The Gabon-registered ship, capable of carrying some 700,000 barrels of crude oil, was coming through the South China Sea after offloading a cargo in China — and so was nearly empty. Out of its international crew of 28, officials report that 25 were rescued by passing vessels. There is little evidence of the owner, a Marshall Islands-registered company whose fleet contains no other ships, and no trace of insurance. An Aframax-class crude oil tanker observed in Iranian waters last year, the Pablo underlines the risks that come with the expansion of a dark fleet of aging vessels moving sanctioned oil around the globe. The explosion has made the ship unsafe to board, leaving it stuck off the country’s coastline for the time being.