A high speed semi-submersible platform suitable for high sea states

Abstract

The application relates to the technical field of ocean engineering, and discloses a high-speed semi-submersible platform suitable for high sea conditions, which comprises a lower floating body, columns and an upper hull, the upper hull is horizontally arranged, the columns are provided in plurality, the upper ends of the columns are connected to the lower surface of the upper hull, the lower ends of the columns are inclined to the outer side of the upper hull, the inner side of the column is provided with an inner side amplification structure, the outer side of the column is provided with an outer side amplification structure, the lower floating body is in streamline hull structure, and two lower floating bodies are symmetrically arranged below the upper hull, the lower floating bodies are connected to the lower ends of the columns, connecting steel ropes are arranged between the lower floating bodies, and a plurality of propellers are arranged at the bow and the stern of each lower floating body, so that the structural reliability and the propelling performance of the platform are improved while the resistance is reduced. The application can guarantee that the semi-submersible platform has good strength and rapidity when the size of the semi-submersible platform is large or the sea conditions are bad, and the application can meet the requirements of scientific research and production.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and more specifically to a high-speed semi-submersible platform suitable for high sea states. Background Technology

[0002] Marine science and technology are a crucial support for building a maritime power. In the future, international marine scientific research will expand from nearshore to deep-sea and open ocean areas. The problems that come with this need to be overcome one by one. Among them, the most serious problem is the structural damage caused by the extreme marine environmental conditions in deep-sea areas. When conducting scientific research or mining operations in deep-sea areas, extreme marine environments are inevitable. Usually, when the marine environment is too harsh, marine structures will choose to evacuate to avoid danger, but this will bring a certain degree of loss to both engineering and scientific research. In addition, it is necessary to design structures to be strong enough to survive in harsh sea conditions, so that construction can be resumed immediately after the harsh environment has passed, minimizing the environmental impact.

[0003] Semi-submersible platforms, as a common type of marine structure, are widely used in offshore drilling, mining, and scientific research. The reliability of semi-submersible platform structures under normal sea conditions and at low speeds has been effectively verified. However, at high speeds or in extreme sea conditions, as the size of semi-submersible platforms gradually increases and the sea conditions they face become more severe, the overall design load of the structure increases significantly, and the overall deformation of the platform structure becomes greater. Cross bracing structures are usually installed to resist lateral tensile and compressive effects. However, when the platform undergoes large deformations, the cross bracing will inevitably deform as well, thus bearing a large amount of torsional and shear forces. The cross bracing structure will be damaged due to the large torsional and shear deformation, resulting in overall damage to the semi-submersible platform.

[0004] Therefore, the aforementioned technologies suffer from the problem of low strength of the cross bracing structure of semi-submersible platforms. When the platform is large or the sea conditions are harsh, the cross bracing structure may be damaged due to the large overall deformation of the platform. At the same time, the presence of the cross bracing generates significant additional drag and slamming loads, which have a significant impact on the platform's speed and safety. All of these factors make traditional platforms unable to meet the needs of the new generation of large-scale platforms for high-speed navigation and scientific research or production in high sea conditions. Summary of the Invention

[0005] The technical problems to be solved by the present invention are: the low strength of the existing semi-submersible platform cross bracing structure, which cannot provide effective support when the platform is large or the sea conditions are bad; and the insufficient speed of traditional platforms.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is to provide a high-speed semi-submersible platform suitable for high sea states, including a lower floating body, columns, an upper hull, and a propeller. The upper hull is horizontally arranged, and multiple columns are provided. The upper ends of the columns are connected to the lower surface of the upper hull, and the lower ends of the columns are inclined to the outer side of the upper hull. The columns are symmetrically arranged, and an inner enlarged structure is provided at the connection between the inner side of the column and the upper hull, and an outer enlarged structure is provided at the connection between the outer side of the column and the upper hull. Two lower floating bodies are provided, symmetrically arranged below the upper hull, and connected to the lower ends of the columns. Connecting steel cables connect the lower floating bodies, and the connecting steel cables are located on the lower floating bodies within the coverage area of ​​the columns. The propeller is located on the lower floating body.

