Ship propulsion device and ship

Abstract

To provide a vessel propulsion device and a vessel capable of improving propulsion performance.SOLUTION: A vessel propulsion device includes: a plurality of ducts provided on a bottom of a hull and lined up in width direction crossing a front-rear direction of the hull; propellers arranged rotatably inside respective ducts and generating a flow in the front-rear direction inside the ducts; and a fairing material provided on at least one of a front side or a back side between the ducts, respectively continued with inner surfaces of ducts adjacent to each other, and having a pair of guide surfaces projecting in the front-rear direction from the ducts. A dimension of the fairing material in the width direction becomes smaller as it separates from the ducts in the front-rear direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a vessel propulsion device and a vessel. [Background technology]

[0002] Patent Document 1 discloses a vessel propulsion device having a rotor (propeller) with multiple blades. The propeller is rotatably arranged within a nozzle (duct). This propeller improves propulsion performance by recovering the flow of the boundary layer that occurs at the bottom of the ship on the stern side while the ship is sailing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2013-503784 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when multiple marine propulsion devices with propellers in ducts are arranged side by side at the stern, gaps may form between the ducts, which increases resistance and reduces propulsion performance.

[0005] The present disclosure has been made to solve the above-described problems, and has an object to provide a vessel propulsion device and a vessel that can improve propulsion performance. [Means for solving the problem]

[0006] In order to solve the above problems, a marine vessel propulsion device according to the present disclosure includes a plurality of ducts provided on the bottom of a hull and aligned in a width direction intersecting the fore-and-aft direction of the hull, a propeller rotatably disposed inside each of the ducts and generating a flow in the fore-and-aft direction within the duct, and a fairing material provided on at least one of the front and rear sides between the ducts and having a pair of guide surfaces that are continuous with the inner surfaces of adjacent ducts and protrude from the ducts in the fore-and-aft direction, wherein the dimension of the fairing material in the width direction decreases as the distance from the duct in the fore-and-aft direction increases. The lower surface of the outer surface of the duct extends in the fore-and-aft direction while curving so as to protrude downward at a middle portion in the fore-and-aft direction, and the lower surface of the fairing material is smoothly connected to the lower surface of the outer surface of the duct. . In addition, the marine vessel propulsion device according to the present disclosure comprises a plurality of ducts provided on the bottom of a hull and arranged in a width direction intersecting the fore-and-aft direction of the hull; a propeller rotatably arranged inside each of the ducts and generating a flow in the fore-and-aft direction within the duct; and fairing material provided on at least one of the front and rear sides between the ducts, the fairing material having a pair of guide surfaces that are continuous with the inner surfaces of adjacent ducts and protrude from the ducts in the fore-and-aft direction, the width dimension of the fairing material decreasing as it moves away from the duct in the fore-and-aft direction, and the fairing material is provided between ducts of different sizes.

[0007] A vessel according to the present disclosure includes the vessel propulsion device described above and the hull. [Effects of the Invention]

[0008] According to the vessel propulsion device and vessel of the present disclosure, it is possible to improve propulsion performance. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a marine vessel according to a first embodiment of the present disclosure, viewed from the width direction. [Figure 2] 1 is a schematic diagram of a vessel propulsion device according to a first embodiment of the present disclosure, as viewed from the rear side. FIG. [Figure 3] FIG. 2 is a schematic diagram of a duct and a fairing material according to the first embodiment of the present disclosure, viewed from the width direction. [Figure 4] FIG. 2 is a schematic diagram showing two adjacent ducts and a fairing material provided between the ducts, as viewed from below, according to the first embodiment of the present disclosure. [Figure 5] FIG. 10 is a schematic diagram showing two adjacent ducts and a fairing material provided between these ducts, as viewed from below, according to a modified example of the first embodiment of the present disclosure. [Figure 6] FIG. 10 is a schematic diagram of a duct and a fairing material according to a second embodiment of the present disclosure, viewed from the width direction. [Figure 7] FIG. 10 is a schematic diagram showing two adjacent ducts and a fairing material provided between the ducts, as viewed from below, according to a second embodiment of the present disclosure. [Figure 8] FIG. 10 is a schematic diagram of a duct and a fairing material according to a third embodiment of the present disclosure, viewed from the rear side. [Figure 9] FIG. 10 is a schematic diagram of a duct and a fairing material according to a third embodiment of the present disclosure, viewed from the width direction. [Figure 10] FIG. 10 is a schematic diagram showing two adjacent ducts and a fairing material provided between the ducts, as viewed from below, according to a third embodiment of the present disclosure. [Figure 11] FIG. 10 is a schematic diagram of a duct and a fairing material according to a fourth embodiment of the present disclosure, viewed from the rear side. [Figure 12] FIG. 10 is a schematic diagram showing two adjacent ducts and a fairing material provided between the ducts, as viewed from below, according to a fourth embodiment of the present disclosure. [Figure 13] FIG. 10 is a schematic diagram showing two adjacent ducts and a fairing material provided between these ducts, as viewed from below, according to a first modified example of the fourth embodiment of the present disclosure. [Figure 14] FIG. 10 is a schematic diagram showing two adjacent ducts and a fairing material provided between these ducts, as viewed from below, according to a second modified example of the fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment (ship) A boat 1 and a boat propulsion device 10 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 4. FIG. As shown in FIG. 1, the boat 1 includes a hull 2 ​​and a boat propulsion device 10 .

