CN110770117B - Tail fin and ship with same - Google Patents
Tail fin and ship with same Download PDFInfo
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- CN110770117B CN110770117B CN201880039075.7A CN201880039075A CN110770117B CN 110770117 B CN110770117 B CN 110770117B CN 201880039075 A CN201880039075 A CN 201880039075A CN 110770117 B CN110770117 B CN 110770117B
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- propeller
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- fin
- hull
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H1/00—Propulsive elements directly acting on water
- B63H1/02—Propulsive elements directly acting on water of rotary type
- B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
- B63H1/14—Propellers
- B63H1/28—Other means for improving propeller efficiency
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
- B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
- B63H5/16—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in recesses; with stationary water-guiding elements; Means to prevent fouling of the propeller, e.g. guards, cages or screens
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- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
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- Ocean & Marine Engineering (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
And a tail fin which is provided with a propeller and is attached to a side surface of a stern of a ship having a Froude number of 0.17 or more at a planned speed, wherein the tail fin is positioned on a forward side in a traveling direction of the ship from the propeller and in a position near a height of a rotation shaft of the propeller, a center line obtained by sequentially connecting midpoints of an upper surface and a lower surface of the tail fin in a cross-sectional shape of the tail fin perpendicular to a projecting direction in which the tail fin projects from the side surface of the stern projects downward, and a maximum projecting length of the tail fin from the side surface of the stern in the projecting direction is 2% or more and 15% or less of a diameter of the propeller.
Description
Technical Field
The present invention relates to a stern fin mounted on a stern portion of a relatively fast ship, for example, on a stern portion of a ship having a planned speed with a froude number of 0.17 or more, and a ship provided with the stern fin.
Background
Generally, when a ship is underway, bilge vortex is generated in front of a propeller at the stern of the ship. Bilge vortices result in increased drag when the vessel is underway. Therefore, in order to improve the propulsion efficiency of a ship, there have been attempts to provide fins at the stern of the hull and to reduce the bilge vortex, or to use the bilge vortex for the propulsion of the ship.
Prior art documents
Patent document
Patent document 1: japanese patent No. 3477564
Disclosure of Invention
Problems to be solved by the invention
In a relatively high-speed ship (for example, a ship having a planned cruising speed with a froude number of 0.17 or more), bilge vortex may not be generated, and even if bilge vortex is generated, the rotational energy of the bilge vortex is weaker than that of a low-speed ship. Therefore, even if the stern fin designed to position the wing end portion at the substantially central position of the bilge vortex is mounted on the stern portion, the propulsive assistance effect based on the conversion of the rotational energy of the bilge vortex into the thrust force is small. Conversely, since the speed is relatively high and the resistance of the stern fin itself is large, the presence of the stern fin adversely affects the propulsion of the ship. Therefore, a design suitable for a fast ship is required for a stern fin which is required to reliably improve the efficiency of assisting the ship propulsion.
Accordingly, an object of the present invention is to provide a stern fin that is attached to a stern portion of a high-speed ship and can reliably improve efficiency of assisting propulsion of the ship, and a ship provided with the stern fin.
Means for solving the problems
In order to solve the above problem, a stern fin according to the present invention is provided with a propeller, and is attached to a side surface of a stern portion of a ship having a froude number of 0.17 or more at a planned speed, the stern fin is located on a forward side in a traveling direction of the ship from the propeller and in a position near a height of a rotation shaft of the propeller, a center line obtained by sequentially connecting midpoints of upper and lower surfaces of the stern fin in a cross-sectional shape of the stern fin perpendicular to a projecting direction in which the stern fin projects from the side surface of the stern portion projects downward, and a maximum projecting length of the stern fin from the side surface of the stern portion in the projecting direction is 2% or more and 15% or less of a diameter of the propeller.
According to the above configuration, the maximum extension length of the stern fin extending from the side surface of the stern portion in the extending direction is 15% or less of the diameter of the propeller, and the stern fin is provided in a region where the flow speed is low.
For example, the cross-sectional shape of the skeg is an airfoil.