[0007] By adopting the above technical solutions, inner and outer enlarged structures are set at the connection between the columns and the upper hull to ensure a good transition between the columns and the upper hull. At the same time, it can resist the bending moment transmitted from the compressive force between the lower floating bodies, reduce the lever arm, and improve the overall fatigue performance and strength of the structure. The columns are tilted to ensure that the structural load transmitted from the upper hull is converted into a sufficiently large pretension to resist the compressive force that causes the lower floating bodies to move closer together. Connecting steel cables are used to support the lower floating bodies, increasing the overall strength, and are set between the columns to avoid the deviation of the stress points. This ensures that the semi-submersible platform will not experience cross brace failure or damage when the platform size is large or the sea conditions are harsh, thus meeting the operational requirements.

[0008] Optionally, the column includes a column support section, a column middle section, a transition section, and a column square section. The upper end of the column support section is connected to the upper hull, the column middle section is connected to the lower end of the column support section, the lower end of the column square section is connected to the lower float, the column square section has the same width as the upper surface of the lower float, and the column support section connects the column middle section and the column square section.

[0009] Optionally, the middle section of the column is provided with rounded corners, and the rounded corners on the bow side are larger than those on the stern side, to reduce the column's resistance and structural stress in the water.

[0010] Optionally, the column is a double-shell structure, with an inner wall and an outer plate. A horizontal partition or horizontal bulkhead is provided between the outer plate and the inner wall to prevent structural damage caused by wave impact during operation or storage.

[0011] Optionally, the tilt angle of the column is not less than 5°.

[0012] Optionally, the upper hull can extend beyond the column range on both sides to increase the usable deck area, while ensuring that the lower hull does not extend too far for a given deck width, thus affecting the structural strength under wave action.

[0013] Optionally, the lower float is provided with multiple partition walls to divide the lower float into multiple ballast tanks, and the lower float is provided with support walls on both sides of the column.

[0014] Optionally, the lower floating body has a streamlined hull structure with a bulbous bow at the front, and the bow deck of the lower floating body is raised upwards.

[0015] By adopting the above technical solution, the bow of the lower hull is raised to avoid the resistance caused by the waves rising from the bow. A bulbous bow is set at the bow of the lower hull, which, together with the raising of the bow, ensures the platform's speed.

[0016] Optionally, the thrusters include azimuth thrusters and retractable thrusters, with multiple azimuth thrusters and retractable thrusters provided. The azimuth thrusters are located at the stern of the lower float and at the rear end of the column closest to the stern of the lower float. Each side of the lower float has one azimuth thruster with a fairing and one azimuth thruster without a fairing. The retractable thrusters are located at the bow of the lower float and at the front end of the column closest to the bow of the lower float. If there are multiple retractable thrusters, the thrusters should be arranged diagonally.

[0017] By adopting the above technical solution, four thrusters are arranged at the tail of the lower float and two telescopic thrusters are arranged at the bow of the lower float, which can ensure that the lower float has good propulsion and dynamic positioning capabilities.

[0018] Optionally, the upper hull is a rectangular box, which is divided into multiple compartments by transverse and longitudinal bulkheads. The upper hull is equipped with a living quarters, a pipe yard, and heavy cargo containers. The living quarters are located at the front of the upper hull, and their two sides do not extend beyond the vertical plane of the outer side of the columns. An elbow plate is provided at the connection between the lower end of the living quarters and the upper hull. The pipe yard and heavy cargo containers are located at the rear of the upper hull. A moon pool is provided at the center of the upper hull. A derrick is provided above the moon pool, and the lower end of the derrick is inserted into the upper hull. The living quarters, derrick, pipe yard, and heavy cargo containers are all located on the upper hull inside the columns.

[0019] In summary, the present invention has at least one of the following beneficial effects:

[0020] 1. The present invention sets an inner enlarged structure and an outer enlarged structure at the connection between the column and the upper hull to ensure a good transition between the column and the upper hull. As an integral structural elbow plate, it reduces stress concentration and reduces the lever arm between the squeezing forces that bring the hulls closer together between the lower floats, which is beneficial to improving the strength and fatigue performance of the structure at this point.

