JP7742757B2 - ship - Google Patents

Description

This disclosure relates to ships.

For ships that require maneuverability within a harbor, there are known ships equipped with azimuth thrusters at the stern. However, such azimuth thrusters increase the ship's hull resistance, which can lead to increased fuel consumption.
Patent Document 1 describes a ship equipped with a single-shaft controllable pitch propeller as a main propeller and an azimuth thruster positioned directly beside the controllable pitch propeller as an auxiliary propeller. Patent Document 1 proposes a technology for reducing the additional resistance of the hull by providing a liftable azimuth thruster that is lowered only when the ship is maneuvering to enter or leave a port and stored within the hull at other times.

Patent No. 6618869

However, if the azimuth thruster is made movable as in Patent Document 1, a long vertical space is required inside the hull to store the azimuth thruster. This means that the space above the azimuth thruster inside the hull cannot be used, and if, for example, there is a vehicle deck above the azimuth thruster, there is a problem that the available vehicle mounting space on the vehicle deck may be reduced.
The present disclosure has been made to solve the above-mentioned problems, and aims to provide a vessel that can expand the usable space inside the hull.

In order to solve the above problems, the following configuration is adopted.
The vessel according to the present disclosure comprises a hull having a deck dividing the interior into a plurality of upper and lower levels, one main propulsion unit provided at the stern of the hull, one rudder provided at the stern side of each of the main propulsion units, and a strut section provided on each side of the main propulsion unit in the width direction of the hull, the strut section being tiltable about a tilting axis extending horizontally and displaceable between a use position extending downward from the stern side bottom of the hull located above the main propeller of the main propulsion unit and a storage position extending along the stern side bottom, the strut section extending downward from the stern side bottom when in the use position, and a support section supported by a lower part of the strut section and rotatable about a rotation axis extending vertically when in the use position. and a secondary propulsion unit supported by the support portion and rotatable about a rotation axis extending in a direction intersecting the pivot axis; a tilting device that raises or lowers the secondary propulsion unit between the use position and the stowed position; a power generating unit that generates power for the secondary propulsion unit; and a power transmission unit that transmits the power generated by the power generating unit to the secondary propulsion unit, and the hull is provided with storage units, one on each side of the main propulsion unit in the ship's width direction at the stern, each having an opening that opens into the stern side bottom, formed so as to be recessed upward from the stern side bottom, and located below the deck immediately above the stern side bottom, for accommodating each of the secondary propulsion units in the stowed position.

The vessel described above allows for increased usable space within the hull.

1 is a perspective view of a stern structure of a marine vessel according to a first embodiment of the present disclosure, viewed from slightly above the stern side. FIG. FIG. 1 is a view of the stern structure as seen from the stern side, showing the auxiliary propulsion unit in an operating position. FIG. 10 is a view of the stern structure as seen from the outside in the ship's width direction, showing the auxiliary propulsion unit in an operating position. FIG. 3 is a view corresponding to FIG. 2 showing the secondary propulsion unit in a stowed position. FIG. 4 is a view corresponding to FIG. 3 showing the secondary propulsion unit in a stowed position. 1 is a diagram schematically illustrating a power transmission device according to a first embodiment of the present disclosure. 1 is a diagram showing the storage section in the first embodiment of the present disclosure as viewed from below, with the lid section open and the auxiliary propulsion unit in the storage position. FIG. FIG. 10 is a view of a stern structure according to a second embodiment of the present disclosure, as viewed from the stern side. FIG. 10 is a view of the stern structure of the second embodiment of the present disclosure as seen from the outer side in the ship width direction.

[First embodiment]
A marine vessel according to a first embodiment of the present disclosure will now be described with reference to the drawings. Fig. 1 is a perspective view of a stern structure of a marine vessel according to a first embodiment of the present disclosure, viewed from slightly above the stern side. Fig. 2 is a view of the stern structure viewed from the stern side, showing the auxiliary propulsion unit in the use position. Fig. 3 is a view of the stern structure viewed from the outside in the ship's width direction, showing the auxiliary propulsion unit in the use position.

(Vessel configuration)
The ship 1 of this embodiment is a ship such as a ferry, a RORO ship, or a car carrier that has a vehicle boarding deck on which vehicles can be driven and boarded.
As shown in Figures 1 to 3, the vessel 1 in this embodiment includes a hull 11, a main propulsion unit 12, an auxiliary propulsion unit 13, a rudder 14, a raising and lowering device 15 (see Figure 2), a power generating unit 16 (see Figure 3), and a power transmission unit 17 (described later).

The hull 11 comprises at least a pair of left and right side walls 21, a ship bottom 22 connecting the side walls 21 below, and a deck 23 dividing the ship into multiple upper and lower levels. The hull 11 of this embodiment also has a shore ramp 25 (see Figure 1) at the stern 11F, which forms a running path between the vehicle boarding deck 24 and the quay. Of the multiple decks 23, the deck 23 that is continuous with the running path of the shore ramp 25 is the vehicle boarding deck 24. The shore ramp 25 is not shown in Figures 2 and 3.

