JP2017222227A - Twin skeg ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of disturbance in a flow near a rear end part of a skeg thereby improving propulsion performance.SOLUTION: A twin skeg ship 1A comprising: a hull 1a; skegs 2A, in a pair, which are provided on a stern hull 3 of the hull 1a at an interval; propeller shafts 8 which are supported by the respective skegs 2A in the pair and project from the skegs 2A toward a stern 1b side; and propeller s10 which are fixed to the propeller shafts 8 on the stern 1b side with respect to the skegs 2A. Each skeg 2A comprises: lateral faces, in a pair, which respectively continuously extend toward the stern 1b side and are connected to each other at ends on the stern 1b side, on both sides of a ship width direction; and upper rectification parts 20A which are at least a part of portions above the propeller shafts 8, and which are so formed as to gradually extend to the ship width direction outer side as a center line of the pair of lateral faces approaches the stern 1b side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a twin skeg ship in which a pair of left and right skegs provided on the bottom of a stern are respectively provided with a propeller shaft.

  There is known a twin-skeg ship in which a pair of left and right skegs are provided on the stern bottom to form a tunnel-shaped bottom bottom recess between the left and right skegs, and a propeller shaft is provided on each of the pair of left and right skegs.

In such a twin-skeg ship, various proposals have been made to improve the propulsion performance.
For example, Patent Document 1 discloses a configuration in which guide portions for guiding a vertical vortex generated on the inner side in the ship width direction of each skeg to the inner side in the ship width direction are provided on the inner side surfaces in the ship width direction of the pair of left and right skegs. . According to such a configuration, the hull resistance due to the vortex resistance is reduced by canceling or weakening the pair of vertical vortices generated on the inner side in the ship width direction of the pair of left and right skeg portions.

JP 2012-17017 A

In a twin-skeg ship as described in Patent Document 1, the width dimension in the ship width direction of each skeg is gradually reduced toward the rear end of the propulsion direction. Therefore, in the vicinity of the rear end portion of each skeg, the flow along the inner side surface in the ship width direction of the skeg and the flow along the outer side surface in the ship width direction of the skeg merge.
On the other hand, on the inner side in the ship width direction of the skeg, an outward flow toward the outer side in the ship width direction occurs along the inner surface of the skeg. Further, on the outer side in the ship width direction of the skeg, an inward flow toward the inner side in the width direction of the ship occurs along the outer surface of the skeg.
In such a twin-skeg ship, an upward flow is generated in the diagonally upward direction toward the rear in accordance with the shape of the bottom of the ship that gradually inclines upward toward the rear in the propulsion direction inside the pair of left and right skegs. In other words, the outward flow of the skeg in the ship width direction inside has a higher flow velocity than the inward flow of the ship width direction outside due to this upward flow. Therefore, in the vicinity of the rear end of the skeg, separation may occur in the outward flow inside the skeg in the ship width direction. When separation occurs in the outward flow in the width direction of the skeg in this way, the outward flow in the width direction of the skeg collides with the inward flow in the width direction of the skeg, Disturbances occur in the flow of seawater near the rear end of the skeg. When the flow in the vicinity of the rear end of the skeg is disturbed in this way, the pre-swirl of the water flow on the upstream side of the propeller becomes insufficient, and the propulsion efficiency of the propeller may be reduced.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a twin-skeg ship capable of suppressing the turbulence in the flow in the vicinity of the rear end of the skeg and improving the propulsion performance.

