Workboat with Spud and Method of Operating It

Abstract

This invention provides a spud-equipped workboat and its operating method that eliminate the need for large generators mounted on workboats such as grab dredgers and crane ships, thereby significantly reducing fuel consumption. [Solution] In a workboat equipped with a spud for mooring a workboat, the vessel comprises a columnar spud 1 thrust from the hull into the seabed, a first hydraulic engine 31 or first generator 32 installed on the hull D for raising and lowering the spud and moving the workboat, an accumulator 41 that stores hydraulic fluid by converting the output energy of the first hydraulic engine into fluid energy using a first hydraulic pump 33, or the output energy of the first generator into fluid energy using a first electric hydraulic pump 35, and a supply pipe 42 that supplies the hydraulic fluid from the accumulator to the hydraulic motor 25 of a winch 21 that raises and lowers the spud 1. The hydraulic motor 25 is rotated solely by the energy of the hydraulic fluid from the accumulator, causing the wire 22 to be wound up by the winch 21, thereby raising the spud 1 thrust into the seabed.

Description

Technical Field

[0001] The present invention relates to a spud-equipped work vessel for mooring a work vessel during dredging operations and the like, and an operating method therefor.

Background Art

[0002] As work vessels used for offshore construction such as construction of port facilities and securing water depth of navigation channels, there are spud-equipped work vessels such as dredgers and crane vessels provided with spuds for mooring the hull in the work sea area. Most spud-equipped work vessels mount a crane on a square barge, and mount mooring devices such as a maneuvering winch and a spud device at appropriate positions on the deck. They are operated by electric motors and hydraulic motors. Hydraulic devices use electric hydraulic pumps mounted in the hull, which require the largest amount of power among the devices mounted on the work vessel, and large generators are installed to operate these devices. In the case of a grab dredger, since the work involves movement using spuds, a large flow rate of hydraulic working fluid is required when the spuds are lifted, a plurality of large-capacity hydraulic pumps for supplying the fluid are mounted, and a further large generator is mounted (Table 1).

[0003]

Table 1

[0004] For example, 30 m 3 class large dredger is equipped with a large generator with a capacity of 300 to 610 KVA as the main generator, and the generator equipped with a large diesel engine keeps operating continuously during operation in the work site sea area. For details, in the case of dredger 27K, listed at the bottom of Table 1, it is equipped with two wire-type spuds 1 and a walking spud 1B, also called a kick spud, as mooring equipment. To drive these devices, it is equipped with three 75kW second electric hydraulic pumps 93 931, 932, and 933 (Figures 11 and 13). To operate these three pumps 93 almost simultaneously, a large 400KVA generator is installed as the main generator 91. In addition, two 150KVA generators 92 are installed as berthing generators, one of which is used when berthing. Furthermore, in dredgers of other companies, including 27K, the main generator 91 continues to operate even during the dredging process in preparation for the next movement process. This results in a large surplus of power of over 300kW, and also presents problems such as increased fuel consumption and unnecessary CO2 emissions. Incidentally, this large power capacity is required for a short period of about 6 minutes when moving from one work area to another, as shown in Figure 12, after a 30-minute operation at one work area, although this depends on the water depth at the site. The reason for continuing to operate the large-capacity generator, the main generator 91, for just 6 minutes of high power demand within a 36-minute cycle is that the switching operation to the auxiliary generator, the anchoring generator 92, is complicated, and during power switching, the conventional onboard electrical system is as shown in Figure 13 (the onboard equipment configuration is shown in Figure 14), resulting in a momentary power outage. In this context, the applicant has been working to conserve energy in work vessels such as dredgers and has proposed several inventions (for example, Patent Documents 1 and 2), but none of them involved modifying the main generator 91. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 6819997 [Patent Document 1] Patent No. 6890343 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0006] Furthermore, the aforementioned problem also created another problem. Workboats equipped with the main generator 91 of the large generator would switch to the anchoring generator 92 after the end of the day's work, shutting down the main generator 91 and transitioning to an anchored state. However, many ships used only one 125KVA generator as the anchoring generator 92 (Table 1). The power demand while anchored consists of lighting, air conditioning, and water pumps for living quarters, so the anchoring generator 92 could be met with a capacity of about 75KVA, but some ships were equipped with two 125KVA generators and operated in parallel. This was because the 250KVA capacity was intended to serve as a backup in case the main generator 91 failed. Therefore, there was a problem of significant surplus electricity being generated during dredging operations and even while the ship was docked, as well as the consumption of unnecessary fuel.