The main propulsion unit 12 is equipped with at least a main propeller 26. The main propeller 26 is attached to the aft end of a propeller shaft 27 (see Figure 3) and is rotatable around a propeller axis 28 extending in the fore-aft direction FA. The propeller shaft 27 is rotated by power from a main engine (not shown). The main engine (not shown) is an internal combustion engine, electric motor, or the like, and is disposed within the hull 11 on the bow side of the main propeller 26 in the fore-aft direction FA. The main propulsion unit 12 of this embodiment has only one main propeller 26, located at the center in the transverse direction W. Furthermore, the main propeller 26 of this embodiment is disposed adjacent to the aft side of the bossing 29, and the aft-side ship bottom 22 (hereinafter referred to as the aft-side ship bottom 30), extending in the fore-aft direction FA and the transverse direction W, is located above this main propeller 26. In this embodiment, the main propeller 26 can be a so-called controllable pitch propeller (CPP), which allows the blade angle to be freely changed.

Figure 4 is a view corresponding to Figure 2 showing the secondary propulsion unit in the stowed position. Figure 5 is a view corresponding to Figure 3 showing the secondary propulsion unit in the stowed position.
The auxiliary propulsion unit 13 includes a strut portion 31, a support portion 32, and an auxiliary propeller 33. The auxiliary propulsion unit 13 in this embodiment is a so-called azimuth thruster. The auxiliary propulsion unit 13 is provided near the stern 11F and is tiltable about a tilting shaft 34 extending horizontally. Specifically, the auxiliary propulsion unit 13 is displaceable between an in-use position (see FIGS. 2 and 3 ) in which it is used and a stowed position (see FIGS. 4 and 5 ) in which it is not used. When in the in-use position, the auxiliary propulsion unit 13 is in an upright position extending downward from the stern-side ship bottom 30 of the hull 11, and when in the stowed position, it is in a reclined position extending along the stern-side ship bottom 30 of the hull 11.

In this embodiment, the tilting shaft 34 extends in the ship's width direction W. The base end 35 of the auxiliary propulsion unit 13 is supported so that it can be raised or lowered around this tilting shaft 34 extending in the ship's width direction W. The tip end 36 of the auxiliary propulsion unit 13 displaces toward the stern 11F in the fore-aft direction FA when displacing from the use position to the stowed position. On the other hand, the tip end 36 of the auxiliary propulsion unit 13 displaces toward the bow in the fore-aft direction FA when displacing from the stowed position to the use position. The trajectory of the tip end 36 of the auxiliary propulsion unit 13 displacing in this manner forms an arc that gradually increases upward as it moves from the use position toward the stern 11F; in other words, it gradually increases toward the bow as it moves downward from the stowed position.

The strut section 31 is formed to extend downward from the stern side of the ship's bottom 30 when the auxiliary propulsion unit 13 is in the operating position. The strut section 31 is formed integrally with the base end 35, and is located in the area from the stern side of the ship's bottom 30 to the support section 32 when in the operating position. The support section 32 is supported at the bottom of the strut section 31. A drive shaft (not shown) for transmitting power to the auxiliary propeller 33 and a mechanism (not shown) for rotating the support section 32 are provided inside the strut section 31.

In this embodiment, the strut section 31 is formed with an airfoil-shaped or spindle-shaped cross section, with the dimension in the ship's width direction W gradually decreasing toward the stern 11F to reduce appendage resistance during navigation. The length dimension in the vertical direction H of the strut section 31 may be, for example, a dimension such that the distance from the water surface to the center of the auxiliary propeller 33 (described later) is equal to or greater than the diameter of the auxiliary propeller 33. Furthermore, the length dimension in the vertical direction H of the strut section 31 may be a dimension such that the center of the auxiliary propeller 33 (described later) is located above the center of the main propeller 26. This prevents air bubbles from being drawn in from the water surface by the auxiliary propeller 33 and also prevents the strut section 31 from being too long, resulting in insufficient strength, or becoming excessively heavy. In this embodiment, the dimension in the fore-aft direction FA of the strut section 31 is smaller than the dimension in the fore-aft direction FA of the support section 32 when the auxiliary propeller 33 is oriented in the fore-aft direction FA.

When in the use position, the support part 32 is rotatable around a pivot 37 extending in the vertical direction H. This support part 32 rotatably supports the auxiliary propeller 33. In this embodiment, the support part 32 is rotatable around the pivot 37, in other words, it can rotate at least 360 degrees.

The auxiliary propeller 33 is supported by the support portion 32. The auxiliary propeller 33 is rotatable about a rotation axis 38 that extends in a direction intersecting the rotation axis 37. In this embodiment, the auxiliary propeller 33 is rotatable about the rotation axis 38 that is perpendicular to the rotation axis 37. Power from the power generating unit 16 is transmitted to the auxiliary propeller 33 via a shaft (not shown) or the like provided within the auxiliary propulsion unit 13. By rotating the support portion 32 about the rotation axis 37, the thrust of the auxiliary propeller 33 can be exerted radially outward around the rotation axis 37 over the entire circumferential direction around the rotation axis 37.

The vessel 1 of this embodiment is provided with two auxiliary propulsion units 13. These two auxiliary propulsion units 13 are provided one on each of the port and starboard sides of the main propulsion unit 12, which are located further outward in the ship's width direction W than the main propulsion unit 12. In this embodiment, the two auxiliary propulsion units 13 are arranged symmetrically with respect to the center position in the ship's width direction W.

