CSBC

Abstract

To provide a barge that can lower the center of gravity of the hull. [Solution] The hull 1 has a plurality of recesses 11 that are recessed upward from the bottom 1b and extend in the width direction D2 and the longitudinal direction D1. The hull 1 also has thrusters 4 provided on the upper part 11a of each recess 11. This reduces the amount that the thrusters 4 protrude from the bottom 1b, or makes it possible to have a structure in which the thrusters 4 do not protrude from the bottom 1b. In addition, the position of the bottom 1b of the hull 1 is lower than that of a basic hull 201 (see the right side of Figure 5) of the same displacement volume that does not have a plurality of recesses 11.Therefore, the hull 1 can be structured in such a way that the parts of the hull 1 other than the recesses 11 are generally lowered.As a result, the center of gravity of the hull 1 can be lowered.

Description

Technical Field

[0001] The present invention relates to a support vessel.

Background Art

[0002] When installing ocean structures such as offshore wind power, for example, a support vessel equipped with a crane is used (for example, Patent Document 1). Support vessels equipped with a crane include a SEP vessel / jack-up support vessel that uses legs to raise a platform above the sea surface for work, and a method that uses a DPS (Dynamic Positioning System) to fix the position of the support vessel for work. Among the above methods, the SEP vessel / jack-up support vessel method that uses legs to raise a platform above the sea surface for work has a depth limit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the waters off Japan are deep, in the future, when offshore wind power generation becomes widespread and it is necessary to work even in deep waters, it is necessary to use a working method using DPS. On the other hand, the installation location of offshore wind power generation facilities is in a sea area with strong winds, and from the perspective of work efficiency, high weather resistance and stability are required for the support vessel for work. However, due to port conditions and the like, there is a limit to the size of the support vessel, so the main dimensions cannot be easily increased to improve stability. Therefore, it has been required to ensure stability by lowering the center of gravity while suppressing an increase in the main dimensions of the hull.

[0005] This invention was made to solve these problems and aims to provide a barge that can lower the center of gravity of the hull. [Means for solving the problem]

[0006] The barge according to the present invention comprises a hull having a plurality of recesses that curve upward from the bottom of the hull, and thrusters provided above each recess for maintaining position during operation. Compared to a basic hull of the same displacement volume that does not have a plurality of recesses, the position of the bottom of the hull relative to the water surface is lower.

[0007] In the barge according to the present invention, the hull has a plurality of recesses that are indented upward from the bottom of the hull. The hull also has thrusters provided above each of the recesses. This reduces the amount that the thrusters protrude from the bottom of the hull, or allows for a structure in which the thrusters do not protrude from the bottom of the hull at all. Furthermore, compared to a basic hull of the same displacement volume that does not have a plurality of recesses, the position of the bottom of the hull relative to the water surface is lower. Therefore, the structure can be such that the parts of the hull other than the recesses are generally lowered downwards. As a result, the center of gravity of the hull can be lowered.

[0008] The hull may have recesses extending in the width direction and recesses extending in the longitudinal direction. In this case, the water flow generated by the thruster can pass through the recesses extending in the width direction, avoiding interference with the hull. Also, the water flow generated by the thruster can pass through the recesses extending in the longitudinal direction, avoiding interference with the hull.

[0009] Multiple recesses may be provided along the outer edge of the hull. In this case, the water flow generated by the thruster passes through the recesses, making it easier to avoid interference with the hull.

[0010] The hull may be equipped with a crane, and the thrusters may generate thrust in the opposite direction to the external force acting on the crane during operation. In this case, even if an external force acts on the hull, the thrust from the thrusters can maintain its position.

[0011] The thrusters may be controlled so that the moment of the external force balances the moment of thrust from each thruster. This allows the thrusters to generate thrust that maintains the ship's position even when external forces act on the ship.

[0012] The thruster may be controlled to counteract the moment of external forces that vary based on the crane angle. This allows the thruster to generate thrust that maintains the ship's position even when external forces that vary based on the crane angle are acting on it. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a barge that can lower the center of gravity of the hull. [Brief explanation of the drawing]

[0014] [Figure 1] This is a side view of a barge according to an embodiment of the present invention. [Figure 2] This is a view of the barge from the rear. [Figure 3] This is a schematic cross-sectional view along the line III-III shown in Figure 1. [Figure 4] This figure shows an example of a thruster. [Figure 5] This figure shows a barge according to this embodiment on the left and a barge according to a comparative example on the right. [Figure 6] This diagram shows the movement of the thrusters when a crane lifts a load. [Figure 7] This diagram shows the movement of the thrusters when the angle of the crane is adjusted while handling cargo. [Figure 8] This diagram illustrates the water flow caused by the thruster. [Figure 9] This is a diagram showing a modified barge. [Modes for carrying out the invention]

