Byford Dolphin is a semi-submersible, column-stabilised drilling rig operated by Dolphin Drilling, a Fred Olsen Energy subsidiary. The Byford Dolpin came into service in 1974 as the Deep Sea Driller before changing it's name to Byford Dolphin in 1978. The rig has suffered some serious accidents, most notably an explosive decompression in 1983 that killed four divers and one dive tender, and badly injured another dive tender. More Information