Anchor installation ship

Abstract

To provide an anchor installation ship capable of efficiently installing an anchor for mooring a large floating body structure.SOLUTION: The anchor installation ship 1 includes the hull 10, the first mooring device 30 that feeds out the first mooring line 50, to which the first anchor is connected, from the stern side of the hull 10, and the second mooring device 40 that feeds out the second mooring line 60, to which the second anchor is connected, from the bow side of the hull 10, and the first mooring line 50 has a length equal to or longer than that of the second mooring line 60.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an anchor-laying vessel. [Background technology]

[0002] Patent Document 1 listed below discloses a mooring method for a large floating structure (for example, a floating offshore wind power generation facility) that floats on the ocean. In this method, a chain and anchor of the length required for mooring are first loaded onto a work barge and transported to the installation area. Once the barge arrives at the installation area, the chain and anchor are lowered to the seabed using a chain lifter or the like, and the end of the chain is temporarily secured to a mooring buoy floating on the sea surface via a wire or the like.

[0003] A plurality of anchors are installed on the seabed around the planned installation location of the floating structure, and the chains are arranged in a manner that extends approximately radially from the planned installation location of the floating structure. Next, the floating structure is towed to the planned installation location, and each wire temporarily attached to each mooring buoy is pulled up, and the chains are fixed to the floating structure. This allows the floating structure to be catenarily moored in the installation area. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-39475 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the above-mentioned conventional technology, anchors must be installed one by one around the planned installation location of the floating structure, which requires the anchors and mooring lines to be reeled in and replaced multiple times, resulting in a problem of extremely long work times. Also, depending on the size of the floating structure, the anchors may need to have a large holding force (for example, 500 tons or more), and achieving this by bollard pulling using a ship towing the structure requires enormous horsepower, which is not practical.

[0006] The present invention has been made in consideration of the above problems, and has as its object to provide an anchor installation vessel that can efficiently install anchors for mooring large floating structures. [Means for solving the problem]

[0007] In order to solve the above problem, the anchor installation vessel of the first aspect of the present invention comprises a hull, a first mooring device that pays out a first mooring line to which a first anchor is connected from the stern side of the hull, and a second mooring device that pays out a second mooring line to which a second anchor is connected from the bow side of the hull, and the first mooring line has a length equal to or greater than that of the second mooring line.

[0008] A second aspect of the present invention is the anchor installation vessel of the first aspect, wherein the first mooring rope may have a length equal to or greater than the second mooring rope and equal to or less than twice the length of the second mooring rope.

[0009] A third aspect of the present invention is an anchor installation vessel of the first or second aspect, wherein the hull is provided with a bridge located closer to the bow than the second mooring device, and the bridge may have a through passage formed therein for passing the second mooring line.

[0010] A fourth aspect of the present invention is an anchor laying vessel according to any one of the first to third aspects, wherein the hull may have a stern roller provided on the stern side for guiding the first mooring line, and an ahead roller provided on the bow side for guiding the second mooring line.

[0011] A fifth aspect of the present invention is an anchor installation vessel according to any one of the first to fourth aspects, wherein the first mooring device comprises a first drum around which at least a portion of the first mooring line is wound, the second mooring device comprises a second drum around which at least a portion of the second mooring line is wound, and a shared winch that drives the first drum and the second drum.

[0012] A sixth aspect of the present invention is an anchor installation vessel according to any one of the first to fifth aspects, wherein the hull is provided with a bridge, the first mooring device is positioned aft of the bridge, and the second mooring device is positioned bow of the bridge.

[0013] A seventh aspect of the present invention is the anchor installation vessel of any one of the first to sixth aspects, wherein the first mooring device and the second mooring device may be provided at different heights.

[0014] According to an eighth aspect of the present invention, the anchor installation vessel of any one of the first to seventh aspects may further include a stopper for holding the second mooring rope. [Effects of the Invention]

