Semi-submersible multi-purpose transport and disassembly vessel

Abstract

The present invention discloses a semi-submersible multifunctional transport and disassembly vessel, which comprises a narrow bow extension, a wide midship bow, and a catamaran stern. The stern is connected to one end of the midship bow, and the other end of the midship bow is connected to a bow extension that is narrow relative to the midship bow. The stern is a catamaran structure, and there is an empty slot area between the two hulls of the stern. The beneficial effect of the present invention is that it can resolve the contradiction between transportation and disassembly suitability, while taking into account economic cost considerations. The semi-submersible multifunctional transport and disassembly vessel can functionally meet the requirements of transporting extra-long and extra-wide large equipment such as floating production storage and offloading vessels, and can also engage in special operations such as floating installation and offshore platform disassembly. The ship type has a large target market, a wide range of suitable cargoes, and a strong ability to resist market risks.

Description

Technical Field

[0001] The present invention relates to the technical field of semi-submersible vessels, in particular to a semi-submersible multifunctional transport and disassembly vessel with installation and disassembly functions. Background Art

[0002] Large four-island semi-submersible vessels are specialized seagoing vessels designed to transport extremely long and heavy equipment, such as floating production storage and offloading vessels (FPSOs), offshore oil rigs, large ships, and submarines. During operation, these vessels maintain a controlled ballast level to submerge the main deck 10-30 meters below the surface, leaving only the forecastle and pontoons at the four corners visible. Once the cargo is towed above the loading deck, large air compressors or load-adjusting pumps are activated to drain the ballast water from the semi-submersible, allowing the vessel and the cargo on deck to surface. Once secured, the cargo can be transported to the designated destination. Existing large four-island semi-submersible vessels typically have a deck width exceeding 60 meters to accommodate the extra-wide structures required for loading FPSOs. While this wide width meets the requirements for transporting extra-wide structures, it also limits their market share for offshore float-over installation (which typically requires a width of less than 45 meters) and dismantling.

[0003] A catamaran dismantling vessel is a large, specialized vessel used for offshore dismantling and installation. It can be composed of two separate vessels with temporary reinforcements and connecting structures, or it can be a single, partially consolidated catamaran. A characteristic of a catamaran dismantling vessel is the large, open space between the hulls for dismantling and installation operations. However, the disadvantages of large, permanent catamaran dismantling vessels include high equipment costs, strong dependence on the dismantling market, and low resilience to market risks. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the aforementioned existing vessel types by providing a semi-submersible, multifunctional transport and disassembly vessel that not only resolves the conflict between transport and disassembly suitability, but also balances economic considerations. This semi-submersible, multifunctional transport and disassembly vessel is capable of transporting large, ultra-long and ultra-wide equipment, such as floating production storage and offloading vessels, while also performing specialized operations such as float-over installation and offshore platform disassembly. It offers advantages such as a large target market, a wide range of cargo suitability, and strong resilience to market risks.

[0005] In order to achieve the above-mentioned purpose, the present invention provides the following technical solution: a semi-submersible multifunctional transport and disassembly ship, comprising a bow part amidships and a stern part, wherein the stern part is connected to one end of the bow part amidships, and the stern part is a catamaran structure, and an empty slot area is provided between the two hulls for disassembly and assembly operations to meet different cargo transportation needs.

[0006] The other end of the midship bow is connected to a bow extension body which is narrow relative to the midship bow. The bow extension body can enter the loading platform for floating assembly and disassembly operations, which is beneficial to loading and unloading operations.

[0007] The present invention is an organic combination of a four-floating-island submerged buoyancy layout design with three modular designs: a catamaran stern, a wide-body amidships bow, and a narrow-body bow extension. This satisfies the contradiction between the main dimension requirements of the ship for different operational functions. While being able to transport extra-long and extra-wide large equipment such as floating production storage and offloading vessels, the narrow-body bow can also be used for floating assembly and disassembly operations, and the stern catamaran structure can be used for special operations such as offshore platform assembly and disassembly.

[0008] A control room is arranged at the front position of the starboard side of the midship bow, and the control room is arranged on the outer floating support structure of the midship bow deck, which can effectively expand the cargo space of the midship bow deck.

[0009] At least one movable pontoon is provided at the bow amidships of the ship. At least two pontoons are provided at the stern of the ship, and the pontoons are respectively provided at the side edges of the hull deck on both sides of the empty tank area.

[0010] Two pontoons are installed on the side edges of the deck of each hull at the stern. In this way, five movable pontoons can be installed on the open deck. The pontoons can be moved to any position on the open deck and can be fixed to the hull deck by welding or anchoring.

[0011] The bow sealing plate of the bow extension body is a flat structure, which is conducive to abutting against the operating dock. The cargo to be loaded can be loaded onto the ship deck by sliding, and the loading is extremely simple.

[0012] The stern sealing plate at the stern of the ship is a flat structure, which is conducive to abutting against the operating dock. The cargo to be loaded can be loaded onto the ship deck in a sliding manner, and the loading is extremely simple.

[0013] The buoyancy box consists of a lower buoyancy module and an upper mooring module, and the lower buoyancy module and the upper mooring module are connected by bolts.

[0014] A simple control room is provided in the upper mooring module for observation and control of berthing and unberthing operations.

[0015] The upper mooring module is equipped with a mooring winch, a bollard, a Panama chock, a four-post bollard, a double-post bollard, a buoyancy lug, and an assembly bolt superstructure. The lower buoyancy module provides buoyancy during submersion. Its bottom is welded or riveted to the main deck, and its upper portion is riveted to the upper mooring module with assembly bolts. A power cable channel can be provided within the lower buoyancy module to connect power and signals to the main hull.

[0016] The pontoon can be connected to the power cable channel in the main hull pedestrian channel through the power cable junction box arranged therein, so that the main hull can supply power to the upper mooring module and control room on the pontoon and realize signal communication.

[0017] A streamlined transition outer plate is provided in the transition area of ​​the bow amidships to reduce sailing resistance.