[0011] (Hull) The hull 2 ​​is a box-shaped structure that floats on water. The hull 2 ​​extends in one direction along a horizontal plane. The hull 2 ​​has a bow 3, a stern 4, and a bottom 5. The bow 3 is the part on one side of the hull 2 ​​in the longitudinal direction. The stern 4 is the part on the other side of the hull 2 ​​in the longitudinal direction.

[0012] Hereinafter, the longitudinal direction of the vessel 1 may be referred to as the fore-and-aft direction D of the vessel 1, or simply as the "fore-and-aft direction D." Furthermore, within the fore-and-aft direction D, the bow 3 side may be referred to as the "forward side Df," and the stern 4 side may be referred to as the "aft side Da." Furthermore, a horizontal direction that intersects with the fore-and-aft direction D may be referred to as the width direction W of the hull 2, or simply as the "width direction W." Furthermore, the vertical up-down direction that intersects with the horizontal plane may be referred to simply as the "up-down direction."

[0013] The bottom 5 forms the lower bottom of the hull 2. The bottom 5 extends in the fore-and-aft direction D and connects the bow 3 and the stern 4. A center skeg 6 is provided on the aft side Da of the bottom 5. The center skeg 6 is located in the center of the width direction W of the bottom 5 (on the center line). The center skeg 6 extends in the fore-and-aft direction D.

[0014] (Ship propulsion system) The vessel propulsion device 10 is installed on the underside of the rear side Da of the vessel bottom 5. As shown in FIG. 2, the underside of the vessel bottom 5 on which the vessel propulsion device 10 is installed is along a horizontal plane. The vessel propulsion devices 10 are installed on both sides in the width direction W, with a center skeg 6 in between. These two vessel propulsion devices 10 are installed symmetrically with the center skeg 6 in between. The vessel propulsion devices 10 are installed so as to be located within the boundary layer X that is generated on the vessel bottom 5 on the stern 4 side when the vessel is sailing. The vessel propulsion device 10 includes a duct 20, a propeller 30, a connecting member 40 (see FIG. 4), and a fairing material 50.

[0015] (duct) The ducts 20 are provided on the bottom 5 of the hull 2. Multiple ducts 20 are lined up in the width direction W. In this embodiment, the multiple ducts 20 lined up in the width direction W are all positioned at the same position in the fore-and-aft direction D. Furthermore, four ducts 20 are provided per vessel propulsion device 10. All four ducts 20 are formed to have the same shape. Note that the term "same shape" as used here does not only mean shapes that are strictly the same, but also includes shapes that have dimensional errors.

[0016] As shown in FIG. 3, the duct 20 is formed in a cylindrical shape extending in the front-rear direction D. In this embodiment, the duct 20 is formed in a rectangular cylindrical shape with openings on both sides in the front-rear direction D. A flow F of a boundary layer X flows into the duct 20 from the front side Df to the rear side Da. In the following description, the opening on the front side Df of the duct 20 into which the flow F flows may be referred to as an inlet 21, and the opening on the rear side Da of the duct 20 from which the flow F flows out may be referred to as an outlet 22. The duct 20 is made of stainless steel. A propeller 30 is disposed inside each of the ducts 20 .

[0017] (propeller) The propeller 30 is rotatably disposed within the duct 20. The propeller 30 generates a flow in the longitudinal direction D within the duct 20. As a result, the propeller 30 generates a propulsive force in the longitudinal direction D on the boat 1. As a result, the boat 1 starts sailing toward the front side Df. The propeller 30 has a propeller shaft 31 and propeller blades 32. The propeller shaft 31 extends in the longitudinal direction D.

[0018] The front end of the propeller shaft 31 is formed into a curved surface. The rear end of the propeller shaft 31 is formed to be longer in the longitudinal direction D than the front end of the propeller shaft 31. A bearing (not shown) is provided on the outer circumferential surface of the propeller shaft 31. Propeller blades 32 are attached to the bearing of this propeller shaft 31 via a ring-shaped rim (not shown). This rim is connected to a drive source (not shown) provided on the bottom 5 of the ship. The rim rotates in the longitudinal direction D by the driving force transmitted from the drive source.

