Electric fencing, sonic guns and even armed mercenaries are being offered as the first line of defence for ships at risk in pirate-infested waters. The world of private security and mercenary soldiers has been put on alert this week by the seizure of the supertanker Sirius Star. The tanker industry, however, is resisting any introduction of weaponry on vessels that are little more than floating petrol bombs. Frontline, a leading owner of oil tankers, has called for a multinational force to be sent to the Gulf of Aden to protect the access route to the Suez Canal. Fleet owners want...