The rudder 14 is provided on the stern 11F side of the main propulsion unit 12. The rudder 14 illustrated in this embodiment is a so-called suspended rudder, and its angle can be changed around a rudder shaft 39 extending in the vertical direction H. The rudder 14 in this embodiment is located immediately behind the main propeller 26 of the main propulsion unit 12, and changes the direction of the water current generated by the main propeller 26, thereby changing the direction of the hull 11. In this embodiment, one rudder 14 is provided, and this one rudder 14 is provided immediately behind the main propeller 26. Note that the rudder 14 is not limited to a suspended rudder.

Here, the auxiliary propulsion device 13 is positioned so as not to overlap the rudder 14 in the fore-and-aft direction FA when the auxiliary propulsion device 13 is in the use position and the rotation shaft 38 of the auxiliary propeller 33 faces in the ship's transverse direction W. Furthermore, the auxiliary propulsion device 13 is positioned so as not to overlap the main propeller 26 in the fore-and-aft direction FA when the auxiliary propulsion device 13 is in the use position and the rotation shaft 38 of the auxiliary propeller 33 faces in the ship's transverse direction W. In this embodiment, the auxiliary propulsion device 13 is positioned between the rudder 14 and the main propeller 26 in the fore-and-aft direction FA when the auxiliary propulsion device 13 is in the use position and the rotation shaft 38 of the auxiliary propeller 33 extends in the ship's transverse direction W. In Figure 3, the tip trajectory of the auxiliary propeller 33 when the auxiliary propulsion device 13 is in the use position and the rotation shaft 38 of the auxiliary propeller 33 faces in the ship's transverse direction W is indicated by a two-dot chain circle.

The raising/lowering device 15 raises/lowers the secondary propulsion unit 13 between the use position and the stowed position. Specifically, the raising/lowering device 15 is capable of rotating the base end 35 of the secondary propulsion unit 13 around the raising/lowering axis 34. An example of a configuration for rotating the base end 35 of the secondary propulsion unit 13 around the raising/lowering axis 34 is to provide a hydraulic motor or hydraulic cylinder as a power source, and use the hydraulic motor or hydraulic cylinder to rotate a gear (not shown) connected to the base end 35.

The power generating unit 16 generates power for the auxiliary propulsion unit 13. Specifically, it generates power to rotate the auxiliary propeller 33. In this embodiment, the power generating unit 16 is an electric motor that converts electrical energy into rotational energy. Electricity is supplied to this power generating unit 16 from a generator and a storage battery (neither of which are shown) installed within the hull 11.

FIG. 6 is a diagram schematically illustrating a power transmission device according to the first embodiment of the present disclosure.
The power transmission device 17 transmits power generated by the power generating device 16 to the auxiliary propulsion device 13. As shown in Figure 6, the power transmission device 17 in this embodiment includes a first bevel gear 41 fixed to the tip of a rotor shaft 40 extending horizontally, and a second bevel gear 42 that can mesh with the first bevel gear 41. The first bevel gear 41 and the second bevel gear 42 enable rotation about a first axis 43 extending horizontally to be converted into rotation about a second axis 44 extending in the up-down direction H. The second bevel gear 42 is fixed to a base end 45 of a shaft that extends within the auxiliary propulsion device 13, and the second bevel gear 42 meshes with the first bevel gear 41 when the auxiliary propulsion device 13 is in the use position. That is, the power transmission device 17 of this embodiment transmits power from the power generating device 16 to the secondary propulsion device 13 only when it is in the use position, and otherwise the second bevel gear 42 moves away from the first bevel gear 41 in the direction shown by the arrow in Figure 6 and does not transmit power from the power generating device 16 to the secondary propulsion device 13. Note that the power transmission device 17 is not limited to the above configuration as long as it is capable of transmitting rotational energy of the power generating device 16 about the first axis 43 to the secondary propulsion device 13.

As shown in Figures 4 and 5, the hull 11 has a storage section 46 (also referred to as an intra-hull recess) that accommodates the secondary propulsion unit 13 in the stowed position. The storage section 46 has an opening that opens to the stern-side bottom 30. The storage section 46 is recessed upward from the stern-side bottom 30 and is located below the vehicle loading deck 48 (which may also be the vehicle boarding deck 24) directly above it. In this embodiment, the storage section 46 has side wall sections 49 that extend in the vertical direction H and the fore-aft direction FA to define both sides in the width direction W of the ship; a rear wall section 50 that extends in the vertical direction H and the width direction W to define the stern 11F side; a front wall section 51 that extends in the vertical direction H and the width direction W to define the bow side; and an upper wall section 52 that is formed along the vehicle loading deck 48 directly above and defines the upper side in the vertical direction H.

As shown in Figures 4 and 5, the storage section 46 of this embodiment further has a lid 53 that can open and close the opening 47. This lid 53 is in an open state when the secondary propulsion unit 13 is in the use position, and is in a closed state when the secondary propulsion unit 13 is in the stowed position. The lid 53 opens and closes the opening 47 by sliding, for example, in the bow-stern direction FA or the width direction W by an actuator (not shown). Figure 2 illustrates a case where the lid 53 slides inward in the width direction W when changing from the closed state to the open state.

