Floating Structures

Abstract

According to an embodiment of the invention, there is provided a floating structure comprising an open upper end, an open lower end opposite the open upper end, an annular wall extending between the open upper end and the open lower end, and a cylindrical structure arranged off-center of the floating structure and configured to support a tower. The annular wall forms a periphery of the floating structure to provide a central moonpool. At least a portion of the cylindrical structure extends along and is coupled to the annular wall. According to a further embodiment, there is also provided an apparatus including the floating structure and a tower supported by the cylindrical structure of the floating structure.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to Singapore Patent Application No. 10202104059Q, filed on April 21, 2021, the contents of which are incorporated herein by reference in their entirety for all purposes.

[0002] Various embodiments relate to floating structures, and more particularly to floating structures for facilitating support of a tower, and to an apparatus including such a floating structure and a tower supported by the floating structure. [Background technology]

[0003] The market for offshore wind power has expanded significantly and is still growing as wind harvesting remains one of the cleanest and most sustainable ways to generate electricity. Wind power harvesting is moving to deeper waters where the wind resources are better and more abundant compared to onshore or coastal. To do so, floating offshore wind turbines (FOWTs) are needed as it becomes extremely difficult or even impossible to install fixed or piled offshore wind turbines in deeper waters.

[0004] Several concepts for FOWT have been proposed.

[0005] For example, prior art CN212022920(U) describes a wave-foundation offshore wind turbine that includes a tower mast centrally received by a floating cabin below the water surface. Other publications, such as US2020300224(A1) and CN112177859(A), describe towers disposed on the upper deck of the respective floating platforms.

[0006] Yet another publication discloses a floating structure having a plurality of floating bodies hinged to adjacent connecting parts to adjustably form a ring shape, the floating structure further comprising a plurality of tensioning parts arranged to generate a tensioning force toward the inside of the ring shape on the floating bodies and the connecting parts. Another publication describes a circular barge having a bay that curves inwardly opposite the curved part of the barge for arranging a sustainable energy capture device. Another publication discloses a floating underwater support structure including a joint capable of rotational and angular movement along two or three axes, in which a buoyant member is connected to a truss having one or more elongated rigid members disposed therebetween. A publication discloses an annular floating body mounted on a wind turbine tower and a method for at least partially eliminating the heave motion of the floating body. A publication discloses a floating wind power generation device including a main floating body and an auxiliary floating body connected to the main floating body, with a plurality of wind power generators vertically mounted on the top of the auxiliary floating body. The floating wind power plant appears to be modified to accommodate a void and a number of auxiliary floating bodies, as disclosed in another publication, which discloses a method of constructing an elongated section for a float of a floating wind power plant, the method including assembling a number of flat panels into polyhedral sections and interconnecting the polyhedral sections in a continuous manner to form the elongated section. There is a need to improve the stability of the installed wind turbine(s), and floating foundations with large moonpools are also being investigated. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 212022920(U) [Patent Document 2] US Patent Application Publication No. 2020300224(A1) [Patent Document 3] Chinese Patent Application Publication No. 112177859(A) Summary of the Invention

[0008] The invention is as defined in the independent claims. Further embodiments of the invention are defined in the dependent claims. According to one embodiment, there is provided a floating structure comprising an open upper end, an open lower end opposite the open upper end, an annular wall extending between the open upper end and the open lower end, the annular wall forming a periphery of the floating structure to provide a central moonpool, and a cylindrical structure located off-center of the floating structure and configured to support a tower, at least a portion of the cylindrical structure extending along and coupled to the annular wall.

[0009] According to one embodiment, there is provided an apparatus including a floating structure according to the various embodiments and a tower, the tower being supported by a cylindrical structure of the floating structure and having a wind turbine mounted at a distal end of the tower.

[0010] In the drawings, like reference characters generally refer to like parts throughout the various views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the invention are described with reference to the accompanying drawings. [Brief description of the drawings]

