Hull structure of semi-submersible wind power platform

Abstract

The invention relates to a hull structure (10, 20, 30) for a semi-submersible wind power platform (100) wherein the hull structure comprises:-a first, a second and a third buoyant stability column (1, 2, 3) extending in a substantially vertical direction; and-first and second elongated underwater pontoon structures (11, 12) extending in a substantially horizontal direction; wherein the hull structure is further provided with first, second and third cross-braces (21, 22, 23), which extend above the first and second pontoon structures (11, 12) and connect the upper portions of the uprights (1, 2, 3), and wherein the lower side of the third cross-brace (23) is located at a higher height than the upper side of at least part of the first and second cross-braces (21, 22), the first and second hull structures according to the claims can be positioned close to each other, in which the second upright (2) of the first hull structure is located between the first and second pontoon structures (11, 12) of the second hull structure, and the first and second cross-braces (21, 22) of the second hull structure extend below the third cross-brace (23) of the first hull structure.

Description

Technical Field

[0001] The present invention relates to the hull structure of a semi-submersible wind power platform. Background Art

[0002] The industry's interest in offshore wind power (i.e., wind power stations / turbines located offshore for electricity production) is increasing. Such turbines may have a fixed underwater base, or in the case of water depths exceeding 50 - 60 meters, a floating platform moored to the seabed may be adopted.

[0003] The floating wind power platform can adopt a semi-submersible type, with the turbine arranged on a semi-submersible hull structure. Such a hull structure generally consists of several floating and stable columns connected by submerged pontoons or other connecting structures. The turbine tower is generally installed on one of the columns. For example, a semi-submersible wind power platform disclosed in patent number WO2021 / 219787.

[0004] Such platforms belong to the construction of large-scale structures. For example, for a 10MW turbine platform, each column can be up to 30 meters high, and the distance between columns may be 60 - 80 meters. The total weight of the hull structure may exceed 3000 tons. The height of the turbine tower can reach 150 meters above sea level, and the length of each turbine blade may exceed 100 meters.

[0005] One of the challenges in the offshore wind power field is the manufacturing, transportation, and installation of semi-submersible wind power platforms. The towing operation of a platform equipped with a wind tower and blades, etc. is very complex and challenging. Therefore, it is best to shorten the towing distance of the complete platform and install the wind tower and blades in a sheltered sea area relatively close to the final working sea area. If the hull structure is built at a construction site far from this sheltered sea area, the transportation of the hull structure will be a special challenge, as there are often no suitable construction sites near this sheltered sea area to build such large hull structures. In this case, the hull structure needs to be transported over a long distance.

[0006] Another challenge regarding semi-submersible wind power platforms is that their structural design must ensure sufficient strength and stability to enable them to operate for many years in the harsh sea conditions of the working sea area.

[0007] A further challenge is that the construction, transportation, installation, and operation of such platforms or hull structures must have a cost advantage to attract and increase the industry's interest in offshore wind power. Summary of the Invention

[0008] The object of the present invention is to provide a hull structure of a semi-submersible wind power platform, which exhibits optimized performance in terms of being arranged close to each other, in particular, can tightly and effectively load the hull structure onto the deck of an offshore transport ship, and enables such ships to occupy less space when moored at a construction site or port.

[0009] The present invention relates to a hull structure of a semi-submersible wind power platform, wherein the hull structure comprises: first, second and third floating stability columns extending in a substantially vertical direction; and first and second elongated underwater pontoon structures extending in a substantially horizontal direction.

[0010] The first pontoon structure extends between the first and second columns and connects the first and second columns, wherein the first pontoon structure is connected to the lower parts of the first and second columns. Similarly, the second pontoon structure extends between the second and third columns and connects the second and third columns, wherein the second pontoon structure is connected to the lower parts of the second and third columns. The first and second pontoon structures are arranged in a V-shape in the horizontal plane, wherein the first and second pontoon structures form the legs of the V-shape, and the second column is located at the junction of the legs.