[0018] The transition area is provided with internal transverse strong girders, longitudinal frames, internal longitudinal strong girders, internal longitudinal bulkheads and internal tank decks.

[0019] An arc-shaped transition plate is provided in the inner groove transition area between the bow and the stern of the ship, and the arc-shaped transition plate is smoothly connected to the arc-shaped transition outer plate of the stern to reduce structural stress concentration.

[0020] A streamlined transition outer plate is provided on the control chamber outer floating support structure.

[0021] The empty slot area can be filled with a detachable deck filling structure so that the aft deck and the main deck at the bow amidships form a complete whole, thereby increasing the effective deck area and being more conducive to cargo arrangement and load bearing.

[0022] The detachable deck filling structure may be an assembled filling structure or an integral filling structure.

[0023] The assembled filling structure is composed of a plurality of filling-type span beam units, span beam unit panels and span beam unit webs. The span beam unit panels are welded to form a whole through the filling-type span beam unit internal reinforcement components and the span beam unit webs.

[0024] The bottom of the web of the span beam unit is designed to be arc-shaped. Depending on the different span beam bearing capacity designs, the arc radius is between 20-200 meters. When the unit is subjected to vertical loads, the stress flow inside the structure can be smoother.

[0025] The integral filling structure of the hull in the empty slot area at the stern is prefabricated as a whole before filling, and is connected to the outer plate of the inner slot at the stern by welding or riveting through connecting and fixing components.

[0026] A buffer positioning module is provided on the side wall of the hull in the empty slot area of ​​the catamaran stern, and the buffer positioning module includes a fender, a transverse fender and a longitudinal fender.

[0027] The transverse fender includes a transverse fender base, a transverse fender and a guide fender. The transverse fender base is welded and installed in the inner groove of the hull side wall. The transverse fender is fixed to the transverse surface of the transverse fender base. The guide fenders are respectively fixed on both sides of the transverse fender base. The transverse fender includes a transverse fender panel, a transverse fender elastomer and a transverse fender base. The transverse fender base is fixed to the transverse fender base by welding or riveting, the transverse fender panel is fixed to the transverse fender base, and the transverse fender elastomer is arranged between the transverse fender panel and the transverse fender base.

[0028] The semi-submersible multifunctional transport and disassembly vessel of the present invention consists of a catamaran stern, a wide-body bow amidships, and a narrow-body bow extension. The structure above the main deck adopts a four-island diving buoyancy layout; its control room is located in the front position of the starboard side of the bow amidships, and the deck is equipped with 5 movable pontoons. During diving operations, the pontoons are fixed to the main deck by welding or anchoring, and are respectively arranged on the port side of the front of the bow amidships of the main deck, the port side of the stern, and the starboard side, forming a four-island buoyancy layout to meet the requirements of diving stability and reserve buoyancy. The hull adopts a wide-body design and a ship width designed to meet the transportation of large floating production storage and offloading vessels; the bow extension is a narrow-body design, with the design standard of meeting the requirements of floating installation functions; the stern adopts a catamaran design, with the design goal of meeting the requirements of offshore disassembly and assembly operations. The bow extension features a streamlined design below the load line to reduce resistance. The bow extension's bottom plating features a forward-rake design, enhancing the vessel's speed under lightly loaded conditions. The bow extension and the stern area near the main deck utilize bow and stern closures. This allows for longitudinal berthing at the dock, in addition to side berthing, using both bow and stern berthing methods to support loading operations. The forward-rake design of the bow extension's lower line reduces the required water depth for docking amidships. The movable pontoons are a split-piece design, with a buoyancy structure at the bottom and a mooring module at the top, secured by welding or riveting. These two components can be used together or separately, depending on operating conditions and needs. A simple control room is located on the port side of the bow, above the buoyancy structure and below the mooring module, for both lookout and portside maneuvering. The bottom buoyancy structure of the movable pontoon at the stern is designed based on the design of the submerged pontoon and in accordance with the structural design requirements of the crane base, and can subsequently be used as a crane base. The pedestrian walkway within the main hull is arranged longitudinally along the outer side of the hull, with three transverse channels located: one at the bow extension connecting the two sides; one at the forward position of the bow amidships, connecting from the bottom of the control room to the bottom of the movable pontoon on the port side; and one at the aft position of the bow amidships, connecting the left and right stern bodies. Several cable channels leading to the main deck are provided within the pedestrian walkway to support the movable pontoon to draw power from the main hull and establish signal connection with the main hull when it moves within the outer edge of the deck.

[0029] In order to meet the needs of loading cargo in the midship bow loading area, the transition connection between the narrow-body bow extension and the midship bow has been structurally strengthened to enhance the structural load caused by the concentrated cargo weight of the bow extension and the sudden change of hydrodynamic load caused by the change of the geometric shape of the bow extension and the midship bow.

[0030] To meet the cargo capacity requirements of the aft loading area and the needs of the catamaran's stern assembly and disassembly operations, the connection between the catamaran's stern and the amidships bow has been structurally reinforced to address stress concentration in the aft transition section caused by factors such as the concentrated and eccentric weight of the aft cargo and the sudden change in hydrodynamic loads caused by the geometric changes between the catamaran's stern and the amidships bow. The connection between the control room and the amidships bow has also been structurally reinforced to address the hull structural loads during transportation caused by the control room's heavy weight and high center of gravity.

