Floating structure for semi-submersible wind turbine platform

Abstract

The present invention relates to a floating structure (10, 20, 30, 40, 50, 51) for a semi-submersible wind turbine platform (100), the floating structure (10) comprising a first buoyant stabilizing column (1), a second buoyant stabilizing column (2) and a third buoyant stabilizing column (3) extending substantially vertically, and a first elongated submersible pontoon structure (11), a second elongated submersible pontoon structure (12) and a third elongated submersible pontoon structure (13) extending substantially horizontally, the floating structure (10) having a generally triangular shape in a horizontal plane, the first pontoon structure (14) and the second pontoon structure (15) extending substantially horizontally. The present invention relates to a floating structure (10, 20, 30, 40, 50, 51) in which the first pontoon structure (11), the second pontoon structure (12) and the third pontoon structure (13) form sides of a triangle, the pontoon structures (11-13) extend between the columns (1-3) at their lower parts (1c, 2c, 3c) to connect the columns (1-3), and the third pontoon structure (13) is arranged such that an upper surface (13a) of the third pontoon structure is located at a horizontally lower level than the respective upper surfaces (11a, 12a) of the first pontoon structure (11) and the second pontoon structure (12). The present invention also relates to a method for loading a set of floating structures of the above type onto a semi-submersible cargo-carrying vessel and to a vessel for transporting a set of floating structures of the above type.

Description

[Technical field]

[0001] The present invention relates to a floating structure for a semi-submersible wind turbine platform, as well as a method for loading a set of floating structures of said type onto a semi-submersible cargo-carrying vessel and to a vessel for carrying a set of floating structures of said type.

[0002] 2. Background of the Invention There is growing interest in offshore wind power, i.e. ocean-mounted wind farms / turbines that produce electricity. Such wind turbines may have fixed underwater foundations or, especially at depths greater than about 50-60 m, may be located on floating platforms anchored to the seabed.

[0003] The floating wind turbine platform may be of the semi-submersible type, comprising a semi-submersible floating structure on which the wind turbine tower is arranged. The floating structure is typically composed of a number of stabilizing buoyancy columns connected by submersible buoyancy pontoons or other connecting members. The turbine tower is typically arranged on one of the columns. An example of a semi-submersible wind turbine platform is disclosed in WO 2021 / 219787.

[0004] This type of platform is a large structure. For example, each column of a 10 MW wind turbine platform has a height of 30 m, and the distance between the columns is 60 m to 80 m. The total weight of the floating structure exceeds 3,000 tonnes. The turbine tower extends, for example, up to 150 m above sea level, and each turbine blade is more than 100 m long.

[0005] A challenge in the field of offshore wind power is the manufacture, transportation and installation of semi-submersible platforms. Towing a platform with installed wind turbine towers, blades etc. is complex and difficult, and in order to reduce the towing distance of such a completed platform, the platform is preferably arranged so that the turbine towers, turbine blades etc. are installed on the floating structure in a protected location relatively close to the final offshore installation site. If the floating structure is manufactured in a construction yard far away from the protected location, special challenges regarding transportation arise, because for example there is no construction yard suitable for such a large and heavy floating structure at or near the protected location. In such a situation, the floating structure needs to be transported over a relatively long distance.

[0006] An additional challenge for semi-submersible wind turbine platforms is to design the floating structure so that the platform is robust and stable under harsh offshore conditions and can withstand many years of operation under such conditions.

[0007] Another further challenge, of course, is that to maintain and grow interest in offshore wind power, the platforms or floating structures need to be cost-effective to manufacture, transport, install, operate etc.

[0008] Summary of the Invention It is an object of the present invention to provide a floating structure for a semi-submersible wind turbine platform, which exhibits improved characteristics with regard to stowage / stowing on a transport vessel, thereby providing a more cost-effective transportation of the floating structure without compromising its robustness and stability. A further object is to provide a method for stowing a set of such floating structures on a semi-submersible cargo carrying vessel.

[0009] The floating structure relates to a floating structure for a semi-submersible wind turbine platform, the floating structure comprising a first buoyant stabilizing column, a second buoyant stabilizing column and a third buoyant stabilizing column extending substantially vertically, and a first elongated submersible buoyant pontoon structure, a second elongated submersible buoyant pontoon structure and a third elongated submersible buoyant pontoon structure extending substantially horizontally, the floating structure having an overall triangular shape in a horizontal plane, the first pontoon structure, the second pontoon structure and the third pontoon structure forming the sides of the triangle.

[0010] The first pontoon structure extends between the first column and the second column to connect the first column and the second column, the first pontoon structure being connected to a lower portion of each of the first column and the second column. Similarly, the second pontoon structure extends between the second column and the third column to connect the second column and the third column, the second pontoon structure being connected to a lower portion of each of the second column and the third column. Furthermore, the third pontoon structure extends between the first column and the third column at a lower portion of each of the first column and the third column to connect the first column and the third column.

[0011] Each of the first pontoon structure, the second pontoon structure and the third pontoon structure has an upwardly facing upper surface. The third pontoon structure has a height lower than the height of each of the first pontoon structure and the second pontoon structure. The third pontoon structure is disposed such that its upper surface is located at a lower level than the upper surfaces of each of the first pontoon structure and the second pontoon structure.

[0012] Thus, in simple terms, the floating structure of the present disclosure resembles a delta shape primarily in the horizontal plane, with three buoyant pontoon structures forming the sides of a triangle connecting three columns located at the corners of the triangle / delta shape. The wind turbine tower may be located on one of the three columns, or alternatively on an additional column or support located on the floating structure. The delta shape is relatively simple and provides good stability and robustness of the platform.

[0013] A specific configuration of the floating structure of the present disclosure is that the height of the third pontoon structure is lower than the height of each of the first pontoon structure and the second pontoon structure, i.e., the vertical thickness of the third pontoon structure is thinner than the thickness of each of the first pontoon structure and the second pontoon structure. Furthermore, the third pontoon structure is arranged such that the upper surface of the third pontoon structure is located at a horizontally lower level than the upper surfaces of each of the first pontoon structure and the second pontoon structure. In a typical example, the lower surfaces of the three pontoon structures are substantially aligned in a horizontal plane, and preferably also aligned with the lower surfaces of the three columns, forming a substantially flat lower surface of the entire floating structure (which allows it to be stably erected on flat ground during manufacture). Since the height of the third pontoon structure part is lower than the height of each of the first pontoon structure part and the second pontoon structure part, in such a typical example of a floating structure, the upper surface of the third pontoon structure part will be located at a horizontally lower level than the upper surfaces of each of the first pontoon structure part and the second pontoon structure part.

[0014] This particular configuration offers the possibility of efficiently stowing a set of floating structures of the above type in a transport vessel by partially "inserting" the second floating structure (i.e. the edge of the Δ-shape on which the second column is located) between the first and second pontoon structures of the adjacent first floating structure, above and on top of the third pontoon structure of the first floating structure. When stowed in this way, the second floating structure takes a slightly inclined position in the horizontal plane and is partially supported by the first floating structure (the third pontoon structure of the first floating structure and, for example, a specific support surface support the second floating structure) and partially supported by the deck of the vessel (the third pontoon structure of the second floating structure and possibly also the first and third columns of the second floating structure are located on the deck and are supported by the deck). In this manner, a row of a plurality of delta-shaped floating structures may be efficiently stowed, with at least the second floating structure, the third floating structure, the fourth floating structure, etc. in the row assuming a slightly inclined position, and the first floating structure in the row may or may not be inclined relative to the horizontal plane. The structures in the stowed configuration and the procedure for achieving stowage are described in further detail below.

[0015] A major advantage of designing a floating structure as described above is that more platforms can be loaded onto the same transport vessel for transport between, for example, a construction yard and a protected location for installing the wind turbines, thereby reducing transportation costs.

[0016] Conventional delta-shaped floating structures are not adapted to be stored in a particularly efficient manner on a transport vessel. When transportation is discussed, one idea would be to simply place one floating structure next to another on the vessel, which is not efficient storage. The three connecting or pontoon structures of conventional delta-shaped floating structures are too large and too tall to allow for this type of efficient storage.

