Star Canopus diving accident

The Star Canopus diving accident was an incident in Scotland in November 1978 that killed two British commercial divers. During a routine dive beside the Beryl Alpha platform in the North Sea, the diving bell of the diving support vessel MS Star Canopus was lost when its main lift wire, life support umbilical, and guide wires were severed by an anchor chain of the semi-submersible Haakon Magnus. The bell dropped to the seabed at a depth of over 100 metres (330 ft). Its two occupants, 25-year-old Lothar Michael Ward and 28-year-old Gerard Anthony "Tony" Prangley, were unable to release the bell's drop weight in order to return to the surface because it was secured to the bell frame with secondary locking pins. Since there was not a bell stage to keep the bottom door of the bell off the seabed, the divers could not exit the bell to release the pins. Despite the efforts of three rescue vessels – Intersub 4, Tender Carrier, and Uncle John – the bell was not recovered for over thirteen hours, by which time Ward and Prangley had died of hypothermia and drowning.

Background

On 26 November 1978 the Diving Support Vessel Star Canopus was dynamically positioned on the northeast side of the Beryl Alpha platform conducting diving operations. 334 feet (102 m) below, Michael Ward was working for Northern Divers about 60 feet (18 m) off the seabed trying to connect a 6-inch (150 mm) flow line to a riser flange protruding from the side of the concrete platform.

Oil production had declined that year, and with winter conditions upon them, subsea work had fallen behind schedule. There was "a lot of catching up to do", Martin Dane, the Contracts Manager for Northern Divers would say later, and Mobil Oil, like many operators, decided to allow the diving program to continue through the winter months to take advantage of available weather windows.