[0011] The hull structure is further provided with first, second and third cross braces, which extend above the first and second pontoon structures and connect the upper parts of the columns, wherein the first cross brace is arranged between the first and second columns, wherein the second cross brace is arranged between the second and third columns, and wherein the third cross brace is arranged between the first and third columns.

[0012] The lower side of the third cross brace is located at a position higher than the upper parts of at least a part of the first and second cross braces, so that first and second hull structures of this type can be arranged close to each other, wherein the second column of the first hull structure is located between the first and second pontoon structures of the second hull structure, and the first and second cross braces of the second hull structure are located below the third cross brace of the first hull structure.

[0013] The transverse bracing members can be used to increase the strength and stability of the hull structures of the above types. Although the transverse bracing members are generally relatively small and light compared to the struts and pontoons, in absolute terms, the transverse bracing members are still large and heavy components, and they are also difficult to handle with large cranes. Therefore, it is an advantage if the transverse bracing members can be installed as completely as possible at the construction site. Usually, such transverse bracing members are indeed installed at the construction site (or it is proposed to install them on the hull structure that has not been completed at the construction site). For a hull structure with three columns, three transverse braces are usually arranged at a similar vertical height between all the columns of the hull structure. Such hull structures also cannot be arranged close to each other, even if the overall shape of the hull structure allows it, for example, the first and second pontoons form a V shape, such that another hull structure can in principle be partially inserted with its V-shaped tip located between the V-shaped legs of the other hull structure. However, the transverse bracing members will prevent such an operation.

[0014] In the hull structure of the present invention, the position of the transverse brace at the V-shaped open end (or, if the hull structure is delta-shaped, on the side of the hull structure where the third pontoon is located, as described below) is higher than the other two transverse braces. In this way, even with the transverse braces installed, two hull structures of the type of the present invention can be close to each other and partially inserted. The first and second transverse braces are located below the third transverse brace.

[0015] The close positioning of such hull structures is beneficial for efficiently loading a group of hull structures onto the deck of a marine transport ship, which is usually used to transport the hull structures from the construction site far from the sheltered location to near the final marine location as described above. This transportation cost is very high, so if more hull structures can be loaded onto the ship, the cost can be significantly reduced. Arranging a group of hull structures closely is also beneficial for occupying less space when moored at the construction site or port.

[0016] When the hull structure is in the operating state, the first, second, and third columns all have a waterplane corresponding to the designed operating waterline, at which time the first and second pontoon structures are submerged below the water surface, and the first, second, and third columns extend through the water surface.

[0017] The platform and the hull structure are semi-submersible, which means that the platform / hull structure can be partially below the water surface during operation. The entire pontoon structure and part of the columns are usually below the water surface. The ways in which the platform / hull structure is anchored / fixed to the seabed can be various.

[0018] The third transverse brace does not necessarily have to be above the first and second transverse braces throughout their entire lengths.

[0019] In one embodiment, along at least half of the first and second transverse braces closest to the second column, the lower side of the third transverse brace is located at a higher position than the upper sides of the first and second transverse braces.

[0020] In one embodiment, the lower side of the third cross brace is located at a position higher than the entire upper sides of the first and second cross braces.

[0021] In one embodiment, at least the third cross brace extends in a substantially horizontal direction. The first and second cross braces may also extend in a substantially horizontal direction.

[0022] In one embodiment, the hull structure includes a third elongated submerged connection structure that extends in a substantially horizontal direction between the lower parts of the first and third columns and / or between the first and second pontoon structures, so as to form a delta or A shape in the horizontal plane together with the first and second pontoon structures. The third connection structure may or may not be a pontoon structure. In addition, when the arrangement of the cross brace members permits, the delta and A-shaped hull structures can in principle be partially inserted into each other to achieve a compact arrangement and efficient storage.

