desired.

[0005] An object of the present disclosure is to provide a planing boat having high stability during planing. [[Means for Solving the Problem]]

[0006] To solve the above problem, a planing boat according to one aspect of the present disclosure includes: a hull; a main propulsion device including a jet pump that jets a jet water stream from the hull; and an auxiliary propulsion device including a propeller disposed in a tunnel penetrating the hull in a beam direction which is the width direction of the hull, and an electric motor that rotationally drives the propeller, wherein the electric motor has a motor shaft extending on a plane orthogonal to the vertical direction of the hull.

[0007] A planing boat according to another aspect of the present disclosure comprises a hull, a main propulsion system including a main motor that imparts at least forward thrust to the hull based on the power of the main motor, and an auxiliary propulsion system including an auxiliary motor that imparts thrust to the hull in a direction different from the thrust of the main propulsion system based on the power of the auxiliary motor, wherein the auxiliary motor is positioned such that its longitudinal direction extends on a plane perpendicular to the vertical direction of the hull. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a planing boat with high stability during planing. [Brief explanation of the drawing]

[0009] [Figure 1] This is a partially broken side view of a small planing boat according to one embodiment of the present disclosure. [Figure 2] This is a plan view of the small planing boat shown above, seen from above. [Figure 3] This is a schematic front view of the small planing boat shown above, seen from the front. [Figure 4] This is a side cross-sectional view showing the front section of the small planing boat described above in a partially broken state. [Figure 5] This diagram schematically illustrates the operating modes of the small planing boat described above. [Figure 6] This is a perspective view of the auxiliary propulsion system. [Figure 7] This is a front view of the above-mentioned auxiliary propulsion device, seen from the front. [Figure 8] This is a cross-sectional view of the auxiliary propulsion device shown above, corresponding to Figure 7. [Figure 9] This is a side view of the above auxiliary propulsion device, taken from the right. [Figure 10] This is a side view of the above-mentioned auxiliary propulsion device, seen from the left. [Figure 11] This figure corresponds to Figure 8, showing a first modified example of the present disclosure. [Figure 12] This figure corresponds to Figure 7, showing a second modified example of the present disclosure. [Modes for carrying out the invention]

[0010] [Overall configuration of a small planing boat] Figure 1 is a partially cutaway side view of a planing boat 1 according to one embodiment of the present disclosure, Figure 2 is a top view of the planing boat 1, and Figure 3 is a schematic front view of the planing boat 1 viewed from the front. In this embodiment, the planing boat 1 is a jet-propelled, rideable small planing boat (personal watercraft) that moves on the water by ejecting a stream of water and using the reaction force. The planing boat 1 comprises a hull 10, a main propulsion device 2, and an auxiliary propulsion device 3. Hereinafter, the planing boat 1 will be abbreviated as PWC1 as appropriate.

[0011] Here, the forward, backward, left, right, up, and down directions shown in each figure are based on the driver M (Figure 1) boarding PWC1. Based on these directions, the longitudinal, lateral, and vertical directions of PWC1 or hull 10 are defined. That is, the longitudinal direction is along the longitudinal direction of hull 10, with the bow being forward and the stern being aft. When PWC1 is stationary and there are no crew or cargo on board, the longitudinal direction can be defined as the direction extending parallel to the longitudinal direction of hull 10 along the horizontal plane. The lateral direction is perpendicular to the longitudinal direction and parallel to the width direction of hull 10, with the driver M's left hand being left and the driver M's right hand being right. The vertical direction is perpendicular to the longitudinal and lateral directions (width direction), with the side facing the sky being up and the opposite side (facing the water) being down. When PWC1 is stationary and unoccupied with passengers and cargo, the vertical direction can be defined as the direction parallel to the vertical line.

[0012] The hull 10 comprises a hull 11 that forms the lower part of the hull 10, and a deck 12 positioned above the hull 11. The upper surface of the hull 11 is open. The deck 12 covers the opening on the upper surface of the hull 11 and is joined to the opening edge of the hull 11 along its entire circumference. That is, a gunwale 10G, which is the joining line between the hull 11 and the deck 12, is formed around the periphery of the hull 10.

[0013] A steering handle 13 and a seat 14 are arranged on a deck 12. The steering handle 13 is attached to a front portion of the deck 12. The steering handle 13 includes, for example, a handle bar that is rotatable about an axis extending substantially in a vertical direction and extends in a ship width direction (left-right direction), and a speed adjustment throttle lever attached to one end of the handle bar. The seat 14 is arranged behind the steering handle 13 so as to cover an area including the central portion of the deck 12. The seat 14 only needs to be a seat on which at least the driver M can sit. That is, the seat 14 may be a multi-person seat on which not only the driver M but also a passenger can sit, or may be a single-person seat on which only the driver M can sit.

[0014] Fig. 4 is a side cross-sectional view showing a front portion of PWC1 in a partially broken state. As shown in this figure, a luggage compartment 6 is built into the front portion of a hull 10. The luggage compartment 6 functions as a storage compartment for storing luggage and the like of crew members including the driver M, and is defined by a box-shaped luggage compartment wall 61. The luggage compartment 6 or the luggage compartment wall 61 is arranged in a space between a hull 11 and the deck 12 at the front portion of the hull 10 so as to occupy most of the space. The luggage compartment 6 corresponds to "storage" in the present disclosure.

[0015] A power room ER is formed behind the luggage compartment 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 portion to the central portion of the hull 10. A fuel tank 23 is arranged at a position in the front portion of the power room ER and immediately behind the luggage compartment 6. The fuel tank 23 is a tank that stores fuel to be supplied to the power source (an engine 21 to be described later) of the main propulsion device 2.

[0016] A front hatch 16 is attached to a front portion of the deck 12. The front hatch 16 is a lid that covers the cargo compartment 6 so that the cargo compartment 6 can be opened and closed. That is, a cargo compartment opening A1 for loading and unloading cargo is formed on the upper surface of the cargo compartment wall 61, and the front hatch 16 is attached to the front portion of the deck 12 so as to cover the cargo compartment opening A1 from above. A front end portion of the front hatch 16 is pivotally supported on the deck 12 via a hinge 16H, so that the front hatch 16 is attached so as to be vertically rotatable about the hinge 16H as indicated by an arrow Y1 in FIG. 4. That is, the front hatch 16 is attached to the deck 12 so as to be displaceable between a closed state shown by a solid line and an open state shown by an imaginary line in FIG. 4.

