On November 25th the Elva, a tanker flagged in São Tomé and Príncipe, clandestinely picked up 2m barrels of Iranian crude off Malaysia’s coast. Sailing from there to north-east China, the vessel’s likely destination, usually takes two weeks at most. But not this time. On December 3rd, alleging the Elva had breached sanctions, America blacklisted the ship, exposing anyone dealing with it to punishment. Six weeks on it is still stranded less than 20km from where it collected its cargo.