[0007] The present invention aims to solve the above problems by providing a spud-equipped work vessel and its operating method that eliminates the need for large generators mounted on spud-equipped work vessels such as grab dredgers and crane ships, thereby significantly reducing fuel consumption. [Means for solving the problem]

[0008] To achieve the above objective, a first aspect of the present invention is a workboat equipped with a spud for mooring a workboat, comprising: a columnar spud thrust from the hull into the seabed; a first hydraulic engine or first generator installed on the hull for raising and lowering the spud and moving the workboat; an accumulator that stores hydraulic fluid by converting the output energy of the first hydraulic engine into fluid energy using a first hydraulic pump, or the output energy of the first generator into fluid energy using a first electric hydraulic pump; and a supply pipe that supplies the hydraulic fluid from the accumulator to a hydraulic motor of a winch for raising and lowering the spud, wherein the hydraulic motor is rotated solely by the energy of the hydraulic fluid from the accumulator, causing the wire to be wound up by the winch, thereby raising the spud thrust into the seabed. A second aspect of the present invention is characterized in that, in the first aspect, the output energy of the first hydraulic engine is supplied by the first hydraulic pump, or the output energy of the first generator is supplied by the first electric hydraulic pump, or the output energy of the first hydraulic engine is supplied by the first hydraulic pump. A third aspect of the present invention is characterized in that, in the first or second aspect, a main generator is further provided that supplies power to the lifelines and control system, power for work under mooring conditions, and hydraulic power for the second hydraulic pump for raising and lowering the spud and moving the workboat. A fourth aspect of the present invention relates to a method for operating a workboat equipped with a spud for mooring the workboat, comprising: a columnar spud thrust from the hull into the seabed; a first hydraulic engine or first generator installed on the hull for raising and lowering the spud and moving the workboat; an accumulator that stores hydraulic fluid by converting the output energy of the first hydraulic engine into fluid energy using a first hydraulic pump, or the output energy of the first generator into fluid energy using a first electric hydraulic pump; and a hydraulic motor of a winch that raises and lowers the spud from the accumulator. The method for operating a workboat with a spud is characterized by comprising a supply pipe for supplying oil, operating the first hydraulic engine or the first generator during the mooring operation of the workboat to store hydraulic fluid in the accumulator, and after the mooring operation of the workboat, raising the spud for mooring that has been driven into the seabed using only the fluid energy of the hydraulic fluid stored in the accumulator, and further supplying mechanical energy to move the workboat from the work site where the spud is driven into the sea to the next work site in the work area. [Effects of the Invention]

[0009] The spud-equipped workboat and its operating method of the present invention, during main operations such as dredging and excavation, which have longer working times compared to the movement time, accumulates and stores hydraulic fluid in an accumulator, and raises the spud using only that energy. This not only eliminates the need for large generators with high power capacity during the workboat movement phase, but also has a significant effect on energy conservation. [Brief explanation of the drawing]

[0010] [Figure 1]It is a schematic electrical system diagram of a pressure accumulation system in one embodiment of a working vessel with spuds and an operating method thereof. [Figure 2] It is a schematic hydraulic system diagram of an electric pressure accumulation system. [Figure 3] It is a schematic configuration diagram of an electric pressure accumulation system device according to Fig. 2. [Figure 4] They are respective explanatory diagrams of during dredging work, walking spud raising, walking spud tilting, and walking spud lowering. [Figure 5] They are respective explanatory diagrams of fixed spud raising, walking spud tilting, fixed spud lowering, and walking spud raising. [Figure 6] They are respective explanatory diagrams of completion of movement achieved by tilting of the walking spud to a vertical position and lowering of the walking spud. [Figure 7] It is an explanatory relationship diagram that illustrates, with the horizontal axis as a time axis, changes in energy consumption amount in a dredging step and a movement step, and changes in accumulated pressure energy amount and consumed energy amount in an accumulator. [Figure 8] It is a schematic hydraulic system diagram of an engine-type pressure accumulation system. [Figure 9] It is a schematic configuration diagram of an engine-type pressure accumulation system device. [Figure 10] It is a schematic hydraulic system diagram in which the present pressure accumulation system is added to a conventional dredger hydraulic system. [Figure 11] It is a schematic hydraulic system diagram of a conventional dredger. [Figure 12] It is a flow chart of each step in dredging work. [Figure 13] It is a conventional on-board electrical system diagram. [Figure 14] It is a schematic configuration diagram of ordinary equipment in a conventional dredger. DESCRIPTION OF EMBODIMENTS

