JP7049144B2 - Stern fins and ships - Google Patents

Description

The present invention relates to a stern fin and a ship provided in a bilge on the stern side of a hull.

In a general ship, the width of the hull becomes maximum near the middle in the longitudinal direction, and gradually decreases so as to form an arc toward the stern side. When this vessel sails forward, seawater flows backward along the vessel side and bottom. Seawater flowing backward along the ship side is a downward flow on the stern side, and seawater flowing backward along the bottom of the ship is an upward flow on the stern side. Therefore, the intersection of this downward flow and the upward flow generates a bilge vortex separated from the stern. This bilge vortex passes above the rotating surface of the propeller and flows to the rear of the hull, but it is known that the slow seawater flow near the bilge vortex flows into the rotating surface of the propeller, improving the propeller propulsion efficiency. Has been done.

As a technique for allowing a slow seawater flow near a bilge vortex to flow into the rotating surface of a propeller, for example, there is one described in Patent Document 1 below. The ship described in Patent Document 1 is provided with bilge fins on both sides of the outer panel of the bilge portion rearward from the rear end of the hull parallel portion.

Japanese Unexamined Patent Publication No. 2008-260445

Although the above-mentioned bilge fin can guide the bilge vortex separated from the stern to the rotating surface of the propeller, the hull resistance increases due to the bilge fin itself. That is, there is a trade-off relationship between the increase in intrinsic resistance due to the bilge fin itself and the improvement in propulsion efficiency due to the induction control of the bilge vortex. Therefore, in order to achieve the improvement of propulsion efficiency by the induction control of the bilge vortex, it is necessary to reduce the size to reduce the intrinsic resistance of the bilge fin.

The present invention solves the above-mentioned problems, and an object of the present invention is to provide a stern fin and a ship that improve propulsion efficiency and suppress an increase in resistance.

The stern fin of the present invention for achieving the above object is a stern fin provided in a bilge of a hull with respect to a first angle with respect to a horizontal plane of a root portion attached to the hull and a horizontal plane of a tip portion separated from the hull. It is characterized in that it is different from the second angle.

Therefore, since the first angle of the root part attached to the hull and the second angle of the tip part are different, the bilge generated by the intersection of the water flow flowing backward along the ship side and the water flow flowing backward along the ship bottom. The vortex is properly guided to the rotating surface of the propeller by the stern fins having different angles at the root and the tip, which can improve the propulsion efficiency of the propeller and suppress the increase in size to reduce the propulsion resistance. The increase can be suppressed.

The stern fin of the present invention is characterized in that the second angle is set larger than the first angle.

Therefore, since the second angle of the tip portion is larger than the first angle of the root portion attached to the hull, the water flow away from the hull can be effectively guided to the rotating surface of the propeller.

In the stern fin of the present invention, the front end portion in the captain direction has a linear shape from the root portion to the tip portion, and the rear end portion in the captain direction has a curved shape or a bent shape from the root portion to the tip portion. It is characterized by making a stern.

Therefore, since the bilge vortex is formed integrally from the root portion to the tip portion, the bilge vortex can be effectively guided to the rotating surface of the propeller.

The stern fin of the present invention is characterized by having a first fin main body constituting the root portion and a second fin main body constituting the tip portion.

Therefore, since the first fin main body constituting the root portion and the second fin main body constituting the tip portion are separately configured, the manufacturing can be easily performed and the manufacturing cost can be reduced.

The stern fin of the present invention is characterized in that the first angle and the second angle differ in the range of 3 deg to 100 deg.

Therefore, since the difference between the first angle and the second angle is in the range of 3 deg to 100 deg, the bilge vortex can be effectively guided to the rotating surface of the propeller.

Further, the ship of the present invention is characterized by including a hull, a propeller arranged at the stern of the hull, a rudder arranged behind the propeller at the stern of the hull, and a stern fin. It is a thing.

Therefore, since the first angle of the base of the stern fin provided on the bilge of the hull and the second angle of the tip are different, the water flow flowing backward along the ship side and the water flow flowing backward along the ship bottom intersect. The resulting bilge vortex is properly guided to the rotating surface of the propeller by the stern fins with different angles at the root and tip, which can improve the propulsion efficiency of the propeller and suppress the increase in size. Therefore, the increase in propulsion resistance can be suppressed.

In the ship of the present invention, where the rotation diameter of the propeller is Dp, the stern fin is provided in a range of 0.5 Dp or more and 5.0 Dp or less from the rotation center of the rudder toward the bow. There is.