[0017] As shown in FIG. 1 and FIG. 2, the main propulsion device 2 includes an engine 21 serving as a power source and a jet pump 4 that generates a jet water flow. As also shown in FIG. 4, the engine 21 is housed behind a fuel tank 23 in a power chamber ER. The engine 21 is arranged near the center of a hull 10 in the front-rear direction. The jet pump 4 is arranged at a rear portion of the hull 10.

[0018] 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 four-stroke multi-cylinder engine driven by using gasoline as a fuel. The engine 21 includes a crankshaft 22 extending in the front-rear direction as an output shaft. Note that the engine 21 corresponds to the "main prime mover" in the present disclosure.

[0019] The jet pump 4 is arranged 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 about its 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 about the axis to generate a jet water flow.

[0020] The hull 10 includes an impeller passage 47 in which a jet pump 4 is located. The impeller passage 47 includes a water intake 48 for taking in water (e.g., seawater) from the landing area of ​​the PWC 1. The water intake 48 is formed in the center of the width direction on the aft bottom surface of the hull 11. The impeller passage 47 is formed to penetrate the aft part of the hull 11 in the longitudinal direction. The jet pump 4 pressurizes and accelerates the water taken in by the impeller passage 47 and ejects it aft to provide thrust to the PWC 1.

[0021] 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 supplied from the impeller 42 to generate a jet stream. The venturi nozzle 43 is located behind the impeller passage 47 and has a flow path cross-sectional area that gradually narrows towards the rear to increase the flow velocity. The jet nozzle 44 has an injection port 45 that opens to the rear as the outlet for the jet stream. The jet nozzle 44 is connected to the rear end of the venturi nozzle 43 so as to be able to swing from side to side about an axis that extends vertically. The jet nozzle 44 is driven to swing by a nozzle motor 44M. When the jet nozzle 44 swings, the direction of the jet stream ejected from the injection port 45 is changed to the left or right. The nozzle motor 44M is driven, for example, in response to steering of the steering handle 13.

[0022] The jet nozzle 44 may also be mounted so as to be able to swing up and down around an axis extending in the width direction (left-right direction) of the ship. This up-and-down swinging function of the jet nozzle 44 allows for adjustment of the planing attitude of the PWC1. For example, the more the jet nozzle 44 is tilted downward by the swing, the higher the bow height of the PWC1 can be raised when planing.

[0023] The reverse bucket 46 has the function of switching the propulsion direction of the PWC 1 forward or backward. The reverse bucket 46 is positioned near the nozzle 45 and is attached to the jet nozzle 44 so as to be rotatable around an axis extending in the left-right direction. When the reverse bucket 46 descends to cover the nozzle 45, the jet stream is redirected forward, and the propulsion direction of the PWC 1 is changed to backward.

[0024] The auxiliary propulsion device 3 generates a water flow in the ship's width direction (left-right direction), that is, a water flow from the front of the hull 10 toward the left or right. This water flow imparts thrust to the hull 10 in the ship's width direction. In this embodiment, an example is shown in which a water flow is ejected straight in the ship's width direction from the auxiliary propulsion device 3, but the water flow may also be directed in a direction that is inclined with respect to the ship's width direction.

[0025] The hull 10 is provided with a tunnel 5 at a position corresponding to the auxiliary propulsion device 3. The tunnel 5 is a passage that extends linearly through the hull 11 in the width direction at the front of the hull 10. The tunnel 5 is defined by a tunnel wall 50 (Figure 4), which is a cylindrical wall extending in the width direction. The tunnel 5 has openings at both ends. As shown in Figures 2 and 3, a first tunnel opening 5A is provided at one end of the tunnel 5, and a second tunnel opening 5B is provided at the other end. The first tunnel opening 5A opens on the left side of the front of the hull 11. The second tunnel opening 5B opens on the right side of the front of the hull 11. The first tunnel opening 5A and the second tunnel opening 5B are formed in front of the engine 21 and the jet pump 4.

[0026] Tunnel 5 is located forward of the steering wheel 13 and the fuel tank 23. In other words, in the longitudinal direction, tunnel 5 is located between the steering wheel 13 (or fuel tank 23) and the bow.

[0027] Furthermore, the first tunnel opening 5A and the second tunnel opening 5B of tunnel 5 are located below the waterline, at least when the PWC1 is stationary or moving at a slow speed in a non-planing state. In other words, the tunnel openings 5A and 5B are located at a height close to the bottom of the hull. For example, the upper ends of the tunnel openings 5A and 5B are located below the upper ends of the engine 21 and fuel tank 23. As a result, the height of tunnel 5 is relatively low, making it easier to place components such as the electric motor 51, which will be described later, above tunnel 5.

[0028] On the other hand, when PWC1 is gliding, the tunnel openings 5A and 5B may be located above the water surface. If the tunnel openings 5A and 5B are located above the water surface, it is prevented that the tunnel openings 5A and 5B will become a drag element during gliding.

[0029] The auxiliary propulsion device 3 discharges fluid from inside the tunnel 5 to the outside of the hull 10 through the first tunnel opening 5A or the second tunnel opening 5B, generating thrust in the width direction of the vessel through the reaction force. The discharged fluid is basically water (e.g., seawater) from the landing area of ​​the PWC 1, but may also contain air. In this specification, the flow of fluid discharged from inside the tunnel 5 in this manner is simply referred to as water flow.

