Boat landing, boat landing installation method, boat landing replacement method and offshore structure

Abstract

To provide a boat landing, a boat landing installation method, a boat landing replacement method, and an offshore structure capable of suppressing damage on a work craft.SOLUTION: A boat landing 100 installed on an offshore structure 200 supporting an offshore windmill is provided with: a buffer part 10 coming into contact with a ship; and an insertion part 20 inserted in a pipe part 210 provided on the offshore structure 200. The insertion part 20 is closer to a center of the offshore structure 200 than the buffer part 10 when viewed in a vertical direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a boat landing, a method for installing a boat landing, a method for replacing a boat landing, and an offshore structure. [Background technology]

[0002] A boat landing may be provided to allow a work vessel to come into contact with marine structures, such as jacket structures and monopile structures, located on the ocean. For example, Patent Document 1 discloses a replaceable fender mechanism (boat landing) having a structure in which a tubular wear-resistant element, which is a buffer part with which a workboat comes into contact, is attached via a lower support and an upper support. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 59-134210 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional boat landings, the connection parts between the tubular wear-resistant element and the lower and upper supports are provided at the same position as the tubular wear-resistant element, which is the buffer part, when viewed in the vertical direction. This makes the part that the work boat comes into contact with the boat landing prone to become uneven, and there is a risk of the work boat being damaged when it comes into contact with the boat landing.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a boat landing, a method for installing a boat landing, a method for replacing a boat landing, and an offshore structure that can reduce damage to workboats. [Means for solving the problem]

[0006] <1> The boat landing of aspect 1 of the present invention is a boat landing installed on an offshore structure that supports an offshore wind turbine, and is characterized in that it comprises a buffer section that contacts the ship and an insertion section that is inserted into a pipe section provided on the offshore structure, and the insertion section is closer to the center of the offshore structure than the buffer section when viewed in the vertical direction.

[0007] According to the invention of aspect 1, the insertion part to be inserted into the pipe part provided in the marine structure is closer to the center of the marine structure than the buffer part when viewed in the vertical direction. In other words, the connection part between the insertion part and the pipe part is located inside the boat landing than the buffer part. This makes it possible to prevent the part with which the work boat comes into contact from becoming uneven. Therefore, when the work boat comes into contact with the buffer part of the boat landing, it is possible to prevent the work boat from colliding with and damaging the connection part between the insertion part and the pipe part.

[0008] <2> A boat landing according to aspect 2 of the present invention is characterized in that, in the boat landing according to aspect 1, the insertion portion is an inverted L-shaped member having one end connected to the buffer portion, a horizontal portion extending along the horizontal direction, and a vertical portion extending downward from the other end of the horizontal portion, and the lower end of the vertical portion is inserted into the pipe portion.

[0009] According to the invention of aspect 2, the insertion part is an inverted L-shaped member including a horizontal part and a vertical part. The lower end of the vertical part is inserted into a pipe part provided in the marine structure. This allows the boat landing to be attached to the marine structure by inserting the insertion part into the pipe part. This makes it possible to eliminate the need for welding or grouting. This makes it easy to install and replace the boat landing.

[0010] <3> A boat landing according to aspect 3 of the present invention is characterized in that, in the boat landing according to aspect 2, it further comprises a ladder section, which is located between the buffer section and the vertical section when viewed along the horizontal direction.

[0011] According to the invention of the third aspect, the ladder section is located between the buffer section and the vertical section when viewed in the horizontal direction. This allows the ladder section to be located closer to the marine structure than the buffer section, for example. Therefore, when a work boat comes into contact with the buffer section, damage to the ladder section due to the collision of the work boat can be suppressed. In addition, for example, the ladder section can be positioned horizontally away from the vertical section, which can prevent the ladder section from interfering with the work of inserting the vertical section into the pipe section, thereby preventing the ladder section from affecting the installation and replacement of the boat landing.

[0012] <4> A boat landing according to a fourth aspect of the present invention is the boat landing according to any one of the first to third aspects, characterized in that the insertion portion is located below the sea surface.

[0013] According to the invention of the fourth aspect, the insertion part is located below the sea surface. This allows the boat landing to be attached to the marine structure in the sea by simply inserting the vertical part of the insertion part into the pipe part. This makes it possible to eliminate the need for, for example, welding or grouting work underwater. This allows the boat landing to be easily attached and replaced.

[0014] <5> A boat landing according to a fifth aspect of the present invention is the boat landing according to any one of the first to fourth aspects, further comprising a steel pipe portion connecting the buffer portion and the marine structure; The present invention further comprises a flange on an outer circumferential surface of the steel pipe portion, and the steel pipe portion is located above the insertion portion.

[0015] According to the invention of aspect 5, the structure further includes a steel pipe portion that connects the buffer portion and the marine structure. In addition to inserting the insertion portion into the pipe portion, the buffer portion and the marine structure are connected by the steel pipe portion, thereby making the connection between the buffer portion and the marine structure more reliable. In addition, when a steel pipe section is provided, if it becomes necessary to replace a boat landing installed on an offshore structure in service, the steel pipe section must be cut. Therefore, a flange is provided on the outer circumferential surface of the steel pipe section. This makes it possible to prevent deformation of the cut surface of the steel pipe section when the steel pipe section is cut. Therefore, when replacing the boat landing, the steel pipe section provided on the new boat landing and the steel pipe section remaining on the marine structure can be easily welded. Also, by cutting the steel pipe section when replacing the boat landing, it is possible to prevent the marine structure from being affected. Furthermore, the steel pipe portion is located above the insertion portion. This makes it easier to position the steel pipe portion above the sea level, for example. This prevents welding of the steel pipe portion from having to be done underwater, making the welding work easier to perform.

[0016] <6> A boat landing according to a sixth aspect of the present invention is the boat landing according to the fifth aspect, characterized in that a landing is provided above the steel pipe section.

[0017] For safety reasons, the ladder section needs to have landings at certain heights, but due to layout considerations, the landings need to be placed to avoid buffer areas. According to the invention of aspect 6, the landing is provided above the steel pipe section. This allows the landing to be provided directly above the buffer section while avoiding the landing from interfering with the buffer section. Furthermore, for example, by extending the support point of the landing from the steel pipe section, the structure of the marine structure can be simplified compared to a case where the landing and the marine structure are directly connected. This makes it easier to design the marine structure.