The stern fin may be configured such that a trailing edge of the stern fin is located on a rear side in the traveling direction of the ship with respect to a position away from the propeller toward a front side in the traveling direction of the ship by 2 times a diameter of the propeller. The down-flow near the hull is slow due to the effect of viscosity. However, according to this configuration, since the stern fin is disposed in the vicinity of the front of the propeller, the stern fin can be subjected to a faster water flow even in the vicinity of the hull by the suction effect of the propeller to be driven. This can increase the thrust force generated by the stern fin receiving the downward flow.
The stern fin may be configured such that, when the lowest point of the stern fin is located above a height of a rotation shaft of the propeller, a vertical distance from the lowest point to the height of the rotation shaft is 10% or less of a diameter of the propeller, and when the lowest point is located below the height of the rotation shaft, the vertical distance from the lowest point to the height of the rotation shaft is 30% or less of the diameter of the propeller. The down-flow near the hull is slow due to the effect of viscosity. However, according to this configuration, since the stern fin is disposed in the vicinity of the front of the propeller, the stern fin can be subjected to a faster water flow even in the vicinity of the hull by the suction effect of the propeller to be driven. This can increase the thrust force generated by the stern fin receiving the downward flow.
The stern fin may be configured such that an average length from a leading edge to a trailing edge of the stern fin in a fore-and-aft direction of the ship is 50% or less of a diameter of the propeller. When the length from the leading edge to the trailing edge of the tail fin in the fore-and-aft direction of the ship becomes longer than a certain length, the influence of the drag generated by the water flow received by the tail fin becomes larger than the thrust generated by the down flow received by the tail fin. According to this structure, since the average length from the leading edge to the trailing edge of the skeg is limited to 50% or less of the diameter of the propeller in the fore-and-aft direction of the ship, the influence of the drag of the skeg due to the water flow can be reduced, and the thrust of the skeg due to the down flow can be increased.
The ship of the present invention is a ship including the above-described tail fin.
Effects of the invention
According to the present invention, it is possible to provide a stern fin capable of reliably improving the efficiency of assisting the propulsion of a ship, and a ship provided with the stern fin.
Drawings
Fig. 1 is a schematic side view of a stern portion of a ship according to an embodiment.
Fig. 2 is a sectional view taken along line II-II in fig. 1, showing the flow of water on the right side of the stern of the ship.
Fig. 3 is an enlarged side view of the skeg of fig. 1.
Fig. 4 is a sectional view taken along line IV-IV in fig. 1.
Fig. 5 is a graph showing the results of tests conducted by the present inventors and the like.
Fig. 6 is a schematic view of a stern portion of a ship according to another embodiment as viewed from behind.
Fig. 7A is an example of a wake distribution diagram showing the water flow on the right side of the propeller at the propeller position of the low-speed ship.
Fig. 7B is an example of a wake flow distribution diagram showing the water flow on the right side of the propeller at the propeller position of a medium speed ship.
Fig. 7C is an example of a wake distribution diagram showing the flow of water on the right side of the propeller at the propeller position of the high-speed ship.
Detailed Description
(the focus of the invention)
First, the gist of the present invention will be described with reference to fig. 7A to 7C. Fig. 7A is an example of a wake distribution diagram showing the flow of water on the right side of the propeller at the position of the propeller of a low-speed ship with a relatively low speed. Fig. 7B is an example of a wake flow distribution diagram showing the water flow on the right side of the propeller at the position of the propeller of the medium-speed ship with a relatively high speed. Fig. 7C is an example of a wake pattern showing the flow of water on the right side of the propeller at the position of the propeller of a high-speed ship whose speed is fast.
In the present specification, a low-speed ship refers to a ship having a planned cruising speed with a froude number Fn of less than 0.17, a medium-speed ship refers to a ship having a planned cruising speed with a froude number Fn of 0.17 or more and less than 0.19, and a high-speed ship refers to a ship having a planned cruising speed with a froude number Fn of 0.19 or more. The Froude number Fn is represented by the following formula.
