JP4024793B2 - Pitching reduction device for ships - Google Patents

Description

  The present invention relates to a ship pitching reduction device that reduces pitching in a sailing direction of a large ship having a stern with a buttocks flow surface that is inclined almost horizontally.

  There are two types of swaying of a vessel that is sailing: pitching, which is pitching in the sailing direction, and rolling, which is lateral rolling with respect to the sailing direction. Pitching and rolling hull motion is based on the period of waves incident upon the hull force acting on the hull, and the hull movement is maximized when the natural motion period of the hull synchronizes with the incident wave period. In general, the hull motion at the tuning point increases as the vessel speed increases, and therefore, it is considered that the hull motion at the time of tuning is larger in a container ship or a car carrier than in a bulky ship such as a tanker.

  Here, the pitching will be outlined based on FIG. FIG. 7 is a diagram in which a vessel that is sailing in a wave is pitching. A downward gravity acting on the center of gravity G and an upward buoyancy acting on the buoyancy B are acting on the ship 201, and the center line CL is the center line of the ship connecting the centroid G and the buoyancy B in the normal water ( FIG.7 (b) is the figure which showed the same inclination as the ship 201 at the time of a flat water.) When the ship 201 navigating the waves 202 causes pitching, the bow moves up and the stern goes down (FIG. 7 (a)), and then the bow goes down and the stern goes up (FIG. 7 (c)). repeat. When the bow is raised and the stern is lowered, the buoyancy B moves to the stern side (FIG. 7A), but the intersection of the perpendicular line PL passing through the buoyancy B and the center line CL is called a vertical metacenter M. Similarly, as shown in FIG. 7C, when the bow is lowered and the stern is raised, the intersection of the perpendicular line PL passing through the buoyancy B and the center line CL is referred to as a vertical metacenter M, and FIG. The vertical metacenter M in 7 (c) is the same point. That is, the pitching is oscillated at a predetermined cycle by the wave energy around the vertical metacenter M.

  On the other hand, in container ships and car carriers, the buttock flow hull form with a wide waterline surface is used to maximize the capacity of the vessel and to increase the lateral metacenter due to stability. Adopted.

  When a vessel having a stern with such a strong buttocks flow causes severe pitching, a case occurs where the buttocks flow surface is slammed against the water surface and the stern member is damaged. Furthermore, the container ship and the car carrier ship have a propeller diameter with respect to flooding larger than that of a tanker or other large-sized ship, and when the ship pitches, propeller racing is likely to occur where the propeller is exposed from the water surface.

  The stern with a strong buttocks flow here is a stern shape in which the stern is overhanging on the full flooded line in the side view of the stern, and the overhanging stern part of the stern is in the horizontal direction. Say.

  As a technique for reducing or attenuating the pitching of the ship, there is a technique disclosed in Japanese Patent Application Laid-Open No. 2004-90882. An outline of this technique will be described with reference to FIG. FIG. 6 is an example of the technique disclosed in Japanese Patent Application Laid-Open No. 2004-90882, and is a side view of a ship adopting a ship anti-shake device using only a ballast tank.

  The technique disclosed in Japanese Patent Application Laid-Open No. 2004-90882 aims to provide a ship vibration reduction device that can effectively suppress the pitching of the ship, and the means for solving the problem is as follows.

  The ship 101 is provided with ballast tanks 104 and 105 at the bow 102 and the stern 103, respectively. The ballast tanks 104 and 105 are J-shaped. One ballast tank 104 is provided with bowl-shaped water storage chambers 106 and 107, and a fluid 109 is stored in the water storage chambers 106 and 107. Of the water storage chambers 106 and 107, the short water storage chamber 107 is hermetically sealed and provided with an air chamber 110, and the water level of the water storage chambers 106 and 107 is higher on the tall water storage chamber 106 side. The other tank 105 is provided with water storage chambers 111, 112, and the water storage chamber 112 with a short height among the water storage chambers 111, 112 is provided with an air chamber 114, and each water surface height of the water storage chambers 111, 112 is The tall reservoir 111 side is raised. The air chambers 110 and 114 serve as air springs so that the natural frequency of the air spring matches the natural frequency of pitching of the ship 101 and the flow (phase) of the fluid 109 is in the opposite direction. Set.

