Noble Corporation plc is an offshore drilling contractor for the oil and gas industry. The Company performs contract drilling services with its global fleet of mobile offshore drilling units. As of December 31, 2016, the Company's fleet of 28 drilling rigs consisted of 14 jackups, eight drillships and six semisubmersibles. The Company's drillships are self-propelled vessels. These units maintain their position over the well through the use of a computer-controlled dynamic positioning system. As of December 31, 2016, its drillship fleet consisted of four dynamically positioned Gusto Engineering Class drillships; two dynamically positioned Bully-class drillships, and two dynamically positioned Globetrotter-class drillships. As of December 31, 2016, its semisubmersible fleet consisted of two Noble EVA-4000 semisubmersibles; two modified Friede & Goldman 9500 Enhanced Pacesetter semisubmersibles, and two modified Bingo 9000 design unit, dynamically positioned semisubmersibles.