[0015] According to the above aspect of the present invention, anchors for mooring large floating structures can be efficiently installed. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a side view of an anchor installation vessel according to a first embodiment. [Figure 2] FIG. 1 is a front view of an anchor installation vessel according to a first embodiment. [Figure 3] FIG. 2 is a plan view of the first deck according to the first embodiment. [Figure 4] FIG. 2 is a plan view of the second deck according to the first embodiment. [Figure 5] FIG. 2 is an explanatory diagram of an anchor installation method according to the first embodiment. [Figure 6]FIG. 2 is an explanatory diagram of an anchor installation method according to the first embodiment. [Figure 7] FIG. 2 is an explanatory diagram of an anchor installation method according to the first embodiment. [Figure 8] FIG. 2 is an explanatory diagram of an anchor installation method according to the first embodiment. [Figure 9] FIG. 2 is an explanatory diagram of an anchor installation method according to the first embodiment. [Figure 10] FIG. 2 is an explanatory diagram of an anchor installation method according to the first embodiment. [Figure 11] FIG. 2 is an explanatory diagram of an anchor installation method according to the first embodiment. [Figure 12] FIG. 2 is an explanatory diagram of an anchor installation method according to the first embodiment. [Figure 13] FIG. 10 is a side view of the anchor installation vessel according to the second embodiment. [Figure 14] FIG. 10 is a side view of the anchor installation vessel according to the third embodiment. [Figure 15] FIG. 10 is a side view of the anchor installation vessel according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, the anchor installation vessel of this embodiment will be described with reference to the drawings.

[0018] (First embodiment) Fig. 1 is a side view of the anchor installation vessel 1 according to the first preferred embodiment. Fig. 2 is a front view of the anchor installation vessel 1 according to the first preferred embodiment. As shown in Fig. 1, the anchor installation vessel 1 includes a hull 10, a bridge 20, a first mooring device 30, and a second mooring device 40. The anchor installation vessel 1 of this embodiment is suitable for use when mooring a large floating structure such as an offshore wind power generation float. Note that the floating structure is not limited to an offshore wind power generation float.

[0019] In the following explanation, an XYZ Cartesian coordinate system is set, and the positional relationships of each component are sometimes explained with reference to this XYZ Cartesian coordinate system. As shown in the figure, the X-axis direction is set to the fore-and-aft direction of the hull 10. The Y-axis direction is set to the left-and-right direction of the hull 10. The Z-axis direction is set to the up-and-down direction of the hull 10. The +X side is the bow side of the hull 10. The -X side is the stern side of the hull 10.

[0020] The hull 10 comprises a first deck 11 and a second deck 12 that is higher than the first deck 11. The first deck 11 is provided from the center of the hull 10 in the longitudinal direction to the stern of the hull 10. A first mooring device 30 is provided on the first deck 11. In addition, a stern roller 13 is provided on the stern side (-X side) of the hull 10.

[0021] The second deck 12 is provided from the center of the hull 10 in the longitudinal direction to the bow of the hull 10. A bridge 20 and a second mooring device 40 are provided on the second deck 12. In addition, an ahead roller 14 is provided on the bow side (+X side) of the hull 10.

[0022] The bridge 20 is provided with an accommodation area including a wheelhouse. A passageway 21 is formed in the bridge 20, penetrating it in the fore-and-aft direction. As shown in FIG. 2, the passageway 21 is formed in the center of the lower part of the bridge 20 in the left-right direction. The passageway 21 is formed below (on the -Z side of) the accommodation area of ​​the bridge 20.

[0023] FIG. 3 is a plan view of the first deck 11 according to the first embodiment. As shown in Figure 3, the first mooring device 30 is arranged behind the bridge 20. The first mooring device 30 pays out a first mooring rope 50 to which a first anchor 51 is connected from the stern side (-X side) of the hull 10.

[0024] The first mooring rope 50 is guided by a stern roller 13 provided on the stern side (-X side) of the hull 10. The two-dot chain line in Figure 3 shows the first anchor 51 placed on the first deck 11 before being cast into the sea.

[0025] The first mooring device 30 includes a first drum 31 around which at least a portion of the first mooring rope 50 is wound, and a first winch 32 that drives the first drum 31. The first winch 32 rotates the first drum 31 to pay out and reel in the first mooring rope 50. Note that the first mooring device 30 may include not only one first drum 31 and one first winch 32, but also a plurality of drums and winches.

[0026] The first mooring line 50 includes, for example, at least one of a chain, a wire, and a rope. Depending on the specifications of the first mooring line 50, the first mooring device 30 may also be equipped with, for example, a chain stopper (not shown) for securing the chain, or a crane (not shown) for changing the wire, rope, etc. The first mooring device 30 may also be equipped with various other devices for handling the first mooring line 50 and the first anchor 51. Note that at least some of the various devices may be used for work other than mooring work (for example, a locking arm may be used for towing work).

