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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.
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.[citation needed]
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.
Earlier that evening, London Weather Center had predicted 40-knot gusts between 18:00 and midnight. That forecast proved to be correct. At 2030, and again at 2245, squalls reaching those speeds moved in and blew the Canopus off location. Shortly thereafter, Captain Roy Forsyth terminated diving operations. But when the 12-hour shift change occurred at midnight, weather conditions had calmed. Coming on duty, Supervisor Robert Kelly was instructed by diving superintendent Ed Hammond to continue with the dive program due to improved conditions.
The weather forecast now predicted that there would be a change in wind direction from west to north, and that conditions "would worsen later in the day" with wind speeds gusting to 35 knots. The Canopus was only a year old, and although it represented the latest and best technology of that era, the limits of her dynamic positioning system were 18–20 knots with the wind hitting her broadside.
Prior to the accident, the wind-speed indicator was fluctuating between 15 and 20 knots (28 and 37 km/h). Standing alongside the Beryl platform, near where the Canopus would be commencing work, was the Haakon Magnus, a Norwegian semi-submersible platform, with her massive anchor chains extended.[citation needed] Kelly determined the weather was suitable for diving and, at 0240, he launched the bell with Tony Prangley and Michael Ward inside.
At 0312, Ward locked out and found the pipe flange protruding from the wall of the platform base. Eight minutes later, Captain Forsyth called Kelly on the ship's intercom to alert him that a squall was approaching on the ship's radar. Kelly ordered Ward back to the bell where he sat for the next 40 minutes. At 0400 Ward was back on the job. Then, at 0545, the wind suddenly shifted directions and began blowing from the north at a speed of 40 knots, hitting the Canopus on her beam, and overpowering her dynamic positioning (DP) system. It was a sustained blow, the Contracts Manager would later testify:
When this wind arrived, it arrived really without any warning and it was not like a sudden gust of wind or a passing squall which then died down; it started blowing suddenly at 40 knots and remained at that level for a considerable period of time thereafter. It was a very strange occurrence, to say the least.
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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.
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.[citation needed]
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.
Earlier that evening, London Weather Center had predicted 40-knot gusts between 18:00 and midnight. That forecast proved to be correct. At 2030, and again at 2245, squalls reaching those speeds moved in and blew the Canopus off location. Shortly thereafter, Captain Roy Forsyth terminated diving operations. But when the 12-hour shift change occurred at midnight, weather conditions had calmed. Coming on duty, Supervisor Robert Kelly was instructed by diving superintendent Ed Hammond to continue with the dive program due to improved conditions.
The weather forecast now predicted that there would be a change in wind direction from west to north, and that conditions "would worsen later in the day" with wind speeds gusting to 35 knots. The Canopus was only a year old, and although it represented the latest and best technology of that era, the limits of her dynamic positioning system were 18–20 knots with the wind hitting her broadside.
Prior to the accident, the wind-speed indicator was fluctuating between 15 and 20 knots (28 and 37 km/h). Standing alongside the Beryl platform, near where the Canopus would be commencing work, was the Haakon Magnus, a Norwegian semi-submersible platform, with her massive anchor chains extended.[citation needed] Kelly determined the weather was suitable for diving and, at 0240, he launched the bell with Tony Prangley and Michael Ward inside.
At 0312, Ward locked out and found the pipe flange protruding from the wall of the platform base. Eight minutes later, Captain Forsyth called Kelly on the ship's intercom to alert him that a squall was approaching on the ship's radar. Kelly ordered Ward back to the bell where he sat for the next 40 minutes. At 0400 Ward was back on the job. Then, at 0545, the wind suddenly shifted directions and began blowing from the north at a speed of 40 knots, hitting the Canopus on her beam, and overpowering her dynamic positioning (DP) system. It was a sustained blow, the Contracts Manager would later testify:
When this wind arrived, it arrived really without any warning and it was not like a sudden gust of wind or a passing squall which then died down; it started blowing suddenly at 40 knots and remained at that level for a considerable period of time thereafter. It was a very strange occurrence, to say the least.