An offshore wind farm wind turbine installation operation engineering vessel and operation method thereof

Abstract

The present invention relates to an offshore wind farm wind turbine installation engineering ship and an operation method thereof, comprising a main hull of a double-side structure, a main deck welded on the top, a crawler crane installed on the main deck, the crawler crane divides the main deck into a component storage area and an impeller assembly area, a main crane is installed in the impeller assembly area, the main crane is located on the right side of the main deck, and an elephant leg tooling is also installed on the side in front of the main crane; a ballast tank balanced with the main crane is arranged in the main hull located at the other side of the main deck; when in use, the crawler crane cooperates with the auxiliary crane to buckle the hub upside down onto the elephant leg tooling, and then the main crane cooperates with the crawler crane to sequentially hoist three blades onto the hub to assemble into an impeller, and finally the main crane cooperates with the crawler crane to hoist the impeller as a whole to the impeller assembly at sea to complete the installation. The engineering ship of the present invention has a reasonable layout, a large carrying capacity, a large operating space, and can meet and be suitable for safe, efficient and free offshore operations.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore engineering vessels, and in particular to an offshore wind farm wind turbine installation engineering vessel and an operation method thereof. Background Art

[0002] The development of renewable energy is popular all over the world, and wind energy is one of the most important new energy sources. As a pollution-free renewable energy development, offshore wind power generation has been highly valued by countries around the world because of its advantages such as better wind energy conditions, no land acquisition issues, no air pollution, and considerable environmental value. It has developed very rapidly, but the transportation and installation of large offshore wind power equipment requires a high level of technical support.

[0003] The most important part of the development and construction of offshore wind farms is offshore installation, which mainly includes the installation of wind turbine foundations, nacelles, and blades. Compared with the installation of onshore wind turbines, offshore construction is much more difficult. With the large-scale wind turbines, small ships in the existing technology cannot meet the requirements of lifting height and lifting capacity. When used, they will have problems with poor maneuverability and positioning performance, and low work efficiency. Slightly strong winds and waves will make it impossible to operate.

[0004] In the existing technology, the installation of offshore wind turbines is carried out by loading wind turbine components or wind turbine foundations on a flat deck ship and towing them to the site, and then the wind turbine installation engineering ship performs the subsequent installation. An offshore wind farm wind turbine installation engineering ship with advanced functions and meeting engineering requirements must not only comprehensively consider factors such as the shipbuilding cost, variable load, deck area, lifting capacity, adaptability to seabed geological conditions, crane layout and selection, weight control, etc., but also needs to consider the on-site construction process and process requirements. Summary of the invention

[0005] In view of the shortcomings in the above-mentioned existing production technology, the applicant provides a rationally structured offshore wind farm wind turbine installation operation engineering vessel and its operation method. The operation engineering vessel has strong comprehensive capabilities and the on-site construction process is safe and efficient, thereby greatly improving the operation efficiency and greatly reducing the operating costs.

[0006] The technical solution adopted by the present invention is as follows:

[0007] An offshore wind farm wind turbine installation engineering vessel comprises a main hull, the main hull is a double-side structure, a main deck is welded on the top of the main hull, a crawler crane is installed on the main deck, the crawler crane divides the main deck into a component storage area and an impeller assembly area, a main crane is installed in the impeller assembly area, the main crane is located on one side of the main deck, and an elephant leg tooling is also installed on the side in front of the main crane; a ballast tank balanced with the main crane is arranged in the main hull located on the other side of the main deck.

[0008] As a further improvement of the above technical solution:

[0009] A plurality of pile fixing chambers are symmetrically welded on both sides of the main hull, and pile legs are installed through each pile fixing chamber. The plurality of pile legs respectively support and lift the main hull through lifting devices in the pile fixing chambers; a single lifting device includes two sets of independent hydraulic latch type lifting systems.

[0010] There are four pile fixing chambers, which are symmetrically installed on both sides of the main hull. The main crane is installed at the pile fixing chamber at the rear of the starboard side of the main hull, and the elephant leg tooling is located between the two pile fixing chambers on the starboard side of the main hull.

[0011] The structure of a single lifting device is as follows: it includes two ring beams which are arranged at intervals up and down and are mounted on the pile legs. The single ring beam is driven by a lifting cylinder to achieve axial movement relative to the pile legs. The ring beam is fixed to the pile legs by a latch which is driven by a hydraulic cylinder. A guide structure is provided between the pile fixing chamber and the pile legs.

