Floating structures

Abstract

To reduce the weight of a floating structure.SOLUTION: A floating structure 2 comprises a bottom part, a first side wall part 211, multiple strength members 214, and a second side wall part 212. The first side wall part 211 extends upward from the periphery of the bottom part over the whole circumference of the bottom part. The multiple strength members 214 are installed on the internal side face of the first side wall part 211. The second side wall part 212 is fixed to the external side face of the first side wall part 211 in a part of the periphery of the first side wall part 211 in a plan view. The second side wall part 212 is curved so as to be convex outward from the first side wall part 211. Both ends of the second side wall part 212 in the plan view are fixed to the external side face of the first side wall part 211 at the opposing position across two strength members 214 among the multiple strength members 214 and the first side wall part 211. The middle part of the second side wall part 212 in the plan view is separated toward the outside from the first side wall part 211. The floating structure 2 can be lighter as a result.SELECTED DRAWING: Figure 3

Description

Technical Field

[0004] , ,

[0005] , ,

[0001] The present invention relates to a floating structure moored by a mooring line.

Background Art

[0002] Conventionally, floating structures floating on the sea surface such as buoys and floating fish reefs are moored to the seabed by mooring lines. For example, Patent Document 1 discloses a floating structure having an octagonal columnar main floating body and a floating structure having a normal ship shape. When the floating structure having a ship shape faces the bow upward with respect to the waves, the fluid resistance is reduced as compared with an octagonal columnar or cylindrical floating structure, and the mooring tension acting on the mooring line is also reduced. As a result, the diameter of the mooring line can be reduced, and the cost of the mooring line may be reduced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a floating structure having a ship shape, since the shape is more complicated than an octagonal columnar or cylindrical floating structure, the internal structure for ensuring the strength of the floating structure becomes complicated. As a result, the weight of the floating structure increases, and the manufacturing cost of the floating structure may increase. Therefore, even if the cost of the mooring line is reduced, there is a limit to the cost reduction of the mooring system including the floating structure and the mooring line. For this reason, in a floating structure having a ship shape, weight reduction is required. Further, in a floating structure having a shape other than a ship shape, weight reduction of the floating structure is beneficial in various aspects such as reduction of manufacturing cost and simplification of transportation.

[0005] The present invention has been made in view of the above problems, and an object thereof is to reduce the weight of a floating structure. [Means for solving the problem]

[0006] One aspect of the present invention is a floating structure moored by a mooring line, having a floating body extending in the front-rear direction. The floating body has a bottom and the bottom All Over the course of the week Before Note bottom A first side wall portion extending upward from the peripheral edge, and a plurality of strength members provided on the inner surface of the first side wall portion, On the outside of the first side wall, Around the first side wall in a plan view It is continuously installed around the entire circumference. , Each It is fixed to the outer surface of the first side wall and curves so as to be convex outward from the first side wall. multiple It comprises a side wall section. The inner body portion, formed by the bottom portion and the first side wall portion, is boat-shaped and extends in the front-rear direction. The plurality of side wall portions include a plurality of second side wall portions provided on both sides in the width direction of the intermediate portion between the front end and the rear end of the inner body portion, extending along the entire length of the intermediate portion. The aforementioned multiple Second side wall Each second side wall section The front and rear ends are fixed to the outer surface of the first side wall portion, facing two of the plurality of strength members with the first side wall portion in between, and are supported by the two strength members. each The central portion of the second side wall in the front-rear direction is spaced outward from the first side wall.

[0008] Embodiments of the present invention 2 is, 1 A floating structure, wherein the inner main body The aforementioned front end is, The bow section, in plan view, has a width that increases from the front to the rear. The intermediate portion of the inner main body is A parallel section that is continuous with the aft end of the aforementioned bow and whose width in the width direction in a plan view is constant in the front-rear direction. That is . A third aspect of the present invention is a floating structure according to aspect 2, wherein the plurality of second side wall portions include two second side wall portions adjacent in the front-rear direction in the parallel portion. The lengths of the two second side wall portions in the front-rear direction are different from each other. The amount of projection of the two second side wall portions in the width direction from the first side wall portion is the same for both of them.

[0010] Aspect 4 of the present invention is, 1 (Pattern Choose one of 1 to 3. That's fine. )of A floating structure, The plurality of second side wall portions are, The central plane of the main body, which passes through the center in the width direction of the inner main body and is perpendicular to the width direction, The surface Symmetric 1 pair The second side wall portion include.

[0011] Aspects of the present invention 5 are any one of Aspect 1 to 4 any one tsu a floating structure, wherein a portion of the first side wall portion , the plurality opposite to the second side wall portion at least one second side wall portion is flat.

[0012] Aspects of the present invention 6 are any one of Aspect 1 to 4 any one of them (any one of Aspect 1 to 5 may be sufficient). )of a floating structure, wherein a space provided between the first side wall portion and The aforementioned multiple the second side wall portion at least one second side wall portion is filled with a filling material having a specific gravity smaller than that of water.

[0014] Aspects of the present invention 7 is a floating structure moored by a mooring line, comprising two floating body main bodies arranged side by side in the width direction and each extending in the front - rear direction, and a connecting portion connecting the two floating body main bodies. Each of the two floating body main bodies includes a bottom portion, a first side wall portion extending upward from a peripheral edge portion of the bottom portion over the circumference, a plurality of strength members provided on an inner surface of the first side wall portion, All extending around Before the bottom a side wall portion fixed to an outer surface of the first side wall portion and curved so as to protrude outward from the first side wall portion. In each of the two floating body main bodies, an inner main body portion formed by the bottom portion and the first side wall portion is boat - shaped and extends in the front - rear direction. On the outside of the first side wall, In a plan view, around the first side wall portion It is continuously installed around the entire circumference. of Each the front end portion and the rear end portion of the second side wall portion are fixed to the outer surface of the first side wall portion so as to face each other with two strength members of the plurality of strength members sandwiching the first side wall portion, and are supported by the two strength members. multiple The plurality of side wall portions include a plurality of second side wall portions provided on both sides in the width direction of the intermediate portion between the front end and rear end of the inner main body portion, extending along the entire length of the intermediate portion. The multiple second side wall portion Each second side wall section each ​​The central portion of the second side wall portion in the front-rear direction is spaced outward from the first side wall portion.

