AU2011255697B2

AU2011255697B2 - Dumping system

Info

Publication number: AU2011255697B2
Application number: AU2011255697A
Authority: AU
Inventors: Gerrit Jan Grundlehner
Original assignee: Baggermaatschappij Boskalis BV
Current assignee: Baggermaatschappij Boskalis BV
Priority date: 2010-05-17
Filing date: 2011-05-17
Publication date: 2015-02-05
Anticipated expiration: 2031-05-17
Also published as: MX2012013335A; AU2011255697A1; BR112012029265B1; WO2011145935A3; BR112012029265A2; NL2004731C2; CA2799709A1; WO2011145935A2

Abstract

Dumping system for dumping bulk materials on the sea bottom for supporting a subsea infrastructure or on a subsea infrastructure on the sea bottom, comprising a dumping vessel with a floating hull provided with a hoisting device, and a first bulk material shuttle which is suspended from the hoisting device to be lowered towards the sea bottom, wherein the first bulk material shuttle is provided with a first bulk material container for carrying inserted bulk, wherein the dumping vessel further comprises a dosing device for release of the bulk material from the first bulk material container.

Description

1 PCTP189257A Dumping system BACKGROUND The invention relates to a dumping system for dumping bulk materials, such as stones, rocks, sand or 5 concrete blocks on the sea bottom for supporting a subsea infrastructure or on a subsea infrastructure on the sea bottom, such as a pipeline. A known dumping vessel comprises a hull with a hole in the middle through which pipe segments are lowered 10 into the water. The pipe segments are attached to each other to form a continuous fall pipe. The vessel has been provided with two bulk material storage chambers placed within the hull, two belt conveyors next to the storage chambers and two excavators in between the storage chambers 15 and the belt conveyors. Bulk material is excavated from the bulk material storage chambers and placed on the belt conveyors. Once the bulk material reaches the end of the belt conveyors, they are dropped down the fall pipe through the hole in the middle of the hull. At the end of the fall 20 pipe, the bulk material is dropped onto the sea bottom. The maximum depth that can be reached is limited by the dynamic forces of the sea conditions affecting the fall pipe and the weight of the fall pipe it self. The 6036838_1 (GHMatters) P91781.AU DENISET 2 depth reachable with the known dumping vessel is approximately one-thousand meters. The sea conditions acting on the hull need to be within certain operational limits during a sufficient time window, as the buildup of 5 the known dumping vessel takes approximately one hour per two-hundred-and- fifty meters of fall-pipe length. For lengths over one-thousand meters, the required buildup time becomes disproportional to the time window of two or three hours in which the rocks are actually dropped. 10 It is desirable for the present invention to provide a dumping system that can accurately drop bulk materials at large depth. It is desirable for the present invention to provide a dumping vessel that has a short preparation time 15 prior to actually dropping bulk materials on a sea bottom. SUMMARY OF THE INVENTION 20 According to a first aspect, the present invention provides a dumping system for dumping bulk materials on the sea bottom for supporting a subsea infrastructure or on a subsea infrastructure on the sea bottom, comprising a dumping vessel with a floating hull 25 provided with a hoisting device, and a first bulk material shuttle which is suspended from the hoisting device to be lowered towards the sea bottom, wherein the first bulk material shuttle is provided with a first bulk material container for carrying inserted bulk, wherein the dumping 30 vessel further comprises a dosing device for release of the bulk material from the first bulk material container. The first bulk material shuttle can enable the dumping system to carry a load of bulk material inserted in the first bulk material container while descending towards the sea bottom 35 to subsequently dump the bulk material onto the sea bottom and/or onto a subsea infrastructure on the sea bottom. 6036838_1 (GHMatters) P91781.AU DENISET 3 On the one hand, the first bulk material shuttle which is suspended from the hoisting device can be positioned much more close to the dumping site, since the depth position is substantially continuously adjustable and 5 the hoisting device can be provided with an active heave control in order to at least partially compensate for vertical movements of the vessel due to the heaving sea. By positioning the first bulk material shuttle closer to the dumping site, the dumping system can more accurately dump 10 the bulk material. On the other hand, the first bulk material shuttle can be lowered as soon as it has been filled, which takes much less time than the build-up of the fall-pipe of the conventional system. 15 In an embodiment the first bulk material shuttle is suspended from the hoisting device by one or more hoisting cables. This way, large depths can be reached by the first bulk material shuttle, only depending on the length of the cables, moreover, in a fast manner. 20 In an embodiment the hoisting cables have an effective length of at least one-thousand meters, preferably at least one-thousand-five-hundred meters, most preferably at least two-thousand meters. The effective length of the hoisting cables, referring to the length 25 between the hoisting device and the top end of the first bulk material shuttle, determines the approximate depth that the first bulk material shuttle can reach when the hoisting cables have been fully paid out. An advantage of such long cables is that due to the amount of elastic 30 stretch of these cables, the elastic stretch can at least partially compensate for vertical movements of the vessel due to the heaving sea, providing a passive heave compensation. In an embodiment in which the hoisting cables for 35 the first bulk material shuttle are fully paid out with the first bulk material shuttle suspended thereof, the first 6036838_1 (GHMatters) P91781.AU DENISET 4 bulk material shuttle is at a depth of at least one thousand meters below sea level, preferably at a depth of at least one-thousand-five-hundred meters below sea level, most preferably at a depth of at least two-thousand meters 5 below sea level. Thus the dumping vessel can drop rocks from the first bulk material shuttle at large depth. In an embodiment the sea bottom facing end of the first bulk material container is provided with an opening, wherein the