KR102170041B1 - A rudder and a ship having the rudder - Google Patents

Abstract

The present invention relates to a ship rudder and a ship including the same, which is provided at the rear of a propeller that is coupled to a stern to generate a propulsion force, and controls a propulsion direction of the ship, comprising: an upper rudder provided on a hull side; A lower rudder provided under the upper rudder; And a rudder bulb provided between the upper rudder and the lower rudder, wherein the rudder bulb is divided into two lines orthogonal to the cross-sectional area in the front and rear direction, and It is characterized in that a certain portion including one portion of the lower portion has a relatively small radius of curvature at least partially compared to the remaining portion.

Description

A rudder and a ship having the rudder

The present invention relates to a ship rudder and a ship including the same.

In general, in the case of a large ship, a method of advancing by using the flow of fluid generated when a propeller attached to the rear of the hull rotates is used. At this time, a rudder is attached to the rear of the propeller, and as the rudder rotates left and right, the direction of navigation is changed by adjusting the flow direction of the fluid.

In this way, in order to achieve a certain speed through rotation of the propeller, the engine must be driven using oil such as diesel. In this case, a large amount of oil is consumed and greenhouse gas is discharged, causing problems such as environmental destruction. .

Therefore, in recent years, various efforts have been made to reduce fuel consumption by reducing energy consumed during propulsion of a ship. In particular, IMO has discussed ways to reduce GHG emissions during ship operation, and is in the process of debating the standards and directions for fuel economy regulations.

As shipping companies joined in this movement, shipping companies began to pay attention to fuel-saving ships that could reduce the burden of fuel costs. In response to the needs of shipping companies, shipbuilders have been continuously researching and developing fuel-saving technologies that can reduce fuel consumption and reduce greenhouse gas emissions.

As an example of fuel-saving technology, an energy saving device (ESD: Energy Saving Device) that saves fuel while increasing propulsion efficiency by improving the shape of a ship's tail, propeller, rudder, etc. It is receiving attention, and these energy-saving supplementary devices have already been applied and used in a significant number of ships.

However, since such energy-saving additional devices increase the propulsion efficiency of the ship and increase the resistance on the one hand, research and development of energy-saving additional devices that can maximize propulsion efficiency while minimizing the increase in resistance are continuously made. Is losing.

Publication Patent Publication No. 10-2009-0049514 (20090518, published) Public Patent Publication No. 10-2014-0075928 (20140620, published) Public Patent Publication No. 10-2011-0007721 (20110125, published)

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to efficiently improve the leading edge of the upper rudder and to reduce the area ratio of the lower rudder and the upper rudder for a rudder composed of an upper and lower rudder. By improving, it is intended to provide a ship rudder and a ship including the same to maximize the steering performance using the wake generated by the propeller while controlling the flow in a stable state.

It is also an object of the present invention to provide a ship rudder capable of securing optimum steering efficiency by effectively controlling flow while suppressing an increase in resistance by improving a shape of a rudder bulb, and a ship including the same.

In addition, an object of the present invention is to provide a ship capable of preventing unnecessary resistance from being generated by preventing the flow of fluid rising on the lower surface of the transom by providing a wedge on the transom of the ship.

In the rudder for a ship according to an aspect of the present invention is provided at the rear of the propeller that is coupled to the stern to generate a propulsion force, in the rudder for adjusting the propulsion direction of the ship, the upper rudder provided on the hull side; A lower rudder provided under the upper rudder; And a rudder bulb provided between the upper rudder and the lower rudder, wherein the rudder bulb is divided into two lines orthogonal to the cross-sectional area in the front and rear direction, and It is characterized in that a certain portion including one portion of the lower portion has a relatively small radius of curvature at least partially compared to the remaining portion.

Specifically, the radius of curvature may be a distance between a central axis of the rudder bulb and a surface of the rudder bulb in a cross section in the front and rear direction.

Specifically, the predetermined portion may be a 180° portion including a portion of the upper side of the starboard, a portion of the upper side of the port, and a portion of the lower portion of the starboard in the cross-sectional area in the front and rear direction.

Specifically, the remaining portion may have a constant distance between the central axis and the surface.

Specifically, the radius of curvature may be reduced and then increased from one side connected to the other part to the other side connected to the other part based on the central axis.

Specifically, a portion of the predetermined portion in contact with the remaining portion may have the same radius of curvature as compared to the remaining portion.

Specifically, the rudder bulb may be positioned in parallel with the rotation axis of the propeller.

A ship according to an aspect of the present invention is characterized in that it includes the ship rudder.

A ship rudder and a ship including the same according to the present invention can reduce resistance and maximize steering performance by improving the shape of the leading edge and/or trailing edge of the upper and lower rudders constituting the rudder.

In addition, a ship rudder and a ship including the same according to the present invention can reduce vortex and increase propulsion efficiency by optimizing the shape of a rudder bulb provided to connect between the upper and lower rudders.

In addition, the ship according to the present invention can stabilize the flow of fluid by providing wedges on the left and right sides of the skeg on the lower surface of the transom, and guiding the fluid flowing along the lower surface of the transom downward.

1 is a perspective view of a ship rudder according to a first embodiment of the present invention.
2 is a perspective view of a ship rudder according to a second embodiment of the present invention.
3 is a perspective view of a ship rudder according to a third embodiment of the present invention.
4 is a pressure and flow distribution diagram of a ship rudder according to a third embodiment of the present invention.
5 is a perspective view of a ship rudder according to a fourth embodiment of the present invention.
6 is a pressure and flow distribution diagram of a ship rudder according to a fourth embodiment of the present invention.
7 is a front view and a side view of a ship rudder according to a fifth embodiment of the present invention.
8 is a perspective view of a ship rudder according to a sixth embodiment of the present invention.
9 is a pressure and flow distribution diagram of a ship rudder according to a sixth embodiment of the present invention.
10 is a front view and a side view of a conventional ship rudder.
11 is a pressure and flow distribution diagram of a conventional ship rudder.
12 is a front view and a side view of a ship rudder according to a seventh embodiment of the present invention.
13 is a pressure and flow distribution diagram of a ship rudder according to a seventh embodiment of the present invention.
14 is a front view and a side view of a ship rudder according to an eighth embodiment of the present invention.
15 is a pressure and flow distribution diagram of a ship rudder according to an eighth embodiment of the present invention.
16 is a front view of a ship rudder according to the present invention.
17 is a graph showing thrust efficiency of ship rudders according to the present invention.
18 is a front view of a rudder bulb in a ship rudder according to a ninth embodiment of the present invention.
19 is a front view of a rudder bulb in a ship rudder according to a tenth embodiment of the present invention.
20 is a front view and a side view of a rudder bulb in a ship rudder according to an eleventh embodiment of the present invention.
21 is a side view of a ship according to a twelfth embodiment of the present invention.
22 is a rear view of a ship according to a thirteenth embodiment of the present invention.
23 is a cross-sectional view taken along AA′ of FIG.
24 is a performance graph of a ship according to a thirteenth embodiment of the present invention.

Objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings. In adding reference numerals to elements of each drawing in the present specification, it should be noted that, even though they are indicated on different drawings, only the same elements are to have the same number as possible. In addition, in describing the present invention, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, since the present invention relates to a ship rudder and a ship including the same, it should be noted that the ship of the present invention may be a ship having a ship rudder of the embodiments described below.

1 is a perspective view of a ship rudder according to a first embodiment of the present invention.

Referring to FIG. 1, a ship rudder 2 according to a first embodiment of the present invention includes an upper rudder 10, a lower rudder 20, and a rudder bulb 30.

At this time, the ship rudder 2 of the present invention may be provided at the rear of the propeller 100 which is installed on the stern 3 to generate a propulsion force. The propeller 100 is installed on the stern boss of the stern 3 and may be composed of a hub 110 rotatably connected to the stern boss, and a wing 120 radially coupled to the hub 110. In addition, at the rear of the hub 110, a cap 130 may be provided that is fixed to the stern 3 and prevents retraction of the hub 110 when the hub 110 rotates.

When the propeller 100 rotates, an inflow flow occurs from the front to the rear of the propeller 100 in the hull. At this time, the inflow flow is strongly discharged while passing through the propeller 100 and may flow into the ship rudder 2 as a wake.

The ship's rudder (2) receives the wake, but the wake flow is biased to the port so that the ship (1) turns to the left, or the wake flow is biased to the starboard so that the ship (1) turns to the right. can do. To this end, the ship rudder 2 may be rotatably provided on the stern 3, and specifically, may be connected to the lower part of the transom through the skeg 40.

The upper rudder 10 is provided on the hull side. When the ship rudder 2 of the present invention is viewed in the vertical direction, the upper part may be defined as the upper rudder 10 and the lower part may be defined as the lower rudder 20. However, the upper rudder 10 and the lower rudder 20 may not be clearly distinguished. This is because the surface of the upper rudder 10 and the surface of the lower rudder 20 may be smoothly connected.

The upper rudder 10 has a leading edge 11 and a trailing edge 12. The upper rudder 10 may have an airfoil-shaped cross section, and the distance from the point where the maximum thickness is formed to the leading edge 11 may be shorter than the distance from the point to the trailing edge 12.

The leading edge 11 of the upper rudder 10 refers to a point at which the wake generated by the propeller 100 is introduced, and the trailing edge 12 of the upper rudder 10 is the upper rudder 10 ) Can mean the point of exit from.

The leading edge 11 and the trailing edge 12 may appear as lines on the front and rear surfaces of the upper rudder 10, respectively. However, the trailing edge 12 may appear as a clear line as the rear of the upper rudder 10 is sharpened, but the leading edge 11 is formed in a smooth curved surface in front of the upper rudder 10, so that It may not appear clearly. In this case, the leading edge 11 may be defined as a line connecting the most front end points in each cross section of the upper rudder 10 vertically. The same is true for the trailing edge 12.

The upper rudder 10 is provided on the hull side and may be connected to the stern 3 by a skeg 40. At this time, the skeg 40 may be fixed to the stern 3, while the upper rudder 10 may be provided to be rotatable with respect to the skeg 40.

The upper rudder 10 may be located at the upper part about the rotation axis of the propeller 100, and when the propeller 100 rotates, the wake generated above the rotation shaft may be transmitted. In fact, since it is the flow located above the shaft of the propeller 100 in the wake that affects the steering performance, the area of the upper rudder 10 may be relatively larger than the area of the lower rudder 20. This will be described again below.

The upper rudder 10 may have a shape in which the left and right widths decrease from the top to the bottom. That is, the front cross-section of the upper rudder 10 at the point where the left and right widths become maximum may be inverted trapezoidal shape.

The lower rudder 20 is provided under the upper rudder 10. The lower rudder 20 may be connected to the lower end of the upper rudder 10, and as described above, the upper rudder 10 and the lower rudder 20 may be connected at least partially indistinguishable. Of course, when at least one of the leading edges 11 and 21 of the upper rudder 10 and the lower rudder 20 is deflected, the upper rudder 10 and the lower rudder 20 are at least partially displaced from each other. Can be distinguished.

The lower rudder 20 may be divided up and down with the upper rudder 10 based on the rotation axis of the propeller 100, and a rudder bulb 30 may be provided between the upper rudder 10 and the lower rudder 20. have. The rudder bulb 30 may be provided to cover a portion that is shifted when the upper rudder 10 and the lower rudder 20 are shifted from each other.

The lower rudder 20 may have the same/similar cross section as the upper rudder 10. That is, the lower rudder 20 may also be in the form of an airfoil including the leading edge 21 and the trailing edge 22. In addition, the lower rudder 20 may also have a shape in which the left and right widths decrease from the top to the bottom.

The rudder bulb 30 is provided between the upper rudder 10 and the lower rudder 20. The rudder bulb 30 may be provided so that the central axis 31 is parallel to the rotational axis of the propeller 100, and has an effect of reducing vortex that may be generated from the cap 130 of the propeller 100. I can.

To this end, the rudder bulb 30 may have a curved shape in which the front end is convex in the direction of the propeller 100, but a plane may be partially formed. On the other hand, the rear end of the rudder bulb 30 may have a shape that is relatively sharper than the front end so as to smoothly guide the flow of the fluid.

The shape of the rudder bulb 30 of the present invention will be described in detail in another embodiment.

The ship rudder 2 of the present invention may be connected to the ship 1 by a skeg 40. The skeg 40 is a structure connecting the upper rudder 10 to the hull, and may be fixed to the hull. At this time, the ship rudder 2 including the upper rudder 10 based on the skeg 40 can rotate, and the skeg 40 has a rudder shaft (not shown) for rotation of the ship rudder 2 Can be penetrated.

