Offshore Marine Management (OMM) has completed a contract related to HVDC cable laying for the Sylwin 1 project in German waters.
Prior to the installation of the cable, using the DP2 vessel,Vos Sweet, OMM cleared the route proposed for the 160km (77 miles) high-voltage direct current export cable that will connect the new wind parks to the onshore grid. This involved identifying and retrieving out-of-service cables along the route for later safe disposal onshore.
OMM conducted mattressing of the existing in-service underwater assets, including telecommunication and electricity cables as well as gas pipelines. Using a remotely operated underwater vehicle launched from the vessel, OMM’s team conducted a detailed survey of the sea bed, before identifying the correct position for each mattress and then releasing each into its location. A post-installation survey confirmed that no interference with third-party assets had taken place.
Finally, OMM used theBlue Capellato conduct a pre-lay grapnel run (PLGR) to clear the seabed of debris and other unwanted materials such as fishing lines. This ensured the route for the new Sylwin cable was clear and in good condition for cable installation.
In satisfying Prysmian’s requirements, Chief Operating Officer Eckhard Bruckschen commented: ”Despite challenging weather and some difficult seabed conditions, the out-of-service cables were successfully recovered and the route was proved clear in advance of the commencement of the cable lay. This proves the depth of service to our clients.”
Press release, February 20, 2014; Image: tennet