Off the west coast of Norway, Van Oord has successfully stabilized the wreck of a World War II submarine.
The Norwegian Coastal Administration awarded the contract to Van Oord at the end of 2015.
The wreck, containing toxic mercury, was located at the top of a steep slope in the seabed.
This slope was stabilized to guarantee the stability of the wreck.
Van Oord deployed its flexible fallpipe vessel Stornes. At a working depth of 150 meters, Van Oord built a foundation (counter fill) of 30,000 tonnes of sand and 160,000 tonnes of stone so that stability of the slope was guaranteed and the bow and surrounding sediments would not slide of the slope.
Preventing the spread of mercury to the environment was the main objective during the installation of the counter fill.
Van Oord developed a special installation method for the placement of the sand to minimize the disturbance of the seabed.
The Norwegian Institute for Water Research (NIVA) was subcontracted for the monitoring.