[0019] The propeller blades 32 are provided at a middle portion of the propeller shaft 31 in the longitudinal direction D. A plurality of the propeller blades 32 are provided in a line at equal intervals in the circumferential direction of the propeller shaft 31. The propeller blades 32 rotate around the propeller shaft 31 by the rotational drive of the rim (peripheral drive). This generates a flow in the longitudinal direction D within the duct 20. The propeller shaft 31 may be connected to a drive source, and the ends of the propeller blades 32 may be fixed to the propeller shaft 31. In this case, the propeller shaft 31 rotates by the drive force from the drive source, and the propeller blades 32 also rotate integrally with the propeller shaft 31 (center shaft drive).

[0020] (connector) As shown in FIG. 4 , the connecting member 40 is provided in the gap between the ducts 20. The connecting member 40 connects multiple ducts 20 lined up in the width direction W. The lower surface 41 of the connecting member 40 closes the gap between the ducts 20 from below. The lower surface 41 of the connecting member 40 is flush with the lower surface 25 of the outer surface 24 of the duct 20 and is smoothly connected. The connecting member 40 is made of stainless steel, the same material as the duct 20. The connecting member 40 is joined by welding. In this embodiment, the inside of the connecting member 40 is hollow. A structure (not shown) formed by multiple frames is provided in the hollow inside the connecting member 40. Fairing materials 50 are provided on the front side Df and rear side Da of the connecting member 40.

[0021] (fairing material) The fairing material 50 is provided on both the front side Df and the rear side Da between the ducts 20. The fairing material 50 is provided in all gaps between the ducts 20. The fairing material 50 is provided so as to close the gaps between the ducts 20 from the longitudinal direction D. The fairing material 50 is formed in a tapered shape when viewed from the vertical direction. Specifically, the dimension of the width direction W of the fairing material 50 decreases as it moves away from the duct 20 in the longitudinal direction D. The interior of the fairing material 50 is hollow. The lower surface 52 of the fairing material 50 is smoothly connected to the lower surface 25 of the outer surface 24 of the duct 20 via the lower surface 41 of the connecting material 40. More specifically, the lower surface 52 of the fairing material 50 is flush with the lower surface 25 of the outer surface 24 of the duct 20. The fairing material 50 has a pair of guide surfaces 51 that are each continuous with the inner surface 23 of the adjacent duct 20. The guide surfaces 51 are smoothly connected to the inner surface 23 of the duct 20. The pair of guide surfaces 51 protrude from the duct 20 in the front-to-rear direction D. That is, the pair of guide surfaces 51 are provided so as to face each other in the width direction W. The material of the fairing material 50 is stainless steel, the same as that of the duct 20. The fairing material 50 is joined to the duct 20 and the connecting material 40 by welding.

[0022] In the following description, the fairing material 50 on the front side Df of the gap between the ducts 20 may be referred to as the "front fairing material 50f," and the fairing material 50 on the rear side Da may be referred to as the "rear fairing material 50a." Also, the straight line that passes through the center of the gap between the ducts 20 in the width direction W and extends in the fore-and-aft direction D may be referred to as the "inter-duct center line C."

[0023] In this embodiment, the front fairing material 50f and the rear fairing material 50a are formed to have the same shape and are arranged symmetrically in the fore-and-aft direction D. The guide surfaces 51 are provided on both sides in the width direction W of the inter-duct center line C. The front end 53 of the front fairing material 50f and the rear end 54 of the rear fairing material 50a are both located on the inter-duct center line C. In the front fairing material 50f, the pair of guide surfaces 51 are curved toward the front side Df, jutting outward in the width direction W, and approach each other, intersecting at the front end 53. In the rear fairing material 50a, the pair of guide surfaces 51 are curved toward the rear side Da, jutting outward in the width direction W, and approach each other, intersecting at the rear end 54.

[0024] (Action and effect) The following describes the effects of the vessel propulsion device 10 of this embodiment. As shown in FIG. 1 , when a vessel 1 sails on water, a boundary layer X with a slow flow velocity is generated on the vessel bottom 5 on the stern 4 side according to the Reynolds number. The boundary layer X becomes thicker toward the rear Da (wake) (development of the boundary layer X). As the boundary layer X develops, the area with a slow flow velocity expands, resulting in a loss of momentum. In other words, the development of the boundary layer X is a factor in the deterioration of the propulsion performance of the vessel 1. In this embodiment, the flow F of the boundary layer X, which causes a loss of momentum, flows into the duct 20 and is accelerated by the propeller 30. This recovers the momentum loss, leading to an improvement in the propulsion performance of the vessel 1.

[0025] However, if a gap exists between adjacent ducts 20, the flow F may flow into this gap, increasing resistance. Therefore, it is necessary to block this gap, but if this gap is simply blocked with a plate-like member, stagnation points will occur over a wide area at the blocked portion on the front side Df, and the flow F will be more likely to separate at the blocked portion on the rear side Da, increasing resistance.

