JP2008189197A - Stern form - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a stern form capable of reducing the hull resistance. <P>SOLUTION: The stern form has a wedge 4 having an inclined surface 5 which is fixed to a stern bottom surface 3 of a high-speed craft without any clearance and inclined backward-downwardly with respect to the stern bottom surface 3 on a longitudinal hull section, and further comprises a straightening vane 10 which is projected downward of the wedge 4 and extending in the direction of a stern 2 from a pressure-increasing part of the wedge 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a stern shape suitable for a high-speed ship such as a container ship, a ferry, a car carrier ship (PCC), and a roll-on roll-off ship (RORO).

Conventionally, when a high-speed ship navigates in the cruising speed range, the stern flow velocity is faster than the stern flow velocity, so the negative pressure at the stern increases, and the stern sinking amount is less than the bow sinking amount. growing. Therefore, from the viewpoint of hull resistance, the stern becomes enlarged and the resistance of the entire hull increases rapidly. Such a tendency is particularly remarkable in a high-speed ship in which the fluid number Fr is a predetermined number (for example, 0.30) or more.
As a solution to these problems, that is, as a stern shape that is effective in reducing hull resistance when a ship is sailing, the stern end shape is inclined slightly downward from the horizontal, called trim tab, wedge, and duck tail. It is known. (For example, see Patent Documents 1 and 2)
JP 2001-219892 A JP 2002-154475 A

However, recent ships are further required to improve performance and operational efficiency during high-speed navigation. For this reason, it is important to reduce the hull resistance during sailing, and it is desired to improve the conventional stern shape described above to further reduce the hull resistance. That is, it is desired to further improve the reduction of the hull resistance and increase the operation efficiency by further improving the conventional stern shape that improves the hull resistance by reducing the stern settlement.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a stern shape that can further reduce the hull resistance by improving the stern shape.

In order to solve the above problems, the present invention employs the following means.
The stern shape of the present invention is a stern shape provided with a water current deflecting body that is fixed to the stern bottom surface of a high-speed ship without a gap and has a lower surface inclined rearwardly downward with respect to the stern bottom surface on the longitudinal section of the hull. And a rectifying plate that protrudes downward from the water flow deflector and extends in a stern direction from a pressure increasing portion of the water flow deflector.

  According to such a stern shape, since the rectifying plate protrudes downward from the water flow deflector and extends in the stern direction from the pressure rising portion of the water flow deflector, the flow around the water flow deflector is rectified. Further, it is possible to prevent the formation of a flow from the water flow deflector toward the outside.

  In the above invention, it is preferable that a pair of the rectifying plates is provided in contact with both side ends of the water flow deflector, so that the rectifying plates provided at both ends of the water flow deflector are arranged outside the water flow deflector. It is possible to rectify while efficiently preventing the formation of a flow toward.

In the above invention, it is preferable that the rectifying plate is provided in a pair or a plurality of pairs at an intermediate portion of the water flow deflector, whereby the height of the water flow deflector is particularly high at the center (the hull center line). The rectification can be performed efficiently when the left and right are lowered. Further, when a plurality of pairs of rectifying plates are provided, the rectifying plate on the hull center line side efficiently rectifies, and the outer (ship side) rectifying plate prevents the formation of a flow toward the outside. Each pair of rectifying plates is preferably arranged symmetrically on the left and right of the hull center line.
In this case, the length of the rectifying plate is preferably different for each of a plurality of pairs according to the height of the water flow deflector, thereby minimizing the resistance of the rectifying plate itself.

  In the above invention, the flow straightening plate is preferably provided in a square shape with the front side of the hull open in a plan view, so that the flow flows near the central portion (hull center line) of the water flow deflector. They can be rectified as they are collected.

  In the above invention, it is preferable that the current plate is provided in the shape of a letter C that is open downward when viewed from the front-rear direction of the hull. Rectification can be performed.

  According to the present invention described above, by providing the rectifying plate that protrudes downward from the water flow deflector and extends in the stern direction from the pressure rising portion of the water flow deflector, the rectifying plate causes the flow around the water flow deflector to flow. It rectifies and further improves the pressure rise effect on the hull surface by the water flow deflector. Moreover, since this baffle plate prevents formation of the flow which goes outside from a water flow deflecting body, it can prevent the increase in resistance by the wave formation by this flow and wave collapse. Therefore, according to the stern shape of the present invention, it is possible to further reduce the hull resistance particularly during high-speed navigation, so that a remarkable effect of improving the marine vessel running performance and operational efficiency can be obtained.