[0030] The auxiliary propulsion system 3 mainly includes an electric motor 51, a propeller 52, and a gear mechanism 53, as shown in Figure 3. The electric motor 51 is a power source for obtaining thrust in the width direction of the ship and rotates the propeller 52. The electric motor 51 may be an AC motor or a DC motor. The propeller 52 is located inside the tunnel 5 and rotates within the tunnel 5. The gear mechanism 53 transmits the driving force of the electric motor 51 to the propeller 52. That is, when the electric motor 51 is driven, the power of the electric motor 51 is transmitted to the propeller 52 via the gear mechanism 53, causing the propeller 52 to rotate. The rotation of the propeller 52 generates a water flow inside the tunnel 5, and the discharge of this water flow generates thrust in the width direction of the ship. The electric motor 51 corresponds to the "auxiliary prime mover" in this disclosure, and the gear mechanism 53 corresponds to the "power transmission mechanism" in this disclosure.

[0031] Figure 5 schematically shows the operating modes of PWC1. Figure 5 illustrates the operating modes of planing, turning, and lateral movement. In planing mode, the main propulsion system 2 operates, and a jet of water is ejected from the jet pump 4 backward, as shown by arrow F1. Receiving the forward thrust force applied to the rear of the hull 10 by the reaction of this jet of water, PWC1 moves forward, as shown by arrow D1. When the reverse bucket 46 operates and covers the nozzle 45, PWC1 is propelled backward.

[0032] Furthermore, in planing mode, the PWC1 can be made to orbit and turn by steering the steering handle 13. That is, the leftward or rightward swing of the jet nozzle 44 in conjunction with the steering handle 13 changes the direction of the jet stream to either the left or the right, and the PWC1 orbits and turns accordingly. For example, if the jet nozzle 44 is swung to the right by the steering handle 13, the jet stream is ejected diagonally to the right and rear, as shown by arrow F1A. Receiving a thrust force diagonally to the left and forward from the rear of the hull 10 due to the reaction of this jet stream, the PWC1 orbits and turns to the right, as shown by arrow D1A. Conversely, if the jet nozzle 44 is swung to the left, the PWC1 orbits and turns to the left. During such orbital turns, the driver M, while straddling the seat 14, may shift his weight to tilt the hull 10 around an axis extending in the front-to-back direction, that is, to bank the hull 10 to either the left or right, in order to counteract the centrifugal force associated with the orbital turn.

[0033] In turning mode, the main propulsion system 2 is deactivated and the auxiliary propulsion system 3 is activated, causing the PWC 1 to turn in a stationary position. For example, as shown by arrow F2 in Figure 5, when the auxiliary propulsion system 3 is activated so that water is discharged to the left from the first tunnel opening 5A, the reaction of this water flow imparts a thrust to the rightward direction to the front of the hull 10. Receiving this thrust, the PWC 1 turns clockwise around its center of gravity G as the center of rotation, as shown by arrow D2. Conversely, when the auxiliary propulsion system 3 is activated so that water is discharged to the right from the second tunnel opening 5B, a thrust is imparted to the leftward direction to the front of the hull 10, causing the PWC 1 to turn counterclockwise.

[0034] Although not shown in Figure 5, in addition to the above-mentioned gliding mode and turning mode, there may also be an operating mode in which both the main propulsion unit 2 and the auxiliary propulsion unit 3 are in operation.

[0035] [Details of the auxiliary propulsion system] Further details of the auxiliary propulsion device 3 will be explained. Figure 6 is a perspective view of the auxiliary propulsion device 3, Figure 7 is a front view of the auxiliary propulsion device 3 seen from the front, Figure 8 is a cross-sectional view of the auxiliary propulsion device 3 corresponding to Figure 7, Figure 9 is a side view of the auxiliary propulsion device 3 seen from the right, and Figure 10 is a side view of the auxiliary propulsion device 3 seen from the left. As shown in each figure, the electric motor 51 is located on the outside of the tunnel 5, near the center of the tunnel 5 in the width direction (left-right direction). In this embodiment, the electric motor 51 is located above the tunnel 5, facing the top surface of the tunnel wall 50 with a slight distance between them.

[0036] The electric motor 51 includes a cylindrical motor case 511, an electric unit 512 containing electromagnetic components such as a rotor and 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.

[0037] The motor shaft 513 extends in the direction of the ship's width. That is, the electric motor 51 is positioned such that the motor shaft 513 extends in the direction of the ship's width, or in other words, the motor shaft 513 extends on a plane perpendicular to the vertical direction. The direction of extension of the motor shaft 513 is parallel to the tunnel axis, which is the central axis of the tunnel 5. One end of the motor shaft 513 is fixed to the rotor in the electric unit 512. In this embodiment, the right end of the motor shaft 513 extending in the direction of the ship's width (left-right direction) is fixed to the rotor, and the motor shaft 513 extends to the left from the electric unit 512 toward the outside of the motor case 511. A part of the motor shaft 513 extending toward the outside of the motor case 511 is inserted inside the upper part of the gear mechanism 53 (the first case part 531a, which will be described later). When the electric motor 51 is driven, the rotor rotates relative to the stator due to the application of power, and the motor shaft 513 rotates integrally with the rotor.

[0038] The electric motor 51 has a long shape in the same direction as its longitudinal direction, such that the direction in which its motor shaft 513 extends is the ship's width direction (left-right direction). In other words, the electric motor 51 is positioned so that its longitudinal direction extends on a plane perpendicular to the vertical direction.

[0039] The propeller 52 has an impeller 521 that can rotate within the tunnel 5 and a propeller shaft 522 (rotation shaft) coaxially coupled to the impeller 521.

[0040] The propeller shaft 522 extends in the width direction within the tunnel 5. That is, the propeller 52 is positioned such that the propeller shaft 522 extends in the width direction, or in other words, the propeller shaft 522 extends on a plane perpendicular to the vertical direction. The propeller shaft 522 is positioned at the center of the tunnel 5, that is, at the center of the circular cross-section of the tunnel 5.

[0041] The impeller 521 has a boss 521a fixed to one end of the propeller shaft 522, and a plurality of vanes 521b extending radially outward from the circumferential surface of the boss 521a. In this embodiment, the propeller shaft 522 is positioned to protrude to the right from the inside of the lower part of the gear mechanism 53 (the second case portion 531b described later) located inside the tunnel 5, and the boss 521a of the impeller 521 is fixed to the right end of this propeller shaft 522. The propeller shaft 522 rotates by receiving rotational force transmitted from the electric motor 51 via the gear mechanism 53. The impeller 521 generates a water flow by rotating together with the propeller shaft 522.