[0011] [Figure 1A] 1 is a schematic diagram of a floating structure according to various embodiments; [Figure 1B]FIG. 1B is a schematic diagram of an apparatus including the floating structure of FIG. 1A, according to various embodiments. [Figure 2A] 1 is a schematic top view of an annular wall having a cylindrical structure according to one embodiment. FIG. [Figure 2B] 1A-1D are schematic top views of an annular wall having cylindrical structures according to different embodiments; [Figure 2C] 13 is a schematic top view of an annular wall having a cylindrical structure according to yet another different embodiment. FIG. [Diagram 3] FIG. 1 is a perspective view of a floating structure according to an embodiment. [Figure 4] FIG. 4 is a simplified top view of half of the floating structure of FIG. 3 without the skirt portion. [Diagram 5] FIG. 4 is a perspective view of an apparatus including the floating structure of FIG. 3. [Figure 6A] FIG. 4 is a simplified schematic vertical cross-sectional side view of the floating structure of FIG. 3 without a skirt portion, as viewed from line B-B'. [Figure 6B] 4 is a schematic vertical cross-sectional front view of the floating structure of FIG. 3, without a skirt portion, as viewed from line CC'. FIG. [Figure 7A] FIG. 2 is a simplified vertical cross-sectional side view schematic diagram of a floating structure according to one embodiment without a skirt portion. [Figure 7B] FIG. 7C is a schematic vertical cross-sectional front view of the floating structure of FIG. 7B without the skirt portion. [Figure 8A] FIG. 1 is a perspective view of a floating structure according to an embodiment. [Figure 8B] 1A-1C are cross-sectional side views of a portion of an annular wall having a supported skirt according to various embodiments. [Figure 8C] FIG. 8B is a vertical sectional front view of the floating structure of FIG. 8A. [Figure 9A] FIG. 8B is a perspective view of the floating structure of FIG. 8A with the upper portion cut off horizontally. [Figure 9B] FIG. 8B is a simplified horizontal cross-sectional plan schematic diagram of the annular wall of the floating structure of FIG. 8A. [Figure 10A] FIG. 1 is a perspective view of a floating structure including a multi-sided annular wall and supporting a tower, according to various embodiments. [Figure 10B] FIG. 10B is a simplified horizontal cross-sectional plan schematic diagram of the multi-sided annular wall of FIG. 10A. [Figure 11A] FIG. 2 is a simplified schematic top view of a multi-sided annular wall of a skirtless floating structure according to one embodiment. [Figure 11B] FIG. 13 is a simplified schematic top view of a multi-sided annular wall of a skirtless floating structure according to another embodiment. [Figure 11C] FIG. 2 is a simplified schematic top view of a (irregularly shaped) polygonal annular wall of a skirtless floating structure according to one embodiment. [Figure 11D] FIG. 13 is a simplified schematic top view of an (irregularly shaped) polygonal annular wall of a skirtless floating structure according to another embodiment. [Figure 12A] FIG. 10B is a partial perspective view of the floating structure of FIG. 10A with the upper portion cut off horizontally. [Figure 12B] FIG. 10B shows a partial perspective view of the floating structure of FIG. 10A. [Figure 13] 10B is a cross-sectional perspective view of the floating structure of FIG. 10A as seen from line E. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The following detailed description refers to the accompanying drawings, which show, by way of example, specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized, and structural, logical, and electrical changes may be made, without departing from the scope of the invention. Various embodiments are not necessarily mutually exclusive, as some embodiments may be combined with one or more other embodiments to form new embodiments.

[0013] An embodiment described in the context of one of a method or device is equally valid for the other method or device, and similarly, an embodiment described in the context of a method is equally valid for the device, and vice versa.

[0014] Features described in the context of one embodiment may be applicable to the same or similar features of other embodiments. Features described in the context of an embodiment may be applicable to other embodiments even if they are not explicitly described in these other embodiments. Furthermore, additions and / or combinations and / or alternatives to features described in the context of an embodiment may be applicable to the same or similar features of the other embodiments.

[0015] In the context of various embodiments, the articles "a," "an," and "the" used in reference to features or elements include a reference to one or more of the feature or element.

[0016] In the context of various embodiments, the phrase "substantially" can include "exactly as such" and reasonable variations.

[0017] In the context of various embodiments, the term "about" or "approximately" applied to a numerical value encompasses the exact value itself as well as a reasonable discrepancy.

[0018] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0019] As used herein, a phrase of the form "at least one of A or B" can include A or B, or both A and B. Correspondingly, a phrase of the form "at least one of A or B or C," or a phrase including further listed items, can include any combination of one or more of the associated listed items.

[0020] As used herein, the phrase "configured to" can mean "made to" or "arranged to."

[0021] Various embodiments provide a floating structure having a central moonpool and a tower support to the floating structure. For example, the tower may be a vertical tower or mast of a wind turbine. In the case of having a cylindrical floating structure with a large pool, a FOWT may be provided. In the context of various embodiments, the term "cylindrical" refers to a floating structure having straight parallel vertical sides and a horizontal cross section that is a perfect circle, or an irregular circle, or a regular polygon (regular polyhedron), or an irregular polygon (polyhedron).

[0022] In FIG. 1A, a floating structure 100 according to various embodiments is presented. The floating structure 100 comprises an open upper end 102, an open lower end 104 opposite the open upper end 102, an annular wall 106 extending between the open upper end 102 and the open lower end 104, and a cylindrical structure 108 arranged off-center of the floating structure 100 as indicated by line 110 and configured to support a tower (not shown in FIG. 1A). The annular wall 106 may form the periphery of the floating structure 100 to provide a central moonpool. At least a portion of the cylindrical structure 108 extends along and is coupled to the annular wall 106. The cylindrical structure 108 may be configured and dimensioned such that when the cylindrical structure 108 is coupled to the tower, a vertical force exerted by the tower may be transferred to the floating structure 100 via the cylindrical structure 108, for example in the form of a shear force in the annular wall 106.