Effects of the Invention

[0015] In the present invention, the floating structure can be lightened.

Brief Description of the Drawings

[0016] [Figure 1] It is a side view showing the configuration of a mooring system including a floating structure according to the first embodiment. [Figure 2] It is a side view of the floating structure. [Figure 3] It is a plan view of the floating structure. [Figure 4] It is a front view of the floating structure. [Figure 5] It is a plan view showing a part of the floating body main body in an enlarged manner. [Figure 6] It is a diagram showing the relationship between the circumferential angle and the drag force. [Figure 7] It is a diagram showing the relationship between the circumferential angle and the stress. [Figure 8] It is a diagram showing the relationship between the circumferential angle and the amount of material. [Figure 9] It is a plan view of the floating structure. [Figure 10] It is a plan view of the floating structure according to the second embodiment. [Figure 11] It is a side view of the floating structure according to the third embodiment. ​​​​​​​​​​​​​

[0018] The floating structure 2 is a structure that floats on the water surface 91, spaced upward from the seabed 92. When the floating structure 2 is installed on the sea, the water surface 91 and the seabed 92 are the sea surface and the seabed, respectively. The floating structure 2 is, for example, an observation buoy that is moored in a predetermined sea area to observe tsunamis and / or waves. The total length of the floating structure 2 is, for example, several meters to more than ten meters, and the total width of the floating structure 2 is, for example, several meters.

[0019] The mooring base 3 is, for example, a sinker (i.e., a weight) or anchor (i.e., an anchor with holding power) submerged in the seabed 92. Alternatively, the mooring base 3 may be a fixed structure pre-installed in the seabed 92. The mooring base 3 does not necessarily have to be directly fixed to the seabed 92; for example, it may be an object that is indirectly fixed to the seabed 92 underwater via another structure fixed to the seabed 92.

[0020] The mooring line 4 is a roughly linear member connecting the floating structure 2 and the mooring base 3. The mooring line 4 is, for example, a mooring rope, a mooring chain, or a mooring chain and a mooring rope connected together. The mooring rope is, for example, a rope made of synthetic fiber or a metal rope containing wire. In Figure 1, for illustrative purposes, the mooring line 4 is shown as a line. In the example shown in Figure 1, the floating structure 2 is moored to the mooring base 3 at one point by a single mooring line 4. The floating structure 2 may be moored at multiple points.

[0021] Figure 2 is a side view showing the floating structure 2. Figure 3 is a top view showing the floating structure 2. Figure 4 is a front view showing the floating structure 2. In Figures 2 to 4, three mutually orthogonal directions, the X, Y, and Z directions, are defined. The X and Y directions are parallel to the horizontal plane, and the Z direction is parallel to the direction of gravity. The floating structure 2 comprises a floating body 21 and superstructure equipment 23. The floating body 21 is the main body of the floating structure 2 that floats on the water surface 91. The floating body 21 is formed from, for example, stainless steel, aluminum alloy, FRP, etc. The superstructure equipment 23 consists of various equipment provided on the upper surface of the floating body 21.

[0022] The floating body 21 extends approximately parallel to the X direction (hereinafter referred to as the "front-rear direction") in Figures 2 to 4. The floating body 21 is a member that extends elongated in the front-rear direction and has a shape (so-called boat shape) that tapers towards the front end (i.e., the (+X) side end). The width of the floating body 21 in the width direction (hereinafter also simply referred to as "width") is maximum near the center in the front-rear direction. In the floating structure 2 illustrated in Figure 3, the floating body 21 also has a shape that tapers towards the rear end (i.e., the (-X) side end).

[0023] The tapering shape refers to a shape in which the width of the floating body 21 decreases as it approaches the front or rear end of the floating body 21 (i.e., the direction perpendicular to the front-rear direction and the direction of gravity, the Y direction in Figures 2 to 4). In this case, the width at the front or rear end of the floating body 21 may gradually decrease as it approaches the front or rear end of the floating body 21, or it may decrease overall while including a portion that increases slightly in a part of the front-rear direction.

[0024] As illustrated in Figures 2 to 4, the width of the floating body 21 gradually decreases as it approaches the front end. Similarly, the width of the floating body 21 gradually decreases as it approaches the rear end. The shape of the floating body 21 is, for example, substantially symmetrical with respect to a hypothetical plane of symmetry perpendicular to the front-to-back direction at the center of the front-to-back direction (i.e., the longitudinal direction) (i.e., substantially front-to-back symmetrical).

[0025] The superstructure 23 consists of various devices and equipment installed to suit the intended use of the floating structure 2. As described above, when the floating structure 2 is used as an observation buoy for observing tsunamis and waves, the superstructure 23 includes, for example, a GPS (Global Positioning System) receiver for acquiring the three-dimensional movement of the floating structure 2. Based on the movement of the floating structure 2 acquired by the GPS receiver, fluctuations in the water surface 91 (e.g., waves, tide level, tsunami, etc.) are determined. The superstructure 23 may also include, for example, solar panels for supplying power to the GPS receiver, etc.

[0026] Figure 5 is a plan view showing an enlarged portion of the central part in the front-rear direction of the floating body 21 shown in Figure 3. As shown in Figures 2 to 5, the floating body 21 comprises a first side wall portion 211, a second side wall portion 212, a bottom portion 213, and a strength member 214.