Fn＝U/(L×g)1/2
And U is the planned speed [ m/s ]]L is the length of the water line [ m ]]G is the acceleration of gravity [ m/s ]2]。
In fig. 7A to 7C, X, Y, and Z axes perpendicular to each other are shown. The Z-axis is shown to extend in the vertical direction of the ship in accordance with the center line of the ship. The Y-axis is shown as passing through the propeller axis and extending in the width direction of the vessel. The X-axis is shown extending in the direction of the length of the vessel in line with the propeller axis. The vectors shown in fig. 7A to 7C represent the direction and magnitude of the water flow in the YZ plane. In addition, the contour lines shown in fig. 7A and 7B represent the distribution of the water flow in the XZ plane. The contours are lines connecting points at which the ratio of the X component of the water flow velocity to the ship speed (more specifically, the planned ship speed) is equal, and the ratio is indicated in the vicinity of each contour. In fig. 7A to 7C, circles drawn by the blade ends of the blade portions (blades) of the propeller when the blade portions are rotated are shown by broken lines.
In the wake flow distribution diagram of the low-speed ship shown in fig. 7A, as indicated by the YZ plane vector, the vertical flows intersect at a position at a predetermined distance from the hull center line in the vicinity of the height of the propeller rotation axis, in other words, in the vicinity of the Y axis, and a rotating flow, that is, a bilge vortex is generated. As is clear from the contour line in fig. 7A, the vicinity of the vortex is a region in which the ratio of the flow velocity of water to the X component of the ship speed (i.e., the relative speed of water to the ship hull in the ship length direction) is small. In this way, even if the stern fin is protruded to the center of the bilge vortex in the low-speed ship, the flow velocity of water is reduced as it goes from the hull to the vortex, and the stern fin itself is less likely to become a resistance.
On the other hand, in the wake distribution diagram of the medium speed ship shown in fig. 7B and the wake distribution diagram of the high speed ship shown in fig. 7C, as indicated by the vector of the YZ plane, the clear eddy current as shown in fig. 7A is not observed. Further, as is clear from the contour lines in fig. 7B and 7C, the region where the flow velocity of water is slow as shown in fig. 7A does not occur at a position away from the center line of the hull, but the flow velocity of water increases as the distance from the hull increases, unlike the low-speed ship. Therefore, the present inventors have considered that in a medium-speed ship and a high-speed ship in which the froude number Fn of the planned speed is 0.17 or more, the stern fin designed to have a large length protruding from the hull may adversely affect the propulsion of the ship because the resistance of the stern fin itself becomes large. The present invention has been made in view of the above points.
(embodiment mode)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Fig. 1 is a schematic side view of a stern portion 3 of a ship 1A according to an embodiment. The ship 1A of the present embodiment is a medium-speed ship or a high-speed ship with a planned cruising speed having a froude number Fn of 0.17 or more. The ship 1A is a single-shaft ship having a propeller 4 provided at the center of the hull 2.
As shown in fig. 1, the propeller 4 is disposed at the stern portion 3 of the hull 2, and the propeller 4 is provided at the stern portion 3. In the present specification, the "stern portion" refers to a portion of the hull 2 that occupies 40% of the ship length forward from the propeller 4. The propeller 4 has: a shaft portion 5 extending in the ship length direction and projecting rearward from the hull 2; and a plurality of blade portions 6 arranged circumferentially around the shaft portion 5. The propeller 4 rotates about a rotation axis SC extending along the shaft portion 5. Further, the rudder 7 is disposed behind the propeller 4 in the stern portion 3.
A pair of tail fins 10 are provided on the forward side (bow side) of the hull 2 in the traveling direction with respect to the propeller 4. The skeg 10 receives a downward flow Sa flowing diagonally downward and rearward along the surface of the hull 2 for assisting the propulsion of the ship 1A.
FIG. 2 is a sectional view taken along line II-II in FIG. 1. The pair of tail fins 10 are attached to the hull 2 so as to horizontally extend in the left-right direction (i.e., the ship width direction) from each of the left and right side surfaces of the stern 3. In fig. 2, only the right side of the stern portion 3 is shown for simplicity, and the left side of the stern portion 3 is omitted. As shown in fig. 2, a downward flow Sa flowing diagonally downward and rearward along the surface of the hull 2 is generated in the vicinity of the surface of the stern 3 of the ship 1A, and an upward flow Sb flowing diagonally upward and rearward is generated in a portion away from the surface of the stern 3.