FIG. 7 is a view of the storage unit in the first embodiment of the present disclosure as seen from below, showing a state in which the lid is open and the secondary propulsion unit is in the storage position.
7, the storage section 46 of the present embodiment includes a first storage section 54 that stores the auxiliary propeller 33 of the auxiliary propulsion unit 13 in the stored position, and a second storage section 55 that stores a portion of the auxiliary propeller 33 closer to the base end 35. The first storage section 54 is formed on the stern 11F side of the second storage section 55.

In this embodiment, the auxiliary propulsion unit 13 is stored in the storage section 46 in a position where the rotation shaft 38 of the auxiliary propeller 33 extends in the vertical direction H and the auxiliary propeller 33 is positioned below the support section 32 (see FIG. 5). The above-mentioned raising and lowering shaft 34 is located within the second storage section 55. In this embodiment, the dimension of the second storage section 55 in the transverse direction W is smaller than the dimension of the first storage section 54 in the transverse direction W. In other words, the storage section 46 is formed to have a size corresponding to the dimension of the auxiliary propulsion unit 13 in the transverse direction W when in the stored position. Also, as shown in FIG. 5, the storage section 46 in this embodiment is formed to be larger than the dimension of the auxiliary propulsion unit 13 in the vertical direction H when in the stored position, so that the auxiliary propulsion unit 13 when in the stored position does not protrude downward from the opening 47.

As shown in Figures 3 and 5, the power generating unit 16 is located on the same floor as the storage unit 46 among the multiple floors within the hull 11. The power generating unit 16 of this embodiment is located adjacent to the storage unit 46 on the bow side, opposite the stern 11F in the fore-aft direction FA. The longitudinal direction of the power generating unit 16 of this embodiment is the direction in which the first axis 43 (see Figure 6) extends, i.e., the direction in which the rotor shaft 40 (see Figure 6) extends. In other words, the external dimensions of the power generating unit 16 in a direction perpendicular to the first axis 43 are smaller than the dimensions in the direction in which the first axis 43 extends. The power generating unit 16 of this embodiment is installed on the same floor as the storage unit 46 with the first axis 43 extending in the fore-aft direction FA.

In addition, as shown in Figure 2, in this embodiment, the raising and lowering devices 15 are also installed on the same floor as the two storage sections 46. In this embodiment, the raising and lowering devices 15 are installed adjacent to each of the two storage sections 46 on the inside in the ship's width direction W.

(Action and effect)
According to the first embodiment of the ship, the auxiliary propulsion unit 13 is capable of being raised and lowered around a horizontally extending raising and lowering axis 34, and is displaceable between a use position extending downward from the stern side bottom 30 of the hull 11 and a storage position extending along the stern side bottom 30 of the hull 11, and the raising and lowering device 15 raises and lowers the auxiliary propulsion unit 13 between the use position and the storage position.
As a result, when the auxiliary propulsion unit 13 is not in use, it is possible to reduce the appendage resistance of the hull 11 by displacing the auxiliary propulsion unit 13 about the raising and lowering axis 34 from the use position to the stowed position. Also, because the auxiliary propulsion unit 13, which extends downward from the stern side ship bottom 30 when in the use position, can be displaced to a stowed position extending along the stern side ship bottom 30, it is possible to reduce the dimension in the up-down direction H of the auxiliary propulsion unit 13 when in the stowed position compared to when the auxiliary propulsion unit 13 is raised and lowered to be stored within the hull 11.
Therefore, even if the auxiliary propulsion unit 13 has struts 31 extending downward from the stern bottom 30 when in the use position, a long vertical space is not required to accommodate the auxiliary propulsion unit 13 within the hull 11 above the auxiliary propulsion unit 13, making it possible to expand the available space within the hull 11. In particular, if a vehicle mounting deck 48 is provided above the auxiliary propulsion unit 13, it is possible to prevent a reduction in vehicle mounting space.
Furthermore, in the event of a failure of the main propulsion unit 12, navigation using the secondary propulsion unit 13 is also possible, thereby ensuring redundancy.

According to the watercraft 1 of the first embodiment, the hull 11 further includes a storage section 46 having an opening 47 that opens to the stern side of the ship bottom 30. The auxiliary propulsion unit 13 in the stored position is stored in this storage section 46.
This prevents the auxiliary propulsion unit 13 in the stowed position from protruding below the stern side of the ship bottom 30, thereby further reducing the additional object resistance of the hull 11.

According to the watercraft 1 of the first embodiment, the storage section 46 further includes the lid section 53 that can open and close the opening section 47 .
This prevents the water flow along the stern side bottom 30 from entering the storage section 46 when the auxiliary propulsion unit 13 is in the storage position and the hull 11 is moving forward and backward or turning, thereby reducing the resistance generated on the stern side bottom 30 of the hull 11.

According to the vessel 1 of the first embodiment, the auxiliary propulsion unit 13 further comprises a support portion 32 and an auxiliary propeller 33, and the support portion 32 is rotatable around a rotation axis 37 extending in the vertical direction H when in the use position, and the auxiliary propeller 33 is supported by the support portion 32 and is rotatable around a rotation axis 38 extending in a direction intersecting the rotation axis 37.
This allows a water flow to be generated in the radial direction around the turning axis 37. Therefore, the auxiliary propulsion device 13 can be used not only for propulsion assistance but also as a stem thruster, which improves maneuverability in harbors and also reduces the number of parts by eliminating the stem thruster. Furthermore, compared to a typical stem thruster, a turning moment lever, which is the distance from the center of the hull 11 in the bow-stern direction FA, can be secured, thereby improving maneuverability in harbors.