[0027] The bottom portion 213 is a roughly plate-shaped portion that is elongated in the front-to-back direction and forms the lower end of the floating body 21 (i.e., the (-Z) side end). The bottom portion 213 is, for example, a roughly planar portion that is roughly perpendicular to the vertical direction (i.e., the Z direction). In the examples shown in Figures 2 and 4, the front and rear ends of the bottom portion 213 are inclined surfaces that gradually slope upward as they approach the front and rear ends of the floating body 21. The width of the bottom portion 213 in plan view gradually decreases at the front end of the floating body 21 as it approaches the front end, and gradually decreases at the rear end of the floating body 21 as it approaches the rear end.

[0028] The first side wall portion 211 is a substantially plate-shaped member that extends upward from the periphery of the bottom portion 213 and constitutes the side wall portion of the floating body 21. The first side wall portion 211 is provided around the entire circumference of the bottom portion 213. The first side wall portion 211 is a circumferential portion in which, for example, a plurality of substantially flat plate-shaped members extending substantially parallel in the vertical direction from the periphery of the bottom portion 213 are continuous along the periphery of the bottom portion 213. In plan view, the width of the circumferential first side wall portion 211 gradually decreases towards the front end of the floating body 21 and gradually decreases towards the rear end of the floating body 21.

[0029] In the following description, the structure composed of the bottom portion 213 and the first side wall portion 211 will be referred to as the "inner body portion 210". In the floating body portion 21 illustrated in Figures 2 to 4, the inner body portion 210 is a ship shape extending in the front-rear direction. If we call the imaginary plane passing through the center of the inner body portion 210 in the width direction and perpendicular to the width direction the body center plane, then the inner body portion 210 has a shape that is substantially symmetrical with respect to the body center plane. The upper end opening of the inner body portion 210 is closed by a substantially flat upper deck 217.

[0030] The inner hull section 210 comprises a bow section 201, a parallel section 202, and a stern section 203. The bow section 201 is the front end of the inner hull section 210, and the stern section 203 is the rear end of the inner hull section 210. The parallel section 202 is a central section located between the bow section 201 and the stern section 203, and is continuous in the longitudinal direction with the rear end of the bow section 201 and the front end of the stern section 203.

[0031] The width of the bow section 201 in a plan view gradually increases from the front end of the bow section 201 (i.e., the front end of the inner main body section 210) toward the rear. The width of the stern section 203 in a plan view gradually increases from the rear end of the stern section 203 (i.e., the rear end of the inner main body section 210) toward the front. The width of the parallel section 202 in a plan view is the maximum width of the inner main body section 210 and is substantially constant in the longitudinal direction. The cross-sectional shape of the parallel section 202 perpendicular to the longitudinal direction is substantially the same at each position in the longitudinal direction. In other words, the parallel section 202 is a section in which parts with the same cross-sectional shape perpendicular to the longitudinal direction are continuous for a predetermined length in the longitudinal direction. By providing the parallel section 202, the manufacturing of the inner main body section 210 can be simplified. Note that in the inner main body section 210, the width of the stern section 203 in a plan view may be substantially constant in the longitudinal direction. Furthermore, in the inner body portion 210, the parallel portion 202 is not provided, and the width of the inner body portion 210 may be maximized at only one position in the front-to-back direction.

[0032] Multiple reinforcing members 214 are provided on the inner surface of the first side wall portion 211 (i.e., the surface facing the space enclosed by the circumferential first side wall portion 211). The multiple reinforcing members 214 are arranged along the inner surface of the first side wall portion 211, spaced apart from each other in the front-rear direction. The multiple reinforcing members 214 are arranged at approximately equal intervals in the front-rear direction (for example, at intervals of 0.5m to 2m). Each reinforcing member 214 protrudes from the inner surface of the first side wall portion 211 toward the inside of the circumferential first side wall portion 211, approximately perpendicular to the inner surface.

[0033] Each reinforcing member 214 is, for example, a substantially flat plate-shaped member that is substantially perpendicular to the front-rear direction. Each reinforcing member 214 is, for example, a transverse bulkhead that partitions the internal space of the inner main body portion 210 in the front-rear direction. In this case, a reinforcing member 214 provided on one side of the first side wall portion 211 in the width direction from the main body center plane and a reinforcing member 214 provided on the other side of the first side wall portion 211 in the width direction from the main body center plane at the same position in the front-rear direction as the said reinforcing member 214 are the same transverse bulkhead.

[0034] Furthermore, each strength member 214 may be part of a so-called horizontal frame. In this case, a strength member 214 provided on one side of the first side wall portion 211 in the width direction from the main body center plane and a strength member 214 provided on the other side of the first side wall portion 211 in the width direction from the main body center plane at the same position in the front-rear direction as the said strength member 214 are part of the same horizontal frame. The lower ends of the multiple strength members 214 provided on the one side and the lower ends of the multiple strength members 214 provided on the other side are connected to each other via multiple strength members (not shown) that are arranged in the front-rear direction on the upper surface of the bottom portion 213 and each extends in the width direction. Note that the multiple strength members 214 do not necessarily need to be arranged at equal intervals in the front-rear direction and may be arranged at unequal intervals.

[0035] The second side wall portion 212 is a curved plate-like portion that extends substantially parallel to the vertical direction on the outside of the circumferential first side wall portion 211. Together with the first side wall portion 211, the second side wall portion 212 constitutes the side wall portion of the floating body 21. In the example shown in Figure 3, a plurality of second side wall portions 212 are continuously provided circumferentially on the outside of the first side wall portion 211, surrounding the entire circumference of the first side wall portion 211 in a plan view. Each second side wall portion 212 is positioned on a part of the circumferential direction of the first side wall portion 211 in a plan view. In the example shown in Figure 3, among the plurality of second side wall portions 212, the plurality of second side wall portions 212 located on one side of the main body center plane and the plurality of second side wall portions 212 located on the other side of the main body center plane are arranged symmetrically with respect to the main body center plane. Furthermore, the shapes of the multiple second side wall portions 212 arranged in the parallel portion 202 are substantially the same. However, the multiple second side wall portions 212 may include second side wall portions 212 with different shapes.