Fig. 3 is an enlarged side view of the skeg 10 of fig. 1. As shown in fig. 3, the sectional shape of the skeg 10 perpendicular to the protruding direction in which the skeg 10 protrudes from the side surface of the hull 2 is an airfoil. A center line (beam arch line) L1 obtained by sequentially connecting midpoints of the upper surface 14 and the lower surface 15 of the stern fin 10 is projected downward. That is, the center line L1 is a line that is equidistant from the upper surface 14 and the lower surface 15 in the up-down direction.
Further, the tail fin 10 is attached to the side surface of the hull 2 such that the leading edge 11 thereof is located above the trailing edge 12. Specifically, the skeg 10 is attached to the hull 2 such that a chord line (boundary line) L2, which is a straight line connecting the leading edge 11 and the trailing edge 12, substantially follows the downward flow Sa. For example, the tail fin 10 is attached to the hull 2 so that an angle (attachment angle) θ 1 of the chord line L2 with respect to the horizontal plane satisfies the following expression (1).
0°＜θ1≤20° (1)
Since the skeg 10 takes such a shape and posture (installation angle), the skeg 10 receives the downflow Sa flowing near the hull 2, and generates the lift force F diagonally forward as shown in fig. 3. The forward component Fa of the lift force F is used for propulsion of the ship 1A.
Fig. 4 is a sectional view taken along line IV-IV in fig. 1. In fig. 4, the left side of the stern portion 3 is omitted for simplicity, and the propeller 4 is omitted. The leading edge 11 and the trailing edge 12 of the skeg 10 extend in the ship width direction from the side surfaces of the hull 2. More specifically, the leading edge 11 extends at a predetermined angle (retreating angle) θ 2 rearward with respect to a direction perpendicular to a center line CL in the lateral direction of the hull 2, and the trailing edge 12 extends perpendicular to the center line CL of the hull 2. The wing end 13 of the tail fin 10 extends parallel to the ship length direction so as to connect the ends of the leading edge 11 and the trailing edge 12 that are located on the far side of the hull 2 to each other.
In the present embodiment, the stern fin 10 is limited so that the ratio of the maximum protruding length W to the diameter D of the propeller 4 is within a predetermined range. Specifically, the maximum protruding length W of the skeg 10 from the side surface of the hull 2 in the protruding direction (the ship width direction in the present embodiment) perpendicular to the ship length direction is 2% or more and 15% or less, and more preferably 4% or more and 10% or less of the diameter D of the propeller 4. That is, the maximum protruding length W of the skeg 10 in the protruding direction from the side surface of the hull 2 satisfies at least the following formula (2).
W≤D×0.15 (2)
The maximum projecting length is a value at which the length in the projecting direction from the wing root (i.e., the portion from the proximal end 11a of the hull 2 at the leading edge 11 to the proximal end 12a of the hull 2 at the trailing edge 12) to the wing end 13 of the skeg 10 is the maximum.
The ratio of the maximum protrusion length W to the diameter D of the propeller 4 will be described with reference to fig. 5. Fig. 5 is a graph showing the results of experiments conducted by the present inventors on a low-speed ship having a froude number Fn of 0.14, a medium-speed ship having a froude number Fn of 0.17, and a high-speed ship having a froude number Fn of 0.20. The horizontal axis of the graph of fig. 5 indicates the ratio of the maximum protruding length W of the stern fin 10 to the diameter D of the propeller 4 (hereinafter referred to as "protruding amount", in units of "%"). That is, the extension is a value of the maximum extension W of the stern fin 10 when the diameter D of the propeller 4 is 100, and can be calculated by the equation of "maximum extension ÷ propeller diameter × 100". The vertical axis of the graph of fig. 5 shows the efficiency of the propulsion of the auxiliary vessel 1A, specifically, the horsepower required for the rotation of the propeller 4 to cause the hull 2 to travel at a predetermined speed, and the horsepower reduction rate (hereinafter referred to as "horsepower reduction rate") when the stern fin 10 is attached to the hull 2, compared to the horsepower when the stern fin 10 is not attached to the hull 2.