[0031] Compared to existing technologies, the present invention offers the advantage of a multifunctional transport and dismantling vessel that resolves the conflict between transport and dismantling suitability while also addressing cost-effectiveness. This semi-submersible, multifunctional transport and dismantling vessel is capable of transporting ultra-long and ultra-wide large equipment, such as floating production storage and offloading vessels, while also performing specialized operations such as float-over installation and offshore platform dismantling. This vessel type has a large target market, a wide range of cargo suitability, and strong resilience to market risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A perspective view of a semi-submersible multifunctional transport and disassembly vessel according to the present invention;

[0033] Figure 2 This is a three-dimensional drawing of the bow extension line;

[0034] Figure 3 This is the side view of the bow extension;

[0035] Figure 4 This is a side view of the bow extension body during docking operation;

[0036] Figure 5 This is a side view of the stern of the ship docking;

[0037] Figure 6 It is a three-dimensional assembly drawing of the movable pontoon;

[0038] Figure 7 A perspective view of the upper mooring module of the movable pontoon;

[0039] Figure 8 A top-down structural diagram of the pedestrian passage and the main hull power cable passage;

[0040] Figure 9 This is a schematic diagram of the cable connection structure between the pontoon and the pedestrian passage;

[0041] Figure 10 This is a schematic diagram of the connection reinforcement of the transition area between the bow extension and the midship bow;

[0042] Figure 11 This is a schematic diagram of the transition connection reinforcement between the stern and the bow;

[0043] Figure 12 Schematic diagram of the support structure for controlling outdoor drift;

[0044] Figure 13 This is a schematic diagram of the assembly-type filling structure in the empty slot area;

[0045] Figure 14 This is a schematic diagram of the overall filling structure of the empty slot area;

[0046] Figure 15 This is a cross-sectional view of a common rib of the hull side structure;

[0047] Figure 16 This is a cross-sectional view of the ribs of the hull side structure;

[0048] Figure 17 The following is a schematic diagram of the fender system layout;

[0049] Figure 18 Schematic diagram of the three-dimensional structure of the transverse fender;

[0050] Figure 19 A three-dimensional structural diagram of the demolition site for demolition work;

[0051] Figure 20 A perspective view of a large floating production storage and offloading vessel;

[0052] Figure 21 A perspective view of a carrying column platform;

[0053] Figure 22 A perspective view of a semi-submersible production platform being loaded;

[0054] Figure 23 A three-dimensional diagram showing the arrangement of the bow extension float-over and disassembly operations;

[0055] Figure 24 This is a diagram of the disassembly and assembly status of the tail catamaran float.

[0056] Among them, 1 is the bow extension, 2 is the bow amidships, 3 is the stern, 4 is the control room, 5 is the outer floating support structure of the control room, 6 is the movable pontoon, 7 is the bow sealing plate, 8 is the bottom outer plate of the bow extension, 9 is the lines on both sides of the bow extension, 10 is the operating dock, 11 is the cargo to be loaded, 12 is the support frame, 13 is the stern sealing plate, 14 is the lower buoyancy module, 15 is the upper mooring module, 16 is the simple control room, 17 is the mooring winch, 18 is the fairlead bollard, 19 is the Panama fairlead hole, 20 is the four-column fairlead bollard, 21 is the pontoon lifting lug, 22 is the double-column bollard, 23 is the assembly bolt, and 24 is the pontoon power cable through. 25 is a pedestrian passage, 26 is a main hull cable passage, 27 is a cable junction box, 28 is a main deck, 29 is a curved transition outer plate at the bow, 30 is an internal transverse strong girder, 31 is a longitudinal frame, 32 is an internal longitudinal strong girder, 33 is an internal longitudinal bulkhead, 34 is an internal tank deck, 35 is a curved transition plate, 36 is an internal strong rib plate, 37 is an internal rib, 38 is a curved transition outer plate at the tail, 39 is a transverse main girder, 40 is a streamlined transition outer plate, 41 is a hull side outer plate, 42 is a main deck at the bow, 43 is an assembled filling structure, 44 is a filling-type span beam unit, 45 is a span beam unit panel, 46 is a stern panel, 47 is the web of the span beam unit, 48 is the outer plate of the tail inner groove, 49 is the integral filling structure, 50 is the connecting and fixing component, 51 is the floating production storage and offloading vessel, 52 is the column platform, 53 is the semi-submersible production platform, 54 is the upper module for floating assembly and disassembly, 55 is the upper module support frame, 56 is the floating installation docking buffer device, 57 is the deck support arm, 58 is the jacket; 101 is the outer shell, 102 is the deck, 103 is the second deck, 104 is the double bottom, 105 is the longitudinal bulkhead, 106 is the box unit, 107 is the side longitudinal girder, 108 is the rib, 109 is the anti-roll bracket, 11 0 is the bracket, 111 is the curved bracket, 112 is the solid web, 113 is the horizontal stiffener, 114 is the vertical stiffener, 115 is the web frame, 116 is the longitudinal bone, 117 is the beam, 118 is the rib, 119 is the deck girder, 120 is the side longitudinal fender structure, 121 is the between-deck longitudinal girder, 122 is the inner bottom plating, 221 is the adaptable removal support arm, 224 is the fender, 222 is the transverse fender, 223 is the longitudinal fender, 225 is the transverse fender panel, 226 is the transverse fender elastic body, 227 is the transverse fender base, 228 is the transverse fender base, 229 is the guide fender base, and 230 is the guide fender. DETAILED DESCRIPTION

[0057] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0058] The bow extension 1 of the present invention features an overall streamlined design below the load line to reduce sailing resistance. The bow extension's bottom plating features a forward-rake design, reducing the required water depth for docking and improving navigation speed under light load conditions. The bow extension 1 and stern 3, near the main deck, utilize flat-plate bow and stern closures 7 and 13 to support longitudinal docking operations.

[0059] The present invention adopts a movable pontoon 6 design, and the position of the pontoon can be adjusted along the entire outer edge of the deck as needed; the movable pontoon 6 adopts a split design, the bottom of which is a buoyancy structure that can be used as a crane base; the top is an upper mooring module, which has a simple control room inside for operating the ship in the area outside the control room.

[0060] The design of the pedestrian passage corresponds to the possible moving position of the movable pontoon 6 on the main deck, and is equipped with several cable channels leading to the main deck, which support the movable pontoon 6 to obtain power from the main hull and conduct signal docking with the main hull when moving within the outer edge of the deck.