dosing device is placed in front of the opening 10 in order to control the flow of bulk material from within the first bulk material container through the opening. The dosing device enables the dumping system to distribute bulk material in a controlled manner, for example when distributing bulk material along a path or on several 15 locations. In an embodiment the system is provided with an umbilical cable having multiple conductors that connect the first bulk material shuttle to a control unit on the hull. This way, signals, electric power and hydraulic power can 20 be sent through the umbilical cable to power and control the first bulk material shuttle. In an embodiment the dosing device is electrically and/or hydraulically powered, wherein the dosing device is connected via the umbilical cable to the 25 control unit on the hull. Therefore, the dosing device can be remotely operated from the control unit. In an embodiment the first bulk material shuttle is provided with at least one position detection device. The position detection unit can detect the position 30 relative to the hull and/or the sea bottom and/or an object on the sea bottom. In an embodiment the position detection device is connected via the umbilical cable to the control unit. Therefore, signals from the position detection device can 35 be remotely interpreted via the control unit. In an embodiment the position detection device is 6036838_1 (GHMatters) P91781.AU DENISET 5 a sonar. By sending acoustic signals and by receiving reflected acoustic signals, the position relative to the hull and/or the sea bottom and/or an object on the sea bottom can be accurately determined. 5 In an embodiment the first bulk material shuttle is provided with at least one positioning device. The positioning device can accurately position the first bulk material shuttle at large depth in relation to the position of the hull and/or the sea bottom and/or an object on the 10 sea bottom. The positioning device can compensate for external forces such as waves acting on the dumping vessel, in particular the hull of the dumping vessel or water current acting on the hoisting cables and the first bulk material shuttle. 15 In an embodiment the positioning device is connected via the umbilical cable to the control unit. Therefore, the positioning device can be remotely operated from the control unit. In an embodiment the positioning device comprises 20 a sideway thruster, arranged to provide a thrust force that can move the first bulk material shuttle in a horizontal plane. The sideways thrusters can produce sideways thrust in two directions in order to position the first bulk material shuttle. 25 In an embodiment the first bulk material shuttle is provided with multiple positioning devices, arranged to provide a combined thrust force that can move the first bulk material shuttle in any sideways direction in a horizontal plane. The positioning devices can accurately 30 position the first bulk material shuttle. In an embodiment the hull is provided with a bulk material storage and a transport assembly extending from the bulk material storage to the first bulk material shuttle. The transport assembly can extract and transport 35 bulk material from the bulk material storage to the first bulk material shuttle. 6036838_1 (GHMatters) P91781.AU DENISET 6 In an embodiment the first bulk material shuttle is provided with an open top end, wherein the transport assembly extends outside the hull to directly drop bulk material into the open top end of the first bulk material 5 shuttle into the first bulk material container of the first bulk material shuttle. This way, the first bulk material container can be filled with bulk material before descending to the sea bottom. In an embodiment the dumping system comprises a 10 second bulk material shuttle, which is suspended from the hoisting device to be lowered towards the sea bottom, wherein the hoisting device is arranged for descending and ascending the first bulk material shuttle and the second bulk material shuttle in mutually opposite directions. This 15 enables that one of the bulk material shuttles can release its bulk material while the other is filled with bulk material. In an embodiment the first bulk material shuttle and the second bulk material shuttle are interconnected via 20 the hoisting device so that when the first bulk material shuttle descends, the second bulk material shuttle ascends, and vice versa, preferably in a synchronized manner. The two bulk material shuttles can compensate their weight to some extent. 25 In an embodiment the dumping system comprises a remotely operated submergible vehicle, wherein the vessel is provided with an umbilical cable having multiple conductors that connect the remotely operated vehicle to a control unit on the hull, wherein remotely operated vehicle 30 is provided with a positioning device and a position detection device, wherein the remotely operated vehicle comprises a connector for connecting the remotely operated vehicle to the first bulk material shuttle. This configuration can enable site survey of the sea bottom 35 during ascent and descent of the bulk material shuttles. Moreover, the bulk material shuttles can be kept free from 6036838_1 (GHMatters) P91781.AU DENISET 7 complex devices such as thrusters and position detection devices. In an embodiment the remotely operated vehicle is provided with an interface that interfaces with the dosing 5 device of the first bulk material shuttle while the remotely operated vehicle is connected to the first bulk material shuttle, for operating the dosing device. In this way, the dosing devices of the bulk material shuttles can be kept free from complex controls. 