[0018] <7> The boat landing according to a seventh aspect of the present invention is the boat landing according to the sixth aspect, characterized in that a support member for supporting the landing is provided on the upper surface of the steel pipe section.

[0019] According to the invention of the seventh aspect, a support member for supporting the landing is provided on the upper surface of the steel pipe section, in other words, the landing provided on the steel pipe section is connected to the steel pipe section via the support member. This makes it possible to eliminate the need to consider the support member and the landing when performing a structural analysis of an offshore structure, for example. This makes it possible to facilitate the design of the offshore structure, for example.

[0020] <8> The boat landing of aspect 8 of the present invention is a boat landing of any one of aspects 1 to 7, characterized in that it includes an upper insertion portion and a lower insertion portion, and the upper insertion portion and the lower insertion portion are inserted into the pipe portion provided on the marine structure.

[0021] According to the invention of aspect 8, the boat landing includes an upper insertion section and a lower insertion section. This allows the buffer section to be supported by the multiple insertion sections. This allows the buffer section to have a structure that is more resistant to impact. This makes it possible to prevent the buffer section from being damaged by a collision with a work boat. Alternatively, the structure can be established even if the buffer section is relatively long.

[0022] <9> A boat landing according to a ninth aspect of the present invention is the boat landing according to the eighth aspect, characterized in that the upper insertion portion overlaps with the lower insertion portion when viewed along the vertical direction.

[0023] According to the invention of the ninth aspect, the upper insertion portion overlaps with the lower insertion portion when viewed in the vertical direction. This allows, for example, the components to be unified, which facilitates the management of production. Furthermore, when attaching the boat landing to the marine structure, the work of inserting the upper insertion portion and the lower insertion portion into the pipe portion can be easily performed.

[0024] <10> A boat landing of aspect 10 of the present invention is characterized in that, in the boat landing of aspect 8 or aspect 9, the marine structure is a jacket structure including a first leg, the upper insertion portion and the lower insertion portion are attached to the first leg, and a straight line connecting the upper insertion portion and the lower insertion portion is approximately parallel to the first leg.

[0025] According to the invention of the tenth aspect, the upper insertion part and the lower insertion part are attached to the first leg included in the jacket structure. Here, the first leg may be inclined with respect to the up-down direction, for example. In this case, if the upper insertion part and the lower insertion part are positioned so as to overlap when viewed along the vertical direction, it may be necessary to make the lower insertion part smaller in terms of layout. Therefore, the straight line connecting the upper insertion section and the lower insertion section is made approximately parallel to the first leg. This makes it possible to prevent the size of the lower insertion section from becoming smaller. In addition, for example, the aesthetic appearance of the boat landing can be improved.

[0026] <11> A boat landing according to aspect 11 of the present invention is a boat landing according to any one of aspects 8 to 10, wherein the marine structure is a jacket structure including a first leg, a second leg, and a brace connecting the first leg and the second leg, and the boat landing further includes a steel pipe section connecting the buffer section and the first leg, and the steel pipe section, the upper insertion section, and the lower insertion section are arranged between the upper end of the brace and the lower end of the brace.

[0027] According to the invention of aspect 11, the steel pipe section, the upper insertion section, and the lower insertion section are disposed between the upper end of the brace and the lower end of the brace. This makes it possible to prevent, for example, the connection section between the leg and the steel pipe section, the upper insertion section, and the lower insertion section from interfering with the connection section between the brace and the first leg. This makes it possible to prevent the structure of the marine structure from becoming complicated.

[0028] <12> A boat landing according to aspect 12 of the present invention is a boat landing according to any one of aspects 1 to 11, further comprising a first insertion section, a second insertion section, and a steel pipe section connecting the buffer section and the marine structure, wherein the buffer section includes two rod-shaped members, each of the two rod-shaped members extending along a vertical direction, one of the two rod-shaped members being connected to the first insertion section and the other being connected to the second insertion section, the first insertion section being inserted into a first pipe section provided in the marine structure, the second insertion section being inserted into a second pipe section provided in the marine structure, and the steel pipe section being connected to both of the two rod-shaped members.

[0029] According to the invention of aspect 12, one of the two rod-shaped members is connected to the first insertion portion, and the other is connected to the second insertion portion. In this manner, by providing separate insertion portions for supporting one and the other of the rod-shaped members, the rod-shaped members can be reliably supported. The first insertion portion is inserted into the first tubular portion, and the second insertion portion is inserted into the second tubular portion. This makes it easy to attach the boat landing to the marine structure.

[0030] Here, the steel pipe section ensures the connection strength between the buffer section and the marine structure. For this reason, a steel pipe section with a relatively large outer diameter is used. In this case, if a steel pipe section is provided separately for each of the two rod-shaped members of the buffer section, the two steel pipe sections may interfere with each other. Therefore, the steel pipe portion is connected to both of the two rod-shaped members. In other words, one steel pipe portion is provided for each of the two rod-shaped members. This makes it possible to prevent, for example, the above-mentioned problems from occurring.

[0031] <13> A boat landing according to aspect 13 of the present invention is a boat landing according to any one of aspects 1 to 12, characterized in that the marine structure is provided with an external work platform on which a davit crane can be mounted, and the buffer portion is farther from the center of the marine structure than the external work platform when viewed in the vertical direction.

[0032] According to the invention of aspect 13, the buffer part is farther from the center of the marine structure, as viewed in the vertical direction, than an external working floor on which a david crane provided on the marine structure can be mounted. This allows the buffer part of the boat landing to be located outside the external working floor, as viewed in the vertical direction, in the marine structure. This makes it possible to prevent the work boat from being positioned below the external working floor when it comes into contact with the boat landing. This makes it easier for the david crane provided on the external working floor to lift cargo loaded on a work boat that comes into contact with the boat landing.

[0033] <14> A boat landing installation method according to aspect 14 of the present invention is a method for installing a boat landing on an offshore structure, the boat landing comprising: a buffer section for contacting a ship; an insertion section for being inserted into a pipe section provided on an offshore structure supporting an offshore wind turbine, the insertion section being closer to the center of the offshore structure than the buffer section when viewed vertically; and a steel pipe section capable of connecting the buffer section to the offshore structure, the method comprising an insertion step for inserting the insertion section into the pipe section; and a welding step for welding the steel pipe section to the offshore structure after the insertion step.

