KR20180114084A - Ship - Google Patents

Abstract

The present invention provides a ship capable of suppressing a ripple phenomenon derived from a stern end and a frictional resistance caused by a single piece and suppressing a ripple phenomenon on a stern side.
The ship 1 according to the present invention has a first projecting frame portion 21 formed at both side positions of the ship bottom 10b of the stern side 10a with the ship center line CL therebetween and having a predetermined length and a first projecting frame portion 21 A first protruding rim portion 22 formed at an outer side position and having a predetermined length and a first flow path 31 formed between the first protruding rim portion 21 and having a concave shape and a first protruding rim portion 21 and a second protruding rim A first rear end protruding portion 41 formed between the second protruding end portion 21 and the second protruding end portion 10a of the second flow path 32 and the stern end 10a of the first flow path 31, And a second rear end protruding portion 42 formed to connect the first protruding rim portion 21 and the second protruding rim portion 22 to the stern end 10a.

Description

Ship

The present invention relates to a ship, in particular, a ship which sails with a furd number of about 0.2 to 0.4.

A ship, such as a ferry or car carrier that sails at a fur number of Fn (Fn = BW / (interline length x gravity acceleration) ^1/2 ) of 0.2 to 0.4, sails by the propulsive force generated by the propeller. Such a ship is said to be a ship having a small hull resistance at the time of navigation, which is connected with an improvement in the speed of the ship and has a good operational performance. Therefore, in the design of the ship, the present inventors completed the present invention by finding out a shape in which the hull resistance is reduced by experiment or experience while satisfying the design conditions such as the operational state and the displacement amount. Hull resistance usually increases due to the ripple phenomenon of the bow (bow), the ripple phenomenon accompanied by undulations of the side waves running along the side, and the rising phenomenon of the stern wave derived from the stern end. Therefore, in order to reduce the hull resistance, it is desired to improve the ripple phenomenon of the bow, the ripple phenomenon caused by the side wave, and the rising phenomenon of the sidelobe.

Generally, in a ship, a water flow flowing along a line bottom (a ship bottom surface) and a side line from an athlete abruptly abruptly becomes a stern end, and a water flow rises near a center of aft end near a water surface, In the vicinity of the ship side, the ship side flows. In addition, when the ship is navigating, a phenomenon called sinkage occurs in which the hull sinks below the water surface. Frictional resistance is generated between the surface of the hull under the water and viscous seawater, but the frictional resistance increases as the flood area increases, and this frictional resistance becomes the hull resistance. Particularly, the vessels of Patent Documents 1 to 3 are known as a ship in which the resistance of the hull is reduced by paying attention to the frictional resistance caused by the swing of the water flow of the aft end and the sway wave.

Japanese Laid-Open Patent Publication No. 2001-219892 Japanese Patent Publication No. 3490392 Japanese Patent Publication No. 5634567

However, in such a ship, all of the ships are provided with a rear end protruding portion called a trim tab or wedge at the stern end, thereby suppressing the rising phenomenon of the stern wave derived from the stern end, and at the same time, However, it is difficult to suppress the ripple phenomenon on the stern side portion, and a problem that sufficient reduction in hull resistance can not be obtained has arisen.

In order to solve the above problems, the present invention provides a ship capable of reducing the frictional resistance caused by the ripple phenomenon and sunk wave derived from the stern end and suppressing the ripple phenomenon on the stern side.

A ship according to the present invention comprises a first projecting frame portion formed at both side positions of a stern side ship bottom centerline and having a predetermined length and a second projecting frame portion formed at an outer position of the first projecting frame portion, A first protrusion rim portion formed between the first protruding rim portion and the first protruding rim portion and having a concave shape and a second protruding rim portion formed between the first protruding rim portion and the second protruding rim portion, A first rear end protruding portion formed so as to connect the first protruding rim portion to the stern end of the first flow path and a second rear end protruding portion formed to connect the first protruding rim portion and the second protruding rim portion to the stern end of the second flow path, And a second rear end protruding portion.