[0023] The floating structure 100 may be cylindrical having a central axis. Thus, the central moonpool may be disposed about or centered on the central axis, and the cylindrical structure 108 coupled to the annular wall 106 may be disposed away from the central axis.

[0024] In other words, a floating structure 100 having a central moonpool is provided, and a vertical tower (e.g., a wind turbine tower) may be connected to a cylindrical structure 108 integrated into the side of the floating structure 100, more specifically, may be disposed on or extend along the sidewall (annular wall 106) of the floating structure 100. Unlike the disclosures in prior art documents such as US Patent Application Publication No. 2020300224(A1) and China Patent Application Publication No. 112177859(A), in which the wind turbine tower is disposed on the deck of the support structure, the cylindrical structure 108 described herein does not allow the tower to be installed on the deck of the floating structure 100, since it is not disposed on top of or over the annular wall 106, either vertically or along the plane of the open upper end 102. The cylindrical structure 108 may be a cylindrical support structure or transition piece that transfers the vertical force from the tower to the side(s) or sidewall of the floating structure 100 as a shear force. The height of the cylindrical structure 108 may be determined by the vertical force from the tower and the shear area required to transfer the force. For the cylindrical structure 108 to support or connect to the vertical tower, the cylindrical structure 108 is oriented vertically and substantially parallel to the central axis of the floating structure 100 or the vertical tower. Essentially, the tower may be supported by a foundation provided by the floating structure 100.

[0025] The annular wall 106 extends upwardly from the open lower end 104 to the open upper end 102 and provides a vertical or side wall of the floating structure 100. In one example, the open upper end 102 may be a deck plate with a central opening coupled to the upper end of the annular wall 106, as shown by line 112, and the open lower end 104 may be a keel plate with a central opening coupled to the lower end of the annular wall 106, as shown by line 114. Each central opening of the deck plate and keel plate may have a diameter that substantially matches the inner diameter of the annular wall 106, which may also define the diameter of the central moonpool. In another example, the annular wall 106 may have a predetermined thickness, and when positioned vertically, annular wall 106 viewed from above (e.g., in direction T in FIG. 3 ) shows an upper end of the annular wall 106 having an opening around its center and defining an open upper end 102, while annular wall 106 viewed from below (e.g., in direction U in FIG. 3 ) shows a lower or lower end of the annular wall 106 having an opening around its center and defining an open lower end 104.

[0026] In various embodiments, the floating structure 100 may have a horizontal cross-section that is substantially circular, or substantially rectangular, or substantially polygonal when vertically oriented. In other words, the floating structure 100 may have a planar shape that is substantially circular or that is, for example, substantially rectangular or substantially polygonal.

[0027] In one example, the perimeter formed by the inner surface (or inner wall) of the annular wall 106 may follow the shape of the perimeter formed by the outer surface (or outer wall) of the annular wall 106. This may occur when the thickness of the annular wall 106 is regular. In another example, the perimeter formed by the inner surface of the annular wall 106 may differ in shape from the perimeter formed by the outer surface of the annular wall 106. This may occur when the thickness of the annular wall 106 is irregular.

[0028] Some non-limiting examples of annular walls having an inner surface with a different perimeter compared to the outer surface are shown in Figures 11A-11D. Figure 11A shows a simple top view of an annular wall 1172a having a regular dodecagonal outer surface 1106a and a circular inner surface 1170a. Figure 11B shows a simple top view of an annular wall 1106b having a regular dodecagonal outer surface 1170b and a square inner surface 1172b. Figure 11C shows a simple top view of an annular wall 1172c having an irregular dodecagonal outer surface 1106c and a circular inner surface 1170c. Figure 11D shows a simple top view of an annular wall 1172d having an irregular heptagonal outer surface 1106d and a circular inner surface 1170d.

[0029] The annular wall 106 may have an effective inner diameter and an effective outer diameter, where the effective inner diameter is greater than half the effective outer diameter, thereby allowing for a large moonpool.

[0030] It is to be appreciated and understood that a diameter is any line or chord that passes through the center of a shape and terminates at a periphery. In the context of the various embodiments, the phrase "effective inner diameter" refers to a first line that passes through the center of the annular wall 106 and terminates at the periphery of the inner surface of the annular wall 106, and the phrase "effective outer diameter" refers to a second line that passes through the center of the annular wall 106 and terminates at the periphery of the outer surface of the annular wall 106, where the first and second lines are in the same direction and where the second line is completely overlapping with the first line.

[0031] The various embodiments of the annular wall 106 described herein relate to a continuous structure. However, it should be understood and appreciated that the annular wall 106 can also take the form of an intermittent structure in which a portion or portions of the annular wall 106 may include gaps.