[0034] According to the invention of aspect 14, there is provided an inserting step of inserting the insertion portion into the pipe portion, and a welding step of welding the steel pipe portion to the first leg after the inserting step. This allows the boat landing to be temporarily fixed in position relative to the marine structure by the inserting step, and then fixed to the marine structure by the welding step. This makes it possible to facilitate the operation of the welding step. This makes it possible to improve the workability of the welding step.

[0035] <15> A method for replacing a boat landing according to aspect 15 of the present invention is a method for replacing a boat landing attached to an offshore structure, the method comprising: a buffer section that comes into contact with a ship; an insertion section that is inserted into a pipe section provided on an offshore structure supporting an offshore wind turbine, the insertion section being closer to the center of the offshore structure than the buffer section when viewed in the vertical direction; and a steel pipe section that can connect the buffer section to the offshore structure, the method comprising: a cutting step for cutting the steel pipe section while leaving a remaining section on the offshore structure side; an extraction step for extracting the insertion section from the pipe section; a replacement insertion step for inserting the insertion section provided on a new boat landing into the pipe section; and a replacement welding step for welding the steel pipe section provided on the new boat landing to the remaining section.

[0036] According to the invention of aspect 15, in the cutting step, the steel pipe portion is cut while leaving the remainder on the marine structure side. This makes it possible to suppress the influence on the marine structure when the old boat landing is removed from the marine structure. In the replacement welding step, the steel pipe portion of the new boat landing is welded to the remainder. This makes it possible to suppress the influence on the marine structure when the new boat landing is attached to the marine structure.

[0037] <16> A marine structure according to a sixteenth aspect of the present invention is characterized in that it is provided with a boat landing according to any one of aspects 1 to thirteen.

[0038] According to the invention of the sixteenth aspect, an offshore structure is provided with the boat landing of the present invention. This allows the offshore structure to enjoy the above-mentioned effects. That is, for example, it is possible to prevent a work boat from colliding with and damaging the connection between the boat landing and the offshore structure. Effect of the Invention

[0039] According to the present invention, it is possible to provide a boat landing, a boat landing installation method, a boat landing replacement method, and an offshore structure that can prevent damage to a work boat. [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is a perspective view of an offshore structure according to a first embodiment. [Diagram 2] FIG. 1 is a perspective view of a boat landing according to a first embodiment. [Diagram 3] FIG. 1 is a plan view of the marine structure according to the first embodiment. [Figure 4] FIG. 1 is a front view of a boat landing according to a first embodiment. [Diagram 5] FIG. 2 is a side view of the boat landing according to the first embodiment. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI shown in FIG. 5. [Figure 7] 7 is a cross-sectional view taken along the line VII-VII shown in FIG. 5. [Figure 8] 8 is a view taken in the direction of the arrow VIII shown in FIG. 7. [Figure 9] FIG. 11 is a perspective view of the marine structure according to the second embodiment. [Figure 10] FIG. 11 is a side view of the boat landing according to the second embodiment. [Figure 11] 11 is a cross-sectional view taken along the line XI-XI shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] (First embodiment) Hereinafter, a boat landing 100 according to an embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view of an offshore structure 200 according to a first embodiment. That is, it is a diagram showing an example in which a boat landing 100 is provided on the offshore structure 200, which is a jacket structure. 1, the boat landing 100 according to this embodiment is installed on an offshore structure 200 that supports an offshore wind turbine W. In this embodiment, the offshore structure 200 is provided with an external work platform OF on which a david crane DC can be mounted. The david crane DC is used, for example, to hoist materials transported by a work boat up to the external work platform OF.

[0042] 1, the marine structure 200 is, for example, a jacket structure. That is, in this embodiment, the marine structure 200 includes a transition piece 200A, a leg 200B, and a brace 200E. The transition piece 200A is provided on the upper part of the offshore structure 200. The lower end of the offshore wind turbine tower T is connected to the transition piece 200A. The transition piece 200A is composed of, for example, an upper flange 200A1, a lower flange 200A2, a web 200A3 that connects the upper flange 200A1 and the lower flange 200A2, and a wind turbine tower connection part 200A4 supported by the above-mentioned components.

[0043] In this embodiment, the external working floor OF is provided, for example, on the transition piece 200A. In this case, the external working floor OF is connected, for example, to a portion of the leg 200B that is located between the upper flange 200A1 and the lower flange 200A2, and is supported by a support column P that protrudes outward from the transition piece 200A. Alternatively, without being limited to this, the position of the support column P may be appropriately determined depending on the positional relationship between the boat landing 100 and the external working floor OF, or the positional relationship between the offshore wind turbine W and the external working floor OF.

[0044] An upper portion of the leg 200B is connected to the transition piece 200A. A lower portion of the leg 200B is connected to a pile (not shown) driven into the seabed. In this way, the leg 200B supports the transition piece 200A on the ocean. For example, four legs 200B are provided on the marine structure 200. In the following description, one of the four legs 200B is referred to as a first leg 200C. Of the four legs 200B, the leg 200B located next to the first leg 200C is referred to as a second leg 200D.

[0045] The brace 200E connects adjacent legs 200B in the marine structure 200. That is, the brace 200E connects, for example, the first leg 200C and the second leg 200D. The brace 200E is disposed, for example, in an X-shape between the legs 200B. In this way, the brace 200E reinforces the marine structure 200.

[0046] FIG. 2 is a perspective view of the boat landing 100 provided on the offshore structure 200. Fig. 3 is a plan view of the marine structure 200 according to the first embodiment. Fig. 3 particularly shows the positional relationship between the marine structure 200 and the boat landing 100 as viewed along the vertical direction. FIG. 4 is a front view of the boat landing 100. FIG. 5 is a side view of the boat landing 100. FIG. 6 is a cross-sectional view taken along the line VI-VI shown in FIG. FIG. 7 is a cross-sectional view taken along the line VII-VII shown in FIG. FIG. 8 is a view taken in the direction of an arrow VIII shown in FIG. The boat landing 100 is used to bring a work boat into contact with the marine structure 200. That is, the boat landing 100 is used to stabilize the position of the work boat by bringing the work boat into contact with the marine structure 200, for example, when a worker moves from the work boat to the marine structure 200, or when materials loaded on the work boat are lifted by a davit crane DC. As shown in FIG. 2, the boat landing 100 includes a buffer section 10, an insertion section 20, a ladder section 30, and a steel pipe section 40.