The ship of the present invention has a first projecting rim and a second projecting rim at the bottom of the stern side and is characterized in that the water flow along the bottom surface near the center line of the ship near the planned waterline of the stern, It is possible to draw a flow of water flowing along the side of the stern, to rectify the disturbed flow such as the peeling phenomenon, and to guide it toward the stern end. At this time, since the first flow path is formed between the first projecting rim portions, the water flow is accelerated in the axial direction in the first flow path. And, since the water flow accelerated by the axial flow corresponds to the first rear end protrusion formed at the stern end of the first flow path, the rising of the water flow derived from the stern end is suppressed. Moreover, since the second flow path is formed between the first projecting rim and the second projecting rim, it is possible to suppress the ripple phenomenon of the stern side wave. In addition, since the first rear end protruding portion and the second rear end protruding portion are formed at the aft end, an attack angle can be given to the water flow accelerated to the aft end. As a result, the water flow is decelerated and deflected downward to the rear, resulting in the wing theory effect of increasing the pressure at the bottom of the stern line, so that the stern portion of the ship can be lifted. When the ship is navigating, the entire hull referred to as a singei keeper sinks, but the posture at the time of navigation is changed by the lifting effect of the stern end by the first rear end protruding portion and the second rear end protruding portion, Can be lifted. This reduces the flooding area of the hull, thereby reducing the frictional resistance of the surface of the hull.

In a preferred embodiment of the present invention, the first flow path is curved in a concave shape upward with respect to a straight line connecting the first projecting rim and the ship's center line, and the first flow path is curved in the shape of a center line between the first projecting rim and the ship center line And the second flow path is curved upward in a concave shape with respect to a straight line connecting the first projecting rim and the second projecting rim, and at the same time, the first projecting rim and the second projecting rim are curved in a concave shape with respect to a straight line connecting the front end and the rear end, And curves upward in a concave shape with respect to a straight line connecting the front end and the rear end of the center line between the rim portion and the second projecting rim portion.

In a preferred embodiment of the present invention, the first flow path is formed by a straight line connecting between the first projecting edge portions and a straight line connecting the front end and the rear end of the center line between the first projecting edge portions And the second flow path is curved upward in a concave shape with respect to a straight line connecting the first projecting rim and the second projecting rim, and at the same time, the first projecting rim and the second projecting rim And curves upward in a concave shape with respect to a straight line connecting the front end and the rear end of the center line between the frame portion and the frame portion.

In this way, by making the first flow path and the second flow path smooth and curving in a concave shape, the flow of water passing through the first flow path and the second flow path is suppressed from peeling or waving at the corners of the flow path It is possible to suppress the rising of the water flow derived from the aft end or the ripple phenomenon of the aft side side wave.

In the preferred embodiment, the first flow path is formed upward from a position 0.3 times lower than the planned draft from the planned waterline, and the second flow path extends from a position 0.1 times lower than the planned draft to the upper side Respectively.

In the preferred embodiment, the first flow path and the second flow path are formed rearward at a position 0.2 times ahead of the waterline from the aft waterline.

In the preferred embodiment, the lower end of the first rear end protruding portion is located within a range from the planned waterline at a position 0.2 times higher than the planned draft to the planned waterline, and the lower end of the second rear end protruding portion is located at a distance from the planned waterline Is located within a range from the position 0.3 times above the planned draft to the planned waterline.

In a preferred embodiment, the number of furudes is 0.2 to 0.4.

According to the ship of the present invention, it is possible to reduce the frictional resistance due to the ripple phenomenon and the sinkage derived from the stern end, and to suppress the ripple phenomenon on the stern side.