[0032] In various embodiments, the cylindrical structure 108 can have an upper portion disposed towards the open upper end 102 of the floating structure 100 and a base portion opposite the upper portion, the base portion being disposed towards the open lower end 104 of the floating structure 100. In one example, the base portion may be disposed flush with the open lower end 104 of the floating structure 100, thereby allowing at least a portion of the cylindrical structure 108 to extend along the entire height of the annular wall 106. In another example, the base portion may be disposed away from or before the open lower end 104 of the floating structure 100, meaning that the base portion does not reach the open lower end 104. In such a case, at least a portion of the cylindrical structure 108 may extend only partially along the height of the annular wall 106.

[0033] In one embodiment, the upper portion and the base may each be open ended to allow the lower portion of the tower to extend through and out of the cylindrical structure 108, where the cylindrical structure 108 may essentially be a through hole. In a different embodiment, the base may be bottomed such that the lower portion of the tower received within the cylindrical structure 108 rests on the bottomed base.

[0034] The cylindrical structure 108 may be sized and positioned such that an upper portion can project upward and outward away from the open upper end 102 of the floating structure 100. In other words, the upper portion of the cylindrical structure 108 may project or extend above or over the open upper end 102, and thus, it can be said that only this upper portion is not encompassed by the annular wall 106.

[0035] In one embodiment, the annular wall 106 may include a recess formed in an inner surface of the annular wall 106, the recess shaped and dimensioned to receive a first portion of the cylindrical structure 108 within the annular wall 106 or recess, with a remaining second portion of the cylindrical structure 108 extending or protruding outwardly from the inner surface, as seen in the example of FIG. 2A.

[0036] In the context of the various embodiments, the term “outwardly” can mean laterally or sideways relative to the vertically upward annular wall 106 .

[0037] In another embodiment, the annular wall 106 may include a recess formed in an outer surface of the annular wall 106, the recess shaped and dimensioned to receive a first portion of the cylindrical structure 108 within the annular wall 106 or recess, with a remaining second portion of the cylindrical structure 108 extending or protruding outwardly from the outer surface, as seen in the example of FIG. 2B.

[0038] In yet another embodiment, the annular wall may include a recess formed across the annular wall 106, the recess shaped and dimensioned to receive an intermediate portion of the cylindrical structure 108 within the annular wall 106 or recess, with a first side of the cylindrical structure 108 extending outwardly from an outer surface of the annular wall 106 and a second side of the cylindrical structure 108 extending outwardly from an inner surface of the annular wall 106, as seen in the example of FIG. 2C. The first side may be opposite the second side. The first side, second side, and intermediate portion are referenced to the longitudinal axis of the cylindrical structure 108.

[0039] In some embodiments (not shown in Figures 2A-2C), the cylindrical structure 108 may have a diameter that is much smaller than the thickness of the annular wall 106, such that the cylindrical structure 108 can be positioned within the annular wall 106, i.e., has no lateral protrusions, but the upper portion of the cylindrical structure 108 remains accessible to receive and support a tower.

[0040] Exemplary shear joints may include supports, connectors, and beams. The supports may be girders (or separate beams), column flanges, or column webs. The connectors may be bolted or welded to the supports and beams. In various embodiments, the cylindrical structure 108 may be coupled to the annular wall 106 via vertical shear joints. By doing so, the vertical forces exerted by the tower may be transferred to the floating structure 100 via the cylindrical structure 108 in the form of shear forces in the annular wall 106. In one example, the vertical shear joints may extend along the entire (or substantially the entire) height of the cylindrical structure 108 where the cylindrical structure 108 joins to the annular wall 106. In another example, the vertical shear joints may extend along the height of the cylindrical structure 108, in which case the cylindrical structure 108 joins to the annular wall 106 only partially. Without being limited to the mentioned examples, the vertical shear joints may be provided in a continuous or intermittent form at regular or irregular intervals.

[0041] The floating structure 100 may include fastening means configured to secure the tower to the floating structure 100. For example, the tower may be connected to the top of the cylindrical structure 108 (near or at the top portion). The cylindrical structure 108 may transfer forces and moments from the tower to the floating structure 100. The height of the cylindrical structure 108 may depend on or be prescribed by the vertical loads and moments transferred from the tower. The moments may be prescribed by the height of the tower and the weight of the turbine (including nacelle and blades) and the tower.

[0042] For example, the fastening means may be provided by a connection between the tower and the cylindrical structure 108, such as a welded connection, a flanged connection, a slip joint connection, or other type of connection.

[0043] In various embodiments, the floating structure 100 may further include a skirt coupled towards the open lower end 104 of the floating structure 100. The skirt may be coupled to at least one of the outer surface of the annular wall 106 or the inner surface of the annular wall 106. The skirt may be of a height that allows the skirt to be fully immersed below the initial waterline when the floating structure 100 is deployed in water. The skirt may be coupled continuously around the floating structure 100 or optionally intermittently.