[0042] As described above, in this embodiment, both the motor shaft 513 and the propeller shaft 522 extend in the direction of the ship's width. That is, the electric motor 51 and the propeller 52 are arranged such that the motor shaft 513 and the propeller shaft 522 are parallel to each other. Alternatively, the electric motor 51 is arranged such that its longitudinal direction is parallel to the propeller shaft 522.

[0043] The gear mechanism 53 mainly comprises a gear case 531 and a first gear 532 and a second gear 533 housed within the gear case 531, as shown in Figure 8.

[0044] The first gear 532 is fitted onto the motor shaft 513 so as to rotate integrally with the motor shaft 513. The second gear 533 is fitted onto the propeller shaft 522 so as to rotate integrally with the propeller shaft 522. Both the first gear 532 and the second gear 533 are spur gears with numerous straight teeth formed on their outer surfaces. The two gears 532 and 533 mesh together so as to rotate in conjunction with each other.

[0045] The gear mechanism 53 may function as either a speed reducer or a speed increaser, but in this embodiment, the gear mechanism 53 functions as a speed increaser. That is, the outer diameter of the first gear 532 is larger than the outer diameter of the second gear 533. When the rotation of the first gear 532 is transmitted to the second gear 533, the second gear 533 rotates at a faster speed than the first gear 532. In other words, the gear mechanism 53 in this embodiment increases the speed of the rotation of the motor shaft 513 and transmits it to the propeller shaft 522.

[0046] The gear case 531 has a first case section 531a that houses the first gear 532 and a second case section 531b that houses the second gear 533. The second case section 531b is located inside the tunnel 5. The second case section 531b is approximately circular in a view in the ship's width direction, and its outer diameter is smaller than the diameter of the tunnel 5. The first case section 531a is circular in a view in the ship's width direction, and has a larger outer diameter than the second case section 531b, and is connected to the upper part of the second case section 531b. The majority of the upper part of the first case section 531a is located outside the tunnel 5, while a portion of the lower part extends inside the tunnel 5 and connects to the second case section 531b.

[0047] A bearing 535 that rotatably supports the motor shaft 513 is located inside the first case section 531a. A bearing 536 that rotatably supports the propeller shaft 522 is located inside the second case section 531b.

[0048] The gear case 531 has a first fixing part 531c that functions as a fixing part to the electric motor 51 and a second fixing part 531d that functions as a fixing part to the tunnel wall 50. The first fixing part 531c is formed in a cylindrical shape that protrudes to the right from the first case part 531a toward the electric motor 51. The first fixing part 531c and the motor case 511 are connected to each other by bolts or the like via a flange 55. The second fixing part 531d is formed in a rectangular frame shape when viewed from above, surrounding the lower part of the first case part 531a. The second fixing part 531d is fixed to the base 50a, which is formed in the center of the tunnel wall 50 in the width direction of the ship, while resting on the upper surface of the base 50a. The base 50a has a shape similar to an arched gate and is formed to protrude radially outward from the upper half of the central part of the tunnel wall 50. A rectangular opening is formed on the upper surface of the base 50a, corresponding to the opening on the lower surface of the second fixing part 531d when viewed from above. The second fixing part 531d is joined to the base 50a from above by appropriate means such as welding. As a result, the gear case 531 is fixed to the tunnel wall 50 with a portion of its lower side, including the second case part 531b, protruding into the tunnel 5.

[0049] As described above, in this embodiment, the gear case 531 is fixed to the tunnel wall 50, and the motor case 511 is fixed to the gear case 531. In other words, the electric motor 51 is indirectly supported by the tunnel wall 50 via the gear case 531.

[0050] The electric motor 51 and propeller 52 are positioned on one side of the gear mechanism 53 in the ship's width direction (left-right direction). The electric motor 51 and propeller 52 may be positioned on either the left or right side of the gear mechanism 53, but in this embodiment, both are positioned on the right side of the gear mechanism 53. For example, the electric motor 51 is positioned on the right side of the gear mechanism 53 by fixing its motor case 511 to the upper part (first case portion 531a) of the gear case 531 from the right. The propeller 52 is also positioned on the right side of the gear mechanism 53 by supporting the propeller shaft 522 inserted from the right into the lower part (second case portion 531b) of the gear case 531.

[0051] When the auxiliary propulsion device 3 is in use, for example, when the auxiliary propulsion device 3 is activated to perform the turning mode shown in Figure 5, the propeller 52 rotates due to the drive of the electric motor 51, and a water flow is generated inside the tunnel 5. That is, when the motor shaft 513 rotates due to the drive of the electric motor 51, the first gear 532 fixed to the motor shaft 513 rotates, and the second gear 533 that meshes with the first gear 532 also 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 inside the tunnel 5, and this water flow is discharged from the tunnel 5 in either the left or right direction.

[0052] Here, the direction of the water flow discharged from tunnel 5 is determined by the 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 direction, the propeller 52 rotates so that a water flow is generated from left to right inside tunnel 5. That is, as shown by the white arrows in Figure 6, fluid is taken in from the first tunnel opening 5A and discharged to the right from the second tunnel opening 5B. The reaction force from this discharge becomes the thrust that moves PWC1 to the left. On the other hand, when the electric motor 51 is driven so that the motor shaft 513 rotates in the opposite direction to the forward direction, the propeller 52 rotates so that a water flow is generated from right to left inside tunnel 5. That is, contrary to the white arrows in Figure 6, fluid is taken in from the second tunnel opening 5B and discharged to the left from the first tunnel opening 5A. The reaction force from this discharge becomes the thrust that moves PWC1 to the right.

[0053] The plane CP shown in Figures 3, 7, and 8 is the width-center plane that divides the hull 10 into two equal parts in the width direction. This width-center plane CP is a plane that extends vertically through the center of gravity G of the PWC1 and is perpendicular to the width direction. That is, when viewed from the front in a normal state when the hull 10 is not tilted to the left or right, the width-center plane CP coincides with the vertical line passing through the center of gravity G. The electric motor 51 and propeller 52 in the auxiliary propulsion device 3 are positioned at locations that intersect this width-center plane CP.