1 is a perspective view showing an embodiment of a stern part of a ship according to the present invention.
2 is a side view of the ship of Fig.
3 is a bottom view of the ship of Fig.
4 is a cross-sectional view taken along the line A-A of the ship of Fig.
5 is a cross-sectional view taken along the line B-B of the ship of Fig. 2;
Fig. 6 is a comparative diagram of the aft-side side waveform.
7 is a comparative view of the hull resistance curve.
Fig. 8 is a cross-sectional view taken along line A-A of Fig. 2, showing another embodiment of a stern portion of a ship according to the present invention. Fig.
Fig. 9 is a cross-sectional view taken along line A-A in Fig. 2, showing another embodiment of a stern portion of a ship according to the present invention. Fig.
10 is a cross-sectional view taken along line A-A of Fig. 2, showing another embodiment of a stern portion of a ship according to the present invention.
Fig. 11 is a cross-sectional view taken along line A-A in Fig. 2, showing another embodiment of a stern portion of a ship according to the present invention. Fig.
Fig. 12 is a cross-sectional view taken along line A-A in Fig. 2, showing another embodiment of a stern portion of a ship according to the present invention. Fig.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a ship according to the present invention will be described with reference to Figs. 1 to 5. Fig. The ship 1 of the present invention is a general merchant ship of a displacement type such as a ferry and a car carrier for which the number of furudes is about 0.2 to 0.4 and is a ship 3 and a propeller 2 for generating propulsion at the stern and a key 3 for ship navigation (See FIG. 2). 1 and 3, the propeller 2 and the key 3 are omitted for easy understanding of the drawings. In the following description, the forward side and the aft side are defined as the front side and the rear side, respectively. In the horizontal plane, the direction orthogonal to the front-rear direction is the left-right direction, and the direction orthogonal to the front-rear direction and the right- Further, the fore-and-aft direction, that is, the direction of the ship ?, is set to the X direction, the lateral width direction, in other words, the Y direction, and the up and down direction is set to the Z direction.

A first projecting rim 21 formed at both side positions of the ship body centerline CL between the bottom 10b of the stern 10a of the hull 10 and a second projecting rim 22 formed at an outer position of the first projecting rim 21 Respectively. Here, the ship center line CL is a line passing through the center of the ship 10 in the line width direction. In the present embodiment, protrusions 23 are formed along the ship center line CL at the bottom 10b on the stern 10a side (see Fig. 4). A first flow path 31 is formed at a bottom 10b portion between the first projecting rim 21 and the ship center line CL and at a bottom 10b portion between the first projecting rim 21 and the second projecting rim 22, Two flow paths 32 are formed. The stern end 10a of the first flow path 31 is provided with a first rear end protruding portion 41 so as to extend between the first projecting rims 21 and a stern end 10a of the second flow path 32 is provided with a first projecting rim 21 A second rear end protruding portion 42 is formed so as to connect with the second protruding edge portion 22. [

As shown in Figs. 4 and 5, the first projecting rim 21 and the second projecting rim 22 have a cross-sectional shape whose tip is sharpened, and have a predetermined length in the skeleton direction (X direction in Figs. 1 to 3) It is extended. Specifically, the first projecting rim 21 and the second projecting rim 22 extend toward the stern end 10a from a position that is a predetermined distance L from the aft waterfront line AP. The predetermined distance L is preferably short in order to avoid an increase in hull resistance, and is generally shorter than 0.2 times the inter-waterline length Lpp.

The front end P21F and the rear end P21A of the first projecting rim 21 are formed such that the distances B21F and B21A from the ship body center line CL are respectively 0.6 times or less of the maximum half width (the maximum half length) BH of the hull 10 have. The front end P22F and the rear end P22A of the second projecting rim 22 are arranged such that the distances B22F and B22A from the ship body center line CL are larger than the distances B21F and B21A and 0.4 times or more the maximum half- As shown in Fig.