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the terms "front" and "rear" correspond to one end side and the other end side in the longitudinal direction of the pontoon, and the terms "left" and "right" correspond to the width direction based on the view of the pontoon from the rear side to the front side, and the terms "upper" and "lower" correspond to the up-and-down direction of the pontoon. In the following description, the front-rear direction may be referred to as "front-rear direction D1", and the width direction may be referred to as "width direction D2".

[0016] FIG. 1 and FIG. 2 are diagrams showing an example of a pontoon 100 according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view taken along line III-III shown in FIG. 1. FIG. 1 is a side view of the pontoon 100. FIG. 2 is a view of the pontoon 100 seen from the rear side. As shown in FIGS. 1 and 2, the pontoon 100 is a structure that floats on the water surface in the open ocean, offshore, bay, river, lake, etc. and performs predetermined operations. The pontoon 100 includes a hull 1, a crane 2, an on-board structure 3, and a thruster 4.

[0017] The hull 1 is a floating body that floats on the water surface WF and has a part of the bottom side disposed in the water. The hull 1 has an internal space for storing ballast water. The hull 1 includes a main body portion 10 and a bottom side portion 12 having a plurality of recesses 11. The main body portion 10 has a flat rectangular parallelepiped shape that extends in the front-rear direction D1 and the width direction D2. The upper surface of the main body portion 10 is configured as the upper deck 1a of the hull 1. The upper deck 1a is disposed above the water surface WF. The main body portion 10 has outer peripheral edge portions 1c, 1d, 1e, 1f. The outer peripheral edge portion 1c is the left edge of the hull 1. The outer peripheral edge portion 1d is the right edge of the hull 1. The outer peripheral edge portion 1e is the rear edge of the hull 1. The outer peripheral edge portion 1f is the front edge of the hull 1. The bottom side portion 12 is provided on the bottom side of the main body portion 10. The bottom side portion 12 is disposed below the water surface WF, that is, in the water. The lower surface of the bottom side portion 12 corresponds to the bottom 1b of the hull 1.

[0018] The recess 11 is a portion that depresses upward from the bottom of the hull 1b. In the present embodiment, the hull 1 has recesses 11A and 11B extending in the front-rear direction D1 and recesses 11C and 11D extending in the width direction D2. In the present embodiment, the plurality of recesses 11A, 11B, 11C, and 11D are provided along the outer peripheral edges 1c, 1d, 1e, and 1f of the hull 1. The recess 11A extends in the front-rear direction D1 along the left outer peripheral edge 11c. The recess 11B extends in the front-rear direction D1 along the right outer peripheral edge 11d. The recess 11C extends in the width direction D2 along the rear outer peripheral edge 11e. The recess 11D extends in the width direction D2 along the front outer peripheral edge 11f.

[0019] The recess 11 has an upper portion 11a and a side portion 11b. In the present embodiment, the upper portion 11a is constituted by the lower surface of the main body portion 10. The upper portions 11a of the respective recesses 11A, 11B, 11C, and 11D constitute the same rectangular plane on the lower surface of the main body portion 10 (see FIG. 3). The side portion 11b constitutes the inner peripheral side wall portion of the recess 11. The side portion 11b is constituted by the outer peripheral side surface of the bottom side portion 12. Note that the recess 11 has no wall portion on the outer peripheral side and is open to the outside. The side portion 11b has an inclined surface that inclines so as to widen toward the outer peripheral side from the bottom of the hull 1b to the upper portion 11a. Note that the inclination angle of the inclined surface of the side portion 11b is not particularly limited. Also, the side portion 11b does not have to be inclined and may be a surface extending in the vertical direction.