Hereinafter, an embodiment of a stern shape according to the present invention will be described with reference to the drawings.
2, (a) is a side view showing a high-speed ship equipped with a water flow deflector, (b) is an enlarged view of the main part of the stern bottom part, and (c) is a rear view of the stern bottom part (viewed from the rear of the hull). Figure).
On the stern 2 of the hull 1, a wedge 4 as a water flow deflector is attached to the stern bottom 3, which is the bottom portion of the stern 2, so as to be symmetrical about the hull center line CL. The wedge 4 is a portion where an inclined surface (lower surface) 5 is inclined with respect to the stern bottom surface 3 so as to have a rearward downward angle θ. Alternatively, it may be formed integrally with the stern bottom 3 side.

The rough shape of the wedge 4 described above is a prismatic shape in which the side surface shape is a triangular shape and the wedge rear surface 6 is a horizontally long rectangle. And in the state which attached this wedge 4 to the stern bottom 3, the planar shape becomes a substantially circular arc shape with the front end side convex forward. Further, the wedge 4 is arranged so that the wedge rear surface 6 is flush with the stern rear surface 7 which is the rear end surface of the stern 2. For this reason, the wedge 4 does not protrude rearward with respect to the stern 2, and thus the total length of the hull 1 is not increased. However, if the total length of the hull is not taken into consideration, the wedge 4 may be disposed so as to protrude from the stern rear surface 7.
In addition, the wedge 4 of such a water flow deflector is also called a trim tab or a duck tail. In the figure, reference numeral 7 denotes a stern rear surface of the hull 1, 8 a bow, and 9 a propeller.

In addition, the inclined surface 5 inclined downward and downward is defined as a lower surface that gradually descends downward toward the rear of the hull 1 when the traveling direction at the time of forward movement of the ship is the front and the opposite direction to the front is the rear. I mean. In the following description, the horizontal direction perpendicular to the front-rear direction is defined as the hull width direction, and the left and right in the hull width direction are defined with reference to the traveling direction when the ship advances.
Here, the high-speed ship means all ships whose resistance reduced by the wedge 4 can be larger than the resistance caused by the wedge 4 when the wedge (water flow deflector) 4 is attached to the hull 1. For example, a ship having a fluid number of 0.35 or more is applicable. However, even if the number of fluids is smaller than 0.35, the ship that can increase the resistance reduced by the wedge 4 is included regardless of the scale of the ship.

  In this way, in the hull 1 of a high-speed ship, a water flow is generated along the hull 1 when navigating the ship by attaching the wedge 4 that forms the inclined surface 5 with respect to the stern bottom 3. A water flow that flows backward along the inclined surface 5 of the wedge 4 is generated. Since this water flow is deflected downward along the inclined surface 5, the stern 2 is pushed upward by this deflected water flow, and the amount of settlement on the stern side can be reduced. Therefore, the resistance caused by the stern 2 sinking can be reduced, and the stability can be enhanced by leveling the hull 1. Such an action of the wedge 4 is substantially equal in the left-right direction of the hull center line CL because the wedge 4 is provided symmetrically.

In contrast to the stern shape described above, in the present invention, for example, in the first embodiment shown in FIG. A rectifying plate 10 extending in the direction is provided. In this case, the pressure increasing portion means a position where a pressure that pushes up the stern 2 in front of the wedge 4 is generated when the water flow along the stern bottom 3 is deflected downward along the inclined surface 5. ing.
The range of the pressure increasing portion that determines the mounting range of the current plate 10 is, for example, about 60 times the length of the wedge 4 with reference to the height of the wedge 4 or the length of the wedge 4 as the rear end. It is about 10 times based on the direction length.

In the embodiment shown in FIG. 1, a pair of rectifying plates 10 is provided in contact with the left and right ends of the wedge 4. The rectifying plate 10 is a plate-like member attached downward from the surface of the stern bottom 3 or toward the outside of the hull 1 substantially perpendicularly from the surface of the stern bottom 3. The front portion of the current plate 10 is attached so that the amount of protrusion from the surface of the stern bottom 3 becomes small or the same as the surface of the stern bottom 3 so as not to become hull resistance. Yes. Further, at the stern end 7 side of the rectifying plate 10, the rectifying plate 10 has a height substantially the same as the wedge 4 so as not to become a hull resistance, or protrudes from the wedge 4 so as to be downward from the surface of the stern bottom 3. It is attached toward. That is, the current plate 10 is fixed by welding or the like with the plate thickness surface abutting against the stern bottom 3.
With such a configuration, since the rectifying plate 10 is attached in contact with the left and right side end portions of the wedge 4, the flow of water flowing backward along the wedge 4 is restricted by the rectifying plate 10. The That is, when the water flow toward the rear along the wedge 4 is rectified by the regulation of the rectifying plate 10, there is almost no outward flow and the turbulence generated in the streamline is small. As a result, the effect of increasing the pressure on the hull surface by the wedge 4 is improved, and wave formation and wave collapse due to the flow toward the outside of the wedge 4 are also suppressed. Therefore, by combining the current plate 10 with the wedge 4, the hull resistance is reduced by improving the pressure rise effect, and further, the increase in resistance due to the suppression of wave formation and wave collapse is also prevented.