[0047] The buffer section 10 is a portion of the boat landing 100 that comes into contact with a boat. As shown in Fig. 2, the buffer section 10 includes two rod-shaped members 11. Each of the two rod-shaped members 11 extends along the vertical direction. 3, the buffer section 10 is provided at a position farther from the center of the marine structure 200 than the external work platform OF when viewed in the vertical direction. In other words, in the marine structure 200, the buffer section 10 of the boat landing 100 is provided outside the external work platform OF when viewed in the vertical direction. This makes it easier for the davit crane DC provided on the external work platform OF to lift cargo loaded on a work vessel that comes into contact with the boat landing 100.

[0048] The insertion part 20 is used to connect the buffer part 10 to the marine structure 200. Specifically, the insertion part 20 connects the rod-shaped member 11 to the marine structure 200 by being inserted into the inside of a pipe part 210 provided in the marine structure 200. The insertion part 20 is located below the sea surface. That is, the connection between the buffer part 10 and the marine structure 200 by inserting the insertion part 20 into the pipe part 210 is performed underwater. This makes it unnecessary to perform work such as welding or grouting underwater.

[0049] 5, the insertion section 20 includes a horizontal section 21 and a vertical section 22. The horizontal section 21 and the vertical section 22 form the insertion section 20 in an inverted L shape. More specifically, this is as follows. The horizontal portion 21 is a portion of the insertion portion 20, one end of which is connected to the rod-shaped member 11 of the buffer unit 10 and extends along the horizontal direction. The horizontal portion 21 and the rod-shaped member 11 of the buffer unit 10 are connected by, for example, welding. The vertical portion 22 is a portion of the insertion portion 20 that extends downward from the other end of the horizontal portion 21. The lower end of the vertical portion 22 is inserted into the inside of the pipe portion 210. In this embodiment, the insertion portion 20 being inserted into the pipe portion 210 means that the lower end of the vertical portion 22 is inserted into the pipe portion 210. The horizontal portion 21 and the vertical portion 22 are connected by, for example, welding. Alternatively, the horizontal portion 21 and the vertical portion 22 may be formed by bending a single linear member.

[0050] 7, the insertion section 20 is provided at a position closer to the center of the marine structure 200 than the buffer section 10 when viewed in the vertical direction. This prevents a work boat that comes into contact with the buffer section 10 from interfering with the insertion section 20. 7, the insertion section 20 includes a first insertion section 20A and a second insertion section 20B. The first insertion section 20A and the second insertion section 20B have the same configuration.

[0051] One of the two rod-shaped members 11 is connected to the first insertion portion 20A, and the other is connected to the second insertion portion 20B. The first insertion portion 20A is inserted into a first pipe portion 211 provided in the marine structure 200. The second insertion portion 20B is inserted into a second pipe portion 212 provided in the marine structure 200. In this way, the two rod-shaped members 11 included in the buffer portion 10 are each connected to the marine structure 200.

[0052] 2 and 5, the insertion portion 20 is provided at least in two positions, upper and lower, for one rod-shaped member 11. Hereinafter, of the insertion portions 20 provided at two positions, upper and lower, the one located at the upper side will be referred to as an upper insertion portion 20u, and the one located at the lower side will be referred to as a lower insertion portion 20l. For example, the upper insertion portion 20u which is the first insertion portion 20A is referred to as a first upper insertion portion 20Au, and the lower insertion portion 20l which is the first insertion portion 20A is referred to as a first lower insertion portion 20Al. Similarly, the upper insertion portion 20u which is the second insertion portion 20B is referred to as a second upper insertion portion 20Bu, and the lower insertion portion 20l which is the second insertion portion 20B is referred to as a second lower insertion portion 20Bl. The first upper insertion portion 20Au and the second upper insertion portion 20Bu have the same configuration, and the first lower insertion portion 20Al and the second lower insertion portion 20Bl have the same configuration. Hereinafter, when there is no need to distinguish between the first upper insertion portion 20Au and the second upper insertion portion 20Bu, they will be referred to as the upper insertion portion 20u. When there is no need to distinguish between the first lower insertion portion 20Al and the second lower insertion portion 20Bl, they will be referred to as the lower insertion portion 20l.

[0053] Corresponding to the fact that the insertion sections 20 are provided at two positions, upper and lower, on one rod-shaped member 11, the tube sections 210 are also provided at two positions, upper and lower. Hereinafter, of the tube sections 210 provided at two positions, upper and lower, the one located at the upper side will be referred to as upper tube section 210u, and the one located at the lower side will be referred to as lower tube section 210l. For example, the upper pipe section 210u which is the first pipe section 211 is referred to as a first upper pipe section 211u, and the lower pipe section 210l which is the first pipe section 211 is referred to as a first lower pipe section 211l. Similarly, the upper pipe portion 210u which is the second pipe portion 212 is referred to as a second upper pipe portion 212u, and the lower pipe portion 210l which is the second pipe portion 212 is referred to as a second lower pipe portion 212l. The first upper pipe portion 211u and the second upper pipe portion 212u have a similar configuration, and the first lower pipe portion 211l and the second lower pipe portion 212l have a similar configuration. Hereinafter, when there is no need to distinguish between the first upper pipe portion 211u and the second upper pipe portion 212u, they will be referred to as the upper pipe portion 210u.When there is no need to distinguish between the first lower pipe portion 211l and the second lower pipe portion 212l, they will be referred to as the lower pipe portion 210l.

[0054] The upper insertion portion 20u and the lower insertion portion 20l are inserted into the upper tube portion 210u and the lower tube portion 210l, respectively. That is, the first upper insertion portion 20Au is inserted into the first upper pipe portion 211u, and the first lower insertion portion 20Al is inserted into the first lower pipe portion 211l. Moreover, the second upper insertion section 20Bu is inserted into the second upper pipe section 212u, and the second lower insertion section 20Bl is inserted into the second lower pipe section 212l.