In addition, a steering gear room (not shown) that controls the rotation of the ship's rudder 2 may be provided in the vicinity of the skeg 40 within the hull, and navigation of the ship 1 by controlling the rotation of the rudder shaft in the steering gear room You can adjust the direction. Of course, the present invention does not limit the arrangement of the steering gear room as described above, but the steering gear room may be connected to a bridge or the like that controls the navigation of the ship 1.

Hereinafter, the leading edges 11 and 21 of the upper rudder 10 and the lower rudder 20 according to the present invention will be described.

The leading edge 11 of the upper rudder 10 may protrude forward compared to the leading edge 21 of the lower rudder 20. At this time, since the trailing edge 12 of the upper rudder 10 and the trailing edge 22 of the lower rudder 20 may be provided vertically, the leading edge 11 of the upper rudder 10 is the lower rudder 20 When protruding forward compared to the leading edge 21 of ), the area of the upper rudder 10 may be larger than the area of the lower rudder 20.

The leading edge 11 of the upper rudder 10 may be provided to be inclined forward from the top to the bottom. At this time, as mentioned above, the left and right widths of the upper rudder 10 may decrease from top to bottom, but the cross-sectional area of the upper rudder 10 may be formed to increase from top to bottom.

That is, the upper rudder 10 may be formed such that the leading edge 11 inclines forward from the top to the bottom, and the cross-sectional area increases from the top to the bottom, and the cross-sectional area decreases from the top to the bottom. It can be formed to increase from to the bottom.

However, the cross-sectional area of the upper rudder 10 may not increase linearly from the top to the bottom due to a decrease in the left and right width even if the leading edge 11 is provided inclined. That is, the cross-sectional area of the upper rudder 10 may increase non-linearly from the top to the bottom.

At this time, the cross-sectional area of the upper rudder 10 may be formed to a maximum in the rotation axis of the propeller 100. The point at which the cross-sectional area of the upper rudder 10 is maximum may be a point of the maximum cross-sectional area in the ship rudder 2 including the upper rudder 10 and the lower rudder 20 except for the rudder bulb 30.

In this way, by forming a point in which the cross-sectional area is maximized in the ship rudder 2 is parallel to the rotational axis of the propeller 100, the present invention can maximize the steering performance and reduce the resistance.

The trailing edges 12 and 22 of the upper rudder 10 and the lower rudder 20 are continuously connected vertically, and the left and right widths are continuously decreased from the top of the upper rudder 10 to the bottom of the lower rudder 20. In this case, the fact that the maximum point of the cross-sectional area is formed in a position parallel to the rotational axis of the propeller 100 means that the distance between the propeller 100 and the ship rudder 2 is the minimum at the rotational axis point of the propeller 100 I can.

The distance between the propeller 100 and the ship rudder 2, in particular, the distance between the propeller 100 and the ship rudder 2 at the rotational axis point of the propeller 100, the closer the steering performance may be improved. Therefore, in the present invention, even if the entire ship rudder 2 is not installed close to the propeller 100, the cross-sectional area is maximized at a point parallel to the rotational axis of the propeller 100 in the ship rudder 2, and partially propeller 100 ), you can increase the steering performance.

When the leading edge 11 of the upper rudder 10 is provided as described above, the leading edge 21 of the lower rudder 20 may be formed in a vertical vertical direction. In this case, the difference between the lower sectional area of the upper rudder 10 and the upper sectional area of the lower rudder 20 may be relatively larger than the difference between the upper sectional area of the upper rudder 10 and the upper sectional area of the lower rudder 20.

In addition, when the upper cross-sectional area of the lower rudder 20 is smaller than the upper cross-sectional area of the upper rudder 10 even though the lower cross-sectional area of the upper rudder 10 is larger than the upper cross-sectional area, When the upper end of 20 is connected, the lower part of the upper rudder 10 may be exposed downward. In order to cover this, the present invention may provide a rudder bulb 30.

As the upper rudder 10 is enlarged compared to the lower rudder 20 as described above, the side area of the upper rudder 10 may be 1.5 to 3 times that of the lower rudder 20. As described above, the wake that affects the steering is a wake that occurs at the top of the rotating shaft of the propeller 100. Accordingly, the present invention can enlarge the area of the upper rudder 10 receiving the wake that affects steering compared to the prior art, and reduce the area of the lower rudder 20 receiving the wake less affecting the steering compared to the prior art. .

In this case, the upper rudder 10 may have the leading edge 11 protrude forward compared to the leading edge 21 of the lower rudder 20, as shown in the drawing, or, unlike the drawing, the upper rudder 10 The trailing edge 12 may protrude rearward compared to the trailing edge 22 of the lower rudder 20.

In addition, even if the side area of the upper rudder 10 is enlarged, the upper rudder 10 may not be enlarged more than the skeg 40. That is, the leading edge 11 of the upper rudder 10 having an enlarged area may be connected to the leading edge 41 of the skeg 40. Specifically, the lower end of the leading edge 41 of the skeg 40 may be connected to the upper end of the leading edge 11 of the upper rudder 10. To this end, the skeg 40 may be enlarged together as the upper rudder 10 is enlarged.

At this time, the trailing edge 41 of the skeg 40 may also be connected to the trailing edge 12 of the upper rudder 10, but the trailing edge 41 and the upper rudder 10 of the skeg 40 The trailing edge 12 of the upper rudder 10 and the trailing edge 12 of the upper rudder 10 are connected vertically and vertically, or as at least a part of the trailing edge 41 of the skeg 40 is formed to be inclined back and forth. It can be connected to be bent.

Of course, the leading edge 41 of the skeg 40 is provided to be connected to the leading edge 11 of the upper rudder 10, and the leading edge 21 of the lower rudder 20 is the leading edge of the skeg 40. It may be provided to be retracted rearward than the edge 41.

As the present invention reduces the area of the lower rudder 20 and enlarges the area of the upper rudder 10, the torque generated by the lower rudder 20 when the ship rudder 2 rotates with respect to the rudder axis decreases. When the propeller 100 rotates, the steering performance using the wake may not be reduced.

Accordingly, the present invention can significantly reduce the amount of fuel consumed for steering by reducing the rotation torque by the rudder shaft while sufficiently securing the steering performance.

Hereinafter, a relationship between the leading edge 11 of the upper rudder 10 and the rudder bulb 30 will be described.