[0023] In one embodiment, the height of the second column is less than the vertical distance between the upper side of the third connection structure and the lower side of the third cross brace. In this way, the second column of the horizontally oriented first hull structure is vertically located between the third connection structure and the third cross brace of the horizontally oriented second hull structure.

[0024] In one embodiment, the height of the third connection structure is less than the height of the first and second pontoon structures, and the third connection structure is arranged such that its upper side is located below the upper sides of the first and second pontoon structures. This makes it easier to stack two hull structures closely on a flat surface, such as the cargo deck of a ship, because the first and second pontoon structures of the first hull structure inserted into another hull structure will be located on the third connection structure of the second hull structure, and the lower the third connection structure, the smaller the inclined position that the first hull structure needs to occupy.

[0025] In one embodiment, each of the first, second, and third pontoons or connection structures has a downward-facing lower side, and the lower sides of the first, second, and third pontoons or connection structures are substantially aligned with each other in the horizontal plane. Preferably, the lower sides of the first, second, and third pontoons or connection structures are substantially aligned with the downward-facing lower sides of each of the first, second, and third floating stability columns. In this way, the entire lower side of the hull structure will be substantially aligned and flat (except for the inclined surfaces further described below by way of example).

[0026] In one embodiment, the height of the third connection structure is less than 50% of the height of at least one of the first and second pontoon structures.

[0027] Under normal circumstances, the first and second pontoon structures have the same height (and are also similar in size in other directions). For example, the height of each of the first and second pontoon structures is approximately 7 meters, while the height of the third connecting structure is approximately 3 meters, thus less than 50% of the height of the first and second pontoon structures. In another example, the height of the third connecting structure is 2 - 4 meters.

[0028] In one embodiment, the hull structure is arranged as a whole to present a V-shape, a Δ-shape or an A-shape on a horizontal plane, where the first and second pontoon structures form the two sides of the V-shape or the Δ-shape or the A-shape. The terms V-shape, Δ-shape and A-shape refer to the general shapes set by the above two or three pontoon / connecting structures.

[0029] In one embodiment, the hull structure has no other columns except the first, second and third columns. Preferably, the hull structure does not have any other pontoon structures connected to the second column.

[0030] In one embodiment, the third cross brace is a rigid structure. Rigid structures, such as steel pipes or beams, are beneficial for strengthening the hull structure during transportation and during the operation of the wind power platform.

[0031] In one embodiment, the third support is a non-rigid structure. Non-rigid structures (e.g., cables or ropes) are particularly suitable for strengthening the hull structure during the transportation of the hull structure. Such non-rigid supports can be pre-tensioned when installed on the hull structure.

[0032] The present invention also relates to a method of loading a set of hull structures of the above type onto a semi-submersible cargo ship, the semi-submersible cargo ship being designed to be able to partially submerge to a lower position below the water surface and then float up to a higher position in order to load the cargo located above the water surface of the ship onto the ship, the method comprising:

[0033] - providing a set of hull structures floating in water;

[0034] - when the ship is in the submerged position, arranging a set of hull structures in a row and positioning them above the ship; and

[0035] - lifting the ship to its floating position in order to load a row of hull structures onto the ship.

[0036] Arranging a set of hull structures closely not only helps with ship transportation but also reduces the space required for storage or mooring. The present invention also relates to a method of arranging a set of hull structures closely together, where the set of hull structures includes at least first and second hull structures of the above type. The method includes: providing a set of hull structures floating in water; and arranging the set of hull structures in a row, where the latter step includes arranging the first and second hull structures adjacent to each other such that the distance between the second upright of the second hull structure and the second upright of the first hull structure is closer than its distance from the first and third uprights of the first hull structure.

[0037] The method of arranging a set of hull structures closely together may also include arranging the first and second hull structures adjacent to each other such that the second hull structure is located above the third connecting structure of the first hull structure, and the second upright of the second hull structure is located between the first and second connecting structures of the first hull structure.