[0017] Another idea is to ship the floating structure only partially assembled to improve storage efficiency, for example by making one of the pontoon structures a separate piece that is not yet connected to the columns at either end, but this would require a high degree of assembly work after shipping, which may be impossible or at least complicated and expensive.

[0018] As will be further explained below, the floating structures of the present disclosure allow for the transportation of approximately 4-5 floating structures on a vessel that can only carry two similarly sized floating structures designed in a conventional manner when placed side-by-side on the vessel. Because the transportation of large floating structures is extremely costly, significant cost efficiencies can be realized by having a transportation vessel carry more floating structures.

[0019] The platform and floating structures are semi-submersible, meaning that the platform / floating structure can be partially below the water surface during operation. The entire pontoon structure and part of the columns are typically below the water surface. The fixing / anchoring of the platform / floating structure to the seabed may be arranged in various ways, such as catenary, taut leg or tendon moorings.

[0020] By the pontoon structure being located on the lower portion of the column, it is meant that the pontoon structure is located somewhere in the lower region of the column, and not necessarily that the pontoon structure is located at the lowest portion of the column, as the lower region of the column, and therefore also the pontoon structure, is typically submerged during operation of the platform.

[0021] The width and length of the third pontoon structure may be different from the width and length of the first pontoon structure and the second pontoon structure.

[0022] In one embodiment, each of the first pontoon structure portion, the second pontoon structure portion and the third pontoon structure portion has a downwardly facing lower surface, and the lower surface of the first pontoon structure portion, the lower surface of the second pontoon structure portion and the lower surface of the third pontoon structure portion are substantially aligned with each other in a horizontal plane.

[0023] In one embodiment, the underside of the first pontoon structure, the underside of the second pontoon structure and the underside of the third pontoon structure are substantially aligned with the downwardly facing undersides of the first buoyancy stabilization column, the second buoyancy stabilization column and the third buoyancy stabilization column, respectively. As previously mentioned, the underside of the entire floating structure is substantially flat.

[0024] In one embodiment, each of the first pontoon structure portion and the second pontoon structure portion has a downwardly facing lower surface, and the upper surface of the third pontoon structure portion is substantially aligned with the lower surface of the first pontoon structure portion and the lower surface of the second pontoon structure portion or is located at a lower level than the lower surfaces of the first pontoon structure portion and the second pontoon structure portion.

[0025] Such a platform may be stowed in the same efficient manner as described above, although the platform according to this embodiment may simplify stowage operations as it does not need to be stowed in an inclined position.

[0026] In one embodiment, the lower surface of the first pontoon structure and the lower surface of the second pontoon structure are substantially aligned with the downwardly facing lower surface of the second buoyancy stabilization column, which allows the second column of the first platform to be placed on and supported by the third pontoon structure of the second platform when the platform is stowed. In the absence of an available third pontoon structure, for example in the case of a platform located at the end of a row of similar platforms, a separate support structure can be placed under the second column to hold such platform in a horizontal position.

[0027] In one embodiment, the underside of the first pontoon structural part and the underside of the second pontoon structural part are substantially aligned with a (first) portion of the downwardly facing underside of the second buoyancy stabilization column, and another (second) portion of the downwardly facing underside of the second buoyancy stabilization column is located at a lower level. Typically, the (second) portion located at the lower level is substantially aligned with the underside of the third pontoon and with the undersides of each of the first column and the third column. In addition to the first platform being storable near the second platform with the first portion of its underside located on the third pontoon of the second platform, the second lower level portion of the underside of the second column provides an integral support to the ground (or the deck of the ship) that holds the platform in a horizontal position.

[0028] In one embodiment, the lower surface of the third pontoon structure is substantially aligned with the downwardly facing lower surface of each of the first and third buoyancy stabilization columns.

[0029] In one embodiment, the underside of the third pontoon structural portion is substantially aligned with a portion of each of the downwardly facing underside of the first buoyancy stabilizing column and the downwardly facing underside of the third buoyancy stabilizing column, and another portion of the downwardly facing underside of each of the first buoyancy stabilizing column and the third buoyancy stabilizing column is located at a higher level.

[0030] In one embodiment, the height of the third pontoon structure is less than 75%, preferably less than 50% of the height of at least one of the first and second pontoon structures. In one example, the height of each of the first and second pontoon structures is about 7m, while the height of the third pontoon structure is about 3m, and is therefore less than 50% of the height of the first and second pontoon structures. In a further example, the height of the third pontoon structure is between 2m and 4m.

[0031] In one embodiment, the height of the third pontoon structure is at least 1 m lower, preferably at least 2 m or at least 3 m lower, than the height of at least one of the first and second pontoon structure.

[0032] In one embodiment, the first pontoon structure, the second pontoon structure and the third pontoon structure have substantially equal lengths, and the floating structure may therefore have an overall equilateral triangular shape.

[0033] In one embodiment, the floating structure exhibits i) a first angle in a horizontal plane between a central longitudinal axis of the first pontoon structure part and a central longitudinal axis of the second pontoon structure part, and ii) a second angle in a horizontal plane between a) a first imaginary line between a central point of the first stabilizing column and a central point of the second stabilizing column, and b) a second imaginary line between a central point of the second stabilizing column and a central point of a third stabilizing column, the second angle being greater than the first angle.

[0034] This means that the first and second pontoon structural parts do not extend along corresponding imaginary straight lines between the center point of the second column and the center point of the first column or the center point of the third column, nor do they extend parallel to an imaginary straight line, but instead the first and second pontoon structural parts extend in a direction that deviates from the direction indicated by the center points of the columns. The second angle being greater than the first angle further means that the diverging extension directions of the first and second pontoon structural parts are such that the straight pontoon structural parts extend from the outer part of the second column to the inner part of the first column or the inner part of the third column (where "outer" and "inner" refer to the center point of the floating structure in a horizontal plane), but are not such that the straight pontoon structural parts extend from the inner part of the second column to the outer part of the first column or the outer part of the third column.

[0035] The above mentioned centre point corresponds to the centre of gravity of the column at a level associated with the lower part of the column.

[0036] The effect of configuring the floating structure to exhibit the above first and second angles is to further improve storage efficiency, allowing the floating structures to be stored more closely together. That the first and second angles and their relationship actually provide this effect is further explained and shown below.

[0037] In one embodiment, each of the first and second pontoon structures has a width that is smaller than the width of the lower part of the second stabilizing column, at least along a major part of the length of the first and second pontoon structures. That is, the overall width of the first pontoon structure and the overall width of the second pontoon structure are smaller than the width of the second column at the part of the second column to which the pontoon structure is connected. The second column may have a width that varies vertically like a cone. The width of the lower part of the second stabilizing column means the width in a direction perpendicular to the longitudinal axis of each pontoon structure. The width of the lower part of the second stabilizing column may be its diameter if the second column has a circular cross section, or more generally, the distance between the opposite sides if the cross section is, for example, polygonal. Typically, the width of the first pontoon structure and the width of the second pontoon structure are also smaller than the width of the first column and the width of the third column.

[0038] The first and second pontoon structures being narrower than the second column is particularly useful in combination with the first and second angle configurations described above. These angles can be arranged by positioning the first or second pontoon structures such that the outer side of the first or second pontoon structure, i.e. the side of the pontoon structure facing laterally away from the floating structure, is a first distance from the outer side of the second column, while the inner side of the pontoon structure (opposite the outer side of the pontoon structure) is a second distance from the inner side of the second column, the first distance being less than the second distance. The other end of the pontoon structure must be appropriately positioned on the first or third column such that the second angle is greater than the first angle. This other end of the pontoon structure may be positioned centrally relative to the first column or the third column, or may be positioned near the inner side of the first column or the inner side of the third column to increase the difference between the first angle and the second angle.

[0039] In one embodiment, the first and second pontoon structures each have an outer side facing laterally away from the floating structure, and the outer side of at least one of the first and second pontoon structures is substantially aligned with an outer side of the second stabilizing column, such that the outer side of the pontoon structure is substantially tangent to a curved side portion of the second column (e.g., if it has a circular cross section) or substantially aligned with a planar portion of the second column (e.g., if it has a polygonal cross section).