Therefore, since the stern fin is attached to an appropriate position in the captain's direction, the bilge vortex can be appropriately guided to the rotating surface of the propeller, and the propeller propulsion efficiency can be improved.

In the ship of the present invention, when the stern fin is provided in a range of 2.0 Dp or more and 5.0 Dp or less from the center of rotation of the rudder toward the bow, the stern fin has a negative pressure surface on the upper surface side in the ship height direction. It is characterized in that the lower surface side in the height direction of the ship is set to the positive pressure surface.

Therefore, when the stern fin is provided away from the rudder in the bow direction, the upper surface side of the stern fin is the negative pressure surface and the lower surface side is the positive pressure surface, so that the bilge vortex can be properly guided to the rotating surface of the propeller. can.

In the ship of the present invention, when the stern fin is provided in a range of 0.5 Dp or more and less than 2.0 Dp from the center of rotation of the rudder toward the bow, the stern fin is in the height direction of the root portion. The upper surface side is set to the positive pressure surface, the lower surface side in the ship height direction is set to the negative pressure surface, the upper surface side in the ship height direction of the tip is set to the negative pressure surface, and the lower surface side in the ship height direction is set to the positive pressure surface. It is characterized by that.

Therefore, when the stern fin is provided close to the rudder, the upper surface side of the root portion is set as the positive pressure surface and the lower surface side is set as the negative pressure surface, and the upper surface side of the tip portion is set as the negative pressure surface and the lower surface side is set as the positive pressure surface. , The bilge vortex can be properly guided to the rotating surface of the propeller.

In the ship of the present invention, assuming that the center of rotation of the propeller is PCL, the width of the ship is W, the radius of rotation of the propeller is R, and the center line in the width direction is CL, the stern fins are the center of rotation PCL and the center. The connecting line L1 connecting the position on the baseline of the ship bottom separated from the line CL by W / 4 in the beam width direction, the position above 1.1R in the ship height direction from the rotation center PCL, and the center line CL. It is characterized in that it is provided in the region between the connecting line L2 and the position on the baseline of the ship bottom separated from the ship by W / 2 in the width direction of the ship.

Therefore, since the stern fin is attached to an appropriate position in the width direction of the ship, the bilge vortex can be appropriately guided to the rotating surface of the propeller, and the propulsion efficiency of the propeller can be improved.

The ship of the present invention is characterized in that the mounting angle of the root portion with respect to the hull is set to 90 degrees.

Therefore, since the mounting angle of the root portion is set to 90 degrees, it is possible to suppress a decrease in the support rigidity of the stern fin.

The ship of the present invention is characterized in that the length of the stern fin in the direction away from the hull is set within a range of 1% or more and 15% or less of the rotation diameter Dp of the propeller.

Therefore, since the length of the stern fin is set to an appropriate length, the stern fin can be miniaturized, while the bilge vortex can be appropriately guided to the rotating surface of the propeller.

In the ship of the present invention, the hull is characterized in that the square coefficient is set to be larger than 0.75.

Therefore, in a hull where a bilge vortex is likely to occur, the bilge vortex can be appropriately guided to the rotating surface of the propeller, and the propeller propulsion efficiency can be improved.

According to the stern fin and the ship of the present invention, it is possible to improve the propulsion efficiency and suppress the increase in resistance.

FIG. 1 is a schematic side view of the ship of the first embodiment. FIG. 2 is a schematic bottom view of the ship of the first embodiment. FIG. 3 is a rear view showing the stern of the first embodiment. FIG. 4 is a perspective view showing the bilge fin of the first embodiment. FIG. 5 is a schematic diagram for explaining the twist angle of the bilge fin. FIG. 6 is a cross-sectional view of a front end portion and a rear end portion of the bilge fin showing the cross-sectional shape of the bilge fin. FIG. 7 is a graph showing the flow direction angle of the bilge fin. FIG. 8 is a schematic side view of the ship of the second embodiment. FIG. 9 is a perspective view showing the bilge fin of the second embodiment. FIG. 10 is a schematic side view of the ship of the third embodiment. FIG. 11 is a perspective view showing the bilge fin of the third embodiment.

Preferred embodiments of the stern fins and ships according to the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and when there are a plurality of embodiments, the present invention also includes a combination of the respective embodiments.

[First Embodiment]
1 is a schematic side view of the ship of the first embodiment, FIG. 2 is a schematic bottom view of the ship of the first embodiment, and FIG. 3 is a rear view showing the stern of the first embodiment.