[0038] In addition, the method may further include: setting at least one of the first and second hull structures in an inclined position to allow the second hull structure to float to a position close to the first hull structure. Description of the Drawings

[0039] In the description of the present invention given below, reference is made to the following drawings, where:

[0040] Figure 1 A perspective view of a first embodiment of a hull structure according to the present disclosure is shown.

[0041] Figure 2 Shows Figure 1 different views of the embodiment ( Figure 2 A and 2B).

[0042] Figure 3 Shows Figure 1 a top view of the embodiment.

[0043] Figure 4 A perspective view of a second embodiment of a hull structure according to the present disclosure is shown.

[0044] Figure 5 Shows Figure 4 a side view of the embodiment.

[0045] Figure 6 Shows how Figure 4 a set of floating hull structures according to [the disclosure] are arranged in a row close to each other.

[0046] Figure 7 A perspective view of a third embodiment of a hull structure according to the present disclosure is shown.

[0047] Figure 8Shows how a group of floating hull structures based on Figure 7 described are arranged in a row close to each other.

[0048] Figure 9 Shows a group of floating hull structures based on Figure 7 described loaded on a sea transport ship.

[0049] Figure 10 Shows a semi-submersible wind power platform including a hull structure based on Figure 4 described. Detailed implementation mode

[0050] Figures 1 to 3 Illustrates a hull structure 10, which includes first, second, and third flotation stability columns 1, 2, 3 extending in a substantially vertical direction. The first and second long strip-shaped submerged buoy structures 11, 12 extend in a substantially horizontal direction and are connected to the columns. The design operating waterline 33 is marked on the columns. When the hull structure 10 is in the operating mode and the buoy structures 11, 12 are submerged below the water surface, the waterline 33 approximately indicates the operating waterplane.

[0051] The first and second buoy structures 11, 12 are arranged in a V shape on the horizontal plane, where the first and second buoy structures 11, 12 form the legs of the V shape and the second column 2 is located at the place where the two legs meet.

[0052] The hull structure 10 is provided with first, second, and third cross braces 21, 22, 23, which extend above the first and second buoy structures 11, 12 and connect the upper parts of the columns 1, 2, 3. The first cross brace 21 is arranged between the first and second columns 1, 2, the second cross brace 22 is arranged between the second and third columns 2, 3, and the third cross brace 23 is arranged between the first and third columns 1, 3.

[0053] In this case, all the cross braces 21, 22, 23 extend substantially horizontally. The lower side of the third cross brace 23 is located at a height higher than the upper sides of the first and second cross braces 21, 22. As will be shown below, this enables Figures 1 to 3 the first and second hull structures of the type shown in to be close to each other, where the second column 2 of the first hull structure is located between the first and second buoy structures 11, 12 of the second hull structure, and the first and second cross braces 21, 22 of the second hull structure extend below the third cross brace 23 of the first hull structure.

[0054] As an example of the dimensions, the height of the columns 1, 2, 3 can be about 30 - 35 m, and the diameter can be about 13 m. The length of each buoy structure 11, 12 can be about 50 - 70 m, and the width can be about 6 - 10 m. The height of the first and second buoy structures 11, 12 can be about 6 - 9 m.

[0055] As Figures 1 to 3 shown, the height of the second column 2 is lower than that of the first column 1 and the third column 3. Additionally, the first cross brace 21 and the second cross brace 22 are arranged on the upper side of the second column 2 and horizontally extend to the connection points at the upper parts of the first column 1 and the third column 3, and these connection points are slightly lower than the upper sides of these columns.

[0056] Figure 2 A and 2B represent the vertical distance D1 between the center of the third cross brace 23 and the common center of the first and second cross braces 21, 22. The distance D1 should be greater than half of the height (vertical thickness) of the third cross brace 23 plus half of the height (vertical thickness) of the first / second cross brace 21 / 22, so that the lower side of the third cross brace 23 is located at a position higher than the upper sides of the first and second cross braces 21, 22. As Figures 1 to 3 shown, some additional margin is appropriate.