The leading edge 11 of the upper rudder 10 may protrude forward compared to the leading edge 21 of the lower rudder 20 as described above, wherein the leading edge 11 of the upper rudder 10 is a rudder bulb It can be located within a preset range in the front and rear directions of (30).

That is, when the present invention includes the rudder bulb 30 to cover a portion where the upper rudder 10 and the lower rudder 20 are misaligned, the leading edge 11 of the upper rudder 10 is at least partially rudder bulb ( 30) can be provided adjacent to the front end.

At this time, the proximity degree may be indicated that the preset range is 0.1 to 1 m. Of course, the preset range may be 0, and in this case, the front end of the rudder bulb 30 and the leading edge 11 of the upper rudder 10 may be placed at the same position.

The front and rear distance between the front end of the rudder bulb 30 and the leading edge 11 of the upper rudder 10 is the front and rear distance between the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 It can be relatively smaller than the distance. For example, the front and rear distance between the front end of the rudder bulb 30 and the leading edge 11 of the upper rudder 10 is between the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 It may be within 0.5 of the front and rear distance.

Hereinafter, a twisting of the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 will be described.

At least one of the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 may be vertically deflected from side to side. That is, when viewed from the front, the leading edge 11 of the upper rudder 10 is arranged vertically while being deflected to the port or starboard, and the leading edge 21 of the lower rudder 20 is vertically deflected to the starboard or the port. It can be provided in any direction. Of course, the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 may be deflected in different directions, and/or may be deflected in the same direction, but the degree of deflection may be different. .

On the other hand, at least one of the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 may be inclined to the left and right. That is, when viewed from the front, the leading edge 11 of the upper rudder 10 may appear as an oblique line whose upper side is deflected to one of the port and starboard sides and the degree of deflection decreases toward the bottom, and the leading edge of the lower rudder 20 21) may appear as a diagonal line with the upper side being deflected to one of the starboard and port sides, and the degree of deflection decreases toward the bottom.

Of course, the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 change the direction of deflection from the top to the bottom, and/or the degree of deflection decreases or increases. It can appear in various ways. That is, for example, in the leading edge 11 of the upper rudder 10, the upper end may be deflected to the port and the lower end may be deflected to the center or the starboard, or the upper end may be positioned at the center and the lower end may be deflected to the starboard.

As described above, it should be noted that the twisting of the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 may appear in various forms, and is not limited to the examples described above.

Hereinafter, the trailing edges 12 and 22 of the upper rudder 10 and the lower rudder 20 according to the present invention will be described.

The trailing edge 12 of the upper rudder 10 may be provided vertically in a vertical direction. That is, when viewed from the lateral direction, the trailing edges 12 of the upper rudder 10 may be arranged vertically.

In addition, the trailing edge 22 of the lower rudder 20 may also be provided vertically in a vertical direction, and may be continuous with the trailing edge 12 of the upper rudder 10. That is, the trailing edge 12 of the upper rudder 10 and the trailing edge 22 of the lower rudder 20 may be parallel to each other.

Of course, the contents described above for the leading edge 11 of the upper rudder 10 may also be applied to the trailing edge 12. That is, the trailing edge 12 of the upper rudder 10 may deviate from the trailing edge 22 of the lower rudder 20, and this may be variously displayed in front and rear and/or left and right.

2 is a perspective view of a ship rudder according to a second embodiment of the present invention.

Referring to FIG. 2, in the ship rudder 2 according to the second embodiment of the present invention, only the leading edge 21 of the lower rudder 20 appears differently when compared to the first embodiment. Hereinafter, a description will be made based on differences in this embodiment compared to other embodiments, and portions not described may be replaced with contents described in other embodiments. This is the same for the rest of the embodiments to be described below.

In this embodiment, the leading edge 21 of the lower rudder 20 may appear in an oblique direction rather than a vertical direction. That is, the leading edge 21 of the lower rudder 20 may be provided to be inclined rearward from the top to the bottom, as opposed to the leading edge 11 of the upper rudder 10.

In this case, the cross-sectional area of the ship's rudder 2 becomes maximum near the axis of rotation of the propeller 100 where the upper rudder 10 and the lower rudder 20 are separated, and decreases toward the top of the upper rudder 10, and the lower As it goes to the bottom of the rudder 20, it may also decrease.

In this embodiment, the rudder bulb 30 may also be provided. In this embodiment, a sharp decrease in cross-sectional area can be prevented from the rudder bulb 30 to the lower end, so that the flow of the flow can be guided more efficiently.

3 is a perspective view of a ship rudder according to a third embodiment of the present invention, and FIG. 4 is a pressure and flow distribution diagram of a ship rudder according to a third embodiment of the present invention.

3 and 4, in the ship rudder 2 according to the third embodiment of the present invention, the leading edge 11 of the upper rudder 10 may appear differently when compared to the first embodiment.

Like the leading edge 21 of the lower rudder 20, the leading edge 11 of the upper rudder 10 may be provided in a vertical direction. That is, the leading edge 11 of the upper rudder 10 may not be inclined in the front-rear direction even if it goes from the top to the bottom.

At this time, the leading edge 11 of the upper rudder 10 may be located within a preset range in the front and rear directions of the rudder bulb 30, which is from the top to the bottom of the leading edge 11 of the upper rudder 10. Can be applied. Previously, in the first embodiment, the lower end of the leading edge 11 of the upper rudder 10 is located within the front end and the preset range of the rudder bulb 30, but in this embodiment, the leading edge 11 of the upper rudder 10 The entire rudder bulb 30 may be located in the front end and within a preset range. Of course, all of the leading edges 11 of the upper rudder 10 may be provided parallel to the front end of the rudder bulb 30 in all directions.

5 is a perspective view of a ship rudder according to a fourth embodiment of the present invention, and FIG. 6 is a pressure and flow distribution diagram of a ship rudder according to a fourth embodiment of the present invention.

5 and 6, the rudder 2 for a ship according to the fourth embodiment of the present invention may be different from other embodiments in the shape of the rudder bulb 30.

The rudder bulb 30 is positioned parallel to the rotational axis of the propeller 100, but may be provided in a vertical asymmetric shape. That is, in the rudder bulb 30, the central axis 31 is parallel to the rotational axis of the propeller 100, but the upper surface is convex upward, and at least a portion of the lower surface may be convex upward.

The fact that the central axis 31 of the rudder bulb 30 is parallel to the rotation axis of the propeller 100 means that the center of the cross section at the point where the cross-sectional area is the largest in the front-rear direction from the rudder bulb 30 is parallel to the rotation axis of the propeller 100 It can mean that.