According to the ship 1 of the first embodiment, the deck 23 further divides the interior of the hull 11 into a plurality of upper and lower levels, and the power generating unit 16 that generates power for the auxiliary propulsion unit 13 is provided on the same level as the accommodation unit 46. In addition, the ship 1 is provided with a power transmission unit 17 that transmits the power generated by the power generating unit 16 to the auxiliary propulsion unit 13.
This makes it possible to prevent the space on the floor immediately above the storage section 46 from being reduced, compared to when the power generating device 16 is disposed above the storage section 46 .

The ship of the first embodiment described above further includes one main propulsion unit 12, one rudder 14 provided on the stern side of the main propulsion unit 12, and two auxiliary propulsion units 13 provided on both sides of the main propulsion unit 12 in the ship's width direction W.
This allows a so-called one-engine, one-shaft, one-rudder vessel to provide propulsion assistance using two auxiliary propulsion units 13, and also makes it possible to secure space for arranging two retractable auxiliary propulsion units 13.

According to the ship of the first embodiment described above, furthermore, the auxiliary propulsion unit 13 is provided in a position where it does not overlap with the rudder 14 in the fore-aft direction FA when it is in the use position and the rotation axis extends in the ship's width direction W, and is provided in a position where it does not overlap with the main propeller 26 of the main propulsion unit 12 in the fore-aft direction FA.
This makes it possible to prevent the water flow generated by the auxiliary propeller 33 from interfering with the rudder 14 or the main propeller 26 when the support part 32 of the auxiliary propulsion unit 13 is rotated and the direction of the water flow generated by the auxiliary propeller 33 is set in the ship's width direction W.

[Modification of the first embodiment]
In the first embodiment described above, the power generating unit 16 is disposed adjacent to the housing portion 46. However, the power generating unit 16 is not limited to being disposed inside the hull 11. For example, the auxiliary propulsion unit 13 may be a so-called pod propulsion unit that includes an electric motor, which serves as a power generating unit, inside the support portion 32.
By doing so, there is no need to secure space for arranging the power generating device 16 within the hull 11, and the space within the hull 11 can be used effectively.

[Second embodiment]
Next, a second embodiment of the present disclosure will be described with reference to the drawings. This second embodiment differs from the first embodiment in that the orientation of the raising and lowering shaft 34 of the auxiliary propulsion device 13 is different. Therefore, the same parts as those in the first embodiment will be denoted by the same reference numerals and will not be described again.

Fig. 8 is a view of the stern structure of the second embodiment of the present disclosure as seen from the stern side. Fig. 9 is a view of the stern structure of the second embodiment of the present disclosure as seen from the outer side in the width direction of the ship.
The ship 101 of the second embodiment, like the first embodiment, is equipped with a hull 11, a main propulsion unit 12, a secondary propulsion unit 113, a rudder 14, a raising and lowering device 15, a power generating unit 116, and a power transmission unit 17.

As shown in Figures 8 and 9, the auxiliary propulsion unit 113 in the second embodiment includes a support portion 32 and an auxiliary propeller 33. Like the auxiliary propulsion unit 13 in the first embodiment, the auxiliary propulsion unit 113 in this embodiment is a so-called azimuth thruster. The auxiliary propulsion unit 113 is mounted on the stern 11F and is retractable about a horizontally extending retractable shaft 34. Specifically, the auxiliary propulsion unit 113 moves between an in-use position, in which it is in use, and a stowed position, in which it is not in use. When in the in-use position, the auxiliary propulsion unit 113 is in an upright position, extending downward from the stern-side bottom 30 of the hull 11. When in the stowed position, the auxiliary propulsion unit 113 is in a retracted position, extending along the stern-side bottom 30 of the hull 11. Note that the base end of the auxiliary propulsion unit 113 is not shown in Figure 8.

The tilting shaft 34 of this embodiment extends in the ship's width direction W, similar to the tilting shaft 34 of the first embodiment. The base end of the auxiliary propulsion unit 113 is supported so as to be able to tilt about this tilting shaft 34 extending in the ship's width direction W. The auxiliary propulsion unit 113 of the second embodiment is configured to tilt in the opposite direction in the fore-aft direction FA to that of the auxiliary propulsion unit 13 of the first embodiment. Specifically, the tip end 36 of the auxiliary propulsion unit 113 displaces toward the bow in the fore-aft direction FA when displacing from the use position to the stowed position, while the tip end 36 of the auxiliary propulsion unit 113 displaces toward the stern 11F in the fore-aft direction FA when displacing from the stowed position to the use position. The trajectory of the tip end 36 of the auxiliary propulsion unit 113 displacing in this manner forms an arc that gradually moves upward as it moves from the use position toward the bow. In other words, it gradually moves downward as it moves toward the stern 11F as it moves downward from the stowed position. Like the vessel 1 of the first embodiment, the vessel 101 of this second embodiment also has two auxiliary propulsion units 113, one on each of the port and starboard sides of the main propulsion unit 12, which are located further outboard in the ship's width direction W than the main propulsion unit 12.