[0026] In contrast, in this embodiment, the vessel propulsion device 10 includes fairing materials 50 provided on both the front side Df and the rear side Da between the ducts 20. The fairing materials 50 each have a pair of guide surfaces 51 that are continuous with the inner surfaces 23 of adjacent ducts 20 and that protrude in the fore-and-aft direction D from the ducts 20. This prevents the flow F from entering the gaps between the ducts 20.

[0027] Furthermore, the dimension of the fairing material 50 in the width direction W decreases as it moves away from the duct 20 in the front-rear direction D.

[0028] Therefore, the front fairing material 50f provided on the front side Df between the ducts 20 can smoothly guide the flow F that strikes the fairing material 50 into the duct 20. In other words, because the leading end of the front side Df of the front fairing material 50f is tapered, the fluid resistance of the front fairing material 50f is reduced. Furthermore, the rear fairing material 50a provided on the rear side Da between the ducts 20 can smoothly merge the flow F exiting the duct 20. This suppresses turbulence of the flow F. Therefore, according to the marine vessel propulsion device 10 of this embodiment, the resistance of the front fairing material 50f can be reduced while the rear fairing material 50a can suppress turbulence of the flow F. In this way, propulsion performance is improved.

[0029] In this embodiment, the guide surface 51 is smoothly connected to the inner surface 23 of the duct 20 .

[0030] This allows the marine vessel propulsion device 10 to smooth the flow F near the boundary between the inner surface 23 of the duct 20 and the guide surface 51 of the fairing material 50. This prevents the flow F from separating at steps or sharp bends and the resulting generation of vortices, improving propulsion performance.

[0031] In this embodiment, the plurality of ducts 20 that make up the vessel propulsion device 10 are all formed in the same shape.

[0032] This allows the manufacturing costs of the vessel propulsion device 10 to be reduced compared to when the shapes of the ducts 20 are different.

[0033] In this embodiment, the fairing material 50 closes the gaps between the ducts 20 .

[0034] This makes it easier to adjust the gap between the ducts 20, and improves the degree of freedom in arranging the ducts 20 and the propellers 30.

[0035] In this embodiment, the fairing material 50 is hollow.

[0036] This allows the vessel propulsion device 10 to be made lighter.

[0037] Next, a modified example of the first embodiment will be described with reference to FIG. 5, the front fairing material 50f and the rear fairing material 50a may be formed in different shapes. In this modification, the front surface 53f of the front fairing material 50f is formed in a semicircular shape, and the rear surface 54a of the rear fairing material 50a is formed to protrude rearward longer than the front surface 53f of the front fairing material 50f. The fairing materials 50 on both sides in the front-rear direction D, together with the inner surface 23 of the duct 20, are arranged so that they form a streamlined shape extending in the front-rear direction D as viewed from the top-bottom direction.

[0038] According to this modification, the dimension of the rear fairing material 50a in the fore-and-aft direction D can be increased, allowing the flows F that have passed through adjacent ducts 20 to merge smoothly. This suppresses separation of the flows F, thereby suppressing an increase in resistance due to separation of the flows F.

[0039] Second Embodiment A vessel propulsion device 210 according to a second embodiment of the present disclosure will be described below with reference to Figures 6 and 7. Configurations similar to those in the first embodiment described above will be given the same names and reference numerals, and descriptions thereof will be omitted as appropriate.

[0040] 6, in this embodiment, the lower surface 225 of the outer surface 224 of the duct 220 extends in the front-rear direction D while curving so as to bulge downward at an intermediate portion in the front-rear direction D. The lower surface 225 of the front side Df of the duct 220 is slightly curved so as to be positioned upward as it approaches the front side Df. Furthermore, the lower surface 225 of the rear side Da of the duct 220 is curved so as to be positioned upward as it approaches the rear side Da. The outlet 222 of the rear side Da of the duct 220 has a smaller opening area than the inlet 221 of the front side Df of the duct 220.

[0041] 7, a pair of inner surfaces 223 of the duct 220 facing each other in the width direction W are formed in a convex shape that protrudes inward of the duct 220 at the middle part in the front-rear direction D.

[0042] 6, the lower surface 252 of the fairing material 250 curves to match the lower surface 225 of the outer surface 224 of the duct 220, and is smoothly connected to the lower surface 225 of the outer surface 224 of the duct 220 via the lower surface 41 of the connecting material 40. The lower surface 252 of the front fairing material 250f curves slightly upward from the lower surface 225 of the front side Df of the duct 220 toward the front side Df. The lower surface 252 of the rear fairing material 250a curves upward from the lower surface 225 of the rear side Da of the duct 220 toward the rear side Da.

[0043] 7, the guide surface 251 of the fairing material 250 is smoothly connected to the inner surface 223 of the duct 220. Furthermore, the guide surface 251 is formed so that the curvature of the guide surface 251 is equal to the curvature of the inner surface 223 of the duct 220.