[0044] In one example, the skirt may comprise a non-buoyant plate or open structure, hi the alternative, the skirt may comprise a closed structure to provide buoyancy.

[0045] The skirt may have a vertical cross section of a right triangle, with the base (or adjacent side) of the skirt being aligned with or flush with the open lower end 104 of the floating structure 100, and the opposite side of the skirt being in contact with and secured to the outer surface of the annular wall 106, with the hypotenuse of the skirt sloping outwardly toward the open lower end 104. The opposite side of the skirt may refer to the right angle side that is substantially perpendicular to the base of the skirt.

[0046] The skirt may be in continuous form surrounding the annular wall 106, or the skirt may be provided by a number of shorter skirt sections that intermittently surround the annular wall 106. The skirt may be supported by columns, hopper plates, or braces.

[0047] In various embodiments, the floating structure 100 may be configured such that when the floating structure 100 moves in a natural period in heave (up and down motion) in water, due to waves of the same period, the vertical motion of the water mass in the central moonpool moves in the same phase as the waves. The floating structure 100 may be configured such that the vertical vibration piston mode natural period T piston is the natural period T of the floating structure 100 while the floating structure 100 is operating in heave.heave It may further be configured to be about 1.23 times (but less than 1.25 times) of.

[0048] The floating structure 100 may further include at least one of a ballast tank that provides stability to the floating structure 100 when operating underwater at various drafts, a mooring system including mooring lines configured to be coupled to at least one of the open upper end 102 or the open lower end 104 or the annular wall 106 of the floating structure 100, and a cable system including power cables for transmitting power disposed within the cylindrical structure 108.

[0049] The ballast tanks may be divided vertically or by a combination of vertical and horizontal watertight structures. Seawater may be used as ballast. Water ballast may be pumped into and pumped out of each ballast tank by a ballast system installed on the floating structure 100, or by pumping water in and out of each tank using hoses and pumps of a maintenance vessel, or by using hoses and temporary pumps of the floating structure 100.

[0050] In Figure 1B, an apparatus 120 is presented that includes a floating structure 100 according to various embodiments and a tower 130 supported by a cylindrical structure 108 of the floating structure 100, as indicated by line 132. The wind turbine may be mounted at a distal end of the tower 130, opposite a base or portion of the tower 130 received in or by the cylindrical structure 108.

[0051] Examples of floating structures and devices including the same are described in further detail below.

[0052] Fig. 3 is a perspective view of a floating structure 300 according to an example, and Fig. 4 is a simplified top view of half of the floating structure 300, taken along line A-A'. The floating structure 300 can be deployed in deeper waters, as seen in the device 520 of Fig. 5, with a tower 530 having a wind turbine 532 thereon, where the tower 530 is received and supported by the floating structure 300.

[0053] The floating structure 300 may include elements or components that are the same as or similar to the elements or components of the floating structure 100 of Figure 1A and therefore are assigned numbers having the same suffix numbers, and similar elements may be as described in the context of the floating structure 100 of Figure 1A, so corresponding descriptions will be omitted here.

[0054] The floating structure 300 has an inner surface or inner wall diameter d B is the diameter D of the outer surface or wall B It has a large moonpool that is larger than half of the B >D B / 2). The floating structure 300 may have a cylindrical shape and an annular wall 306 that defines a central moonpool 303. The annular wall 306 may be of a substantially constant height around the periphery of the floating structure 300. In other examples (not shown), the floating structure 300 may have a different shape and / or the annular wall 306 may not have a constant height around the periphery of the floating structure 300, but still provide a central moonpool.

[0055] The floating structure 300 for the turbine (interchangeably referred to as a floating foundation) may be a small waterplane area cylindrical hull (SWACH). The floating structure 300 heaves and the natural period T of the vertical oscillation piston mode of the water mass in the central moonpool 303 piston is the natural period T of the floating structure 300. heave It can be configured to be smaller than

[0056] As can be seen in Figure 4, the diameter DA The cylindrical structure 308 has an outer diameter (effective outer diameter) D B and inner diameter (effective inner diameter) d B 306, where D A < <D B In general, the cylindrical structure 308 has a thickness that is less than its diameter and may be significantly less than the outer diameter (effective outer diameter) of the annular wall 306. For simplicity, D A may represent the outer diameter of the cylindrical structure 308.

[0057] In some embodiments, the area of ​​the annular wall 306 below the tower 530 may also be increased in thickness. The cylindrical structure 308 may also provide additional buoyancy below the tower 530, reducing the need for right-ballasting on the side of the floating structure 300 opposite the location of the cylindrical structure 308.

