JF Marine Services delivers innovative UXO solution on German renewable project.
James Fisher Marine Services delivers innovative solution for unexploded ordnance (UXO) on German renewable project for Vattenfall.
In recent months progress on building offshore wind farms in parts of the North Sea have been hampered by the discovery that many sites are littered with UXO dropped by Allied and German planes, ships and submarines during World War II. A James Fisher team, however, is quickly growing a firm reputation as an effective ‘bomb-buster’ unit in the area, having devised a solution which saves customers time and money.
Earlier this year, renewables company, Vattenfall, called in JF Subsea to work with German partner company GSS Hansa Offshore, to help clear the 'Sandbank' area, 90km off the coast of Germany.
A previous survey had identified a number of metal objects lying on the seabed and others buried up to 2.5 metres deep in the sand. Our team was asked to relocate the objects, to excavate them and dispose of any UXOs safely.
Martin Muntingh, managing director at JF Subsea explained:
"Our first task was to launch ROVs to find out which of these objects could actually be UXOs. The buried objects were cleared – carefully - using a ‘zip pump’ to suck away the sand, and we then called in a specialist to identify them and advise on an appropriate course of action."
Adrian Dann, formerly Lt Commander with the Royal Navy and one of the leading technical authorities on UXO disposal in the UK, was called in to help with detection and detonation working alongside the GSS Hansa Offshore German Para 20 technicians.
Of the 120 targets, 28 turned out to be unexploded ordnance which had to be safely detonated with minimal impact to sea life in the area. The project received high praise for speedy completion with the team exceeding identification and detonation targets, identifying as many as 12 devices in one day.
Significant time and money was saved by the choice of vessel which performed both identification AND disposal allowing the team to switch quickly between the two as required.
The operation was co-ordinated by project services manager Gary Hitchcock, and overseen by technical diving director, Bob Macmillan, who explains how the UXOs were exploded with minimal disruption to sea life:
"We use high frequency sound waves to ward off marine life, then set up a ‘bubble curtain’ (a hose laid on the seabed to encircle the site, which sends off a wall of air bubbles) to clear the blast radius and prevent damage to the local area."