The vessel of the first embodiment is a large commercial vessel, for example, a large oil tanker (VLCC, ULCC), an LNG carrier, an LPG carrier, a passenger ship (car ferry), or the like. That is, the ship of the first embodiment is applied to a ship having a square coefficient Cb larger than 0.75 (Cb> 0.75). The square coefficient is expressed by the ratio of the volume of the ship below the water line (drainage volume) to the length of the water line, the width of the water line, and the cube covered with draft.

In the ship of the first embodiment, as shown in FIGS. 1 to 3, the hull 10 has a bow 11, a stern 12, a bottom 13, a port 14 and a starboard 15. In the present embodiment, the hull length direction (front-back direction) is represented as the X direction, the ship width direction (width direction) is represented as the Y direction, and the ship height direction (vertical direction) is represented as the Z direction. Further, CL represents the center line in the width direction of the hull 10, WL represents the full draft waterline of the hull 10, PCL represents the rotation center line (rotation center) of the propeller, and RCL represents the rotation center line of the rudder. Represents (center of rotation).

The hull 10 has a maximum width near the middle portion in the captain direction X, gradually decreases in an arc shape toward the bow 11, and gradually decreases in an arc shape toward the stern 12. It has become. In the hull 10, the cross-sectional shape of the intermediate portion in the captain direction X is substantially rectangular, and the port 14 and starboard 15 are arcuate toward the stern 12. The arc-shaped portions of the port 14 and the starboard 15 are referred to as bilges 14a and 15a. The port bilge 14a and the starboard bilge 15b have an overhang portion 21 whose lower portion is cut off at the stern 12, and a propeller 22 and a rudder 23 are arranged below the overhang portion 21.

Although not shown, the hull 10 has an engine room partitioned inside the stern 12, and a main engine (for example, a diesel engine) is arranged in this engine room. In the main engine, the output shaft is arranged along the captain's direction X, the tip portion extends to the outside of the hull 10, and the propeller 22 is connected. The propeller 22 can rotate about the rotation center line PCL along the captain's direction X.

The hull 10 is provided with a rudder 23 at the lower part of the overhang portion 21 at the stern 12. The rudder 23 controls the traveling direction of the hull 10, and can rotate around the rotation center line RCL along the hull height direction Z.

The hull 10 is provided with bilge fins (stern fins) 24 and 25, respectively, on the port bilge 14a and the starboard bilge 15a. As the vessel sails forward, seawater flows backward along the bottom 13, port 14, and starboard 15. At this time, the seawater flowing backward along the port 14 and starboard 15 becomes a downward flow on the stern 12 side, and the seawater flowing backward along the ship bottom 13 becomes an upward flow on the stern 12 side. When the descending flow and the ascending flow intersect, a bilge vortex separated from the stern 12 is generated. The bilge fins 24 and 25 improve the propulsion efficiency of the propeller by flowing the bilge vortex into the rotating surface of the propeller 22, and have a symmetrical shape with respect to the center line CL.

Hereinafter, the bilge fins 24 and 25 in the ship of the first embodiment will be described in detail. 4 is a perspective view showing the bilge fin of the first embodiment, FIG. 5 is a schematic view for explaining a twist angle of the bilge fin, and FIG. 6 is a front end portion and a rear end portion of the bilge fin showing a cross-sectional shape of the bilge fin. The cross-sectional view and FIG. 7 are graphs showing the flow direction angle of the bilge fin.

As shown in FIGS. 4 to 6, the bilge fins 24 and 25 of the first embodiment have a first angle θ1 with respect to the horizontal plane of the root portion 31 attached to the hull 10 and a first angle θ1 with respect to the horizontal plane of the tip portion 32 separated from the hull 10. The two angles θ2 are different. In this case, the second angle θ2 is set larger than the first angle θ1. Here, the first angle θ1 and the second angle θ2 are the angles of the connecting lines connecting the center of the curved portion of the front end portion and the center of the curved portion of the rear end portion of the bilge fins 24 and 25 with respect to the horizon.

The bilge fins 24 and 25 have a wing shape along the captain direction X, the bilge fins 24 extend along the beam direction Y away from the port 14 of the hull 10, and the bilge fins 25 extend away from the starboard 15 of the hull 10. It extends along the width direction Y of the ship. Then, in the bilge fins 24 and 25, the rear end portion of the tip portion 32 separated from the hull 10 extends upward in the hull height direction Z with respect to the rear end portion of the root portion 31 attached to the hull 10. ..