[0055] 5, the upper insertion section 20u and the lower insertion section 20l are attached to the first leg 200C via the upper tube section 210u and the lower tube section 210l, respectively. At this time, the straight line connecting the upper insertion section 20u and the lower insertion section 20l is approximately parallel to the first leg 200C. 8, in the first insertion section 20A, a straight line PL connecting an intersection P1 between the central axis of the horizontal section 21 and the central axis of the vertical section 22 of the first upper insertion section 20Au and an intersection P2 between the central axis of the horizontal section 21 and the central axis of the vertical section 22 of the first lower insertion section 20Al is substantially parallel to the central axis of the first leg 200C. The same is true in the second insertion section 20B. In this embodiment, "substantially parallel" means that the crossing angle between the two straight lines is 10° or less.

[0056] The steel pipe section 40 connects the buffer section 10 and the marine structure 200. That is, as shown in FIG. 5, the steel pipe section 40 connects the buffer section 10 and the first leg 200C. The steel pipe section 40 is located above the insertion section 20. The steel pipe section 40 is connected to the buffer section 10 and the first leg 200C, for example, by welding. This allows the steel pipe section 40 to connect the buffer section 10 and the marine structure 200. In addition, it is more preferable that the steel pipe section 40 is located above the sea surface in order to make it easier to weld the steel pipe section 40 when the boat landing 100 is damaged and needs to be replaced at sea.

[0057] Here, as described above, the insertion section 20 is located below the sea surface. Moreover, the insertion section 20 is inserted into the pipe section 210 provided in the marine structure 200, and no welding or grouting is performed. In contrast, the steel pipe section 40 is connected to the buffer section 10 and the marine structure 200 by welding. In this way, the steel pipe section 40 more securely fixes the buffer section 10 to the marine structure 200. In other words, the steel pipe section 40 ensures the connection strength between the buffer section 10 and the marine structure 200.

[0058] The steel pipe section 40 has a relatively large outer diameter in order to secure the connection strength between the buffer section 10 and the marine structure 200. In this case, for example, if the steel pipe section 40 is provided on each of the two rod-shaped members 11 of the buffer section 10, the two steel pipe sections 40 may interfere with each other. To prevent this, the steel pipe section 40 is connected to both of the two rod-shaped members 11 included in the buffer section 10. In other words, one steel pipe section 40 is provided on each of the two rod-shaped members 11. Specifically, as shown in FIG. 6, the steel pipe section 40 has a branched shape between the first leg 200C and the buffer section 10. This keeps the connection between the marine structure 200 and the steel pipe section 40 at one location, and prevents the multiple steel pipe sections 40 from interfering with each other.

[0059] As shown in Figures 5 and 6, a flange 41 is provided on the outer circumferential surface of the steel pipe section 40. The flange 41 is provided at a location closer to the center of the marine structure 200, which is the jacket structure, than the insertion section 20. The flange 41 is an annular member. The inner circumferential surface of the flange 41 is disposed so as to contact the outer circumferential surface of the steel pipe section 40. The inner circumferential surface of the flange 41 and the outer circumferential surface of the steel pipe section 40 are connected, for example, by welding. The flange 41 is provided to prevent deformation of the cut surface of the steel pipe section 40 when the steel pipe section 40 is cut for replacement of the boat landing 100 (described later).

[0060] As described above, in this embodiment, the marine structure 200 is a jacket structure. The marine structure 200, which is a jacket structure, includes a first leg 200C and a brace 200E that connects the first leg 200C and the second leg 200D. In this embodiment, the steel pipe section 40, the upper insertion section 20u, and the lower insertion section 20l are disposed between the upper end of the brace 200E and the lower end of the brace 200E, as shown in Fig. 1. That is, the steel pipe section 40, the upper insertion section 20u, and the lower insertion section 20l are provided to avoid the connection section between the first leg 200C and the brace 200E. This prevents the structure of the marine structure 200 from becoming complicated.

[0061] The ladder section 30 is used for a worker to move from a work boat that has come into contact with the buffer section 10 toward the external work platform OF. As shown in FIG. 8, the ladder section 30 is located between the buffer section 10 and the vertical section 22 when viewed in the horizontal direction. In other words, in the marine structure 200, the ladder section 30 is located outside the vertical section 22. This prevents the ladder section 30 from interfering when the vertical section 22 is inserted into the pipe section 210. The buffer section 10 is located outside the ladder section 30 in the boat landing 100. This prevents the work boat from colliding with the ladder section 30.

[0062] Here, for safety reasons, the ladder section 30 needs to have landings 31 at certain heights. At this time, in terms of layout, the landings 31 need to be provided so as to avoid the buffer section 10. In this embodiment, the landings 31 are provided on the steel pipe section 40 as shown in FIG. 5. Specifically, a support member 31p for supporting the landing 31 is provided on the upper surface of the steel pipe section 40. The landing 31 is connected to the steel pipe section 40 via the support member 31p. This allows the landing 31 to be provided directly above the buffer section 10 while avoiding interference between the landing 31 and the buffer section 10. Note that the support member 31p is preferably provided so as not to interfere with the leg 200B of the jacket structure.

[0063] (How to install Boat Landing 100) Next, a method for installing the boat landing 100 according to this embodiment on the marine structure 200 will be described. The method for installing the boat landing 100 includes an insertion step and a welding step. This step is carried out, for example, in a factory for manufacturing the marine structure 200 before the marine structure 200 is installed on the sea.

[0064] The insertion step is a process of inserting the insertion parts 20 of the boat landing 100 into the pipe parts 210 provided in the marine structure 200. In the insertion step, for example, as described above, each of the multiple insertion parts 20 of the boat landing 100 is aligned and inserted into each of the multiple pipe parts 210 provided in the marine structure 200. In this way, the boat landing 100 is temporarily fixed to the marine structure 200. The welding step is a process of welding the steel pipe section 40 of the boat landing 100 to the marine structure 200 after the insertion step. In this way, the boat landing 100 is fixed to the marine structure 200. Through each of the above steps, the boat landing 100 is installed on the marine structure 200.