The front end P21F of the first projecting rim 21 and the front end P22F of the second projecting rim 22 are substantially flush with the line bottom 10b so as to prevent hull resistance. The rear end P21A of the first projecting rim 21 and the rear end P22A of the second projecting rim 22 are also positioned at substantially the same position as the lower end of the first rear end projecting portion 41 and the lower end of the second rear end projecting portion 42 .

The first flow path 31 is formed between the first projecting rim portions 21. In the present embodiment, the first flow path 31 is divided into right and left by the projecting portions 23 along the ship center line CL. The first flow path 31 has a center line T1 between the first projecting rim portion 21 and the ship body center line CL, and is disposed near the ship body centerline CL. The bottom surface of the first flow path 31 is curved upward in a concave shape with respect to a straight line L1 connecting the ship's center line CL with the first projecting rim 21 and is curved upward toward a straight line L3 connecting the front end PT1F and the rear end PT1A of the center line T1 And curved in a concave shape. The first flow path 31 is disposed above the planned waterline DL from a shallow water surface area below the planned waterline DL. More specifically, the front end PT1F of the center line T1 of the first flow path 31 is set such that the distance Z4 from the planned waterline DL to the downward direction is within 0.3 times the planned draft d, Is set to be within 0.2 times the length Lpp.

The second flow path 32 is formed by the first projecting rim 21 and the second projecting rim 22 and has a center line T2 between the first projecting rim 21 and the second projecting rim 22, have. The bottom surface of the second flow path 32 is bent concavely upwardly with respect to a straight line L2 connecting the first projecting rim 21 and the second projecting rim 22 and at the same time a straight line L4 connecting the front end PT2F and the rear end PT2A of the center line T2 And curved upward in a concave shape. The second flow path 32 is disposed above the planned waterline DL from the shallow water surface area below the planned waterline DL or near the planned waterline DL. More specifically, the front end PT2F of the center line T2 of the second flow path 32 is set such that the distance Z3 from the planned waterline DL to the upper or lower side is within 0.1 times the planned draft d and the distance L from the aft waterline AP to the front , And the distance between the waterlines is less than 0.2 times the length Lpp.

It is preferable that the first flow path 31 and the second flow path 32 are formed so as to extend to the upper side of the propeller 2 and the key 3. [ With this configuration, the water flow on the surface of the hull 10 in the vicinity of the ship center line CL is rectified and guided toward the key 3. As a result, the increase of the resistance by the key 3 is reduced, the effect of the key 3 at the time of steering is improved, and it is possible to contribute to the improvement of the ship building performance and the safety.

The first rear end projecting portion 41 and the second rear end projecting portion 42 extend vertically from the side of the stern end 10a when viewed from the side and extend forward at a predetermined angle to form a substantially triangular shape. The inclination of the front side can be inclined at an arbitrary angle if the inclination is such that an attack angle is given to the water flow flowing toward the aft end 10a. The rear end PT1A at the center line T1 of the first rear end projecting portion 41 is disposed at a position of distance Z11 from the planned waterline DL upwards and the distance Z11 is within 0.2 times the planned draft d. Likewise, the rear end PT2A at the center line T2 of the second rear end protruding portion 42 is also disposed at a position at a distance Z12 upward from the planned waterline DL, and the distance Z12 is within 0.3 times the planned draft d.

The position of the center line T1 of the first flow path 31 in the skeleton direction is located at a distance Z21 from the rear end PT1A at the center line T1 of the first rear end projecting portion 41 and the distance Z21 is the planned draft d Which is 0.2 times smaller than that of the conventional art. Likewise, the position of the center line T2 of the second flow path 32 in the skeleton direction is the position above the rear end PT2A at the center line T2 of the second rear end protruding portion 42 at a distance Z22, and the distance Z22 corresponds to the planned draft d < / RTI >

Next, how the ship 1 of the present invention can suppress the side wave to some extent and reduce the hull resistance to some extent will be described in comparison with the comparative example. Comparative Example 1 is a conventional general ship, which is a type of ship which does not have a first flow path, a second flow path, a first rear end projection and a second rear end projection on the bottom. Comparative Example 2 is a type of ship in which a first rear end protruding portion 41 is formed on the bottom of the first flow path 31.

