Device, system and method for protecting a subsea mooring chain from corrosion

Abstract

A device, a system and a method are for protecting a subsea mooring chain from corrosion. The system has the device as well as an installation tool and an ROV having a manipulator arm for bringing the device close to the chain. The device has at least one sacrificial anode and a clamp for carrying the at least one sacrificial anode, the clamp having a jaw for releasably connecting the sacrificial anode to the mooring chain.

1 . A device for protecting a subsea mooring chain from corrosion, the device comprising at least one sacrificial anode, wherein the device further comprises a clamp for carrying the at least one sacrificial anode, the clamp having a jaw for releasably connecting the sacrificial anode to a chain link of the mooring chain and establishing electrical contact between the sacrificial anode and the chain link. 
     
     
         2 . The device according to  claim 1 , wherein the at least one sacrificial anode comprises a plurality of sacrificial anodes. 
     
     
         3 . The device according to  claim 1 , wherein the at least one sacrificial anode is releasably connected to the clamp. 
     
     
         4 . The device according to  claim 1 , wherein the device is configured for ROV operation. 
     
     
         5 . A system for protecting a subsea mooring chain from corrosion, the system comprising the device according to  claim 1 , an installation tool, and an ROV. 
     
     
         6 . A method of protecting a subsea mooring chain from corrosion, the method comprising:
 arranging the device according to  claim 1  on an installation tool connected to an ROV;   bringing the ROV close to the subsea mooring chain;   connecting the device to a first link on the mooring chain; and   releasing the installation tool from the device, leaving the device connected to the chain link.   
     
     
         7 . The method according to  claim 6 , further comprising:
 arranging a further device on the installation tool; and   connecting the further device to a second link of the mooring chain.   
     
     
         8 . The method according to  claim 7 , wherein the second link is separated from the first link by at least one chain link. 
     
     
         9 . The method according to  claim 8 , further comprising:
 estimating an optimal number of chain links between the first link and the second link based on at least one of: the corrosivity and the conductivity of the water.   
     
     
         10 . The method according to  claim 6 , further comprising:
 re-connecting the installation tool to the device for detaching the device from the chain link.   
     
     
         11 . The method according to  claim 6 , further comprising the step:
 replacing the at least one sacrificial anode with a new sacrificial anode, via the ROV.