As shown in FIGS. 1 and 3, assuming that the rotation diameter of the propeller 22 is Dp, the bilge fins 24 and 25 are at 0.5 Dp or more from the rotation center line RCL of the rudder 23 toward the bow 11 direction in the captain direction X. It is provided in the range of 5.0 Dp or less. Preferably, the bilge fins 24 and 25 are provided in the range A1 of 2.0 Dp or more and 5.0 Dp or less from the rotation center line RCL of the rudder 23 toward the bow 11 direction in the captain direction X. When the bilge fins 24 and 25 are provided in this range A1, the bilge fins 24 and 25 are set to the negative pressure surfaces 24a and 25a on the upper surface side in the ship height direction Z and the positive pressure surfaces 24b and 25b on the lower surface side in the ship height direction Z. To. The bilge fins 24 and 25 are set to have a length along the captain direction X, that is, a cord length C of 0.5% or more of the captain and 5.0% or less of the captain.

Here, the shapes of the bilge fins 24 and 25 will be described in detail, but since the bilge fins 24 and 25 have almost the same shape, only the bilge fin 25 will be described.

FIG. 4 is a perspective view of the bilge fin 25 seen from the rear of the hull 10. The bilge fin 25 is a negative pressure surface 25a having a curved shape along the captain direction X on the upper surface side and a positive pressure surface 25b having a substantially linear shape on the lower surface side along the captain direction X. In the bilge fin 25, the mounting surface 25c of the root portion 31 is fixed to the starboard bilge 15a in the hull 10. In this case, the mounting angle of the base portion 31 of the bilge fin 25 with respect to the outer surface of the hull 10 is preferably set to 90 degrees. Here, the mounting angle of the root portion 31 is the angle between the negative pressure surface 25a and the positive pressure surface 25b with respect to the outer surface of the hull 10. However, the manufacturing error of the hull 10 and the bilge fin 25 and the mounting error of the bilge fin 25 with respect to the hull 10 are included. In the bilge fin 25, the end surface 25d of the tip portion 32 has a planar shape, but the intersection of the end surface 25d and the negative pressure surface 25a and the intersection of the end surface 25d and the positive pressure surface 25b have a curved shape instead of an acute angle shape, or the end surface 25d. The whole may have a curved shape instead of a planar shape.

The bilge fin 25 is fixed to the curved starboard bilge 15a of the hull 10, and FIG. 5 is a schematic view of the bilge fin 25 viewed from the starboard 15 side when the starboard bilge 15a is a plane. The bilge fins 25 are arranged so as to be inclined with respect to the horizontal plane H so that the rear end portion 34 is located on the upper side in the ship height direction Z with respect to the front end portion 33. The root portion 31 is tilted with respect to the horizontal plane H at a first angle θ1, and the tip portion 32 is tilted with respect to the horizontal plane H at a second angle θ2 larger than the first angle θ1.

In FIG. 6, the solid line represents the cross-sectional shape of the front end portion 33 obtained by cutting the front end portion 33 of the bilge fin 25 along the plane along the beam direction Y and the ship height direction Z, and the two-point chain line represents the rear end portion of the bilge fin 25. It represents the cross-sectional shape of the rear end portion 34 obtained by cutting 34 in a plane along the ship width direction Y and the ship height direction Z. In the bilge fin 25, the front end portion 33 in the captain direction X has a linear shape from the root portion 31 toward the tip portion 32, and the rear end portion 34 in the captain direction X moves upward from the root portion 31 toward the tip portion 32. It has a curved shape (or bent shape). Therefore, the bilge fin 25 has a twisted shape such that the rear end portion 34 of the tip portion 32 extends upward in the ship height direction Z with respect to the rear end portion 34 of the root portion 31. In this case, the bilge fin 25 preferably has a curved shape (or bent shape) in which the negative pressure surface 25a and the positive pressure surface 25b are smoothly continuous.

Here, the first angle θ1 with respect to the horizontal plane H of the root portion 31 and the second angle θ2 with respect to the horizontal plane H of the tip portion 32 are different, but the first angle θ1 and the second angle θ2 are different in the range of 3 deg to 100 deg. It is preferable to do so.