[0065] (How to replace Boat Landing 100) Next, a method for replacing the boat landing 100 according to this embodiment attached to the marine structure 200 in service will be described. The method for replacing the boat landing 100 includes a cutting step, a removal step, a replacement insertion step, a groove forming step, and a replacement welding step. This process is performed, for example, when it becomes necessary to replace the boat landing 100 due to damage or the like in the marine structure 200 in service at sea.

[0066] The cutting step is a process of cutting the steel pipe section 40. In the cutting step, the steel pipe section 40 is cut while leaving a remaining section 42 on the marine structure 200 side. The remaining section 42 is a portion of the steel pipe section 40 including the connection section with the first leg 200C and the flange 41, as shown in FIG. 5. The remaining section 42 is, for example, a portion located on the marine structure 200 side of the boundary line B shown in FIG. 5. In other words, in the cutting step, the steel pipe section 40 is cut while leaving the flange 41 on the marine structure 200 side. This prevents the cut surface of the remaining section 42 in the steel pipe section 40 from being deformed.

[0067] The removal step is a process of removing the insertion portion 20 from the pipe portion 210. By cutting the steel pipe portion 40 in the cutting step, the boat landing 100 is released from its fixation to the marine structure 200. Therefore, in the removal step, the boat landing 100 can be pulled upward to remove the insertion portion 20 from the pipe portion 210. In the removal step, the boat landing 100 is pulled upward, for example, by a crane (not shown) of a crane ship used in the replacement work of the boat landing 100. In this way, the old boat landing 100 to be replaced is removed from the marine structure 200.

[0068] The replacement insertion step is a process of inserting the insertion section 20 of the new boat landing 100 into the pipe section 210. In the replacement insertion step, as described above, each of the multiple insertion sections 20 of the boat landing 100 is aligned and inserted into each of the multiple pipe sections 210 provided in the marine structure 200. In this way, the boat landing 100 is temporarily fixed to the marine structure 200.

[0069] The groove forming step is a process of forming a groove by smoothing the cut surface of the remaining portion 42 generated by the cutting step. In the groove forming step, the shape of the remaining portion 42 is smoothed by grinding the cut surface of the remaining portion 42 using, for example, a grinder or the like. This makes it easier to weld the remaining portion 42 and the steel pipe portion 40 in the exchange welding step.

[0070] The replacement welding step is a process of welding the steel pipe section 40 of the new boat landing 100 to the remaining section 42 generated by the cutting step. By welding the new steel pipe section 40 to the remaining section 42 provided on the marine structure 200 side in this manner, the influence of welding on the marine structure 200 is suppressed compared to the case where the steel pipe section 40 is directly welded to the marine structure 200. Through the above steps, the boat landing 100 is replaced.

[0071] As described above, according to the boat landing 100 of this embodiment, the insertion section 20 inserted into the pipe section 210 provided in the marine structure 200 is closer to the center of the marine structure 200 than the buffer section 10 when viewed along the vertical direction. In other words, the connection section between the insertion section 20 and the pipe section 210 is located on the inside of the boat landing 100 than the buffer section 10. This makes it possible to prevent the portion with which the work boat comes into contact from becoming uneven. Therefore, when the work boat comes into contact with the buffer section 10 of the boat landing 100, it is possible to prevent the work boat from colliding with and damaging the connection section between the insertion section 20 and the pipe section 210.

[0072] Moreover, the insertion part 20 is an inverted L-shaped member including a horizontal part 21 and a vertical part 22. The lower end of the vertical part 22 is inserted into a pipe part 210 provided in the marine structure 200. This allows the boat landing 100 to be attached to the marine structure 200 by inserting the insertion part 20 into the pipe part 210. This makes it possible to eliminate the need for welding or grouting. This allows the boat landing 100 to be easily attached and replaced.

[0073] Moreover, the ladder section 30 is located between the buffer section 10 and the vertical section 22 when viewed in the horizontal direction. This allows, for example, the ladder section 30 to be disposed closer to the marine structure 200 than the buffer section 10. Therefore, when a work boat comes into contact with the buffer section 10, damage to the ladder section 30 due to the collision of the work boat can be suppressed. Also, for example, the ladder section 30 can be disposed at a position horizontally separated from the vertical section 22. This makes it possible to prevent the ladder section 30 from interfering with the work of inserting the vertical section 22 into the pipe section 210. This makes it possible to prevent the ladder section 30 from affecting the installation and replacement of the boat landing 100.

[0074] In addition, the insertion part 20 is located below the sea surface. This allows the boat landing 100 to be attached to the marine structure 200 in the sea simply by inserting the vertical part 22 of the insertion part 20 into the pipe part 210. This makes it possible to eliminate the need for, for example, welding or grouting work underwater. This allows the boat landing 100 to be easily attached and replaced.

[0075] The structure further includes a steel pipe section 40 that connects the buffer section 10 and the marine structure 200. In addition to inserting the insertion section 20 into the pipe section 210, connecting the buffer section 10 and the marine structure 200 with the steel pipe section 40 can make the connection between the buffer section 10 and the marine structure 200 more reliable. In addition, when the steel pipe section 40 is provided, if it becomes necessary to replace the boat landing 100 installed on the marine structure 200 in service, the steel pipe section 40 must be cut. Therefore, a flange 41 is provided on the outer peripheral surface of the steel pipe section 40. This makes it possible to prevent deformation of the cut surface of the steel pipe section 40 when the steel pipe section 40 is cut. Therefore, when replacing the boat landing 100, the steel pipe section 40 provided on the new boat landing 100 and the steel pipe section 40 remaining on the marine structure 200 can be easily welded together. Furthermore, by cutting the steel pipe section 40 when replacing the boat landing 100, it is possible to prevent any effect on the marine structure 200. Furthermore, the steel pipe section 40 is located above the insertion section 20. This makes it easier to dispose the steel pipe section 40 above the sea surface, for example. This prevents the welding work of the steel pipe section 40 from being performed underwater, making it easier to perform the welding work.