10 According to a second aspect, the present invention provides a method for dumping bulk materials on the sea bottom for supporting a subsea infrastructure or on a subsea infrastructure on the sea bottom with a dumping system comprising a dumping vessel with a floating hull 15 provided with a hoisting device, and a first bulk material shuttle which is suspended from the hoisting device to be lowered towards the sea bottom, wherein the first bulk material shuttle is provided with a first bulk material container for carrying inserted bulk, wherein the dumping 20 vessel further comprises a dosing device for release of bulk material from the first bulk material container, wherein the method comprises the following steps; filling the first bulk material container with bulk material, submerging the first bulk material shuttle, having the 25 first bulk material shuttle descent suspended from the hoisting device towards the sea bottom, having the dosing device release the bulk material from the first bulk material container, letting the bulk material drop from the first bulk material shuttle on to the sea bottom. The first 30 bulk material shuttle can enable the dumping system to carry a load of bulk material inserted in the first bulk material container while descending towards the sea bottom to subsequently drop the bulk material onto the sea bottom. In an embodiment the bulk material shuttle 35 comprises at least one positioning device, wherein the first bulk material shuttle comprises at least one 6036838_1 (GHMatters) P91781.AU DENISET 8 positioning device, wherein dumping system comprises a control unit, wherein the method comprises the step of controlling the positioning device with the control unit to position the first bulk material shuttle relative to the 5 hull and/or relative to the sea bottom and/or relative to an object on the sea bottom. The positioning device can accurately position the first bulk material shuttle at large depth and compensate for external forces such as waves acting on the hull or water flow acting on the 10 hoisting cables and the first bulk material shuttle. In an embodiment the first bulk material shuttle comprises at least one position detection device, wherein the method comprises the step of detecting the position relative to the hull and/or the sea bottom and/or an object 15 on the sea bottom with the position detection device. The information about the position of the hull, the sea bottom and/or an object on the sea bottom can be used to determine the position of the first bulk material shuttle relative to the hull, the sea bottom and/or an object on the sea 20 bottom. In an embodiment the dumping vessel comprises a bulk material storage inside the hull and a transport device, wherein the first bulk material shuttle is provided with an open top end, wherein the method comprises the 25 following steps; submerging the first bulk material shuttle suspended from the hoisting device until the open top end of the first bulk material shuttle is below and in proximity of the water line, transporting bulk material with the transport device from the bulk material storage to 30 the first bulk material container, and dropping bulk material trough the open top end of the first bulk material shuttle into the first bulk material container. This way, the first bulk material container can be filled with bulk material before descending to the sea bottom in a fast 35 manner. In an embodiment the dumping system comprises a 6036838_1 (GHMatters) P91781.AU DENISET 9 second bulk material shuttle, which is suspended from the hoisting device to be lowered substantially parallel to the first bulk material shuttle towards the sea bottom, wherein the method further comprises the following steps; having 5 the hoisting device descend the first bulk material shuttle while the second bulk material shuttle ascends and vice versa. This enables that one of the bulk material shuttles can release its bulk material while the other is filled with bulk material. Furthermore, the two bulk material 10 shuttles can compensate their weight to some extent. In an embodiment the dumping system comprises a remotely operated submergible vehicle, wherein the vessel is provided with an umbilical cable having multiple conductors that connect the remotely operated vehicle to a 15 control unit on the hull, wherein remotely operated vehicle is provided with a positioning device and a position detection device, wherein the remotely operated vehicle comprises a connector for connecting the remotely operated vehicle to the first bulk material shuttle, wherein the 20 method further comprises the following steps; connecting the connector of the remotely operated vehicle to the first bulk material shuttle in its descended position, positioning the first bulk material shuttle above a target on the sea bottom, releasing the bulk material from the 25 first bulk material shuttle, terminating the connection between the remotely operated vehicle and the first bulk material shuttle, connecting the connector of the remotely operated vehicle to the second bulk material shuttle in its descended position, positioning the second bulk material 30 shuttle above a target on the sea bottom, releasing the bulk material from the second bulk material shuttle and terminating the connection between the remotely operated vehicle and the second bulk material shuttle. This configuration can enable site survey of the sea bottom 35 during ascent and descent of the bulk material shuttles. Moreover, the bulk material shuttles can be kept free from 6036838_1 (GHMatters) P91781.AU DENISET 10 complex devices such as thrusters, position detection devices and dosing device controls. The various aspects and features described and shown in the specification can be applied, individually, 5 wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications. 10 BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be elucidated on the basis of an exemplary embodiment shown in the 15 attached schematic non-limiting drawings, in which: figure 1 shows a side view of a first embodiment of a dumping vessel with a bulk material shuttle according to the invention; figure 2 shows a rear view of the vessel with the 20 bulk material shuttle according to figure 1; figure 3 shows a bottom view of the bulk material shuttle according to figure 1; figure 4 shows a detail of figure 1; figure 5 shows a side view of the vessel with the 25 hopper according to figure 4, with the bulk material shuttle placed underneath the water line; figures 6 and 7 shows a side view of the vessel with the hopper according to figure 4, with the bulk material shuttle positioned above the sea bottom; 30 figure 8 shows a side view of the vessel according to figure 4, with an alternative bulk material shuttle; figure 9 shows a rear view of a second embodiment of a dumping vessel with bulk material shuttles according 35 to the invention; figure 10 shows a rear view of a third embodiment 6036838_1 (GHMatters) P91781.AU DENISET 11 of a dumping vessel with bulk material shuttles according to the invention. 