[0036] In the bow section 201, the parallel section 202, and the stern section 203, the second side wall section 212 is fixed to the outer surface of the first side wall section 211 at its front and rear ends (i.e., both ends of the second side wall section 212 in a plan view). More specifically, the front and rear ends of each second side wall section 212 are fixed to the outer surface of the first side wall section 211 at positions where they face two of the multiple strength members 214, sandwiching the first side wall section 211. Other strength members 214 may or may not be provided between the front and rear ends of one second side wall section 212 and the two strength members 214 facing them in the longitudinal direction. In other words, one second side wall portion 212 may face only two strength members 214 located at approximately the same position in the front-rear direction as its front and rear ends, with the first side wall portion 211 in between, or it may face three or more strength members 214, including the two strength members 214, with the first side wall portion 211 in between. In the example shown in Figure 3, the two strength members 214 facing the front and rear ends of one second side wall portion 212 are two strength members 214 adjacent to each other in the front-rear direction. Also, the rear end of one second side wall portion 212 and the front end of a second side wall portion 212 adjacent to the rear of that first second side wall portion 212 face each other with the same strength member 214 and the first side wall portion 211 in between. Furthermore, the front and rear ends of the second side wall portion 212 only need to be substantially opposite the reinforcing member 214 with the first side wall portion 211 in between, and may be fixed to the outer surface of the first side wall portion 211 at a position slightly offset in the front-rear direction from the reinforcing member 214.

[0037] Each second side wall portion 212 is curved so as to be convex outward from the first side wall portion 211, and the central part of each second side wall portion 212 in the longitudinal direction is spaced outward from the circumferential first side wall portion 211 in a plan view. As a result, a space 215 extending in the vertical direction is formed between each second side wall portion 212 and the first side wall portion 211. The upper and lower ends of the space 215 are open to the outside. The upper and / or lower ends of the space 215 may be closed. In the first side wall portion 211 illustrated in Figure 3, the portion of the parallel section 202 facing each second side wall portion 212 is substantially flat. In addition, the portion of the first side wall portion 211 facing each second side wall portion 212 in the bow section 201 and the stern section 203 is also substantially flat.

[0038] The shape of each second side wall portion 212 in plan view is, for example, approximately arc-shaped. In this case, the inscribed angle of the approximately arc-shaped second side wall portion 212 in plan view is preferably 60° to 90°. In the example shown in Figure 5, the inscribed angle θ of the second side wall portion 212 is approximately 60°. Furthermore, the shape of the space 215 provided between the second side wall portion 212 and the first side wall portion 211 is approximately bow-shaped in plan view. Note that the inscribed angle θ may be less than 60° or greater than 90°.

[0039] As described above, in the example shown in Figure 3, the shapes of the multiple second side wall portions 212 arranged in the parallel portion 202 are substantially the same. That is, the lengths in the front-rear direction of the multiple second side wall portions 212 arranged in the parallel portion 202 are substantially the same, and the amount of projection of the multiple second side wall portions 212 from the first side wall portion 211 is substantially the same. Therefore, in the case of multiple second side wall portions 212 arranged side by side in the front-rear direction in the parallel portion 202, the imaginary straight line connecting the maximum projections of each of the multiple second side wall portions 212 (i.e., the parts furthest from the first side wall portion 211 in the width direction) is substantially parallel in the front-rear direction.

[0040] The amount of protrusion of the second side wall portion 212 from the first side wall portion 211, as described above, is the distance between the part of the second side wall portion 212 that is furthest from the first side wall portion 211 and the first side wall portion 211, in a plan view with respect to the direction perpendicular to the first side wall portion 211. For example, in the case of a second side wall portion 212 arranged in a parallel portion 202, the amount of protrusion of the second side wall portion 212 from the first side wall portion 211 is the amount of protrusion in the width direction, and is the distance in the width direction between the part of the second side wall portion 212 that is furthest from the first side wall portion 211 and the first side wall portion 211.

[0041] Focusing on the portion of the floating body 21 where a second side wall portion 212 is provided, as described above, both ends of the second side wall portion 212 in the front-rear direction are fixed to two strength members 214 via the first side wall portion 211 and supported by the two strength members 214. In addition, both ends of the portion of the first side wall portion 211 facing the second side wall portion 212 in the front-rear direction are fixed to both ends of the second side wall portion 212 in the front-rear direction and are supported by the two strength members 214.

[0042] In other words, the floating body 21 is configured as a tied arch structure by a curved plate-shaped second side wall portion 212 (i.e., an arch) and a portion of the first side wall portion 211 that faces the second side wall portion 212 (i.e., a tie). Therefore, the plate thickness of the portion of the first side wall portion 211 that faces the second side wall portion 212 can be made thinner than the plate thickness if the second side wall portion 212 were not provided. Furthermore, the sum of the plate thickness of the portion of the first side wall portion 211 that faces the second side wall portion 212 and the plate thickness of the second side wall portion 212 can be made thinner than the plate thickness of the first side wall portion 211 if the second side wall portion 212 were not provided. As a result, the weight of the floating structure 2 is reduced.

[0043] The plate thickness of the first side wall 211 and the second side wall 212 described above is usually determined by calculating the external forces acting on the side walls based on external conditions such as water flow and waves in the water area where the floating structure 2 is installed, and ensuring that the side walls can withstand these external forces. When the stress acting on the floating structure 2 was calculated using FEM (Finite Element Method) analysis, the stress acting on the first side wall 211 and the second side wall 212, respectively, was found to be approximately 3% of the stress acting on the first side wall 211 if the second side wall 212 were not provided. Therefore, the total plate thickness of the first side wall 211 and the second side wall 212 only needs to be approximately 6% or more of the plate thickness of the first side wall 211 if the second side wall 212 were not provided, and even including a margin for corrosion, the first side wall 211 and the second side wall 212 can be made significantly thinner.