[0011] Hereinafter, the working vessel with spuds and the operating method thereof according to the present invention will be described in detail. Figures 1 to 10 show one embodiment of the spud-equipped workboat and its operating method according to the present invention applied to a dredger. Figure 1 is an electrical system diagram of the pressure accumulator system, Figure 2 is a hydraulic system diagram in an electrically operated pressure accumulator system, Figure 3 is a configuration diagram of the electrical pressure accumulator system equipment, and Figures 4 to 6 are explanatory diagrams of the dredging process and the movement process using spuds and walking spuds. Figure 7 is an explanatory diagram showing the relationship between the change in energy consumption in each process of dredging and spud operation, and the change in the amount of pressure accumulated and energy consumed in the accumulator, with the horizontal axis being the time axis. Figure 8 is a hydraulic system diagram in an engine-type pressure accumulator system, Figure 9 is a configuration diagram of the engine-type pressure accumulator system equipment, and Figure 10 is a hydraulic system diagram in which the pressure accumulator system of the present invention is added to a conventional dredger hydraulic system. Note that in order to make the drawings easier to understand, the essential parts of the invention are emphasized in each figure, and parts not directly related to the present invention are simplified or omitted. The symbols in the lower right frame of Figure 14 also apply to Figures 3 and 9.

[0012] (1) Workboat with spud A spud-equipped workboat is a workboat such as a dredger or crane vessel equipped with a spud 1 for mooring the workboat. The spud-equipped workboat in this embodiment is a dredger as shown in Figures 1 to 3, corresponding to the size of dredger 27K listed at the bottom of Table 1. Conventional onboard electrical systems had each power load connected to a single line, and the generators supplying the power were switched for use (Figure 13), but here, an electrical system for the pressure accumulation system with divided roles as shown in Figure 1 is adopted.

[0013] The right side of Figure 1 shows the lifeline and control system, which includes electricity used for all aspects of the crew's daily lives, such as onboard lighting, air conditioning, and drinking water pumps, as well as electricity for the construction management system and the remote control panels for each winch 21. The power source for this is a 75 kVA mooring generator 52. The center of Figure 1 shows the work power system, which includes electricity used during work, such as electricity for cranes, engine cooling systems, and general-purpose water pumps, excluding electricity for hydraulic pumps. The power source for this is a 100 kVA work generator 51. The left side of Figure 1 shows the hydraulic power system, which uses only the fluid energy of the hydraulic fluid stored in the accumulator 41 to supply the mechanical energy needed to raise the mooring spud 1 that is driven into the seabed B. Furthermore, in this embodiment, the first electric hydraulic pump 35 also provides the power to move the hull using the walking spud 1B and to drive the tilting cylinder 29 in the work area. As a power source, the first generator 31 (and the first electric hydraulic pump 35) can be replaced with the first hydraulic engine 31 (and the first hydraulic pump 33) shown below the white double arrow in Figure 1, but here we use the 100 KVA first hydraulic generator 32.

[0014] The workboat with a spud is equipped with a spud 1, a first generator 32, an accumulator 41, and a supply pipe 42 on the hull D.

[0015] The spud 1 is a heavy, cylindrical metal body with a circular or rectangular cross-section that is driven from the hull D into the seabed B to stop the movement of the work vessel. As shown in Figure 4, the spud 1 consists of a fixed spud 1, which is a fixed spud device used to position the work vessel (dredger), and a walking spud 1B, which is a walking spud device used to move the hull D. In this invention, the spud refers to the fixed spud 1. For example, in a dredging area, the spud 1 is driven into the seabed B and fixed in place, the work vessel is moored to it, and dredging work is carried out. Once the work is completed, the spud 1 is lifted up with the lifting device 2, then the hull is moved using the walking spud 1B, the spud 1 is driven into the seabed B again and fixed in place to stop the work vessel, and then dredging work is carried out sequentially (Figures 4 to 6). The lifting device 2 includes a sled 20, a winch 21, a wire 22, and a hydraulic motor 25. The hydraulic motor 25 rotates and the winch 21 winds up the wire 22, causing the spud 1, which is driven into the seabed B in Figure 4, to rise. During the dredging operation, the first generator 32, which is the power source, is operated to supply hydraulic fluid, which has been pressurized in the accumulator 41, to the hydraulic motor 25, thereby raising the spud 1 (details will be described later).

