Device and method for performing an operation on an at least partially submerged structure

Abstract

A device ( 10 ) for performing an under water operation on an at least partially submerged structure ( 40 ) or in the vicinity of the at least partially submerged structure includes a base ( 15 ) including at least one coupling ( 20 ) for coupling the device to the structure; at least a first articulated movable arm ( 30 ) directly or indirectly connected at a proximal end thereof ( 31 ) to the base, the first movable arm including a tool ( 60 ) connected to a distal end ( 29 ) of the first movable arm, where the tool is movable in a three dimensional working range about the base, where the base includes at least one rail ( 22 A, 22 B), and where the movable arm ( 30 ) includes a support carriage ( 32 ) which engages with the rail in order to allow the movable arm to move along the rail.

1 . A device for performing an under water operation on an at least partially submerged structure or in the vicinity of the at least partially submerged structure, the device comprising:
 a base comprising at least one coupling for coupling the device to the structure and uncoupling the device from the structure; and   at least a first articulated movable arm directly or indirectly connected at a proximal end thereof to the base, the first movable arm comprising a tool connected to a distal end of said first movable arm, wherein the tool is movable in a three dimensional working range about the base;   wherein the base comprises at least one rail; and   wherein the movable arm comprises a support carriage which engages with the rail in order to allow the movable arm to move along said rail.   
     
     
         2 . The device according to  claim 1 , wherein the base comprises a buoyancy element. 
     
     
         3 . The device according to  claim 2 , wherein the buoyancy element is elongate and wherein the couplings are connected to the buoyancy element at different positions along the length of the buoyancy tank. 
     
     
         4 . The device according to  claim 1 , wherein the buoyancy element is elongate and constructed to be mounted to a leg of the structure in an orientation which is substantially parallel to said leg. 
     
     
         5 . The device according to  claim 1 , wherein the base comprises a first rail and a second rail which extend parallel to one another at a distance from one another, wherein the support carriage is constructed to engage both the first and the second rail. 
     
     
         6 . The device according to  claim 5 , wherein the at least one rail is mounted to the buoyancy element. 
     
     
         7 . The device according to  claim 4 , wherein the buoyancy element has a longitudinal axis, wherein the at least one rail extends parallel to the longitudinal axis of the buoyancy element. 
     
     
         8 . The device according to  claim 3 , comprising a plurality of couplings which are mounted to one side of the buoyancy element, wherein the at least one rail is mounted to a different side of the buoyancy element. 
     
     
         9 . The device according to  claim 1 , comprising at least two movable arms, each comprising a support carriage and each being movably connected to the at least one rail, the at least two movable arms being movable over said rail independently from one another. 
     
     
         10 . The device according to  claim 9 , comprising two sets of rails, and wherein at least one movable arm is movably connected to each set of rails. 
     
     
         11 . The device according to  claim 1 , wherein at least one movable arm comprises a connection member constructed to be connected to a lifting cable which extends between a surface vessel and the movable arm. 
     
     
         12 . The device according to  claim 11 , wherein the movable arm comprises at least two segments connected to one another by a hinge and wherein the connection member is provided near said hinge. 
     
     
         13 . An assembly comprising:
 a device according to  claim 1 ;   a vessel; and   an at least partially submerged structure;   wherein the device is connected to the structure, wherein the vessel is connected to the connection member via a lifting cable, wherein the vessel exerts an upward force on the movable arm via the lifting cable.   
     
     
         14 . A method of performing an under water operation on an at least partially submerged structure or in the vicinity of the at least partially submerged structure, the method comprising:
 providing a device for performing an under water operation on an at least partially submerged structure or in the vicinity of the at least partially submerged structure, the device comprising:
 a base comprising at least one coupling for coupling the device to the structure and uncoupling the device from the structure; and 
 at least a first articulated movable arm directly or indirectly connected at a proximal end thereof to the base, the first movable arm comprising a tool connected to a distal end of said first movable arm, wherein the tool is movable in a three dimensional working range about the base; 
   wherein the base comprises at least one rail, wherein the movable arm comprises a support carriage which engages with the rail in order to allow the movable arm to move along said rail;   connecting said device to the structure, wherein the base of the device is at least partially submerged; and   performing an operation with the tool mounted on the distal end of the movable arm.   
     
     
         15 . The method of  claim 14 , wherein the device comprises a buoyancy element, and wherein the method further comprises:
 transporting the device to the structure in a floating condition;   ballasting the buoyancy element with water, thereby lowering the device; and   connecting the device to the structure via at least two couplings;   wherein at least one coupling is located under water.   
     
     
         16 . The method of  claim 14 , wherein the buoyancy element is elongate and is connected substantially parallel to a leg of the structure. 
     
     
         17 . The method of  claim 14 , wherein the device comprises at least one rail, wherein the movable arm comprises a support carriage which engages with the rail and is constructed to move along said rail, wherein the movable arm travels along said rail from one position to another position, and performs operations at said positions. 
     
     
         18 . The method of  claim 14 , wherein the device comprises two or more movable arms which are movably connected to the at least one rail and which simultaneously perform operations on the structure, in particular in cooperation. 
     
     
         19 . The method of  claim 14 , further comprising:
 removing several parts of the structure by the movable arm, and leaving a leg to which the device is connected and supporting beams which directly support the leg intact.   
     
     
         20 . The method of  claim 14 , further comprising:
 positioning a vessel in the vicinity of to the device and providing one or more connection lines between the device and the vessel for conveying: control signals, electric power, and/or hydraulic fluids from the vessel to the device or vice versa.   
     
     
         21 . The method of  claim 14 , further comprising:
 positioning a vessel comprising a hoisting device above to the device and providing at least one lifting cable between the hoisting device and a connection member on the movable arm; and   performing an operation with the tool mounted on the distal end of the movable arm, wherein during the operation an additional lifting force (F) is exerted on the movable arm via the lifting cable by the vessel.