FIG. 7 is a graph showing the optimum flow direction angle of the bilge fin 25 at a predetermined position from the rotation center line RCL of the rudder 23 to the bow 11 direction in the captain direction X obtained by thermo-fluid analysis (CFD). In this graph, the horizontal axis is the ratio (%) of the distance from the hull 10 to the diameter of the propeller 22, and the vertical axis is the flow direction angle (deg) of the bilge fin 25. Here, 0 deg is a horizontal position, “+” is an inclination such that the rear end portion of the bilge fin 25 is located upward, and “−” is an inclination such that the rear end portion of the bilge fin 25 is located downward. The α1 represented by the alternate long and short dash line is the flow direction angle of the bilge fin 25 at a position 2.5% of the captain from the rotation center line RCL of the rudder 23 toward the bow 11 direction in the captain direction X. Α2 represented by a solid line is the flow direction angle of the bilge fin 25 at a position of 5% of the captain from the rotation center line RCL of the rudder 23 toward the bow 11 direction in the captain direction X. Α3 represented by a dotted line is the flow direction angle of the bilge fin 25 at a position of 10% of the captain from the rotation center line RCL of the rudder 23 toward the bow 11 direction in the captain direction X. Α4 represented by the alternate long and short dash line is the flow direction angle of the bilge fin 25 at a position of 15% of the captain from the rotation center line RCL of the rudder 23 toward the bow 11 direction in the captain direction X.

As can be seen from the graph of FIG. 7, the flow direction angle α1 of the bilge fin 25 at the position of 2.5% of the captain is 75 deg at 0%, decreases from this, and becomes -25 deg at 30%, so the deviation. Is 100 deg. The flow direction angle α2 of the bilge fin 25 at the position of 5% of the captain is 30 deg at 0%, decreases from this, becomes -15 deg at 12%, and is almost constant up to 30%, so the deviation is 45 deg. .. The flow direction angle α3 of the bilge fin 25 at the position of 10% of the captain is -20 deg at 0%, and slightly increases from this to -10 deg at 30%, so that the deviation is 10 deg. The flow direction angle α4 of the bilge fin 25 at the position of 15% of the captain is -18 deg at 0%, and slightly increases from this to -15 deg at 5%, so that the deviation is 3 deg.

As a result, the deviation of the rudder 23 from the rotation center line RCL at the position of 15% of the master is 3 deg, and the deviation of the rudder 23 from the rotation center line RCL of 2.5% of the captain is 100 deg. Therefore, the difference between the first angle θ1 and the second angle θ2 is preferably in the range of 3 deg to 100 deg.

Further, as shown in FIG. 3, the center line of rotation of the propeller 22 is PCL, the width of the ship is W, the radius of rotation of the propeller 22 is R (= Dp / 2), and the center line of the hull 10 in the width direction Y is CL. The connecting line connecting the rotation center line PCL and the position P1 on the baseline B of the ship bottom 13 separated from the center line CL by W / 4 in the beam width direction Y is L1, and the ship height direction Z from the rotation center line PCL. L2 is a connecting line connecting the position P2 above 1.1R and the position P3 on the baseline B of the bottom 13 separated from the center line CL by W / 2 in the width direction Y. The bilge fin 25 is provided in the region between the connecting line L1 and the connecting line L2.

The length of the bilge fin 25 in the direction away from the hull 10 is set in the range of 1% or more and 15% or less of the rotation diameter Dp of the propeller 22. As shown in FIG. 7, the flow direction angle α2 of the bilge fin 25 at a position of 5% of the master from the rotation center line RCL of the rudder 23 is set to a range of 15% or less because it is a constant angle at 12%. Is preferable.

As described above, in the bilge fins of the first embodiment, in the bilge fins 24 and 25 provided on the bilge 14a and 15a of the hull 10, the first angle θ1 with respect to the horizontal plane H of the root portion 31 attached to the hull 10 and the hull 10 The second angle θ2 with respect to the horizontal plane H of the tip portion 32 separated from the above is different.

Therefore, since the first angle θ1 of the root portion 31 attached to the hull 10 and the second angle θ2 of the tip portion 32 are different, the water flow flowing backward along the port 14 and the starboard 15 and the rear along the bottom 13 The bilge vortex generated by the intersection of the flowing water flows is properly guided to the rotating surface of the propeller 22 by the bilge fins 24 and 25 having different angles at the root portion 31 and the tip portion 32, and the propulsion efficiency of the propeller 22 is improved. In addition to being able to improve, it is possible to suppress the increase in size of the bilge fins 24 and 25 and suppress the increase in propulsion resistance.

In the bilge fin of the first embodiment, the second angle θ2 is set larger than the first angle θ1. Therefore, the water flow away from the hull 10 can be effectively guided to the rotating surface of the propeller 22.

In the bilge fin of the first embodiment, the front end portion 33 in the captain direction X has a linear shape from the root portion 31 to the tip portion 32, and the rear end portion 34 in the captain direction X has a linear shape from the root portion 31 to the tip portion 32. It has a curved or bent shape. Therefore, the bilge vortex can be effectively guided to the rotating surface of the propeller 22.