[0027] 4 is a plan view of the second deck 12 according to the first embodiment. Note that FIG. 4 corresponds to the view taken along the line IV-IV shown in FIG. As shown in Figure 4, the second mooring device 40 is arranged behind the bridge 20. The second mooring device 40 pays out a second mooring rope 60 to which a second anchor 61 is connected from the bow side (+X side) of the hull 10.

[0028] The second mooring line 60 passes through a passageway 21 provided in the bridge 20 and is guided by an ahead roller 14 provided on the bow side (+X side) of the hull 10. The two-dot chain line in Figure 4 shows the second anchor 61 placed on the second deck 12 before being dropped into the sea.

[0029] The second mooring device 40 includes a second drum 41 around which at least a portion of the second mooring rope 60 is wound, and a second winch 42 that drives the second drum 41. The second winch 42 rotates the second drum 41 to pay out and reel in the second mooring rope 60. The second winch 42 may be configured by combining a traction winch that can maintain a certain braking function with a winch that has a winding function. The second mooring rope 60 includes, for example, at least one of a chain, a wire, and a rope.

[0030] The second anchor 61 is preferably a reaction anchor that can be retrieved and reused on the hull 10. As a result, while the number of sets of mooring ropes and anchors that need to be mounted on the hull 10 would require, for example, a dozen or so sets of first mooring ropes 50 and first anchors 51, only one set of second mooring ropes 60 and second anchors 61 is required. Note that in the second mooring device 40, if the mooring ropes and anchors are replaced in the same way as in the first mooring device 30, multiple sets of second mooring ropes 60 and second anchors 61 may be mounted.

[0031] As will be described later, the first mooring device 30 drops the second anchor 61 while keeping the first anchor 51 connected. Therefore, the first mooring line 50 has a length equal to or greater than the second mooring line 60. Specifically, the first mooring line 50 has a length equal to or greater than the second mooring line 60, but is not more than twice as long as the second mooring line 60. Note that the "length of the mooring line" refers to the length of the first mooring line 50 to the second mooring line 60 that can be let out from the hull 10 and the first mooring device 40 to the second mooring device 40.

[0032] Next, an anchor installation method using the anchor installation vessel 1 having the above configuration will be described with reference to FIGS. Figures 5 to 12 are explanatory diagrams of the anchor installation method according to the first embodiment. Note that reference symbol P1 in Figures 5 to 12 indicates the planned installation area of ​​the floating structure.

[0033] In this method, first, a first anchor 51 is dropped at a position a mooring radius away from the planned installation area P1 of the floating structure, as shown in Fig. 5. The first anchor 51 is connected to one end of the chain 50a of the first mooring rope 50, and is dropped toward the seabed 100 together with the chain 50a.

[0034] Next, in this method, as shown in Figure 6, the hull 10 is moved toward the planned installation area P1 of the floating structure while letting out the first mooring rope 50. This completes the laying of the chain 50a on the seabed 100. The wire 50b of the first mooring rope 50 is connected to the other end of the chain 50a, and the wire 50b is let out after the chain 50a is let out.

[0035] Next, in this method, the hull 10 is moved past the planned installation area P1 of the floating structure to a position that is a distance equal to the mooring radius, as shown in Figure 7. In other words, the hull 10 moves a distance that is approximately twice the mooring radius.

[0036] Next, in this method, as shown in Fig. 8, a second anchor 61 is dropped at a position that is a mooring radius away from the planned installation area P1 of the floating structure. In other words, the second anchor 61 is dropped at a position that is approximately point-symmetrical to the first anchor 51 in a plan view, with the planned installation area P1 of the floating structure as the center.

[0037] Next, in this method, as shown in Figure 9, the hull 10 is moved toward the planned installation area P1 of the floating structure while letting out the second mooring rope 60. Also, while letting out the second mooring rope 60, the first mooring rope 50 is reeled in.

[0038] Next, in this method, as shown in Figure 10, a bollard pull is performed, in which a holding force is applied in advance to the first anchor 51 using the propulsion force of the hull 10. As a result, a holding force of, for example, about 300 tons is applied to the first anchor 51. Also, at the bow side, the second mooring device 40 reels in the second mooring rope 60, and the second winch 42 applies a holding force to the second anchor 61 similar to that of the first anchor 51.