On the other hand, the rudder bulb 30 may be convex downward from the lower surface to the front side surface based on the point at which the cross-sectional area in the front-rear direction is maximum. That is, the front side surface of the lower surface may be provided to be symmetrical with the upper surface based on the point. Accordingly, the center of the cross-sectional area in the front-rear direction in front of the point may be provided parallel to the rotation axis of the propeller 100.

That is, the lower surface to the rear surface may be convex upward based on the point. At this time, in the rudder bulb 30, the center of the cross-sectional area in the front-rear direction from the rear of the point may be skewed upward relative to the rotation axis of the propeller 100.

As the present embodiment improves the shape of the rudder bulb 30 in this way, the present embodiment can increase thrust and lower the torque. This can be confirmed through the comparison between Table 1 and FIG. 4 and FIG. 6 below.

The table below shows the measurement of torque and thrust for various types of ship rudders (2) when the ship speed (Vs) is 21.0 knots and the draft is 16.0 m. CASE 1 is a general conventional rudder, CASE 2 is a twist rudder in which the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 are vertically deflected to port and starboard, respectively, and CASE 3 is 3 is a third embodiment of the present invention, CASE 4 is a fourth embodiment of the present invention in which the shape of the rudder bulb 30 is improved.

CASE RPS T[N] Q[N-m] DIFF.N*Q One 7.165 54.477 2.500 0.00% 2 7.135 53.786 2.471 -1.57% 3 7.086 53.693 2.449 -3.12% 4 7.083 53.371 2.439 -3.56%

Looking at the tables and drawings, when the propeller 100 rotates in one direction, different flows occur on the left and right sides of the ship rudder 2, respectively. For example, when the propeller 100 rotates clockwise when viewed from behind, a pressure surface is formed on the upper port and the lower starboard of the ship rudder 2, and a suction surface is formed on the lower port and the upper starboard.

According to such a pressure distribution, peeling occurs in the wake transmitted from the propeller 100 to the ship rudder 2, and thus resistance increases, thereby deteriorating the steering performance of the ship rudder 2.

However, looking at FIG. 6 compared to FIG. 4, in this embodiment, by improving the shape of the rudder bulb 30 as shown in the drawing, it is possible to reduce the pressure deviation occurring in the left and right and up and down, and through this, as shown in Table 1 Likewise, thrust improvement and torque reduction effects can be secured.

7 is a front view and a side view of a ship rudder according to a fifth embodiment of the present invention.

Referring to FIG. 7, in the ship rudder 2 according to the fifth embodiment of the present invention, the leading edge 11 of the upper rudder 10 may be different compared to other embodiments.

The leading edge 11 of the upper rudder 10 may be inclined to the left and right, and at this time, the leading edge 11 may be bent at least once to change the inclined direction. That is, the leading edge 11 of the upper rudder 10 may at least partially have a ">" shape or a "<" shape when viewed from the front.

Specifically, the leading edge 11 of the upper rudder 10 includes a first leading edge 111 extending from the upper end of the upper rudder 10 to a certain point, and a second leading edge 111 extending from a certain point to the lower end of the upper rudder 10. It may include a leading edge 112.

At this time, one of the first leading edge 111 and the second leading edge 112 may be inclined from the port to the starboard direction from the bottom to the top, and the other is inclined from the starboard to the port side from the bottom to the top. I can lose.

As an example, as shown in the drawing, when viewed from the front, the second leading edge 112 on the lower side is inclined from the starboard to the port from the bottom to the top. Conversely, the first leading edge 111 on the upper side is When viewed from the bottom to the top, it may be inclined from port to starboard.

In this case, the first leading edge 111 and the second leading edge 112 may have the same absolute value of the inclination angle compared to the vertical direction. However, a certain point may be provided biased to the top of the top and bottom of the upper rudder 10, and the length of the first leading edge 111 may be shorter than the length of the second leading edge 112. The left and right widths of the first leading edge 111 may be smaller than the left and right widths of the second leading edge 112.

In addition, a predetermined point at which the first leading edge 111 and the second leading edge 112 are bent and connected may be skewed to the port or starboard, and in the drawing, it is illustrated as being skewed to the port. Of course, in the present invention, a certain point may be located in the center, and the first leading edge 111 is inclined from the center to the starboard from the bottom to the top, and the second leading edge 112 is from the starboard to the bottom to the top. Can be sloped to the center.

At this time, the leading edge 21 of the lower rudder 20 may be obliquely deflected to the left or right or vertically deflected to the left and right. Of course, the leading edge 21 of the lower rudder 20 may be formed like the leading edge 11 of the upper rudder 10 or may be provided without being deflected.

8 is a perspective view of a ship rudder according to a sixth embodiment of the present invention, and FIG. 9 is a pressure and flow distribution diagram of a ship rudder according to a sixth embodiment of the present invention.

8 and 9, the ship rudder 2 according to the sixth embodiment of the present invention may have an inclined surface 23 formed on a lower surface of the lower rudder 20. That is, the lower surface of the lower rudder 20 may have an inclined surface 23 inclined upward from the front to the rear, and at this time, the inclined surface 23 may be formed on at least a portion of the lower surface of the lower rudder 20 .

At this time, the trailing edge 12 of the lower rudder 20 may be shortened when compared to the case where the inclined surface 23 is not present. That is, the lower rudder 20 may have a chamfer formed at the rear lower corner when viewed from the side.

Among the wakes of the propeller 100, not all wakes flowing into the ship's rudder 2 are effective for steering. That is, some of the area of the ship's rudder 2 does not have a significant effect on the steering. In particular, the rear lower edge of the lower rudder 20, as in the present embodiment, hardly affects the steering performance.

Therefore, in this embodiment, the area of the lower rudder 20 can be partially reduced while forming the inclined surface 23 to maintain the steering performance as it is, and through this, the vortex flow that can occur at the rear lower edge of the lower rudder 20 By suppressing the flow, it is possible to stably flow.

10 is a front view and a side view of a conventional ship rudder, FIG. 11 is a pressure and flow distribution diagram of a conventional ship rudder, and FIG. 12 is a front view and a side view of a ship rudder according to a seventh embodiment of the present invention, and FIG. 13 is a pressure and flow distribution diagram of a ship rudder according to a seventh embodiment of the present invention.