[0058] The cylindrical structure 308 may be coupled to the inner surface of the annular wall 306 using shear joints 313a, 313b. The shear joints 313a, 313b may be vertical shear joints located across the boundary where the cylindrical structure 308 projects laterally and outwardly from the annular wall 306. In Figures 3 and 4, the shear joints 313a, 313b are welded between the cylindrical structure 308 and the inner surface of the annular wall 306. In various embodiments, for example in Figure 2B, the shear joints may be welded between the cylindrical structure 108 and the outer surface of the annular wall 106, while in Figure 2C, for example, the shear joints may be welded between the cylindrical structure 108 and both the inner and outer surfaces of the annular wall 106. The shear joints may be provided along at least a portion of the height of the cylindrical structure 308 or at least a portion of the height of the annular wall 306. For example, the shear joints 313a, 313b may be provided near the open top end 302 and near the open bottom end 304. In another example, the shear joints 313a, 313b may be provided along substantially the entire boundary from the open top end 302 to the open bottom end 304.

[0059] Vertical forces and moments may be transferred from the cylindrical structure 308 to the annular wall 306. For example, a vertical force from the tower 530 may be transferred to the floating structure 300 through the cylindrical structure 308 as a shear force at the side of the floating structure 300, i.e., the annular wall 306. In other words, the vertical force may be transferred from the cylindrical structure 308 to the annular wall 306 through a vertical shear joint between the cylindrical structure 308 and the annular wall 306.

[0060] In practice, the vertical shear joints transmit vertical forces from the tower 530 and the wind turbine 532 to the floating structure 300. The vertical shear joints may be located or formed between the cylindrical structure 308 and one of the inner surface of the annular wall 306 (see also FIG. 4), or the outer surface of the annular wall 306 (compare FIG. 2B), or both the inner and outer surfaces of the annular wall 306 (compare FIG. 2C).

[0061] The cylindrical structure 308 may be oriented perpendicular and substantially parallel to the central axis of the floating structure 300 or the tower 530 .

[0062] The moment may be transferred through the horizontal stringers and deck within the floating structure 300.

[0063] The floating structure 300 may be equipped with a mooring system. Mooring lines 309a, 309b, 309c may be attached to the upper part of the floating structure 300, for example near the open upper end 302 or at the open upper end. The mooring lines 309a-309c may be grouped into three equally spaced mooring clusters 311a, 311b, 311c, with one or more lines 309a-309c in each cluster 311a-311c. In another example, the mooring lines 309a-309c may alternatively or additionally be connected to the lower part of the floating structure 300, for example near the open lower end or at the open lower end 304, and / or at an intermediate position along the annular wall 306, i.e. between the open upper end 302 and the open lower end 304 (for example, as shown in Figures 10 and 13).

[0064] 3 to 5, a portion of the cylindrical structure 308 is disposed along substantially the entire height of the annular wall 306. As seen in Fig. 6A and Fig. 6B, which show a schematic vertical cross-sectional side view of the floating structure 300 taken along line B-B' and a schematic vertical cross-sectional front view of the floating structure 300 taken along line C-C', the base 308a of the cylindrical structure 308 may be disposed in alignment with the open lower end 304 or may be flush with the open lower end, and the upper portion 308b (opposite the base 308a) may extend or protrude above the open upper end 302.

[0065] In an alternative configuration, as shown in the vertical cross-sectional side schematic view of the floating structure 700 in FIG. 7A and the vertical cross-sectional front schematic view of the floating structure 700 in FIG. 7B, a portion of the cylindrical structure 708 is arranged to extend partially along the height of the annular wall 306, for example, at about the middle or any point where it may be required to support a vertical load, allowing the cylindrical structure 708 to provide sufficient support to the tower 530, for example. In other words, the base 708a of the cylindrical structure 708 may be arranged away (spaced apart) from the open lower end 304, and the upper portion 708b (opposite the base 708a) may extend or protrude above the open upper end 302.

[0066] The floating structure 700 may include elements or components that are the same as or similar to the elements or components of the floating structure 100 of Figure 1A and therefore are assigned numbers having the same suffix numbers, and similar elements may be as described in the context of the floating structure 100 of Figure 1A, so corresponding descriptions will be omitted here.

[0067] 8A and 8C are a perspective view and a vertical cross-sectional front view, respectively, of the floating structure 700 including the skirt portions 805 and 807.

[0068] Similar to the floating structure 300 of FIG. 3, a skirt portion 805 may be attached to the lower part of the floating structure 700, more specifically to the lower part of the outer surface of the annular wall 306 to provide an outer skirt portion. The outer skirt portion 305, 805 may extend over the entire circumference of the floating structure 300, 700 and may be continuous or divided into several smaller skirt portions (not shown). Alternatively or additionally, the lower part may be attached to the inner surface of the annular wall 306, i.e., inside the moonpool, to provide an inner skirt portion. The inner skirt portion 307, 807 may extend over the entire inner circumference of the floating structure 300, 700 and may be continuous or divided into several smaller skirt portions (not shown).