[0061] To cope with the intense structural loads imposed by various operating conditions, key connections have been reinforced. These include the connection between the bow extension 1 and the midship bow 2, the connection between the catamaran stern 3 and the midship bow 2, and the connection between the control room and the midship bow 2. These reinforcements effectively enhance the structural capacity of the hull and support the realization of the overall structural layout described in this invention.

[0062] In the empty slot area between the catamaran structures at the stern 2, two detachable deck filling structures, an assembled filling structure and an integral filling structure, are provided, thereby expanding the operational capacity of the semi-submersible transport vessel.

[0063] Semi-submersible multi-purpose transport and disassembly vessel, such as Figure 1As shown, it includes a narrow bow extension 1, a wide midship bow 2, and a catamaran stern 3. The stern 3 is connected to one end of the midship bow 2. The stern 3 and the midship bow 2 can be detachably connected, which increases the flexibility of use of the midship bow 2 and stern 3. The other end of the midship bow 2 is connected to the bow extension 1, which is narrow relative to the midship bow 2. This forms a combination in which the bow extension 1 and stern 3 are detachably connected to the front and rear of the midship bow 2, respectively. The stern 3 is a catamaran structure and can be composed of two floating island-type submersible hulls. An empty slot area is provided between the two hulls of the stern 3 for disassembly and assembly operations to meet different cargo transportation needs. A control room 4 is provided at the front starboard side of the bow 2 amidships. The control room 4 is provided on the outer buoyancy support structure 5 of the deck of the bow 2 amidships, which can effectively expand the deck cargo space of the bow 2 amidships. At least one movable pontoon 6 is provided at the bow 2 amidships. At least two pontoons 6 are provided at the stern 3, and the pontoons 6 are respectively provided at the side edges of the hull deck on both sides of the empty slot area. Preferably, two pontoons 6 are provided at the side edges of the deck of each hull at the stern 3. A movable and detachable structure is provided between the pontoons 6 and the deck, so that five movable pontoons 6 can be provided on the open deck. The pontoons 6 are movably and detachably fixed at any position of the open deck, and can be fixed to the hull deck by welding or anchoring. The five movable pontoons 6 on the hull deck form a four-island submerged buoyancy layout with the control room 4. During submersible operations, the movable pontoons 6 are arranged on the port side of the bow 2, the port side of the stern, and the starboard side of the main deck, respectively, to meet the requirements for submersible stability and reserve buoyancy. The present invention organically combines a four-floating-island submersible layout with three modular designs: a narrow-body bow extension 1, a wide-body midship bow 2, and a catamaran stern 3. This effectively resolves the conflicting requirements of the vessel's main dimensions for different operational functions. While enabling the transport of extra-long and extra-wide large equipment such as floating production storage and offloading vessels, the narrow-body bow can also be used for float-over and assembly operations, and the stern catamaran structure can be used for specialized operations such as offshore platform assembly and disassembly.

[0064] The bow extension body 1 is as follows Figure 2 and Figure 3 As shown, the bow closure plate 7 is provided. This flat structure allows the bow extension 1 to easily dock at a pier. The bottom outer plate 8 of the bow extension 1 is tilted forward, with a tilt range of 2-4 meters. This improves the ship's navigation speed under light load conditions and reduces the required water depth when the bow extension 1 docks. The contour lines 9 on both sides of the bow extension 1 adopt a wave-split streamline design to reduce navigation resistance.

[0065] When the bow extension 1 is loading at the dock, Figure 4As shown, the bow cover plate 7 of the bow extension body 1 can be close to the operating dock 10, and the cargo 11 to be loaded can be moved onto the deck of the bow extension body 1 through a slide or a cargo support frame 12, making it extremely easy to load the cargo 11 to be loaded.

[0066] The stern 3 is provided with a tail sealing plate 13, which is a flat structure, so as to facilitate the loading of the cargo 11 to be loaded on the stern 3. When the stern 3 is loaded at the dock, Figure 5 As shown, the stern 3 is a stern cover plate 13 that can approach the operating dock 10, and the cargo 11 to be loaded can be moved onto the deck of the stern 3 or the empty slot area through a slide or a cargo support frame 12, so loading the cargo 11 to be loaded is also extremely simple.

[0067] When the bow extension 1, stern 3 and midship bow 2 of the semi-submersible multifunctional transport and disassembly ship of the present invention are docked for operation, thanks to the flat-plate design structure of the bow sealing plate 7 and the stern sealing plate 13, during the dock loading operation, in addition to traditional lateral loading, the bow extension 1 can also be docked for longitudinal loading and the stern can be docked for longitudinal loading.

[0068] The buoyancy tank 6 is as follows Figure 6 and Figure 7 As shown, it consists of a lower buoyancy module 14 and an upper mooring module 15, and the lower buoyancy module 14 and the upper mooring module 15 can be fixedly connected by bolts. The four upper corners of the lower buoyancy module 14 are provided with buoyancy box lugs 21, and a power cable channel 24 is provided on the upper part. Among them, a simple control room 16 is provided in the upper mooring module 15, and the simple control room 16 is provided with several observation windows for observing the environment so as to adjust the control parameters according to the actual environmental conditions. The upper mooring module 15 is also provided with a mooring winch 17, a bollard 18, a Panama bollard hole 19, a four-column bollard 20, a buoyancy box lug 21 and an assembly bolt upper structure 22. The lower buoyancy module 14 provides buoyancy during the diving process, and is fixedly connected to the main deck by bottom welding or riveting. The lower buoyancy module 14 includes an assembly bolt lower structure 23 and a power cable channel 24. The assembly bolt lower structure 23 is connected and fixed to the upper mooring module 15 by bolts. The power cable channel 24 is connected to a simple control room 16 provided in the upper mooring module 15, so that the main hull and the upper mooring module 15 are connected in terms of power and signals.