[0044] When manufacturing the floating structure 2, for example, a plurality of panels intended to become the first side wall portion 211 and a plurality of second side wall portions 212 are prepared, and each second side wall portion 212 and the panel corresponding to the second side wall portion 212 are fixed by welding or the like to form a plurality of side wall elements. Subsequently, the floating structure 2 is formed by fixing the plurality of side wall elements to a plurality of horizontal bulkheads, which are a plurality of strength members 214 fixed to the bottom portion 213, by welding or the like. Alternatively, an inner main body portion 210 with a plurality of strength members 214 fixed inside may be formed in advance, and the floating structure 2 may be formed by fixing the plurality of second side wall portions 212 to the outer surface of the inner main body portion 210 by welding or the like.

[0045] Furthermore, the shape of the bottom portion 213 of the floating body 21 can be changed in various ways, such as a rounded U-shape or a V-shape with a pointed lower end. Also, the first side wall portion 211 and each second side wall portion 212 do not necessarily have to be parallel in the vertical direction; for example, they may be inclined surfaces that slope outward in the width direction as they rise from the bottom portion 213. The shape of the second side wall portion 212 in plan view is also not limited to a roughly arc shape and can be changed in various ways.

[0046] In the related technologies of this inventionIn the floating body 21, it is not necessarily required that multiple second side wall portions 212 be provided around the entire circumference of the first side wall portion 211; the second side wall portions 212 may be provided only around a portion of the first side wall portion 211. In this case, the number of second side wall portions 212 does not necessarily need to be multiple; there may be just one.

[0047] As described above, the floating structure 2 moored by the mooring line 4 comprises a bottom portion 213, a first side wall portion 211, a plurality of strength members 214, and a second side wall portion 212. The first side wall portion 211 extends upward from the peripheral edge of the bottom portion 213 around its entire circumference. The plurality of strength members 214 are provided on the inner surface of the first side wall portion 211. The second side wall portion 212 is fixed to the outer surface of the first side wall portion 211 in a portion of its periphery in a plan view. The second side wall portion 212 curves so as to be convex outward from the first side wall portion 211. In a plan view, both ends of the second side wall portion 212 are fixed to the outer surface of the first side wall portion 211 at positions where they face two of the plurality of strength members 214, with the first side wall portion 211 in between. Furthermore, the central part of the second side wall portion 212 in a plan view is spaced outward from the first side wall portion 211.

[0048] As a result, since the tied arch structure is formed by the second side wall portion 212 and the first side wall portion 211 as described above, the total plate thickness of the portion of the first side wall portion 211 facing the second side wall portion 212 and the second side wall portion 212 can be reduced. As a result, the floating structure 2 can be made lighter, and the manufacturing costs of the floating structure 2 and the mooring system 1 can be reduced.

[0049] As described above, it is preferable that the portion of the first side wall portion 211 facing the second side wall portion 212 be flat. This reduces the weight of that portion compared to when it is curved. Furthermore, the cost of bending the steel material is eliminated. As a result, the manufacturing cost of the floating structure 2 can be further reduced.

[0050] As described above, the inner main body portion 210, which is composed of the bottom portion 213 and the first side wall portion 211, is preferably ship-shaped and extends in the front-rear direction. This reduces the fluid resistance acting on the floating structure 2 compared to floating structures such as cylindrical structures, and thus reduces the mooring tension acting on the mooring line 4. As a result, the diameter of the mooring line 4 can be reduced, and the manufacturing cost of the mooring system 1 can be reduced. Furthermore, as described above, the plate thickness of the first side wall portion 211 and the second side wall portion 212 can be made thinner in the floating structure 2, so the above structure of the floating structure 2 is particularly suitable for ship-shaped floating structures, which tend to be heavier than floating structures such as cylindrical structures.

[0051] As described above, the inner main body portion 210 preferably comprises a bow portion 201 and a parallel portion 202. In the bow portion 201, the width in the width direction in a plan view increases from the front end to the rear. The parallel portion 202 is continuous with the rear end of the bow portion 201. In the parallel portion 202, the width in the width direction in a plan view is constant in the front-rear direction. Furthermore, the second side wall portion 212 is preferably fixed to the first side wall portion 211 in the parallel portion 202. This makes it possible to efficiently achieve weight reduction by thinning the portion of the first side wall portion 211 that faces the second side wall portion 212.

[0052] As described above, it is also preferable that the floating structure 2 further comprises another second side wall portion 212 fixed to the outer surface of the first side wall portion 211 adjacent to the second side wall portion 212 in the front-rear direction in the parallel portion 202. The other second side wall portion 212 is curved so as to be convex outward from the first side wall portion 211. In a plan view, both ends of the other second side wall portion 212 are fixed to the outer surface of the first side wall portion 211 at positions where they face two of the plurality of strength members 214, sandwiching the first side wall portion 211. In a plan view, the central part of the other second side wall portion 212 is spaced outward from the first side wall portion 211. It is preferable that the amount of protrusion of the other second side wall portion 212 in the width direction from the first side wall portion 211 is the same as the amount of protrusion of the second side wall portion 212 in the width direction from the first side wall portion 211. In this way, by making the protrusion amounts of the two adjacent second side wall portions 212 in the front-rear direction of the parallel portion 202 the same, it is possible to facilitate the docking of a ship with respect to the floating structure 2.