5 DETAILED DESCRIPTION OF THE INVENTION Figures 1 and 2 show a first embodiment of the invention. These figures show a dumping vessel 1 with a bulk material chute or a bulk material shuttle 6 for 10 dumping bulk materials 8, such as rocks, stones, sand or concrete blocks, out of the bulk material shuttle 6 on a subsea infrastructure on the sea bottom 9, such as a pipeline 7. The dumped bulk material 8 is for example used to protect subsea pipelines 7 from deployed anchors, or to 15 create flyovers when dealing with crossing subsea pipelines 7, or to press pipelines 7 against the sea bottom 9 to prevent thermal expansion. The vessel 1 comprises a floating hull 2. The hull 2 has an elongated shape and comprises a bow 21, a 20 stern 22, a port side 23, a starboard side 24 and a deck 3. The vessel 1 is provided with a bridge 10, from where different functionalities of the vessel 1 are controlled. The vessel 1 is provided with a first bulk material storage chamber 11 and a second bulk material storage chamber 12 25 inside the hull 2. The vessel 1 comprises a first crane or excavator 13 placed next to the first bulk material storage chamber 11 and a second crane or excavator 14 placed next to the second bulk material storage chamber 12. The vessel 1 comprises a belt conveyor 15 that runs along the two 30 excavators 13, 14 up to the stern 22 of the vessel 1. In proximity of the stern 22, the vessel 1 is provided with a first winch 31 that hauls in or pays out a first hoisting wire 35, a second winch 32 that hauls in or pays out a second hoisting wire 36, a third winch 33 that 35 hauls in or pays out a third hoisting wire 37, and a fourth winch 34 that hauls in or pays out an umbilical cable 38. 6036838_1 (GHMatters) P91781.AU DENISET 12 The umbilical cable 38 is provided with an insulation layer and multiple wires that run along the inside of the insulation layer and which have conductivity characteristics suitable for transporting light signals, 5 information signals and/or electrical power from the vessel 1 to the bulk material shuttle 6. At the stern 22, the vessel 1 is provided with a hoisting frame 4, comprising a first upright 41 and a second upright 42, which are connected with respectively a 10 first hinge 43 and a second hinge 44 to respectively the portside 23 and the starboard side 24 of the deck 3. The hoisting frame 4 comprises a horizontal beam 45 extending between the ends of the two uprights 41 opposite to the ends attached to the hinges 43, 44. The first hoisting wire 15 35 from the first winch 31 is attached to the horizontal beam 45 for lowering or hoisting the hoisting frame 4 which pivots around the hinges 43, 44. Alternatively, the lowering and hoisting can be arranged by placing hydraulic cylinders between the hoisting frame 4 and the deck 3. The 20 hoisting frame 4 comprises a first pulley 46, a second pulley 47, a third pulley 48 and a fourth pulley 49 which form a first set of pulleys 46-49 attached to the horizontal beam 45. The second and third hoisting wires 36, 37 from respectively the second and third winch 32, 33 run 25 towards the hoisting frame 4, over the first set of pulleys 46-49, and then downwards to the bulk material shuttle 6. Together, the second and third hoisting wires 36, 37 carry the weight of the bulk material shuttle 6. The second and third hoisting wires 36, 37 can also be one and the same 30 wire. This single hoisting wire is attached with one end to the second winch 32, runs over the first set of pulleys 46 49, down to the bulk material shuttle 6, and up again to the set of pulleys 46-49. The other end of the single hoisting wire is attached to the third winch 33. Said 35 single hoisting wire can prevent uneven hoisting velocities. The hoisting frame 4 comprises a fifth pulley 6036838_1 (GHMatters) P91781.AU DENISET 13 50 attached to the horizontal beam 45. The umbilical cable 38 from the fourth winch 34 runs towards the hoisting frame 4, over the fifth pulley 50 and downwards to the bulk material shuttle 6. 5 In an embodiment, the second and/or third winch 32, 33 are provided with an active heave control. The second and/or third winch are activated substantially contrarily to the vertical motion of the vessel due to a heaving sea. 10 The bulk material shuttle 6 comprises four vertical steel walls 60 that form a hollow, box shaped bulk material container 61. The bulk material container 61 is provided with an open top end 62 and an open bottom end 63. The enclosed volume of the bulk material container 61 is 15 dimensioned specifically for the intention of dropping the bulk material 8 at great depth on the sea bottom 9. The volume of the bulk material container 61 is approximately two-hundred-and-fifty cubic meters. The top end 62 of the bulk material shuttle 6 is provided with a sixth pulley 64 20 and seventh pulley 70, which connect to respectively the second and third hoisting wires 36, 37. At the bottom end 63 of the bulk material shuttle 6, the walls 60 of the bulk material container 61 are tapered to form a narrow opening 65. The bulk material shuttle 6 is provided with a 25 dispensing or dosing device 66, which, in this embodiment, is of the clamshell bucket type. The dosing device 66 is placed in front of the opening 65 and comprises a first bucket halve 67 and a second bucket halve 68, which, in the closed position as depicted in figure 1, shut or close the 30 opening 65 in order to prevent bulk material 8 from falling from out of the bulk material container 61. Alternatively, the dosing device 66 comprises sliding doors. Figures 3 and 6 shows that at the bottom end 63, the bulk material shuttle 6 is provided with four thrusters 35 69; one at each corner formed by two of the walls 60. The thrusters 69 are capable of delivering a thrust force in a 6036838_1 (GHMatters) P91781.AU DENISET 14 first direction A and a second direction B. The bulk material shuttle 6 comprises a first position detection device 71 at the bottom end 63 for detecting objects underneath the bulk material shuttle 6, and a second 5 position detection device 72 at the top end 62 for detecting the position of the hull 2 and subsequently determining the position of the position of the bulk material shuttle 6 relative to the detected position of the hull 2. Both position detection devices 71, 72 operate like 10 a sonar by sending an acoustic signal and receiving reflected signals deflected by objects 7, the sea bottom 9 or the hull 2. Figure 6 shows that the maximum depth D reachable with the bulk material shuttle 6 is determined by the 15 length of the second and third hoisting wires 36, 37 and the umbilical cable 38. The second and third hoisting wires 36, 37 can either have there ends connected to the bulk material shuttle 6, or have a length that enables one or more loops from the hoisting frame 4, downwards to the bulk 20 material shuttle 6, through the sixth pulley 64 and back up to the hoisting