[0069] like Figure 8 and Figure 9As shown, a vertical power cable channel 26 leading to the main deck is provided in the pedestrian passage of the main hull. The vertical power cable channel 26 is connected to the power cable channel 24 of the pontoon 6. The design of the main hull connecting with the pontoon 6 through the power cable channel 26 takes into account the realization of power supply and signal connection for the pontoon 6 at the main possible position on the main deck 28 during diving operations. The pedestrian passage 25 is connected to the vertical power cable channel 26 to facilitate power connection operations and maintenance operations. The pontoon 6 is connected to the cables in the pedestrian passage 25. The vertical power cable channel 26 in the pedestrian passage 25 is connected to the power cable channel 24 in the cable junction box 27 of the pontoon 6, which is used to supply power to the upper mooring module 15 and the simple control room 16 of the pontoon 6 and realize signal connection.

[0070] like Figure 10 As shown, the transition area of ​​the midship bow 2 is provided with a curved transition outer plating 29 to reduce navigation resistance. This transition area is reinforced with internal transverse stiffeners 30, longitudinal ribs 31, internal longitudinal stiffeners 32, internal longitudinal bulkheads 33, and an internal tank deck 34. The internal transverse stiffeners 30 are primary transverse reinforcements, cross-connected with the outer plating, deck, longitudinal bulkheads, and internal longitudinal stiffeners 32 to form a reinforced frame structure supporting the deck. The internal longitudinal bulkheads 33 are extensions of the midship bulkheads, dividing the cabins and serving as the primary longitudinal reinforcements, cross-connected with the internal transverse stiffeners 30 to form a reinforced frame structure. The internal longitudinal stiffeners 32 are primary longitudinal reinforcements, arranged between the two transverse stiffeners and directly connected to the main deck, enhancing the deck's load-bearing capacity. The longitudinal stiffeners 31 are extensions of the midship longitudinals, arranged between the two internal transverse stiffeners and vertically atop the internal stiffeners, serving as longitudinal reinforcements.

[0071] like Figure 11As shown, a curved transition plate 35 is installed in the inner channel transition area between the bow section 2 and the stern section 3. This curved transition plate 35 forms a smooth transition connection with the curved transition outer plating 38 of the midship section 3 to reduce structural stress concentration. The curved transition plates 35 are arranged vertically from the main deck to the bottom plating at the strong structural locations. Internal ribs 36 and internal ribs 37 are installed within the inner channel transition area for additional reinforcement. The internal ribs 36 are the primary transverse reinforcement members in the inner channel transition area. They are arranged transversely and vertically, directly connected to the outer plating and the curved transition plates 35, supporting the curved transition plates 35 and improving local strength. A manhole is provided in the center of the internal ribs 36 for easy access for maintenance and inspection. The internal ribs 37 are arranged transversely and vertically, serving as transverse reinforcement members in the transition area. They are directly connected to the outer plating and the curved transition plates 35, improving local strength. Longitudinal ribs 31 are longitudinal reinforcement members, arranged vertically and extending from the longitudinals, terminating at the edges of the curved transition plates 35. Internal ribs 36 and curved transition plates 35 are arranged on the deck, second deck, inner bottom plate, bottom plate, etc. to improve local strength.

[0072] like Figure 12 As shown, a streamlined transition outer plate 40 is provided on the outer buoyancy support structure 5 of the control room. Transverse main girders 39 are locally provided in the transverse direction of the streamlined transition outer plate 40 for reinforcement. Transverse strong girders 30 are provided inside the main hull to improve the structural strength. The transverse main girders 39 and the transverse strong girders 30 are butted together to form a transverse integral reinforcement structure. The longitudinally dense longitudinal frame 31 is a longitudinal reinforcement member, which is arranged between the two transverse main girders 39 and is located vertically at the top position to improve local strength. The transverse main girders 39, the longitudinal frame 31, the outward-drifting streamlined transition outer plate 40 and the hull side outer plate 41 form an integral load-bearing frame structure to cope with the local structural load of the hull caused by factors such as the heavy weight and high center of gravity of the control room 4.

[0073] like Figure 13 As shown, the hollow area between the two hulls of the stern section 3 is provided with an assembled filling structure 43. This assembled filling structure 43 comprises several filling-type span beam units 44, span beam unit panels 45, and span beam unit webs 46. The span beam unit panels 45 are welded to the span beam unit webs 46 via internal reinforcement members 47 of the filling-type span beam units 44 to form a single unit. After being prefabricated onshore, the unit is connected to the hull of the catamaran stern section 3 by welding or anchoring. The bottom of the span beam unit webs 46 is designed to be curved, with a radius ranging from 20 to 200 meters depending on the span beam load capacity design. This ensures smoother stress flow within the structure when the unit is subjected to vertical loads. The span beam unit webs 46 are transversely aligned with the internal transverse girders 30 of the catamaran stern section 3, allowing for effective transfer of forces to the hull's strength structure.

[0074] like Figure 14As shown, the integral filling structure 49 in the empty slot area of ​​the stern section 3 is prefabricated in its entirety prior to filling and connected to the inner slot outer plate 48 of the stern section 2 via connecting and fixing members 50 by welding or riveting. Similar to the assembled filling structure 43, the transverse and longitudinal stiffening structures within the integral filling structure 49 are positioned in an integrated manner with the main hull transverse stiffening girders 30 and longitudinal stiffening girders 32, ensuring that forces acting on the filling structure are effectively transferred to the hull stiffening structure.

[0075] When a semi-submersible multi-purpose transport and disassembly vessel operates as a semi-submersible transport vessel for a long period of time, the empty space between the catamaran structures at the stern can be filled with a removable deck infill structure, allowing the stern deck to form a complete whole with the main deck at the bow amidships. This increases the effective deck area and facilitates cargo layout and load bearing. The assembled infill structure, primarily intended to fill deck space, has a relatively low deck load capacity, but the individual pieces are lightweight and require minimal construction. The assembled infill structure is designed as an open structure without underwater buoyancy. The integral infill structure is fast to construct and can be designed as a closed structure as needed to provide buoyancy and increase load-bearing capacity. The design of the semi-submersible multi-purpose transport and disassembly vessel reserves a ballast system interface between the stern catamaran section and the ballast tanks of the integral infill structure.