In the bilge fin of the first embodiment, the first angle θ1 and the second angle θ2 are different in the range of 3 deg to 100 deg. Therefore, the bilge vortex can be effectively guided to the rotating surface of the propeller 22.

Further, in the ship of the first embodiment, the hull 10 and the propeller 22 arranged at the stern 12 of the hull 10, the rudder 23 arranged behind the propeller 22 at the stern 12 of the hull 10, and the bilge fins 24 and 25. It is equipped with.

Therefore, since the first angle θ1 of the root portion 31 of the bilge fins 24 and 25 provided on the bilge 14a and 15a of the hull 10 and the second angle θ2 of the tip portion 32 are different, the rearward along the port 14 and the starboard 15. The bilge vortex generated by the intersection of the flowing water flow and the water flow flowing backward along the bottom 13 is properly guided to the rotating surface of the propeller 22 by the bilge fins 24 and 25 having different angles at the root portion 31 and the tip portion 32. Therefore, the propulsion efficiency of the propeller 22 can be improved, and the increase in size of the bilge fins 24 and 25 can be suppressed to suppress the increase in propulsion resistance.

In the ship of the first embodiment, assuming that the rotation diameter of the propeller 22 is Dp, the bilge fins 24 and 25 are in the range of 0.5 Dp or more and 5.0 Dp or less from the rotation center line RCL of the rudder 23 toward the bow 11 direction. It is provided in. Therefore, since the bilge fins 24 and 25 are attached at appropriate positions in the captain's direction X, the bilge vortex can be appropriately guided to the rotating surface of the propeller 22 and the propulsion efficiency of the propeller 22 can be improved.

In the ship of the first embodiment, when the bilge fins 24 and 25 are provided in the range of 2.0 Dp or more and 5.0 Dp or less from the rotation center line RCL of the rudder 23 toward the bow 11 direction, the bilge fins 24 and 25 are provided. The upper surface side is set to the negative pressure surfaces 24a and 25a, and the lower surface side is set to the positive pressure surfaces 24b and 25b. Therefore, the bilge vortex can be appropriately guided to the rotating surface of the propeller 22.

In the ship of the first embodiment, assuming that the rotation center line of the propeller 22 is PCL, the ship width W, the rotation radius of the propeller 22 is R, and the center line CL in the ship width direction Y, the bilge fins 24 and 25 are the rotation center lines PCL. And the connecting line L1 connecting the center line CL and the position P1 on the baseline B of the ship bottom 13 separated by W / 4 in the width direction Y from the center line CL, and 1.1R upward from the rotation center line PCL in the ship height direction Z. It is provided in the area between the position P2 of the ship and the connecting line L2 connecting the position P3 on the baseline B of the bottom 13 separated from the center line CL by W / 2 in the width direction Y. Therefore, since the bilge fins 24 and 25 are attached at appropriate positions in the ship width direction Y, the bilge vortex can be appropriately guided to the rotating surface of the propeller 22 and the propulsion efficiency of the propeller 22 can be improved.

In the ship of the first embodiment, the mounting angle of the root portion 31 with respect to the hull 10 is set to 90 degrees. Therefore, it is possible to suppress a decrease in the support rigidity of the bilge fins 24 and 25.

In the ship of the first embodiment, the length of the bilge fins 24 and 25 in the direction away from the hull 10 is set in the range of 1% or more and 15% or less of the rotation diameter Dp of the propeller 22. Therefore, since the length of the bilge fins 24 and 25 is set to an appropriate length, the bilge fins 24 and 25 can be miniaturized, while the bilge vortex can be appropriately guided to the rotating surface of the propeller 22. ..

[Second Embodiment]
FIG. 8 is a schematic side view of the ship of the second embodiment, and FIG. 9 is a perspective view showing the stern fin of the second embodiment. The members having the same functions as those of the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the second embodiment, as shown in FIG. 8, the hull 10 is provided with bilge fins (stern fins) 41 and 42 on the port bilge 14a and the starboard bilge 15a, respectively. The bilge fins 41 and 42 have a symmetrical shape with respect to the center line CL. The bilge fin 42 has a first fin main body 43 and a second fin main body 44. The bilge fin 41 also has a similar configuration, although not shown.

As shown in FIGS. 8 and 9, in the bilge fin 42, the first fin body 43 constitutes a root portion attached to the hull 10, and the second fin body 44 constitutes a tip portion separated from the hull 10. .. The first angle of the first fin body 43 constituting the root portion attached to the hull 10 with respect to the horizontal plane is different from the second angle of the second fin body 44 constituting the tip portion separated from the hull 10 with respect to the horizontal plane. ing. In this case, the second angle of the second fin main body 44 is set larger than the first angle of the first fin main body 43.