[0021] 2. The columns are tilted to ensure that the structural loads transmitted from the upper hull are converted into sufficiently large pretension to resist the squeezing force generated by waves that causes the lower floats to move closer together. Multiple connecting steel cables are used to connect the lower floats on both sides to ensure that the columns and lower floats will not separate or deform excessively under the separation force generated by waves and the pretension load transmitted from the upper hull, thus maintaining the overall performance of the platform. At the same time, the connecting steel cables are placed on the lower floats within the coverage area of ​​the columns, thereby avoiding the additional bending moment caused by the deviation of the force application points of the steel cables and columns on the lower hull, which would generate additional loads at the connection points of the lower float columns with already high stress levels. This ensures that the platform has good connection strength under any separation force. By using connecting steel cables, the problem of stress concentration in the cross bracing structure that is difficult to solve when the platform size is too large or the sea conditions are too severe is avoided.

[0022] 3. The lower floating body of this invention has a streamlined hull structure with a bulbous bow and a square stern. Except for the connecting section, the underwater part of the column has rounded corners at all four corners to avoid additional resistance from wave impact and upwelling. At the same time, compared with the cylindrical cross bracing method used in traditional platforms, the transverse connection structure of this platform is a connecting steel cable with a very small cross section, which will not produce a large damping and impact effect. The platform has better resistance performance and is conducive to improving the speed of the platform structure.

[0023] 4. The present invention has two azimuth thrusters arranged at the tail of the lower body on each side and two telescopic thrusters arranged at the bow of the lower body on each side, which can ensure that the lower body has good propulsion and dynamic positioning capabilities. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a schematic diagram of a transverse section within the column area of ​​the present invention;

[0026] Figure 3 This is a longitudinal cross-sectional view of the column area of ​​the present invention;

[0027] Figure 4 This is a schematic diagram of the horizontal cross-section of the middle section of the column;

[0028] In the diagram: 1. Lower buoy; 2. Column; 3. Upper hull; 4. Living quarters; 5. Connecting steel cables; 6. Derrick; 7. Pipe storage yard; 8. Heavy cargo container; 9. Azimuth thruster; 10. Retractable thruster; 20. Column support section; 21. Inner enlarged structure; 22. Outer enlarged structure; 23. Square section of the column; 24. Transition section; 25. Middle section of the column; 26. Outer plate of the column; 27. Inner wall of the column; 28. Horizontal bulkhead; 91. Azimuth thruster with fairing; 92. Azimuth thruster without fairing; 101. Support bulkhead; 102. Separating bulkhead. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-4 The present invention will be described in further detail below.

[0030] This invention discloses a high-speed semi-submersible platform suitable for high sea states, with reference to... Figure 1 and Figure 2 The system includes a lower float 1, pillars 2, an upper hull 3, and a propeller. The upper hull 3 is horizontally positioned. Multiple pillars 2 are provided, with their upper ends connected to the lower surface of the upper hull 3 and their lower ends inclined to the outer side of the upper hull 3 at an angle of not less than 5°. The pillars 2 are symmetrically positioned on both sides, and both sides of the upper hull 3 extend beyond the range of the pillars 2. An inner enlargement structure 21 is provided at the connection between the inner side of the pillar 2 and the upper hull 3, and an outer enlargement structure 22 is provided at the connection between the outer side of the pillar 2 and the upper hull 3. There are two lower floats 1, symmetrically positioned below the upper hull 3. The lower floats 1 are connected to the lower ends of the pillars 2, and a connecting steel cable 5 is connected between the lower floats 1. The connecting steel cable 5 is located between the front end and the rear end of the upper hull 3 pillars 2. The propeller is located on the lower float 1.

[0031] In this embodiment, four columns 2 are provided, symmetrically arranged on the port and starboard sides. The outer surface of the column 2 forms a 15° angle with the lower surface of the upper hull 3. The enlarged inner structure is a large-radius rounded shape. The diameter and end point position of the rounded shape are determined according to the actual lateral separation load. The large-radius rounded shape forms an integral structural elbow plate with the column 2, effectively increasing the module of the column connection root, reducing the lever arm length, and improving the ability to resist lateral loads. The upper hull 3 sits on the four columns 2, and the port and starboard sides of the upper hull 3 extend beyond the range of the columns 2 to increase the deck usable area, while ensuring that the lower hull is flat within a given deck width. The opening distance should not be too large, so as not to affect the structural strength under wave action. The number and size of the connecting steel cables 5 are determined according to the calculated actual separation load. There can be one or more cables. The connecting steel cables 5 are arranged near the point of application of the resultant force of the lateral load to avoid causing excessive additional bending moment. The connecting steel cables 5 are set to a pre-tensioned state to ensure that the connecting steel cables 5 will not be too loose and cause a sudden change in stress when the lateral compressive force is applied. In other embodiments, if the space is limited in the lower float 1, the position of the connecting steel cables 5 can also be moved up and down and set within the range of the column 2.

