Nearshore Pre-Lay Grapnel Run for BorWin6 cable system
Overview
OEG’s subsea team was contracted to provide pre-lay grapnel runs (PLGR) on the nearshore cable system prior to the cable laying campaign on of the offshore grid connection project BorWin6 of TenneT Germany.
BorWin6 enables the connection of an offshore wind farm to the German extra-high voltage grid. Therefore at sea, the wind power is converted into direct current on a converter platform, transported ashore via cables, converted back into alternating current and fed into the German extra-high voltage grid.
Challenges
The client required pre-lay grapnel runs on a nearshore section of the BorWin6 cable system, prior to the arrival of a cable laying vessel for the next phase of the project.
The location was particularly challenging for this work scope, with the nearshore section of the cable system crossing the UNESCO listed world heritage area of the Wadden Sea, which is the largest intertidal flats system in the world.
Workscope
OEG’s subsea team delivered a successful PLGR campaign for Nexans, utilising a specialist vessel with a very low draft to navigate the challenging intertidal location.
Solution
OEG’s complete solution was inclusive of grapnel runs, vessel operations and crew, survey equipment, specialist grapnels and the supply of experienced project management and survey personnel.
Throughout the work scope, the project team were able to complete grapnel runs up to the required 1.5m in depth in the shallow waters, as a result of careful planning and scheduling of operations around the restricted windows for suitable tide conditions. The project team was mobilised with a short notice period, with operations commencing less than 7 days following contract award.
The use of a specialist vessel equipped with a crew who had local knowledge of the intertidal location enabled the project team to deliver a successful work scope within the required time frame. OEG’s use of specialist grapnels and experienced personnel ensured deep penetration on the grapnel runs, successfully clearing the cable corridor of debris and preparing the site for the cable laying vessel.
OEG’s integrated services allowed the subsea team to deliver a seamless and efficient solution to the client, by utilising our in-house teams of survey experts, specialist equipment and experienced project personnel.
Testimonial
“OEG executed the nearshore Pre-Lay Grapnel Run for the BorWin6 cable installation project on behalf of Nexans. The operation was completed safely and on schedule under challenging shallow-water conditions and within a strictly regulated environmental framework. OEG provided a comprehensive method statement prior to the PLGR and ensured transparent communication and full compliance with environmental and operational requirements throughout the work. Nexans appreciates the professional collaboration and successful execution of this phase.”