[0053] As described above, it is also preferable that the floating structure 2 further comprises another second side wall portion 212 which is symmetrical with respect to the second side wall portion 212 with respect to the central plane of the main body. The central plane of the main body is a plane that passes through the center in the width direction of the inner main body portion 210 and is perpendicular to the width direction. The other second side wall portion 212 is fixed to the outer surface of the first side wall portion 211 and is curved so as to be convex outward from the first side wall portion 211. In a plan view, both ends of the other second side wall portion 212 are fixed to the outer surface of the first side wall portion 211 at positions that face off against two of the plurality of strength members 214, with the first side wall portion 211 in between. In a plan view, the central part of the other second side wall portion 212 is spaced outward from the first side wall portion 211. This suppresses the difference in fluid resistance between the port and starboard sides of the ship-shaped floating structure 2, making it easier to orient the bow section 201 towards the wave side. As a result, the fluid resistance acting on the floating structure 2 can be further reduced, and the mooring tension acting on the mooring line 4 can be further reduced.

[0054] As described above, in the floating structure 2, it is preferable that a plurality of second side wall portions 212, including the second side wall portion 212, are provided around the entire circumference of the first side wall portion 211 in a plan view. Each of the plurality of second side wall portions 212 is fixed to the outer surface of the first side wall portion 211 and is curved so as to be convex outward from the first side wall portion 211. In a plan view, both ends of each second side wall portion 212 are fixed to the outer surface of the first side wall portion 211 at positions facing two of the plurality of strength members 214, with the first side wall portion 211 in between. In a plan view, the central part of each second side wall portion 212 is spaced outward from the first side wall portion 211. This makes it possible to make the first side wall portion 211 thinner around its entire circumference, and to further reduce the weight of the floating structure 2. As a result, the manufacturing costs of the floating structure 2 and the mooring system 1 can be further reduced.

[0055] As described above, the inscribed angle θ of the roughly arc-shaped second side wall 212 (see Figure 5) can be varied. Figure 6 shows the relationship between the inscribed angle θ and the drag force of the floating structure 2. In Figure 6, the horizontal axis represents the inscribed angle θ (°), and the vertical axis represents the drag force (N). This drag force (i.e., the fluid resistance acting on the floating structure 2) was calculated by CFD (Computational Fluid Dynamics) analysis, assuming a draft of 1.0 m for the floating structure 2 and a water flow velocity of 1.5 m / s around the floating structure 2. Furthermore, the inscribed angle θ of the second side wall 212 was changed while maintaining the length of the second side wall 212 in the longitudinal direction at a predetermined length (the same applies to Figures 7 and 8). From Figure 6, it can be seen that the drag force increases as the inscribed angle θ increases.

[0056] Figure 7 shows the relationship between the inscribed angle θ and the stress generated in the second sidewall 212. The horizontal axis of Figure 7 represents the inscribed angle θ (°), and the vertical axis represents the stress (MPa). The stress was calculated using FEM analysis. From Figure 7, it can be seen that as the inscribed angle θ increases, the stress generated in the second sidewall 212 decreases. Similarly, as the inscribed angle θ increases, the stress generated in the first sidewall 211 also decreases.

[0057] Figure 8 shows the relationship between the inscribed angle θ and the amount of material in the second side wall 212. The horizontal axis of Figure 8 represents the inscribed angle θ (°), and the vertical axis represents the amount of material per 10 mm of plate thickness (kg / 10 mm). This amount of material was calculated based on the length of the second side wall 212 (i.e., the length along the curved side of the second side wall 212). From Figure 8, it can be seen that as the inscribed angle θ increases, the amount of material in the second side wall 212 also increases.

[0058] The drag force shown in Figure 6 is preferable to be small from the viewpoint of reducing the diameter of the mooring line 4. The stress shown in Figure 7 is preferable to be small from the viewpoint of thinning the first side wall portion 211 and the second side wall portion 212. The amount of material shown in Figure 8 is preferable to be small from the viewpoint of reducing the manufacturing cost of the floating structure 2. Considering all of these factors, the inscribed angle θ is preferably 60° to 90°.

[0059] In the floating structure 2, as shown in Figure 9, it is preferable that the space 215 provided between the first side wall 211 and the second side wall 212 is filled with a filler material 216 having a specific gravity less than water. In Figure 9, parallel diagonal lines are drawn on the filler material 216 to facilitate understanding of the figure. In this case, the floating structure 2 can be miniaturized by utilizing the buoyancy of the filler material 216. In addition, since the strength of the side wall portion of the floating structure 2 is improved by the filler material 216, the plate thickness of the first side wall portion 211 and / or the second side wall portion 212 can be further reduced. As the filler material 216, for example, wood or foamed resin material can be used. The filler material 216 may be filled throughout substantially the entire space 215, or it may be partially filled in a part of the space 215. Furthermore, the filler material 216 may be filled in all of the multiple spaces 215, or it may be filled in only some of the spaces 215.

[0060] Next, a floating structure 2a according to a second embodiment of the present invention will be described. Figure 10 is a plan view showing the floating structure 2a. In the floating body 21a of the floating structure 2a, a second side wall portion 212a, which has a different length in the front-rear direction from the other second side wall portions 212, is provided in the parallel portion 202. The other structures of the floating structure 2a are the same as those of the floating structure 2 described above, and in the following description, the same reference numerals are used for each component of the floating structure 2a that corresponds to the components of the floating structure 2.

[0061] The floating structure 2a further comprises, in addition to the second side wall portion 212 fixed to the outer surface of the first side wall portion 211 in the parallel portion 202, another second side wall portion 212a fixed to the outer surface of the first side wall portion 211 adjacent to the second side wall portion 212 in the front-rear direction in the parallel portion 202. The second side wall portion 212a is curved so as to be convex outward from the first side wall portion 211. In a plan view, both ends of the second side wall portion 212a are fixed to the outer surface of the first side wall portion 211 at positions facing two of the plurality of strength members 214, with the first side wall portion 211 in between. In a plan view, the central part of the second side wall portion 212a is spaced outward from the first side wall portion 211. The length of the second side wall portion 212a in the front-rear direction is different from the length of the second side wall portion 212 described above. The amount of the second side wall portion 212a protruding from the first side wall portion 211 in the width direction is the same as the amount of the second side wall portion 212 protruding from the first side wall portion 211 in the width direction.