[0076] In order to increase the overall load-bearing capacity, improve the side load-bearing capacity, save construction time and reduce costs, the hull side structure of the present invention is as follows: Figure 15 and Figure 16The vessel comprises a hull shell 101, a main deck 102, a second deck 103, a double bottom 104, longitudinal bulkheads 105, and box-type units 106. The double bottom 104 is connected to the bottom of the hull shell 101. The main deck 102 is located above the hull shell 101, and the second deck 103 is located below the main deck 102. Inside the cabin, longitudinal bulkheads 105 are located between the double bottom 104 and the second deck 103. The box-type units 106 are connected to the top of the hull shell 101. Crossbeams 117 are located at the upper and lower portions of the box-type units 106, connecting them to the main deck 102 and second deck 103, respectively. Ribs 118 are located on the left and right sides of the two crossbeams 117 for connection and support. A manhole is provided on the longitudinal girder 121 between decks near the midship to facilitate access for inspection, repair, and maintenance. Side ribs 108 are installed inside the hull shell 101 to increase strength. These side ribs 108 are connected to the lower crossbeams 117 of the box-type units 106, and their bottoms are connected to the double bottom 104. The spacing between adjacent side ribs is between 600 and 800 mm. The hull shell 101 is equipped with several horizontally arranged side girders 107 from top to bottom. The ends of these side girders 107 extend to the bow and stern, respectively, to enhance overall longitudinal strength and support the vertically arranged side ribs 108. A horizontally arranged side girders 107 is installed between every three side ribs. The ends of these side girders 107 are connected to the watertight bulkheads and extend toward the bow and stern, respectively, to enhance overall longitudinal strength. The side ribs 108 are cross-connected to the side girders 107 and reinforced by two upper and lower anti-roll brackets 109. A bracket 110 is provided at the connection between the upper end of the side rib 108 and the box-type unit 106 to strengthen the connection, and an irregular triangular bracket 111 is provided at the connection between the lower end and the double bottom 104 to smooth the transition, which is beneficial to alleviate the load transfer to the double bottom 104, improve the strength, and also strengthen the support of the deck and the side.

[0077] The box-shaped unit 106 is internally fitted with a solid web 112 connected to all four sides. Horizontal stiffeners 113 and vertical stiffeners 114 are positioned at corresponding longitudinals 116 to enhance load-bearing capacity and connect to cargo racks to withstand external forces. Below the box-shaped unit 106, between the second deck 103 and the double bottom 104, vertically arranged stiffeners 115 are installed. The upper ends of these stiffeners 115 extend two to three longitudinal spacings at their connection to the box-shaped unit 106, while their lower ends curve over at the bilge and connect to the bottom structure. Brackets 118 are arranged horizontally and longitudinally at their connection to the side girder 107, reinforcing the connection and preventing tipping. Longitudinal side fenders 120 are installed longitudinally on the outer shell 101 between the deck 102 and the second deck 103, and between the second deck 103 and the inner bottom plating 122, respectively, to protect the on-site structure. Three common rib sections are set between the two strong rib position sections. The structures are interconnected and supported to ensure sufficient structural strength to meet loading requirements.

[0078] Most semi-submersible vessels and self-propelled barges have deck beams between 2 and 3.6 meters. The semi-submersible multi-purpose transport and disassembly vessel has beams spaced 2.4 meters apart, and the longitudinals 116 are typically spaced about 800 millimeters apart. The distance between the main deck 102 and the second deck 103 is typically between 2 and 3 meters. A row of deck girders 119, running from bow to stern near the side plating, is installed between the main and second decks 102, 103 to enhance the overall longitudinal strength of the hull. These deck girders 119 are equipped with standard-sized manholes for easy access for inspection, repair, and maintenance. Together, these deck girders 119, the side plating, the main deck 102, and the second deck 103 form a box-shaped structure. This structure is reinforced internally with beams 117, ribs 118, longitudinals 116, and stiffeners, thereby increasing the side deck's load-bearing capacity. Continuing down the box structure, side frames are installed between the second deck 103 and the inner bottom plating 122, spaced approximately 800 mm apart. Horizontally arranged side girders 107 are placed every three girders 108. The side girders 107 are connected to the watertight bulkheads at both ends and extend forward and aft, contributing to the overall longitudinal strength. The intersections between the side frames and the side girders 107 are reinforced with anti-roll brackets. This structure features three to four standard girders arranged longitudinally between every two strong girders, creating a distinct hierarchy of strong and weak girders to ensure sufficient structural strength to meet operational requirements. A box-shaped structure composed of longitudinals, beams, girders, and girders is installed between the standard girders and the second deck, enhancing the local strength and torsional resistance of the ship's deck side. Furthermore, a hybrid skeletal structure is employed between the second deck and the inner bottom plating, reducing the spacing between girders and increasing the number of girders. Side girders are also arranged from top to bottom. The above structure has the advantages of increasing the overall load-bearing capacity and improving the side load-bearing capacity; the longitudinal fender plays a role in protecting the side structure.

[0079] In order to meet the requirements of the demolition operation, the density of the longitudinal and transverse reinforcement structures inside the main deck of the catamaran stern 3 is designed to be distributed. The longitudinal reinforcement structure includes transverse bulkheads and longitudinal bulkheads. The transverse bulkheads and longitudinal bulkheads form a vertical partition structure when the compartments are separated by walls. On the basis of the original longitudinal ribs of the hull, a number of internal longitudinal strong girders are added next to the longitudinal ribs. In the transverse direction of the hull, a series of internal transverse strong girders are added next to the strong transverse beams of the hull. The density of the internal longitudinal strong girders and the internal transverse strong girders takes into account the law that the force on the hull gradually increases toward the bow 2 amidships during the demolition operation, so that the requirements of the demolition operation are comprehensively considered during the hull design stage.

