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 seab