[0040] This embodiment can be combined with positioning the other end of the pontoon structure on the first column or the third column to be close to or substantially aligned with the inside of the first column or the inside of the third column, thereby creating a large difference between the first angle and the second angle, improving storage efficiency.

[0041] In one embodiment, each of the first pontoon structure section and the second pontoon structure section has an outer side facing laterally away from the floating structure and an inner side facing inward toward the floating structure, and at least one of the first pontoon structure section and the second pontoon structure section is positioned such that its outer side is closer to the corresponding outer side of the second stabilizing column than its inner side is relative to a face of the second stabilizing column opposite the outer side of the second stabilizing column.

[0042] The pontoon structure arranged in this way is therefore not located in the center of the second column, but is located near the outer side of the second column. The outer side of the pontoon structure is substantially aligned with the outer side of the second stabilizing column, which can increase the difference between the first angle and the second angle. However, if there is a certain distance between the outer side of the pontoon structure and the column, i.e., if the outer side of the pontoon structure and the outer side of the column are not perfectly aligned, the fastening of the pontoon structure to the column is typically simplified. A further reason why the outer side of the pontoon structure and the outer side of the second column are not perfectly aligned is that a certain distance may be desired between the first pontoon structure and the second pontoon structure of adjacent floating structures stored in a transport vessel.

[0043] In one embodiment, at least an outer portion of the underside of the third pontoon structure is inclined relative to a horizontal plane, and the inclination is arranged such that the outer portion of the underside of the third pontoon structure is located at a higher vertical level than the inner portion of the underside of the third pontoon structure, the inner portion being located closer to the second stabilizing column than the outer portion.

[0044] Thus, the underside of the third pontoon structure is provided with an inclined surface which serves to provide support to the floating structure when stowed on the vessel in a slightly inclined position. The inclination of the support surface must correspond to the inclined position of the stowed floating structure. The exact degree of this inclination will depend on the exact degree of inclination of the floating structure and will typically vary, for example, depending on the size and type of floating structure. For most applications, an inclination angle of 5° to 15° is considered useful. In some cases, 8° to 10° is a suitable interval.

[0045] In one embodiment, at least a portion of the lower surface of the first stabilizing column and the lower surface of the third stabilizing column are inclined with respect to a horizontal plane, the inclination being arranged to correspond to the inclination of the lower surface of the third pontoon structure. If the first and third columns are also located on the deck of the transport vessel, the floating structure is better supported if the first and third columns are also provided with inclined support surfaces. Depending on the size of the floating structure and the width of the transport vessel, the first and third columns may be located outside the deck and may be located on opposite sides when the floating structure is located on the vessel. In such a situation, providing the first and third columns with inclined support surfaces may still be advantageous, as it simplifies manufacturing (it may be easier to connect surfaces with the same inclination).

[0046] In one embodiment, the upper surface of the third pontoon structure is inclined with respect to a horizontal plane, the inclination being configured such that an outer portion of the upper surface of the third pontoon structure is located at a lower vertical level than an inner portion of the upper surface of the third pontoon structure, the inner portion being located closer to the second stabilizing column than the outer portion. This results in an inclined support surface being formed on the upper surface of the third pontoon structure. It is advantageous for at least a first floating structure in a row of floating structures to be stored on a transportation vessel to be provided with such an inclined support surface, since this allows the first floating structure to be positioned horizontally on the vessel and at the same time provides an inclined support surface for the next floating structure in the row. The lower surface of the third pontoon structure may be horizontal in this embodiment.

[0047] As mentioned above for the inclined lower support surface, the inclination of the upper support surface must also correspond to the inclined position of the stowed, i.e. "next", floating structure. Again, the inclination is between 5° and 15° or 8° and 10°. There is no advantage to providing an inclined upper support surface of the third pontoon structure for more than one floating structure in a set or row of floating structures, since the "next" floating structure and further floating structures along the row are not inclined relative to each other.

[0048] Alternatively, the first floating structure in the row may be placed in an inclined position using special supports located on the deck of the vessel, in which case there may be no advantage to providing an inclined support surface for the upper surface of the third pontoon structure in one set of floating structures or on any of the floating structures in the row.

[0049] In one embodiment, the floating structure comprises a support structure arranged on a second stabilizing column between the first pontoon structure and the second pontoon structure, which support structure may be adapted not only to stiffen the entire floating structure but also to provide a support surface for a second column of a further floating structure housed in the floating structure with the support structure and partially housed on the floating structure.

[0050] The support structure is preferably provided with a support surface arranged at substantially the same vertical height as the upper surface of the third pontoon structure, and thus located below the upper surface of the first pontoon structure and the upper surface of the second pontoon structure. The combination of i) such a support surface on the second column between the lower part of the first pontoon structure and the lower part of the second pontoon structure and ii) the upper surface of the third pontoon structure together forms a good support for a further floating structure housed in and partially housed on the floating structure with the support structure.

[0051] In one embodiment, the floating structure comprises a controllable ballast system configured to allow control of the inclination of the floating structure when floating in water. The controllable ballast system is useful not only during operation of the semi-submersible wind turbine platform, but also when arranging the set of floating structures in a row before loading the set of floating structures onto a transportation vessel, as will be further explained below.

[0052] The invention also relates to a method for loading a set of floating structures onto a semi-submersible cargo-carrying vessel, the semi-submersible cargo-carrying vessel being configured to be partially lowered below the water surface to a lower position and to be raised to an upper position to load the vessel with cargo located on the water surface above the vessel, the set of floating structures comprising at least a first and a second floating structure of the above-mentioned type. Vessels of this type are known per se. During transportation, the floating structures are located above the water surface.

[0053] The method includes providing a set of floating structures floating on water, arranging the set of floating structures in a row above a vessel when the vessel is in its lowered position, and raising the vessel to its upper position and loading the row of floating structures onto the vessel.

[0054] In one embodiment, the step of arranging the set of floating structures in a row includes a step of arranging a first floating structure and a second floating structure adjacent to each other, whereby the second floating structure is located above a third pontoon structure portion of the first floating structure, the second column of the second floating structure is positioned between the first pontoon structure portion and the second pontoon structure portion of the first floating structure, and the second column of the second floating structure is positioned closer to the second column of the first floating structure than the first column and the third column of the first floating structure.

[0055] In one embodiment, the method includes setting at least one of the first and second floating structures in an inclined position (e.g., filling with ballast) to enable the second floating structure to float above a third pontoon structure portion of the first floating structure and assume a position adjacent to the first floating structure.

[0056] As an example, the first floating structure is positioned generally horizontally and loaded with a slightly deep draft, while the second floating structure is set in an inclined position so that the third pontoon structure is located some distance below the water surface, so that the second column of the second floating structure is raised so that the lower surface of the second column is located near the water surface. Such inclination can be provided by using a controllable ballast system arranged on the floating structures. After towing the second floating structure to a position close to the first floating structure, the two floating structures can be secured to each other. The third floating structure located adjacent to the second floating structure in the row can be set in a similar inclined position, towed into position and secured to the second floating structure. A similar procedure can be used to form a row of five floating structures, for example with a fourth and a fifth floating structure.

[0057] In one embodiment, the first floating structure in the row is provided with a support structure arranged on a second stabilizing column between the first and second pontoon structures as described above, and the method includes positioning the second column of the second floating structure on the support structure of the first floating structure. As described above, the support structure can include a support surface located at an equal height to the upper part of the third pontoon structure. Preferably, all floating structures in the set of floating structures are provided with such a support structure. The method can include positioning the second column of the second floating structure on the support surface of the first floating structure and positioning the first and second pontoon structures of the second floating structure on the upper surface of the third pontoon structure of the first floating structure. The second floating structure can be supported by the support surface and the third pontoon structure of the adjacent first floating structure. When the floating structure is loaded onto a vessel, the second structure is also supported by a third pontoon structural part of the second structure itself, which is located on the deck of the vessel.

[0058] In one embodiment, the first floating structure in the row is provided with an inclined support surface on the upper surface of the third pontoon structure as described above, which allows the first floating structure to be positioned horizontally on the vessel while providing a suitable inclined support surface. Additional support members can be used to provide good support for the next floating structure in the row.