The present invention employs the following means in order to solve the above problems.
According to the first aspect of the present invention, the twin skeg ship is supported by the hull, the pair of skegs provided at the stern portion of the hull with a space in the width direction of the hull, and the pair of skegs, respectively. A propeller shaft projecting from the stern side to the stern side, and a propeller fixed to the propeller shaft at the stern side from the skegg, and the pair of skegs are respectively continuous toward the stern side on both sides in the width direction of the stern. And at least part of the pair of side surfaces connected to each other at the stern end and the portion above the propeller shaft, the center line of the pair of side surfaces gradually increases toward the stern side. And an upper rectification portion formed to extend outward in the ship width direction.
With this configuration, in each skeg, the outer flow in the ship width direction and the inner flow in the ship width direction are directed outward in the ship width direction. Therefore, it is possible to suppress the occurrence of separation near the rear end portion above the propeller shaft in the skeg, or the turbulence caused by the collision of the flow outside the skeg in the ship width direction and the flow inside the ship width. . Furthermore, since it can suppress that a flow is disturb | confused, the pre-turn in the upstream of a propeller can fully be performed.

According to the second aspect of the present invention, in the twin skeg ship, the upper rectifying part in the first aspect may be configured such that the rear end part in the stern direction of the skeg is curved outward in the ship width direction. Good.
By configuring in this way, water flowing in the stern direction along each skeg can be smoothly moved outward in the width direction at the rear end of the skeg by the upper rectification unit formed on the upper side of the propeller shaft. It can flow.

According to a third aspect of the present invention, in the twin skegging ship, in the first or second aspect, the upper rectification unit is above the propeller shaft of the skeg and below the upper end position of the swivel range of the propeller. You may make it form in this.
By comprising in this way, disturbance which a disorder | damage | failure is suppressed by the upper rectification | straightening part, and the flow which goes to a ship width direction outer side is supplied to a propeller efficiently.

According to a fourth aspect of the present invention, in the twin skeg ship according to any one of the first to third aspects, the upper rectification unit is provided on the side surface on the outer side in the ship width direction of the skeg, on the inner side in the ship width direction. You may make it have the concave curved surface which dents toward.
By comprising in this way, the flow outside a ship width direction of a skeg can be smoothly guide | induced to the ship width direction outward by a concave curved surface.

According to a fifth aspect of the present invention, in the twin skeg ship according to any one of the first to fourth aspects, the pair of skegs is at least a part of a portion below the propeller shaft, You may make it further provide the lower rectification | straightening part formed so that the centerline of a pair of said side surface may extend toward inner side in a ship width direction gradually as it goes to the stern side.
With such a configuration, in each skeg, the flow on the outer side in the ship width direction and the flow on the inner side in the ship width direction are both inward in the ship width direction. Therefore, it is possible to prevent the flow from being disturbed due to separation near the rear end below the prop shaft of the skeg, or the collision of the flow outside the skeg in the ship width direction and the flow inside the ship width. it can. Furthermore, since it can suppress that a flow is disturb | confused, the pre-turn in the upstream of a propeller can fully be performed.

According to a sixth aspect of the present invention, in the fifth aspect of the twin skeg ship, the lower rectifying portion is configured such that the rear end portion in the stern direction of the skeg is curved inward in the ship width direction. Also good.
With this configuration, water flowing in the stern direction along each skeg is smoothly moved toward the inner side in the width direction at the rear end of the skeg by the lower rectifier formed on the lower side of the propeller shaft. Can be shed.

  According to the twin skeg ship, it is possible to suppress the turbulence in the flow in the vicinity of the rear end of the skeg and improve the propulsion performance.

It is the right view which looked at the stern part of the twin skeg ship in 1st embodiment of this invention from the starboard side. It is the rear view which looked at the stern part of the said twin skeg ship from back. It is a plane sectional view which shows the shape of the skeg provided in the stern part of the said twin skeg ship, and is D4-D4 arrow sectional drawing of FIG. It is the right view which looked at the stern part of the twin skeg ship in 2nd embodiment of this invention from the starboard side. It is the rear view which looked at the stern part of the said twin skeg ship from back. It is a plane sectional view which shows the shape of the skeg provided in the stern part of the said twin skeg ship, and is D5-D5 arrow sectional drawing of FIG.