[0076] For safety reasons, it is necessary to provide landings 31 at certain height intervals in the ladder section 30. However, in terms of layout, it is necessary to provide the landings 31 so as to avoid the buffer section 10. Therefore, the landing 31 is provided above the steel pipe section 40. This allows the landing 31 to be provided directly above the buffer section 10 while avoiding the landing 31 from interfering with the buffer section 10. Furthermore, for example, by extending the support point of the landing 31 from the steel pipe section 40, the structure of the marine structure 200 can be simplified compared to a case where the landing 31 and the marine structure 200 are directly connected. This makes it easier to design the marine structure 200.

[0077] Furthermore, a support member 31p that supports the landing 31 is provided on the upper surface of the steel pipe section 40. In other words, the landing 31 provided on the steel pipe section 40 is connected to the steel pipe section 40 via the support member 31p. This makes it possible to eliminate the need to take into account the support member 31p and the landing 31, for example, when performing a structural analysis of the marine structure 200. This makes it possible to facilitate the design of the marine structure 200, for example.

[0078] The boat landing 100 also includes an upper insertion section 20u and a lower insertion section 20l. This allows the buffer section 10 to be supported by the multiple insertion sections 20. This allows the buffer section 10 to have a structure that is more resistant to impact. This makes it possible to prevent the buffer section 10 from being damaged by a collision with a work boat. Alternatively, even if the buffer section 10 is relatively long, the structure can be established.

[0079] The upper insertion portion 20u and the lower insertion portion 20l are attached to a first leg 200C included in the jacket structure. Here, the first leg 200C may be inclined with respect to the up-down direction, for example. In this case, if the upper insertion portion 20u and the lower insertion portion 20l are positioned so as to overlap with each other when viewed in the vertical direction, it may be necessary to make the lower insertion portion 20l smaller in terms of layout. Therefore, the straight line connecting the upper insertion portion 20u and the lower insertion portion 20l is made substantially parallel to the first leg 200C. This makes it possible to prevent the size of the lower insertion portion 20l from becoming small. In addition, for example, the aesthetic appearance of the boat landing 100 can be improved.

[0080] Moreover, the steel pipe section 40, the upper insertion section 20u, and the lower insertion section 20l are disposed between the upper end of the brace 200E and the lower end of the brace 200E. This makes it possible to prevent, for example, the connection section between the leg 200B and the steel pipe section 40, the upper insertion section 20u, and the lower insertion section 20l from interfering with the connection section between the brace 200E and the first leg 200C. This makes it possible to prevent the structure of the marine structure 200 from becoming complicated.

[0081] Moreover, one of the two rod-shaped members 11 is connected to the first insertion portion 20A, and the other is connected to the second insertion portion 20B. In this manner, by providing the insertion portions 20 that support one and the other of the rod-shaped members 11 individually, the rod-shaped members 11 can be reliably supported. The first insertion portion 20A is inserted into the first pipe portion 211, and the second insertion portion 20B is inserted into the second pipe portion 212. This makes it easy to attach the boat landing 100 to the marine structure 200.

[0082] Here, the steel pipe section 40 ensures the connection strength between the buffer section 10 and the marine structure 200. For this reason, a steel pipe section 40 with a relatively large outer diameter is used. In this case, if the steel pipe section 40 is provided individually on each of the two rod-shaped members 11 of the buffer section 10, the two steel pipe sections 40 may interfere with each other. Therefore, the steel pipe portion 40 is connected to both of the two rod-shaped members 11. In other words, one steel pipe portion 40 is provided for each of the two rod-shaped members 11. This makes it possible to prevent, for example, the above-mentioned problems from occurring.

[0083] Moreover, the buffer section 10 is farther from the center of the marine structure 200, as viewed in the vertical direction, than the external work floor OF on which the david crane DC provided on the marine structure 200 can be mounted. This allows the buffer section 10 of the boat landing 100 in the marine structure 200 to be disposed outside the external work floor OF, as viewed in the vertical direction. This makes it possible to prevent the work boat from being positioned below the external work floor OF when the work boat comes into contact with the boat landing 100. This makes it possible to easily lift cargo loaded on a work boat that comes into contact with the boat landing 100, by the david crane DC provided on the external work floor OF.

[0084] The method also includes an insertion step of inserting the insertion portion 20 into the pipe portion 210, and a welding step of welding the steel pipe portion 40 to the first leg 200C after the insertion step. This allows the boat landing 100 to be temporarily fixed in position relative to the marine structure 200 by the insertion step, and then the boat landing 100 to be fixed to the marine structure 200 by the welding step. This makes it possible to facilitate the work of the welding step. This makes it possible to improve the workability of the welding step.

[0085] Furthermore, in the cutting step, the steel pipe section 40 is cut, leaving the remaining section 42 on the marine structure 200 side. This makes it possible to suppress any influence on the marine structure 200 when removing the old boat landing 100 from the marine structure 200. In the replacement welding step, the steel pipe section 40 of the new boat landing 100 is welded to the remaining section 42. This makes it possible to suppress any influence on the marine structure 200 when attaching the new boat landing 100 to the marine structure 200.

[0086] Moreover, the marine structure 200 is equipped with the boat landing 100 according to the present invention. This allows the marine structure 200 to enjoy the above-mentioned effects. That is, for example, it is possible to prevent a work boat from colliding with and damaging the connection between the boat landing 100 and the marine structure 200.

[0087] Second embodiment Next, a boat landing 100 according to a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted, with only the differences being described. 9 is a perspective view of the marine structure 200 according to the second embodiment. That is, it is a diagram showing an example in which the boat landing 100 is provided on the marine structure 200 which is a monopile structure. FIG. 10 is a side view of the boat landing according to the second embodiment. FIG. 11 is a cross-sectional view taken along the line XI-XI shown in FIG. The second embodiment differs from the first embodiment in that the marine structure 200 is a monopile structure. That is, in the second embodiment, the boat landing 100 is provided on the monopile structure.

[0088] As shown in Figures 9 and 10, in the second embodiment, the steel pipe portion 40 is provided in a transition piece 200A of a monopile structure. As shown in Figure 11, in the second embodiment, the upper insertion portion 20u overlaps with the lower insertion portion 20l when viewed along the vertical direction. In the above respects, the boat landing 100 according to the second embodiment differs from the boat landing 100 according to the first embodiment.