With such a configuration, the vibration reduction device for the ship is provided with water tanks at the bow and stern of the ship, and at least two or more water storage chambers are provided in the water tank front-rear direction, and the water storage chambers in each water tank are provided. To allow alternating fluid flow between the reservoirs, causing the alternating flow of fluid to flow in accordance with the pitching cycle of the vessel, and the flow direction of the fluid to flow at the bow and stern. The center of gravity of the fluid in the aquarium was reversed up and down, and the couple generated by moving the center of gravity of the fluid was in the opposite phase to the direction of the ship's shaking. It is possible to reduce the shaking of the ship.
JP 2004-90882 A

  However, the ship anti-vibration device disclosed in Japanese Patent Application Laid-Open No. 2004-90882 has a complicated structure, requires a predetermined ship space, and is considered to be expensive.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a ship pitching mitigation device that has a simple configuration and is excellent in economy without sacrificing the volume of a ship.

In order to solve the above problems, the pitching reducing apparatus of a ship according to the claims 1 from bow to Batokkufuro surface of left and right is formed on top of the stern rudder and propeller container ship or automotive transport ship having Batokkufuro stern A plurality of rectifying plates inserted and fixed so as to be substantially parallel to the stern direction, and a damper plate having a substantially rectangular or trapezoidal shape in plan view in which a plurality of through holes are drilled in the plurality of rectifying plates are predetermined. The space formed by the buttocks flow surface and the damper plate in the gap and above the full water draft is the bow-side opening and stern-side opening with the bow-side end and stern-side end open. A portion is formed .
A pitching reduction device according to claim 2 of the present application is the boat pitching reduction device according to claim 1, wherein the edge of the damper plate on the center axis side of the boat is bent obliquely upward. Features.
A pitching reduction device according to claim 3 of the present invention is the boat pitching reduction device according to claim 1 or 2 , wherein the through holes are circular and / or substantially circular and are adjacent to each other. A hole is formed between the current plates.

  The ship pitching reduction device according to claim 1 of the present application has the following effects because a damper plate having a large number of through holes is attached to the buttocks flow surface with a predetermined gap.

(1) Due to the pitching of the ship, when the water hits the damper plate and the water passes through many through holes drilled in the damper plate, or when the damper plate floats in the water, the water is drilled in the damper plate. When passing through a large number of through-holes, vortices are generated around the through-holes, and the resistance of the vortices reduces the force in the direction of motion and reduces the pitching of the ship. This mechanism will be described later. Furthermore, propeller racing is prevented by reducing the pitching of the ship.

(2) The apparatus has a simple structure, and no special equipment for operating the apparatus is required, which is economical and easy to maintain.

(3) The apparatus is an outboard apparatus to be attached to the outside of the ship, and can be attached to an existing ship as well as a new ship, and is excellent in versatility.

Moreover, since the pitching reduction device for a ship according to claim 1 of the present application is provided with both sides of the damper plate divided into two by sandwiching the propeller, the damper plate has a substantially flat surface shape, such as a bending process. Complex processing technology is not required.

And since the pitching reduction apparatus of the ship which concerns on this-application claim 1 attaches a damper board to the upper part rather than the full load floodline at the time of a flat water,
(1) In a ship that is traveling in flat water without causing pitching, the damper plate does not hinder the propulsion power of the ship.
(2) In addition, marine organisms such as shellfish are less likely to adhere to the damper plate, the performance can be prevented from deteriorating, and the running cost is low.