[0020] Compared to a basic hull of the same displacement volume that does not have multiple recesses 11A, 11B, 11C, 11D, the position of the bottom 1b of the hull 1 from the water surface WF is positioned lower. The left side of Figure 5 shows the barge 100 according to this embodiment, and the right side shows the barge 200 according to a comparative example. Under the condition that the displacement volume of hull 1 and the displacement volume of the basic hull 201 are the same, the basic hull 201 has a rectangular parallelepiped shape and does not have any of the recesses 11A, 11B, 11C, 11D. The area of ​​the upper deck 1a and the upper deck 201a are assumed to be the same. That is, the shape and size near the upper end of the basic hull 201 are the same shape and size as the main body 10 of hull 1. As shown in Figure 5, the height from the water surface WF of the upper deck 1a of hull 100 is the same as the height from the water surface WF of the upper deck 201a of the basic hull 201 of barge 200. In the hull 1, the volumes of the recesses 11A, 11B, 11C, and 11D are added to the lower end of the bottom side portion 12. Therefore, the position of the bottom 1b from the water surface WF is lower than the position of the bottom 201b from the upper deck 201a of the barge 200 in the comparative example. If a reference line SL1 is set horizontally with respect to the bottom 1b of the hull 1, the bottom 201b of the barge 200 in the comparative example is set higher than the reference line SL1.

[0021] Crane 2 is a device installed on the upper deck 1a for loading and unloading cargo. Crane 2 has a support section 17 installed on the upper deck 1a and a boom 18 extending upward from the support section 17. The tip 18a of the boom 18 is the part that suspends cargo. The boom 18 is rotatable with the support section 17 as the pivot point. As a result, when the boom 18 is raised, the tip 18a of the boom 18 moves toward the inner circumference of the hull 1, approaching the hull 1. When the boom 18 is lowered, the tip 18a of the boom 18 moves toward the outer circumference, away from the hull 1. As shown in Figure 2, the barge 100 has two cranes 2, but the number of cranes 2 is not particularly limited. The superstructure 3 is a structure installed on the upper deck 1a of the hull 1.

[0022] The thrusters 4 are mechanisms for maintaining position during operation, provided on the upper part 11a of each recess 11A, 11B, 11C, and 11D. In this embodiment, the barge 100 is equipped with four thrusters 4A, 4B, 4C, and 4D. The thrusters 4 are provided so as to extend downward from the upper part 11a. For example, a mechanism like the one shown in Figure 4 may be used as the thruster 4. The thruster 4 shown in Figure 4 is a mechanism known as a side thruster. The thruster 4 has a cylindrical body 41 and a propeller 42 provided inside the cylindrical body 41. The cylindrical body 41 and the propeller 42 are arranged so that their central axes face horizontal. Therefore, by rotating the propeller 42 in water and generating a water flow, thrust can be generated in any direction in the horizontal direction. The cylindrical body 41 and the propeller 42 rotate around a rotation axis 43 that extends in the vertical direction. This allows the thruster 4 to change the direction in which it generates thrust around the rotation axis 43.

[0023] Referring to Figure 3, the positions of thrusters 4A, 4B, 4C, and 4D will be explained. For ease of understanding, the internal area of ​​the bottom section 12 is hatched in Figure 3. As shown in Figure 3, thruster 4A is located at the corner between the left recess 11A and the rear recess 11C. Thruster 4B is located at the corner between the right recess 11B and the rear recess 11C. Thruster 4C is located at the corner between the left recess 11A and the front recess 11D. Thruster 4D is located at the corner between the right recess 11B and the front recess 11D. With this arrangement, the water flow generated by thrusters 4A and 4B towards the front avoids interference with the bottom section 12 and flows forward along the recesses 11A and 11B. The water flow generated by thrusters 4C and 4D towards the rear avoids interference with the bottom section 12 and flows backward along the recesses 11A and 11B. The water flow generated by thrusters 4A and 4C towards the right avoids interference with the bottom section 12 and flows to the right along the recesses 11C and 11D. The water flow generated by thrusters 4B and 4D towards the left avoids interference with the bottom section 12 and flows to the left along the recesses 11C and 11D.

[0024] Next, the manner in which thrust is generated by the thruster 4 will be explained. The thruster 4 generates thrust in the opposite direction to the external force acting on the crane 2 during operation. Refer to Figure 6 to see the movement of the thruster 4 when the crane 2 lifts the load 30. The upper part of Figures 6(a) and (b) is a side view of the barge 100, and the lower part is a cross-sectional view of the barge 100 seen from below. In the upper part of Figures 6(a) and (b), the hatched areas are the areas that receive pressure from the side wind. The center of the external force CP1 is shown. As shown in Figure 6(a), the barge 100 receives an external force to the left. When the thrusters 4A, 4B, 4C, and 4D are maintaining their position, they generate thrusts TF1A, TF1B, TF4C, and TF4D to the right to balance the external force OF1 so that the orientation and position of the barge 100 do not change. To maintain the position of the barge 100, thrust is generated from each thruster 4 such that the moment MO1 of the external force OF1 and the moment MT1 of the thrusts TF1A, TF1B, TF4C, and TF4D are balanced at the center of gravity G. Also, the sum of the external forces OF1 at the center of gravity G, OF1T, is balanced by the sum of the thrusts TF1A, TF1B, TF1C, and TF1D, TF1T. At this time, the sum of the thrusts TF12T is directed to the right, which is opposite to the sum of the external forces OF1T.