The hull 11 is equipped with a storage section 46 that stores the secondary propulsion unit 113 in the stowed position. The storage section 46 of this second embodiment is located slightly closer to the stern 11F than the storage section 46 of the first embodiment. The storage section 46 has an opening 47 that opens into the stern side bottom 30 and is formed so as to be recessed upward from the stern side bottom 30. As with the first embodiment, the storage section 46 of the second embodiment is formed on the level directly below the vehicle loading deck 48. Here, the storage section 46 may be located on the level directly below the vehicle boarding deck 24 rather than on the level directly below the vehicle loading deck 48.

The storage compartment 46 includes a first storage compartment 54 that stores the secondary propeller 33 of the secondary propulsion unit 113 when it is in the stowed position, and a second storage compartment 55 that stores the portion of the secondary propeller 33 closer to the base end. The first storage compartment 54 is located on the bow side of the second storage compartment 55. In other words, the storage compartment 46 of the second embodiment has the first storage compartment 54 and the second storage compartment 55 arranged in the bow-stern direction FA opposite to the storage compartment 46 of the first embodiment. In this second embodiment, the secondary propulsion unit 113 is stored in the storage compartment 46 with the rotation shaft 38 of the secondary propeller 33 extending in the vertical direction H and the secondary propeller 33 positioned above the support portion 32. The storage compartment 46 of the second embodiment is also sized so that the secondary propulsion unit 113 when in the stowed position does not protrude downward from the opening 47.

In this embodiment, one tilting device 15 is installed adjacent to each of the two storage sections 46 on the outer side in the ship's width direction W. The tilting device 15 tilts the secondary propulsion unit 113 between the use position and the storage position. Specifically, the tilting device 15 is capable of rotating the base end of the secondary propulsion unit 113 around the tilting shaft 34. Note that the placement of the tilting device 15 is not limited to the above placement, and it may also be placed, for example, on the bow side of the power generating unit 116.

The power generating unit 116 is located on the same level as the storage unit 46 among the multiple levels within the hull 11. In this embodiment, the power generating unit 116 is located adjacent to the storage unit 46 on the inside in the ship's width direction W (in other words, toward the center in the ship's width direction W). In this embodiment, the power generating unit 116 has the longitudinal direction along the first axis 43, and is formed so that the dimension perpendicular to the first axis 43 is smaller than the dimension in the direction along the first axis 43. The power generating unit 116 in this embodiment is installed on the same level as the storage unit 46 with the first axis 43 extending in the ship's width direction W.

The power transmission device 17 transmits the power generated by the power generation device 16 to the secondary propulsion device 113. The power transmission device 17 differs from the power transmission device 17 of the first embodiment only in its arrangement. As with the first embodiment, the power transmission device 17 can also be configured, for example, to include a first bevel gear 41 and a second bevel gear 42. Note that the power transmission device 17 is not shown in Figures 8 and 9.

When the auxiliary propulsion device 113 is in the use position and the rotation shaft 38 of the auxiliary propeller 33 faces in the ship's width direction W, the auxiliary propulsion device 113 is positioned so as not to overlap with the rudder 14 in the fore-aft direction FA. In the second embodiment, the auxiliary propulsion device 113 is positioned closer to the stern 11F than the rudder 14 in the fore-aft direction FA, so when the auxiliary propulsion device 113 is in the use position and the rotation shaft 38 of the auxiliary propeller 33 faces in the ship's width direction W, it is positioned so as not to overlap with the main propeller 26 in the fore-aft direction FA. In Figure 9, the tip trajectory of the auxiliary propeller 33 when the auxiliary propulsion device 113 is in the use position and the rotation shaft 38 of the auxiliary propeller 33 extends in the ship's width direction W is indicated by a two-dot chain circle.

(Action and effect)
According to the ship 101 of the second embodiment, in addition to the effects of the first embodiment, the power generating unit 116 can be disposed inside the storage section 46 in the ship's width direction W, which makes it possible to install a retractable auxiliary propulsion unit 113 even in cases where space cannot be secured to install the power generating unit 116 on the bow side of the storage section 46. Furthermore, when in the use position, the auxiliary propeller 33 can be disposed closer to the stern 11F than the auxiliary propeller 33 of the first embodiment, which makes it possible to increase the turning moment lever, which is the distance from the center of the hull 11 in the fore-aft direction FA, and thereby improves ship maneuverability in a harbor.

Other Embodiments
The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.
For example, in each of the above embodiments, the case where the sub-propeller 33 is rotated in the use position to generate a water current has been described. However, the sub-propeller 33 does not have to be rotated in the use position. For example, the sub-propeller 33 may be rotated in a position between the use position and the stowed position, as long as the entire sub-propeller 33 is positioned below the opening 47 of the stowed portion 46. In this way, the sub-propeller 33 can be rotated near the water surface, which can prevent the sub-propeller 33 from interfering with obstacles when the draft is shallow, for example.

In each of the above embodiments, one auxiliary propulsion device 13, 113 is provided with one auxiliary propeller 33, but one auxiliary propulsion device 13, 113 may be provided with a plurality of auxiliary propellers 33.
In the above embodiments, the raising/tilting shaft 34 extends in the ship's width direction W, which is a horizontal direction perpendicular to the fore-and-aft direction FA. However, the raising/tilting shaft 34 may extend in any direction as long as the auxiliary propulsion unit 13, 113 can be raised or lowered between the use position and the stowed position. Furthermore, the shape of the storage section 46 may be any shape as long as it can accommodate the auxiliary propulsion unit 13, 113 in the stowed position. That is, in the above embodiments, the first storage section 54 and the second storage section 55 have different dimensions in the ship's width direction W. However, for example, the storage section 46 may have a rectangular opening 47.