Hereinafter, a twin-skeg ship according to an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a right side view of a stern portion of a twin-skeg ship according to the first embodiment of the present invention as seen from the starboard side. FIG. 2 is a rear view of the stern portion of the twin-skeg ship as viewed from the rear. FIG. 3 is a plan sectional view showing the shape of the skeg provided in the stern portion of the twin skeg ship. Here, lines D1, D2, and D3 in FIG. 2 indicate the cross-sectional shape of the skeg at positions D1, D2, and D3 in FIG.
As shown in FIGS. 1 and 2, the twin skeg ship 1 </ b> A in this embodiment includes a hull 1 a, a skeg 2 </ b> A, a propeller shaft 8, and a propeller 10.

  The hull 1a includes a stern hull (stern part) 3 forming the stern 1b. The stern hull 3 has an inclined surface 4s that is gradually inclined upward toward the stern 1b from the bow (not shown) on the bottom 4 thereof. The ship bottom 4 of the stern hull 3 is formed such that the width dimension in the ship width direction gradually decreases from the bow (not shown) side toward the stern 1b side.

  As shown in FIG. 2, the skeg 2 </ b> A is provided on the inclined surface 4 s of the bottom 4 with a pair of left and right symmetrically across the center C in the ship width direction with an interval in the ship width direction. Each of the pair of left and right skegs 2A is provided so as to protrude rearward from the inclined surface 4s. The pair of left and right skegs 2A are provided so as to gradually extend outward in the ship width direction from the root portion 2c on the inclined surface 4s side of the bottom 4 of the stern hull 3 toward the lower end portion 2d.

  A pair of left and right skegs 2A and an inclined surface 4s of the bottom 4 are formed below the stern hull 3 so as to form a bottom recess 5 surrounded by the pair of left and right skegs 2A and the inclined surface 4s of the bottom 4 of the stern.

  At the rear end portion of each skeg 2A, a cylindrical boshing 6 protruding rearward is provided.

  The propeller shaft 8 is supported by each skeg 2A. One end of the propeller shaft 8 is connected to the main engine (not shown) in the hull 1a, and the other end 8b protrudes from the stern hull 3 through the bossing 6 to the rear of the skeg 2A.

The propeller 10 is integrally fixed to the other end 8b of the propeller shaft 8 protruding rearward of the skeg 2A at the rear end of each of the pair of left and right skegs 2A. Each propeller 10 is connected to a main engine (not shown) provided in the stern hull 3 via a propeller shaft 8.
Such a propeller 10 rotates in a predetermined direction when the propeller shaft 8 is driven to rotate around its central axis by a main engine (not shown) provided in the stern hull 3, and exhibits the propulsive force of the twin-skeg ship 1A. To do.
In this embodiment, the rotation direction of the propeller 10 provided at each of the rear end portions of the pair of left and right skegs 2A is an inner rotation R1, R2 that rotates from the outer side in the ship width direction toward the center C in the ship width direction at the upper part of the propeller 10. And

  As shown in FIG. 3, each skeg 2 </ b> A has side surfaces 2 s and 2 t that continuously extend toward the rear (left side in FIG. 3) on both sides in the ship width direction. The skeg 2A is formed so that its thickness in the width direction gradually decreases toward the stern 1b, and the side surfaces 2s and 2t on both sides in the width direction merge at the rear end 2b of the skeg 2A and are connected to each other. ing.