[0057] Figure 2 The water surface 34 is further marked.

[0058] Figures 4 to 5 A second embodiment of the hull structure 20 is shown, whose main arrangement is similar to that of the embodiment in Figures 1 to 3 , and the same reference numerals are used for similar components.

[0059] Figures 4 to 5 The hull structure 20 in includes a third long strip-shaped submerged buoy structure 13, which extends in a substantially horizontal direction and connects the lower part of the first column 1 and the lower part of the third column 3. Thus, the hull structure 20 presents a Δ shape on the horizontal plane.

[0060] As Figure 5 shown, the height D2 of the second column 2 of the hull structure 20 is less than the vertical distance D3 between the upper side of the third buoy structure 13 and the lower side of the third cross brace 21. Therefore, when two hull structures of the type shown in Figures 4 to 5 are placed close to each other, the second column 2 can be vertically located between the third buoy structure 13 and the third cross brace 23.

[0061] As Figure 4 shown, additional supports 24 are installed at the tops of the first and third columns 1, 3, and the third cross brace 23 is arranged at a position higher than directly installed on the upper side of the columns.

[0062] In this example, the second column 2 is provided with or includes a fan base 101, and the fan base 101 forms the upper part of the second column 2.

[0063] The height of the third buoy structure 13 is less than the heights of the first buoy structure 11 and the second buoy structure 12, and the third buoy structure 13 is arranged such that the upper side of the third connecting structure 13 is horizontally lower than the upper sides of the first buoy structure 11 and the second buoy structure 12. The lower sides of the first, second, and third buoy structures 11, 12, 13 all face downward, and the lower sides of all the buoy structures are substantially aligned with each other on the horizontal plane. In addition, the lower sides of the buoy structures 11, 12, 13 are aligned with the lower sides of the columns 1, 2, 3. The height of the third buoy structure 13 is approximately 30% of the heights of the first buoy structure 11 and the second buoy structure 12.

[0064] As Figure 5 shown, the lower side of the third buoy structure 13 and a part of the lower sides of the first and third columns 1, 3 are inclined, as shown by the reference numeral 8 in Figure 5 . The inclination angle may be approximately 10°. The purpose of designing the inclined surface 8 is to better support them when the hull structure 20 is part of a group of similar structures when tightly stacked on a flat surface, such as the deck of a marine transport ship. When tightly stacked, the hull structures will be placed in an inclined attitude corresponding to the angle of the inclined surface 8, thus being parallel to the flat surface / ship deck.

[0065] As Figure 5 further shown, the support surface 6 is provided near the second column 2, so that the support surface 6 is arranged at the same horizontal level as the upper side of the third buoy structure 13. When multiple hull structures are tightly loaded onto, for example, a ship deck, the first hull structure is supported by the support surface 6 and the upper side of the third buoy structure 13 of the adjacent second hull structure.

[0066] Figure 6 shows how a group of floating hull structures 20a, 20b, 20c as shown in Figures 4 to 5 are arranged in a row in positions close to each other. Figure 6 A shows that the first hull structure 20a can be inclined (using a controllable ballast system provided on the hull structure) to allow the second hull structure 20b to be located "inside" the first hull structure and present the same inclination angle ( Figure 6 C). The third hull structure 20c uses the same method. When the group of hull structures 20a - 20c are tightly arranged in a row according to Figure 6 E, the group of hull structures can be loaded onto a marine transport ship of the semi-submersible cargo ship 60 (see Figure 9 ), and the semi-submersible cargo ship 60 is designed to be able to partially submerge to a lower position below the water surface and then can float to a higher position in order to load the goods located above the water surface of the ship onto the ship.