Moreover, since the pitching reduction apparatus of the ship which concerns on this-application Claim 1 has several baffle plates inserted and fixed in parallel with the front-back direction of a ship between a buttocks flow surface and a damper board,
(1) The water that has entered between the buttocks flow surface and the damper plate is smoothly discharged from the bow side and the stern side along the plurality of rectifying plates, and the water that intrudes between the buttocks flow surface and the damper plate one after another. It won't get in the way. Therefore, the generation of vortices due to the invading water is surely generated, and the performance of the pitching reduction device for the ship is not deteriorated.
(2) The rectifying plate is installed from the bow side end of the damper plate to the stern side end. This rectifying plate maintains the distance between the damper plate and the buttocks flow surface, and the damper plate supports from the buttocks flow surface. Therefore, it is possible to increase the rigidity of the damper plate and withstand the strong impact of the water surface hitting the damper plate.

Further, in the ship pitching reduction device according to claim 2 of the present invention, since the edge of the damper plate on the central axis side of the ship is bent obliquely upward, the area of the buttocks flow surface is substantially reduced, and the damper plate The impact on the surface of the water hits.

And since the pitching reduction apparatus of the ship which concerns on this-application Claim 3 makes the shape of a through-hole circular and / or substantially circular, generation | occurrence | production of the vortex by the water which passes through a through-hole is performed smoothly and reliably.

  Example 1 and Example 2 according to the best mode for carrying out the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram of a ship pitching reduction device according to the first embodiment. FIG. 1A is a side view of a stern portion of the ship to which the boat pitching reduction device according to the first embodiment is attached. FIG. 1C is a stern front view of the stern part of the ship to which the ship pitching reduction device according to the first embodiment is attached, and FIG. 1C is a stern front view of the ship to which the boat pitching reduction device according to the first embodiment is attached. . And FIG. 2 is the one whole figure divided into two of the pitching reduction apparatus of the ship which concerns on Example 1. FIG. FIG. 3 is a schematic diagram of a ship pitching reduction device according to the second embodiment. FIG. 3A is a side view of the stern portion of the ship to which the boat pitching reduction device according to the second embodiment is attached. FIG. 3B is a stern front view of the stern part of the ship to which the ship pitching reduction device according to the second embodiment is attached. FIG. 3C is a front view of the stern part of the ship to which the ship pitching reduction device according to the second embodiment is attached. It is. And FIG. 4 is the one whole figure divided into two of the pitching reduction apparatus of the ship which concerns on Example 2. FIG. Furthermore, FIG. 5 is an explanatory view of the consumption mechanism of wave energy by the damper plate.

  First, the wave energy consumption mechanism by the damper plate will be described with reference to FIG. In FIG. 5, reference numeral 11 is a damper plate, reference numeral 12 is a through hole, reference numeral 20 is a ship, reference numeral 22 is a buttocks flow surface, reference numeral 31 is a water flow, and reference numeral 32 is a vortex.

  When the water flow 31, which is seawater, collides with the damper plate 11, a part of the water flow 31 passes through the through hole 12 provided in the damper plate 11. And the water flow 31 which passed through the through-hole 12 becomes a vortex when passing through the through-hole 12, and the energy of this water flow 31 is consumed. In other words, the damper plate 11 acts as a damper for pitching, and the pitching fluctuation width is reduced.

Although not shown in FIG. 5, even when the damper plate 11 submerged in the water floats on the water as the stern rises, a part of the downward water flow penetrates the damper plate 11. Go through. Also in this case, the downward water flow generates a vortex, and the generation of this vortex consumes the energy of the water flow, the damper plate 11 acts, and the upward force is reduced.
Therefore, the damper plate 11 consumes wave energy and reduces pitching due to the vortex-forming resistance of the through-holes 12 both when submerged in the water and ascends from the water.

Next, a boat pitching reduction apparatus according to a first embodiment will be described with reference to FIGS. 1 and 2.
1 and 2, reference numeral 1 denotes a ship pitching reduction device according to the first embodiment, reference numeral 11 denotes a damper plate, reference numeral 12 denotes a through hole, reference numeral 13 denotes a rectifying plate, reference numeral 14 denotes a bow side opening, and reference numeral 15 denotes A stern side opening part, the code | symbol 20 is a ship, the code | symbol 21 is a stern, the code | symbol 22 is a buttocks flow surface, the code | symbol 23 is a rudder, and the code | symbol 24 is a propeller.
In FIG. W. L is a load water line, and CL is a ship center line. The same applies to FIG.

