A US Coast Guard (USCG) investigation has found that a “chain of errors” led to the Royal Dutch Shell PLC conical drilling unit, the Kulluk, running aground on Sitkalidak Island, Alas., in December 2012 ( OGJ Online, Jan. 2, 2013 ). The primary cause was attempting a winter voyage in the Arctic with ineffective risk assessment and management, according to USCG’s report, which was released Apr. 2. The Kulluk broke free while being towed in heavy seas by Edison Chouest Offshore’s vessel, the Aiviq. There was no oil spill associated with the incident. The drilling unit was later salvaged and towed to an Asian dry dock for inspection and repairs. ( OGJ Online, Feb. 13, 2013 ). Complex series of events USCG’s investigation report describes a “complex series of events” that included inclement weather, seas of 20 ft, an inadequate tow plan, the Kulluk’s conical hull (see figure, OGJ, […]