[0059] In one embodiment, the second floating structure in the row is provided with an inclined support surface on the underside of the third pontoon structure (and possibly on the underside of the first column and on the underside of the third column) as described above. The second floating structure can be positioned in a slightly inclined position on the vessel with the appropriately inclined support surface facing the vessel's deck. The first pontoon structure and the second pontoon structure of the second floating structure can be positioned on and supported by the third pontoon structure of the adjacent first floating structure. Furthermore, the second column of the second floating structure can be positioned on and supported by the support surface of the first floating structure close to the second column of the first floating structure.

[0060] In one embodiment, the step of arranging the set of floating structures in a row includes a step of arranging a first floating structure and a second floating structure adjacent to each other, whereby the first pontoon structure portion and the second pontoon structure portion of the second floating structure are located above the third pontoon structure portion of the first floating structure, the second column of the second floating structure is positioned between the first pontoon structure portion and the second pontoon structure portion of the first floating structure, and the second column of the second floating structure is positioned closer to the second column of the first floating structure than the first column and the third column of the first floating structure.

[0061] The invention also relates to a vessel carrying a set of floating structures, the set of floating structures comprising at least a first and a second floating structure of the type described above.

[0062] In one embodiment, the set of floating structures is arranged in a row with a first floating structure and a second floating structure located adjacent to each other, the second floating structure is located above (above) the third pontoon structure portion of the first floating structure, the second column of the second floating structure is positioned between the first pontoon structure portion and the second pontoon structure portion of the first floating structure, and the second column of the second floating structure is positioned closer to the second column of the first floating structure than the first column and the third column of the first floating structure.

[0063] In one embodiment, the second column of the second floating structure rests on and is supported by said support surface of the first floating structure.

[0064] When loaded onto a ship, at least a third floating structure in the row of floating structures is supported by the support surfaces and upper surfaces of the third pontoon structure parts of the adjacent floating structures, as well as by its own third pontoon structure part located on the deck of the ship.

[0065] In the description of the invention which follows, reference is made to the following figures: [Brief description of the drawings]

[0066] [Figure 1] FIG. 1 is a perspective view of a first embodiment of a floating structure according to the present disclosure. [Figure 2A] FIG. 2 is a top view of a second embodiment of a floating body structure according to the present disclosure. [Figure 2B] FIG. 2 is a longitudinal sectional view of a second embodiment of a floating body structure according to the present disclosure. [Figure 3A] FIG. 13 is a top view of a third embodiment of a floating body structure according to the present disclosure. [Figure 3B] FIG. 11 is a longitudinal sectional view of a third embodiment of the floating structure according to the present disclosure. [Figure 4] FIG. 3C is a perspective view of the floating body structure of FIGS. 3A and 3B, further comprising a support for a wind turbine tower. [Diagram 5]FIG. 2 is a schematic side view of a first set of floating structures stored in a row on the deck of a transportation vessel. [Figure 6A] FIG. 1 is a schematic side view of a first floating structure having a special design on the right side of a set of second floating structures stored in a row on the deck of a transport vessel. [Figure 6B] FIG. 13 is a schematic side view of a set of second floating structures stored in a row on the deck of a transportation vessel. [Figure 7A] FIG. 1 is a first perspective view of a set of floating structures stored in a row on the deck of a transportation vessel. [Figure 7B] FIG. 2 is a second perspective view of a set of floating structures stored in a row on the deck of a transportation vessel. [Figure 8A] 7C is a diagram showing a step-by-step method of placing a set of floating structures according to FIG. 7A and FIG. 7B on the deck of a transportation vessel. [Figure 8B] 7C is a diagram showing a step-by-step method of placing a set of floating structures according to FIG. 7A and FIG. 7B on the deck of a transportation vessel. [Figure 8C] 7C is a diagram showing a step-by-step method of placing a set of floating structures according to FIG. 7A and FIG. 7B on the deck of a transportation vessel. [Figure 8D] 7C is a diagram showing a step-by-step method of placing a set of floating structures according to FIG. 7A and FIG. 7B on the deck of a transportation vessel. [Figure 8E] 7C is a diagram showing a step-by-step method of placing a set of floating structures according to FIG. 7A and FIG. 7B on the deck of a transportation vessel. [Figure 8F] 7C is a diagram showing a step-by-step method of placing a set of floating structures according to FIG. 7A and FIG. 7B on the deck of a transportation vessel. [Figure 9A] FIG. 13 shows a comparison of storage efficiency between sets of floating structures with different floating structure designs. [Figure 9B] FIG. 13 shows a comparison of storage efficiency between sets of floating structures with different floating structure designs. [Figure 9C] FIG. 13 shows a comparison of storage efficiency between sets of floating structures with different floating structure designs. [Figure 9D] FIG. 13 shows a comparison of storage efficiency between sets of floating structures with different floating structure designs. [Figure 10] FIG. 1 illustrates a semi-submersible wind turbine platform having a floating structure according to the present disclosure. [Figure 11] FIG. 13 is a perspective view of a further embodiment of a floating body structure according to the present disclosure. [Figure 12] FIG. 13 is a side view of a further embodiment of a floating body structure according to the present disclosure. [Figure 13] FIG. 13 is a diagram showing a state in which the sets of floating structures shown in FIG. 12 are stored in a row. [Figure 14] FIG. 12 is a side view of the embodiment according to FIG. [Figure 15] FIG. 15 is a diagram showing a state in which the sets of floating structures shown in FIG. 14 are stored in a row. [Figure 16] FIG. 13 is a perspective view of a further embodiment of a floating body structure according to the present disclosure.

[0067] Description of exemplary embodiments of the present invention 1 shows a first embodiment of a floating structure 10 for a semi-submersible wind turbine platform 100. The floating structure 10 comprises a first buoyant stabilizing column 1, a second buoyant stabilizing column 2 and a third buoyant stabilizing column 3 extending substantially vertically, and a first elongated submersible pontoon structure 11, a second elongated submersible pontoon structure 12 and a third elongated submersible pontoon structure 13 extending substantially horizontally. The floating structure 10 has an overall triangular shape in the horizontal plane, with the first pontoon structure 11, the second pontoon structure 12 and the third pontoon structure 13 forming the sides of the triangle. In this example, the first pontoon structure section 11, the second pontoon structure section 12 and the third pontoon structure section 13 have substantially equal lengths and the floating structure roughly forms an equilateral triangle with a column at each corner.

[0068] As an example of size, the columns 1, 2, and 3 have a height of about 30 m to 35 m and a diameter of about 13 m. The pontoon structures 11, 12, and 13 each have a length of about 50 m to 70 m and a width of 6 m to 10 m. The first pontoon structure 11 and the second pontoon structure 12 each have a height of 6 m to 9 m.

[0069] The first pontoon structural part 11 extends between the first column 1 and the second column 2 to connect the first column 1 and the second column 2, and the first pontoon structural part 11 is connected to the lower parts 1c and 2c of the first column 1 and the second column 2. The second pontoon structural part 12 extends between the second column 2 and the third column 3 to connect the second column 2 and the third column 3, and the second pontoon structural part 12 is connected to the lower parts 2c and 3c of the second column 2 and the third column 3. The third pontoon structural part 13 extends between the first column 1 and the third column 3 to connect the first column 1 and the third column 3, and the third pontoon structural part 13 is connected to the lower parts 1c and 3c of the first column 1 and the third column 3. In this case the lower parts 1c, 2c, 3c of the columns 1, 2, 3 are the lowest possible parts of the columns. In this case all three pontoon structures 11, 12, 13 are buoyant pontoon structures.

[0070] The first pontoon structural portion 11, the second pontoon structural portion 12, and the third pontoon structural portion 13 each have a downwardly facing lower surface 11b, 12b, and 13b that are substantially aligned with each other in a horizontal plane and with the downwardly facing lower surfaces 1b, 2b, and 3b of the first buoyancy stabilization column 1, the second buoyancy stabilization column 2, and the third buoyancy stabilization column 3, respectively.

[0071] Furthermore, each of the first pontoon structure 11 and the second pontoon structure 12 has a width that is narrower than the width of the lower portion 2c of the second stabilizing column 2. As shown in Figure 1, all of the pontoon structure parts 11, 12, 13 are straight and have a width that does not change. In other embodiments, the first pontoon structure part 11 and the second pontoon structure part 12 may have another design.