Fig. 6 shows the side waveforms of the present invention, Comparative Example 1 and Comparative Example 2. The side waveform represents the position from the center of the ship in the skipper direction and the position of the center of the hull, where 0.0 represents the position of the ship's center, and 0.5 represents the position of the aft waterline AP in X / Lpp (inter-track length) on the horizontal axis. The position of the horizontal axis 0.52 represents the stern end 10a. Z / Lpp of the vertical axis is a value obtained by dividing the height Z of the waveform by the inter-line length Lpp and making it non-dimensional. As shown in Fig. 6, in the present invention, the height of the waveform is lower than that of Comparative Example 1 at the aft end 10a. In addition, the waveform of the stern end 10a is smaller than those of the comparative examples 1 and 2, and the ridge of the stern flow (the waveform behind the stern end) derived from the stern end 10a is also reduced. The fact that the height Z of the waveform is reduced in this way indicates that the ripple phenomenon of the stern 10a is being improved. From FIG. 6, it is demonstrated that the present invention can suppress the ripple phenomenon of the stern 10a.

Fig. 7 shows hull resistance of the present invention, Comparative Example 1 and Comparative Example 2. The horizontal axis Fn is the number of furudes during navigation, and the vertical axis rR is the hull resistance. As apparent from Fig. 7, in the frudes number near the sailing speed, in the present invention, the hull resistance is reduced for Comparative Examples 1 and 2, and it is demonstrated that the present invention can reduce hull resistance.

In the ship 1, the water flow flowing along the line bottom 10b or the side of the ship from the bow suddenly cuts off at the aft end 10a, so that the water flow rises near the center of the aft end 10a near the water surface, The side flow is diffused in the vicinity, and a stern wave called wave that is dragged occurs. When the ripple phenomenon at these stern ends 10a is increased, the resistance of the hull is increased.

However, in the present embodiment, the first projecting rim 21 is formed on the bottom 10b of the stern 10a so that the bottom 10b of the stern 10a near the planned waterline DL near the centerline CL of the ship, b, which is caused by the peeling phenomenon, can be induced and accelerated while being rectified. In addition, the second protruding rim portion 22 is formed on the bottom 10b of the stern 10a side, so that the water flow flowing along the side of the stern 10a can be attracted to accelerate while suppressing the diffusion phenomenon of the stern wave. At this time, since the first flow path 31 is formed between the first projecting rim portions 21, the water flow is accelerated in the axial direction in the first flow path 31. The water flow accelerated by the axial flow corresponds to the first rear end protruding portion 41 formed at the stern end 10a of the first flow path 31, so that the rising of the water flow derived from the stern end 10a is suppressed. Further, since the second flow path 32 is formed between the first projecting rim 21 and the second projecting rim 22, it is possible to suppress the ripening of the aft-side side wave.

In addition, since the stern end 10a is provided with the first rear end protruding portion 41 and the second rear end protruding portion 42, it is possible to reduce the attack angle with respect to the flow of water accelerated and accelerated toward the stern end 10a. Thereby, the water flow is decelerated and deflected downward to the rear, resulting in a wing theoretical effect of increasing the pressure of the line bottom surface 10b of the aft end 10a, so that the aft aft portion 10a can be lifted. When the ship 1 sails, the entire hull 10, which is called a sinkage, sinks. However, due to the lift effect of the stern end 10a by the first rear end protruding portion 41 and the second rear end protruding portion 42, The hull 10 can be lifted entirely by changing the attitude of the hour. This reduces the flood area of the hull 10, thereby reducing the frictional resistance on the surface of the hull 10 as well.