[0025] As shown in Figure 6(b), when an external force is applied from the side and an attempt is made to lift the load 30, the displacement and wind pressure area change, and the center of the external force, such as the current and wind, shifts (center CP2). Also, as the wind pressure area increases, the external force also changes (external force OF2). Thus, when the load 30 is lifted, the draft deepens by the weight of the load 30, and the wind pressure area changes, so the center CP2 of the external force OF2 and the applied external force OF2 change. Since the center CP2 of the external force OF2 is farther from the center of gravity G, the moment MO2 of the external force OF2 also changes. Therefore, the output and direction of thrusters 4A, 4B, 4C, and 4D are adjusted to adjust the thrusts TF2A, TF2B, TF2C, and TF2D. In addition, adjustments are made so that the moment MO2 of the external force OF2 and the moment MT2 of the thrusts TF2A, TF2B, TF2C, and TF2D are balanced. Thrusters 4A and 4B generate small thrusts TF2A and TF2B to the left, while thrusters 4C and 4D generate large thrusts TF2C and TD2D to the right. In this case, the total thrust TF2T is directed to the right, which is the opposite direction to the total external force OF2T.

[0026] As shown in Figure 7, when the thruster 4 is maintaining its position, it generates thrust to balance the external force so that the orientation and position of the barge 100 do not change. In this case, when an external force is applied from the side, if the angle of the crane 2 is adjusted when handling the cargo 30, the position of the cargo 30 changes, and the center of the area subjected to wind pressure shifts. Therefore, the output and orientation of the forward and aft thrusters 4 are adjusted to balance the force and moment of the external force and the thrust. Figure 7(a) shows the same state as Figure 6(b). As shown in Figure 7(b), the angle of the crane 2 is adjusted to raise the cargo 30 higher. In this case, the center of the external force changes. In this case, the magnitude of the external force OF3 is the same as that of the external force OF2, but the center CP3, which is the position where it acts, approaches the center of gravity G. Therefore, the output and orientation of the thrusters 4A, 4B, 4C, and 4D are adjusted to adjust the thrusts TF3A, TF3B, TF3C, and TF3D. Furthermore, the moment MO3 of the external force OF3 is adjusted to balance the moment MT3 of the thrusts TF3A, TF3B, TF3C, and TF3D. Thrusters 4A and 4B generate small thrusts TF3A and TF3B to the right, while thrusters 4C and 4D generate larger thrusts TF3C and TD3D to the right (but smaller than thrusts TF2C and TD2D). At this time, the total thrust TF3T is directed to the right, which is the opposite direction of the total external force OF3T.

[0027] Next is a diagram showing the operation and effects of the barge 100 according to this embodiment.

[0028] In the barge 100 according to this embodiment, the hull 1 has a plurality of recesses 11 that are recessed upward from the bottom 1b and extend in the width direction D2 and the longitudinal direction D1. The hull 1 also has thrusters 4 provided on the upper part 11a of each recess 11. This reduces the amount that the thrusters 4 protrude from the bottom 1b, or makes it possible to have a structure in which the thrusters 4 do not protrude from the bottom 1b. Furthermore, the position of the bottom 1b of the hull 1 is lower than that of a basic hull 201 (see the right side of Figure 5) with the same displacement volume but without the plurality of recesses 11.Therefore, the hull 1 can be structured in such a way that the parts of the hull 1 other than the recesses 11 are generally lowered.As a result, the center of gravity of the hull 1 can be lowered.

[0029] As shown in Figure 5, by providing a recess 11 that slopes upward from the bottom 1b of the hull, the position of the bottom 1b becomes lower than the bottom 201b of the basic hull 201 without changing the width, length, or displacement, making it possible to lower the center of gravity G of the hull 1. When the cargo 30 is lifted by the crane 2, ballast water is loaded into the aft ballast tank 40 as a counterweight at the rear. At this time, in the barge 100, the position of the ballast tank 40 is also set lower than the ballast tank 40 of the basic hull 201, in accordance with the hull shape, making it possible to lower the center of gravity GB. Since the waterline shape has not been changed from the barge 200 of the comparative example, the amount of movement of the point of application of buoyancy when the barge 100 is tilted does not change from the shape of the barge 200 of the comparative example.

