Stretching net fishing boat hull structure with composite hull structure

Abstract

According to the net fishing boat body structure with the composite boat body structure, the middle inner keel is arranged in the middle of the boat body, and the rib plates are connected with the main force bearing frameworks in the supporting parts on the two sides of the boat body, so that the longitudinal bending strength of the boat body can be effectively improved when the fishing boat executes anchoring and weighing operations; therefore, longitudinal structure deformation and transverse position deformation of the ship body are obviously inhibited; the net stretching suspender can rotate flexibly, so that the net stretching operation efficiency is improved; the fishing boat body structure not only has good buoyancy and stability, ensures operation safety under complex sea conditions, but also has excellent durability and strength, meets the requirement for long-term high-strength operation, and provides an economical, efficient and safe new solution for fishery production.

Description

Technical Field

[0001] This utility model relates to the field of fishing gear technology, and in particular to a hull structure for a net fishing vessel with a composite hull structure. Background Technology

[0002] Set net fishing vessels use an anchored hull as a fixed platform and deploy fishing gear via side-mounted jibs. To improve fishing efficiency, some vessel types adopt a "double net on one vessel" mode, meaning a single vessel deploys two fishing nets simultaneously. This type of operation places higher demands on the structural strength and capsizing stability of the hull. Traditional set net fishing vessels use a single continuous keel connected to equally spaced ribs, resulting in insufficient lateral support stiffness. This leads to the inability to effectively distribute concentrated loads during side-mounted jib operation, causing stress concentration at the keel-rib connection point, which easily leads to structural cracking. Furthermore, the jib base is fixed to the side bulwark and not rigidly connected to the main ribs or ribs, meaning the operating load is only partially borne by the bulwark, lacking a skeletal load-sharing mechanism, exacerbating hull fatigue damage. In addition, the hull frame lacks multi-directional cross-bracing components, resulting in insufficient torsional stiffness. Under wind, waves, or uneven loading conditions, it is prone to twisting and deformation, seriously affecting the stability of net deployment and operational safety. The aforementioned structural defects cause problems such as deformation, cracking, and shortened lifespan of the hull during frequent operations, which restricts the efficiency of high-intensity fishing. Summary of the Invention

[0003] This utility model discloses a hull structure for a net-caught fishing vessel with a composite hull structure, in order to overcome the above-mentioned technical problems.

[0004] To achieve the above objectives, the technical solution of this utility model is as follows:

[0005] A composite hull structure for a net-casting fishing vessel includes: a hull, a main mast, two net-casting booms, a fishing net, multiple ribs, and an inner keel;

[0006] The hull is equipped with two sets of support sections and a storage section; the storage section is located between the two sets of support sections and contains several fish cabins connected in sequence; the support section is equipped with a main load-bearing frame.

[0007] The inner keel is fixedly installed at the bottom of the hull, and the inner keel is parallel to the direction of travel of the hull.

[0008] The rib is fixedly installed at the bottom of the hull, perpendicular to the inner keel, and both ends of the rib are fixedly connected to the main load-bearing frame inside the two sets of the support parts, respectively.

[0009] The main mast is fixed vertically to the bottom of the hull;

[0010] A net-lifting machine is fixedly installed on the top of the deck of the hull;

[0011] The two aforementioned net-stretching booms are respectively installed on both sides of the hull;

[0012] One end of the net-casting boom is connected to the rotating part of the net-casting boom, the rotating part of the net-casting boom is fixedly connected to the hull's bulwark panel, and the other end of the net-casting boom is connected to the net-casting boom rope; the fishing net is connected to the net-casting boom.

[0013] The net-laying boom rope is connected to the net-lifting machine via the top of the main mast;

[0014] When fishing begins, the net boom can rotate horizontally and vertically around the end connected to the rotating part of the net boom.

[0015] Furthermore, the rotating part of the tensioning rod includes a bushing and a rod shaft;

[0016] The bushing is fixedly connected to the hull's bulkhead panel; the boom shaft is coaxially disposed inside the bushing.

[0017] A limiting pin is provided on the outer wall surface at the bottom of the boom shaft; the limiting pin is located below the bushing.