Further, in the present embodiment, the first flow path 31 and the second flow path 32 are smoothly curved in a concave shape, so that the flow of water passing through the first flow path 31 and the second flow path 32 corresponds to the corner portion of the flow path So that it is possible to suppress the rise of the water flow derived from the aft end 10a or the ripple phenomenon of the aft side side wave.

In the present embodiment, the first flow path 31 and the second flow path 32 are arranged above the planned waterline DL from the shallow water surface area below the planned waterline DL, and further from the aft waterline AP The distance L is set to be within 0.2 times of the inter-line length Lpp. By forming the first flow path 31 and the second flow path 32 in such a position, the first flow path 31 and the second flow path 32 do not affect the flow of the water flow along the bottom 10b ahead of the propeller 2, , The influence on the performance of the propeller 2 can be avoided as much as possible. When the first protruding rim 21 for forming the first flow path 31 is formed from a position substantially ahead of the apex water line AP and is formed up to a deep line bottom 10b below the planned waterline DL, The resistance of the first protruding rim portion 21 is increased and the water flow along the first rim portion 21 is adversely affected. However, the first flow path 31 is disposed above the planned waterline DL from the shallow water surface area below the planned waterline DL, and the distance L from the aft waterline AP to the forward direction is larger than the waterline length Lpp The adverse effect on the water flow along the line bottom 10b can be suppressed as much as possible and the increase in the hull resistance due to the adverse effect on the water flow near the bottom 10b can be avoided.

In addition, in the present embodiment, since the ship resistance is reduced, the fuel consumption consumed when the ship 1 is navigated is improved, and efficient ship navigation can be performed.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention.

For example, the distances L, B21F, B21A, B22F, B22A, Z11, Z12, Z21, Z22, Z3, and Z4 specified in the above embodiment are only for reference and can be appropriately changed depending on the shape of the vessel 1.

In the above embodiment, the first protruding rim 21 and the second rim 22 have a sharp cross-sectional shape. However, the cross-sectional shapes of the first protruding rim 21 and the second rim 22, The present invention is not limited to the above embodiment. For example, as shown in Fig. 8, the first projecting rim 21 and the second projecting rim 22 may have a cross-sectional shape in which the tip ends are curved in an arc shape. As shown in Fig. 9, the first projecting rim 21 may have a circular arc shape at its tip, and the second projecting rim 22 may have a sharp-tipped cross-sectional shape. The opposite is also possible.

In the above embodiment, the first flow path 31 is divided into right and left by the projecting portion 23 along the ship center line CL, but the first flow path 31 is not limited to the above embodiment. For example, as shown in Fig. 9, it can be formed by the first projecting rim 21 formed on both sides with the ship body center line CL therebetween. In this case, the bottom surface of the first flow path 31 is bent in a concave shape upward with respect to a straight line L5 connecting between the first projecting rim portions 21, and a straight line connecting the front end and the rear end of the center line between the first projecting rim portions 21 As shown in Fig.

In the above embodiment, the first flow path 31 and the second flow path 32 are formed to be curved concavely upward with respect to the straight line L1 and the straight line L2, but the present invention is not limited to this form. For example, as shown in Fig. 10 or 11, the first flow path 31 and the second flow path 32 may be formed so as to be upwardly trapezoidal or triangular in shape with respect to the straight line L1 and the straight line L2. The first flow path 31 and the second flow path 32 do not always need to have the same cross sectional shape. The first flow path 31 is recessed in a trapezoidal cross section in the direction of the straight line L1, And a triangular-shaped depression is formed in the upper side. In addition, any cross-sectional shape of the first flow path 31 and the second flow path 32 can be obtained if the cross-sectional shape of the first flow path 31 and the second flow path 32 is furthest upward. As shown in Fig. 12, the projections 24 having a substantially triangular cross section are mounted on the bottom 10b by welding or the like so that the first projecting rim 21, the second projecting rim 22, the first flow path 31, The flow path 32 may be formed. At this time, it is preferable that the first flow path 31 and the second flow path 32 are formed with the projections 24 so as to curve upward in a concave shape with respect to a straight line connecting the projections 24.