Next, a stern-shaped second embodiment according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part similar to embodiment mentioned above, and the detailed description is abbreviate | omitted.
In this embodiment, when the cross-sectional shape of the wedge 4A is a curved surface convex downward from the inclined surface 5A, and the wedge height is high at the center of the hull 1, the pair of left and right rectifying plates 10A are intermediate between the wedges 4A. The structure provided in the part is shown. That is, the pair of left and right rectifying plates 10A is provided not at both ends of the wedge 4A but at a midway position that is symmetrical with respect to the hull center line CL. The rectifying plate 10A in this case is also attached in consideration of the hull resistance, as with the rectifying plate 10 described above.
In addition, since the wedge 4A in this case is a curved surface having a high central portion, the planar shape of the front end portion is an arcuate curve when attached to the stern bottom 3.

Even with such a configuration, the effect of increasing the pressure on the hull surface by the wedge 4A can be improved. In particular, the rectifying plate 10A of the present embodiment is suitable when the wedge height is high in the central portion and low on both the left and right sides, and can further enhance the rectifying effect in the vicinity of the central portion where the pressure increasing effect is high.
Note that the rectifying plate 10A of the present embodiment is applicable even when the wedge height is uniform in the hull width direction, and can be combined with the rectifying plates 10 attached to both ends of the wedge.

  In the above-described embodiment, a pair of right and left rectifying plates 10A is provided. However, for example, as in the first modification shown in FIG. The rectifying effect can be further increased by providing two pairs of rectifying plates 10A. The rectifying plate 10A in this case is also attached in consideration of the hull resistance, as with the rectifying plate 10 described above. In such a configuration, the rectifying plate 10A near the center further improves the rectifying effect near the center where the effect of increasing pressure is high, and the rectifying plates 10A on both the left and right sides suppress the flow toward the outside, thereby generating waves and waves. An increase in resistance due to collapse can be prevented.

Moreover, in embodiment mentioned above, you may employ | adopt the structure which attached the rectifying plates 10A and 10B from which length differs for every pair like the 2nd modification shown, for example in FIG. In this case, the current plate 10A, 10B is adjusted to an optimum length according to the height of the wedge at each current plate mounting position. That is, the length of the rectifying plate 10A located at the central portion where the wedge height is high is set long, and the length of the rectifying plates 10B on the left and right sides where the wedge height is low is set short. Note that the rectifying plates 10A and 10B in this case are also attached in consideration of the hull resistance, similarly to the rectifying plate 10 described above.
With such a configuration, the effect of increasing the pressure on the hull surface by the wedge 4A can be improved as in the above-described embodiment. And by changing the length of the rectifying plates 10A and 10B according to the magnitude of the pressure rise effect due to rectification, the resistance caused by the rectifying plates 10A and 10B itself is minimized, and the resistance reduction effect as a whole stern shape is improved. Can be made. That is, by suppressing the resistance of the rectifying plate itself, which is a projection, to a minimum, it is possible to reduce the amount of offset reduction of the resistance reduction effect caused by attaching the rectifying plate.

Moreover, in embodiment mentioned above, it is good also as a structure which attached 10 C of rectification | straightening plates which opened the hull front side in the C shape by planar view like the 3rd modification shown, for example in FIG. That is, the rectifying plate 10C is attached in a square shape in which each pair of bilateral symmetry with respect to the hull center line CL is widened in the hull width direction and narrowed rearward. In this case, the inclination angle of the rectifying plate 10C with respect to the hull center line CL is preferably set to a range of about 0 ° to 10 °, for example, so as not to cross the flow and become resistance. Note that the rectifying plate 10C in this case is also mounted in consideration of the hull resistance, similarly to the rectifying plate 10 described above.
With such a configuration, the effect of increasing the pressure on the hull surface by the wedge 4A can be improved as in the above-described embodiment. And since the inclination angle is provided in the rectifying plate 10C so as to rectify the flow toward the center of the high wedge 4A, the effect of increasing the pressure on the hull surface can be further improved.