[0012] An equipment deck is arranged inside the main hull below the main deck, and an outer tank bottom is arranged at the bottom of the main hull below the equipment deck, and the equipment deck and the outer tank bottom constitute a double bottom structure of the main hull; the equipment deck is divided into multiple cabins by multiple mutually perpendicular longitudinal bulkheads and transverse bulkheads, and the middle part of the equipment deck is arranged in sequence along the bow and stern directions as a living and entertainment area, an auxiliary engine room and a main engine room, and a machine repair room and a switchboard room are arranged on the side of the equipment deck.

[0013] A living waterproof tank, a drinking water tank and a fuel tank are arranged in sequence in the middle of the outer cabin bottom along the bow and stern directions; the ballast tank is arranged at the side of the outer cabin bottom, and the bow and stern of the outer cabin bottom are both provided with ballast tanks; a fresh water tank and a gray water tank are also arranged at the side of the outer cabin bottom, and the remaining cabins are empty cabins.

[0014] A superstructure is arranged in the middle of the bow of the main deck, and the superstructure includes a control room and a living cabin; an in-place mooring system is installed at the bow of the main deck next to the superstructure; towing plate eyes are symmetrically installed at the bow of the main deck; a hydraulically driven four-point mooring system is installed at both sides of the bow and stern of the main deck, and the four-point mooring system includes a positioning anchor.

[0015] The main crane is a full-revolving pile-engraving tower crane with a lifting capacity of 600 tons and a lifting height of 116 meters from the main deck; the crawler crane has a lifting capacity of 200 tons and cooperates with the main crane in construction operations; a 10-ton auxiliary crane is also installed on the main deck in front of the elephant leg tooling.

[0016] The elephant leg tooling is matched with the wheel hub, and the elephant leg tooling fixes the wheel hub through fasteners; a seawater tower and a hose winch system are also installed on the main deck.

[0017] An operation method of an offshore wind farm wind turbine installation operation engineering vessel comprises the following steps:

[0018] Step 1: The engineering ship is towed to the operation area by the anchor boat and initially positioned by the GPS system; the anchor boat transports the positioning anchor of the four-point mooring system to the preset position and drops anchor, adjusts the position of the engineering ship by the positioning anchor, and accurately positions the engineering ship by the length, speed, and dynamic and static tension of the rope;

[0019] Step 2: The lifting cylinders in the pile fixing chamber work, and the two ring beams are alternately driven by the lifting cylinders to move axially relative to the pile legs, and the hydraulic cylinders drive the pins to fix the ring beams relative to the pile legs, so that the engineering ship is detached and lifted out of the sea level, and the seawater tower and hose winch system are inserted into the sea level;

[0020] Step 3: The crawler crane and the auxiliary crane cooperate to lift the wheel hub from the component storage area and buckle it onto the elephant leg tooling, and fasten the wheel hub to the elephant leg tooling with fasteners;

[0021] Step 4: The crawler crane cooperates with the main crane to lift the three fan blades from the component storage area to the hub on the elephant leg tooling in sequence, and assemble the fan blades and the hub to form an impeller through fasteners;

[0022] Step 5: Change the pitch of the impeller blades in the fourth step to the preset position; the main crane cooperates with the crawler crane to lift the impeller to the impeller assembly, so that the flange plane of the impeller hub and the flange plane of the impeller assembly generator are at the same horizontal plane;

[0023] Step 6: The crawler crane unscrews the rigging, docks the impeller and the impeller assembly, and completes the installation.

[0024] The beneficial effects of the present invention are as follows:

[0025] The invention has a compact and reasonable structure, is easy to operate, and is optimized in terms of overall functional layout. The design takes into account normal operation under level 4 sea conditions and safe migration under level 5 sea conditions, meeting the conditions for sailing operations for more than 260 days a year, thereby ensuring that the ship meets the characteristics of large load-bearing capacity, safety, high efficiency, and freedom of operation in the development, construction, and installation of offshore wind farms;

[0026] The present invention provides a self-elevating wind power installation platform which can be accurately positioned, efficiently lifted and lowered, is suitable for severe sea conditions, is safe, flexible, and has efficient operation. It maximizes the use of the main deck area, improves the utilization rate of the operating area around the main deck, and can realize the rapid and large-scale lifting and transfer of major components such as wind turbine blades, hubs, towers, and nacelles, the efficient assembly of impellers on the main deck, and the integrated lifting and installation of impellers, which greatly reduces the high-altitude operation time of operators, reduces the difficulty of manual operations and the risk factor of operations, and greatly guarantees and meets the safe, efficient, and convenient installation of wind turbine components in offshore wind farms.