[0054] Specifically, the electric motor 51 is positioned near the center in the width direction of the hull 10 such that the width center plane CP intersects with one of the parts of the electric motor 51. Here, the axis X1 shown in Figure 8 is the motor central axis, which is the center of the motor shaft 513, and the direction along this motor central axis X1 is defined as the axial direction of the electric motor 51. The axial direction of the electric motor 51 is here synonymous with the longitudinal direction of the electric motor 51. In this embodiment, the electric motor 51 is positioned such that the width center plane CP intersects with the midpoint of the axial direction of the electric motor 51. That is, the width center plane CP is located between the right end of the motor case 511, which is one end of the electric motor 51 in the axial direction, and the left end of the motor shaft 513, which is the other end of the electric motor 51 in the axial direction. More specifically, the width center plane CP is located between the axial end and the other end of the motor case 511 in the axial direction. In other words, the electric motor 51 is positioned so that it intersects with the width center plane CP at the midpoint of the axial direction of the motor case 511. More preferably, the electric motor 51 is positioned such that the width center plane CP passes through the center of gravity of the electric motor 51.

[0055] Similarly, the propeller 52 is positioned near the center in the width direction of the hull 10 such that the width center plane CP intersects with any part of the propeller 52. Here, the axis X2 shown in Figure 8 is the propeller central axis, which is the center of the propeller shaft 522, and the direction along this propeller central axis X2 is defined as the axial direction of the propeller 52. In this embodiment, the propeller 52 is positioned such that the width center plane CP intersects with the midpoint of the axial direction of the propeller 52. That is, the width center plane CP is located between the right end of the impeller 521, which is one axial end of the propeller 52, and the left end of the propeller shaft 522, which is the other axial end of the propeller 52. More specifically, the width center plane CP is located at the position corresponding to the vane 521b of the impeller 521. In other words, the propeller 52 is positioned so as to intersect the width center plane CP at the position of the vane 521b.

[0056] As described above, the electric motor 51 and the propeller 52 are located at positions that intersect with a common width center plane CP. Furthermore, the electric motor 51 is positioned above the tunnel 5, and the propeller 52 is positioned inside the tunnel 5. In other words, the electric motor 51 and the propeller 52 are positioned such that, near the width center of the hull 10, the electric motor 51 is positioned above the propeller 52, with the tunnel wall 50 in between.

[0057] As shown in Figure 4, the electric motor 51 is positioned in a side view between the rear of the cargo compartment wall 61 (cargo compartment 6) and the front of the fuel tank 23. In other words, the hull 10 has a motor housing S1 for housing the electric motor 51 between the cargo compartment wall 61 and the fuel tank 23.

[0058] The cargo compartment wall 61 has a shielding portion 61a that covers the electric motor 51 from above. The shielding portion 61a has an access opening A2 that allows access to the electric motor 51 during maintenance of the auxiliary propulsion device 3. A cover member 62 that closes the access opening A2 is detachably attached to the cargo compartment wall 61. That is, during maintenance of the auxiliary propulsion device 3, the worker opens the front hatch 16 and removes the cover member 62. This makes it possible to access the electric motor 51 from the outside through the cargo compartment opening A1 and the access opening A2. In other words, in this embodiment, the electric motor 51 is housed in a motor housing portion S1 with an access opening A2 in order to ensure access to the electric motor 51 even when the cargo compartment 6 is located above the electric motor 51.

[0059] Although not shown in the drawing, a battery for storing the power supplied to the electric motor 51 may be placed near the electric motor 51. For example, the battery may be positioned so as to be aligned with the electric motor 51 in the axial direction of the tunnel 5, that is, in the direction of the ship's width. Alternatively, the battery may be positioned at the rear of the tunnel 5, lower than the upper end of the electric motor 51.

[0060] [Effects and Effects] As described above, in this embodiment, the electric motor 51, which is the power source of the auxiliary propulsion device 3, is positioned so that its motor shaft 513 extends in the direction of the ship's width. Therefore, compared to the case where the motor shaft 513 extends in the vertical direction, the stability of the PWC 1 during planing can be improved.

[0061] In other words, in this embodiment, the electric motor 51 is positioned so that the motor shaft 513 extends in the direction of the ship's width, or in other words, so that the motor shaft 513 extends on a plane perpendicular to the vertical direction. Compared to the case where the electric motor 51 is positioned so that the motor shaft 513 extends in the vertical direction, the upper end position of the heavy electric motor 51 can be kept lower. As a result, the center of gravity G of the PWC1 can be kept low, improving the stability of the PWC1 when it is planing. Furthermore, the improved stability can improve the operability of the PWC1.

[0062] In this PWC1, the width dimension of the hull 10, which is the lateral dimension, is significantly smaller than the length dimension of the hull 10, which is the longitudinal dimension. In other words, in PWC1, the ratio of the width dimension to the length dimension of the hull 10 is often smaller than that of a typical vessel. For this reason, PWC1 tends to roll from side to side due to the effects of waves and wind on the water. In contrast, according to this embodiment, in which the center of gravity G of PWC1 is kept low, the tendency of PWC1 to roll from side to side can be reduced, and in that sense, the stability of PWC1 can be improved.

[0063] Furthermore, in PWC1, the operator M may bank the hull 10 to the left or right by shifting their weight during orbital turns, but such banking operations can be difficult, especially for beginners. In contrast, according to this embodiment, in which the center of gravity G of PWC1 is kept low, excessive changes in the attitude of PWC1 associated with banking operations are suppressed, making banking operations easier and thus improving the operability of PWC1.

[0064] Furthermore, in PWC1, when moving forward using the main propulsion system 2, as the speed of movement increases, the vessel transitions to a planing state in which it moves gliding across the water surface with its bow lifted. In this case, according to this embodiment, in which the center of gravity G of PWC1 is kept low, the bow is more likely to lift out of the water surface, thus promoting the transition of PWC1 to a planing state.