[0016] The lifting device 2 is a device that has its main part attached to the hull D and can move the spud 1 in the vertical direction for lifting and lowering. This embodiment is a suspension type lifting device 2 comprising a turret 20 which is the main part erected on the hull D, and a winch 21 which suspends the spud 1 at the tip of the wire 22 via a head sheave 23 provided on the turret and winds up the base end of the wire 22. The tip of the wire 22 is attached to the spud 1, while the base end of the wire 22 is attached to the winch 21 via a head sheave 23 attached to the top of the turret 20, and the spud 1 is raised to the required height by winding up the winch 21. The tip of the wire 22 is attached to a cursor (not shown) fixed to the spud 1 with a pin or the like. The upward arrows related to the white double arrows in Figure 3 represent the movement of the wire 22 and the lifting movement of the spud 1 due to the winding up of the winch 21. Furthermore, when the spud 1 is lifted and held, releasing the spud locking mechanism (not shown) allows the spud 1 to fall under its own weight through the through hole D1 provided in the hull D, as indicated by the downward arrow related to the white double arrow (Figure 5, 7), and be driven into the seabed B.

[0017] The first generator 32 is installed on the hull D and is the power source for raising and lowering the spud and moving the workboat. The first generator 32 supplies mechanical energy for raising the spud 1 and for moving the hull using the walking spud 1B. In this invention, by providing an accumulator 41 and supplying power in accordance with the timing and capacity of the power demand (details described later), the first generator 32, which is equipped with a diesel engine and has a capacity of 100 kVA, can handle the load, and this first generator 32 is adopted. Compared to the capacity of the conventional main generator 91, which has a capacity of 400 kVA as described in Figure 14 and Table 1, this is significantly smaller, about one-quarter the capacity. The starting, stopping, and power-on of the first generator 32 are automated. The key switch contacts and the solenoid for engine speed control are external contacts and controlled by a programmable logic controller (PLC). The power-on magnetic switch is controlled in the same way.

[0018] The accumulator 41 is a pressure accumulator that stores hydraulic fluid obtained by converting the output energy of the first generator 32 into fluid energy using the first electric hydraulic pump 35. Energy from the first generator 32 is converted into hydraulic fluid by the first electric hydraulic pump 35, and the hydraulic fluid is stored in the accumulator 41 via the discharge side hydraulic piping 342 of the first electric hydraulic pump 35. The accumulator 41 has a capacity to store 2,500 L of hydraulic fluid, which is necessary for the movement process by the spud 1 and walking spud 1B described later. During the 30-minute dredging operation, the 100 KVA first hydraulic generator 32, which is smaller than the conventional main generator 91, is started to activate the first electric hydraulic pump 35, thereby accumulating the necessary amount of hydraulic fluid in the accumulator 41. The hydraulic fluid passing through the discharge hydraulic piping 342 from the first electric hydraulic pump 35 is pressurized in the accumulator 41 via the mode switching valve and check valve 73, as shown by the white arrows in Figure 2. Once pressurization is complete, the first hydraulic generator 32 is stopped. This series of operations is automated by a programmable logic controller (PLC). The hydraulic fluid accumulated in the accumulator 41 then passes through the supply pipe 42, as shown by the black arrow in Figure 2, to supply the mechanical energy necessary to raise the spud 1 and to move the hull using the walking spud 1B.

[0019] The supply pipe 42 is a pressure-resistant flow path forming pipe that supplies hydraulic fluid from the accumulator 41 to the hydraulic motor 25 of the winch 21 that raises and lowers the spud 1. The hydraulic fluid accumulated in the accumulator 41 supplies the pressure and flow rate of the hydraulic fluid to the hydraulic motor 42 through the supply pipe 42. The supply pipe 42 connects the accumulator 41, the three hydraulic motors 251, 252, and 253, and the tilting cylinder 29 of the walking spud 1B via a solenoid valve 79, a variable throttle valve 74, and a control valve 72 (Figure 2). In Figure 2, the two hydraulic motors 251 and 252 on the right are responsible for winding up the spud 1 with the winch 21 (Figure 3), while the single hydraulic motor 253 on the left is responsible for winding up the walking spud 1B with the winch 21.

