Vattenfall is about to kick off new seabed surveys at the sites of the 350MW Vesterhav North and South offshore wind complex off the coast of Denmark.

Two vessels – Olympic Delta (pictured) and Katabatic – will be deployed to seek unexploded ordnance, as well as allow Archaeologists from the Strandingsmuseum St George in Thorsminde to examine up to three possible shipwrecks in the area.

Vattenfall senior geophysicist Dorthe Reng Erbs-Hansen said that a geophysical survey of the wind farms sites was carried out in 2017 and found 22 points of interest.

The 2017 work also discovered magnetic field changes that were unclear, he added.

“In general, it is expected that one to 5% of the fields you have designated are dangerous objects, but we often find other interesting things like old anchors and maybe old shipwrecks,” Erbs-Hansen said.

“One of the findings is definitely a shipwreck. We have a nice picture of it, but do not know what it's like and when it fell,” he said.

If the vessel wreck is over 100 years old it will be protected and a wider safety radius will need to be employed when building the wind farms, Vattenfall said.

Two other sites found during the previous survey could also be shipwrecks, but have yet to be confirmed, the company added.

The new surveys will last two to three weeks after which Olympic Delta will move to the site of the 600MW Kriegers Flak offshore wind farm, also off the Danish coast.