[0065] Furthermore, since the motor shaft 513 extends in the width direction of the ship, the electric motor 51 can be positioned along the tunnel 5. This reduces the amount by which the electric motor 51 protrudes from the tunnel 5 in the radial direction around the central axis (tunnel axis) of the tunnel 5. In particular, when the electric motor 51 is positioned above the tunnel 5 as in this embodiment, the amount by which the electric motor 51 protrudes from the tunnel 5 in the longitudinal direction can be reduced. In other words, according to this embodiment, in which the electric motor 51 is positioned so that the motor shaft 513 extends parallel to the tunnel axis, the auxiliary propulsion device 3 including the electric motor 51 can be made more compact in the radial direction (or longitudinal direction) of the tunnel 5.

[0066] Furthermore, in this embodiment, the electric motor 51 and propeller 52 are positioned at a location that intersects with the width center plane CP, which is a common vertical plane perpendicular to the ship's width direction. In other words, the electric motor 51 and propeller 52 are arranged in a layout such that the power transmission path from the electric motor 51 to the propeller 52 folds back in a U-shape. With this configuration, since the electric motor 51 and propeller 52 are positioned close to each other in the ship's width direction, the dimensions of the auxiliary propulsion device 3 in the ship's width direction can be reduced compared to the case where the power transmission path is not U-shaped.

[0067] Furthermore, since the width center plane CP is a plane that divides the hull 10 into two equal parts in the width direction, by positioning the electric motor 51 at a location that intersects with this width center plane CP, a layout is achieved in which the heavy electric motor 51 is located near the width center of the hull 10. This makes it easier to bring the center of gravity G of the PWC1 closer to the width center of the hull 10, and improves the left-right weight balance of the PWC1.

[0068] Furthermore, since the propeller 52 is positioned at a location that intersects with the width center plane CP, that is, the propeller 52 is positioned near the center in the width direction of the ship within the tunnel 5, it becomes easier to achieve equivalent thrust regardless of whether the direction of the water flow caused by the rotation of the propeller 52 is set to the left or right, thereby improving the usability of the auxiliary propulsion device 3.

[0069] Furthermore, in this embodiment, both the motor shaft 513 and the propeller shaft 522 extend in the width direction of the ship and are arranged parallel to each other. With this configuration, unlike cases where the motor shaft 513 and the propeller shaft 522 are not parallel, such as when the motor shaft 513 is arranged to extend in the front-rear direction, the structure of the gear mechanism 53 that connects the motor shaft 513 and the propeller shaft 522 can be simplified.

[0070] Furthermore, in this embodiment, the electric motor 51 is positioned above the propeller 52 (tunnel 5). With this configuration, the longitudinal dimensions of the auxiliary propulsion device 3 can be reduced compared to when the electric motor 51 is positioned in front of or behind the propeller 52. Also, compared to when the electric motor 51 is positioned below the propeller 52, that is, between the tunnel 5 and the bottom of the hull, it becomes easier to bring the tunnel 5 closer to the bottom of the hull, making it easier to position the tunnel openings 5A and 5B below the waterline when the PWC1 is not planing.

[0071] Furthermore, in this embodiment, a gear mechanism 53 is provided to transmit the rotation of the motor shaft 513 to the propeller shaft 522, and both the electric motor 51 and the propeller 52 are positioned to the right of this gear mechanism 53. By positioning the electric motor 51 and the propeller 52 on the same side in the ship's width direction relative to the gear mechanism 53 in this way, the dimensions of the auxiliary propulsion device 3 in the ship's width direction can be reduced compared to when both are positioned on opposite sides of the gear mechanism 53.

[0072] Furthermore, in this embodiment, the gear mechanism 53 functions as a speed increaser that increases the rotation of the motor shaft 513 and transmits it to the propeller shaft 522. With this configuration, even if the electric motor 51 is relatively small or low-output, the rotation of the electric motor 51 can be transmitted to the propeller 52 via the gear mechanism 53 (speed increaser), allowing the propeller 52 to rotate at a rotational speed that generates thrust capable of moving the PWC 1.

[0073] Furthermore, in this embodiment, the electric motor 51 is indirectly supported by the tunnel wall 50 that constitutes the tunnel 5 via the gear case 531. By supporting the electric motor 51 using the tunnel wall 50 in this way, the structure of the auxiliary propulsion device 3 can be simplified.

[0074] Furthermore, in this embodiment, the cargo compartment 6 is positioned above the electric motor 51. By positioning the cargo compartment 6 above the electric motor 51, whose upper end position is kept low, sufficient capacity for the cargo compartment 6 can be secured.

[0075] Furthermore, an access opening A2 is formed in the shielding portion 61a of the cargo compartment wall 61 that covers the electric motor 51 from above, allowing external access to the electric motor 51. With this configuration, the electric motor 51 can be easily accessed through the access opening A2 during maintenance of the auxiliary propulsion device 3, thereby improving maintainability.

[0076] [Differentiation] While preferred embodiments of the present disclosure have been described above, the disclosure is not limited thereto, and variations such as the following are possible.

[0077] In the above embodiment, a gear mechanism 53 including a first gear 532 and a second gear 533 that mesh with each other was used as the power transmission mechanism to transmit the rotation of the motor shaft 513 to the propeller shaft 522, but the configuration of the power transmission mechanism is not limited to this. For example, one or more intermediate gears may be provided between the first gear 532 and the second gear 533. Also, 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. In other words, the gear mechanism 53 may function as a reduction gear rather than a speed increaser.

[0078] Furthermore, a power transmission mechanism other than gears may be used. For example, as shown in Figure 11, a power transmission mechanism 73 including a chain or belt may be used. Specifically, the power transmission mechanism 73 shown in Figure 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 consisting of a chain or belt wrapped 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 a power transmission mechanism 73 is used, the rotation of the motor shaft 513 can be appropriately transmitted to the propeller shaft 522. Moreover, since the outer diameters of the first pulley 732 and the second pulley 733 can be easily reduced, the upper end position of the gear case 731 can be kept lower compared to the above embodiment, which has the advantage of reducing the vertical dimension of the auxiliary propulsion device 3.