[0062] Thus, even if the lengths of the two adjacent second side wall sections 212 and 212a in the parallel section 202 are different in the longitudinal direction, by making the amount of protrusion in the width direction of the second side wall sections 212 and 212a the same, it is possible to facilitate the docking of a ship with respect to the floating structure 2a.

[0063] Next, a floating structure 2b according to a third embodiment of the present invention will be described. Figure 11 is a side view showing the floating structure 2b. Figure 12 is a plan view showing the floating structure 2. Figure 13 is a front view showing the floating structure 2. The floating structure 2b is a so-called catamaran (twin-hulled) type structure. The floating structure 2b comprises two floating bodies 21b and a connecting part 22b.

[0064] Each floating body 21b extends substantially parallel to the front-rear direction (i.e., the X direction). Two floating body 21b are arranged with a gap between them in the width direction (i.e., the Y direction). In other words, one floating body 21b is positioned to the side of the other floating body 21b, spaced apart. The shape of the two floating body 21b extends in the front-rear direction at the center of the width direction of the two floating body 21b and is substantially symmetrical with respect to a virtual plane of symmetry perpendicular to the width direction. Each floating body 21b is formed from, for example, stainless steel, aluminum alloy, FRP, etc.

[0065] In the examples shown in Figures 11 to 13, the shape and structure of each floating body 21b are substantially the same as the floating body 21 described above, except that they are slightly narrower in width. That is, each floating body 21b comprises a first side wall portion 211, a plurality of second side wall portions 212, a bottom portion 213, and a plurality of strength members 214. The bottom portion 213 is a substantially plate-shaped portion that is long in the front-rear direction and constitutes the lower end of the floating body 21b (i.e., the (-Z) side end). The first side wall portion 211 is a substantially plate-shaped member that extends upward from the peripheral edge of the bottom portion 213 and constitutes the side wall portion of the floating body 21b. The first side wall portion 211 is provided around the entire circumference of the bottom portion 213. The inner body portion 210, which is composed of the bottom portion 213 and the circumferential first side wall portion 211, is boat-shaped and extends in the front-rear direction.

[0066] Multiple second side wall portions 212 are provided continuously in a circumferential manner on the outside of the first side wall portion 211, surrounding the entire circumference of the first side wall portion 211 in a plan view. Each second side wall portion 212 is a plate-shaped portion that curves outward from the first side wall portion 211. Multiple second side wall portions 212 together with the first side wall portion 211 constitute the side wall portion of the floating body 21b. The front and rear ends of each second side wall portion 212 are fixed to the outer surface of the first side wall portion 211 at positions opposite to two of the multiple strength members 214 fixed to the inner surface of the first side wall portion 211, with the first side wall portion 211 in between.

[0067] In each floating body 21b, similar to the floating body 21, it is not necessary for multiple second side wall portions 212 to be provided around the entire circumference of the first side wall portion 211; the second side wall portions 212 may be provided only around a portion of the first side wall portion 211. In this case, the number of second side wall portions 212 does not necessarily have to be multiple; there may be just one.

[0068] The connecting section 22b connects the upper parts of the two floating body halves 21b above the waterline of the floating structure 2b (i.e., the upper waterline in the design). The connecting section 22b includes an upper deck 221b that connects the upper ends of the two floating body halves 21b (i.e., the (+Z) side ends). The upper deck 221b is a substantially flat plate-shaped member that is substantially vertical in the vertical direction and is positioned above the water surface. The upper deck 221b is, for example, a substantially rectangular member that extends over substantially the entire length in the front-rear direction of the two floating body halves 21b. The upper deck 221b covers substantially the entire upper surface of the two floating body halves 21b and the entire upper space between the two floating body halves 21b. The upper deck 221b is formed from, for example, stainless steel, aluminum alloy, FRP, etc. The upper equipment 23, such as the GPS receiver mentioned above, is provided on the upper deck 221b.

[0069] The upper deck 221b does not necessarily have to be roughly rectangular in shape, and may be a member of another shape (for example, roughly disc-shaped). In addition, the connecting section 22b may include other connecting members for connecting the two floating body 21b, in addition to the upper deck 221b, or in place of the upper deck 221b. Such other connecting members may be, for example, a truss structure formed by combining roughly straight steel members.

[0070] As described above, the floating structure 2b moored by the mooring line 4 (see Figure 1) comprises two floating body parts 21b aligned in the width direction and each extending in the front-rear direction, and a connecting part 22b connecting the two floating body parts 21b. Each of the two floating body parts 21b comprises a bottom portion 213, a first side wall portion 211, a plurality of strength members 214, and a second side wall portion 212. The first side wall portion 211 extends upward from the periphery of the bottom portion 213 over its entire circumference. The plurality of strength members 214 are provided on the inner surface of the first side wall portion 211. The second side wall portion 212 is fixed to the outer surface of the first side wall portion 211 in a portion of its periphery in a plan view, and curves so as to be convex outward from the first side wall portion 211.

[0071] In each of the two floating body bodies 21b, the inner body portion 210, which is composed of a bottom portion 213 and a first side wall portion 211, is boat-shaped and extends in the front-rear direction. In plan view, both ends of the second side wall portion 212 are fixed to the outer surface of the first side wall portion 211 at positions where they face two of the multiple strength members 214, sandwiching the first side wall portion 211. In plan view, the central portion of the second side wall portion 212 is spaced outward from the first side wall portion 211.

[0072] In each floating body 21b of the floating structure 2b, a tied arch structure is formed by the second side wall 212 and the first side wall 211, similar to the floating structure 2. This allows the total plate thickness of the portion of the first side wall 211 facing the second side wall 212 and the second side wall 212 to be reduced. As a result, the floating structure 2b can be made lighter, and the manufacturing costs of the floating structure 2b and the mooring system 1 (see Figure 1) can be reduced. Furthermore, because the inner body portion 210 of each floating body 21b is boat-shaped, the fluid resistance acting on the floating structure 2b is reduced, and the mooring tension acting on the mooring line 4 (see Figure 1) can be reduced. As a result, the diameter of the mooring line 4 can be reduced, and the manufacturing cost of the mooring system 1 can be further reduced.