[0067] Figure 6It is shown that the inclined surfaces 8 of the hull structures 20a - 20c are all in a horizontal position. It is also shown that the second and third hull structures 20b, 20c are supported by the support surface 6 and the upper side cross brace of the third pontoon structure 13 of the adjacent hull structure on the right (or would be supported if the group of hull structures is lifted by the deck of the ship). The rightmost first hull structure 20a can be supported by additional supports arranged on the ship's deck.

[0068] Figure 7 Shows a third embodiment of the hull structure 30, which is similar in most aspects to Figures 1 to 3 the embodiment. The difference is that the hull structure 30 is provided with a fourth cross brace 24, which extends between the first and third columns 1, 3 and is located below the third cross brace 23. In order to still achieve a close storage / arrangement of a group of similar hull structures, the fourth cross brace 24 is divided into three parts: the first short end part or cross brace 24a is fixed to the third column 3, the second short end part or cross brace 24c is fixed to the first column 1, and the central part 24b that constitutes most or substantially all of the total length of the fourth cross brace 24.

[0069] The central part 24b of the fourth cross brace 24 can be disassembled and installed at the third cross brace 23. The arrangement of the central part 24b is suitable for being carried out in combination with the construction of the hull structure 30 at the construction site. In addition, the end / mounting supports 24a, 24c are preferably completed at the construction site. When the transportation of the hull structure 30 is completed (or when close storage / arrangement is not required), the central part 24b can be relatively easily fixed to the mounting supports 24a, 24c by lowering the central part 24b using a winch or similar device and then fixing it. In this way, there is no need to use a large crane to accurately place the central part 24b, because the central part 24b has been longitudinally correctly positioned and only needs to be lowered to the correct vertical position.

[0070] If the central part 24b is located below the third cross brace 23, as Figure 7 shown, an appropriate vertical spacing should be maintained between the third cross brace 23 and the first and second cross braces 21, 22 to ensure that similar hull structures can still be closely stored / arranged.

[0071] In Figure 7 the example, the second column 2 is the same as Figures 4 - 6 the example and is equipped with or includes a fan base 101. In Figure 7 the example, the upper side of the fan base 101 is located at a position higher than the third cross brace 23.

[0072] Figure 8 Shows how a group of floating hull structures 30a - 30c are arranged in a row in the case of being closely arranged with each other according to Figure 7 the example. As Figure 8As shown in FIGS. B and 8C, the hull structure is tilted (using a controllable ballast system mounted on the hull structure) to achieve a compact layout. Compared with Figure 6 The hull structures 30a - 30c are tilted in the opposite direction. Since no pontoon structure is provided between the first and third columns 1 and 3 of the hull structures 30a - 30b, the hull structures can be horizontally oriented when arranged in a row, see Figure 8 FIG. D.

[0073] Figure 9 FIG. shows a set of floating hull structures 30a - 30c according to Figure 7 which are loaded on the deck 65 of a marine transport ship 60 in the form of a semi-submersible cargo ship. The semi-submersible cargo ship is designed to be able to partially submerge to a lower position below the water surface and then float up to a higher position in order to load the cargo located above the water surface of the ship onto the ship.

[0074] A method of loading a set of hull structures 30a - 30c (or for example a set of hull structures 20a - 20c) onto a semi-submersible cargo ship 60 generally includes the following steps:

[0075] - Providing a set of hull structures 30a - 30c floating in water;

[0076] - When the ship is in the submerged position, arranging a set of hull structures 30a - 30c in a row above the ship 60; and

[0077] - Lifting the ship 60 to its floating position so as to load a set of hull structures 30a - 30c onto the ship 60.

[0078] The step of arranging a set of hull structures in a row, where the set of hull structures at least includes a first hull structure 20a and a second hull structure 20b, may include: arranging the first and second hull structures 20a, 20b adjacent to each other such that the second hull structure 20b is located above the third connection structure 13 of the first hull structure 20a, and the second column 2 of the second hull structure 20b is located between the first and second connection structures 11, 12 of the first hull structure 20a.