In the above embodiments, an example has been described in which the storage section 46 is provided with a lid section 53 that can open and close the opening 47. However, the lid section 53 may be provided as needed, and for example, the lid section 53 may not be provided. Furthermore, the sliding direction of the lid section 53 is not limited to the ship's width direction W, and may be, for example, the fore-and-aft direction FA.

The auxiliary propulsion device 13 , 113 in each of the above embodiments may further include a cylindrical nozzle surrounding the periphery of the auxiliary propeller 33 .
In each of the above embodiments, a case has been described in which the auxiliary propulsion unit 13, 113 in the stowed position does not protrude downward below the opening 47 of the storage section 46, but the auxiliary propulsion unit 13, 113 in the stowed position may protrude downward below the opening 47 of the storage section 46, i.e., below the stern-side ship bottom 30. Furthermore, in each of the embodiments, a case has been described in which the storage section 46 is provided, but a retractable auxiliary propulsion unit 13 may also be provided in a hull 11 that does not have a storage section 46.

<Additional Notes>
The vessel 1 described in the embodiment can be understood, for example, as follows.

(1) According to the first aspect, the vessel 1, 101 comprises a hull 11, a main propulsion unit 12 provided at the stern of the hull 11, and a main propulsion unit 12 provided at the stern and capable of being raised or lowered around a horizontally extending raising or lowering shaft 34. The main propulsion unit 12 is displaceable between a use position extending downward from the stern side bottom 30 of the hull 11 and a storage position extending along the stern side bottom 30 of the hull 11. When the main propulsion unit 12 is in the use position, the main propulsion unit 12 is displaceable between a use position extending downward from the stern side bottom 30 of the hull 11 and a storage position extending along the stern side bottom 30 of the hull 11. and an auxiliary propulsion unit (13, 113) having a strut portion (31), a support portion (32) that is supported by the lower portion of the strut portion (31) when in the use position and is rotatable around a rotation axis (37) extending in the vertical direction (H), and an auxiliary propeller (33) that is supported by the support portion (32) and is rotatable around a rotation axis (38) extending in a direction intersecting with the rotation axis (37); and an elevation device (15) that raises or lowers the auxiliary propulsion unit (13, 113) between the use position and the storage position.
Examples of the vessel 1, 101 include a ferry, a RORO ship, and a car carrier. Examples of the secondary propulsion device 13, 113 include an azimuth thruster and a pod thruster.

As a result, when the auxiliary propulsion device 13, 113 is not in use, it is possible to reduce the appendage resistance of the hull 11 by displacing the auxiliary propulsion device 13, 113 about the raising and lowering shaft 34 from the use position to the stowed position. Furthermore, because the auxiliary propulsion device 13, 113, which extends downward from the stern side ship bottom 30 when in the use position, can be displaced to a stowed position extending along the stern side ship bottom 30, the vertical dimension H of the auxiliary propulsion device 13, 113 in the stowed position can be reduced compared to when the auxiliary propulsion device 13, 113 is raised and lowered to be stored within the hull 11. Furthermore, because the strut portion 31 extends downward from the stern side ship bottom 30 when in the use position, it is possible to reduce the vertical dimension H of the auxiliary propulsion device 13, 113 in the stowed position even if the vertical dimension H of the auxiliary propulsion device 13, 113 is large.
Therefore, a long vertical space for accommodating the secondary propulsion units 13, 113 within the hull 11 above the secondary propulsion units 13, 113 is not required, and it is possible to expand the available space within the hull 11. In particular, if a vehicle mounting deck is provided above the secondary propulsion units 13, 113, it is possible to prevent a reduction in the vehicle mounting space.

Furthermore, a water flow can be generated in the radial direction centered on the rotation axis 37. Therefore, the auxiliary propulsion unit 13 can be used not only for propulsion assistance but also as a stern thruster, which improves maneuverability within a harbor and also reduces the number of parts by eliminating the stern thruster. Furthermore, compared to a typical stern thruster, a turning moment lever, which is the distance from the center of the hull 11 in the bow-stern direction FA, can be secured, thereby improving maneuverability within a harbor.

(2) The vessel 1, 101 according to the second aspect is the vessel 1, 101 of (1), in which the hull 11 is provided with a storage section 46 having an opening that opens into the stern side bottom 30, and the storage section 46 stores the secondary propulsion unit 13 in the storage position.
This prevents the auxiliary propulsion units 13, 113 in the stowed position from protruding downward from the stern side of the ship bottom 30, thereby further reducing the additional object resistance of the hull 11.

(3) The vessel 1, 101 according to a third aspect is the vessel 1, 101 of (2), in which the storage section 46 includes a lid section that can open and close the opening.
This prevents the water flow along the stern side bottom 30 from entering the storage section 46 when the auxiliary propulsion unit 13 is in the storage position and the hull 11 is moving forward and backward or turning, thereby reducing the resistance generated on the stern side bottom 30 of the hull 11.