frame 4. In the first case, the length of the wires 36, 37 substantially corresponds to the maximum depth D that can be reached by the bulk material shuttle 6. However, preferably, the second and third hoisting wires 25 36, 37 are attached to the bulk material shuttle 6 in a loop, in order to distribute the weight of the bulk material shuttle 6 and its bulk material 8 over several wire 36, 37 segments. In the case of one or more loops, the length of the wires 36, 37 substantially corresponds to a 30 factor two or more of the maximum reachable depth D. The effective cable length thus obtained refers to the length of the cable segment between the fifth pulley 50 on the hoisting frame 4 and the sixth pulley 64 on the bulk material shuttle 6, which substantially corresponds to the 35 depth D of the bulk material shuttle 6 that can be reached with these wires 36, 37. The second and third hoisting 6036838_1 (GHMatters) P91781.AU DENISET 15 wires 36, 37 and the umbilical cable 38 have an effective length that enables the bulk material shuttle 6 to reach a depth D of more than one-thousand meters, preferably more than one-thousand-five-hundred meters, preferably more than 5 two-thousand meters, while being connected to these cables 36-38. Figures 4-7 show subsequent steps of the operation of the dumping vessel 1. Figure 4 shows the bulk material shuttle 6 on the 10 deck 3 of the vessel 1 prior to its deployment. The first winch 31 has hauled in the first hoisting wire 35 and as result, the hoisting frame 4 in its substantially upright position above the deck 3. The second and third hoisting wires 36, 37 and the umbilical cable 38 are hauled in onto 15 their respective winches 32, 33, 34. The bulk material storage chambers 11, 12 are filled with bulk material 8. The vessel 1 is stationary positioned based on global positioning signals received by a global positioning system on the vessel 1. 20 Figure 5 shows the situation wherein the bulk material shuttle 6 is submerged with its top end 62 just below the water line W. In order to get to this situation the bulk material shuttle 6 has been lifted off the deck 3 by pulling in the second and third hoisting wires 36, 37. 25 The first hoisting wire 35 has been paid out by the first winch 31 and as a result, the hoisting frame 4 is in its downwardly pivoted position. In this position, the hoisting frame 4 extends outside of the stern 22 with its horizontal beam 45 above the water. Subsequently the second and third 30 hoisting wires 36, 37 and the umbilical cable 38 have been paid out by their respective winches 32, 33, 34, in order to lower the bulk material shuttle 6, which is suspended on the second and third hoisting wires 36, 37, into the water. With the bulk material shuttle 6 in the position 35 as shown in figure 5, the excavators 13, 14 are operated to extract and transport bulk material 8 from the bulk 6036838_1 (GHMatters) P91781.AU DENISET 16 material storage chambers 11, 12 onto the belt conveyor 15. Figure 5 shows that the belt conveyor 15 is transporting a load of bulk material 8 towards the stern 22, wherein a portion has fallen down into the bulk material container 61 5 of the bulk material shuttle 6 via path C. Figure 6 shows the situation following the situation shown in figure 5, wherein the bulk material shuttle 6 is positioned at a depth D of approximately two thousand meters, approximately five meters above the sea 10 bottom 9. In order to get to this position, the second and third hoisting wires 36, 37 and the umbilical cable 38 have been paid out by their respective winches 32, 33, 34. During the descent, the thrusters 69 and the position detection devices 71, 72 receive electrical power from the 15 bridge 10 via the umbilical cable 38. The first position detection device 71 has send out acoustic signals which are reflected against the hull 2. The second position detection device 72 has send out acoustic signals which are reflected on the sea bottom 9 or objects such as a pipeline 7 on the 20 sea bottom 9. The umbilical cable 38 transports information about these reflected signals from the position detection devices 71, 72 to the bridge 10 on the deck 2. The signals from the position detection devices 71, 72 are displayed onto a readout station. Based on this readout station, a 25 human operator or a computerized positioning system can control the thrusters 69 with signals send from the bridge 10, via the umbilical cable 38 to the thrusters 69. The thrusters 69 produce thrust forces that generate an effective positioning force F that accurately positions 30 either the bulk material shuttle 6 in relation to the vessel 1, or the opening 65 of the bulk material shuttle 6 in relation to a desired location L or an object such as a pipeline 7 on the sea bottom 9. The position can be accurately determined, because the position of the vessel 1 35 is known from the global positioning system and the position of the bulk material shuttle 6 in relation to the 6036838_1 (GHMatters) P91781.AU DENISET 17 vessel 1 is known from the signals of the first position detection device 71. Figure 7 shows the situation following the situation as shown in figure 5, wherein the dosing device 5 66 has received electric or hydraulic power and control signals from the bridge 10 via the umbilical cable 38. As a result, the two bucket halves 67, 68 have moved apart, releasing bulk material 8 in a controlled flow from the bulk material container 61 through the opening 65 of the 10 bulk material container 61. During the release of bulk material 8, the thrusters 69 can be controlled to position the bulk material shuttle 6 to drop bulk material 8 along a specific path or at a specific location L. The release of bulk material 8 can also be interrupted and later on 15 continued by closing and opening the two bucket halves 67, 68. The signals of the second position detection device 72 can also be used to analyze the result of the rock dropping. Figure 8 shows an alternative embodiment of the 20 dosing device 166, comprising a cylindrical drum 167 with a number of scoops 168 extending outward. The scoops 168 have a height resulting in a volume enclosed between two consecutive scoops 168 that can accommodate bulk material 8 that falls through the opening 65. The enclosed bulk 25 material 8 is released as the cylindrical drum 167 rotates in direction R. Once the bulk material shuttle 6 has released all its bulk material 8, it can be hoisted up by the second and third hoisting wires 36, 37 to ascent to a position as 30 shown in figure 5. This involves pulling in the second and third hoisting wires 36, 37 and the umbilical cable 38 with their respective winches 32, 33, 34. Subsequently, the bulk material container 61 can be reloaded as described in the text about figure 5. Alternatively it can be taken out of 35 the water to be placed on the deck 3 of the vessel 1, involving the steps described above in a reverse order. 