[0032] In a further implementation, refer to Figure 3 The thrusters include a full-rotation thruster 9 and a retractable thruster 10. Multiple full-rotation thrusters 9 and retractable thrusters 10 are provided. The full-rotation thruster 9 is located at the tail of the lower float 1 and at the rear end of the column 2 closest to the tail of the lower float 1. The retractable thruster 10 is located at the bow of the lower float 1 and at the front end of the column 2 closest to the bow of the lower float 1. When there are multiple retractable thrusters 10, it should be ensured that the thrusters can be arranged diagonally to avoid mutual interference between the thrusters and affect the propulsion positioning efficiency.

[0033] In this embodiment, four azimuth thrusters 9 are provided, with two azimuth thrusters 9 at the stern of each side of the lower float 1. One is an azimuth thruster 91 with a fairing, and the other is an azimuth thruster 92 without a fairing. They can be used independently under the control of the control system. In daily use, all thrusters can provide thrust. The thruster 92 without a fairing has better underwater noise performance and can be used independently in specific environments where high speed is not required. This is more conducive to meeting the underwater noise requirements of the green ship standard. At the same time, the lower underwater noise also facilitates various underwater acoustic experiments. Two retractable thrusters 10 are arranged in the lower float 1 at the front of the bow column 2. When high-precision operations are required, the retractable thrusters 10 and the azimuth thrusters 9 work together to play a role in dynamic positioning. The retractable thrusters 10 at the bow are arranged as far forward as possible, and the azimuth thrusters 9 at the stern are arranged as far aft as possible. Both should be arranged outside the range of the column 2 to ensure a sufficiently long lever arm and improve the dynamic positioning capability.

[0034] In a further implementation, refer to Figure 2 and Figure 4 The column 2 includes a column support section 20, a column middle section 25, a transition section 24, and a column square section 23. The upper end of the column support section 20 is connected to the upper hull 3. The column middle section 25 is connected to the lower end of the column support section 20. The lower end of the column square section 23 is connected to the lower floating body 1 and is arranged in the middle section of the lower floating body 1. The column square section 23 has the same width as the upper surface of the lower floating body 1. The transition section 24 connects the column middle section 25 and the column square section 23. The column middle section 25 has rounded corners on its side. In addition, the rounded corners on the side in the bow direction are larger than the rounded corners on the side in the stern direction, ensuring that the buoyancy loss of the cross section is minimized and the wave resistance is reduced to the best extent. The column 2 is a double-shell structure, with an inner column wall 27 inside and an outer column plate 26 outside. A horizontal bulkhead 28 or a horizontal block is provided between the outer column plate 26 and the inner column wall 27.

[0035] In this embodiment, the transition section 24 uses a round-to-square transition section to form a smooth transition. The outer plate shape of the entire column 2 transitions from the square section 23 of the column connected to the lower float to the rounded corner of the middle section 25 of the column through the transition section 24. The linearity of the column transition section 24 is a complex curved surface, and it should be as smooth as possible when setting it to avoid sharp points and unevenness. If the lower float 1 has linear requirements due to speed, the outer plate shape of the lower float 1 at the head column 2 position is not parallel to the middle body at the head, but is somewhat contracted. In this case, the square section 23 of the column should be stretched straight upward along the outer plate shape of the lower float 1 for a period of time, and then connected to the transition section 24.

[0036] In a further implementation, refer to Figure 3 The lower hull 1 has a streamlined hull structure. The lower hull 1 on both sides of the column 2 has supporting bulkheads 101. The supporting bulkheads 101 must be strong enough to support the column and the upper hull. The lower hull 1 also has multiple partition bulkheads 102, which divide the lower hull 1 into multiple compartments to meet the needs of ballast water, fuel or various equipment. The lower hull 1 has a bulbous bow to reduce sailing resistance. The bow deck of the lower hull 1 is raised to avoid waves hitting the bow and generating additional resistance. The height of the bow elevation needs to be determined according to the actual design. When the bow needs to be raised higher, it can be folded from the rear of the forward column 2 to ensure that the entire elevation range does not have too large abrupt changes. Alternatively, it can be in the form of a forecastle to directly add a deck and extend to the outer wall of the column 2 to form an additional box, increase the displacement and avoid the impact of waves during high-speed sailing.