14 is a front view and a side view of a ship rudder according to an eighth embodiment of the present invention, and FIG. 15 is a pressure and flow distribution diagram of a ship rudder according to an eighth embodiment of the present invention.

10 and 11, a conventional ship rudder (the leading edge 11 of the upper rudder 10 and the leading edge 21 of the lower rudder 20 are vertically deflected to the port side and starboard side, respectively) In the case of, it can be seen that when the propeller 100 rotates in one direction, the pressure deviation that appears above the starboard side of the ship rudder is significant.

On the other hand, referring to FIGS. 12 and 13, the ship rudder 2 according to the seventh embodiment of the present invention is near the rotation axis of the propeller 100, which is a part where the upper rudder 10 and the lower rudder 20 are connected. In, by providing the rudder bulb 30 to rectify the flow to remove the vortex of the hub 110, the flow can be stabilized.

In addition, in this embodiment, the leading edge 11 of the upper rudder 10 is tilted forward from the top to the bottom and deflected to one side, thereby suppressing the pressure drop occurring in the upper right of the ship rudder 2 Can be reduced.

Referring to FIGS. 14 and 15, the rudder 2 for a ship according to the eighth embodiment of the present invention can effectively rectify the flow by changing the shape of the rudder bulb 30 to that of other embodiments. The rudder bulb 30 according to the present embodiment may have a water droplet shape, and a relatively sharp portion may be provided at the front and a relatively curved portion may be provided at the rear.

At this time, the relatively sharp portion may form a vertex forward or may form a curved surface, but the relatively sharp portion may mean that the radius of curvature is smaller than that of a relatively curved portion.

The rudder bulb 30 may be rotationally symmetric with respect to the central axis 31, and the central axis 31 of the rudder bulb 30 may be parallel to the rotation axis of the propeller 100. In addition, the rudder bulb 30 may be provided so that the point at which the cross-sectional area in the front-rear direction is maximum is biased to the rear end of the front end and the rear end.

That is, in the rudder bulb 30 of the present embodiment, a degree of decrease in cross-sectional area toward a front end may be relatively smaller than a degree of decrease in cross-sectional area toward a rear end based on a point at which the cross-sectional area in the front and rear direction becomes maximum.

When the rudder bulb 30 is provided in the form of water droplets as described above, the present embodiment can suppress a pressure drop appearing above the starboard side of the ship rudder 2 as shown in FIG. 15 compared to FIG. The flow is prevented from being disturbed by the bulb 30 and the flow can be concentrated and flowed from the side of the ship rudder 2, so that the steering performance can be improved.

16 is a front view of the ship rudders according to the present invention, Figure 17 is a graph showing the thrust efficiency of the ship rudders according to the present invention.

18 is a front view of a rudder bulb in a ship rudder according to a ninth embodiment of the present invention, and FIG. 19 is a front view of a rudder bulb in a ship rudder according to a tenth embodiment of the present invention.

When the propeller 100 rotates in one direction (for example, it rotates clockwise when viewed from the back), the wake flowing into the ship rudder 2 by the rotation of the propeller 100 is bound to appear as asymmetric left and right.

Therefore, as shown in FIGS. 16 and 17, depending on the shape of the cross section of the rudder bulb 30, whether or not the thrust is improved is bound to be different. Through this, in the present invention, it is possible to confirm which portions of the rudder bulb 30 are helpful in improving thrust and which portions are not helpful in improving thrust.

It can be seen clearly in (d) and (e) which part of the rudder bulb 30 is effective on the left (left when viewed from the front, and starboard) and right (right when viewed from the front, which is the port). That is, as shown in FIG. 17, it can be seen that the port portion of the rudder bulb 30 is effective.

In addition, it is possible to compare (f) and (g) with respect to which part of the upper side and the lower side is effective, which did not show a significant difference in whether or not the thrust was improved.

However, when comparing (b) and (e), it can be seen that the lower left (lower starboard) of the rudder bulb 30 did not have a significant effect on the thrust reduction, so in the end, the rudder bulb 30 You can see that the part that didn't help is the upper left (top starboard). This means the upper left side (upper starboard) from the front when the rudder bulb 30 divides the cross-sectional area in the front and rear direction into two orthogonal lines.

Referring to FIG. 18, when the rudder 2 for a ship according to the ninth embodiment of the present invention divides the cross-sectional area in the front and rear directions in the rudder bulb 30 in consideration of these results, one side of the port or starboard from the top The radius of curvature of a certain portion 32 including a portion on the other side from the top and a portion on one side from the bottom was made to have a relatively large radius of curvature at least partially compared to the remaining portion 33.

As an example, the rudder bulb 30 of this embodiment defines a certain part 32 including an upper starboard, a part of an upper port, and a lower part of the starboard, and a radius of curvature of the certain part 32 is greater than that of the rest 33 Formed large. Particularly, the certain portion 32 may be composed of a portion at 90 degrees above the starboard, a portion at 45 degrees above the port, and a portion at 45 degrees below the starboard.

That is, the rudder bulb 30 has a convex degree, which is the distance from the front-rear section to the surface of the rudder bulb 30 based on the central axis 31, to be formed relatively small in a certain portion 32 compared to the remaining portion 33. I can. This is to ensure that the rudder bulb 30 is formed around a portion advantageous for improving thrust.

However, the rudder bulb 30 may be cut off only a portion that is not very helpful for thrust, but in this case, as the cut surface is formed, the fluid may be separated, resulting in an increase in resistance. This can be seen by comparing (h) and (j) in FIG. 17.

That is, according to the present invention, the portion of the rudder bulb 30 that is not very helpful to thrust (top of the starboard) is not completely cut out, but instead is reduced in size, thereby suppressing an increase in resistance and inducing thrust improvement.

At this time, the remaining portion 33 may have a constant distance between the central axis 31 and the surface, and the predetermined portion 32 is connected to the remaining portion 33 based on the central axis 31 and the remaining portion 33 ), the radius of curvature may increase and decrease as you go to the other side connected to ).

This means that the portion of the portion 32 that contacts the remaining portion 33 has the same radius of curvature as that of the remaining portion 33 in order to smoothly connect the surface of the rudder bulb 30, but the portion 32 This is because the radius of curvature increases in the middle of ).

Or the present invention, referring to FIG. 19, the upper starboard portion 32, which is a portion of the rudder bulb 30 that is not very helpful for thrust, is defined as a predetermined portion 32, and the predetermined portion 32 which is the upper starboard portion is the remaining portion 33 ), the radius of curvature can be made relatively large, at least partially.

