175,000 litres of oil and 120m of ghost nets successfully removed from WWII shipwreck

The ship Skytteren sank on April 1, 1942, about ten kilometres from the Swedish west coast near the city of Lysekil.  According to The Swedish Agency for Marine and Water Management’ s environmental risk assessment, the Skytteren is ranked as number one on the list of the 30 most environmentally hazardous wrecks.

In mid-September 2021, work began on extracting the 175,000 litres of oil still trapped inside the shipwreck. The Danish company JD Contractor was commissioned by Swedish Marine and Water Authority, HaV, which financed the work. The work was complicated and time consuming. It had to be paused during the winter due to bad weather. After about six days of intensive diving work at the end of April, the wreck has now been emptied of oil.

The Skytteren is located at a depth of about 74 meters with an occasional strong bottom and surface current. The wreck has been carefully examined on several previous occasions to make the salvage operation as efficient as possible. In November 2018, HaV carried out a major operation together with the Swedish Armed Forces. In the summer of 2020, further work was carried out. With a system camera mounted on an underwater robot, all parts of the wreck were digitally documented close-up with almost 27,000 overlapping images.

The remediation work has been carried out with the help of divers and an underwater robot. The divers have drilled into the spaces where the oil is located and then pumped it up to the work vessel at the surface. At some points the oil was too viscous to be pumped out. In order to extract this highly viscous oil, the tanks were heated allowing the remaining oil to be pumped out.

In addition to the oil, the wreck has also been cleaned of ghost nets. Six ghost nets with a total length of 120 – 180 meters have been removed from the sea.

HaV’s work with environmentally hazardous wrecks continues. More wrecks will be emptied of oil in 2022.