[0018] The top of the boom shaft extends through the hull's bulkhead panel, and a first connecting piece is fixedly installed on the top of the boom shaft; the first connecting piece is parallel to the axis of the boom shaft.

[0019] The end of the tension net rod that connects to the rotating part of the tension net rod is provided with a second connecting piece; the second connecting piece is parallel to the axis of the tension net rod.

[0020] The first connecting piece and the second connecting piece are rotatably connected, and the rotation axis is perpendicular to the first connecting piece.

[0021] Furthermore, the main load-bearing frame includes deck beams, second ribs, ribs, vertical supports, deck longitudinal girder, and side inner keel;

[0022] The side inner keel is fixedly installed at the bottom of the hull and is parallel to the middle inner keel;

[0023] The deck beams and deck girders are both fixedly installed at the bottom of the deck of the hull, and the deck girders are parallel to the inner keel; the deck beams and deck girders are perpendicular.

[0024] The two ends of the vertical support are respectively fixed perpendicularly to the deck girder and the side inner keel;

[0025] The second rib is fixedly installed at the bottom of the hull, and one end of the second rib is fixed perpendicularly to the side inner keel;

[0026] The rib is located on the side of the inner keel away from the middle inner keel, and both ends of the rib are fixedly connected to the deck beam and the second rib, respectively.

[0027] Furthermore, the bottom plate, side plates, deck, and bulwark panels of the hull are all made of HDPE material.

[0028] Furthermore, a fixed pulley is provided on the main mast;

[0029] The net-laying sling rope is connected to the net-lifting machine and the net-laying sling via a fixed pulley at the top of the main mast.

[0030] Beneficial Effects: This utility model discloses a hull structure for a net-casting vessel with a composite hull structure. By setting an inner keel in the middle of the hull and connecting the main load-bearing frame inside the support parts on both sides of the hull through rib plates, it can effectively improve the longitudinal bending strength of the hull when the fishing vessel is anchoring and raising anchor, thereby significantly suppressing longitudinal structural deformation and lateral deformation of the hull. The net-casting boom can rotate flexibly, improving the efficiency of net-casting operations. The hull structure of this utility model not only has good buoyancy and stability, ensuring operational safety in complex sea conditions, but also has excellent durability and strength, meeting the needs of long-term high-intensity operations, and providing an economical, efficient and safe new solution for fishery production. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall hull structure of the net-trapping fishing boat of this utility model;

[0033] Figure 2 This is a front view schematic diagram of the hull structure of the net-casting fishing boat in this embodiment of the present utility model;

[0034] Figure 3 This is a schematic diagram of the rotating part of the tensioning rod in an embodiment of the present utility model;

[0035] Figure 4 This is a front view schematic diagram of the main load-bearing frame in an embodiment of this utility model;

[0036] Figure 5 This is a schematic diagram showing the connection between the main load-bearing frame and the bottom of the ship in an embodiment of this utility model;

[0037] Figure 6 This is a schematic diagram of the mast base in an embodiment of the present utility model;

[0038] Figure 7 This is a schematic diagram of the overall structure of the main load-bearing skeleton in an embodiment of this utility model.

[0039] The components include: 1. Hull; 11. Bottom plate; 12. Side plate; 13. Deck; 14. Bulwark panel; 2. Support section; 21. Deck beam; 22. Second rib; 23. Rib; 24. Vertical support; 25. Deck longitudinal girder; 26. Side inner keel; 3. Storage section; 31. Fish hold; 4. Main mast; 41. Fixed pulley; 42. Base pad; 43. Mast base; 44. Diagonal tie rod; 5. Net-setting boom; 51. Net-setting boom rope; 52. Bushing; 53. Boom shaft; 54. Limit pin; 55. First connecting piece; 56. Second connecting piece; 57. Connector; 7. Rib; 8. Inner inner keel; 9. Net-lifting machine; 100. Anchor; 101. Anchor chain; 102. Winch; 103. Guide chain roller. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0041] This embodiment describes a hull structure for a net-caught fishing vessel with a composite hull structure, such as... Figure 1-7 As shown, it includes: hull 1, main mast 4, two net-casting booms 5, fishing net (not shown in the figure), multiple ribs 7, and inner keel 8;