Although the stern end 10a side of the first rear end projecting portion 41 and the second rear end projecting portion 42 extends vertically in the above embodiment, the shape of the stern end 10a side of the first rear end projecting portion 41 and the second rear end projecting portion 42 Is not limited to this form. For example, when the stern end 10a of the hull 10 has a sloped surface such that the upper portion is located on the rear side from the vertical plane, the surface of the first stern end protruding portion 41 and the second stern end protruding portion 42 on the stern end 10a side, May be extended along the plane of the aft end 10a of the stator 10a. The surfaces of the first rear end projecting portion 41 and the second rear end projecting portion 42 on the stern end 10a side are not necessarily required to follow the surface of the stern end 10a of the hull 10 and may be extended with an arbitrary inclination relative to the vertical surface .

1 vessel
10 a stern
10 b bottom
21 First protruding rim
22 Second protruding rim
31 1st Euro
32 second euro
41 first rear end protrusion
42 second rear end protrusion
AP Aft Repair
CL center line
d Planned draft
DL Planned Waterline
Lpp Waterline length
The center line between the T1 first projecting rim and the ship center line
The center line between the T2 first projecting rim and the second projecting rim
X-master direction
Y line width direction

Claims (7)

A first projected rim portion formed at both side positions with a ship center line of the bottom of the stern side interposed therebetween and having a predetermined length,
A second protruding rim portion formed at an outer position of the first protruding rim portion and having a predetermined length,
A first flow path formed between the first projecting rim portions and having a concave shape,
A second flow path formed between the first projecting rim and the second projecting rim and having a concave shape;
A first rear end protruding portion formed at a stern end of the first flow path to connect between the first protruding rim portions,
And a second rear end protruding portion formed at a stern end of the second flow path so as to connect the first protruding rim portion and the second protruding rim portion.
The method according to claim 1,
Wherein the first flow path is curved upward in a concave shape with respect to a straight line connecting the first projecting rim portion and the ship body center line and has a front end and a rear end of a center line between the first projecting rim and the ship center line, And is curved upward in a concave shape with respect to a straight line connecting them,
Wherein the second flow path is curved upward in a concave shape with respect to a straight line connecting the first projecting rim portion and the second projecting rim portion, and the second flow path is formed between the first projecting rim portion and the second projecting rim portion Wherein the center line is curved in a concave upward direction with respect to a straight line connecting the front end and the rear end of the center line. The method according to claim 1,
Wherein the first flow path is curved upward in a concave shape with respect to a straight line connecting between the first projecting rim portions and a concave shape upwardly with respect to a straight line connecting the front end and the rear end of the center line between the first projecting rim portions As shown in FIG.
Wherein the second flow path is curved upward in a concave shape with respect to a straight line connecting the first projecting rim portion and the second projecting rim portion, and the second flow path is formed between the first projecting rim portion and the second projecting rim portion Wherein the center line is curved in a concave upward direction with respect to a straight line connecting the front end and the rear end of the center line. 4. The method according to any one of claims 1 to 3,
The first flow path is formed above the position 0.3 times below the planned draft from the planned waterline,
Wherein the second flow path is formed above the position 0.1 times below the planned draft from the planned waterline. 5. The method according to any one of claims 1 to 4,
Wherein the first flow path and the second flow path are formed rearward at a position 0.2 times the length between the waterlines from the aft waterline. 6. The method according to any one of claims 1 to 5,
The lower end of the first rear end protruding portion is located within a range from a position 0.2 times higher than the planned draft to the planned waterline from the planned waterline,
And the lower end of the second rear end protruding portion is located within a range from a position 0.3 times higher than the planned draft to the planned waterline from the planned waterline.
7. The method according to any one of claims 1 to 6,
A ship with a furd number of 0.2 to 0.4.

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