The Hibernia Gravity Base Structure is an offshore oil platform on the Hibernia oilfield southeast of St. John's, Newfoundland, Canada.
A 600-kilotonne gravity base structure (GBS) built after the Ocean Ranger disaster, it sits in 80 metres (44 fathoms) of water directly on the floor of the North Atlantic Ocean 315 kilometres (196 mi) off St. John's, Newfoundland at 46°45′1.57″N 48°46′58.54″W / 46.7504361°N 48.7829278°W.
This GBS is designed to resist iceberg forces and supports a topsides weighing 39,000 tonnes at towout, increasing to 58,000 tonnes in operation. There were significant challenges faced by the engineering firms Doris Development Canada, Morrison Hershfield and Mobil Technology in developing a structural solution with adequate strength which was also constructible. In addition, unusual design situations resulted from the construction methods and the structural components used.