[0089] As described above, in the boat landing 100 according to the second embodiment, the upper insertion section 20u overlaps with the lower insertion section 20l when viewed in the vertical direction. This allows, for example, the use of unified components, making it easier to manage production. Furthermore, when attaching the boat landing 100 to the marine structure 200, it is easier to insert the upper insertion section 20u and the lower insertion section 20l into the pipe section 210.

[0090] The technical scope of the present invention is not limited to the embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-mentioned method for installing the boat landing 100, the inserting step has been described as inserting the insertion part 20 into the pipe part 210 provided in the marine structure 200, but is not limited thereto. That is, first, before attaching the pipe part 210 to the marine structure 200, the insertion part 20 may be inserted into the pipe part 210 in advance, and the pipe part 210 may be attached to the marine structure 200 with the insertion part 20 inserted. In addition, in the embodiment, after the insertion step, the steel pipe section 40 of the boat landing 100 is welded to the marine structure 200 in the welding step, but this is not limited to this. That is, the steel pipe section 40 of the boat landing 100 and the marine structure 200 may be joined by, for example, bolts.

[0091] In addition, within the scope of the invention, the components in the embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0092] 10 Buffer section 11 Rod-shaped member 20 Insertion section 20A First Insertion Part 20Al 1st lower insert 20Au 1st upper insert 20B Second Insertion Part 20Bl 2nd lower insertion part 20Bu 2nd upper insert 20l lower insertion part 20u Upper Insertion Part 21 Horizontal part 22 Vertical section 30 Ladder section 31 Landing 31p Support member 40 Steel pipe section 41 Flange 42 Remainder 100 Boat Landing 200 Marine structures 200A Transition Piece 200A1 Top flange 200A2 Lower flange 200A3 Web 200A4 Wind turbine tower connection 200B Leg 200C 1st Leg 200D 2nd Leg 200E Brace 210 Pipe section 210l lower pipe section 210u upper pipe section 211 First Pipe 211l 1st lower pipe section 211u 1st upper pipe section 212 Second Pipe Section 212l 2nd lower pipe section 212u 2nd upper pipe section DC David Crane OF External work platform P-post

Claims

1. A boat landing installed on an offshore structure supporting an offshore wind turbine, a buffer portion in contact with the vessel; An insertion portion to be inserted into a pipe portion provided on the marine structure; Equipped with The insertion portion is closer to the center of the marine structure than the buffer portion when viewed along the vertical direction. A boat landing characterized by

2. The insertion portion is a horizontal portion having one end connected to the buffer portion and extending along a horizontal direction; a vertical portion extending downward from the other end of the horizontal portion; An inverted L-shaped member including: The lower end of the vertical portion is inserted into the pipe portion.

2. The boat landing of claim 1.

3. ladder section, Further comprising: The ladder portion is located between the buffer portion and the vertical portion when viewed along the horizontal direction.

3. The boat landing of claim 2.

4. The insert is located below sea level.

3. A boat landing according to claim 1 or 2.

5. A steel pipe portion connecting the buffer portion and the marine structure; Further comprising: A flange is provided on the outer circumferential surface of the steel pipe portion, The steel pipe portion is located above the insertion portion.

5. The boat landing of claim 4.

6. A landing is provided on the steel pipe section.

6. The boat landing of claim 5.

7. A support member for supporting the landing is provided on the upper surface of the steel pipe portion.

7. The boat landing of claim 6.

8. An upper insertion portion and a lower insertion portion, The upper insertion portion and the lower insertion portion are inserted into the pipe portion provided on the marine structure.

3. A boat landing according to claim 1 or 2.

9. The upper insertion portion overlaps with the lower insertion portion when viewed in the vertical direction.

9. The boat landing of claim 8.

10. the marine structure is a jacket structure including a first leg, the upper insert and the lower insert are attached to the first leg; A straight line connecting the upper insertion portion and the lower insertion portion is substantially parallel to the first leg.

9. The boat landing of claim 8.

11. The marine structure is a jacket structure including a first leg, a second leg, and a brace connecting the first leg and the second leg, The boat landing further includes a steel pipe portion connecting the buffer portion and the first leg, The steel pipe portion, the upper insertion portion, and the lower insertion portion are disposed between an upper end of the brace and a lower end of the brace.

9. The boat landing of claim 8.

12. A first insertion portion; A second insertion portion; A steel pipe portion connecting the buffer portion and the marine structure; Further comprising: The buffer portion includes two rod-shaped members, Each of the two rod-shaped members extends along a vertical direction, One of the two rod-shaped members is connected to the first insertion portion, and the other is connected to the second insertion portion, The first insertion portion is inserted into a first pipe portion provided in the marine structure, The second insertion portion is inserted into a second pipe portion provided in the marine structure, The steel pipe portion is connected to both of the two rod-shaped members.

3. A boat landing according to claim 1 or 2.

13. The marine structure is provided with an external work platform on which a davit crane can be mounted, The buffer portion is farther from the center of the marine structure than the external working floor when viewed in the vertical direction.

3. A boat landing according to claim 1 or 2.

14. a buffer portion in contact with the vessel; an insertion part that is inserted into a pipe part provided in an offshore structure supporting an offshore wind turbine, the insertion part being closer to a center of the offshore structure than the buffer part when viewed along a vertical direction; A steel pipe portion capable of connecting the buffer portion and the marine structure; A method for installing a boat landing comprising the steps of: an insertion step of inserting the insertion portion into the pipe portion; After the inserting step, a welding step of welding the steel pipe section to the marine structure; A method for installing a boat landing comprising the steps of:

15. a buffer portion in contact with the vessel; an insertion part that is inserted into a pipe part provided in an offshore structure supporting an offshore wind turbine, the insertion part being closer to a center of the offshore structure than the buffer part when viewed along a vertical direction; A steel pipe portion capable of connecting the buffer portion and the marine structure; Equipped with Boat landings attached to marine structures, A method of exchanging A cutting step of cutting the steel pipe portion while leaving a remainder on the marine structure side; a removal step of removing the insertion portion from the pipe portion; a replacement insertion step of inserting the insertion portion of a new boat landing into the pipe portion; A replacement welding step of welding the steel pipe portion provided with the new boat landing to the remaining portion; A method for replacing a boat landing, comprising:

16. A boat landing according to claim 1 or 2, 1. An offshore structure comprising:

Images