[0044] The following describes the effects of the vessel propulsion device 210 of this embodiment. In this embodiment, the curvature of the guide surface 251 is equal to the curvature of the inner surface 223 of the duct 220 .

[0045] This allows the marine vessel propulsion device 210 to further smooth the flow F near the boundary between the inner surface 223 of the duct 220 and the guide surface 251 of the fairing material 250. Therefore, separation of the flow F that occurs at steps or sharp bends and the resulting generation of vortices are further suppressed, further improving propulsion performance.

[0046] In addition, in this embodiment, the lower surface 225 of the outer surface 224 of the duct 220 extends in the fore-and-aft direction D while curving downward at the middle portion in the fore-and-aft direction D, and the lower surface 252 of the fairing material 250 is smoothly connected to the lower surface 225 of the outer surface 224 of the duct 220.

[0047] This allows the vessel propulsion device 210 to smooth the flow F below the duct 220. Furthermore, separation of the flow F, which occurs at a step or a sharp bend, and the generation of vortices associated therewith are suppressed when the flow F below the duct 220 passes through the boundary between the duct 220 and the fairing material 250. Therefore, an increase in resistance in the duct 220 and the fairing material 250 is suppressed, further improving propulsion performance.

[0048] Third Embodiment A vessel propulsion device 310 according to a third embodiment of the present disclosure will be described below with reference to Figures 8 to 10. Configurations similar to those in the first embodiment described above will be given the same names and reference numerals, and descriptions thereof will be omitted as appropriate.

[0049] As shown in FIG. 8 , the underside of the vessel bottom 5 on which the vessel propulsion device 310 is installed is curved so as to be inclined relative to the horizontal plane. Specifically, the underside of the vessel bottom 5 on which the vessel propulsion device 310 is installed is curved so that the vertical position changes as it moves inward in the width direction W. Therefore, the ducts 20 installed on the underside of the vessel bottom 5 are arranged at an angle to each other. In this embodiment, the dimension of the gap in the width direction W between two ducts 20 gradually decreases as it moves downward. Therefore, when viewed from the fore-and-aft direction D, the fairing material 350 has a trapezoidal shape that tapers downward. In this embodiment as well, all of the multiple ducts 20 that make up one vessel propulsion device 310 are formed in the same rectangular cylindrical shape.

[0050] The dimension of the width direction W of the fairing material 350 changes in the vertical direction in accordance with the dimension of the width direction W of the gaps between the ducts 20. For example, the dimension of the width direction W of the fairing material 350 gradually decreases downward in accordance with the gaps between the ducts 20.

[0051] 9 and 10, the dimension of the fairing material 350 in the front-rear direction D varies in the up-down direction, increasing as the dimension of the width direction W of the gap between the ducts 20 increases. That is, the dimension of the fairing material 350 in the front-rear direction D gradually decreases downward to match the gap between the ducts 20. Therefore, each guide surface 351 of the fairing material 350 is formed in a trapezoidal shape when viewed from the width direction W, and the dimension of the guide surface 351 in the front-rear direction D gradually decreases downward. 10 is a view of the duct 20 and the fairing material 350 as viewed from below in the direction of arrow A shown in FIG.

[0052] Additionally, both the lower surface 352 of the fairing material 350 and the upper surface 355 of the fairing material 350 are formed in a semi-elliptical shape. The lower surface 352 of the fairing material 350 and the upper surface 355 of the fairing material 350 are similar to each other, and the upper surface 355 of the fairing material 350 is larger than the lower surface 352 of the fairing material 350.

[0053] In addition, the front end 353 of the front fairing material 350f is positioned gradually toward the rear Da as it extends downward, and the rear end 354 of the rear fairing material 350a is positioned gradually toward the front Df as it extends downward.

[0054] The following describes the effects of the vessel propulsion device 310 of this embodiment. If the underside of the vessel bottom 5 on which the vessel propulsion device 310 is installed is curved, and if the shapes of the ducts 20 differ, it will be more time-consuming to manufacture the vessel propulsion device 310, which could lead to increased costs. On the other hand, if all the ducts 20 have the same shape, manufacturing costs can be reduced, but gaps are more likely to occur between adjacent ducts 20. Furthermore, because the dimension of the width direction W of the gaps between the ducts 20 varies in the vertical direction, it is difficult to close the gaps between the ducts 20.

[0055] In contrast to this, in this embodiment, the fairing material 350 is formed so that the dimension in the width direction W of the fairing material 350 changes in the vertical direction in accordance with the dimension in the width direction W of the gap between the ducts 20.

[0056] As a result, even if ducts 20 of the same shape are installed on an inclined surface and the gap between the ducts 20 in the width direction W varies in the vertical direction, it is possible to sufficiently close only the gap between the ducts 20 with the fairing material 350. Therefore, it is possible to suppress a decrease in propulsion performance by closing the gap between the ducts 20 while keeping manufacturing costs down by using ducts 20 of the same shape.