As shown in fig. 5, in the case of a low-speed ship, in the range where the overhang amount is 30% or less, the horsepower reduction rate becomes larger as the overhang amount becomes larger. On the other hand, in the case of a medium-speed ship or a high-speed ship, the horsepower reduction rate increases as the overhang amount increases, and gradually decreases after a certain value of 2% to 15% reaches a maximum. In the case of a medium-speed ship or a high-speed ship, the horsepower reduction rate at least in the range where the overhang amount is 2% or more and 15% or less is larger than the horsepower reduction rate in the other range. That is, as is apparent from fig. 5, if the protruding amount is at least in the range of 2% to 15%, a sufficient horsepower reduction rate can be obtained without adversely affecting the propulsion of the ship 1A.
Returning to fig. 4, in the present embodiment, the lower portion of the stern portion 3 of the hull 2 is formed to be thinner toward the rear. Therefore, the protruding length of the skeg 10 in the protruding direction from the side surface of the hull 2 is largest at the trailing edge 12 extending perpendicularly with respect to the center line CL of the hull 2. That is, in the present embodiment, the maximum projecting length W of the stern fin 10 is a length from the end 12a on the near side to the hull 2 at the trailing edge 12 to the end 12b on the far side to the hull 2.
When the length from the leading edge 11 to the trailing edge 12 of the skeg 10 in the fore-and-aft direction of the hull 2 is longer than a certain length, the influence of the drag generated by the water flow received by the skeg 10 becomes larger than the thrust generated by the skeg 10 receiving the downward flow Sa. Therefore, in the present embodiment, the longitudinal length of the stern fin 10 is limited to a certain length or less.
Specifically, the average Ea of the lengths from the leading edge 11 to the trailing edge 12 of the skeg 10 in the fore-and-aft direction of the hull 2 is limited to 50% or less of the diameter D of the propeller 4. In the present embodiment, the leading edge 11 extends obliquely rearward with respect to the direction perpendicular to the center line CL of the hull 2, and the trailing edge 12 extends perpendicularly with respect to the center line CL of the hull 2, so that the length of the stern fin 10 from the leading edge 11 to the trailing edge 12 becomes shorter as it is farther from the hull 2. That is, the length in the fore-and-aft direction of the hull 2 from the leading edge 11 to the trailing edge 12 of the skeg 10 is largest at the proximal side end 11a to the hull 2 at the leading edge 11, and smallest at the distal side end 11b to the hull 2 at the leading edge 11. In the present embodiment, since the front edge 11 and the rear edge 12 are linear in plan view, assuming that the length from the end 11a of the front edge 11 to the rear edge 12 is E1 and the length from the end 11b of the front edge 11 to the rear edge 12 is E2, the average Ea of the lengths from the front edge 11 to the rear edge 12 can be expressed by the following expression (3).
Ea＝(E1+E2)/2 (3)
The stern fin 10 is attached so that the average Ea of the lengths from the leading edge 11 to the trailing edge 12 is 50% or less of the diameter D of the propeller 4, that is, so as to satisfy the following expression (4).
Ea≤D×0.5 (4)
The downflow Sa near the hull is slow due to the influence of viscosity. In the present embodiment, the stern fin 10 is disposed in the vicinity of the front of the propeller 4 and in the vicinity of the height of the rotation axis SC of the propeller 4 so as to receive a faster water flow even in the vicinity of the hull 2 by utilizing the suction effect of the propeller 4 being driven. Here, the vicinity of the height of the rotation axis SC of the propeller 4 means a range in which the vertical distance H to the height of the rotation axis SC of the propeller 4 is 30% or less of the diameter D of the propeller 4, and when the lowest point of the stern fin 10 is located within this range, the stern fin 10 is disposed in the vicinity of the height of the rotation axis SC of the propeller 4.