6036838_1 (GHMatters) P91781.AU DENISET 18 Placing the bulk material shuttle 6 from the deck 3 of the vessel 1 into water or taking it out of the water onto the deck 3 of the vessel takes approximately ten minutes. With a depth D of two-thousand meters, a complete 5 descent of the bulk material shuttle 6 takes twenty minutes, a complete release of bulk material 8 from the bulk material shuttle 6 takes ten minutes, a complete ascent of the bulk material shuttle 6 takes twenty minutes and a complete reload takes ten minutes. The complete cycle 10 as described above thus takes approximately sixty minutes. A buildup and a single cycle therefore totals a time window of as little as seventy minutes, which enables the bulk material shuttle 6 to be used in small windows of opportunity, for example when the weather conditions are 15 unstable. In an alternative embodiment, the vessel 1 is provided with an opening in the bottom of the hull 11. The hoisting frame 4 or another hoisting device is positioned above the opening, with the bulk material shuttle 6 20 suspended thereof. The bulk material shuttle 6 is subsequently lowered into and hoisted out of the water through the opening in the hull 11. After submerging the bulk material shuttle 6, the cycle of descending, dropping, ascending and reloading is similar to the cycle described 25 above. Figure 9 shows rear view of a second embodiment of a dumping vessel 101 with bulk material shuttles 106 according to the invention. The second embodiment comprises many features that correspond with the first embodiment 30 which are therefore provided with the same reference numbers. In proximity of the stern 22, the vessel 101 is provided with said first winch 31 for the hoisting wire 35 of the hoisting frame 4, said second winch 32 and said 35 third winch 33 that in this embodiment hauls in or pays out the ends of the common second hoisting wire 36, and two of 6036838_1 (GHMatters) P91781.AU DENISET 19 said fourth winches 34 that each hauls in or pays out an umbilical cable 38 as described before. The hoisting frame 4 comprises said first pulley 46, second pulley 47, third pulley 48 and fourth pulley 49, 5 and between the second pulley 47 and third pulley 48 a wire traction unit 80 comprising two synchronized driven traction pulleys 81. The two identically configured bulk material shuttles 106 each comprise said sixth pulley 64 and seventh pulley 70, which in this embodiment are 10 positioned in the vertical plane of symmetry of the shuttle 106. The second hoisting wire 36 runs from the second winch 32 subsequently through the first pulley 46, through the seventh pulley 47 and the sixth pulley 64 of the left bulk material shuttle 106, through the second pulley 47, through 15 the traction pulleys 81, through the third pulley 48, through the seventh pulley 47 and the sixth pulley 64 of the right bulk material shuttle 106, through the fourth pulley 49 and to the third winch 33. This configuration of the second hoisting wire 36 20 enables the two bulk material shuttles 106 to be submerged into the water by paying out both the second winch 32 and third winch 33, wherein the traction unit 80 subsequently enables the two bulk material shuttles 106 to descent or ascent in opposite directions simultaneously by moving the 25 second hoisting wire 36 in one of the opposite traction directions G of the traction unit 80. The length of the second hoisting wire 36 enables that one of the bulk material shuttles 106 can release its bulk material as described and shown at figure 7 while the other is filled 30 with bulk material as described and shown at figure 5. The two bulk material shuttles 106 compensate their weight to some extent. The traction unit 80 can be configured to move the second hoisting wire 36 at multiple higher speeds than the second winch 32 and third winch 33 which are mainly 35 configured to store the long second hoisting wire 36. Figure 10 shows rear view of a third embodiment 6036838_1 (GHMatters) P91781.AU DENISET 20 of a dumping vessel 201 with bulk material shuttles 206 according to the invention. The second embodiment comprises many features that correspond with the second embodiment which are therefore provided with the same reference 5 numbers. The bulk material shuttles 206 are not necessarily provided with the first position detection devices 71 at the bottom end 63 for detecting objects underneath the bulk material shuttle 206, and the second 10 position detection devices 72 at the top end 62 for detecting the position of the hull 2. Moreover, the four thrusters 69 are optional. In this embodiment, the dumping vessel 201 is provided with a remotely operated vehicle (ROV) 301 that is connected to the bridge 10 via the 15 umbilical cable 38. The remotely operated vehicle (ROV) comprises position detection devices, camera's and multiple thrusters 261 to position the vehicle 301 at any position under water in a controlled manner, and a connector 302 to connect the vehicle 301 to one of the lowered bulk material 20 shuttles 206. When connected to one of the bulk material shuttles 206, the vehicle 301 can position said one bulk material shuttle 206 above a target area. The connector 302 and the bulk material shuttles 206 are both provided with an interface 303, 210 to power the movement of the bucket 25 halves 67, 68 via the remotely operated vehicle 301, in order to control the release of bulk material from the bulk material shuttles 206. This configuration enables site survey of the sea bottom 9 during ascent and descent of the bulk material shuttles 206. Moreover, the bulk material 30 shuttles 206 can be kept free from complex devices such as thrusters and position detection devices. It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the 35 invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be 6036838_1 (GHMatters) P91781.AU DENISET 21 encompassed by the scope of the present invention. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part 5 of the common general knowledge in the art, in Australia or any other country. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary 10 implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 15 6036838_1 (GHMatters) P91781.AU DENISET

