Before a subsea power cable can be laid, the route on the seabed must be clear of obstacles such as boulders and unexploded ordnance. This is particularly important in the Baltic Sea due to many archaeological objects and historical events. Apart from wrecks of submarines, ships or airplanes you can also find glider bombs on the seabed. To ensure safety, environmental protection and economic efficiency, 50Hertz checks the route of each subsea cable for unexploded ordnance. For the project in the Baltic Sea 50Hertz coordinates with the Munitions Recovery Service from the state of Mecklenburg-Vorpommern (MBD M-V).. Along the planned Ostwind 2 cable route, vessels survey a corridor for metallic objects and then inspection is carried out by ROV (remotely operated vehicles) or divers.
A rare find
During work on the cable route, a glider bomb was found in July. It was the Henschel Hs 293 - a remote-controlled glider bomb from the Second World War. It resembles a small airplane, has a wingspan of three meters and weighs just under one tonne.
Experts recover dangerous goods
Even 80 years later, these bombs can still be explosive or release toxic substances. Therefore, extreme caution is required during salvage. The companies and persons involved are specially qualified to recover explosive ordnance safely and in an environmentally friendly way.
The glider bomb was located in shallow water at a depth of approx. 4 metres and could be inspected by divers. A specialist diving company from Rostock recovered the aircraft bomb and handed it over to the Landesamt für Zentrale Aufgaben und Technik der Polizei Brand- und Katastrophenschutz M-V (LPBK M-V). The bomb was not explosive and will now be disposed professionally.
Besides the bomb recovery, five targets of metal scarps where found. With the completion of the explosive ordnance clearance in shallow water and the successful recovery of the unexploded ordnance, a further step was taken in the direction of cable laying at sea.