[0072] As can be seen from Fig. 1, the third pontoon structure 13 has a height that is lower than the height of each of the first pontoon structure 11 and the second pontoon structure 12. As the pontoon structures in Fig. 1 are arranged at the same level, the third pontoon structure 13 is arranged such that its upper surface 13a is located at a horizontally lower level than the upper surfaces 11a, 12a of each of the first pontoon structure 11 and the second pontoon structure 12. As will be further explained below, the main purpose of the particular structure and arrangement of the third pontoon structure 13 is to enable a more space-efficient storage of floating structures on a transport vessel, thus enabling the vessel to carry more floating structures.

[0073] In the illustrated example, the height of the third pontoon structure 13 is about 3 m, while the heights of the first pontoon structure 11 and the second pontoon structure 12 are about 7 m. Thus, the height of the third pontoon structure 13 is less than 50% of the height of the first pontoon structure 11 and the second pontoon structure 12.

[0074] The floating structure 10 is further provided with a controllable ballast system (not shown), which is configured to enable control of the inclination of the floating structure 10 when floating in water.

[0075] The embodiments of the floating structure shown in Figures 2 to 10 are basically configured in the same manner as the floating structure 10 shown in Figure 1, and therefore the same reference symbols are used in all figures for similar components.

[0076] 2A-2B show a top view (FIG. 2A) and a longitudinal section (FIG. 2B) of a second embodiment of a floating structure 20 for a semi-submersible wind turbine platform 100. As shown in FIG.

[0077] As shown in FIG. 2A, the floating structure 20 shows a first angle α in a horizontal plane between the central longitudinal axis 11c of the first pontoon structure 11 and the central longitudinal axis 12c of the second pontoon structure 12 (i.e., the angle between the axis of the centerline of the first pontoon structure 11 and the axis of the centerline of the second pontoon structure 12). The floating structure 20 further shows a second angle β in a horizontal plane between a) a first imaginary line 21 between the center point of the first stabilizing column 1 and the center point of the second stabilizing column 2, and b) a second imaginary line 22 between the center point of the second stabilizing column 2 and the center point of the third stabilizing column 3. As further shown in FIG. 2A, the second angle β is greater than the first angle α. This further improves the space efficiency of the storage of the floating structure, as will be further explained below.

[0078] As shown in FIG. 2B, the lower surface 13b of the third pontoon structure 13 is inclined with respect to the horizontal plane to form an inclined surface 130. The inclination has an angle γ with respect to the horizontal plane, and the inclination is oriented such that the outer portion of the lower surface 13b of the third pontoon structure 13 is located at a higher vertical level than the inner portion of the lower surface 13b of the third pontoon structure 13, the inner portion being located closer to the second stabilizing column 2 than the outer portion. The inclined surface 130 forms a support surface for the floating structure 20 when the floating structure 20 is stowed on the deck of the transport vessel in a slightly inclined position (angle γ), which will be further described below. Also, the lower surface 1b of the first stabilizing column 1 and a portion of the lower surface 3b of the third stabilizing column 3 are inclined at an angle γ with respect to the horizontal plane to correspond to the inclined surface 130.

[0079] The floating structure 20 is further provided with a support structure 5 arranged on the second stabilizing column 2 between the first pontoon structure 11 and the second pontoon structure 12. The support structure 5 connects the first pontoon structure 11 and the second pontoon structure 12 to the entire floating structure 20. The support structure 5 comprises a support surface 6 extending between the first pontoon structure 11 and the second pontoon structure 12 at a height corresponding to the height of the upper surface 13a of the third pontoon structure 13. The support surface 6 serves as a support for the adjacent floating structures when the set of floating structures is stowed on a transport vessel, as will be further explained below.

[0080] The floating structure 20 is further provided with braces 7 extending between and connecting the columns 1, 2, 3, essentially similar to the pontoon structures 11, 12, 13, but arranged between the upper parts of the columns 1, 2, 3. The braces between the first column 1 and the third column 3 are not installed when the floating structure is stowed for transport, because the braces would prevent compact storage. The end parts of the braces are pre-attached to the first and third columns, and the remaining parts are installed after transport. Assembly of the braces after transport is generally not very complicated.

[0081] A further difference between the floating structure of Fig. 1 and the floating structure of Fig. 2A-2B is that the second column 2 of the floating structure 20 of Fig. 2A-2B is somewhat larger (in diameter) compared to the first column 1 and the third column 3. The purpose is to provide better support conditions for placing a wind turbine tower on the second column 2. A further purpose may be to adjust the longitudinal center of buoyancy (LCF) of the floating structure, since a larger diameter of the second column means a larger cross-sectional area, which means that when the floating structure / platform is operating with the pontoon structure below the water surface and the columns penetrating the water surface, the second column presents a larger waterline area than the other columns. The position of the LCF depends on the waterline area of ​​the columns, and by adjusting the LCF, the movement of the floating structure / platform can be reduced when operating in the open sea.

[0082] 3A-3B show a top view (FIG. 3A) and a longitudinal cross-sectional view (FIG. 3B) of a third embodiment of a floating structure 30. The floating structure 30 of FIG. 3A-3B is basically similar to the floating structure 20 of FIG. 2A-2B. The difference is mainly that the first pontoon structural part 11 and the second pontoon structural part 12 of the floating structure 30 are arranged to reduce the first angle α and thus increase the difference between the second angle β and the first angle α. The first angle α can be further reduced by using a second column with a larger diameter.

[0083] As shown in Fig. 3A, each of the first pontoon structure 11 and the second pontoon structure 12 has an outer side 11d, 12d facing laterally away from the floating structure 30. In the embodiment of Fig. 3, the first pontoon structure 11 and the second pontoon structure 12 are arranged such that the outer side 11d, 12d of each of the first pontoon structure 11 and the second pontoon structure 12 is substantially aligned with the outer side 2d of the second stabilizing column 2. In addition, the opposing ends of the first pontoon structure 11 and the second pontoon structure 12 are substantially aligned with the inner side of the first stabilizing column 1 and the inner side of the third stabilizing column 3, respectively.

[0084] Further increasing the difference between the second angle β and the first angle α further improves the ability to space-efficiently store the floating structure 30 on a transportation vessel.

[0085] FIG. 4 shows a perspective view of the floating structure 30 of FIG. 3 further provided with an interface / support 101 for a wind turbine tower located on top of the second stabilizing column 2.

[0086] FIG. 5 shows a schematic side view of a first set of floating structures 20, 30, five in this example, stowed in a row on the deck 65 of a transport vessel. The floating structures of FIG. 5 may be of the type shown in FIG. 2 or FIG. 3. All five floating structures are in an inclined position with an inclination angle γ corresponding to the inclined surface 130 of the lower surface 13b of the third pontoon structure part 13. The rightmost floating structure is supported under its second column 2 by a support 66 arranged on the deck 65 of the vessel. The remaining floating structures are similarly stowed and supported, i.e. the second column 2 is supported by the support surface 6 of the adjacent floating structure, and the inclined support surface 130 is flush with and supported by the deck 65. Furthermore, the first pontoon structure portion 11 and the second pontoon structure portion 12 of these remaining floating structures are arranged on and supported by the third pontoon structure portion 13 of the adjacent floating structure.

[0087] 6A-6B are schematic side views showing a set of second floating structures 20, 30, 40, five in this example, stored in a row on the deck 65 of a transport vessel (FIG. 6B), with the first floating structure 40 on the right having a special design (FIG. 6A). The remaining four floating structures 20, 30 may be of the type shown in FIG. 2A or FIG. 3A.

[0088] As shown in Fig. 6A, the special floating structure 40 does not have an inclined surface 130 on the lower surface 13b of the third pontoon structure 13, but instead the lower surface 13b is flat. However, the upper surface 13a of the third pontoon structure 13 of the floating structure 40 is inclined with respect to the horizontal plane, forming an upper inclined surface 140. The inclination is arranged such that the outer portion of the upper surface 13a of the third pontoon structure 13 is located at a lower vertical level than the inner portion of the upper surface 13a of the third pontoon structure 13, which is located closer to the second stabilizing column 2 than the outer portion.