In the case where the lowest point of the stern fin 10 is located above the height of the rotation axis SC of the propeller 4, the vertical position of the stern fin 1 is preferably such that the vertical distance H from the lowest point to the height of the rotation axis SC is 10% or less of the diameter D of the propeller 4, and the stern fin 10 is disposed on the hull 2. Further, when the lowest point of the stern fin 10 is located below the height of the rotation axis SC of the propeller 4, the stern fin 10 is preferably disposed on the hull 2 such that the vertical distance H from the lowest point to the height of the rotation axis SC is 30% or less of the diameter D of the propeller 4. In the present embodiment, as shown in fig. 1, the stern fin 10 is disposed on the hull 2 so that the lowest point thereof coincides with the height of the rotation axis SC of the propeller 4. In other words, the stern fin 10 of the present embodiment is disposed such that the vertical distance H from the lowest point of the stern fin 10 to the height of the rotation axis SC of the propeller 4 is zero. Since the distance H is zero, the distance H is omitted in fig. 1.
Further, with respect to the fore-and-aft direction of the stern fin 1, the rear edge 12 of the stern fin 10 is located on the rear side in the traveling direction of the hull 2 with respect to a position away from the propeller 4 toward the front side in the traveling direction of the hull 2 by 2 times the diameter D of the propeller 4. In other words, the distance G in the fore-and-aft direction of the hull 2 from the shaft portion 5 of the propeller 4 to the rear edge 12 of the stern fin 10 shown in fig. 1 is 2 times or less the diameter D of the propeller 4, and satisfies the following expression (5).
G≤D×2.0 (5)
As described above, in the ship 1A of the medium or high speed ship including the skegs 10 according to the present embodiment, the maximum extension length W of the skegs extending from the side surfaces of the hull 2 of the skegs 10 in the extending direction is 15% or less of the diameter D of the propeller 4, and the skegs are provided in a region where the flow speed is slow, so that the resistance generated by the skegs 10 themselves can be reduced, and the efficiency of assisting the propulsion of the ship 1A can be reliably improved.
In the present embodiment, the trailing edge 12 of the stern fin 10 is located on the rear side in the traveling direction of the hull 2 with respect to the position away from the propeller 4 toward the front side in the traveling direction of the hull 2 by 2 times the diameter D of the propeller 4. The stern fin 10 is disposed on the hull 2 so that the vertical distance H from the lowest point to the height of the rotation axis SC of the propeller 4 is limited to a predetermined range. Since the skegs 10 are disposed in the vicinity of the front of the propeller 4 in this way, the skegs 10 can receive a faster water flow even in the vicinity of the hull 2 due to the suction effect of the propeller 4 that drives. This can increase the thrust force generated by the skeg 10 receiving the downward flow Sa.
In addition, in the present embodiment, since the average value of the lengths from the leading edge 11 to the trailing edge 12 of the skeg 10 in the fore-and-aft direction of the hull 2 is limited to 50% or less of the diameter D of the propeller 4, the influence of the resistance of the skeg 10 due to the water flow can be reduced, and the thrust of the skeg 10 due to the downward flow Sa can be increased.
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the sectional shape of the tail fin 10 perpendicular to the extending direction is an airfoil shape, but the shape of the tail fin of the present invention is not limited thereto, and it is sufficient if a center line obtained by sequentially connecting the midpoints of the upper surface and the lower surface of the tail fin is projected downward. For example, the fin of the present invention may be a plate-like member that protrudes downward as a whole in a cross-sectional shape perpendicular to the protruding direction, and the vertical thickness of the upper and lower surfaces of the fin is substantially constant from the leading edge to the trailing edge.
The mounting position and size of the tail fin 10 are not limited to those in the above embodiments. For example, the rear edge 12 of the stern fin 10 may be spaced from the propeller 4 to the forward side in the traveling direction of the hull 2 by a distance 2 times the diameter D of the propeller 4, and when the lowest point of the stern fin 10 is located above the height of the rotation axis SC of the propeller 4, the vertical distance H from the lowest point of the stern fin 10 to the height of the rotation axis SC of the propeller 4 may be greater than 10% of the diameter D of the propeller 4, and when the lowest point of the stern fin 10 is located below the height of the rotation axis SC of the propeller 4, the vertical distance H from the lowest point of the stern fin 10 to the height of the rotation axis SC of the propeller 4 may be greater than 30% of the diameter D of the propeller 4. The average Ea of the lengths from the leading edge 11 to the trailing edge 12 of the skeg 10 in the fore-and-aft direction of the hull 2 may also be greater than 50% of the diameter D of the propeller 4.