Claims

1. Dumping system for dumping bulk materials on the sea bottom for supporting a subsea infrastructure or on a subsea infrastructure on the sea bottom, comprising a dumping vessel with a floating hull provided with a 5 hoisting device, and a first bulk material shuttle which is suspended from the hoisting device to be lowered towards the sea bottom, wherein the first bulk material shuttle is provided with a first bulk material container for carrying inserted bulk, wherein the dumping vessel further comprises 10 a dosing device for release of the bulk material from the first bulk material container.

2. Dumping system according to claim 1, wherein the first bulk material shuttle is suspended from the hoisting device by one or more hoisting cables. 15

3. Dumping system according to claim 2, wherein the hoisting cables have an effective length of at least one-thousand meters.

4. Dumping system according to claim 2 or 3, wherein, when the hoisting cables for the first bulk 20 material shuttle are fully paid out with the first bulk material shuttle suspended thereof, the first bulk material shuttle is at a depth of at least one-thousand meters below sea level.

5. Dumping system according to any one of the 25 preceding claims, wherein the sea bottom facing end of the first bulk material container is provided with an opening, wherein the dosing device is placed in front of the opening in order to control the flow of bulk material from within the first bulk material container through the opening. 30

6. Dumping system according to any one of the preceding claims, wherein the vessel is provided with an umbilical cable having multiple conductors that connect the 6036838_1 (GHMatters) P91781.AU DENISET 23 first bulk material shuttle to a control unit on the hull.

7. Dumping system according to claim 6 when dependent on claim 5, wherein the dosing device is electrically and/or hydraulically powered, wherein the 5 dosing device is connected via the umbilical cable to the control unit on the hull.

8. Dumping system according to one any of the preceding claims, wherein the first bulk material shuttle is provided with at least one position detection device. 10

9. Dumping system according to claim 8 when dependent on claim 6, wherein the position detection device is connected via the umbilical cable to the control unit.

10. Dumping system according to claim 9 when dependent on claim 8, wherein the position detection device 15 is a sonar.

11. Dumping system according to any of the preceding claims, wherein the first bulk material shuttle is provided with at least one positioning device.

12. Dumping system according to claim 11 when 20 dependent on claim 6, wherein the positioning device is connected via the umbilical cable to the control unit.

13. Dumping system according to claim 11 or 12, wherein the positioning device comprises a sideway thruster, arranged to provide a thrust force that can move 25 the first bulk material shuttle in a horizontal plane.

14. Dumping system according to any one of claims 11-13, wherein the first bulk material shuttle is provided with multiple positioning devices, arranged to provide a combined thrust that can move the first bulk material 30 shuttle in any sideways direction in a horizontal plane.