[0027] The present invention also includes the following advantages:

[0028] The hydraulic latch-type lifting system has a small volume, low investment cost, light weight and easy maintenance; the pile legs adopt a cylindrical structure, light weight and small volume; the lifting device adopts a double-acting ring beam double hydraulic system, and the two lifting systems work independently and have lifting capabilities;

[0029] The main crane is installed on the starboard pile chamber of the main hull. It is an asymmetric main crane layout, which not only frees up a large amount of main deck working space, but also allows more flexibility and freedom when lifting workpieces for positioning and adjusting directions. Combined with a crawler crane, it can move large wind turbine components over a large range to designated installation locations or workpiece assembly locations. Ballast tanks are arranged inside the main hull to make the main hull overall stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the present invention.

[0031] Figure 2 for Figure 1 Top view of the .

[0032] Figure 3 It is a structural schematic diagram of the pile fixing chamber of the present invention.

[0033] Figure 4 for Figure 3 Partial cross-sectional view along AA.

[0034] Figure 5 It is a structural schematic diagram of the equipment deck of the present invention.

[0035] Figure 6 It is a structural schematic diagram of the outer tank bottom of the present invention.

[0036] Figure 7 It is a schematic diagram of the present invention when the impeller is installed.

[0037] Figure 8 This is a schematic diagram of the present invention when the impeller is installed to the impeller assembly.

[0038] Among them: 1. Main hull; 2. Pile legs; 3. Pile fixing room; 4. Main crane; 5. Hose winch system; 6. Seawater tower; 7. Auxiliary crane; 8. Superstructure; 9. In-position anchoring system; 10. Four-point anchoring system; 11. Towing plate eye; 12. Elephant leg tooling; 13. Crawler crane; 14. Crawler driving area; 15. Parts storage area; 16. Hydraulic pump station; 17. Auxiliary engine room; 18. Main engine room; 19. Machine repair room; 20. Switchboard room; 21. Ballast tank; 22. Fuel tank; 23. Fresh water cabin; 24. gray water tank; 25. drinking water tank; 26. living watertight cabin; 27. impeller; 28. impeller assembly; 29. ​​sea level; 30. living and entertainment area; 101. main deck; 102. equipment deck; 103. outer bottom; 104. transverse bulkhead; 105. longitudinal bulkhead; 31. ring beam; 32. lifting cylinder; 33. guide structure; 34. latch; 35. hydraulic cylinder; 81. control room; 82. living cabin; 271. blade one; 272. blade two; 273. blade three. DETAILED DESCRIPTION

[0039] The specific implementation of the present invention is described below in conjunction with the accompanying drawings.

[0040] like Figure 1 and Figure 2 As shown, the offshore wind farm wind turbine installation operation engineering vessel of this embodiment includes a main hull 1, the main hull 1 is a double-side structure, a main deck 101 is welded on the top of the main hull 1, a crawler crane 13 is installed on the main deck 101, the crawler crane 13 divides the main deck 101 into a component storage area 15 and an impeller assembly area, the impeller assembly area is installed with a main crane 4, the main crane 4 is located on the right side of the main deck 101, and an elephant leg tooling 12 is also installed on the side in front of the main crane 4; a ballast tank 21 balanced with the main crane 4 is arranged in the main hull 1 located on the other side of the main deck 101.

[0041] A plurality of pile-fixing chambers 3 are symmetrically welded on both sides of the main hull 1, and a pile leg 2 is installed through each pile-fixing chamber 3. The plurality of pile legs 2 respectively support and lift the main hull 1 through the lifting device in the pile-fixing chamber 3; the single lifting device adopts an inverted cylinder type, including two sets of independent hydraulic latch type lifting systems.