In this embodiment, the certain part 32 may be a part of the upper part of the starboard at 90 degrees, and the certain part 32 may be relatively small when compared to the embodiment described above. That is, in this embodiment, a certain part 32 is in the range of about 90 degrees with respect to the central axis 31 of the rudder bulb 30, and in the above-described embodiment, the certain part 32 is the central axis of the rudder bulb 30 It may be in the range of about 180 degrees based on (31).

Of course, the present invention is not limited to a certain portion 32 in which the radius of curvature is partially increased to the 90 degree range and 180 degree range as described above, and the certain part 32 greatly helps to improve thrust in the rudder bulb 30 It may be in the range of 90 degrees to 180 degrees including the top of the starboard that does not become.

20 is a front view and a side view of a rudder bulb in a ship rudder according to an eleventh embodiment of the present invention.

Referring to FIG. 20, the rudder 2 for a ship according to the eleventh embodiment of the present invention may form a groove 34 in the rudder bulb 30.

At this time, the groove 34 may be inwardly recessed in the surface of the rudder bulb 30, and the groove 34 may be a cut sphere shape or a shape extending in the front and rear direction of the rudder bulb 30. At this time, the grooves 34 may have a shape having a spiral shape while extending in the front and rear direction of the rudder bulb 30, and may be provided in plural and disposed to be spaced apart from each other.

In addition, the grooves 34 are provided in plural and may be evenly arranged based on the cross-section in the front-rear direction of the rudder bulb 30. As illustrated in the front view of FIG. 20, the grooves 34 may be disposed at 120 degree intervals based on the central axis 31 of the rudder bulb 30.

Further, the shape of the groove 34 is not limited to the above and may be provided in various ways, but the groove 34 may be provided in the rudder bulb 30 in a left and right asymmetric manner. This embodiment forms the left and right asymmetric grooves 34 in the rudder bulb 30 because the rotational flow of the propeller 100 is asymmetric left and right.

When the propeller 100 rotates in one direction, the wake flowing into the ship's rudder 2 appears as left and right asymmetric. Therefore, even if the ship rudder 2 is set to 0 degrees, as the flow of the fluid flowing in each of the port and starboard sides of the ship rudder 2 is different from each other, the ship 1 may not go straight and may turn at a certain angle. In this case, in order for the ship 1 to go straight, the ship rudder 2 must be set at an angle other than 0 degrees and sail.

However, in this embodiment, the groove 34 is provided in the rudder bulb 30 in a left-right asymmetric manner, so that the wake of the propeller 100 may be offset from the left-right asymmetric appearance. That is, the groove 34 is in a state in which the upper rudder 10 and the lower rudder 20 are not rotated, and when the ship rudder 2 is placed at 0 degrees, the asymmetrical wake is the upper rudder 10 and the lower rudder. Even if it enters (20), the hull can be made to go straight.

Therefore, in this embodiment, a groove 34 is provided in the rudder bulb 30 to form the surface of the rudder bulb 30 in a left and right asymmetric manner, and through this, the asymmetry of the wake of the propeller 100 is alleviated, Even if the rudder 2 is positioned at 0 degrees and the propeller 100 transmits a wake, which is a rotating flow, to the ship rudder 2, it is possible to make the ship 1 go straight.

21 is a side view of a ship according to a twelfth embodiment of the present invention.

Referring to FIG. 21, a ship 1 according to a twelfth embodiment of the present invention includes a rudder bulb 30 and a cap 130.

The rudder bulb 30 and the cap 130 may be convex in a direction in which surfaces facing each other face each other. At this time, the rudder bulb 30 and the cap 130 may be spaced apart with a gap 36, but the gap 36 may be formed very narrow (for example, the gap 36 is 0.1 to 1 m).

If the gap 36 is narrowed in this way, it is possible to prevent the fluid from being disturbed until the wake of the propeller 100 flows into the ship rudder 2. That is, as the ship rudder 2 is disposed closer to the propeller 100, the steering performance improves. However, since the rudder bulb 30 moves when the ship's rudder 2 rotates, the cap 130 is fixed to the stern 3, so the rudder bulb 30 and the cap 130 have a certain gap ( 36) can be formed.

In this embodiment, in order to narrow the gap 36 between the rudder bulb 30 and the cap 130, the rudder bulb 30 includes a bulb extension 35 and the cap 130 is a cap extension ( 131) can be included. That is, the rudder bulb 30 includes a bulb extension portion 35 extending forward so that a cross-sectional area is uniformly or linearly decreased in front of the ship rudder 2, and the cap 130 is at the rear of the propeller 100 It may include a cap extension 131 extending rearward so that the cross-sectional area decreases linearly.

At this time, the front of the rudder bulb 30 is provided in front of the bulb extension 35, and the rear of the cap 130 is provided at the rear of the cap extension 131, and the front of the rudder bulb 30 The rear surface of the cap 130 may be spaced apart from each other with a gap 36.

At this time, the distance between the front end of the bulb extension part 35 and the rear end of the cap extension part 131 may be 2 to 5 times the gap 36, and for example, may be 0.2 to 1 m. In this way, the distance between the front end of the bulb extension portion 35 and the rear end of the cap extension portion 131 is not large, the front surface of the rudder bulb 30 and the rear surface of the cap 130 are curved surfaces having a relatively large radius of curvature. It is to minimize the gap 36 by making them face each other (closer to the plane) or while having a plane. At this time, the front surface of the rudder bulb 30 and the rear surface of the cap 130 may be formed as curved surfaces having the same radius of curvature.

As described above, in this embodiment, while minimizing the gap 36 between the rudder bulb 30 and the cap 130, the front surface of the rudder bulb 30 and the rear surface of the cap 130 have a shape close to the plane. By being arranged very closely, it is possible to ensure that the fluid is not disturbed between the cap 130 and the rudder bulb 30 and is smoothly transferred to the ship rudder 2.

22 is a rear view of a ship according to the thirteenth embodiment of the present invention, Fig. 23 is a cross-sectional view taken along line A-A' of Fig. 22, and Fig. 24 is a performance graph of the ship according to the thirteenth embodiment of the present invention.

22 and 24, the ship 1 according to the thirteenth embodiment of the present invention includes a rudder, a skeg 40, and a wedge 50. Since the rudder and the skeg 40 are the same as/similar to those described in the other embodiments, detailed descriptions are omitted.