  As shown in FIG. 2, the ship pitching reduction device 1 includes a damper plate 11 having a plurality of through holes 12 and a substantially rectangular damper plate 11 in plan view and a plurality of rectifying plates 13. 23 and the buttocks flow surface 22 of the starboard and port side formed in the upper part of the propeller 24. The rectifying plates 13, 13,... Are suspended from the damper plate 11 so as to be substantially parallel to the direction from the bow of the ship 20 to the stern, and the damper plate 11 includes the rectifying plates 13, 13,. It is attached to the buttocks flow surface 22 of both right and left sides. The space formed by the buttocks flow surface 22 and the damper plate 11 is in a state in which the bow side end and the stern side end are opened, and the bow side opening part 14 and the stern side opening part 15 are formed.

  In addition, the ship pitching reduction device 1 is a fully loaded floodline L.P. W. It is attached to the buttocks flow surface 22 so that it may be located above L. In addition, the through holes 12, 12,... Are circular, and are drilled between the adjacent rectifying plates 13, 13. In this embodiment, the diameter of the through hole 12 is about 150 mm, and the height of the rectifying plate 13, that is, the gap between the buttocks flow surface 22 and the damper plate 11 is about 300 mm.

Here, the effect | action of the pitching reduction apparatus 1 of a ship is demonstrated.
When the sailing ship is pitching and its stern part enters the sea surface, the ship pitching mitigation device 1 collides with the sea surface. Then, due to the collision of the sea surface, a part of the sea water enters the space formed by the buttocks flow surface 22 and the damper plate 11 through the through holes 12, 12,. A vortex is generated on the side of the buttocks flow surface 22 of the plate 11, and the energy that collides with the sea surface is consumed by the generation of this vortex. As a result, the pressure on the sea surface acting on the buttocks flow surface 22 is reduced and the damper plate 11 is pitched. Acting as a damper against the pitching pitch decreases.

  Seawater that has entered the space formed by the buttocks flow surface 22 and the damper plate 11 extends along the rectifying plate 13 to the bow side opening portion 14 and the stern side opening formed at the bow side end portion and the stern side end portion of the damper plate 11. It is quickly discharged from the section 15. Therefore, it does not obstruct the seawater entering the space formed by the buttocks flow surface 22 and the damper plate 11 one after another, and does not reduce the function of the vessel pitching reduction device 1.

  The pitching mitigation device 1 for a ship once submerged in the sea rises from the sea. In this case as well, seawater replenished from the bow-side opening part 14 and the stern-side opening part 15 passes through the through-hole 12. , 12,... At that time, as described above, a vortex is generated on the outer side (seawater side) of the damper plate 11, and the generation of this vortex suppresses the force that causes the stern to rise, thereby reducing the pitching fluctuation width. Further, when the pitching reduction device 1 is separated from the sea surface by pitching, the seawater in the space formed by the buttocks flow surface 22 and the damper plate 11 is not only the bow side opening portion 14 and the stern side opening portion 15 but also the through hole 12. , 12,... Are quickly discharged and prepared for the next collision of the vessel pitching mitigation device 1 with the sea surface.

Next, a boat pitching reduction apparatus according to a second embodiment will be described with reference to FIGS. 3 and 4.
3 and 4, reference numeral 2 denotes a ship pitching reduction device according to the second embodiment, reference numeral 11 denotes a damper plate, reference numeral 12 denotes a through hole, reference numeral 13 denotes a rectifying plate, reference numeral 14 denotes a bow side opening, and reference numeral 15 denotes A stern side opening part, the code | symbol 16 is a bending part, the code | symbol 20 is a ship, the code | symbol 21 is a stern, the code | symbol 22 is a buttocks flow surface, the code | symbol 23 is a rudder, and the code | symbol 24 is a propeller.

