Practical Boat Owner: An uncharted wreck of a WWI German submarine, missing in action since 1915, has been officially identified three years after being discovered off the coast of Norfolk and Suffolk.
Survey teams from windfarm developers ScottishPower Renewables (SPR) and Vattenfall spotted the wreck in September 2012 while seabed scanning for the development of windfarm projects in the East Anglia Zone.
Yesterday it was announced that the wreck has been 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.
SPR and Vattenfall used advanced sonar technology to scan over 6,000km2 of the seabed in the Southern North Sea over two years.
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.
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 that this was 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.
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.