The wedge 50 is provided adjacent to the skeg 40 and protrudes downward from the lower surface of the transom. At this time, the wedge 50 is provided on the left and right sides of the skeg 40 and fixed to the lower surface of the transom, and the height protruding downward from the lower surface of the transom increases from the front to the rear and is further away from the skeg 40. It can have a shape that decreases as it gets.

Of course, the height reduction of the wedge 50 may be made linearly and non-linearly. When the height reduction of the wedge 50 is made linearly, the wedge 50 may have a triangular shape in a front cross-section and a side cross-section. On the other hand, when the height of the wedge 50 is decreased non-linearly, the wedge 50 may have a triangular shape in which the front and side sections are partially curved.

The rear surface of the wedge 50 may be provided parallel to the rear surface of the transom. That is, the wedge 50 from the stern 3 may not protrude rearward. Also, the maximum height of the wedge 50 may be equal to or less than the maximum height of the skeg 40.

In addition, the lower end of the wedge 50 may be positioned higher than a draft (specifically, a design draft). That is, when the ship 1 sails, the wedge 50 may be provided so as not to be submerged in seawater in purified water.

When the ship 1 advances, the fluid flows backward, and the fluid rises along the lower surface of the transom. Even if the draft is located below the transom, the fluid flows along the surface of the transom. Since the fluid flows upward from the rear of the transom, it is disadvantageous in terms of the stability, thrust, and resistance of the ship (1). Can work.

On the other hand, in the present invention, by providing the wedge 50, it is possible to secure improved effects in resistance and the like. This is shown in the table below. Table 2 is the case where the draft is 11.0m, Table 3 is the case where the draft is 12.0m, Fn is the froude number, Cpx is the pressure induced resistance coefficient, Cfx is the frictional resistance coefficient, and Ct is the total resistance coefficient.

Fn 0.18 0.2 0.25 0.275 w/o
wedge Cpx: 0.50679
Cfx: 2.87079
Ct: 3.37759 Cpx: 0.5159
Cfx: 2.83451
Ct: 3.35041 Cpx: 0.60106
Cfx: 2.88433
Ct: 3.4854 Cpx: 1.1604
Cfx: 2.7656
Ct: 3.92601 w/
wedge Cpx: 0.51007
Cfx: 2.87097
Ct: 3.38104 Cpx: 0.49942
Cfx: 2.8331
Ct: 3.33253 Cpx: 0.56137
Cfx: 2.86134
Ct: 3.42271 Cpx: 1.06613
Cfx: 2.75698
Ct: 3.82312 Remark
(Ct) 100.10% 99.40% 98.20% 97.40%

Fn 0.18 0.2 0.25 0.275 w/o
wedge Cpx: 0.58461
Cfx: 2.84716
Ct: 3.43177 Cpx: 0.61461
Cfx: 2.80186
Ct: 3.41647 Cpx: 0.91976
Cfx: 2.84136
Ct: 3.76112 Cpx: 1.46453
Cfx: 2.71088
Ct: 4.17542 w/
wedge Cpx: 0.59745
Cfx: 2.84524
Ct: 3.4427 Cpx: 0.61485
Cfx: 2.83635
Ct: 3.45121 Cpx: 0.88623
Cfx: 2.83697
Ct: 3.7232 Cpx: 1.40357
Cfx: 2.7047
Ct: 4.10828 Remark
(Ct) 100.32% 101% 99% 98.40%

As can be seen from the above table and FIG. 24, when Fn increases (when the ship speed increases), the present invention provides a wedge 50, according to the transom when compared to the case without the wedge 50 As the rising flow is suppressed, the effect of increasing the resistance can be further secured.

In the above, the present invention has been described centering on the embodiments of the present invention, but this is only an example and does not limit the present invention, and those of ordinary skill in the field to which the present invention belongs will not depart from the essential technical content of the present embodiment. It will be appreciated that various combinations or modifications and applications not illustrated in the embodiments are possible in the range. Accordingly, technical contents related to modifications and applications that can be easily derived from the embodiments of the present invention should be interpreted as being included in the present invention.

That is, the present invention is not limited to the above embodiments, and both a new embodiment combining at least one of the above embodiments with a known technology and a new embodiment combining at least two of the above embodiments Include.

1: ship 2: ship rudder
3: stern 10: upper rudder
11: leading edge 111: first leading edge
112: second leading edge 12: trailing edge
20: lower rudder 21: leading edge
22: trailing edge 23: slope
30: rudder bulb 31: central axis
32: part of the schedule 33: part of the rest
34: groove 35: bulb extension
36: gap 40: skeg
41: leading edge 42: trailing edge
50: wedge 100: propeller
110: hub 120: wing
130: cap 131: cap extension

Claims (8)

In the rudder that is provided at the rear of the propeller that is coupled to the stern to generate propulsion, and controls the propulsion direction of the ship,
An upper rudder provided on the hull side;
A lower rudder provided under the upper rudder; And
Including a rudder bulb provided between the upper rudder and the lower rudder,
The rudder bulb,
When dividing the anteroposterior section into two orthogonal lines, a certain part including one part of the port or starboard from the top, the other part from the top, and one part from the bottom have a relatively small radius of curvature compared to the rest of the section. And,
Some of the above,
In the cross section in the front and rear direction, it is a part of 180 degrees or less including an upper part of one side of the port or starboard, an upper part of the other side of the port or starboard, and a lower part of one side of the port or starboard,
The rest of the above,
Ship rudder, characterized in that at least 180 degrees excluding the predetermined portion in the cross section in the front-rear direction. The method of claim 1, wherein the radius of curvature is
A ship rudder, characterized in that it is a distance between a central axis of the rudder bulb and a surface of the rudder bulb in an anteroposterior cross section. delete The method of claim 2, wherein the remaining portion,
Ship rudder, characterized in that the distance between the central axis and the surface is constant. The method of claim 2, wherein the predetermined portion,
A ship rudder, characterized in that the radius of curvature decreases and then increases from one side connected to the other part to the other side connected to the other part based on the central axis. The method of claim 1, wherein a portion abutting the remaining portion in the predetermined portion,
Ship rudder, characterized in that the radius of curvature is the same compared to the rest of the portion. The method of claim 1, wherein the rudder bulb,
Ship rudder, characterized in that positioned parallel to the rotation axis of the propeller. A ship comprising the ship rudder according to any one of claims 1, 2 and 4 to 7.

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