When the crew on board a small fishing vessel offshore from Dubai saw a coast guard speedboat racing through the darkness, they prepared for the worst, hoisting an iron shield on the bridge in an improvised attempt to guard against potential gunfire.
Their vessel, the Meigou-4, sailed from Iran to United Arab Emirates waters every day to meet another boat with a motorised hose pipe to draw out its cargo of Iranian fuel - a process known as ship-to-ship transfer that is a fundamental part of a vast smuggling network that generates each year.
