Offshore UXO survey  

During the construction wind farms, the laying of cables and dredging activities in the seabed there is always the risk of encountering unexploded ordnance (UXO) from the Second World War. In suspect areas it is therefore necessary to carry out an offshore UXO survey before starting the activities.  

To carry out offshore UXO surveys, T&A Survey has a team of specialized ex-marine UXO experts and certified divers. The UXO experts also take a leading role during the implementation of the project. If, for example, during dredging activities an object gets stuck in the suction nozzle, they can identify and secure the object on the spot. This way extra expenses due to stagnation of the activities can be significantly reduced.  

The offshore UXO survey is performed from a ship using an ROV (remotely operated underwater vehicle) and/or AUV (auronomous underwater vehicle) and several measuring techniques. The ROV for example is equipped with a rack of 8 to 12 gradiometer probes, a shortrange sonar and camera.  

T&A’s UXO experts start with the data analysis on board of the ship. By combining all the measurement results, suspect objects can be located with great accuracy. Based on the outcome, the principal can make the decision, if necessary, to relocate the activities or have the objects identified and removed.

'Controlled explosion' for WW2 wind farm bomb - BBC News, 24-03-2014