In the above embodiment, the leading edge 11 of the skeg 10 is located above the trailing edge 12, but the present invention is not limited thereto, and the leading edge 11 and the trailing edge 12 may have the same height. That is, the angle θ 1 of the chord line L2 of the stern fin 10 with respect to the horizontal plane may be 0 °.
In the above embodiment, the leading edge 11 extends while being inclined rearward by a predetermined angle (retreating angle) θ 2 with respect to the direction perpendicular to the center line CL of the hull 2, but the present invention is not limited thereto, and the leading edge 11 may extend in the direction perpendicular to the center line CL of the hull 2. In the above embodiment, the trailing edge 12 extends perpendicularly to the center line CL of the hull 2, but the present invention is not limited thereto, and the trailing edge 12 may extend obliquely forward or rearward by a predetermined angle with respect to the direction perpendicular to the center line CL of the hull 2. The shapes of the front edge 11 and the rear edge 12 may not be linear when viewed in plan. For example, the leading edge 11 and the trailing edge 12 may have curved shapes in plan view, and the straight portion extending from the hull 2 may be bent one or more times in the forward or rearward direction.
In addition, in the embodiment, the skeg 10 horizontally projects from the side surface of the hull 2, but the skeg 10 may also extend obliquely upward or downward as being distant from the side surface of the hull 2.
Further, fins other than the tail fin of the present invention may be provided on the stern portion.
In the above embodiment, the example in which the tail fin 10 is mounted on a single-shaft ship has been described, but the tail fin of the present invention can be applied to a multi-shaft ship. For example, the skegs may also be mounted on a twin shaft ship. Fig. 6 shows a schematic view of the stern portion 3 of the ship 1B as a biaxial ship as viewed from the rear. In fig. 6, substantially the same components as those in the above-described embodiment are denoted by the same reference numerals, and redundant description thereof is omitted. As shown in fig. 6, the hull 2 of the ship 1B has a pair of tail fin portions 8 projecting downward. The pair of fin portions 8 are separated in the lateral direction of the hull 2 and are positioned symmetrically with respect to the center line CL of the hull 2. Each tail fin portion 8 is provided with a propeller, not shown, which rotates about the rotation axis SC, as in the above-described embodiment. Similarly to the embodiment, a stern fin 10 is mounted on each of the right and left side surfaces of each of the tail fins 8. According to the ship 1B of the twin-shaft ship shown in fig. 6, the same effects as those of the ship 1A of the single-shaft ship shown in the above embodiment can be obtained.
In the ship 1B shown in fig. 6, two stern fins 10 are attached to each stern fin 8, but the stern fins 10 may be provided only on the center side of the hull 2 of each stern fin 8, or may be provided only on the outer side of the hull 2 of each stern fin 8. In these cases, the same effects as those of the above-described embodiment can be obtained.
Description of the reference symbols
1A, 1B: a vessel; 2: a hull; 3: a stern part; 4: a propeller; 10: a stern fin; 11: a leading edge; 12: a trailing edge; 14: an upper surface; 15: a lower surface.
Claims (6)
1. A stern fin which is provided with a propeller and is mounted on a side surface of a stern of a ship having a planned speed of ship with a Froude number of 0.17 or more,
the stern fin is located on the forward side of the propeller in the traveling direction of the ship and at a position near the height of the rotation axis of the propeller,
a center line obtained by sequentially joining midpoints of upper and lower surfaces of the stern fin in a cross-sectional shape of the stern fin perpendicular to a direction in which the stern fin projects from a side surface of the stern portion projects downward, a leading edge of the stern fin is located above a trailing edge,
in the projecting direction, a maximum projecting length of the stern fin from a side surface of the stern portion is 2% or more and 15% or less of a diameter of the propeller.