[0079] In the above embodiment, both the electric motor 51 and the propeller 52 were positioned at locations that intersect with the width center plane CP, which divides the hull 10 into two equal parts in the width direction. However, at least one of the electric motor 51 and the propeller 52 may be positioned at a location that does not intersect with the width center plane CP, that is, at a location away from the width center plane CP in the width direction.

[0080] In the above embodiment, the electric motor 51 was located on the outside of the cargo compartment 6, but the electric motor 51 may also be located inside the cargo compartment 6.

[0081] In the above embodiment, an example was shown in which the electric motor 51 and propeller 52 are arranged on one side of the gear mechanism 53 in the ship's width direction. However, the electric motor 51 and propeller 52 may be arranged on opposite sides of the ship's width direction, with the gear mechanism 53 in between. For example, as shown in Figure 12, the electric motor 51 may be arranged on the left side of the gear mechanism 53 and the propeller 52 on the right side of the gear mechanism 53. Of course, it is also possible to reverse the relative positions of the electric motor 51 and propeller 52 as shown in Figure 12.

[0082] In the above embodiment, the electric motor 51 was indirectly supported by the tunnel wall 50 via the gear case 531, but the electric motor 51 may also be directly supported by the tunnel wall 50.

[0083] In the above embodiment, the axial or longitudinal direction of the electric motor 51 was parallel to the ship's width direction (left-right direction). However, the axial or longitudinal direction of the electric motor 51 does not necessarily have to be parallel to the ship's width direction; it just needs to be in a direction that extends on a plane perpendicular to the vertical direction of the hull 10. For example, the axial or longitudinal direction of the electric motor 51 may be parallel to the front-rear direction, or it may be in a direction that intersects both the front-rear direction and the ship's width direction. In other words, the motor shaft 513 does not necessarily have to be parallel to the propeller shaft 522, and may be non-parallel to the propeller shaft 522. Even if the two are non-parallel, if a gear mechanism 53 is used, for example, a mechanism including a bevel gear, the rotation of the motor shaft 513 can be transmitted to the propeller shaft 522 without any problems via the mechanism.

[0084] In the above embodiment, an example was shown in which the electric motor 51 is positioned above the propeller 52 and outside the tunnel 5, but the electric motor may also be positioned coaxially with the propeller shaft 522. That is, the motor shaft and the propeller shaft may be positioned on the same axis extending in the ship's width direction within the tunnel 5. Alternatively, 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) positioned inside the tunnel 5.

[0085] In the above embodiment, an example was shown in which the propeller 52 is rotated by one electric motor 51, but multiple electric motors 51 may be used. For example, an electric motor for forward rotation and an electric motor for reverse rotation may be provided separately.

[0086] In the above embodiment, the electric motor 51 was positioned above the propeller 52 (tunnel 5), but the electric motor 51 may also be positioned below the propeller 52.

[0087] Furthermore, the electric motor 51 may be positioned in front of or behind the propeller 52 (tunnel 5). When the electric motor 51 is positioned behind the propeller 52, the position of the center of gravity G of the PWC1 is relatively closer to the stern, so the moment of inertia required to lift the bow out of the water surface is reduced, which can facilitate the transition of the PWC1 into a planing state.

[0088] In the above embodiment, an example was shown in which the main prime mover, which is the power source of the main propulsion system 2, is an internal combustion engine 21. However, the type of main prime mover is not limited to this. For example, the main prime mover may be an electric motor.

[0089] In the above embodiment, an example was shown in which the auxiliary prime mover, which is the power source of the auxiliary propulsion device 3, is an electric motor 51, but the type of auxiliary prime mover is not limited to this. For example, the auxiliary prime mover may be an internal combustion engine or a fluid motor that rotates in response to a fluid supply.

[0090] In the above embodiment, an example of applying the present disclosure to a small planing boat (PWC) 1, which is a jet-propelled and rideable vessel, was described. However, the present disclosure can be applied to any vessel capable of moving on the water in a planing state, and is not limited to small planing boats. For example, the present disclosure can also be applied to planing boats that obtain propulsion by means other than the ejection of a jet stream, such as the rotation of a propeller, or to planing boats that are steered using a steering wheel instead of a steering handle.

[0091] In the above embodiment, an example in which the present disclosure is applied to a PWC1 in which a cargo compartment 6 is provided at the front of the hull 10 has been described. However, the present disclosure is naturally also applicable to a planing boat in which the cargo compartment 6 is omitted.

[0092] [summary] The above embodiments and their modifications include the following disclosures.

[0093] A planing boat according to a first aspect of the present disclosure comprises a hull, a main propulsion system including a jet pump for ejecting a jet of water from the hull, an auxiliary propulsion system including a propeller disposed in a tunnel penetrating the hull in the width direction of the hull, and an electric motor for rotating the propeller. The electric motor has a motor shaft extending on a plane perpendicular to the vertical direction of the hull.

[0094] According to the first embodiment, by arranging the electric motor for the auxiliary propulsion system so that its motor shaft extends in a plane perpendicular to the vertical direction, the upper end position of the heavy electric motor can be kept lower compared to when the electric motor is arranged so that its motor shaft extends in the vertical direction. As a result, the center of gravity of the planing boat can be kept low, thereby improving the stability of the planing boat while it is planing.

[0095] In the second embodiment of the planing boat, the electric motor has a motor shaft that extends in the direction of the width of the vessel, as in the first embodiment.

[0096] According to the second embodiment, the electric motor can be arranged along the tunnel, and the amount by which the electric motor protrudes from the tunnel in the radial direction around the tunnel axis can be reduced.

[0097] In the third embodiment of the planing boat, the electric motor is positioned at a location that intersects with a width center plane that divides the hull into two equal parts in the width direction.

[0098] According to the third embodiment, since the electric motor is positioned near the center of the hull's width, the left-right weight balance of the planing boat can be improved.

[0099] In the fourth embodiment of the planing boat, the electric motor and the propeller are positioned to intersect a common vertical plane perpendicular to the width direction of the vessel, as in the first or second embodiment.