[0079] The step of arranging a group of hull structures in a row may further include: the group of hull structures at least includes a first hull structure 20a, 30a and a second hull structure 20b, 30b, arranging the first and second hull structures 20a, 20b, 30a, 30b adjacent to each other such that the second column 2 of the second hull structures 20b, 30b is closer to the second column 2 of the first hull structures 20a, 30a than it is to the first and third columns 1, 3 of the first hull structures 20a, 30a.

[0080] The method may further include: setting at least one of the first and second hull structures in an inclined state to allow the second hull structure to float to a position adjacent to the first hull structure.

[0081] Figure 10 A semi-submersible wind power platform 100 is shown, including a hull structure 30 according to Figure 4 The platform 100 is equipped with a wind turbine tower 102, and three wind blades 103 (and other equipment such as a generator not shown in the figure) are installed on the wind turbine tower 102.

[0082] The present invention is not limited to the above embodiments, but can be modified in various ways within the scope of the claims. For example, the cross-sections of the columns, pontoon structures, and cross braces can be different from the examples, such as polygonal columns or cross braces, circular or polygonal pontoon structures.

[0083] The third cross brace 23 can be a rigid structure, generally capable of carrying loads in two longitudinal directions, that is, it can withstand tensile and compressive forces along its longitudinal axis direction. Alternatively, the third cross brace 23 can be a metal cable, rope, or other non-rigid structure, which can be pre-tensioned during installation and is generally capable of carrying loads mainly (but not limited to) when subjected to tensile forces in the longitudinal direction. As Figure 9 shown, the first and third columns 1, 3 are located outside the ship deck 65. This means that during transportation, the first and third columns 1, 3 or at least their upper parts tend to be forced to spread out slightly, that is, the columns tend to bend or flex outward at the top, which in turn means that the third cross brace 23 will mainly be subjected to tensile forces during transportation. Both rigid and non-rigid supports can well carry such forces or loads.

[0084] Regardless of whether the third cross brace 23 is rigid or non-rigid, it can be removed after transportation. That is, when the wind power platform is operating, the third cross brace 23 may not be installed.

[0085] The rigid support can be made of a metal material (such as steel) and can be in the form of a pipe or a beam. The non-rigid support can be in the form of a cable or a rope and can be pre-tensioned to reduce the forces acting on different parts of the hull structure during transportation.

Claims

1. Hull structures (10, 20, 30) for a semi-submersible wind power platform (100), wherein, The hull structure includes: - first, second, and third buoyancy stability columns (1, 2, 3) extending in a substantially vertical direction; and - first and second elongated underwater pontoon structures (11, 12) extending in a substantially horizontal direction; wherein the first pontoon structure (11) extends and connects the first and second columns (1, 2), and the first pontoon structure (11) is connected to the lower parts of the first and second columns (1, 2); wherein the second pontoon structure (12) extends and connects the second and third columns (2, 3), and the second pontoon structure (12) is connected to the lower parts of the second and third columns (2, 3); wherein the first and second pontoon structures (11, 12) are arranged in a V shape on a horizontal plane, the first and second pontoon structures (11, 12) form the legs of the V shape, and the second column (2) is located at the intersection of the legs; wherein the hull structure is further provided with first, second, and third cross braces (21, 22, 23) that extend and connect the upper parts of the columns (1, 2, 3) at a height above the first and second pontoon structures (11, 12); wherein the first cross brace (21) is arranged between the first and second columns (1, 2), the second cross brace (22) is arranged between the second and third columns (2, 3), and the third cross brace (23) is arranged between the first and third columns (1, 3); wherein the lower side of the third cross brace (23) is located at a height higher than at least a part of the upper sides of the first and second cross braces (21, 22), such that the first and second hull structures according to this claim can be arranged close to each other, wherein the second column (2) of the first hull structure is located between the first and second pontoon structures (11, 12) of the second hull structure, and the first and second cross braces (21, 22) of the second hull structure extend below the third cross brace (23) of the first hull structure.