(4) The ship 1,101 according to the fourth aspect is the ship 1,101 of (2) or (3), and has a deck that divides the interior of the hull 11 into multiple upper and lower levels, and is equipped with a power generating unit 16,116 that is provided on the same level as the storage section 46 and generates power for the secondary propulsion unit 13, and a power transmission unit 17 that transmits the power generated by the power generating unit 16,116 to the secondary propulsion unit 13,113.
This makes it possible to prevent the space above the accommodation section 46 from being reduced compared to when the power generating device 16, 116 is disposed above the accommodation section 46.

(5) The vessel 1, 101 according to the fifth aspect is any one of the vessels 1, 101 of (1) to (4), in which the auxiliary propulsion unit 13, 113 is arranged in a position that does not overlap with the rudder 14 in the fore-aft direction FA when the auxiliary propulsion unit 13, 113 is in the use position and the rotating shaft 38 extends in the ship's width direction W, and is arranged in a position that does not overlap with the main propeller 26 of the main propulsion unit 12 in the fore-aft direction FA.
This makes it possible to prevent the water flow generated by the auxiliary propeller 33 from interfering with the rudder 14 or the main propeller 26 when the support part 32 of the auxiliary propulsion unit 13, 113 is rotated and the direction of the water flow generated by the auxiliary propeller 33 is set to the ship's width direction W.

(6) The vessel 1, 101 according to the sixth aspect is any one of the vessels 1, 101 of (1) to (4), in which the auxiliary propulsion device 13 is equipped with a power generating device that generates power inside the support portion 32.
This eliminates the need to secure space for arranging the power generating devices 16, 116 within the hull 11, allowing the space within the hull 11 to be used effectively.

(7) The vessel 1, 101 according to the seventh aspect is any one of the vessels 1, 101 of (1) to (6), and is equipped with one main propulsion unit 12, one rudder 14 provided on the stern 11F side of one of the main propulsion units 12, and two secondary propulsion units 13, 113 provided on each side of the main propulsion unit 12 in the ship's width direction W.
This allows the so-called one-engine, one-shaft, one-rudder vessel 1, 101 to provide propulsion assistance using two auxiliary propulsion units 13, 113, and also makes it possible to secure space for arranging two retractable auxiliary propulsion units 13, 113.

1,101...Vessel 11...Hull 11F...Stern 12...Main propulsion unit 13,113...Secondary propulsion unit 14...Rudder 15...Raising/tilting device 16,116...Power generating unit 17...Power transmission unit 21...Side 22...Bottom 23...Deck 24...Vehicle boarding deck 25...Shore ramp 26...Main propeller 27...Propeller shaft 28...Propeller axis 29...Bossing 30...Stern side of bottom 31...Strut section 31 32...Support section 33...Secondary propeller 34...Raising/tilting shaft 35...Base end 36...Tip end 37...Swivel shaft 38...Rotation shaft 39...Rudder stock 40...Rotor shaft 41...First bevel gear 42...Second bevel gear 43...First axis 44...Second axis 45: Base end 46: Storage section 47: Opening 48: Vehicle loading deck 49: Side wall 50: Rear wall 51: Front wall 52: Upper wall 53: Lid 54: First storage section 55: Second storage section

Claims (5)

A hull with a deck that divides the interior into multiple upper and lower levels,
one main propulsion unit mounted at the stern of the hull;
a rudder provided on the stern side of one of the main propulsion units;
two auxiliary propulsion units, each provided on either side of the main propulsion unit in the width direction at the stern, each of which is raiseable and reclining about a horizontally extending raising axis and which is displaceable between a use position extending downward from the stern side bottom of the hull located above the main propeller of the main propulsion unit and a storage position extending along the stern side bottom, each of which has a strut section extending downward from the stern side bottom when in the use position, a support section supported by a lower part of the strut section when in the use position and capable of rotating about a vertically extending rotation axis, and an auxiliary propeller supported by the support section and rotatable about a rotation axis extending in a direction intersecting the rotation axis;
an elevation device that raises or lowers the auxiliary propulsion unit between the use position and the storage position;
a power generating device that generates power for the secondary propulsion device;
a power transmission device that transmits the power generated by the power generating device to the secondary propulsion device;
Equipped with
The hull is
A ship having storage sections, each of which is provided on either side of the main propulsion unit in the stern in the ship's width direction, each of which has an opening that opens into the stern side bottom of the ship, each of which is formed to be recessed upward from the stern side bottom of the ship, and which are located below the deck immediately above the stern side bottom of the ship, and which each store the auxiliary propulsion units in the storage position. The watercraft according to claim 1 , wherein the storage section includes a lid that can open and close the opening. 3. The ship according to claim 1, wherein the auxiliary propulsion device is provided at a position not overlapping with a rudder in the bow-stern direction when the auxiliary propulsion device is in the use position and the rotation shaft extends in the ship's width direction, and is provided at a position not overlapping with a main propeller of the main propulsion device in the bow-stern direction. The watercraft according to any one of claims 1 to 3, wherein the auxiliary propulsion device includes a power generating device that generates power inside the support portion. the power generating device is provided on the same floor as the accommodation unit among a plurality of floors within the hull,
The watercraft according to any one of claims 1 to 3, wherein the longitudinal direction of the power generating device is the direction in which a rotor shaft of the power generating device extends and is also horizontal.