[0039] Next, in this method, as shown in Figure 11, the first mooring device 30 reels in the first mooring rope 50, and the first winch 32 applies a large holding force to the first anchor 51. At this time, the second mooring device 40 brakes and holds the second mooring rope 60. For example, if the reeling capacity of the first mooring device 30 is about 500 tons, a holding force of about 500 tons can be applied to the first anchor 51. Note that if the first mooring device 30 is equipped with two winches, and two wires 50b are hooked to the two winches and reeled in 500 tons each, a holding force of about 1000 tons can be applied to the first anchor 51.

[0040] At this time, if the drag distance of the second anchor 61 becomes long, it is advisable to adjust the length of the second mooring line 60 by reeling in the second mooring line 60 with the second mooring device 40 while letting out the first mooring line 50 from the first mooring device 30, as shown in Figure 12. Then, you can return to the operation shown in Figure 11.

[0041] Once a predetermined holding force has been applied to the first anchor 51, the first mooring line 50 is detached from the first mooring device 30 and connected to a mooring buoy (not shown). Then, while reeling in the second mooring line 60, the hull 10 is moved to the position where the second anchor 61 is deployed, and the second anchor 61 is retrieved.

[0042] The hull 10 is then moved to another position that is a mooring radius away from the planned installation area P1 of the floating structure. Thereafter, the steps shown in Figures 5 to 12 are repeated for each set of first mooring lines 50 and first anchors 51 to be installed. After that, the floating structure (not shown) is towed to the planned installation area P1 of the floating structure, and the wires 50b temporarily attached to the mooring buoys are pulled up, and the chains 50a are fixed to the floating structure. This allows the floating structure to be moored in the planned installation area P1.

[0043] As described above, the anchor installation vessel 1 according to this embodiment comprises the hull 10, the first mooring device 30 that pays out the first mooring line 50 connected to the first anchor 51 from the stern side of the hull 10, and the second mooring device 40 that pays out the second mooring line 60 connected to the second anchor 61 from the bow side of the hull 10, the first mooring line 50 being longer than the second mooring line 60. With this configuration, the second anchor 61 can be dropped after passing through the planned installation area P1 of the floating structure while the first anchor 51 remains connected. This allows the front and rear first mooring lines 50 and second mooring lines 60 to be tug-and-tug near the planned installation area P1 of the floating structure without changing the first mooring line 50, thereby applying a large holding force to the first anchor 51, thereby significantly shortening the construction period. Furthermore, with this configuration, by adjusting the length of the chain 50a based on the mooring radius of the floating structure, it is possible to apply a large holding force to the first anchor 51 while simultaneously determining the mooring position of the floating structure. As described above, according to this embodiment, anchors for mooring large floating structures can be efficiently installed.

[0044] Furthermore, in this embodiment, the first mooring line 50 has a length equal to or greater than the second mooring line 60, but not greater than twice the length of the second mooring line 60. With this configuration, the hull 10 can pass through the planned installation area P1 of the floating structure while keeping the first anchor 51 connected, and can move a distance that is sufficiently less than twice the mooring radius of the floating structure.

[0045] Furthermore, in this embodiment, the hull 10 is equipped with a bridge 20 located closer to the bow than the second mooring device 40, and the bridge 20 is formed with a through passage 21 through which the second mooring ropes 60 pass. With this configuration, the second mooring device 40 can be located behind the bridge 20, eliminating the need to ensure a large deck space on the bow side of the hull 10. Furthermore, the center of gravity of the hull 10 is more stable than if the second mooring device 40 were located on the bow side.

[0046] In this embodiment, the hull 10 has a stern roller 13 provided on the stern side to guide the first mooring line 50, and an ahead roller 14 provided on the bow side to guide the second mooring line 60. With this configuration, the first mooring line 50 can be guided on the stern side, and the second mooring line 60 can be guided on the bow side.

[0047] In this embodiment, the first mooring device 30 and the second mooring device 40 are provided at different heights (see Figure 1). This configuration allows the first mooring device 30 and the second mooring device 40 to be positioned closer together than if they were positioned at the same height, thereby making it possible to reduce the size of the hull 10. In this case, for example, as shown in Figure 1, the first mooring device 30 and the second mooring device 40 can be positioned in the center in the fore-and-aft direction. Note that the center in the fore-and-aft direction refers to the central portion when the hull 10 is divided into three equal parts in the fore-and-aft direction.

