When Washington announced the return of economic sanctions against Iran, the main idea was pretty clear: cut exports of vital oil to zero to paralyze the economy and prompt a change in government. Waivers followed, however, as well as reports that, despite the sanctions, Iran was shipping more oil abroad than the amounts allowed under the waivers. Oil data provider TankerTrackers.com first reported last year that Iranian tankers were turning off their transponders to hide the destination of their journeys. At the time, most tanker tracking data came precisely from transponders and port authorities, which made most Iranian tanker movement reports unreliable. This, in turn, contributed to the October-December oil price drop when it emerged that Iran was shipping more crude abroad than previously believed. No wonder, then, that the United States is now targeting vessels transporting Iranian crude oil in violation of sanctions, a senior State Department official […]