The bilge fin 42 has a wing shape along the captain direction X, and the first fin body 43 is set to the negative pressure surface 43a on the upper surface side in the ship height direction Z and the positive pressure surface 43b on the lower surface side in the ship height direction Z. .. Similarly, in the second fin main body 44, the upper surface side in the ship height direction Z is set to the negative pressure surface 44a, and the lower surface side in the ship height direction Z is set to the positive pressure surface 44b. Then, in the bilge fin 42, the front end portion of the first fin main body 43 attached to the hull 10 and the front end portion of the second fin main body 44 separated from the hull 10 are located at the same position in the ship height direction Z, and the first fin main body 43 The rear end portion of the second fin body 44 with respect to the rear end portion is located on the upper side in the ship height direction Z.

As described above, the bilge fin and the ship of the second embodiment have the first fin main body 43 constituting the root portion and the second fin main body 44 constituting the tip portion.

Therefore, since the first fin main body 43 constituting the root portion and the second fin main body 44 constituting the tip portion are separately configured, it is not necessary to process the complicated surface shape of the bilge fin 42 (41), and the bilge fin is not required. 42 (41) can be easily manufactured, and the manufacturing cost can be reduced.

[Third Embodiment]
10 is a schematic side view of the ship of the third embodiment, and FIG. 11 is a perspective view showing the stern fin of the third embodiment. The members having the same functions as those of the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the third embodiment, as shown in FIG. 10, the hull 10 is provided with bilge fins (stern fins) 51 and 52 on the port bilge 14a and the starboard bilge 15a, respectively. The bilge fins 51 and 52 have a symmetrical shape with respect to the center line CL. Assuming that the rotation diameter of the propeller 22 is Dp (see FIG. 3), the bilge fins 51 and 52 are 0.5 Dp or more and 5.0 Dp or less from the rotation center line RCL of the rudder 23 toward the bow 11 direction in the captain direction X. Provided in the range. Preferably, the bilge fins 51 and 52 are provided in the range A2 of 0.5 Dp or more and less than 2.0 Dp from the rotation center line RCL of the rudder 23 toward the bow 11 direction in the captain direction X. The bilge fin 52 has a first fin main body 53 and a second fin main body 54. The bilge fin 51 also has a similar configuration, although not shown.

As shown in FIGS. 10 and 11, in the bilge fin 52, the first fin main body 53 constitutes a root portion attached to the hull 10, and the second fin main body 54 constitutes a tip portion separated from the hull 10. .. The first angle of the first fin body 53 constituting the root portion attached to the hull 10 with respect to the horizontal plane is different from the second angle of the second fin body 54 constituting the tip portion separated from the hull 10 with respect to the horizontal plane. ing. In this case, the second angle of the second fin main body 54 is set larger than the first angle of the first fin main body 53.

The bilge fin 52 has a wing shape along the captain direction X, and the first fin main body 53 is set to the positive pressure surface 53a on the upper surface side in the ship height direction Z and the negative pressure surface 53b on the lower surface side in the ship height direction Z. .. On the other hand, in the second fin main body 54, the upper surface side in the ship height direction Z is set to the negative pressure surface 54a, and the lower surface side in the ship height direction Z is set to the positive pressure surface 54b. Then, in the bilge fin 52, the front end portion of the first fin main body 53 attached to the hull 10 and the front end portion of the second fin main body 54 separated from the hull 10 are located at the same position in the ship height direction Z, and the first fin main body 53 The rear end portion of the second fin body 45 with respect to the rear end portion is located on the upper side in the ship height direction Z.

As described above, the bilge fin of the third embodiment has a first fin main body 53 constituting the root portion and a second fin main body 54 constituting the tip portion. Therefore, it is not necessary to process the complicated surface shape of the bilge fin 52 (51), the bilge fin 52 (51) can be easily manufactured, and the manufacturing cost can be reduced.

In the ship of the third embodiment, when the bilge fin 52 (51) is provided in the range of 0.5 Dp or more and less than 2.0 Dp from the rotation center line RCL of the rudder 23 toward the bow 11 direction, the bilge fin 52 (51) The upper surface side of the first fin body 53 in the ship height direction is set to the positive pressure surface 53a, the lower surface side in the ship height direction is set to the negative pressure surface 53b, and the upper surface side of the second fin body 54 in the ship height direction is the negative pressure surface. It is set to 54a, and the lower surface side in the ship height direction is set to the positive pressure surface 54b. Therefore, when the bilge fin 52 (51) is provided close to the rudder 23, the positive pressure surface 53a and the negative pressure surface 53b of the first fin main body 53 are set in reverse so that the bilge fin 52 (51) is sufficiently developed in the vicinity of the propeller 22. The vortex can be properly guided to the rotating surface of the propeller 22.