[0100] According to the fourth embodiment, since the electric motor and the propeller are arranged in similar positions in the ship's width direction, the dimensions of the auxiliary propulsion system in the ship's width direction can be reduced.

[0101] In the fifth embodiment of the planing boat, the electric motor is positioned above or below the propeller, as in the fourth embodiment.

[0102] According to the fifth embodiment, the longitudinal dimension of the auxiliary propulsion device can be reduced.

[0103] In the sixth embodiment of the planing boat, the auxiliary propulsion device further includes a power transmission mechanism that transmits the rotation of the motor shaft to the propeller, and the electric motor and the propeller are arranged on one side of the power transmission mechanism in the width direction of the vessel.

[0104] According to the sixth embodiment, since the electric motor and the propeller are arranged on the same side in the ship's width direction with respect to the power transmission mechanism, the dimensions of the auxiliary propulsion system in the ship's width direction can be reduced.

[0105] In the seventh embodiment of the planing boat, in the sixth embodiment, the power transmission mechanism functions as a speed increaser that increases the speed of the rotation of the motor shaft and transmits it to the propeller.

[0106] According to the seventh embodiment, even if the electric motor is relatively small or low-powered, the propeller can be rotated at a rotational speed that generates enough thrust to move the planing boat.

[0107] In the eighth embodiment of the planing boat, the electric motor is positioned such that its longitudinal direction is parallel to the axis of rotation of the propeller, as in the first to seventh embodiments.

[0108] According to the eighth aspect, the dimensions of the auxiliary propulsion device in a direction perpendicular to the axis of rotation of the propeller can be reduced.

[0109] In the ninth embodiment of the planing boat, the electric motor is supported directly or indirectly by the cylindrical tunnel wall forming the tunnel, as in the first to eighth embodiments.

[0110] According to the ninth embodiment, the structure of the auxiliary propulsion system can be simplified by supporting the electric motor using the tunnel wall.

[0111] The planing boat according to the tenth embodiment further comprises, in the first to ninth embodiments, a storage compartment for luggage located above the electric motor.

[0112] According to the tenth embodiment, since the storage is positioned above the electric motor, which has a low upper end position, it is easier to secure storage capacity.

[0113] In the eleventh embodiment, the planing boat, in the first to tenth embodiments, has a hull having a motor housing for housing the electric motor, and the motor housing has an opening that allows external access to the electric motor.

[0114] According to the eleventh embodiment, the electric motor can be easily accessed during maintenance of the auxiliary propulsion system.

[0115] A planing boat according to a twelfth aspect of the present disclosure comprises a hull, a main propulsion system including a main motor that imparts at least forward thrust to the hull based on the power of the main motor, and an auxiliary propulsion system including an auxiliary motor that imparts thrust to the hull in a direction different from the thrust of the main propulsion system based on the power of the auxiliary motor. The auxiliary motor is positioned such that its longitudinal direction extends on a plane perpendicular to the vertical direction of the hull.

[0116] According to the twelfth embodiment, the upper end position of the heavy auxiliary motor can be kept low, thereby lowering the center of gravity of the planing boat. This improves the stability of the planing boat while it is planing. [Explanation of symbols]

[0117] 1 Plane boat 2 Main propulsion system 3 Auxiliary propulsion device 4 Jet pump 5 tunnels 6. Cargo area (storage) 10 hull 21. Engine (main power source) 50 Tunnel wall 51 Electric motor (auxiliary motor) 52 Propeller 53. Gear mechanism (power transmission mechanism) 513 Motor shaft 522 Propeller shaft (rotating shaft) A2 Access opening (opening) CP width center plane S1 Motor housing

Claims

1. The hull and, The main propulsion system includes a jet pump that ejects a jet stream of water from the hull, The auxiliary propulsion system includes a propeller positioned in a tunnel penetrating the hull in the width direction of the hull, and an electric motor that rotates the propeller. The electric motor has a motor shaft that extends on a plane perpendicular to the vertical direction of the hull, in a planing boat.

2. In the planing boat according to claim 1, The electric motor is a planing boat having a motor shaft that extends in the direction of the ship's width.

3. In the planing boat according to claim 1 or 2, The electric motor is positioned at a location that intersects with a width center plane that divides the hull into two equal parts in the width direction, in a planing boat.

4. In the planing boat according to claim 1 or 2, A planing boat in which the electric motor and the propeller are positioned at a location that intersects with a common vertical plane perpendicular to the width direction of the vessel.

5. In the planing boat according to claim 4, A planing boat in which the electric motor is positioned above or below the propeller.

6. In the planing boat according to claim 2, The auxiliary propulsion device further includes a power transmission mechanism that transmits the rotation of the motor shaft to the propeller, A planing boat in which the electric motor and the propeller are arranged on one side of the power transmission mechanism in the direction of the ship's width.

7. In the planing boat according to claim 6, A planing boat, wherein the power transmission mechanism functions as a speed increaser that increases the rotation speed of the motor shaft and transmits it to the propeller.

8. In the planing boat according to claim 1 or 2, The electric motor is positioned such that its longitudinal direction is parallel to the axis of rotation of the propeller in the planing boat.

9. In the planing boat according to claim 1 or 2, The electric motor is supported directly or indirectly by the cylindrical tunnel wall forming the tunnel, in the planing boat.

10. In the planing boat according to claim 1 or 2, A planing boat further equipped with storage space for luggage above the aforementioned electric motor.

11. In the planing boat according to claim 1 or 2, The hull has a motor housing section for housing the electric motor, A planing boat, wherein the motor housing has an opening that allows external access to the electric motor.

12. The hull and, A main propulsion system including a main engine, which imparts at least forward thrust to the hull based on the power of the main engine, The vessel includes an auxiliary propulsion system that includes an auxiliary prime mover and applies a propulsion force to the hull in a direction different from the propulsion force provided by the main propulsion system based on the power of the auxiliary prime mover, The auxiliary motor is positioned so that its longitudinal direction extends on a plane perpendicular to the vertical direction of the hull, in a planing boat.

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