2. The skeg of claim 1 wherein said cross-sectional shape of said skeg is an airfoil.
3. The skeg of claim 1 or 2 wherein the trailing edge of the skeg is located further to the rear side in the direction of travel of the ship than a position 2 times the diameter of the propeller away from the front side in the direction of travel of the ship from the propeller.
4. The skeg of claim 1 or 2 wherein the average of the length from the leading edge to the trailing edge of the skeg in the fore-aft direction of the vessel is 50% or less of the diameter of the propeller.
5. The skeg of claim 3 wherein the average of the length from the leading edge to the trailing edge of the skeg in the fore-aft direction of the vessel is 50% or less of the diameter of the propeller.
6. A ship having the tail fin according to any one of claims 1 to 5.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017224660 | 2017-11-22 | ||
| JP2017-224660 | 2017-11-22 | ||
| JP2018-093850 | 2018-05-15 | ||
| JP2018093850A JP6951291B2 (en) | 2017-11-22 | 2018-05-15 | Stern fins and ships with them |
| PCT/JP2018/042513 WO2019102945A1 (en) | 2017-11-22 | 2018-11-16 | Stern fin and ship provided with same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110770117A CN110770117A (en) | 2020-02-07 |
| CN110770117B true CN110770117B (en) | 2022-04-05 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880039075.7A Active CN110770117B (en) | 2017-11-22 | 2018-11-16 | Tail fin and ship with same |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN110770117B (en) |
| WO (1) | WO2019102945A1 (en) |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62283096A (en) * | 1986-05-30 | 1987-12-08 | Ishikawajima Harima Heavy Ind Co Ltd | Stern stream adjusting complex fin system |
| JP2623895B2 (en) * | 1990-03-30 | 1997-06-25 | 石川島播磨重工業株式会社 | Stern viscous drag reduction device |
| JP3840454B2 (en) * | 2002-05-15 | 2006-11-01 | 株式会社新来島どっく | Asymmetric stern fin structure |
| JP4380975B2 (en) * | 2002-09-24 | 2009-12-09 | 三菱重工業株式会社 | Ship |
| KR100619302B1 (en) * | 2005-04-26 | 2006-09-06 | 현대중공업 주식회사 | The thrust fin for ships |
| JP2008260445A (en) * | 2007-04-13 | 2008-10-30 | Oshima Shipbuilding Co Ltd | Vessel |
| JP4938056B2 (en) * | 2008-07-22 | 2012-05-23 | 株式会社新来島どっく | Stern wave interference fin |
| JP4909380B2 (en) * | 2009-06-16 | 2012-04-04 | 三菱重工業株式会社 | Ship |
| JP5372977B2 (en) * | 2011-01-31 | 2013-12-18 | 株式会社新来島どっく | Composite fin |
| CN202175163U (en) * | 2011-07-19 | 2012-03-28 | 上海外高桥造船海洋工程设计有限公司 | Energy-saving device at tail part of ship |
| CN102381463B (en) * | 2011-08-17 | 2013-11-27 | 上海船舶研究设计院 | Reaction fin in front of propeller |
| CN103387037B (en) * | 2012-05-11 | 2015-12-09 | ***际造船股份有限公司 | The asymmetric Y-shaped fin swing device of boats and ships |
| KR20130128112A (en) * | 2012-05-16 | 2013-11-26 | 한국해양과학기술원 | Energy saving stern-fin with pre-swirl effect and hydro-foil section |
| CN203306217U (en) * | 2013-05-10 | 2013-11-27 | 武汉理工大学 | Propeller front water power energy-saving device used for full transport ship |
-
2018
- 2018-11-16 WO PCT/JP2018/042513 patent/WO2019102945A1/en active Application Filing
- 2018-11-16 CN CN201880039075.7A patent/CN110770117B/en active Active
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| Publication number | Publication date |
|---|---|
| WO2019102945A1 (en) | 2019-05-31 |
| CN110770117A (en) | 2020-02-07 |
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