[0069] The features described below may refer to the figures showing the floating structure 700, but it should be noted that these features are equally applicable to the floating structure 300 of FIG. 3A.

[0070] As shown in FIG. 8C, the floating structures 300 and 700 are aligned along the initial waterline W I It may have an outer skirt 305, 805 below it.

[0071] As shown in FIG. 8C, the floating structures 300 and 700 are aligned along the initial water level line W I It may have an inner skirt 307, 807 below it.

[0072] The skirt (outer skirt 305, 805 or inner skirt 307, 807) may be a non-buoyant plate or an open structure. In another example, the skirt (outer skirt 305, 805 or inner skirt 307, 807) may be closed to provide buoyancy.

[0073] The skirts (outer skirt 305, 805 or inner skirt 307, 807) may be supported by struts or hopper plates or by braces. Figure 8B is a cross-sectional side view showing a portion of annular wall 306 with ballast tank 811 and skirts 805, 807 supported by struts 816b, 816a.

[0074] Figure 9A is a perspective view of the floating structure 700 with a top portion cut away horizontally to expose an exemplary internal configuration of the annular wall 306. Figure 9B is a simplified horizontal cross-sectional plan view of the annular wall 306 seen in Figure 9A without the cylindrical structure 708.

[0075] With reference to Figures 8C, 9A and 9B, the floating structure 700 may be provided with ballast tanks 811 to provide sufficient stability and allow the floating structure 700 to operate at various drafts. The floating structure 700 may be divided into several ballast tanks 811 as necessary for stability. The tanks 811 may be divided vertically by vertical watertight structures 915 or may be divided by a combination of vertical watertight structures 915 and horizontal watertight structures 813. In Figure 9B, the vertical watertight structures 915 are arranged to divide into 12 parts. However, it should be understood and appreciated that other configurations may be used to divide into various numbers of parts. Seawater may be used as ballast. Water ballast may be pumped into or out of each ballast tank 811 by a ballast system (not shown) onboard the floating structure 700, or by pumping water in and out of each tank 811 using hoses and pumps (not shown) on a maintenance vessel or using hoses and temporary pumps (not shown) on the floating structure 700.

[0076] For example, the floating structure 700 may be divided into several identical watertight tanks (e.g., 811) and one watertight compartment housing the cylindrical structure 708. The watertight compartment may be provided between two adjacent vertical watertight structures 915. Substantially identical watertight tanks (e.g., 811) may facilitate mass production, logistics and assembly.

[0077] Figure 10A shows a floating structure 1000 that is similar to the floating structure 700 shown in Figure 8A, but is dodecagonal in shape and has an annular wall 1006 connected to a cylindrical structure 1008 for receiving and supporting a tower 1030 of a wind turbine 1032. Mooring lines 1009a, 1009b, 1009c may be attached at intermediate positions along the annular wall 1006 between the open upper and lower ends of the floating structure 1000.

[0078] FIG. 10B is a simplified horizontal cross-sectional top view of the cylindrical structure and the annular wall 1006 without the skirts 1005, 1007. The floating structure 1000 may be provided with ballast tanks 1011 to provide sufficient stability and to operate the floating structure 1000 at various drafts. The floating structure 1000 may be divided into several ballast tanks 1011 as required for stability. The tanks 1011 may be divided vertically by vertical watertight structures 1015 or by a combination of vertical watertight structures 1015 and horizontal watertight structures (not shown in FIG. 10A and FIG. 10B). In FIG. 10B, the vertical watertight structures 1015 are arranged to divide the tank into 12 parts.

[0079] Fig. 12A is a partial perspective view 1200A of the floating structure 1000 of Fig. 10A with the upper portion cut off horizontally. Fig. 12B is a perspective view 1200B which is similar to Fig. 12A but includes the upper portion. Fig. 13 is a cross-sectional perspective view of the floating structure 1000 of Fig. 10A as seen from line E.

[0080] As seen in Figures 10A, 10B, 12A, 12B and 13, the design is divided into 12 tanks 1011 (or zones) and closed at the bottom and top by annular walls 1006. All tanks / collars 1011 provide buoyancy. Eleven of the tanks / zones 1011 are generally identical in design, except for zone 1011a, which includes a cylindrical structure 1008. The volume / buoyancy of this zone 1011a can be increased by increasing the thickness of the annular wall 1006 or by the cylindrical structure 1008 extending outside the annular wall 1006 below the top of the annular wall 1006.

[0081] The tower 1030 is connected or coupled to the upwardly projecting upper portion 1008b of the cylindrical structure 1008. Thus, the tower 1030 may be seen to be disposed on top of or over the cylindrical structure 1008, or on top of or over the upper portion 1008b.