Each of the skegs 2A is at least a part of the portion above the propeller shaft 8, and the center lines E1 of the side surfaces 2s, 2t on both sides in the ship width direction are the center of the root portion 2c of the skeg 2A and the center of the propeller shaft 8. Is offset outward in the ship width direction with respect to the virtual plane K connecting the two. The offset dimension of the center line E1 of the side surfaces 2s and 2t of the skeg 2C toward the outside in the ship width direction gradually increases toward the rear.
Therefore, the side surface 2s outside the ship width direction of the skeg 2A is formed so as to extend outward in the ship width direction toward the rear end portion 2b between the propeller shaft 8 and the root portion 2c in a state in plan view. Yes. In this embodiment, a concave curved surface 21 that is recessed inward in the ship width direction is formed on the side surface 2s of the skeg 2A at a portion above the propeller shaft 8.
Further, the side surface 2t on the inner side in the ship width direction of the skeg 2A is formed so as to extend outward in the ship width direction between the propeller shaft 8 and the root portion 2c toward the rear end portion 2b in a plan view. ing. In this embodiment, a convex curved surface 22 bulging inward in the ship width direction is formed on the side surface 2t of the skeg 2A at a portion above the propeller shaft 8.
In this manner, the upper rectification portion 20A that is curved and extends toward the outer side in the ship width direction is formed between the propeller shaft 8 and the root portion 2c at the rear end portion 2b of the skeg 2A.

The twin-skeg ship 1A provided with such a pair of left and right skegs 2A has a slanted surface 4s on the bottom 4 of the pair of left and right skegs 2A and 2A on the inner side in the ship width direction so as to be inclined obliquely upward. An upward flow is generated.
In the portion of each skeg 2A above the propeller shaft 8, in the vicinity of the rear end portion 2b where the upper rectifying portion 20A is formed, the flow F1 inside the ship width direction of the skeg 2A and the outside of the skeg 2A outside the ship width direction Flow F2 joins. The flow F1 on the inner side in the ship width direction of the skeg 2A becomes an outward flow F1 toward the outer side in the ship width direction along the concave curved surface 21 of the side surface 2t of the skeg 2A bulging inward in the ship width direction. Further, the flow F2 on the outer side in the ship width direction of the skeg 2A becomes an outward flow F2 toward the outer side in the ship width direction along the convex curved surface 22 of the side surface 2s of the skeg 2A recessed inward in the ship width direction.
In this way, in the vicinity of the rear end 2b of the skeg 2A, the outward flows F1 and F2 toward the outside in the width direction of the ship join together, so that separation is unlikely to occur behind the rear end 2b of the skeg 2A. Become.

  In the first embodiment, the case where the upper rectifying portion 20A is formed between the propeller shaft 8 and the root portion 2c has been described. However, the upper rectifying unit 20A may be formed at least in a region above the propeller shaft 8 and below the upper end position Pt of the turning range of the propeller 10 in the vertical direction. As described above, when the upper rectification unit 20A is formed at least above the propeller shaft 8 of the skeg 2A and below the upper end position Pt of the turning range of the propeller 10, the ship width of the skeg 2A is increased by the upper rectification unit 20A. A smooth flow in which the flow F1 on the inner side in the direction and the flow F2 on the outer side in the ship width direction are prevented from colliding can be efficiently supplied to the propeller 10.

  In the skeg 2A in the first embodiment, the center line E1 of the side surfaces 2s and 2t is outside the widthwise direction with respect to the virtual plane K only in the region close to the propeller 10 among the regions between the propeller shaft 8 and the root portion 2c. The case of offsetting to has been described. However, the skeg 2A may be configured such that the center line E1 of the side surfaces 2s and 2t is offset from the virtual plane K outward in the ship width direction in the entire region between the propeller shaft 8 and the root portion 2c.

  Further, the upper rectifying unit 20A has a length L in the front-rear direction of the hull 1a within a range of 1/30 of the total length of the hull 1a from the rear end 2b of the skeg 2A toward the bow (not shown). Can do. Furthermore, the length L of the upper rectifying unit 20A can be formed within a range of 1/50 or less of the total length of the hull 1a from the rear end 2b of the skeg 2A toward the bow side. Furthermore, the length L of the upper rectifying unit 20A can be formed within a range of 1/200 of the total length of the hull 1a from the rear end 2b of the skeg 2A toward the bow.