In the second and third embodiments described above, the bilge fin is composed of two first fin main bodies and a second fin main body, but it may be composed of three or more bilge fin main bodies. Further, in the third embodiment, the bilge fin is composed of two first fin main bodies and a second fin main body, but as in the first embodiment, the two first fin main bodies and the second fin main body are integrated. It may be composed of one bilge fin.

10 Hull 11 Hull 12 Stern 13 Stern bottom 14 Port 14a Port Bilge 15 Starboard 15a Starboard Bilge 22 Propeller 23 Steering 24, 25, 41, 42, 51, 52 Bilge Fins (Stern Fins)
24a, 25a, 43a, 44a, 53b, 54a Negative pressure surface 24b, 25b, 43b, 44b, 53a, 54b Positive pressure surface 31 Root 32 Tip 33 Front end 34 Rear end α1, α2, α3, α4 Flow angle θ1 1 angle θ2 2nd angle A1, A2 range C cord length CL center line Dp rotation diameter L1, L2 connecting line P1, P2, P3 position PCL propeller rotation center line (rotation center)
R radius of rotation RCL Rudder center of rotation (center of rotation)
W Ship width WL Full load draft line X Captain direction Y Ship width direction Z Ship height direction

Claims (12)

At the stern fins on the hull bilge
The first angle of the root portion attached to the hull with respect to the horizontal plane and the second angle of the tip portion separated from the hull with respect to the horizontal plane are different.
The front end in the captain direction has a linear shape from the root to the tip, and the rear end in the captain direction has a curved or bent shape in which the rear end moves upward from the root to the tip.
The thickness decreases from the front end to the rear end.
It has a twisted shape such that the rear end portion of the tip portion extends upward in the ship height direction with respect to the front end portion of the tip portion.
A stern fin characterized by that. The stern fin according to claim 1, wherein the second angle is set larger than the first angle. The stern fin according to claim 1 or 2, wherein the first fin main body constituting the root portion and the second fin main body constituting the tip portion are included. The stern fin according to any one of claims 1 to 3, wherein the first angle and the second angle differ in the range of 3 deg to 100 deg. With the hull,
The propeller placed at the stern of the hull and
A rudder located behind the propeller at the stern of the hull,
The stern fin according to any one of claims 1 to 4, and the stern fin.
A vessel characterized by being equipped with. The fifth aspect of claim 5, wherein the stern fin is provided in a range of 0.5 Dp or more and 5.0 Dp or less from the center of rotation of the rudder toward the bow, where the rotation diameter of the propeller is Dp. Ships. When the stern fin is provided in a range of 2.0 Dp or more and 5.0 Dp or less from the center of rotation of the rudder toward the bow, the stern fin is set to a negative pressure surface on the upper surface side in the ship height direction and the ship height. The ship according to claim 5 or 6, wherein the lower surface side in the direction is set to a positive pressure surface. When the stern fin is provided in a range of 0.5 Dp or more and less than 2.0 Dp from the center of rotation of the rudder toward the bow, the stern fin is set so that the upper surface side of the root portion in the ship height direction is a positive pressure surface. The lower surface side in the ship height direction is set as the negative pressure surface, the upper surface side in the ship height direction of the tip portion is set as the negative pressure surface, and the lower surface side in the ship height direction is set as the positive pressure surface. The ship according to item 5 or claim 6. Assuming that the center of rotation of the propeller is PCL, the width of the ship is W, the radius of rotation of the propeller is R, and the center line in the width direction is CL, the stern fin is in the width direction from the center of rotation PCL and the center line CL. The connecting line L1 connecting the position on the baseline of the bottom of the ship separated by W / 4 and the position 1.1R above the center of rotation PCL in the height direction and W in the width direction from the center line CL. The ship according to any one of claims 5 to 8, wherein the ship is provided in a region between the connecting line L2 and the position of the bottom of the ship separated by / 2 on the baseline. The ship according to any one of claims 5 to 9, wherein the attachment angle of the root portion to the hull is set to 90 degrees. Any of claims 5 to 10, wherein the length of the stern fin in the direction away from the hull is set in a range of 1% or more and 15% or less of the rotation diameter Dp of the propeller. The ship described in paragraph 1. The ship according to any one of claims 5 to 11, wherein the hull has a square coefficient set to be larger than 0.75.

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