[0030] The hull 1 may have recesses 11C and 11D extending in the width direction D2, and recesses 11A and 11B extending in the longitudinal direction D1. In this case, the water flow generated by the thruster 4 can exit in the width direction D2 through the recesses 11C and 11D extending in the width direction D2, while avoiding interference with the hull 1. Also, the water flow generated by the thruster 4 can exit in the width direction D2 through the recesses 11A and 11B extending in the longitudinal direction D1, while avoiding interference with the hull 1.

[0031] Multiple recesses 11 may be provided along the outer edge of the hull 1. In this case, the water flow generated by the thruster 4 passes through the recesses 11, making it easier to avoid interference with the hull 1.

[0032] For example, as shown in Figure 8(a), in the barge 100 according to this embodiment, interference between the water flow from the thrusters 4 and the bottom side portion 12 of the hull 1 can be reduced without the thrusters 4 protruding from the bottom 1b, so that greater thrust can be generated against external forces from any direction. On the other hand, the crane-holding vessel 300 according to the modified example shown in Figure 8(b) has a rear recess 11C and is equipped with thrusters 4A and 4B, but does not have other recesses 11A, 11B, and 11D. In addition, a thruster 4F is provided on the front side that protrudes from the bottom 1b when in operation. In this crane-holding vessel 300, during DPS operation, depending on the direction of the applied external force, the thrust from the bottom side portion 12 of the hull 1 may interfere with the thrust from the thrusters 4A and 4B, and it may not be possible to generate 100% thrust. For example, in Figure 8(b), when the thrusters 4A and 4B generate thrust forward, the water flow interferes with the bottom side portion 12. Furthermore, in order to generate 100% thrust in thruster 4F, it is necessary to position it so that it protrudes from the bottom of the hull 1b, but this requires a complex mechanism such as providing a storage compartment 51 to make it retractable.

[0033] The hull is equipped with a crane, and thruster 4 may generate thrust in the opposite direction to the external force acting on the crane 2 during operations. In this case, even if an external force acts on the hull, the thrust from thruster 4 can maintain its position.

[0034] The thrusters 4 may control their thrust so that the moment of the external force balances the thrust moment from each thruster 4. This allows the thrusters 4 to generate thrust that maintains the position of the hull 1 even when an external force acts on it.

[0035] The thruster 4 may control its thrust to counteract the moment of external forces that vary based on the angle of the crane 2. This allows the thruster 4 to generate thrust that maintains the position of the hull 1 even when external forces that vary based on the angle of the crane 2 are acting on it.

[0036] The present invention is not limited to the embodiments described above.

[0037] For example, the shape of the hull 1 is not limited to the embodiments described above. For example, as shown in Figure 9, a flat plate portion 13 may be provided on the lower end side of the bottom portion 12. By providing the flat plate portion 13 in a manner that does not protrude outward beyond the outer edge of the main body portion 10, the rolling motion of the barge 100, such as lateral and vertical motion, can be suppressed.

[0038] Furthermore, the number of thrusters is not limited to the embodiments described above. For example, the thrusters 4 provided at the four corners only need to be located at least diagonally opposite each other. For example, only thrusters 4B and 4C may be provided, or only thrusters 4A and 4D may be provided. In addition, the location and shape of the recesses are not limited to the embodiments described above. [Explanation of Symbols]

[0039] 1...hull, 2...crane, 4A,4B,4C,4D...thruster, 11A,11B,11C,11D...recess, 100...barge.

Claims

1. A hull having multiple recesses that curve upwards from the bottom, Each of the aforementioned recesses is provided with a thruster for maintaining its position during operation, The hull is a barge in which the position of the bottom of the hull from the water surface is positioned lower than that of a basic hull of the same displacement volume that does not have the plurality of recesses.

2. The barge according to claim 1, wherein the hull has the recess extending in the width direction and the recess extending in the longitudinal direction.

3. The barge according to claim 2, wherein the plurality of recesses are provided along the outer peripheral edge of the hull.

4. The aforementioned hull is equipped with a crane. The barge according to claim 1, wherein the thruster generates thrust in the opposite direction to the external force acting on the crane during operation.

5. The barge according to claim 4, wherein the thrusters control the thrust so that the moment of the external force and the moment of thrust from each thruster are in balance.

6. The barge according to claim 5, wherein the thruster controls the thrust to counteract the moment of the external force which changes based on the angle of the crane.

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