[0042] There are four pile fixing chambers 3 symmetrically installed on both sides of the main hull 1 . The main crane 4 is installed at the pile fixing chamber 3 at the rear of the starboard side of the main hull 1 , and the elephant leg tooling 12 is located between the two pile fixing chambers 3 on the starboard side of the main hull 1 .

[0043] like Figure 3As shown in FIG. 1 , the structure of a single lifting device is as follows: it includes two ring beams 31 arranged at intervals in the upper and lower parts and sleeved on the pile leg 2. The single ring beam 31 is driven by a lifting cylinder 32 to realize axial movement relative to the pile leg 2. The ring beam 31 is fixed to the pile leg 2 by a latch 34, and the latch 34 is driven by a hydraulic cylinder 35. Figure 4 As shown; a guide structure 33 is provided between the pile chamber 3 and the pile leg 2, the guide structure 33 is made of wear-resistant material, having the function of guiding the pile leg 2 and bearing the horizontal load; the hydraulic pump station 16 of the lifting device is provided on the equipment deck 102 within the main hull 1.

[0044] A single ring beam 31 is provided with a pin hole along the circumferential direction, and a plurality of circular holes cooperating with the pin hole are provided on the pile leg 2 along the axial direction. The latch pin 34 passes through one of the pin holes and the circular hole under the drive of the hydraulic cylinder 35 to realize the connection between the ring beam 31 and the pile leg 2 .

[0045] An equipment deck 102 is provided in the main hull 1 below the main deck 101, and an outer bilge 103 is provided at the bottom of the main hull 1 below the equipment deck 102. The equipment deck 102 and the outer bilge 103 constitute a double bottom structure of the main hull 1 to enhance the anti-collision performance; Figure 5 As shown, the equipment deck 102 is divided into multiple cabins by multiple mutually perpendicular longitudinal bulkheads 105 and transverse bulkheads 104. The middle part of the equipment deck 102 is arranged along the bow and stern directions with a living and entertainment area 30, an auxiliary engine room 17 and a main engine room 18 in sequence. A maintenance room 19 and a switchboard room 20 are arranged on the side of the equipment deck 102.

[0046] like Figure 6 As shown, a living waterproof tank 26, a drinking water tank 25 and a fuel tank 22 are sequentially arranged in the middle part of the outer tank bottom 103 along the bow and stern directions; a ballast tank 21 is arranged on the left side of the outer tank bottom 103, and the bow and stern of the outer tank bottom 103 are both provided with ballast tanks 21; a fresh water tank 23 and a gray water tank 24 are also arranged on the side of the outer tank bottom 103, and the remaining cabins are empty.

[0047] The longitudinal bulkhead 105 and the transverse bulkhead 104 form a box structure inside the main hull 1, forming a main structure with sufficient torsional rigidity.

[0048] A superstructure 8 is arranged in the middle position of the bow of the main deck 101, and the superstructure 8 includes a control room 81 and a living cabin 82; an in-place mooring system 9 is installed at the bow of the main deck 101 next to the superstructure 8; towing plate eyes 11 are symmetrically installed at the bow of the main deck 101; a hydraulically driven four-point mooring system 10 is installed on both sides of the bow and stern of the main deck 101, and the four-point mooring system 10 includes a positioning anchor.

[0049] The main crane 4 is a full-revolving pile-wrapped tower crane with a lifting capacity of 600 tons and a lifting height of 116 meters from the main deck 101; the crawler crane 13 has a lifting capacity of 200 tons, and the crawler crane 13 cooperates with the main crane 4 for construction operations, and the crawler driving area 14 of the crawler crane 13 is arranged in a T-shaped structure along the bow and stern directions of the main hull 1; a 10-ton auxiliary crane 7 is also installed on the main deck 101 in front of the elephant leg tooling 12.

[0050] The elephant leg tooling 12 cooperates with the wheel hub, and the elephant leg tooling 12 fixes the wheel hub through fasteners; a seawater tower 6 and a hose winch system 5 are also installed on the main deck 101; when the main hull 1 of the engineering ship is lifted out of the water by a lifting device for operation, the seawater tower 6 and the hose winch system 5 supply seawater during the operation of the engineering ship and serve as backup for each other.

[0051] The three blades are mounted on a hub to complete the assembly of an impeller 27, and then the impeller 27 is installed as a whole on the top of the impeller assembly 28 at sea to complete the assembly of the fan.