  Therefore, according to the twin skeg ship of the first embodiment described above, the upper rectifying unit 20A formed above the propeller shaft 8 in the skeg 2A has the center line E1 of the pair of side surfaces 2s and 2t of the skeg 2A. It gradually extends outward in the ship width direction toward 1b. Thereby, in each skeg 2A, the flow F1 inside the ship width direction and the flow F2 outside the ship width direction are both outward in the ship width direction. Therefore, in the vicinity of the rear end 2b of the skeg 2A above the propeller shaft 8, the flow F1 inside the ship width direction of the skeg 2A collides with the flow F2 outside the ship width direction, and the flow is disturbed. Can be suppressed. As a result, the flow on the upstream side of the propeller 10 is smoothly directed to the outside in the ship width direction by the upper rectifying unit 20A, and is rotated inward R1, R2 from the outside in the ship width direction toward the center C in the ship width in the upper part. Preliminary turning with respect to the propeller 10 can be sufficiently performed, and the propulsion performance by the propeller 10 can be improved.

  Furthermore, as for upper rectification | straightening part 20A, the rear-end part 2b of the stern direction of skeg 2A is curving toward the ship width direction outer side. Therefore, the flows F1 and F2 heading in the stern direction along each skeg 2A are efficiently directed outward in the width direction at the rear end portion 2b of the skeg 2A by the upper rectifying portion 20A formed on the upper side of the propeller shaft 8. Change direction. As a result, the flow F1 on the inner side in the ship width direction of the skeg 2A on the upper side of the propeller shaft 8 of the skeg 2A and the flow F2 on the outer side in the width direction of the skeg 2A can be efficiently suppressed. it can.

  Further, the upper rectification unit 20A has a concave curved surface 21 that is recessed toward the inner side in the ship width direction on the side surface 2s on the outer side in the ship width direction of the skeg 2A. Therefore, the upper rectification unit 20A can efficiently guide the flow F2 outside the ship width direction of the skeg 2A outward in the ship width direction by the concave curved surface 21 formed on the side surface 2s outside the ship width direction in the skeg 2A. .

(Second embodiment)
Next, a second embodiment of the present invention will be described. This second embodiment is different from the first embodiment only in that the lower rectification unit 20C is provided in the skeg, and therefore, the same parts as those in the first embodiment are denoted by the same reference numerals and redundant description is omitted.
FIG. 4 is a right side view of the stern portion of the twin-skeg ship according to the first embodiment of the present invention viewed from the starboard side. FIG. 5 is a rear view of the stern portion of the twin-skeg ship as viewed from the rear. FIG. 6 is a plan sectional view showing the shape of the skeg provided in the stern portion of the twin skeg ship, and is a sectional view taken along arrow D5-D5 in FIG. Here, lines D1, D2, and D3 in FIG. 5 indicate the cross-sectional shape of the skeg at positions D1, D2, and D3 in FIG.

  As shown in FIGS. 4 and 5, the twin skeg ship 1 </ b> B in this embodiment includes a hull 1 a, a skeg 2 </ b> C, a propeller shaft 8, and a propeller 10.

  As shown in FIG. 6, each of the pair of left and right skegs 2 </ b> C has side surfaces 2 u and 2 v that continuously extend toward the rear (leftward in FIG. 6) on both sides in the ship width direction. The skeg 2C is formed such that the thickness in the ship width direction gradually decreases rearward (leftward in FIG. 6), and the side surfaces 2u and 2v on both sides in the ship width direction join at the rear end portion 2b of the skeg 2C. And connected to each other.