[0080] The catamaran stern 3 is equipped with a docking module and a buffer positioning module. The docking module consists of an adaptive dismantling support arm 221 and a docking buffer cone. The base of the adaptive dismantling support arm 221 is fixed to the deck, and the docking buffer cone is fixed to the top of the adaptive dismantling support arm 221. The base of the adaptive dismantling support arm 221 can be welded to the deck. The length and width of the contact area between the base and the main deck are multiples of the span of the longitudinal structure and transverse reinforcement structure inside the stern of the hull, which can achieve the connection between its bottom outer frame and the hull's strong structure, ensuring that the weight load of the platform to be dismantled can be effectively transferred to the hull reinforcement structure. The adaptive dismantling support arm 221 is fixed to the edge of the deck in the empty slot area of ​​the catamaran stern 3. The docking buffer cone is welded and fixed to any position on the top of the adaptive dismantling support arm 221. Preferably, the docking buffer cone is fixed to the side of the top of the adaptive dismantling support arm 221 facing away from the empty slot area, which is conducive to improving strength and optimizing the load-bearing structure. An internal rubber elastomer is provided on the upper surface of the docking buffer cone to improve the contact buffering effect. The structural design of the adaptive dismantling support arm 221 allows the docking buffer cone to be fixed at any position on its top to support the weight of the upper module. By adjusting the position and direction of the adaptive dismantling support arm 221 on the main deck and the secondary position adjustment of the docking buffer cone on the top of the support arm, the position of the docking buffer cone can be flexibly arranged, thereby realizing a support point arrangement that is applicable to offshore platforms with different structural characteristics, respectively, and applicable to different upper modules to be dismantled. The movable pontoon 6 can be used as a counterweight during the dismantling operation, and can also be used to increase the pressure and water displacement capacity of the hull; it is placed in different positions and plays different roles. The movable pontoon 6 is placed on the main deck of the bow extension 1, which can increase the weight and adjustable ballast water volume of the bow 1, can reduce the stern draft, and increase the stern dismantling operation capacity in terms of pressure and water displacement capacity. The movable pontoon 6 is fixed to the outer side of the stern. When the total longitudinal strength of the hull is sufficient, it can reduce the hull torsional moment caused by the eccentricity of the module weight, and increase the stern dismantling operation capability in terms of structural strength. During the dismantling operation, the movable pontoon 6 is on the main deck of the bow 2 amidships. This arrangement of the movable pontoon 6 is a balanced arrangement that comprehensively improves the water discharge capacity and reduces the torsional moment of the stern structure. When the weight of the platform to be dismantled is small and the hull torsional moment caused by the eccentricity is small, the movable pontoon 6 can be arranged in the midship area where the deck area is wider. Figure 17-19As shown, a buffering and positioning module is installed on the sidewalls of the hollow area of ​​the catamaran stern 3. The buffering and positioning module includes a fender 224, a transverse fender 222, and a longitudinal fender 223. The fender 224, transverse fender 222, and longitudinal fender 223 are fixed to the sidewalls of the hollow area of ​​the hull. To minimize offshore construction and installation costs, the fenders 224 required for the dismantling operation are installed on the sidewalls of the hollow area of ​​the catamaran stern 3 to the greatest extent possible. The fender 224 is used to assist in entering and exiting the ship. It can be a rubber fender strip fixed to the lateral edge of the ship to provide lateral cushioning. It is used to provide lateral cushioning between the jacket and the stern sidewall during entry and exit. The transverse fender 222 is used to accurately locate the lateral relative position between the hull and the jacket after reaching the dismantling position and to buffer lateral relative movement between the two. The transverse fender 222 is fixed to the lateral edge of the hull and includes a transverse fender base 228, a transverse fender, and a guide fender 230. The transverse fender base 228 is welded to the inner groove of the hull sidewall, the transverse fender is fixed to the transverse surface of the transverse fender base 228, and the guide fenders 230 are fixed to both sides of the transverse fender base 228 to guide entry and exit of the ship. The transverse fender includes a transverse fender panel 225, a transverse fender elastic body 226, and a transverse fender base 227. The transverse fender base 227 is fixed to the transverse fender base 228 by welding or riveting. The transverse fender panel 225 is fixed to the transverse fender base 227, and the transverse fender elastic body 226 is disposed between the transverse fender panel 225 and the transverse fender base 227. The guide fender 230 serves as a guide and buffer for the jacket's main support legs during entry and exit. It is welded or riveted to the transverse fender base 228 via the entry and exit guide fender base 229. The longitudinal fender 223 is used to locate the longitudinal position between the hull and the jacket 223 and to buffer longitudinal relative motion between them after reaching the removal location. Its structure is identical to that of the transverse fender 222. The longitudinal fender 223 is installed at the longitudinal bottom of the hollow area of ​​the catamaran's stern 3, allowing contact with the transverse edges. During the removal operation, the catamaran stern (3) faces the jacket, starting approximately 500 meters from the jacket and moving under DP control to the front of the platform to be removed. Assisted by the buffer positioning module, it then slowly advances until it reaches the lower position of the upper module to be removed. The ballast water in the hull's ballast compartments and the movable pontoon (6) is then adjusted to adjust the stern draft and the height of the docking buffer cone, allowing it to dock with the upper module's docking buffer cone. The rubber elastic body inside the docking buffer cone acts as a buffer against vertical and horizontal impact loads during the docking process. After supporting the weight of the upper module to be removed, the stern draft is further reduced by adjusting the ballast, achieving complete separation of the jacket at the cut point.At the initial stage of separation, the pre-compressed rubber body 232 set inside the separation buffer will pop out and act on the upper support surface of the separation buffer receptor to cushion the impact load generated when the upper and lower bodies of the jacket are separated. After reaching the designed gap, the semi-submersible multi-functional transport and disassembly vessel slowly sails away from the jacket under DP control and with the assistance of fenders. After the stern is about 500 meters away from the jacket, the disassembly of the upper module is completed. The above structure utilizes the structural characteristics of the semi-submersible multi-functional transport and disassembly vessel itself. The required auxiliary tooling is light in weight, highly versatile, and the deck preparation is simple and flexible. The offshore construction preparation of this operation method mainly relies on the main support legs of the jacket, and there is less need for structural modification of the upper module. The overall workload of offshore construction preparation is relatively small. It has the advantages of high construction efficiency and low construction cost.