[0042] The hull 1 is provided with two sets of support sections 2 and storage sections 3 inside; the storage section 3 is located between the two sets of support sections 2, and the storage section 3 is provided with a plurality of fish cabins 31 connected in sequence; the support section 2 is provided with a main load-bearing frame inside;

[0043] The inner keel 8 is fixedly installed at the bottom of the hull 1 and is fixedly connected to the bottom plate 11. The inner keel 8 is parallel to the direction of travel of the hull 1.

[0044] The rib plate 7 is fixedly installed at the bottom inside the hull 1 and is fixedly connected to the bottom plate 11. The rib plate 7 is perpendicular to the inner keel 8, and both ends of the rib plate 7 are fixedly connected to the main load-bearing frame inside the two sets of support parts 2 respectively.

[0045] The main mast 4 is fixed vertically to the bottom of the hull 1;

[0046] A net-lifting machine 9 is fixedly installed on the top of the deck 13 of the hull 1;

[0047] The two net-stretching booms 5 are respectively installed on both sides of the hull 1;

[0048] One end of the net-laying boom 5 is connected to the rotating part of the net-laying boom, and the rotating part of the net-laying boom is fixedly connected to the bulwark panel 14 of the hull 1. The other end of the net-laying boom 5 is connected to the net-laying boom rope 51; the connection is with the net-laying boom.

[0049] The net-laying hoisting rope 51 is connected to the net-lifting machine 9 via the top of the main mast 4;

[0050] When fishing begins, the net-holding boom 5 can rotate horizontally and vertically around the end connected to the rotating part of the net-holding boom.

[0051] Preferably, the rotating part of the tensioning rod includes a bushing (steel pipe) 52 and a rod shaft 53;

[0052] The bushing 52 is fixedly connected to the bulwark panel 14 of the hull 1; the boom shaft 53 is coaxially disposed inside the bushing 52.

[0053] A limiting pin 54 is provided on the outer wall surface at the bottom of the boom shaft 53; the limiting pin 54 is located below the bushing 52;

[0054] The top of the boom shaft 53 extends through the bulwark panel 14 of the hull 1, and a first connecting piece 55 is fixedly provided on the top of the boom shaft 53; the first connecting piece 55 is parallel to the axis of the boom shaft 53.

[0055] The end of the tension net rod 5 that connects to the rotating part of the tension net rod is provided with a second connecting piece 56; the second connecting piece 56 is parallel to the axis of the tension net rod 5;

[0056] The first connecting piece 55 is rotatably connected to the second connecting piece 56, and the rotation axis is perpendicular to the first connecting piece 55.

[0057] Specifically, in this embodiment, the boom shaft 53 can rotate inside the bushing 52. To prevent the boom shaft from moving up and down inside the bushing, a limit pin 54 is provided on the outer wall surface at the bottom of the boom shaft. Both the first connecting piece 55 and the second connecting piece 56 have holes, allowing for the rotational connection of the first connecting piece 55 and the second connecting piece 56 by inserting bolts into the holes. When fishing begins, the net-casting boom 5 can rotate in a direction parallel to the horizontal plane, centered on the end connected to the bulwark panel 14 of the hull 1, through the rotation of the boom shaft 53 within the bushing 52. Simultaneously, the rotation of the first connecting piece 55 and the second connecting piece 56 allows the net-casting boom to move in a direction perpendicular to the horizontal plane, enabling the other end of the boom to enter the water for fishing.

[0058] Preferably, the main load-bearing frame includes a deck beam 21, a second rib 22, a rib 23, a vertical support 24, a deck girder 25, and an inner side keel 26.

[0059] The side inner keel 26 is fixedly installed at the bottom inside the hull 1 and is parallel to the middle inner keel 8;

[0060] The deck beam 21 and the deck girder 25 are both fixedly installed at the bottom of the deck 13 of the hull 1, located at the top inside the hull 1, and the deck girder 25 is parallel to the inner keel 8; the deck beam 21 and the deck girder 25 are perpendicular.