As in the first embodiment, each of the skegs 2C is at least part of the portion above the propeller shaft 8 and is centered on the center lines E1 of the side surfaces 2u, 2v on both sides in the ship width direction, as shown in FIG. However, it is offset outward in the ship width direction with respect to a virtual plane K connecting the root 2c of the skeg 2C and the center of the propeller shaft 8. The offset dimension of the side surfaces 2u, 2v of the skeg 2C toward the outside in the ship width direction gradually increases toward the stern 1b side. In other words, the skeg 2C is formed between the propeller shaft 8 and the root portion 2c so that the lateral side 2u on the outer side in the ship width direction extends outward in the ship width direction toward the rear end portion 2b in a plan view. Has been. Also in the second embodiment, the side surface 2u of the skeg 2C is formed with a concave curved surface 21 that is recessed inward in the ship width direction at a portion above the propeller shaft 8. Further, the skeg 2C is formed between the propeller shaft 8 and the root portion 2c such that the side surface 2v on the inner side in the ship width direction extends outward in the ship width direction toward the rear end portion 2b in a plan view. ing. In this embodiment, on the side surface 2v of the skeg 2C, a convex curved surface 22 bulging inward in the ship width direction is formed in a portion above the propeller shaft 8.
In this manner, an upper rectifying portion 20A that extends curvedly outward in the ship width direction is formed between the propeller shaft 8 and the root portion 2c at the rear end portion 2b of the skeg 2C.

  As shown in FIG. 5, each of the skegs 2C is at least a part of the portion below the propeller shaft 8, and the center lines E2 of the side surfaces 2u and 2v on both sides in the ship width direction are the tip portions 2d of the skeg 2C. And an imaginary plane K connecting the center of the propeller shaft 8 and offset inward in the ship width direction. The offset dimension toward the inner side in the ship width direction of the center line E2 of the side surfaces 2u and 2v of the skeg 2C gradually increases toward the rear.

The side surface 2u outside the ship width direction of the skeg 2C is formed to extend inward in the ship width direction toward the rear end portion 2b between the propeller shaft 8 and the front end portion 2d in a plan view. In this embodiment, a convex curved surface 23 bulging outward in the ship width direction is formed on the side surface 2u of the skeg 2C at a portion below the propeller shaft 8.
Further, the side surface 2v on the inner side in the ship width direction of the skeg 2C is formed so as to extend inward in the ship width direction toward the rear end portion 2b between the propeller shaft 8 and the front end portion 2d in a plan view. . In this embodiment, on the side surface 2v of the skeg 2C, a concave curved surface 24 that is recessed outward in the ship width direction is formed in a portion below the propeller shaft 8.
Thus, a lower rectification portion 20C that is curved and extends inward in the ship width direction is formed between the propeller shaft 8 and the front end portion 2d at the rear end portion 2b of the skeg 2C.

The twin-skeg ship 1B having such a pair of left and right skegs 2C has an upward flow that is inclined obliquely upward toward the rear by the inclined surface 4s in the bottom recess 5 inside the ship width direction of the pair of left and right skegs 2C and 2C. Occurs.
Similarly to the first embodiment, in the portion above the propeller shaft 8 of each skeg 2C, in the vicinity of the rear end portion 2b of the upper rectifying unit 20A, the flow F3 inside the ship width direction of the skeg 2C and the skeg 2C The flow F4 on the outer side in the ship width direction merges. The flow F3 on the inner side in the ship width direction of the skeg 2C becomes an outward flow F3 toward the outer side in the ship width direction along the convex curved surface 22 of the side surface 2v of the skeg 2C bulged in the inner side in the ship width direction. Further, the flow F4 on the outer side in the ship width direction of the skeg 2C becomes an outward flow F4 toward the outer side in the ship width direction along the concave curved surface 21 of the side surface 2u of the skeg 2C recessed inward in the ship width direction.
In the vicinity of the rear end portion 2b of the skeg 2C in which the upper rectifying portion 20A is formed in this way, the outward flows F3 and F4 toward the outer side in the width direction of the vessel join together, so the rear end portion 2b of the skeg 2C. Peeling is less likely to occur behind.