[0052] The operation engineering vessel is a non-powered platform with a total length of about 120 to 130 meters, a width of about 35 to 40 meters, and a depth of about 3 to 7 meters.

[0053] The operation method of the offshore wind farm wind turbine installation operation engineering vessel of this embodiment includes the following steps:

[0054] Step 1: The engineering ship is towed to the operation area by the anchor boat and initially positioned by the GPS system; the anchor boat transports the positioning anchor of the four-point mooring system 10 to the preset position and drops anchor, adjusts the position of the engineering ship by the positioning anchor, and accurately positions the engineering ship by the length, speed, and dynamic and static tension of the outgoing rope;

[0055] Step 2: The lifting cylinder 32 in the pile fixing chamber 3 works, and the two ring beams 31 are alternately driven by the lifting cylinder 32 to move axially relative to the pile legs 2, and the pins 34 are driven by the hydraulic cylinder 35 to fix the ring beams 31 relative to the pile legs 2, so that the engineering ship is separated and lifted out of the sea level 29, and the seawater tower 6 and the hose winch system 5 are inserted into the sea level 29;

[0056] Step 3: The crawler crane 13 and the auxiliary crane 7 cooperate to lift the wheel hub from the component storage area 15 and buckle it onto the elephant leg tooling 12, and fasten the wheel hub to the elephant leg tooling 12 by fasteners;

[0057] In actual use, blades, hubs and other parts can also be taken from other tugboats.

[0058] Step 4: The crawler crane 13 cooperates with the main crane 4 to sequentially hoist the three fan blades, blade 1 271, blade 2 272, and blade 3 273, from the component storage area 15 to the hub on the elephant leg tooling 12, and assemble the fan blades and the hub to form an impeller 27 through fasteners. Figure 7 As shown;

[0059] Step 5: Shift the blades of the impeller 27 in the fourth step to the preset position; the main crane 4 cooperates with the crawler crane 13 to lift the impeller 27 to the impeller assembly 28, so that the flange plane of the impeller 27 hub and the flange plane of the impeller assembly 28 generator are at the same horizontal plane, such as Figure 8 As shown;

[0060] Step 6: The crawler crane 13 is rigged, and the impeller 27 is docked with the impeller assembly 28 to complete the installation.

[0061] The present invention is a self-elevating wind power installation platform which is suitable for severe sea conditions and is safe, flexible and efficient in operation. It realizes efficient assembly of the impeller on the main deck and installation of the impeller and offshore impeller components, and has high operating efficiency and good performance.

[0062] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. An offshore wind farm wind turbine installation engineering vessel, comprising a main hull (1), characterized in that: The main hull (1) is a double-side structure, a main deck (101) is welded on the top of the main hull (1), a crawler crane (13) is installed on the main deck (101), the crawler crane (13) divides the main deck (101) into a component storage area (15) and an impeller assembly area, a main crane (4) is installed in the impeller assembly area, the main crane (4) is located on one side of the main deck (101), and an elephant leg tooling (12) is also installed on the side in front of the main crane (4); a ballast tank (21) balanced with the main crane (4) is arranged in the main hull (1) located on the other side of the main deck (101); The elephant leg tooling (12) cooperates with the wheel hub, and the elephant leg tooling (12) fixes the wheel hub via fasteners; a seawater tower (6) and a hose winch system (5) are also installed on the main deck (101); A superstructure (8) is arranged in the middle of the bow of the main deck (101), and the superstructure (8) includes a control room (81) and a living cabin (82); an in-position anchoring system (9) is installed at the bow of the main deck (101) next to the superstructure (8); towing plate eyes (11) are symmetrically installed at the bow of the main deck (101); a hydraulically driven four-point anchoring system (10) is installed at both the bow and stern of the main deck (101), and the four-point anchoring system (10) includes a positioning anchor; The main crane (4) is a full-slewing pile-wrapping tower crane with a lifting capacity of 600 tons and a lifting height of 116 meters from the main deck (101); the crawler crane (13) has a lifting capacity of 200 tons and cooperates with the main crane (4) in construction operations; a 10-ton auxiliary crane (7) is also installed on the main deck (101) in front of the elephant leg tooling (12); The operation includes the following steps: Step 1: The engineering vessel is towed to the operation area by the anchor boat and initially positioned by the GPS system; the anchor boat transports the positioning anchor of the four-point mooring system (10) to the preset position and drops anchor, adjusts the position of the engineering vessel by the positioning anchor, and accurately positions the engineering vessel by the length, speed, and dynamic and static tension of the rope; Step 2: The lifting cylinder (32) in the pile fixing chamber (3) works, and the two ring beams (31) are alternately driven by the lifting cylinder (32) to move axially relative to the pile legs (2), and the hydraulic cylinder (35) drives the latch (34) to fix the ring beam (31) relative to the pile legs (2), so that the engineering ship is detached and lifted out of the sea level (29), and the seawater tower (6) and the hose winch system (5) are inserted into the sea level (29); Step 3: The crawler crane (13) and the auxiliary crane (7) cooperate to lift the wheel hub from the component storage area (15) and buckle it onto the elephant leg tooling (12), and fasten the wheel hub to the elephant leg tooling (12) by fasteners; Step 4: The crawler crane (13) cooperates with the main crane (4) to sequentially hoist the three fan blades from the component storage area (15) to the hub on the elephant leg tooling (12), and assemble the fan blades and the hub to form an impeller (27) by fasteners; Step 5: pitch the blades of the impeller (27) in the fourth step to a preset position; the main crane (4) cooperates with the crawler crane (13) to lift the impeller (27) to the impeller assembly (28) so that the flange plane of the impeller (27) hub and the flange plane of the impeller assembly (28) generator are on the same horizontal plane; Step 6: The crawler crane (13) is slinged and the impeller (27) is docked with the impeller assembly (28) to complete the installation.