[0020] Reference numeral 8 denotes a dredger equipped on a dredger, which is fitted with a dredging engine 81, a grab bucket 86, a jib 87, and a sheave 88 (Figure 3). The jib 87 is a boom that extends diagonally upward from the rotating body of the dredger 8, with its base end attached to the rotating body, in order to lift the grab bucket 86 that has grasped the sediment. A sheave 88, which is a guide vehicle that changes the direction of the wire 83 in order to hoist up and down the bucket 86, is attached to the tip of the jib 87, enabling dredging work. In the diagram, reference numeral 321 denotes a hydraulic power line, reference numeral 341 denotes a hydraulic piping on the pump suction side, reference numeral 349 denotes a hydraulic return piping for the hydraulic fluid, reference numeral 38 denotes a hydraulic fluid tank, reference numeral 511 denotes a power line for work, reference numeral 521 denotes a power line for lifelines and control systems, reference numeral 75 denotes instrumentation wiring, and reference numeral S denotes the sea surface.

[0021] In this manner, the hydraulic fluid stored in the accumulator 41 is supplied into the supply piping 42 based on a command from the control means 71, and from the accumulator 41, via the solenoid valve 79, the variable throttle valve 74, and then the control valve 72, it supplies mechanical energy to rotate the hydraulic motor 25 or operate the tilting cylinder 29. The desired workboat with a spud 1 is created by using only the energy from the hydraulic fluid from the accumulator 41 to rotate the hydraulic motors 251 and 252, which in turn wind up the wire 22 with the winch 21, thereby raising the spud 1 that is driven into the seabed, and further activating the hydraulic motor 253 and tilting cylinder 29 to move the hull using the walking spud 1B.

[0022] Next, we will explain one method of operating the spud-equipped workboat described above. When the dredging vessel arrives at the dredging area, it moors itself by dropping the spud 1 under its own weight through a through hole D1 in the hull D and driving it into the seabed. Next, dredging work is carried out as shown in Figures 4 and 7 [1. Dredging work in progress]. Dredging work is a dredging process, also called an excavation process, using a dredger 8, and takes about 30 minutes as shown in Figure 12. The present invention utilizes this long time while the work vessel is moored to store the required amount of hydraulic fluid in the accumulator 41. This is possible even with the electric first generator 32, which is significantly smaller than the main generator 91.

[0023] In detail, as shown in Figure 2, based on a command from the control means 71, the first generator 32 and the first electric hydraulic pump 35 are started. The energy from the first generator 32, which is the power source, is converted into fluid energy of hydraulic fluid by the first electric hydraulic pump 35 and stored as hydraulic fluid in the accumulator 41. From the first electric hydraulic pump 35, the hydraulic fluid is sent to the accumulator 41 via the discharge side hydraulic piping 342, through the mode switching valve and check valve 73. When the required amount of hydraulic fluid is accumulated in the accumulator 41, the fluid supply is automatically stopped. The bottom row of Figure 7 schematically illustrates the change in the amount of hydraulic fluid stored. If the dredging process takes 30 minutes, the mechanical energy required for the raising of the spud 1 and the movement of the hull by the walking spud 1B during the moving process, as shown by the horizontal axis time in the same figure, can be sufficiently accumulated in the accumulator 41 as hydraulic fluid.

[0024] During the [1. Dredging Operation], the drilling takes about 30 minutes per stroke for a single layer, and the time required for the movement phase is about 5-6 minutes. However, in the case of double-layer drilling or deep drilling, the time for the movement phase remains the same, but the time for the dredging phase becomes even longer. The dredging phase and the movement phase do not overlap. The first electric hydraulic pump 35 and the first hydraulic pump 33 shown in Figure 8 (described later) operate only during the movement phase. After completing one movement phase and fixing the hull D to the seabed with the spud 1, they remain idle until the next movement phase. Incidentally, while the dredging process shown in Figures 4 and 7, [1. Dredging in progress], takes 30 minutes, the subsequent movement process, from [2. Walking spud raised] to [10. Walking spud lowered, movement completed], takes only 5-6 minutes. Figures 1 through 10 in Figure 4 correspond to No. 1 through No. 10 in Figure 7. The amount of hydraulic fluid required for that movement process is shown in the hydraulic fluid usage column in Figure 7.

[0025] The above-mentioned hydraulic fluid usage is first calculated based on the working conditions, the wire winding capacity and hourly hydraulic fluid consumption of each winch 21, the hydraulic fluid consumption of the hydraulic motor 253 of the walking spud 1B, and the hydraulic fluid consumption of the tilting cylinder 29. The working conditions were: 1) 30 minutes per stroke for digging one layer, 2) 6 minutes per ascent, 3) 8 hours of work per day (13 cycles performed, as one cycle takes 36 minutes), and 4) 16 hours of mooring. Furthermore, regarding the specifications and usage time of each generator, 1) during work, the 100kVA work generator 51 was operated for 8 hours, 2) during pressure accumulation, the 100kVA first generator 32 was operated for 6 minutes x 13 times, and 3) when moored, the 75kVA mooring generator 52 was operated for [24 hours - {1) + 2)}] hours. Thus, in this embodiment, during the 30-minute excavation process shown in the upper left of Figure 4 [1. Dredging in progress], by operating one 75KW first electric hydraulic pump 35, more than 2,500L of hydraulic fluid is accumulated in the accumulator 41, thus supplying all of the 2,500L of hydraulic fluid required for the moving process shown in Figure 7.

