Top oil shipping companies say they have tightened operational guidelines and deployed technology to prevent accidental breaches of sanctions, as the countries hit by ever tougher restrictions fight back with elaborate strategies to dodge them. Washington has ramped up shipping-related sanctions over the last two years to make it harder for countries, such as Iran and Venezuela, to export the oil that provides their main source of revenue. In response, Iran and Venezuela have developed sophisticated methods to bypass sanctions, which are also imposed to a lesser extent by the European Union. As a result, it is harder for shipping firms to avoid facilitating blacklisted exports unwittingly, potentially laying them open to being cut off from the U.S. financial system or even having assets […]