[0057] In this embodiment, the dimension of the fairing material 350 in the front-rear direction D varies in the up-down direction, and increases as the dimension of the gap between the ducts 20 in the width direction W increases.

[0058] As a result, in areas where the dimension of the gap between the ducts 20 in the width direction W is large, the guide surface 351 becomes longer in the fore-and-aft direction D, which makes it possible to suppress separation of the flow F when it passes through the fairing material 350. This allows the marine vessel propulsion device 310 to avoid an increase in resistance caused by separation of the flow F. Furthermore, in areas where the dimension of the gap between the ducts 20 in the width direction W is small, the guide surface 351 becomes shorter in the fore-and-aft direction D, which reduces the resistance generated when the flow F passes through the fairing material 350.

[0059] <Fourth embodiment> A vessel propulsion device 410 according to a fourth embodiment of the present disclosure will be described below with reference to Figures 11 and 12. Configurations similar to those in the first embodiment described above will be given the same names and reference numerals, and descriptions thereof will be omitted as appropriate.

[0060] 11 and 12, the fairing material 450 is provided between ducts 20 of different sizes. For example, a case will be described in which, of two ducts 20 adjacent in the width direction W, the duct 20 on the outer side in the width direction W has smaller dimensions in the up-down direction and the width direction W than the duct 20 on the inner side in the width direction W, based on the center skeg 6. However, in this embodiment, these two ducts 20 have the same dimensions in the front-rear direction D.

[0061] The propeller 30 is arranged to have an appropriate size depending on the size of the duct 20. A relatively large propeller 30 is arranged in a large duct 20, and a relatively small propeller 30 is arranged in a small duct 20.

[0062] The lower surface 441 of the connecting material 440 and the lower surface 452 of the fairing material 450 are inclined so as to be positioned upward as they move outward in the width direction W. As a result, the lower surface 452 of the fairing material 450 is connected to the lower surfaces 25 of the outer surfaces 24 of the two ducts 20, which are different in size, via the lower surfaces 441 of the connecting material 440. Furthermore, of the two guide surfaces 451 of the fairing material 450, the guide surface 451 on the outer side in the width direction W across the center line C between the ducts is smaller than the guide surface 451 on the inner side in the width direction W.

[0063] Furthermore, the front end 453 of the front fairing material 450f and the rear end 454 of the rear fairing material 450a are both located on the center line C between the ducts.

[0064] The following describes the effects of the vessel propulsion device 410 of this embodiment. In this embodiment, the fairing material 450 is provided between ducts 20 of different sizes.

[0065] It is assumed that multiple ducts 20 of different sizes will be used depending on the thickness of the boundary layer X that occurs on the ship bottom 5 on the stern 4 side. According to this embodiment, even when ducts 20 of different sizes are adjacent to each other, by providing a fairing material 450 between these ducts 20, it is possible to smooth the flow F near the boundary between the inner surface 23 of the duct 20 and the guide surface 451 of the fairing material 450. Therefore, even in such a case, the marine vessel propulsion device 410 can easily collect the flow F of the boundary layer X inside the duct 20, improving the propulsion performance of the marine vessel propulsion device 410.

[0066] Next, a modification of the fourth embodiment will be described with reference to FIGS. As shown in FIG. 13, the front end 453 of the front fairing material 450f and the rear end 454 of the rear fairing material 450a may both be located closer to the small duct 20 than the center line C between the ducts.

[0067] 14, two ducts 20 of different sizes may be formed to have similar shapes. In this case, the dimensions of the smaller duct 20 in the width direction W, the up-down direction, and the front-rear direction D are smaller than the dimensions of the larger duct 20 in the width direction W, the up-down direction, and the front-rear direction D. Furthermore, of the two guide surfaces 451 of the fairing material 450, the guide surface 451 on the smaller duct 20 side is longer in the front-rear direction D than the guide surface 451 on the larger duct 20 side. In this case, the front end 453 of the front fairing material 450f and the rear end 454 of the rear fairing material 450a may both be located on the smaller duct 20 side or the larger duct 20 side of the inter-duct center line C.

[0068] (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.

[0069] In the above embodiment, the interior of the connecting members 40, 440 is hollow, but this is not limited thereto. The connecting members 40, 440 may be solid. Furthermore, although a structure formed of multiple frames is provided in the hollow inside the connecting members 40, 440, such a structure or the like may not be provided in the hollow inside the connecting members 40, 440. Furthermore, the connecting members 40, 440 may be formed in a plate shape that connects only the lower sides of the ducts 20, 220 adjacent to each other in the width direction W. Furthermore, the connecting members 40, 440 may not be provided between the adjacent ducts 20, 220.