[0026] Afterward, once the dredging and excavation work, which is the operation performed under the mooring condition of the work vessel by the spud 1 [1. Dredging work in progress], is completed, the next dredging location in the dredging work area is determined, and the vessel is moved one step, as shown in Figure 7. The first generator 32 remains stopped, and the vessel is moved solely by the supply of hydraulic fluid. First, in the process from [2. Raising the walking spud] to [3. Tilting the walking spud] in Figure 4, 500L of hydraulic fluid is sent from the accumulator 41 through the supply pipe 42 to rotate the hydraulic motor 253, raising the walking spud 1B. Then, another 150L of hydraulic fluid is sent through the supply pipe 42 to tilt the walking spud 1B using the tilt cylinder 29 (Figures 2 and 7).

[0027] Next, as shown in [4. Descending the Walking Spud] in the lower right of Figure 4, the walking spud is tilted forward as indicated by the black arrow and driven into the seabed. Then, with the walking spud 1B remaining in place, 900L of hydraulic fluid is supplied from the accumulator 41 through the supply pipe 42 to rotate the hydraulic motors 25 (indicated by symbols 251 and 252), which in turn raise the spud 1 with the winch 21 (Figures 2 and 3). The maximum amount of hydraulic fluid, 900L, is supplied throughout the series of movement processes, raising the two spuds 1 as shown in [5, Fixed Spud Raising] in the upper left of Figure 5. A large amount of mechanical energy is consumed to raise the two spuds 1, but all of this energy is supplied solely by the hydraulic fluid from the accumulator 41.

[0028] Next, 150 L of hydraulic fluid is supplied from the accumulator 41 to the tilting cylinder 29 via the supply pipe 42. The walking spud is moved as if rowing, as shown in [6. Tilting the walking spud and moving the hull] in the lower left of Figure 5, to stop the hull D at a predetermined position. Then, as shown in [7, Fixed Spud Descending] in the upper right of Figure 5, spud 1 is driven into the seabed by its own weight. The position h2 where spud 1 is driven into the seabed is further to the right of the position h1 during the dredging operation in the upper left of Figure 4.

[0029] Subsequently, 500L of hydraulic fluid is supplied from the accumulator 41 to raise the walking spud 1B as shown in [8, Walking spud raised] in the lower right of Figure 5. Then, another 150L of hydraulic fluid is supplied from the accumulator 41 to align the walking spud 1B vertically as shown in [9, Walking spud tilted to vertical position] in the upper left of Figure 6. After that, the walking spud 1B is driven into the seabed by its own weight as shown in [10, Walking spud lowered, movement completed] in the lower left of Figure 6, completing the series of operations.

[0030] As previously described, the operation method for this spud-equipped workboat involves operating the first generator 32 (or first hydraulic engine 31) during the mooring operation of the workboat, i.e., during [1, Dredging Operation] in Figure 4, to accumulate and store hydraulic fluid in the accumulator 41. After the dredging operation is completed, the mechanical energy for the movement process from [2, Walking spud rise] to [10, Walking spud lowering, movement completed] in Figures 4 to 6 is supplied solely by the fluid energy of the hydraulic fluid accumulated and stored in the accumulator 41. The operation method for the spud-equipped workboat is such that the mooring spud 1, which is driven into the seabed, is raised using only the hydraulic fluid from the accumulator 41, and furthermore, all the mechanical energy for the workboat to move from the work site where the spud 1 is driven into the seabed to the next work site using the walking spud 1B is supplied.

[0031] In this manner, the dredger is moored to the dredging site in the dredging area after it has ascended. Even if the first generator 32 is stopped, the operation of the work vessel with the desired spud is completed using only the hydraulic fluid from the accumulator 41 during the upward movement of the hull by the raising of spud 1 and walking spud 1B. Next, the dredging operation shown in the upper left of Figure 4 begins, and the operation of each step described above, from [1. Dredging in progress] to [10. Walking spud descent completed], is repeated sequentially.