  The difference between the second embodiment and the first embodiment is the shape of the damper plate 11, and the configuration and operation of other technical elements are exactly the same as those of the first embodiment. Therefore, in the second embodiment, the shape and operation of the damper plate 11 different from the first embodiment will be mainly described, and the configuration of other technical elements will be denoted by the same reference numerals as those in the first embodiment and the description thereof will be omitted. In addition, the description of the operation is also omitted.

  The damper plate 11 according to the second embodiment is the same as the first embodiment in that a large number of through holes 12 are perforated. However, in the second embodiment, the edge of the damper plate 11 on the center axis side of the ship is bent toward the buttocks flow surface 22 side to form the bent portion 16, and the width of the bow side opening portion 14 is the width of the stern side opening portion. The damper plate 11 is configured to be narrower than the width, and the damper plate 11 is substantially trapezoidal in plan view.

  Due to the difference in configuration, the area of the damper plate 11 is smaller than the area of the damper plate 11 in the first embodiment, and the impact received when the pitching mitigation device 2 of the ship collides with the sea surface due to pitching reduces the pitching of the ship. It is gentler than the impact received by the device 1. Therefore, the ship pitching reduction device 2 can reduce the plate thickness of the members constituting the ship by about one step and is more economical than the boat pitching reduction device 1.

FIG. 1 is a schematic diagram of a ship pitching reduction device according to the first embodiment. FIG. 1A is a side view of a stern portion of the ship to which the boat pitching reduction device according to the first embodiment is attached. FIG. 1C is a stern front view of the stern part of the ship to which the ship pitching reduction device according to the first embodiment is attached, and FIG. 1C is a stern front view of the ship to which the boat pitching reduction device according to the first embodiment is attached. . FIG. 2 is an overall view of one of the two divided pitting mitigation devices for a ship according to the first embodiment. FIG. 3 is a schematic diagram of a ship pitching reduction device according to the second embodiment. FIG. 3A is a side view of a stern portion of the ship to which the boat pitching reduction device according to the second embodiment is attached. ) Is a stern front view of the stern part of the ship to which the pitching reduction device for a ship according to the second embodiment is attached, and FIG. 3C is a front view of the stern part of the ship to which the pitching reduction device for a ship according to the second embodiment is attached. . FIG. 4 is an overall view of one of the two divided pitting mitigation devices for a ship according to the second embodiment. FIG. 5 is an explanatory diagram of the mechanism of consumption of wave energy by the damper plate. FIG. 6 is an example of the technique disclosed in Japanese Patent Application Laid-Open No. 2004-90882, and is a side view of a ship adopting a ship anti-shake device using only a ballast tank. FIG. 7 is a diagram in which a vessel sailing during a wave is causing pitching.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pitching reduction apparatus of the ship which concerns on Example 1 2 Pitch reduction apparatus of the ship which concerns on Example 2 11 Damper plate 12 Through-hole 13 Current plate 14 Bow side opening part 15 Stern side opening part 16 Bending part 20 Ship 22 Buttoc flow surface

Claims (3)

A plurality of rectifying plates that are mediated挿固wear to be substantially parallel to the direction of from the bow to Batokkufuro surface of left and right is formed on top of the stern rudder and propeller container ship or automotive transport ship aft having Batokkufuro stern A plurality of through-holes are drilled in the plurality of rectifying plates, and the damper plate having a substantially rectangular or trapezoidal shape in plan view is provided at a predetermined gap and above the full water draft, and the buttocks flow surface and the damper plate The space formed by is formed with a bow side opening portion and a stern side opening portion in a state where the bow side end portion and the stern side end portion are opened . The ship pitching mitigation device according to claim 1, wherein the edge of the damper plate on the center axis side of the ship is bent obliquely upward. The said pitching hole is circular and / or substantially circular, Comprising: The said pitching reduction apparatus of the ship of Claim 1 or Claim 2 drilled between the said baffle plates adjacent to each other.

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