Further, as shown in FIG. 6, in the portion below the propeller shaft 8 of each skeg 2C, in the vicinity of the rear end portion 2b of the lower rectifying portion 20C, the flow F3 inside the ship width direction of the skeg 2C and the skeg 2C The flow F3 on the outer side in the ship width direction merges. The flow F3 on the inner side in the ship width direction of the skeg 2C becomes an inward flow F3 toward the inner side in the ship width direction along the concave curved surface 24 of the side surface 2v of the skeg 2C that is recessed outward in the ship width direction. Further, the flow F4 on the outer side in the ship width direction of the skeg 2C becomes an inward flow F4 toward the inner side in the ship width direction along the convex curved surface 23 of the side surface 2u of the skeg 2C bulging outward in the ship width direction.
Thus, in the vicinity of the rear end 2b of the skeg 2C in which the lower rectification unit 20C is formed, the inward flows F3 and F4 that are directed inward in the width direction of the ship join together, so the rear end of the skeg 2C Peeling hardly occurs behind 2b.

Here, in this second embodiment, the case where the upper rectification portion 20A is formed between the propeller shaft 8 and the root portion 2c, and the lower rectification portion 20C is formed between the propeller shaft 8 and the tip portion 2d. explained. However, the upper rectification unit 20A may be formed in a region above the propeller shaft 8 and below the upper end position Pt of the turning range of the propeller 10 in the vertical direction. Further, the lower rectification unit 20C may be formed in a region below the propeller shaft 8 and above the lower end position Pb of the turning range of the propeller 10 in the vertical direction.
When the upper rectification unit 20A is thus formed at least above the propeller shaft 8 of the skeg 2C and below the upper end position Pt of the turning range of the propeller 10, the ship width of the skeg 2C is increased by the upper rectification unit 20A. A smooth flow in which the flow F3 on the inner side in the direction and the flow F4 on the outer side in the ship width direction are prevented from colliding can be efficiently supplied to the propeller 10. Similarly, when the lower rectification unit 20C is formed at least below the propeller shaft 8 of the skeg 2C and above the lower end position Pb of the turning range of the propeller 10, the ship width of the skeg 2C is reduced by the lower rectification unit 20C. A smooth flow in which the flow F3 on the inner side in the direction and the flow F4 on the outer side in the ship width direction are prevented from colliding can be efficiently supplied to the propeller 10.

  Further, in the upper rectification unit 20A and the lower rectification unit 20C, the length L in the front-rear direction of the hull 1a is within 1/30 of the total length of the hull 1a from the rear end 2b of the skeg 2C toward the bow (not shown). Range. Furthermore, the upper rectification unit 20A and the lower rectification unit 20C can be formed within a range within 1/50 of the total length of the hull 1a from the rear end 2b of the skeg 2C toward the bow. Furthermore, the upper rectification unit 20A and the lower rectification unit 20C can be formed within a range within 1/200 of the total length of the hull 1a from the rear end 2b of the skeg 2C toward the bow.

  Therefore, according to the twin skeg ship of the second embodiment described above, the flow F3 on the inner side in the ship width is caused by the upper rectification unit 20A formed above the propeller shaft 8 in the skeg 2C, as in the first embodiment. And the flow F4 on the outer side in the ship width direction are both outward in the ship width direction. Therefore, in the vicinity of the rear end portion 2b of the skeg 2C above the propeller shaft 8, the flow F3 on the inner side in the ship width direction of the skeg 2C and the flow F4 on the outer side in the ship width direction are prevented from colliding with each other. Can do. As a result, the upper flow on the upstream side of the propeller 10 is smoothly directed outward in the width direction of the propeller, and the pre-turning with respect to the propeller 10 rotating from the outer side in the width direction toward the center C side in the width direction is sufficiently performed in the upper part. The propulsion performance by the propeller 10 can be improved.

  Further, the lower rectification portion 20C formed below the propeller shaft 8 in the skeg 2C is gradually directed inward in the ship width direction as the center line E2 of the pair of side surfaces 2u and 2v of the skeg 2C moves toward the stern 1b. It extends. Thereby, in each skeg 2C, the flow F3 inside the ship width direction and the flow F4 outside the ship width direction are both inward in the ship width direction. Therefore, in the vicinity of the rear end portion 2b of the skeg 2C below the propeller shaft 8, the flow F3 inside the ship width direction of the skeg 2C collides with the flow F4 outside the ship width direction and the flow is disturbed. Can be suppressed. As a result, the downward flow on the upstream side of the propeller 10 is smoothly directed toward the inner side in the ship width direction, and the preliminary turning with respect to the propeller 10 that rotates from the center C side in the width direction toward the outer side in the ship width is sufficiently performed at the lower part. The propulsion performance by the propeller 10 can be improved.