[0061] The two ends of the vertical support 24 are respectively fixed perpendicularly to the deck girder 25 and the side inner keel 26;

[0062] The second rib plate 22 is fixedly installed at the bottom inside the hull 1 and is fixedly connected to the bottom plate 11. One end of the second rib plate 22 is fixed perpendicularly to the side inner keel 26.

[0063] The rib 23 is located on the side of the inner keel 26 away from the middle inner keel 8, and the two ends of the rib 23 are fixedly connected to the deck beam 21 and the second rib plate 22, respectively.

[0064] Specifically, in this embodiment, the main load-bearing frame is based on a steel frame with H-beam main keel to ensure the structural strength and operational stability of the hull. The transverse members (including deck beams 21, second ribs 22, and ribs 23) and longitudinal members (deck girder 25 and side inner keel 26) are all made of channel steel, which are cross-welded to form a spatial grid frame. Each steel component panel is fitted with a high-density polyethylene (HDPE) connecting substrate, which is fixed to the steel frame with high-strength bolts and seamlessly fused with the HDPE hull outer plate through a hot-melt welding process, forming a continuous steel-plastic composite interface. This allows for a distributed load transfer path between all steel frame components and the outer plate, significantly improving the overall bending stiffness and torsional stability of the structure while ensuring the hull's lightweight design, and avoiding fatigue failure caused by localized stress concentration.

[0065] Specifically, in this embodiment, the hull plating and deck are made of HDPE material, fully utilizing its excellent corrosion resistance and lightweight properties. This composite structure maintains the overall structural strength of the hull while significantly reducing maintenance requirements in the marine environment, eliminating the need for additional anti-corrosion treatment. Furthermore, the smooth surface properties of HDPE material help improve navigation efficiency and reduce fuel consumption, thereby enhancing the ship's economics.

[0066] Preferably, the bottom plate 11, side plate 12, deck 13 and bulwark panel 14 of the hull 1 are all made of HDPE material.

[0067] Specifically, in this embodiment, the hull 1 includes a bottom plate 11, a side plate 12, a deck 13, and a bulwark panel 14; the bottom plate 11, the side plate 12, and the deck 13 together form a space that can accommodate the support part 2 and the storage part 3.

[0068] Preferably, a fixed pulley 41 is provided on the main mast 4;

[0069] The net-laying sling rope 51 is connected to the net-lifting machine 9 and the net-laying sling 5 via the fixed pulley 41 at the top of the main mast 4;

[0070] Specifically, in this embodiment, the anchor 100 is directly connected to the winch 102 via the anchor chain 101, and the winch 102 is fixed to the hull. The anchor chain 101 is normally controlled by the winch for raising and lowering, and the anchor chain is always kept taut regardless of whether it is in operation.

[0071] Specifically, when the fishing boat is not operating, the anchor 100 is suspended below the bow, and the metal rod (anchor rod) of the anchor 100 is locked in the groove of the guide chain roller 103 to prevent the anchor 100 from swinging left and right or slipping off.

[0072] Specifically, in this embodiment, the main mast 4 is fixedly connected to the inner keel 8 (H-beam) and is located at the intersection of the inner keel and the rib plate. A base plate 42 is provided at the bottom. As shown in the figure, it includes a mast base 43, diagonal braces 44, etc. A flange is welded to the bottom of the main mast 4 (for connection with the mast base). The diagonal braces 44 are symmetrically distributed around the base and are welded and fixed to the hull structure (rib plate, inner keel) to enhance the stability of the mast.

[0073] Specifically, the lower end of the main mast is inserted into the pre-drilled hole in the mast base. The mast flange is aligned with the base flange, and bolts are inserted into the flange holes and tightened to achieve vertical fixation of the mast. After the lower end of the mast is inserted into the base, a pin is inserted to lock it in place, preventing the mast from detaching from the base. The inner keel (H-beam) and ribs (channel steel) can distribute the mast load to the hull structure.

