The US's move to punish a Russian oligarch is also punishing shipowners, with bulker operators Oldendorff and MUR joining those pulling back from charterer Rusal as the global aluminium supply chain faces the biggest disruption in years.

At the start of April, the US Treasury Department put Oleg Deripaska on its growing sanctions list, accusing him of involvement in a host of alleged Russian government predations, including Ukraine and Syria, as well as crimes against business rivals.