[0070] In the above embodiment, the fairing materials 50, 250, 350, 450 are provided in all gaps between the ducts 20, 220, but this is not limiting. It is preferable that the fairing materials 50, 250, 350, 450 are provided in all gaps between the ducts 20, 220, but the fairing materials 50, 250, 350, 450 may be provided only in some of the gaps between the ducts 20, 220.

[0071] In the above embodiment, the fairing materials 50, 250, 350, 450 are provided on both the front side Df and the rear side Da between the ducts 20, 220, but this is not limited thereto. For example, if the ducts 20, 220 are arranged at an angle with respect to the longitudinal direction D, the fairing materials 50, 250, 350, 450 may be provided on only one of the front side Df and the rear side Da between the ducts 20, 220.

[0072] In the above-described embodiment, the fairing materials 50, 250, 350, and 450 are hollow inside, but this is not limiting. The fairing materials 50, 250, 350, and 450 may be solid.

[0073] In the above embodiment, the fairing materials 50, 250, 350, and 450 are made of stainless steel, but the material is not limited to this. The fairing materials 50, 250, 350, and 450 may be made of a steel material other than stainless steel or a composite material (FRP; Fiber Reinforced Plastics).

[0074] In the above embodiment, the multiple ducts 20, 220 aligned in the width direction W are all arranged at the same position in the front-rear direction D, but this is not limited to this. The multiple ducts 20, 220 aligned in the width direction W may be offset from each other in the front-rear direction D as long as they overlap in the width direction W.

[0075] <Additional Notes> The vessel propulsion devices 10, 210, 310, 410 and the vessel 1 described in each embodiment can be understood, for example, as follows.

[0076] (1) A vessel propulsion device 10, 210, 310, 410 according to a first aspect includes a plurality of ducts 20, 220 arranged on the bottom 5 of a hull 2 ​​and aligned in a width direction W intersecting with a longitudinal direction D of the hull 2, a propeller 30 rotatably disposed inside each of the ducts 20, 220 and generating a flow in the longitudinal direction D within the ducts 20, 220, and a propeller 30 disposed on at least one of a front side Df and a rear side Da between the ducts 20, 220, and fairing materials 50, 250, 350, 450 each having a pair of guide surfaces 51, 251, 351, 451 that are continuous with the inner surfaces 23, 223 of the adjacent ducts 20, 220 and protrude from the ducts 20, 220 in the fore-and-aft direction D, and the dimension of the fairing materials 50, 250, 350, 450 in the width direction W becomes smaller as they move away from the ducts 20, 220 in the fore-and-aft direction D.

[0077] The fairing materials 50, 250, 350, 450 provided on the front side Df between the ducts 20, 220 can smoothly guide the flow F that collides with the fairing materials 50, 250, 350, 450 into the ducts 20, 220. In addition, the fairing materials 50, 250, 350, 450 provided on the rear side Da between the ducts 20, 220 can smoothly merge the flow F that comes out of the ducts 20, 220.

[0078] (2) The vessel propulsion device 10, 210, 310, 410 of the second aspect is the vessel propulsion device 10, 210, 310, 410 of (1), and the fairing material 50, 250, 350, 450 may be provided on both the front side Df and the rear side Da between the ducts 20, 220.

[0079] This allows the flow F that collides with the fairing material 50, 250, 350, 450 to be smoothly guided into the ducts 20, 220, while allowing the flow F that leaves the ducts 20, 220 to smoothly merge with it.

[0080] (3) The vessel propulsion device 10, 210, 310, 410 of the third aspect is the vessel propulsion device 10, 210, 310, 410 of (1) or (2), and the guide surface 51, 251, 351, 451 may be smoothly connected to the inner surface 23, 223 of the duct 20, 220.

[0081] This allows the vessel propulsion device 10, 210, 310, 410 to smooth the flow F near the boundary between the inner surface 23, 223 of the duct 20, 220 and the guide surface 51, 251, 351, 451 of the fairing material 50, 250, 350, 450.

[0082] (4) A fourth aspect of the vessel propulsion device 210 is the vessel propulsion device 210 of (3), wherein the curvature of the guide surface 251 may be equal to the curvature of the inner surface 223 of the duct 220.

[0083] This allows the vessel propulsion device 210 to make the flow F near the boundary between the inner surface 223 of the duct 220 and the guide surface 251 of the fairing material 250 even smoother.

[0084] (5) A fifth aspect of the vessel propulsion device 210 is a vessel propulsion device 210 according to any one of (1) to (4), wherein the underside 225 of the outer surface 224 of the duct 220 extends in the fore-and-aft direction D while curving downwardly at the middle of the fore-and-aft direction D, and the underside 252 of the fairing material 250 may be smoothly connected to the underside 225 of the outer surface 224 of the duct 220.