15. Dumping system according to any one of the preceding claims, wherein the hull is provided with a bulk material storage and a transport assembly extending from the bulk material storage to the first bulk material 35 shuttle.

16. Dumping system according to claim 15, wherein 6036838_1 (GHMatters) P91781.AU DENISET 24 the first bulk material shuttle is provided with an open top end, wherein the transport assembly extends outside the hull to drop bulk material through the open top end of the first bulk material shuttle into the first bulk material 5 container of the first bulk material shuttle.

17. Dumping system according to any one of the preceding claims, comprising a second bulk material shuttle, which is suspended from the hoisting device to be lowered towards the sea bottom, wherein the hoisting device 10 is arranged for descending and ascending the first bulk material shuttle and the second bulk material shuttle in mutually opposite directions.

18. Dumping system according to claim 17, wherein the first bulk material shuttle and the second bulk 15 material shuttle are interconnected via the hoisting device so that when the first bulk material shuttle descends, the second bulk material shuttle ascends, and vice versa.

19. Dumping system according to any one of the preceding claims, comprising a remotely operated 20 submergible vehicle, wherein the vessel is provided with an umbilical cable having multiple conductors that connect the remotely operated vehicle to a control unit on the hull, wherein remotely operated vehicle is provided with a positioning device and a position detection device, wherein 25 the remotely operated vehicle comprises a connector for connecting the remotely operated vehicle to the first bulk material shuttle.

20. Dumping system according to claim 18, wherein the remotely operated vehicle is provided with an interface 30 that interfaces with the dosing device of the first bulk material shuttle while the remotely operated vehicle is connected to the first bulk material shuttle, for operating the dosing device.

21. Method for dumping bulk materials on the sea 35 bottom for supporting a subsea infrastructure or on a subsea infrastructure on the sea bottom with a dumping 6036838_1 (GHMatters) P91781.AU DENISET 25 system comprising a dumping vessel with a floating hull provided with a hoisting device, and a first bulk material shuttle which is suspended from the hoisting device to be lowered towards the sea bottom, wherein the first bulk 5 material shuttle is provided with a first bulk material container for carrying inserted bulk, wherein the dumping vessel further comprises a dosing device for release of bulk material from the first bulk material container, wherein the method comprises the following steps; filling 10 the first bulk material container with bulk material, submerging the first bulk material shuttle, having the first bulk material shuttle descent suspended from the hoisting device towards the sea bottom, having the dosing device release the bulk material from the first bulk 15 material container, letting the bulk material drop from the first bulk material shuttle on to the sea bottom.

22. Method according to claim 21, wherein the first bulk material shuttle comprises at least one positioning device, wherein dumping system comprises a 20 control unit, wherein the method comprises the step of controlling the positioning device with the control unit to position the first bulk material shuttle relative to the hull and/or relative to the sea bottom and/or relative to an object on the sea bottom. 25

23. Method according to claim 21 or 22, wherein the first bulk material shuttle comprises at least one position detection device, wherein the method comprises the step of detecting the position relative to the hull and/or the sea bottom and/or an object on the sea bottom with the 30 position detection device.

24. Method according to any one of claims 21-23, wherein the dumping vessel comprises a bulk material storage inside the hull and a transport device, wherein the first bulk material shuttle is provided with an open top 35 end, wherein the method comprises the following steps; submerging the first bulk material shuttle suspended from 6036838_1 (GHMatters) P91781.AU DENISET 26 the hoisting device until the open top end of the first bulk material shuttle is below and in proximity of the water line, transporting bulk material with the transport device from the bulk material storage to the first bulk 5 material container, and dropping bulk material trough the open top end of the first bulk material shuttle into the first bulk material container.

25. Method according to any one of claims 21-24, wherein the dumping system comprises a second bulk material 10 shuttle, which is suspended from the hoisting device to be lowered substantially parallel to the first bulk material shuttle towards the sea bottom, wherein the method further comprises the following steps; having the hoisting device descend the first bulk material shuttle while the second 15 bulk material shuttle ascends and vice versa.

26. Method according to claim 25, wherein the dumping system comprises a remotely operated submergible vehicle, wherein the vessel is provided with an umbilical cable having multiple conductors that connect the remotely 20 operated vehicle to a control unit on the hull, wherein remotely operated vehicle is provided with a positioning device and a position detection device, wherein the remotely operated vehicle comprises a connector for connecting the remotely operated vehicle to the first bulk 25 material shuttle, wherein the method further comprises the following steps; connecting the connector of the remotely operated vehicle to the first bulk material shuttle in its descended position, positioning the first bulk material shuttle above a target on the sea bottom, releasing the 30 bulk material from the first bulk material shuttle, terminating the connection between the remotely operated vehicle and the first bulk material shuttle, connecting the connector of the remotely operated vehicle to the second bulk material shuttle in its descended position, 35 positioning the second bulk material shuttle above a target on the sea bottom, releasing the bulk material from the 6036838_1 (GHMatters) P91781.AU DENISET 27 second bulk material shuttle and terminating the connection between the remotely operated vehicle and the second bulk material shuttle. 6036838_1 (GHMatters) P91781.AU DENISET