[0089] This means that the special floating structure 40 may and should be placed horizontally on the deck 65 and form the end structure (the "first" structure) of the row of floating structures, as shown in FIG. 6B. This first floating structure 40 is thereby set in a very stable position on the deck 65, and no additional deck supports 66 are needed to set this floating structure in an inclined position. The next (second) floating structure 20, 30 adjacent to the first floating structure 40 takes an inclined position and is supported by the upper inclined surface 140 of the first floating structure 40 and the lower inclined surface 130 of the first floating structure 40 itself, as shown in FIG. 5. An additional support 67 may be placed under the second column 2 of the second floating structure 20, 30. The remaining three floating structures 20, 30 are stowed in the same manner as in FIG. 5.

[0090] Figures 7A-7B show first and second perspective views of a set of floating structures stored in a row on a deck 65 of a transport vessel 60 in the form of a semi-submersible cargo-carrying vessel configured to be lowered partially below the water surface to a lower position and raised to an upper position to load cargo located on the water surface above the vessel onto the vessel.

[0091] The array of floating structures in Figures 7A and 7B includes a first floating structure 40 of the type shown in Figure 6A and four further floating structures 30a-30d, each type shown in Figure 4 (with the exception that the central portion of the brace 7 between the first column 1 and the third column 3 has been removed). The floating structures in Figures 7A-7B are stored on the deck 65 in a manner essentially similar to that of the floating structure in Figure 6B.

[0092] 8A to 8F show step by step how a set of floating structures according to FIGS. 7A to 7B is arranged on the deck 65 of a transportation vessel 60. FIG.

[0093] The method for loading a set of floating structures 40, 30a to 30d onto a semi-submersible cargo-carrying vessel 60 generally includes the following steps: - providing a set of floating structures 40, 30a to 30d that float on water (Figures 8A to 8D); - arranging the set of floating structures 40, 30a-30d in a row above the vessel 60 when the vessel 60 is in its lowered position (FIG. 8E); - raising the vessel 60 to its upper position in order to load the row of floating structures 40, 30a-30d onto the vessel 60 (FIG. 8F); Includes.

[0094] As shown in FIG. 8B, the set of floating structures includes at least a first floating structure 40 and a second floating structure 30a, and the step of arranging the set of floating structures in a row includes a step of arranging the first floating structure 40 and the second floating structure 30a adjacent to each other, whereby the second floating structure 30a is located above the third pontoon structure portion 13 of the first floating structure 40, the second column 2 of the second floating structure 30a is positioned between the first pontoon structure portion 11 and the second pontoon structure portion 12 of the first floating structure 40, and the second column 2 of the second floating structure 30a is positioned closer to the second column 2 of the first floating structure 40 than the first column 1 and the third column 3 of the first floating structure 40.

[0095] As shown in Fig. 8A, the method may further include setting at least one of the first and second floating structures (in this case the second floating structure 30a, see Fig. 8A) in an inclined position, and lowering the first floating structure 40 to a slightly larger draft to allow the second floating structure 30a to float above the third pontoon structure 13 of the first floating structure 40 and take a position adjacent to the first floating structure 40 (see Fig. 8B). The second floating structure 30a is set in the inclined position using a controllable ballast system.

[0096] As shown in Figures 8B to 8E and Figures 6B, 7A, and 7B, the method may further include positioning the second column 2 of the second floating structure 30a on the support structure portions 5, 6, and 67 of the first floating structure 40.

[0097] The remaining floating structures 30b, 30c, 30d are arranged in a row, essentially as described above for the first floating structure 40 and the second floating structure 30a. For example, the third floating structure 30b in the row is set in an inclined position and moved / towed to the position of the adjacent second floating structure 30a, which is already positioned in a corresponding inclined position. Since the second floating structure 30a and the third floating structure 30b are not inclined relative to each other, no additional support 67 is required. As already described above, the third floating structure 30b is supported (or is supported when the vessel 60 is raised) by the third pontoon structure 13 and the support surface 6 of the second floating structure 30a. The third floating structure 30b is also supported by its own third pontoon structure located on the deck 65. The fourth floating structure 30c and the fifth floating structure 30d are arranged in a row in a similar manner.

[0098] It is desirable that the floating structures 40, 30a to 30d are fixed to each other before raising the ship 60. Timber elements or the like can be placed between the floating structures to prevent damage.

[0099] Figures 9A to 9D show a comparison of storage efficiency between a set of floating structures with different floating structure designs A to D. Figures 9A to 9C show floating structure designs A to C where the first angle α is equal to the second angle β (for the case β>α, see Figures 2A and 3A).

[0100] The difference between designs A to C is the position of the first pontoon structure part and the second pontoon structure part; in design A, the first pontoon structure part and the second pontoon structure part are positioned inside the column (Figure 9A), in design B, they are positioned outside the column (Figure 9B), and in design C, they are positioned in the center of the column, similar to the floating structure 10 shown in Figure 1 (Figure 9A).

[0101] Design D forms an example of a floating structure where β>α, such as similar to the floating structure 30 shown in FIG. 3A.

[0102] Designs A to D all have the same column diameter and the same pontoon structure width / depth.

[0103] 9A to 9D, the number of floating structures that can be stored in a given length of the deck of the ship 60 is three for design A, four for designs B and C, and five for design D. Therefore, it is clear that the storage efficiency of this type of Δ-shaped floating structure (i.e., a stowable Δ-shaped floating structure having a lower third pontoon structure) can be further improved by arranging the floating structures so that β>α.

[0104] The thin lines in Figures 9A-9C show the fourth and fifth floating structures in Figure 9A and the fifth floating structure in Figures 9B-9C, showing the corresponding lengths of five complete structures of different designs. These additional floating structures shown do not fit on the vessel 60.

[0105] Fig. 10 shows a semi-submersible wind power generation turbine platform 100 including the floating structure 30 shown in Fig. 4. The platform 100 is provided with a wind turbine tower 102 including three blades 103 (and a generator, etc., not shown).

[0106] Figures 11 to 16 show embodiments of floating structures 50, 51 similar to those described above, except that the first pontoon structure part 11 and the second pontoon structure part 12 each have a downwardly facing underside 11b, 12b, and the upper surface 13a of the third pontoon structure part 13 is substantially aligned with the underside 11b of the first pontoon structure part 11 and the underside 12b of the second pontoon structure part 12 or is located at a lower level than the underside 11b of the first pontoon structure part 11 and the underside 12b of the second pontoon structure part 12.

[0107] In the floating structure 50 shown in Figures 12 and 13, the underside 11b of the first pontoon structural portion 11 and the underside 12b of the second pontoon structural portion 12 are substantially aligned with the entire downwardly facing underside 2b of the second buoyancy stabilization column 2.

[0108] In the floating structure 51 shown in Figures 11, 14 and 15, the lower surface 11b of the first pontoon structural part 11 and the lower surface 12b of the second pontoon structural part 12 are substantially aligned with only a portion of the downwardly facing lower surface 2b of the second buoyancy stabilization column 2. Another portion 2e of the downwardly facing lower surface 2b of the second buoyancy stabilization column 2 is located at a lower level. As best shown in Figure 14, the (second) portion 2e located at a lower level is substantially aligned with the lower surface 13b of the third pontoon 13 and the lower surfaces of each of the first column 1 and the third column 3.

[0109] FIG. 13 shows a set of floating structures stored in rows according to FIG. 12, and FIG. 15 shows a set of floating structures stored in rows according to FIGS. 11 and 14.

[0110] In cases where there is no support available from a third pontoon, such as when the platform is at the end of a row of similar platforms or is undergoing assembly, to hold the floating structure according to Figure 12 in a substantially horizontal position, it is possible to place a separate support structure 52 below the second column, see Figure 13.

[0111] The floating structure according to Figures 11 and 14 is positioned substantially horizontally even without a separate support structure 52, because, referring to Figures 11, 14 and 15, the lower surface of the third pontoon 3, the lower surfaces of the first column 1 and the third column 3, and the (second) portion 2e of the lower surface of the second column 2 are aligned with each other.

