The shadow fleet and illegal oil are still moving through the Strait of Hormuz | Fortune

"In maritime circles, these vessels are called the 'shadow fleet.' They are vessels that ignore international restrictions on trade with certain countries, violate anti-pollution regulations, smuggle unauthorized goods or don't want their cargo or activities too closely monitored. They exist, even in a world filled with electronic tracking, because the world's oceans aren't governed the same way the land is."

"The system that governs international shipping is, at its foundation, voluntary. The tracking of ships is voluntary. The International Convention for the Safety of Life at Sea - signed by 167 countries - requires almost every commercial vessel to carry a radio transponder that broadcasts the ship's identity, position, speed and heading to port authorities, coast guards and commercial tracking networks."

"That international agreement, which is enforced by individual countries, requires ships to leave the transponders on and active. But there is no physical mechanism preventing a crew from switching it off or broadcasting a false position. When a vessel turns off its transponder and goes dark, it doesn't..."

Iran has threatened to destroy ships passing through the Persian Gulf strait, causing insurance companies to reconsider coverage and international maritime bodies to inform crews of their right to refuse passage. Over 400 tankers remain stranded without owner permission to move. However, vessels operating outside international rules—known as the 'shadow fleet'—continue transiting the area. These ships ignore trade restrictions, violate anti-pollution regulations, smuggle goods, or avoid cargo monitoring. The shadow fleet exists because maritime regulation operates on a voluntary basis, unlike land-based governance with armed border enforcement. International shipping tracking relies on voluntary transponder systems that crews can disable or manipulate without physical prevention mechanisms.

Read at Fortune