[0032] The present invention also allows the first hydraulic pump 33 to be driven directly by the first hydraulic engine 31 instead of the first generator 32 and the first electric hydraulic pump 35, as shown in Figures 8 and 9. In this case, an engine with even lower output can be selected due to improved transmission efficiency. Furthermore, the operating time can be minimized by controlling the start and stop of these components. Instead of Figures 2 and 3, a spud-equipped workboat using this first hydraulic engine 31 and first hydraulic pump 33 can be constructed as shown in Figures 8 and 9, and one method of operating a spud-equipped workboat as described above using Figures 4 to 7 can also be performed.

[0033] Furthermore, the present invention can be incorporated into a main generator 91 that collectively supplies power to the lifelines and control systems of an existing workboat equipped with a spud, power for work while moored, and hydraulic power for three second electric hydraulic pumps 93 931, 932, 933 for raising and lowering the spud and moving the workboat. It is also possible to create a workboat equipped with a spud by incorporating a pressure accumulation system such as the accumulator 41 according to the present invention as an additional device to a conventional workboat, as shown in Figure 10. The existing main generator 91, auxiliary generator 92, second electric hydraulic pump 93, hydraulic motor 25, supply piping 42, starter 77, and hydraulic oil tank 38 are connected as shown in Figure 10 by newly incorporating a small generator 39, accumulator 41, hydraulic piping 34, supply piping 42, control means 71, check valve 73, variable throttle valve 74, and solenoid valve 79. The small generator 59 uses one of the three second electric hydraulic motors 93 in Figure 10. With the generator of the existing equipment (main generator 91) stopped, the hydraulic motor 25 is rotated using only the energy of the hydraulic fluid from the accumulator 41, as in Figures 2 and 3, and the wire 22 is wound up by the winch 21, thereby raising the spud 1 that has been driven into the seabed. The accumulator 41 can raise the mooring spud 1, which is driven into the seabed, solely using the fluid energy of the hydraulic fluid stored in it. Furthermore, it can also supply the mechanical energy needed to move the workboat from one work site to the next within the work area. By incorporating the accumulator 41 and other components of the present invention into existing equipment such as the main generator 91, the aforementioned method of operating a workboat with a spud can also be performed.

[0034] (2) Effects In this configuration of a spud-equipped workboat and its operating method, hydraulic fluid is supplied from the accumulator 41 during the moving process, eliminating the need for a large-capacity 400 kVA main generator 91. During the moving process, it is not necessary to operate the three second electric hydraulic pumps 93 931, 932, and 933 as in the conventional method (Figure 2), thus eliminating the need for a large generator like the main generator 91. As shown in Figure 2, by providing the accumulator 41 and supply piping 42, etc., and supplying power according to the timing and capacity of each power demand, the large-capacity main generator 91 becomes unnecessary, and the capacity of the first generator 32, which replaces the large main generator 91, can be changed to a smaller generator with about 1 / 4 of the capacity. Furthermore, if the energy from the hydraulic fluid of the accumulator 41 is used to provide the mechanical energy for the spud 1, which is driven into the seabed B, then the maximum amount of hydraulic fluid, which is 900L, can be saved during the moving process, thus eliminating the need for the main generator of the large-capacity generator.

[0035] Furthermore, with this invention, instead of continuously operating the main generator 91 as in the conventional method, the operating time of the first generator 32 can be minimized by start-stop control. By controlling the start-stop of the first generator 32, which is significantly smaller than the main generator 91, the generator can be stopped for about 30 minutes during one cycle, thus achieving a significant energy-saving effect compared to the conventional method. As shown in Figure 7, 2,500 liters of hydraulic fluid are required. Once this 2,500 liters of hydraulic fluid has been pressurized in the accumulator 41, there is no need to operate the first electric hydraulic pump 35 or the first hydraulic pump 33 until the next moving process. As shown in Figure 7, the time required to pressurize the hydraulic fluid in the accumulator 41 is completed within the dredging time, so the first generator 32, which supplies power for the hydraulics, can be stopped. This allows for fuel savings and a corresponding reduction in CO2 emissions.

[0036] In addition, conventionally, the above 27m 3Not only in this class of dredger, but also in other dredgers, the main generator 91 continues to operate during dredging operations in preparation for the next movement phase. This resulted in a large surplus of power, as well as problems such as increased fuel consumption, wasted CO2 emissions, carbon buildup due to low-load operation of the diesel engine, and unnecessary wear and tear on equipment. This system solves all of these problems at once.