[0085] This allows the vessel propulsion device 210 to smooth the flow F below the duct 220. Furthermore, when the flow F below the duct 220 passes through the boundary between the duct 220 and the fairing material 250, separation of the flow F, which occurs at a step or a sharp bend, and the generation of a vortex associated therewith are suppressed.

[0086] (6) The sixth aspect of the vessel propulsion device 310 is any one of the vessel propulsion devices 310 of (1) to (5), and the dimension of the fairing material 350 in the fore-and-aft direction D may vary in the up-and-down direction and may become larger as the dimension of the width direction W of the gap between the ducts 20 becomes larger.

[0087] As a result, in areas where the dimension of the width direction W of the gap between the ducts 20 is large, the guide surface 351 becomes longer in the front-rear direction D, and separation of the flow F when passing through the fairing material 350 can be suppressed.

[0088] (7) The vessel propulsion device 410 of the seventh aspect is any one of the vessel propulsion devices 410 of (1) to (6), and the fairing material 450 may be provided between the ducts 20 of different sizes.

[0089] It is assumed that multiple ducts 20 of different sizes will be used depending on the thickness of the boundary layer X that occurs on the bottom 5 of the ship on the stern 4 side. According to this aspect, even when ducts 20 of different sizes are adjacent to each other, by providing a fairing material 450 between these ducts 20, the flow F near the boundary between the inner surface 23 of the duct 20 and the guide surface 451 of the fairing material 450 can be made smooth.

[0090] (8) A vessel 1 according to an eighth aspect includes the vessel propulsion device 10, 210, 310, 410 according to any one of (1) to (7) and the hull 2. [Explanation of symbols]

[0091] 1...vessel 2...hull 3...bow 4...stern 5...bottom 6...center skeg 10...marine propulsion device 20...duct 21...inlet 22...outlet 23...inner surface 24...outer surface 25...underside 30...propeller 31...propeller shaft 32...propeller blade 40...connecting material 41...underside 50...fairing material 50f...front fairing material 50a...rear fairing material 51...guide surface 52...underside 53...front end 53f...front side 54...rear end 54a...rear side 210...marine propulsion device 220...duct 221...inlet 222...outlet 223...inner surface 224...outer surface 225...underside 250...fairing material 250f...front fairing material 250a...Rear fairing material 251...Guide surface 252...Lower surface 310...Marine propulsion device 350...Fairing material 350f...Front fairing material 350a...Rear fairing material 351...Guide surface 352...Lower surface 353...Front end 354...Aft end 355...Upper surface 410...Marine propulsion device 440...Connecting material 441...Lower surface 450...Fairing material 450f...Front fairing material 450a...Aft fairing material 451...Guide surface 452...Lower surface 453...Front end 454...Aft end C...Center line between ducts D...Fore-aft direction Df...Fore side Da...Aft side F...Flow W...Span direction X...Boundary layer

Claims

1. A plurality of ducts are provided on the bottom of the hull and arranged in a width direction intersecting the fore-and-aft direction of the hull; a propeller rotatably disposed inside each of the ducts to generate a flow in the longitudinal direction within the duct; a fairing material provided on at least one of the front and rear sides between the ducts, the fairing material having a pair of guide surfaces that are continuous with the inner surfaces of the adjacent ducts and that protrude from the ducts in the fore-and-aft direction; Equipped with a widthwise dimension of the fairing material that decreases as it moves away from the duct in the front-rear direction; a lower surface of the outer surface of the duct extends in the front-rear direction while curving so as to protrude downward at an intermediate portion in the front-rear direction, The lower surface of the fairing material is smoothly connected to the lower surface of the outer surface of the duct. Ship propulsion system.

2. A plurality of ducts are provided on the bottom of the hull and arranged in a width direction intersecting the fore-and-aft direction of the hull; a propeller rotatably disposed inside each of the ducts to generate a flow in the longitudinal direction within the duct; a fairing material provided on at least one of the front and rear sides between the ducts, the fairing material having a pair of guide surfaces that are continuous with the inner surfaces of the adjacent ducts and that protrude from the ducts in the fore-and-aft direction; Equipped with a widthwise dimension of the fairing material that decreases as it moves away from the duct in the front-rear direction; The fairing material is provided between the ducts of different sizes. Ship propulsion system.

3. The fairing material is provided on both the front and rear sides between the ducts.

3. A vessel propulsion device according to claim 1 or 2.

4. The guide surface is smoothly connected to the inner surface of the duct.

3. A vessel propulsion device according to claim 1 or 2.

5. The curvature of the guide surface is equal to the curvature of the inner surface of the duct.

5. A marine vessel propulsion device according to claim 4.

6. The dimension of the fairing material in the front-to-rear direction varies in the up-down direction, and increases as the dimension of the gap between the ducts in the width direction increases.

3. A vessel propulsion device according to claim 1 or 2.

7. The vessel propulsion device according to claim 1 or 2; The hull; A vessel equipped with:

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