[0074] Specifically, the inner keel in this implementation uses H-beams with the same height as the ribs to ensure uniform stress distribution. In each cross-section, channel steel is used for the added steel components. To enhance the connection between the steel components and the HDPE sheets, a transition connection structure is installed between them. The steel components and HDPE components are bolted together, while the HDPE components are fixed together by welding, thus achieving effective integration of the entire structure. The steel components inside the hull are continuously arranged in both the transverse and longitudinal directions, forming a complete steel frame. This steel frame structure not only provides strong support for the hull but also effectively compensates for the low elastic modulus and high deflection of HDPE material, improving the overall stiffness and stability of the hull and ensuring that the hull maintains high structural strength under stress.

[0075] Specifically, in this embodiment and the second category, HDPE material is used to connect the I-beams of the inner keel. The web of the I-beam is connected to the strip plate by bolts, the face plate of the HDPE rib is connected to the face plate of the channel steel by bolts, and the channel steel is fixed to the I-beam by welding. This design achieves an effective connection between the HDPE rib, the channel steel, and the I-beam, ensuring the integrity of the structure and the continuity of load transfer.

[0076] The gillnet fishing vessel of this embodiment can be used for fishing operations in inland waterways. It operates using gillnets and, depending on the selected configuration, can be used to catch fish, shrimp, and other aquatic products in the middle and upper layers of water. The hull is constructed by welding high-density polyethylene sheets and has an internal steel frame structure. It is unpainted externally and is driven by a diesel outboard motor, with single-engine, single-propeller propulsion.

[0077] Specifically, in this embodiment, the ship's navigation is achieved by the diesel engine driving the stern outboard motor via a belt. At this time, the two net-laying booms are placed inside the bow mooring bollard along the length of the ship. The cables (net-laying boom ropes) connected to the net-laying booms are taut to prevent the booms from moving. The anchor is suspended at the bow, and the anchor rod sits on the guide chain roller. The anchor chain connected to the anchor is taut to prevent the anchor from falling.

[0078] When the vessel arrives at the work area, the main engine is put into neutral to provide power to the winch and net hauling machine. The winch is operated to drop the anchor into the water and secure the vessel. After securing the vessel, the ropes connecting the net-laying booms on both sides are wound onto the shafts on both sides of the net hauling machine, so that the net-laying booms are horizontal on both sides of the hull and maintained in the current state for fishing operations.

[0079] This embodiment has the following beneficial effects:

[0080] This embodiment effectively improves the longitudinal bending strength of the hull when the fishing vessel is anchoring and raising anchor by strengthening components such as the inner keel, side inner keel, and deck longitudinal girder. This significantly suppresses the longitudinal structural deformation of the hull.

[0081] This embodiment provides lateral structural strength for fishing vessels during net-casting operations through components such as ribs, second ribs, and deck beams, thereby preventing hull deformation in the lateral position.

[0082] This embodiment uses an integral frame-type reinforced structure composed of steel inner keel, side inner keel, ribs, rib plates, deck beams and deck longitudinal girder to lower the ship's center of gravity height, thereby improving the ship's stability performance.

[0083] This embodiment uses components such as the tensioning rod base and the rod pivot to enable the rod to rotate flexibly, thereby improving the efficiency of tensioning operations.

[0084] This embodiment uses components such as flanges and bolts to achieve a detachable connection between the main mast and the main keel panel, which not only facilitates maintenance but also efficiently transfers the mast's operating load to the main load-bearing structure.

