The EU’s ban on such maintenance, agreed earlier this year, will not take effect until January, meaning the work remains legal for now. But campaigners argue every overhaul helps preserve one of the Kremlin’s most valuable sources of export revenue.

“As the only shipyard in the EU that continues to service the specialized Arc7 ice-class LNG carriers, it is effectively helping sustain Russia’s Arctic LNG exports,” Vladyslav Vlasiuk, Ukrainian President Volodymyr Zelenskyy’s adviser for sanctions policy, said this week.

Because the specialized vessels typically undergo major overhauls only once every two to three years, maintenance carried out this summer could keep them sailing long after European companies are no longer allowed to service them, reducing the practical impact of the sanctions before they even take effect.

“This is kind of the last hurrah,” said Malte Humpert, a shipping expert and investigative journalist. “If you know you’ll no longer be able to service these vessels in Europe from January, you’ll try to get as much maintenance done as possible now so you don’t have to worry about them for the next few years.”

The Rudolf Samoylovich arrived at Fayard on June 30, according to navigational data. The ship is one of the 15 Arc7 carriers that transport LNG from Russia’s massive high Arctic Yamal project. Environmental campaigners from German NGO Urgewald say it is the first of up to six vessels expected to undergo maintenance at the Danish yard this summer.

Summer is the fleet’s final major maintenance window thanks to the seasonal Arctic sea ice retreat, which allows conventional LNG carriers to temporarily replace the specialized vessels on parts of the route. Unlike conventional LNG tankers, Arc7 vessels are icebreaking ships designed to operate year-round through Arctic waters.