[0037] In a further implementation, refer to Figure 1The upper hull 3 is a square box-shaped structure, internally divided into multiple compartments by transverse and longitudinal bulkheads. The upper hull 3 houses a living quarters 4, a pipe yard 7, and heavy cargo containers 8. The living quarters 4 are located at the front of the upper hull 3, with both sides not extending beyond the vertical plane of the outer side of the columns 2. An elbow plate is provided at the lower end of the living quarters 4 where it connects to the upper hull 3 to ensure a smooth transition of rigidity without stress concentration or fatigue points. The living quarters 4 are made of the same material as the upper hull 3, contributing to the overall strength of the platform as a structural member. The pipe yard... 7 and heavy cargo container 8 are located at the rear of the upper hull 3. A moon pool is located in the center of the upper hull 3. The derrick 6 is located above the moon pool, and the lower end of the derrick 6 is inserted into the upper hull 3. The living quarters 4, derrick 6, pipe yard 7 and heavy cargo container 8 are all located on the upper hull 3 inside the column 2. The remaining light equipment is arranged on the deck of the upper hull 3 above the column 2 and on the outer side, so as to ensure that there is a large vertical load in the middle area of ​​the entire platform. After being transferred to the column 2, it forms a pretension that separates the column 2 from the lower hull 1.

[0038] In summary, this invention, by arranging the columns 2 at an angle and placing heavy-duty equipment within the deck area of ​​the upper hull 3 between the columns 2, while placing light-duty equipment within the deck area outside the columns 2, ensures that the structural self-weight load transmitted from the upper hull 3 is converted into a sufficiently large preload to resist the wave pressure that causes the lower floats to move closer together. Furthermore, the connection point between the columns 2 and the upper hull 3 is enlarged to ensure sufficient connection strength to resist the bending moment transmitted from the pressure between the lower floats 1 to the entire upper hull 3. Through this structural arrangement, only separation forces exist between the lower floats. The structure needs to be designed to withstand the pressure, and the compressive force can be borne by the float itself. Therefore, the cylindrical cross bracing used in conventional semi-submersible platforms to withstand tensile and compressive forces can be replaced with multiple connecting steel cables 5 to withstand only tensile forces. On the one hand, the steel cables 5 are not affected by the torsion caused by platform deformation and only bear axial tensile loads, so they will not be damaged when the entire platform is large or in extremely harsh sea conditions. On the other hand, since the cross section of the steel cables 5 is smaller, their drag and slamming performance are significantly better than those of the cylindrical cross bracing, thus providing better drag performance and improving the platform's speed.

[0039] Furthermore, extending the upper hull 3 beyond the column 2 increases the usable deck area. This also avoids excessive distance between the lower floats when the required platform size is large, thus preventing excessive wave loads and ensuring sufficient strength for the connecting steel cables 5. The enlarged section at the end of the column needs to have good strength. A transition section 24 is provided at the connection between the column 2 and the lower float 1, forming a smooth transition through a round-to-square connection. At the same time, there are smooth rounded chamfers around the middle of the column 2, further reducing the drag and structural stress of the entire column in the water. This can effectively improve the survivability of the semi-submersible platform in extreme sea conditions. Combined with the drag reduction of the streamlined hull shape of the lower float 1 and the thrust enhancement effect of the multiple propellers, the speed and stability of the entire platform are further improved.

[0040] In other embodiments, the upper hull can be extended not only laterally but also longitudinally to ensure that the upper hull has a sufficiently large deck area. The ends of the columns can also be enlarged longitudinally, and the outward tilt angle of the columns can be adjusted according to different actual designs.