[0085] In summary, the steel frame structure of this embodiment provides robust support for the hull, effectively addressing the issues of low elastic modulus and excessive deflection of HDPE material. This allows the hull to maintain high stability under stress, reducing or preventing deformation. Furthermore, compared to all-steel fishing vessels, the composite structure of this embodiment maintains high strength while reducing the thickness of the HDPE sheet used, thereby lowering material costs. Additionally, the elimination of complex anti-corrosion treatment further reduces maintenance costs. The composite hull of this embodiment also possesses excellent buoyancy and stability, ensuring operational safety in complex sea conditions, and exhibits superior durability and strength to meet the demands of long-term, high-intensity operations. Moreover, its recyclability meets environmental requirements, providing an economical, efficient, and safe new solution for fisheries production.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A hull structure for a net-casting vessel with a composite hull structure, characterized in that, include: Hull (1), main mast (4), two net-laying booms (5), fishing net, multiple ribs (7), inner keel (8); The hull (1) is provided with two sets of support parts (2) and storage parts (3); the storage parts (3) are located between the two sets of support parts (2), and the storage parts (3) are provided with a number of fish cabins (31) connected in sequence; the support parts (2) are provided with a main load-bearing frame. The inner keel (8) is fixedly installed at the bottom of the hull (1), and the inner keel (8) is parallel to the direction of travel of the hull (1). The rib (7) is fixedly installed at the bottom inside the hull (1), the rib (7) is perpendicular to the inner keel (8), and the two ends of the rib (7) are respectively fixedly connected to the main load-bearing frame inside the two sets of support parts (2); The main mast (4) is fixed vertically to the bottom of the hull (1); A net-lifting machine (9) is fixedly installed on the top of the deck (13) of the hull (1); The two net-laying booms (5) are respectively installed on both sides of the hull (1); One end of the net-holding boom (5) is connected to the rotating part of the net-holding boom, and the rotating part of the net-holding boom is fixedly connected to the bulwark panel (14) of the hull (1). The other end of the net-holding boom (5) is connected to the net-holding boom rope (51). The fishing net is connected to the net-holding boom. The net-laying hoisting rope (51) is connected to the net-lifting machine (9) via the top of the main mast (4); When fishing begins, the net boom (5) can rotate horizontally and vertically around the end connected to the rotating part of the net boom.

2. The hull structure of a net-casting vessel with a composite hull structure according to claim 1, characterized in that, The rotating part of the tensioning rod includes a bushing (52) and a rod shaft (53); The bushing (52) is fixedly connected to the bulwark panel (14) of the hull (1); the boom shaft (53) is coaxially arranged inside the bushing (52). A limiting pin (54) is provided on the outer wall surface at the bottom of the boom shaft (53); the limiting pin (54) is located below the bushing (52); The top of the boom shaft (53) extends through the bulwark panel (14) of the hull (1), and a first connecting piece (55) is fixedly provided on the top of the boom shaft (53); the first connecting piece (55) is parallel to the axis of the boom shaft (53); The end of the tension net rod (5) connected to the rotating part of the tension net rod is provided with a second connecting piece (56); the second connecting piece (56) is parallel to the axis of the tension net rod (5); The first connecting piece (55) is rotatably connected to the second connecting piece (56), and the rotation axis is perpendicular to the first connecting piece (55).

3. The hull structure of a net-casting vessel with a composite hull structure according to claim 1, characterized in that, The main load-bearing frame includes a deck beam (21), a second rib (22), ribs (23), vertical supports (24), a deck girder (25), and side inner keels (26); The side inner keel (26) is fixedly installed at the bottom of the hull (1) and is parallel to the middle inner keel (8); The deck beams (21) and deck girders (25) are both fixedly installed at the bottom of the deck (13) of the hull (1), and the deck girders (25) are parallel to the inner keel (8); the deck beams (21) and deck girders (25) are perpendicular. The two ends of the vertical support (24) are respectively fixed perpendicularly to the deck girder (25) and the side inner keel (26); The second rib (22) is fixedly installed at the bottom inside the hull (1), and one end of the second rib (22) is vertically fixed to the side inner keel (26); The rib (23) is located on the side of the inner keel (26) away from the middle inner keel (8), and the two ends of the rib (23) are fixedly connected to the deck beam (21) and the second rib (22) respectively.

4. The hull structure of a net-casting vessel with a composite hull structure according to claim 1, characterized in that, The bottom plate (11), side plate (12), deck (13) and bulwark panel (14) of the hull (1) are all made of HDPE material.

5. The hull structure of a net-casting vessel with a composite hull structure according to claim 1, characterized in that, The main mast (4) is equipped with a fixed pulley (41); The net-laying boom rope (51) is connected to the net-lifting machine (9) and the net-laying boom (5) respectively via the fixed pulley (41) at the top of the main mast (4).

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