[0073] Furthermore, since the floating structure 2b has a catamaran-type structure in which two floating bodies 21b are aligned in the width direction, the ratio of the length in the longitudinal direction to the width of each floating body 21b (so-called L / B) can be increased while maintaining the righting force of the floating structure 2b. As a result, the fluid resistance acting on the floating structure 2b is further reduced, and the diameter of the mooring line 4 can be made even smaller.

[0074] Various modifications are possible to the floating structures 2, 2a, and 2b described above.

[0075] In floating structure 2, the portion of the first side wall 211 facing the second side wall 212 does not necessarily have to be flat; for example, it may be curved or bent. The same applies to floating structures 2a and 2b.

[0076] In floating structure 2, the protrusion amounts of the multiple second side wall portions 212 in the parallel portion 202 do not necessarily have to be the same; they may be different. The same applies to floating structures 2a and 2b.

[0077] In the floating structure 2b, the number of floating bodies 21b is not limited to two; for example, three floating bodies 21b arranged in the width direction may be provided. In this case, the size and shape of the three floating bodies 21b may be the same or different. For example, the length in the front-to-back direction of the floating body 21b located in the center in the width direction may be longer than the lengths of the two floating bodies 21b located on either side in the width direction.

[0078] In floating structure 2, the shape of the inner main body 210 is not necessarily limited to a ship shape; for example, it may be a cylindrical or polygonal prism shape extending in the vertical direction. The same applies to floating structure 2a.

[0079] Floating structure 2 does not necessarily have to be used as an observation buoy for observing tsunamis and / or waves, and can be used for various purposes such as floating artificial reefs.

[0080] The configurations in the above embodiments and each modified example may be combined as appropriate, as long as they do not contradict each other. [Explanation of Symbols]

[0081] 2,2a,2b Floating structures 4. Mooring lines 21, 21a, 21b Floating body 22b Connection part 201 Fore part 202 Parallel section 210 Inner body part 211 First side wall section 212,212a 2nd side wall part 213 Bottom 214 Strengthening members 215 Space 216 Filler

Claims

1. A floating structure moored by a mooring line, It has a floating body that extends in the front-to-back direction, The floating body is, The bottom and, A first side wall portion extending upward from the peripheral edge of the bottom portion over the entire circumference of the bottom portion, Multiple reinforcing members provided on the inner surface of the first side wall portion, On the outside of the first side wall, a plurality of side wall portions are provided continuously around the entire circumference of the first side wall in a plan view, each fixed to the outer surface of the first side wall and curving so as to be convex outward from the first side wall, Equipped with, The inner body portion, which is composed of the bottom portion and the first side wall portion, is boat-shaped and extends in the front-rear direction. The plurality of side wall portions include a plurality of second side wall portions provided on both sides in the width direction of the intermediate portion between the front end and rear end of the inner main body portion, extending over the entire length of the intermediate portion. The front and rear ends of each of the plurality of second side wall portions are fixed to the outer surface of the first side wall portion, facing two of the plurality of strength members with the first side wall portion in between, and are supported by the two strength members. A floating structure characterized in that the central portion of each of the second side walls in the front-rear direction is spaced outward from the first side wall.

2. A floating structure according to claim 1, The front end of the inner main body is a bow section in which the width in the width direction in a plan view increases from the front end toward the rear. The floating structure is characterized in that the intermediate portion of the inner main body is a parallel portion that is continuous with the aft end of the bow and has a constant width in the width direction in a plan view in the front-rear direction.

3. A floating structure according to Claim 2, The plurality of second side wall portions include two second side wall portions adjacent to each other in the front-rear direction in the parallel portion. The lengths of the two second side wall portions in the front-rear direction are different from each other. A floating structure characterized in that the amount of protrusion in the width direction from the first side wall portion of the two second side wall portions is the same for all of them.

4. A floating structure according to claim 1, The floating structure is characterized in that the plurality of second side wall portions include a pair of second side wall portions that pass through the center in the width direction of the inner main body portion and are symmetrical with respect to the central plane of the main body perpendicular to the width direction.

5. A floating structure according to any one of claims 1 to 4, A floating structure characterized in that, of the first side wall portion, the portion facing at least one of the plurality of second side wall portions is flat.

6. A floating structure according to any one of claims 1 to 4, A floating structure characterized in that a space provided between the first side wall portion and at least one of the plurality of second side wall portions is filled with a filler material having a specific gravity less than that of water.

7. A floating structure moored by a mooring line, Two floating bodies are arranged in the width direction and each extends in the front-to-back direction, A connecting part that connects the two floating body bodies, Equipped with, Each of the two floating bodies is, The bottom and, A first side wall portion extending upward from the peripheral edge of the bottom portion over the entire circumference of the bottom portion, Multiple reinforcing members provided on the inner surface of the first side wall portion, On the outside of the first side wall, a plurality of side wall portions are provided continuously around the entire circumference of the first side wall in a plan view, each fixed to the outer surface of the first side wall and curving so as to be convex outward from the first side wall, Equipped with, In each of the two floating body parts, The inner body portion, which is composed of the bottom portion and the first side wall portion, is boat-shaped and extends in the front-rear direction. The plurality of side wall portions include a plurality of second side wall portions provided on both sides in the width direction of the intermediate portion between the front end and rear end of the inner main body portion, extending over the entire length of the intermediate portion. The front and rear ends of each of the plurality of second side wall portions are fixed to the outer surface of the first side wall portion, facing two of the plurality of strength members with the first side wall portion in between, and are supported by the two strength members. A floating structure characterized in that the central portion of each of the second side walls in the front-rear direction is spaced outward from the first side wall.

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