[0081] like Figure 20-22 The figure shows a typical state of the semi-submersible multi-purpose transport and disassembly vessel of the present invention operating as a semi-submersible transport vessel, including transporting a floating production storage and offloading vessel 51, a column platform 52, and a semi-submersible production platform 53. Without the obstruction of a forecastle or poop, it can fully utilize its advantages in transporting extra-long and extra-wide offshore equipment. The spacious deck area amidships and aft, as well as the ample cargo space, make the present invention uniquely advantageous for loading large, extra-wide semi-submersible production platforms.

[0082] like Figure 23 As shown, the upper module support frame 55 of the bow extension 1 is used as a structural support for the floating assembly and disassembly of the upper module 54 on the semi-submersible multi-purpose transport and disassembly vessel. The floating installation docking buffer device 56 is used as a buffer docking device for the present invention with the offshore fixed structure during the floating assembly and disassembly operation.

[0083] like Figure 24 As shown, in the stern catamaran float-over operation mode of the semi-submersible multi-purpose transport and assembly vessel of the present invention, the draft of the stern is adjusted by pressure and displacement, transferring the weight of the topside module 54 to be assembled and disassembled between the vessel and an offshore jacket 58. The structural weight of the topside module 54 to be assembled and disassembled is supported by support arms 57 pre-installed on the stern deck and distributed to the main hull structure.

[0084] The above is only a preferred embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. In other words, simple equivalent changes and modifications made according to the scope of the patent application and the content of the invention description are still within the scope of the patent of the present invention.

Claims

1. Semi-submersible multifunctional transport and disassembly vessel, characterized by: The stern is detachably connected to one end of the midship bow, and the other end of the midship bow is detachably connected to a narrow bow extension relative to the midship bow. The stern is a catamaran structure, consisting of two floating island-type submersible hulls, with an empty slot area provided between the two hulls of the stern, and a detachable deck filling structure provided in the empty slot area; at least one movable pontoon is provided at the midship bow; at least two pontoons are provided at the stern, and a control room is provided at the front right side of the midship bow; the bow extension is provided with a bow sealing plate, which is a flat structure; the bottom outer plate of the bow extension is inclined forward, and the forward inclination range of the bottom outer plate is 2-4 meters.

2. The semi-submersible multifunctional transport and disassembly vessel according to claim 1, characterized in that: The control room is arranged on the outer buoyancy support structure of the bow deck amidships.

3. The semi-submersible multifunctional transport and disassembly vessel according to claim 1, characterized in that: The buoyancy boxes are respectively arranged on the side edges of the hull deck on both sides of the empty slot area.

4. The semi-submersible multifunctional transport and disassembly vessel according to claim 3, characterized in that: Two buoyancy boxes are arranged on the side edge of the deck of each hull at the stern of the ship; the buoyancy boxes are fixed on the hull deck by welding or anchoring.

5. The semi-submersible multifunctional transport and disassembly vessel according to claim 4, characterized in that: The buoyancy box consists of a lower buoyancy module and an upper mooring module, and the lower buoyancy module and the upper mooring module are connected by bolts.

6. The semi-submersible multifunctional transport and disassembly vessel according to claim 5, characterized in that: The bottom of the lower buoyancy module is welded or riveted to the main deck, and a power cable junction box is provided therein to communicate with the power cable channel in the pedestrian passage of the main hull.

7. The semi-submersible multifunctional transport and disassembly vessel according to claim 1, characterized in that: A streamlined transition outer plate is provided in the transition area of ​​the bow amidships.

8. The semi-submersible multifunctional transport and disassembly vessel according to claim 7, characterized in that: The transition area is provided with internal transverse strong girders, longitudinal frames, internal longitudinal strong girders, internal longitudinal bulkheads and internal tank decks.

9. The semi-submersible multifunctional transport and disassembly vessel according to claim 1, characterized in that: An arc-shaped transition plate is provided in the inner groove transition area between the bow part and the stern part amidships, and the arc-shaped transition plate is smoothly transitionally connected to the arc-shaped transition outer plate of the stern part amidships.

10. The semi-submersible multifunctional transport and disassembly vessel according to claim 2, characterized in that: A streamlined transition outer plate is provided on the outer floating support structure of the control room.

11. The semi-submersible multifunctional transport and disassembly vessel according to claim 1, characterized in that: The detachable deck filling structure is an assembled filling structure or an integral filling structure; the assembled filling structure is composed of a number of filling-type span beam units, span beam unit panels and span beam unit webs, and the span beam unit panels are welded to form a whole through the filling-type span beam unit internal reinforcement member span beam unit web.

12. The semi-submersible multifunctional transport and disassembly vessel according to claim 11, characterized in that: The bottom of the web of the span beam unit is in an arc shape, and the arc radius is between 20-200 meters.

13. The semi-submersible multifunctional transport and disassembly vessel according to claim 1, 11 or 12, characterized in that: A buffer positioning module is provided on the side wall of the hull in the empty slot area of ​​the catamaran stern, and the buffer positioning module includes a fender, a transverse fender and a longitudinal fender.

14. The semi-submersible multifunctional transport and disassembly vessel according to claim 13, characterized in that: The transverse fender includes a transverse fender base, a transverse fender and a guide fender. The transverse fender base is welded and installed in the inner groove of the hull side wall. The transverse fender is fixed to the transverse surface of the transverse fender base. The guide fenders are respectively fixed on both sides of the transverse fender base. The transverse fender includes a transverse fender panel, a transverse fender elastomer and a transverse fender base. The transverse fender base is fixed to the transverse fender base by welding or riveting, the transverse fender panel is fixed to the transverse fender base, and the transverse fender elastomer is arranged between the transverse fender panel and the transverse fender base.

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