James Fisher Subsea (JF Subsea), part of James Fisher and Sons plc, provided expertise for a project to locate, identify and dispose of deep-sea unexploded ordnance (UXO) at Nordergründe offshore wind farm located 16 kilometers off the North Sea coast of Germany.



Offshore wind farm development and management specialists wpd offshore solutions approached JF Subsea to use its excavation techniques to survey the precarious area and remove all unexploded munitions. The UXOs, which had been released by Central Powers and Allied forces during WWI, had delayed planned construction works and was at risk of costing the developer millions as a result.



Of the 224 targets identified, 72 were deemed to be UXOs and had to be detonated with minimal impact to sea life. JF Subsea’s project manager, Max Clements, said, “Due to the project’s potentially dangerous complexities- such as rough tide, heavily buried ordnance and inclement weather- the team was prepped to be ready at a moment’s notice whenever a suitable weather window opened up.”



“As with all UXO operations safety was of the upmost priority and from the planning stages we ensured we had project specific equipment, world-class expertise and encompassing method statements in place. These measures ensured the teams were safe, the UXO’s were removed efficiently and the client received a world class service,” Clements added.



Due to the complex and unpredictable nature of the project, JF Subsea said it had to work within narrow weather windows and often in shallow waters with rough tides. Target location, ROVs, detonation specialists and bespoke UXO support vessels were all used as part of a turnkey solution, ensuring the precise and efficient delivery of the project.



Two vessels were deployed for the duration on the project, with specialist divers used to locate and remove the UXOs during the day and ROVs dispatched to detect and excavate through the night. This dual-pronged approach sped up the clearance process and reduced the delay to the client’s start date.



“Offshore wind turbine sites are often plagued with UXOs and are a continual problem we come up against during construction. Due to the expertise JF Subsea showed throughout the excavation process we will most likely be using their services again,” said Jan Patrick Daniel, offshore project manager at wpd.