[0082] In another example (not shown in Figures 10A, 12A, 12B and 13), the interior of the cylindrical structure may not contain a ballast tank (and thus be empty, being a hollow cylindrical structure).

[0083] The floating structure 700, 1000 may be equipped with a cable system for power transmission. The power cable(s) to / from the floating structure 700, 1000 may be arranged in a cylindrical structure 708, 1008 and means (not shown) may be provided for retraction and hang-off of the cable(s). Retraction may be by temporary winches or by a sheave system and retraction winches from the support vessel.

[0084] Although the present invention has been particularly shown and described with reference to certain embodiments, it should be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the present invention is therefore indicated by the appended claims, and it is therefore intended to embrace all changes that come within the meaning and range of equivalence of the claims.

Claims

1. A floating structure, an open upper end; an open lower end opposite the open upper end; an annular wall extending between the open upper end and the open lower end; a single cylindrical structure disposed off-center of the floating structure and configured to support a tower; Equipped with the annular wall is a continuous sidewall of the floating structure or an interrupted sidewall of the floating structure including a gap to accommodate the single cylindrical structure; the annular wall defines a periphery of the floating structure to provide a central moonpool; at least a portion of the unitary cylindrical structure extends along and is coupled to the annular wall; The single cylindrical structure is connected to the annular wall via a vertical shear joint.

2. 2. The floating structure according to claim 1, having a horizontal cross section that is substantially circular, or substantially rectangular, or substantially polygonal.

3. The floating structure according to claim 1 , wherein the annular wall has an effective inner diameter and an effective outer diameter, the effective inner diameter being greater than half of the effective outer diameter.

4. 2. The floating structure of claim 1, wherein the single cylindrical structure has an upper portion disposed toward the open upper end of the floating structure and a base opposite the upper portion and disposed toward the open lower end of the floating structure.

5. The floating structure according to claim 4 , wherein the base is disposed flush with the open lower end of the floating structure.

6. The floating structure described in any one of claims 3 to 5, wherein the single cylindrical structure is dimensioned and positioned such that the upper portion protrudes upward and outward away from the open upper end of the floating structure.

7. 2. The floating structure of claim 1, wherein the annular wall includes a recess formed in an inner surface of the annular wall, the recess shaped and dimensioned to receive a first portion of the single cylindrical structure within the annular wall, with a remaining second portion of the single cylindrical structure extending or protruding outwardly from the inner surface.

8. 2. The floating structure of claim 1, wherein the annular wall includes a recess formed in an outer surface of the annular wall, the recess shaped and dimensioned to receive a first portion of the single cylindrical structure within the annular wall, and a remaining second portion of the single cylindrical structure extending or protruding outwardly from the outer surface.

9. 2. The floating structure of claim 1, wherein the annular wall includes a recess formed across the annular wall, the recess shaped and dimensioned to receive an intermediate portion of the single cylindrical structure within the annular wall, a first side of the single cylindrical structure extending outwardly from an outer surface of the annular wall, and a second side of the single cylindrical structure extending outwardly from an inner surface of the annular wall.

10. 2. The floating structure according to claim 1, wherein the floating structure comprises fastening means configured to secure the tower to the floating structure.

11. The floating structure according to claim 1 , wherein the vertical shear joint extends along the entire height of the single cylindrical structure.

12. The floating structure according to claim 1 , further comprising a skirt portion coupled towards the open lower end of the floating structure.

13. The skirt portion is an outer surface of the annular wall; or The inner surface of the annular wall The floating structure according to claim 12, wherein the floating structure is connected to at least one of the above.

14. 14. The floating structure according to claim 12 or 13, wherein the skirt portion has a height that allows the skirt portion to be completely immersed below an initial water line when the floating structure is deployed in water.

15. 13. The floating structure of claim 12, wherein the skirt is coupled continuously or optionally intermittently around the floating structure.

16. 13. The floating structure of claim 12, wherein the skirt comprises a non-buoyant plate or an open structure.

17. 13. The floating structure of claim 12, wherein the skirt portion comprises a closure structure to provide buoyancy.

18. When the floating structure is in use, the floating structure performs a heave motion, and the natural period T of the vertical vibration piston mode of the water mass in the central moonpool ｐｉｓｔｏｎ is the natural period T of the floating structure. ｈｅａｖｅ The floating structure according to claim 1, which has a size and shape such that it is smaller than

19. [0023] ballast tanks configured to provide stability for the floating structure when operating underwater at various water drafts; a mooring system including a mooring line configured to be coupled to at least one of the open upper end, the open lower end, or the annular wall of the floating structure; A cable system including a power cable for transmitting electric power, disposed within the single cylindrical structure. The floating structure according to claim 1 , further comprising at least one of:

20. The floating structure according to claim 1 ; a tower supported by the single cylindrical structure of the floating structure, the tower having a wind turbine attached to a distal end thereof; An apparatus comprising:

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