[0112] The floating structures of Figures 11 to 16 can be positioned horizontally with small steps or slopes on the undersides of the bottom of the first pontoon 11b and the undersides of the bottom of the second pontoon 12b, thereby enabling cribbing between the first and second pontoons and the upper surfaces 13a of adjacent floating structures.

[0113] The floating structures according to Figures 11 to 16 can be positioned with a small inclination (e.g. 1° to 2°) which allows cribbing between the undersides of the bottoms of the first pontoons 11b and the undersides and upper surfaces 13a of the bottoms of the second pontoons 12b of adjacent floating structures, with wedge-shaped cribbing material of different heights being placed under the lower third pontoon 13b.

[0114] Also, in the embodiment of Figures 11-16, the pontoons 11, 12, 13 are connected to the lower parts of the columns 1, 2, 3, which means that the pontoons are typically located below the water surface when the wind turbine platform is in operation.

[0115] In the floating structure shown in FIG. 16, the lower surface of the first column 1 and the lower surface of the third column 3 have a portion 1e, 3e located at a lower level and another portion (shown as 1b and 3b in FIG. 16) located at a higher level. In this example, the lower portion 1e, 3e is aligned with the lower surface 13b of the third pontoon 13, and the upper portion 1b, 3b is aligned with the lower surface 11b of the first pontoon 11 and the lower surface 12b of the second pontoon 12. The upper portion 1b, 3b provides a useful point for lifting and moving the platform on land, for example using a so-called self-propelled module transporter. Any of the floating structures of the present disclosure may be provided with such an upper portion / lifting point.

[0116] The invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims, for example the cross-sections of the columns and the pontoon structures can be different from those illustrated, such as polygonal columns and circular or polygonal pontoon structures. [Explanation of symbols]

[0117] 1. First buoyancy stabilization column 2 Secondary buoyancy stabilization column 3. Third buoyancy stabilization column 1a, 2a, 3a Top of column 1b, 2b, 3b Underside of column 1c, 2c, 3c Lower part of column 2d Outer side of second column Lower levels of 1e and 1b Lower levels of 2e and 2b Lower levels of 3e and 3b 5 Support structure 6 Support surface of support structure 5 7. Brace 10,20,30,40,50,51 Floating structures 11 First elongated submersible pontoon structure 12 Second elongated submersible pontoon structure 13 Third slender submersible pontoon structure 11a, 12a, 13a Upper surface of pontoon structure 11b, 12b, 13b Underside of pontoon structure 11c, 12c: a central longitudinal axis of the first pontoon structure and a central longitudinal axis of the second pontoon structure 11d, 12d Outer side of the first pontoon structure and outer side of the second pontoon structure α a first angle in a horizontal plane between the central longitudinal axis of the first pontoon structure and the central longitudinal axis of the second pontoon structure 21 a first imaginary line between the center point of the first stabilizing column and the center point of the second stabilizing column 22 A second imaginary line between the center point of the second stabilizing column and the center point of the third stabilizing column β is a second angle in the horizontal plane between the first imaginary line and the second imaginary line 52 Support structure 60 Marine transport vessels 65 Decks of marine transport ships 66 First additional support 67 Second Additional Support 100 Semi-submersible wind turbine platform 101 Support for wind turbine tower 102 Wind Turbine Tower 103 Wind Turbine Blades 130 Sloping surface of the lower surface of the third pontoon structure 140 Sloping surface of the upper surface of the third pontoon structure γ inclination

Claims

1. A floating structure (10, 20, 30, 30a to 30d, 40, 50, 51) for a semi-submersible wind turbine platform (100), the floating structure (10) comprising: a first buoyancy stabilization column (1), a second buoyancy stabilization column (2), and a third buoyancy stabilization column (3) extending substantially vertically; a first elongated submersible buoyancy pontoon structure (11), a second elongated submersible buoyancy pontoon structure (12), and a third elongated submersible buoyancy pontoon structure (13) extending substantially horizontally; It is equipped with the floating structure (10, 20, 30, 40) has an overall triangular shape in a horizontal plane, and the first pontoon structure (11), the second pontoon structure (12), and the third pontoon structure (13) form sides of the triangle; the first pontoon structural portion (11) extends between the first column (1) and the second column (2) to connect the first column (1) and the second column (2), and the first pontoon structural portion (11) is connected to lower portions (1c, 2c) of the first column (1) and the second column (2); the second pontoon structural portion (12) extends between the second column (2) and the third column (3) to connect the second column (2) and the third column (3), and the second pontoon structural portion (12) is connected to lower portions (2c, 3c) of the second column (2) and the third column (3); the third pontoon structure (13) extends between the first column (1) and the third column (3) at the lower portions (1c, 3c) of the first column (1) and the third column (3) to connect the first column (1) and the third column (3); Each of the first pontoon structural portion (11), the second pontoon structural portion (12), and the third pontoon structural portion (13) has an upwardly facing upper surface (11a, 12a, 13a), the third pontoon structure (13) has a height lower than the height of each of the first pontoon structure (11) and the second pontoon structure (12); the third pontoon structure (13) is arranged such that its upper surface (13a) is located at a lower level than the upper surfaces (11a, 12a) of the first pontoon structure (11) and the second pontoon structure (12); Floating structure (10, 20, 30, 30a to 30d, 40, 50, 51).

2. 2. The floating structure (10, 20, 30, 40) according to claim 1, wherein each of the first pontoon structure (11), the second pontoon structure (12), and the third pontoon structure (13) has a downwardly facing lower surface (11b, 12b, 13b), and the lower surface of the first pontoon structure, the lower surface of the second pontoon structure, and the lower surface of the third pontoon structure are substantially aligned with each other in the horizontal plane.

3. 3. The floating structure (10, 20, 30, 40) according to claim 2, wherein the lower surface (11b) of the first pontoon structural portion (11), the lower surface (12b) of the second pontoon structural portion (12), and the lower surface (13b) of the third pontoon structural portion (13) are substantially aligned with downwardly facing lower surfaces (1b, 2b, 3b) of the first buoyancy stabilization column (1), the second buoyancy stabilization column (2), and the third buoyancy stabilization column (3), respectively.

4. 2. The floating structure (50, 51) according to claim 1, wherein each of the first pontoon structure (11) and the second pontoon structure (12) has a downwardly facing lower surface (11b, 12b), and the upper surface (13a) of the third pontoon structure (13) is substantially aligned with the lower surface (11b) of the first pontoon structure (11) and the lower surface (12b) of the second pontoon structure (12) or is located at a lower level than the lower surface (11b) of the first pontoon structure (11) and the lower surface (12b) of the second pontoon structure (12).

5. 5. The floating structure (50, 51) according to claim 4, wherein the lower surface (11b) of the first pontoon structural portion (11) and the lower surface (12b) of the second pontoon structural portion (12) are substantially aligned with the downwardly facing lower surface (2b) of the second buoyancy stabilization column (2).

6. 5. The floating structure (50, 51) according to claim 4, wherein the lower surface (11 b) of the first pontoon structural portion (11) and the lower surface (12 b) of the second pontoon structural portion (12) are substantially aligned with a portion of the downwardly facing lower surface (2 b) of the second buoyancy stabilization column (2), and another portion of the downwardly facing lower surface (2 b) of the second buoyancy stabilization column (2) is located at a lower level.

7. 5. The floating structure (50, 51) according to claim 4, wherein the lower surface (13b) of the third pontoon structure portion is substantially aligned with a downwardly facing lower surface (1b, 3b) of each of the first buoyancy stabilization column (1) and the third buoyancy stabilization column (3).

8. 5. The floating structure (50, 51) according to claim 4, wherein the lower surface (13b) of the third pontoon structural portion is substantially aligned with a portion of each of the downwardly facing lower surface (1e) of the first buoyancy stabilization column (1) and the downwardly facing lower surface (3e) of the third buoyancy stabilization column (3), and another portion of the downwardly facing lower surface (1b, 3b) of each of the first buoyancy stabilization column (1) and the third buoyancy stabilization column (3) is located at a higher level.