[0037] Furthermore, since hydraulic fluid is supplied from the accumulator 41 during the moving process, not only is the main generator 91, which is a large-capacity generator, unnecessary, but it also becomes unnecessary to operate the three second electric hydraulic pumps 93 931, 932, and 933 as in the conventional system shown in Figure 10. Furthermore, by replacing the main generator 91 with a smaller first generator 32, this invention also exempts the system from the IMO Stage 2 exhaust gas regulations required for all prime movers of 130 kW or more in construction projects commissioned by the Ministry of Land, Infrastructure, Transport and Tourism.

[0038] Furthermore, if the first hydraulic pump 33 is driven directly by the first hydraulic engine 31, as shown in Figures 8, 9, and the lower left of Figure 1, the transmission efficiency will be improved, making it possible to select an engine with even lower output for the first hydraulic engine 31. Furthermore, as shown in Figure 10, the system can be applied to existing workboats equipped with spuds, such as dredgers, and the accumulator 41 and small generator 39 of the present invention can be incorporated. When incorporated, it is possible to switch between the conventional system and the components of the present invention that include the accumulator 41, which not only helps in energy saving measures but also improves the reliability of the equipment by providing backup for both hydraulic power sources. Thus, the spud-equipped workboat and its operating method of the present invention exhibit the numerous excellent effects described above and are extremely beneficial.

[0039] Furthermore, the present invention is not limited to the embodiments shown above, and various modifications can be made within the scope of the present invention depending on the purpose and application. The shape, size, number, etc. of the spud 1, first hydraulic engine 31, first generator 32, first hydraulic pump 33, hydraulic piping 34, first electric hydraulic pump 35, small generator 39, accumulator 41, supply piping 42, etc. can be appropriately selected according to the application. In this embodiment, the work vessel with a spud is used as a dredger, but of course, it can also be a crane vessel or the like with a spud 1 attached. [Explanation of Symbols]

[0040] 1. Spud (fixed spud) 21 Winch 25 Hydraulic motor 31 First Hydraulic Engine 32 First Generator 33 First Hydraulic Pump 35 First Electric Hydraulic Pump 41 Accumulator 91 Main generator

Claims

1. In a workboat equipped with a spud for mooring other workboats, A columnar spud is thrust from the hull into the seabed, Installed on the hull, the first hydraulic engine or first generator is used for raising and lowering the spud and for moving the workboat, An accumulator that stores and stores hydraulic fluid by converting the output energy of the first hydraulic engine into fluid energy using a first hydraulic pump, or the output energy of the first generator into fluid energy using a first electric hydraulic pump, The system comprises a supply pipe that supplies hydraulic fluid from the accumulator to the hydraulic motor of the winch that raises and lowers the spud, A workboat equipped with a spud, characterized in that the energy of the hydraulic fluid from the accumulator alone is used to rotate the hydraulic motor, which in turn winds up the wire with the winch, causing the spud, which is driven into the seabed, to rise.

2. The spud-equipped workboat according to claim 1, wherein the output energy of the first hydraulic engine is supplied by the first hydraulic pump, or the output energy of the first generator is supplied by the first electric hydraulic pump, or the output energy of the first hydraulic engine is supplied by the first hydraulic pump.

3. A workboat with a spud according to claim 1 or 2, further comprising a main generator that collectively supplies power for lifelines and control systems, power for work while moored, and power for hydraulics related to a second hydraulic pump for raising and lowering the spud and for moving the workboat.

4. In the operation method of a workboat equipped with a spud for mooring other workboats, A columnar spud is thrust from the hull into the seabed, Installed on the hull, the first hydraulic engine or first generator is used for raising and lowering the spud and for moving the workboat, An accumulator that stores and stores hydraulic fluid by converting the output energy of the first hydraulic engine into fluid energy using a first hydraulic pump, or the output energy of the first generator into fluid energy using a first electric hydraulic pump, The system comprises a supply pipe that supplies hydraulic fluid from the accumulator to the hydraulic motor of the winch that raises and lowers the spud, During the mooring operation of the work vessel, the first hydraulic engine or the first generator is operated to store hydraulic fluid in the accumulator under pressure. A method for operating a work vessel equipped with a spud, characterized in that, after the work vessel is moored, the spud for mooring, which is driven into the seabed, is raised solely by the fluid energy of the hydraulic fluid stored in the accumulator, and further, mechanical energy is supplied in the work area to move the work vessel from the work site where the spud is driven into the sea to the next work site.

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