[0041] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-speed semi-submersible platform suitable for high sea states, characterized in that, The system includes a lower float (1), a column (2), an upper hull (3), and a propeller. The upper hull (3) is horizontally arranged. There are multiple columns (2). The upper end of the column (2) is connected to the lower surface of the upper hull (3), and the lower end of the column (2) is inclined to the outside of the upper hull (3). The columns (2) are symmetrically arranged. An inner enlarged structure (21) is provided at the connection between the inner side of the column (2) and the upper hull (3). An outer enlarged structure (22) is provided at the connection between the outer side of the column (2) and the upper hull (3). There are two lower floats (1), which are symmetrically arranged below the upper hull (3). The lower floats (1) are connected to the lower end of the column (2). A connecting steel cable (5) is connected between the lower floats (1). The connecting steel cable (5) is located on the lower floats (1) within the coverage area of ​​the column (2). The propeller is located on the lower floats (1). The upper hull (3) extends outward from both sides of the column (2); The lower floating body (1) has a streamlined hull structure, with a bulbous bow at the front, and the bow deck of the lower floating body (1) is raised upwards; The inner enlarged structure (21) is a large-radius rounded shape; The column (2) includes a column support section (20), a column middle section (25), a transition section (24), and a column square section (23). The upper end of the column support section (20) is connected to the upper hull (3). The column middle section (25) is connected to the lower end of the column support section (20). The lower end of the column square section (23) is connected to the lower float (1). The column square section (23) has the same width as the upper surface of the lower float (1). The transition section (24) is connected between the column middle section (25) and the column square section (23). The middle section (25) of the column has rounded corners on its side, and the rounded corners on the side facing the bow are larger than the rounded corners on the side facing the stern. The column (2) is tilted to ensure that the structural load transmitted from the upper hull (3) is converted into a sufficiently large pretension to resist the squeezing force generated by the waves that causes the lower floating bodies (1) to move closer together. Multiple connecting steel cables (5) are used to connect the lower floating bodies (1) on both sides to ensure that the column (2) and the lower floating body (1) will not separate or deform excessively under the action of the separation force generated by the waves and the pretension load transmitted from the upper hull (3), thus maintaining the overall performance of the platform. At the same time, the connecting steel cables (5) are set on the lower floating bodies (1) within the coverage area of ​​the column (2) to avoid the additional bending moment caused by the deviation of the force application point of the connecting steel cables (5) and the column (2) on the lower floating body (1).

2. The high-speed semi-submersible platform suitable for high sea states according to claim 1, characterized in that, The column (2) is a double-layer shell with an inner wall (27) inside and an outer plate (26) outside. A horizontal partition (28) or a horizontal bulkhead is provided between the outer plate (26) and the inner wall (27).

3. The high-speed semi-submersible platform suitable for high sea states according to claim 1, characterized in that, The tilt angle of the column (2) shall not be less than 5°.

4. The high-speed semi-submersible platform suitable for high sea states according to claim 1, characterized in that, The lower float (1) is provided with multiple partition walls (102) to divide the lower float (1) into multiple ballast tanks, and the lower float (1) on both sides of the column (2) is provided with support walls (101).

5. The high-speed semi-submersible platform suitable for high sea states according to claim 1, characterized in that, The thrusters include a full-rotation thruster (9) and a retractable thruster (10). Multiple full-rotation thrusters (9) and retractable thrusters (10) are provided. The full-rotation thruster (9) is located at the tail of the lower float (1) and at the rear end of the column (2) closest to the tail of the lower float (1). The full-rotation thruster (9) is provided with one full-rotation thruster (91) with a flow guide and one full-rotation thruster (92) without a flow guide on each side of the lower float (1). The retractable thruster (10) is located at the bow of the lower float (1) and at the front end of the column (2) closest to the bow of the lower float (1).

6. The high-speed semi-submersible platform suitable for high sea states according to claim 1, characterized in that, The upper hull (3) is a rectangular box, and its interior is divided into multiple compartments by transverse and longitudinal bulkheads. The upper hull (3) is equipped with a living quarters (4), a pipe yard (7) and a heavy cargo container (8). The living quarters (4) are located at the front end of the upper hull (3), and its two sides do not extend beyond the vertical plane outside the column (2). An elbow plate is provided at the connection between the lower end of the living quarters (4) and the upper hull (3). The pipe yard (7) and the heavy cargo container (8) are located at the rear end of the upper hull (3). A moon pool is provided in the center of the upper hull (3). A derrick (6) is provided above the moon pool, and the lower end of the derrick (6) is inserted into the upper hull (3). The living quarters (4), the derrick (6), the pipe yard (7) and the heavy cargo container (8) are all located in the area of ​​the upper hull (3) inside the column (2).

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