Moreover, in embodiment mentioned above, the structure which attached 10D of rectification | straightening plates provided in the C-shape which opened below seeing from the hull front-back direction like a 4th modification shown, for example in FIG. 7 is employ | adopted. May be. That is, the rectifying plate 10D is attached in the shape of a letter C in which each pair that is bilaterally symmetric with respect to the hull center line CL is widened downward and narrowed upward on the stern bottom 3 side. In this case, the inclination angle of the rectifying plate 10D with respect to the vertical line is preferably set to a range of about 0 ° to 10 °, for example. In addition, consideration is given to the current plate 10D in this case so as not to cause hull resistance, similar to the current plate 10 described above.
With such a configuration, the effect of increasing the pressure on the hull surface by the wedge 4A can be improved as in the above-described embodiment. In particular, when the ship bottom of the hull 1 is not horizontal, a straightening plate 10D perpendicular to the bottom of the ship can be attached, so that smooth rectification is possible, and as a result, the effect of increasing the pressure on the hull surface is further improved. Can do.

  The rectifying plates 10A to 10D of the respective modifications described above can be appropriately combined and employed in accordance with the hull 1 or the wedge 4A. That is, various combinations are possible, such as opening the rectifying plate 10B shown in FIG. 5 in a square shape in plan view, or opening it in a square shape when viewed from the front and rear of the hull.

As described above, according to the stern shape of the present invention, the rectifying plates 10, 10 </ b> A to 10 </ b> D that protrude downward from the wedges 4, 4 </ b> A of the water flow deflector and extend in the stern direction from the pressure rising portion of the stern bottom surface 3. The rectifying plates 10, 10A to 10D rectify the flow around the wedge and further improve the effect of increasing the pressure on the hull surface by the wedges 4 and 4A.
Further, since the rectifying plates 10 and 10A to 10D perform rectification while preventing the outward flow from the wedges 4 and 4A, the increase in resistance due to wave generation and wave collapse due to the outward flow is prevented. be able to.

Therefore, the stern shape of the present invention can further reduce the hull resistance particularly during high-speed navigation, so that it is possible to improve the navigation performance and operational efficiency of the ship.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.

BRIEF DESCRIPTION OF THE DRAWINGS The 1st Embodiment of the stern shape which concerns on this invention is shown, (a) is a principal part enlarged view of a stern bottom part, (b) is a rear view which shows a stern bottom part. The high-speed ship provided with the water flow deflector (wedge) is shown, (a) is a side view of the high-speed ship, (b) is a main part enlarged view showing the stern bottom part of (a), (c) is (a) It is a rear view which shows the stern bottom part of (). The 2nd Embodiment of the stern shape which concerns on this invention is shown, (a) is a principal part enlarged view of a stern bottom part, (b) is AA sectional drawing of (a), (c) is (a FIG. It is a bottom view which shows the 1st modification of 2nd Embodiment shown in FIG. It is a bottom view which shows the 2nd modification of 2nd Embodiment shown in FIG. It is a bottom view which shows the 3rd modification of 2nd Embodiment shown in FIG. 10 shows a fourth modification of the second embodiment shown in FIG. 3, (a) is a bottom view, and (b) is a BB cross-sectional view of (a).

Explanation of symbols

1 Hull 2 Stern 3 Stern bottom 4,4A Wedge (water flow deflector)
5,5A Inclined surface (lower surface)
10, 10A-D Rectifier plate

Claims (6)

A stern shape having a water flow deflector that is fixed to the stern bottom surface of a high-speed ship without a gap and has a bottom surface that is inclined rearward and downward with respect to the stern bottom surface on the hull longitudinal section,
A stern shape characterized by comprising a rectifying plate that protrudes downward from the water flow deflector and extends in a stern direction from a pressure rise portion of the water flow deflector.   The stern shape according to claim 1 or 2, wherein a pair of said baffle plates are provided in contact with both side ends of said water flow deflector.   2. The stern shape according to claim 1, wherein a pair or a plurality of pairs of the rectifying plates are provided in an intermediate portion of the water flow deflector.   4. The stern shape according to claim 3, wherein the length of the rectifying plate is different for each of a plurality of pairs according to a height of the water flow deflector.   The stern shape according to any one of claims 2 to 4, wherein the rectifying plate is provided in a square shape with a front side of the hull opened in a plan view.   6. The stern shape according to claim 2, wherein the baffle plate is provided in a cross-sectional shape that opens downward when viewed from the front-rear direction of the hull.

Images