  Further, in the lower rectification unit 20C, the stern end rear end 2b of the skeg 2C is curved inward in the ship width direction. With this configuration, the flows F3 and F4 heading in the stern direction along each skeg 2C are caused to flow at the rear end 2b of the skeg 2C by the lower rectification unit 20C formed on the lower side of the propeller shaft 8. Efficiently change the direction of flow toward the outside of the direction. Therefore, in the vicinity of the rear end portion 2b below the propeller shaft 8 of the skeg 2C, the flow F3 on the inner side in the ship width direction of the skeg 2C and the flow F4 on the outer side in the ship width direction collide with each other to efficiently disturb the flow. It can be suppressed well.

(Other variations)
The present invention is not limited to the above-described embodiments, and includes various modifications made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific shapes, configurations, and the like given in the embodiment are merely examples, and can be changed as appropriate.
For example, the pair of left and right skegs 2A and 2C each have a shape extending obliquely downward from the inclined surface 4s of the bottom 4 of the stern hull 3 toward the outside in the width direction of the stern, but is not limited thereto. The pair of left and right skegs 2 </ b> A and 2 </ b> C may have a shape extending parallel to each other from the inclined surface 4 s of the bottom 4 of the stern hull 3 toward the vertically lower side.

1A, 1B Twin Skeg Ship 1a Hull 1b Stern 2A, 2C Skeg 2b Rear End 2c Root 2d Tip 2s Side 2t Side 2u Side 2v Side 3 Stern Hull (Stern)
4 Ship bottom 4s Inclined surface 5 Ship bottom recess 6 Boshing 8 Propeller shaft 8b Other end 10 Propeller 20A Upper rectification unit 20C Lower rectification unit 21 Concave surface 22 Convex surface 23 Convex surface 24 Concave surface C Ship width direction center E1 Center line E2 Center line K Virtual plane Pb Lower end position Pt Upper end position R1 Inward R2 Inward

Claims (6)

The hull,
A pair of skegs provided in the stern portion of the hull with a gap in the width direction;
Propeller shafts that are respectively supported by a pair of the skegs and project from the skegs to the stern side;
A propeller fixed to the propeller shaft on the stern side of the skeg,
With
A pair of the skegs
A pair of side surfaces that continuously extend toward the stern side on both sides in the width direction of the stern and are connected to each other at the ends of the stern side;
An upper rectification part formed so that the center line of the pair of side surfaces gradually extends outward in the ship width direction toward the stern side in at least a part of the portion above the propeller shaft;
Twin skeg ship equipped with.   2. The twin-skeg ship according to claim 1, wherein a rear end portion of the upper rectifying unit in the stern direction of the skeg is curved outward in the ship width direction.   3. The twin skeg ship according to claim 1, wherein the upper rectifying unit is formed above the propeller shaft of the skeg and below an upper end position of a turning range of the propeller.   4. The twin-skeg ship according to claim 1, wherein the upper rectification unit has a concave curved surface that is recessed toward the inner side in the ship width direction on a side surface on the outer side in the ship width direction of the skeg.   The pair of skegs is at least part of a portion below the propeller shaft, and a center line of the pair of side surfaces is formed to gradually extend inward in the ship width direction toward the stern side. The twin skeg ship according to any one of claims 1 to 4, further comprising a lower rectification unit.   The twin skeg ship according to claim 5, wherein the lower rectification part has a rear end part in the stern direction of the skeg curved toward the inner side in the ship width direction.

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