Scottish Power engineers find lost wreck of German WW1 submarine in offshore windfarm sea-bed survey

Scottish Power renewables engineers found German UI-Boat 31 in their windfarm sea-bed survey
Scottish Power renewables engineers found German UI-Boat 31 in their windfarm sea-bed survey

EXCLUSIVE report by Scottish Energy News

Scottish Power wind farm engineers have discovered the ‘lost’ wreck of a World War One German submarine in the North Sea while carrying out sea-bed surveys for a new wind farm development.

The uncharted submarine – missing in action for 101 years – sank off the East Anglia coast in 1915, which is where Scottish Power and co-developer Vattenfall plan to build new offshore wind farms in the East-Anglia-1 development.

Charlie Jordan, Scottish Power Renewables’ project director for the East Anglia-1 windfarm, said: “The scanning team were expecting to see wrecks, but this discovery was quite a surprise and has been extremely interesting.”

“We used advanced sonar technology to scan over 6,000km2 of the seabed in the Southern North Sea over two years, which is nearly four times the size of Greater London. This work is critical to understand seabed conditions, and allow the companies to design the layout of their proposed projects.

“Although more than 60 wrecks were discovered during the scanning work, most of these were anticipated, but the uncharted submarine 90km from shore was entirely unexpected.”

Andy Paine, Vattenfall project director of East Anglia Offshore Wind Farm, added: “Following the discovery the team reported its findings to the relevant authorities, including RoW (Receiver of Wreck) in the UK. The seabed scanning had been undertaken by Netherlands-owned company Fugro, and their team made us aware of the Dutch Navy’s hunt for its last remaining missing WWII submarine.

“We were all extremely keen to make contact with the Dutch Navy to see if this could be the submarine they have been looking for over so many years: could we at last have solved the mystery?”

The Royal Netherlands Navy was duly notified to investigate whether it was Dutch military submarine HNLMS O13, which went missing in action in June 1940, after the crew were tasked to patrol the waters between Denmark and Norway.

The wreck discovered within the East Anglia Zone is 57.6 metres in length, 4.1 metres in width and 4.6 metres in height and the bow appears to be facing south. Damage was observed at the bow and the stern, so the original length could be slightly longer than it appears and debris surrounding the wreck suggests a more likely length of over 60 metres (but less than 70m).

GoPro footage taken by the Dutch Navy divers highlighted clear images of the conning tower and deck lay-out, which suggested the wreck was of German origin. From German drawings it was identified as a WWI German submarine – Type U-31. A database of reference books shows that only U-boats U-31 and U-34 had been lost in this area of the North Sea.

Commander (Retired) Jouke Spoelstra of the RNLNavy/Submarine Service, who heads up project ‘Search for O-13’ said: “Whilst it was disappointing from our perspective when we realised the wreck was not that of O-13, we conducted several dives with divers of the minehunter HNLMS Makkum and with a REMUS UAV sonar team with the aim to achieve clearer footage of the wreck and undertake investigative work to ascertain its identity.

“It wasn’t an easy job and several dives were required before any real progress was made due to the sea conditions surrounding the site meaning we couldn’t obtain any evidence revealing the exact identity.

“Fortunately on a recent dive undertaken by the Lamlash North Sea Diving team they had good conditions and so were able to achieve clear footage and finally identify the wreck.”

Three years after its initial discovery the wreck was officially identified as German submarine, U-31, which left for patrol on 13 January 1915 never to return. The wreck is approximately 90km offshore in the North Sea but sits on the seabed at a depth of only 30 metres.

Mark Dunkley, marine archaeologist at Historic England said: “SM U-31 was commissioned into the Imperial German Navy in September 1914. On 13 January 1915, the U-31 slipped its mooring and sailed north-west from Wilhelmshaven for a routine patrol and disappeared.

“It is thought that U-31 had struck a mine off England’s east coast and sank with the loss of its entire complement of four officers and 31 men.”

“The discovery and identification of SM U-31 by Scottish Power Renewables and Vattenfall, lying some 91km east of Caister-on-Sea, Norfolk, is a significant achievement. After being on the seabed for over a century, the submarine appears to be in a remarkable condition with the conning tower present and the bows partially buried.”

As an official military maritime grave, the wreck of U-31 will remain in its final resting place and plans for any offshore windfarm development will be progressed ensuring no disturbance to the area.

Scottish Power Renewables LIDAR deployed off Norfolk at its East Anglia-1 wind farm project
Scottish Power Renewables LIDAR being deployed off Norfolk at its East Anglia-1 wind farm project

Scottish Power Renewables is currently developing East Anglia-1 in the southern area of the zone, which will be the first windfarm to be constructed. Construction will commence in 2017 and the windfarm will be fully operational in 2020, providing power to over 500,000 homes.

Meanwhile, Scottish Power has successfully installed a pioneering floating wind monitoring device in its East Anglia-1 wind farm zone.

In the last few weeks a floating LiDAR (Light Detection and Ranging) system has been deployed to test and validate wind, wave and climate data.

Floating LiDAR devices could ultimately replace the need for traditional steel lattice meteorological masts if trials prove to be successful, and vastly reduce costs. Based on a traditional buoy design, the floating LiDAR system is equipped with a range of advanced monitoring technology. The device is compact, mobile and easy to install, so it can be moved around easily within the windfarm site. There is also minimal impact on the seascape and no requirement for planning permission.

Fugro is supplying all the equipment being used in the test project. Previously the company has undertaken investigative work on the East Anglia-1 windfarm site, including a shallow geological survey of the export cable route and along the 26 miles to shore, and deeper geotechnical investigations for the turbine foundation design.

Local vessel, The Suffolk Spirit, assisted with the installation process, which was also supported by Small & Co, a Lowestoft-based marine engineering company.

Charlie Jordan said: “The floating LiDAR concept has the potential to deliver major benefits for the entire offshore wind industry, not least by offering substantial cost reductions. We are committed to driving down costs in all aspects of delivering an offshore windfarm, and this trial project in East Anglia will play a key role in proving the advantages of the new technology”

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