9. 2. The floating structure (10, 20, 30, 40, 50, 51) according to claim 1, wherein the height of the third pontoon structure (13) is less than 75%, preferably less than 50%, of the height of at least one of the first pontoon structure (11) and the second pontoon structure (12).

10. 2. The floating structure (10, 20, 30, 40, 50, 51) according to claim 1, wherein the height of the third pontoon structure (13) is at least 1 m lower, preferably at least 2 m or at least 3 m lower, than the height of at least one of the first pontoon structure (11) and the second pontoon structure (12).

11. 2. The floating structure (10, 20, 30, 40, 50, 51) according to claim 1, wherein the first pontoon structure (11), the second pontoon structure (12), and the third pontoon structure (13) have substantially equal lengths.

12. The floating structure is i) a first angle (α) in the horizontal plane between a central longitudinal axis (11c) of the first pontoon structure (11) and a central longitudinal axis (12c) of the second pontoon structure (12); ii) a second angle (β) in the horizontal plane between a) a first imaginary line (21) between the center point of the first stabilizing column (1) and the center point of the second stabilizing column (2), and b) a second imaginary line (22) between the center point of the second stabilizing column (2) and the center point of the third stabilizing column (3); indicates, the second angle (β) is greater than the first angle (α); A floating structure (10, 20, 30, 40, 50, 51) according to claim 1.

13. 2. The floating structure (10, 20, 30, 40, 50, 51) according to claim 1, wherein each of the first pontoon structure (11) and the second pontoon structure (12) has a width narrower than a width of the lower portion (2c) of the second stabilizing column (2) along at least a major portion of the length of the first pontoon structure (11) and the second pontoon structure (12).

14. 2. The floating structure (30, 40) according to claim 1, wherein each of the first pontoon structure (11) and the second pontoon structure (12) has an outer side surface (11d, 12d) facing laterally away from the floating structure (30), and the outer side surface (11d, 12d) of at least one of the first pontoon structure (11) and the second pontoon structure (12) is substantially aligned with the outer side surface (2d) of the second stabilizing column (2).

15. 2. The floating structure (20, 30) according to claim 1, wherein at least an outer portion of the lower surface (13b) of the third pontoon structural portion (13) is inclined with respect to the horizontal plane to form an inclined surface (130), the inclination being oriented such that the outer portion of the lower surface (13b) of the third pontoon structural portion (13) is located at a higher vertical level than an inner portion of the lower surface (13b) of the third pontoon structural portion (13), and the inner portion is located closer to the second stabilizing column (2) than the outer portion.

16. 16. The floating structure (20, 30) according to claim 15, wherein at least a portion of a lower surface (1 b) of the first stabilizing column (1) and a lower surface (3 b) of the third stabilizing column (3) are inclined with respect to the horizontal plane, the inclination being arranged to correspond to the inclination of the lower surface (13 b) of the third pontoon structural portion (13).

17. 2. The floating structure (40) according to claim 1, wherein the upper surface (13a) of the third pontoon structure (13) is inclined with respect to the horizontal plane to form an upper inclined surface (140), the inclination being arranged so that an outer portion of the upper surface (13a) of the third pontoon structure (13) is located at a lower vertical level than an inner portion of the upper surface (13a) of the third pontoon structure (13), the inner portion being located closer to the second stabilizing column (2) than the outer portion.

18. 2. The floating structure (20, 30, 40) according to claim 1, further comprising a support structure (5) arranged on the second stabilizing column (2) between the first pontoon structure (11) and the second pontoon structure (12).

19. 19. The floating structure (20, 30, 40) according to claim 18, wherein the support structure (5) is provided with a support surface (6) arranged at a vertical height substantially equal to the upper surface (13a) of the third pontoon structure (13).

20. 2. The floating structure (10, 20, 30, 40, 50, 51) according to claim 1, comprising a controllable ballast system configured to enable control of the inclination of the floating structure when floating in water.

21. 1. A method for loading a set of floating structures (10, 20, 30, 30a-30d, 40, 50, 51) onto a semi-submersible cargo-carrying vessel (60), the semi-submersible cargo-carrying vessel (60) being configured to be partially lowered below the water surface to a lower position and to be raised to an upper position to load the vessel with cargo located on the water surface above the vessel, the set of floating structures comprising at least a first floating structure (40, 30a) and a second floating structure (30a, 30b) arranged in accordance with any one of claims 1 to 20, the method comprising: - providing a set of said floating structures (30a to 30d, 40) floating on water; - arranging the set of floating structures (30a-30d, 40) in a row above the vessel (60) when the vessel (60) is in its lowered position; - raising the vessel (60) to its upper position and loading the row of floating structures (30a-30d, 40) onto the vessel (60); A method comprising:

22. The arrangement of the sets of floating structures (30a to 30d, 40) in a row is - arranging the first floating structure (40, 30a) and the second floating structure (30a, 30b) adjacent to each other, whereby the second floating structure (30a, 30b) is located above the third pontoon structure part of the first floating structure (40, 30a), the second column of the second floating structure (30a, 30b) is positioned between the first pontoon structure part and the second pontoon structure part of the first floating structure (40, 30a), and the second column of the second floating structure (30a, 30b) is positioned closer to the second column of the first floating structure (40, 30a) than the first column and the third column of the first floating structure (40, 30a); 22. The method of claim 21, comprising:

23. The method comprises: - setting at least one of the first floating structure (40, 30a) and the second floating structure (30a, 30b) in an inclined position so as to enable the second floating structure (30a, 30b) to float above the third pontoon structure of the first floating structure (40, 30a) and to assume a position adjacent to the first floating structure; 23. The method of claim 22, comprising:

24. The first floating structure (30a) is arranged according to claim 19, and the method comprises the steps of: - placing the second column of the second floating structure (30b) on the support surface (6) of the first floating structure (30a), and / or - positioning the first pontoon structure and the second pontoon structure of the second floating structure (30b) on the upper surface (13a) of the third pontoon structure (13) of the first floating structure (30a); 23. The method of claim 22, comprising:

25. The method of claim 21, wherein the first floating structure (40) is positioned according to claim 17.

26. 22. The method of claim 21, wherein the second floating structure (30a, 30b) is arranged according to claim 15.

27. The arrangement of the set of floating structures (50, 51) in a row includes: - arranging the first floating structure and the second floating structure adjacent to each other, whereby the first pontoon structure (11) and the second pontoon structure (12) of the second floating structure are located above the third pontoon structure (13) of the first floating structure, the second column of the second floating structure is positioned between the first pontoon structure (11) and the second pontoon structure (12) of the first floating structure, and the second column (2) of the second floating structure is positioned closer to the second column (2) of the first floating structure than the first column (1) and the third column (3) of the first floating structure; 22. The method of claim 21, comprising:

28. A vessel (60) carrying a set of floating structures (10, 20, 30, 30a-30d, 40, 50, 51), the set of floating structures comprising at least a first floating structure (40, 30a, 50, 51) and a second floating structure (30a, 30b, 50, 51) arranged according to any one of claims 1 to 20.

29. The set of floating structures (30a to 30d, 40, 50, 51) is arranged in a row with the first floating structure (40, 30a, 50, 51) and the second floating structure (30a, 30b, 50, 51) positioned adjacent to each other, and the second floating structure (30b) is positioned above the third pontoon structure portion (13) of the first floating structure (30a), and the second column (2) of the second floating structure (30b) is positioned between the first pontoon structure portion (11) and the second pontoon structure portion (12) of the first floating structure (30a), and the second column (2) of the second floating structure (30b) is positioned closer to the second column (2) of the first floating structure (30a) than the first column (1) and the third column (3) of the first floating structure (30a).

30. The ship (60) according to claim 28, wherein the first floating structure (30a) is arranged according to claim 19, the second column of the second floating structure (30b) is located on the support surface (6) of the first floating structure (30a), and the first pontoon structure portion and the second pontoon structure portion of the second floating structure (30b) are located on the upper surface (13a) of the third pontoon structure portion (13) of the first floating structure (30a).

31. 29. The vessel (60) of claim 28, wherein the first floating structure (40) is arranged according to claim 17.

32. 29. The vessel (60) of claim 28, wherein the second floating structure (30a, 30b) is arranged according to claim 18.

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