2. An offshore wind farm wind turbine installation engineering vessel as claimed in claim 1, characterized in that: A plurality of pile-fixing chambers (3) are symmetrically welded on both sides of the main hull (1); a pile leg (2) is installed through each pile-fixing chamber (3); and the plurality of pile legs (2) respectively support and lift the main hull (1) through lifting devices in the pile-fixing chamber (3); and a single lifting device comprises two sets of mutually independent hydraulic latch-type lifting systems.

3. An offshore wind farm wind turbine installation engineering ship as claimed in claim 2, characterized in that: The number of the pile fixing chambers (3) is four and they are symmetrically installed on both sides of the main hull (1). The main crane (4) is installed at the pile fixing chamber (3) at the rear of the starboard side of the main hull (1), and the elephant leg tooling (12) is located between the two pile fixing chambers (3) on the starboard side of the main hull (1).

4. An offshore wind farm wind turbine installation engineering ship as claimed in claim 2, characterized in that: The structure of a single lifting device is as follows: it comprises two ring beams (31) which are arranged at an interval up and down and are sleeved on the pile legs (2); the single ring beam (31) is driven by a lifting cylinder (32) to achieve axial movement relative to the pile legs (2); the ring beam (31) is fixed to the pile legs (2) by a latch (34), and the latch (34) is driven by a hydraulic cylinder (35); and a guide structure (33) is provided between the pile fixing chamber (3) and the pile legs (2).

5. The offshore wind farm wind turbine installation engineering ship according to claim 1, characterized in that: An equipment deck (102) is arranged in the main hull (1) below the main deck (101), and an outer bilge (103) is arranged at the bottom of the main hull (1) below the equipment deck (102); the equipment deck (102) and the outer bilge (103) constitute a double bottom structure of the main hull (1); the equipment deck (102) is divided into a plurality of cabins by a plurality of mutually perpendicular longitudinal bulkheads (105) and transverse bulkheads (104); the middle portion of the equipment deck (102) is arranged in sequence along the bow and stern directions as a living and entertainment area (30), an auxiliary engine room (17) and a main engine room (18); and a machine repair room (19) and a switchboard room (20) are arranged on the side of the equipment deck (102).

6. An offshore wind farm wind turbine installation engineering ship as claimed in claim 5, characterized in that: A living waterproof tank (26), a drinking water tank (25) and a fuel tank (22) are sequentially arranged in the middle of the outer bilge bottom (103) along the bow and stern directions; a ballast tank (21) is arranged at the side of the outer bilge bottom (103), and the bow and stern of the outer bilge bottom (103) are both provided with a ballast tank (21); a fresh water tank (23) and a grey water tank (24) are also arranged at the side of the outer bilge bottom (103), and the remaining cabins are empty cabins.

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