[0048] (Second embodiment) Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0049] FIG. 13 is a side view of the anchor installation vessel 1A according to the second preferred embodiment. As shown in Figure 13, in the second embodiment, the first mooring device 30 is arranged aft of the bridge 20, and the second mooring device 40 is arranged bow of the bridge 20. With this configuration, anchors can be installed in the same way as in the first embodiment. Note that with this configuration, the deck space forward of the bridge 20 becomes narrower to install the second mooring device 40, but there is no need to provide a gangway 21 in the bridge 20 as in the first embodiment.

[0050] (Third embodiment) Next, a third embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0051] FIG. 14 is a side view of an anchor installation vessel 1B according to the third preferred embodiment. As shown in Figure 14, the anchor installation vessel 1B of the third embodiment is equipped with a shared winch 34 that drives the first drum 31 of the first mooring device 30 and the second drum 41 of the second mooring device 40. With this configuration, anchors can be installed in the same way as in the first embodiment. Furthermore, with this configuration, the provision of the shared winch 34 allows the number of winches to be reduced compared to the first and second embodiments.

[0052] (Fourth embodiment) Next, a fourth embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiments will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0053] FIG. 15 is a side view of an anchor installation vessel 1C according to the fourth preferred embodiment. As shown in FIG. 15, the anchor installation vessel 1C of the fourth embodiment is provided with a stopper 70 (e.g., a wire stopper) that holds the second mooring line 60. With this configuration, the anchor can be installed in the same way as in the first embodiment. Specifically, as shown in FIG. 10, when the front and rear first mooring lines 50 and second mooring lines 60 are tug-and-tug near the planned installation area P1 of the floating structure, the second mooring device 40 brakes and holds the second mooring line 60, but this role can be taken over by the stopper 70. With this configuration, the traction winch that can maintain a certain braking function in the second mooring device 40 can be replaced with the stopper 70, thereby simplifying the configuration of the second mooring device 40.

[0054] While preferred embodiments of the present invention have been described and illustrated, it should be understood that they are illustrative of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the present invention should not be deemed limited by the foregoing description, but rather by the scope of the claims.

[0055] In addition, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate, without departing from the spirit of the present invention. [Explanation of symbols]

[0056] 1. Anchor laying vessel 1A Anchor laying vessel 1B Anchor laying vessel 1C Anchor laying vessel 10 Hull 11 Deck 1 12 Deck 2 13 Stern Roller 14 Ahead Roller 20 Bridge 21 Passage 30 No. 1 Mooring Device 31 First Drum 32 No. 1 winch 34 Common winch 40 Second Mooring Device 41 Second Drum 42 No. 2 winch 50 1st mooring line 50a chain 50b wire 51 First Anchor 60 Second mooring line 61 Second Anchor 70 Stopper 100 Undersea P1 planned installation area

Claims

1. The hull and a first mooring device that pays out a first mooring rope to which a first anchor is connected from the stern side of the hull; a second mooring device that pays out a second mooring rope to which a second anchor is connected from the bow side of the hull, The first mooring rope has a length equal to or greater than the second mooring rope. Anchor laying vessel.

2. The first mooring rope has a length equal to or greater than the second mooring rope and equal to or less than twice the length of the second mooring rope.

2. An anchor laying vessel according to claim 1.

3. the hull includes a bridge provided on the bow side of the second mooring device, The bridge has a passageway formed therein through which the second mooring rope passes.

3. An anchor laying vessel according to claim 1 or 2.

4. The hull is a stern roller provided on the stern side and guiding the first mooring rope; an ahead roller provided on the bow side and guiding the second mooring rope; 3. An anchor laying vessel according to claim 1 or 2.

5. the first mooring device includes a first drum around which at least a portion of the first mooring rope is wound; the second mooring device includes a second drum around which at least a portion of the second mooring rope is wound; a common winch that drives the first drum and the second drum; 3. An anchor laying vessel according to claim 1 or 2.

6. The hull includes a bridge; the first mooring device is disposed aft of the bridge, The second mooring device is arranged on the bow side of the bridge.

3. An anchor laying vessel according to claim 1 or 2.

7. The first mooring device and the second mooring device are provided at different heights.

3. An anchor laying vessel according to claim 1 or 2.

8. a stopper for holding the second mooring rope; 3. An anchor laying vessel according to claim 1 or 2.

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