2. The hull structure (10, 20, 30) according to claim 1, wherein, The lower side of the third cross brace (23) is located at a height higher than the upper sides of the first and second cross braces (21, 22), and this height is at least half of the height of the first and second cross braces (21, 22) closest to the second column (2).

3. The hull structure (10, 20, 30) according to claim 1 or 2, wherein, The lower side of the third cross brace (23) is located at a height higher than the entire upper sides of the first and second cross brace members (21, 22).

4. The hull structure (10, 20, 30) according to any one of the preceding claims, wherein, At least the third cross brace (23) extends in a substantially horizontal direction.

5. The hull structure (10, 20, 30) according to any one of the preceding claims, wherein, The hull structure includes a third elongated submerged connection structure (13) that extends in a substantially horizontal direction and connects the lower parts of the first column (1) and the third column (3) and / or connects the first and second pontoon structures (11, 12), so as to form a Δ shape or an A shape on a horizontal plane together with the first and second pontoon structures (11, 12).

6. The hull structure (10, 20, 30) according to claim 5, wherein, The height of the second column (2) is less than the vertical distance between the upper side of the third connection structure (13) and the lower side of the third cross brace (23).

7. The hull structure (10, 20, 30) according to claim 6, wherein, The height of the third connection structure (13) is less than the height of the first and second pontoon structures (11, 12), and the third connection structure (13) is arranged such that the upper side of the third connection structure (13) is located at a lower height in the horizontal direction than the upper sides of the first and second pontoon structures (11, 12).

8. The hull structure (10, 20, 30) according to any one of claims 5 to 7, wherein, Each of the first, second, and third pontoons or connecting structures (11, 12, 13) has a downward-facing lower side, and wherein the lower sides of the first, second, and third pontoons or connecting structures are substantially aligned with each other in a horizontal plane, and the lower sides of the first, second, and third pontoons or connecting structures (11, 12, 13) are preferably substantially aligned with the downward-facing lower sides of the first, second, and third floating stability columns (1, 2, 3).

9. The hull structure (10, 20, 30) according to any one of claims 5 to 8, wherein, The height of the third connecting structure (13) is less than 50% of the height of at least one of the first and second pontoon structures (11, 12).

10. The hull structure (10, 20, 30) according to any one of the preceding claims, wherein, The hull structure is arranged as a whole to present a V-shape, a delta-shape, or an A-shape in a horizontal plane, wherein the first and second pontoon structures (11, 12) form the V-shape or are on both sides of the delta-shape or A-shape.

11. The hull structure (10, 20, 30) according to any one of the preceding claims, wherein, The hull structure has no other columns except the first, second, and third columns (1, 2, 3), and preferably, the hull structure is not provided with any other pontoon structures connected to the second column (2).

12. The hull structure (10, 20, 30) according to any one of the preceding claims, wherein, The third cross brace (23) is a rigid structure.

13. The hull structure (10, 20, 30) according to any one of claims 1 to 11, wherein, The third cross brace (23) is a non-rigid structure.

14. A method of loading a set of hull structures (20a - 20c, 30a - 30c) according to any one of the preceding claims onto a semi-submersible cargo ship (60), the semi-submersible cargo ship being designed to be able to partially submerge to a lower position below the water surface and then be able to float to a higher position in order to load the cargo located above the water surface of the ship (60) onto the ship (60), the method comprising: - providing a set of hull structures (20a - 20c, 30a - 30c) floating in water; - when the ship is in the submerged position, positioning a set of hull structures (20a - 20c, 30a - 30c) in a row above the ship (60); and - lifting the ship (60) to its floating position in order to load a row of hull structures (20a - 20c, 30a - 30c) onto the ship (60).

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