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Christopher Byford Biography & Facts

Byford Dolphin was a semi-submersible, column-stabilised drilling rig operated by Dolphin Drilling, a Fred Olsen Energy subsidiary. It drilled seasonally for various companies in the British, Danish, and Norwegian sectors of the North Sea. It was registered in Hamilton, Bermuda. In 2019, Dolphin scrapped the rig. The rig was the site of several serious incidents, most notably an explosive decompression in 1983 that killed four divers and one dive tender, as well as badly injuring another dive tender. Description Built as Deep Sea Driller, it was the first-of-class in the highly successful Aker H-3 series, designed by Aker Group and completed at the Aker Verdal shipyard in 1974. Byford Dolphin had an overall length of 108.2 metres (355 ft), breadth of 67.4 metres (221 ft) and depth of 36.6 metres (120 ft). It had a maximum drilling depth of 61 kilometres (61,000 m), and it could operate at a water depth of 460 metres (1,500 ft). As a drilling rig, Byford Dolphin was equipped with advanced drilling equipment and originally met strict levels of certification under Norwegian law, though in later years it was banned from Norwegian waters. Byford Dolphin was able to maneuver with its own engines (to counter drift and ocean currents), but for long-distance relocation it had to be moved by specialized tugboats. Accidents and incidents Deep Sea Driller accident On March 1, 1976, the rig ran aground during transit from a block in the North Sea to Bergen. All crew were evacuated, but six people died when they fell out of their boats. Diving bell accident On Saturday, 5 November 1983, at 4:00 a.m., while drilling in the Frigg gas field in the Norwegian sector of the North Sea, four divers were in a diving chamber system on the rig's deck that was connected by a trunk (a short passage) to a diving bell. The divers were Edwin Arthur Coward (British, 35 years old), Roy P. Lucas (British, 38), Bjørn Giæver Bergersen (Norwegian, 29) and Truls Hellevik (Norwegian, 34). They were assisted by two dive tenders, William Crammond (British, 32) and Martin Saunders. At the time of the accident, decompression chambers 1 and 2 (along with a third chamber which was not in use at the time) were connected via a trunk to a diving bell. The connection made by the trunk was kept sealed by a clamp operated by Crammond and Saunders, who were experienced divers. Coward and Lucas were resting in chamber 2 at a pressure of 9 atmospheres (atm). The diving bell with Bergersen and Hellevik had just been winched up after a dive and joined to the trunk. Leaving their wet equipment in the trunk, the two divers climbed through the trunk into chamber 1. The normal procedure would have been: Close the diving bell door, which would have been open to the trunk. Slightly increase the pressure in the diving bell to seal the bell door tightly. Close the chamber 1 door, which was also open to the trunk. Slowly depressurize the trunk until it reached a pressure of 1 atm. Open the clamp to separate the diving bell from the chamber system. The first two steps had been completed when Crammond mistakenly opened the clamp that was keeping the trunk sealed before Hellevik (diver 4) had closed the door to the chamber. This resulted in both chambers being instantly decompressed from 9 atmospheres to the ambient external pressure of 1 atm. Air rushed out of the chamber system with tremendous force, jamming the interior trunk door and pushing the bell away, striking the two tenders. All four divers were killed; one of the tenders, Crammond, was killed, while Saunders was severely injured.: 94  Medical findings Medical investigations were carried out on the remains of the four divers. The most notable finding was the presence of large amounts of fat in large arteries and veins and in the cardiac chambers, as well as intravascular fat in organs, especially the liver.: 97, 101  This fat was unlikely to be embolic, but must have precipitated from the blood in situ.: 101  The autopsy suggested that bubble formation in the blood denatured the lipoprotein complexes, rendering the lipids insoluble.: 101  These now-insoluble lipids are likely what stopped their circulation.: 101  The fourth diver died instantly from gross dismemberment when the blast forced his body out through the partially blocked doorway.: 95, 100–101  Coward, Lucas, and Bergersen were exposed to the effects of explosive decompression and died in the positions indicated by the diagram. Investigation by forensic pathologists determined that Hellevik, being exposed to the highest pressure gradient and in the process of moving to secure the inner door, was forced through the crescent-shaped opening measuring 60 centimetres (24 in) long created by the jammed interior trunk door. With the escaping air and pressure, it included bisection of his thoracoabdominal cavity, which resulted in fragmentation of his body, followed by expulsion of all of the internal organs of his chest and abdomen, except the trachea and a section of small intestine, and of the thoracic spine. These were projected some distance, one section being found 10 metres (30 ft) vertically above the exterior pressure door.: 95  Investigation The committee investigating the accident concluded that it was caused by human error on the part of the dive tender who opened the clamp. The trunk door had a center hinge design, similar to a butterfly valve disc, and the door was rotated too far to the left, causing the rim of the interior hatch to lodge on the door opening. This left a crescent-shaped opening, similar to a manhole cover left ajar but held in place. This created an opening that was 24 inches (61 cm) across horizontally. It is not clear whether the tender who opened the clamp before the trunk was depressurized did so by order of his supervisor, on his own initiative, or because of miscommunication. At the time, the only communication the tenders on the outside of the chamber system had was through a bullhorn attached to the wall surface; with heavy noise from the rig and sea, it was hard to listen in on what was going on. Fatigue from many hard hours of work also took its toll among the divers, who often worked 16-hour shifts. This incident was also attributed to engineering failure. The obsolete Byford Dolphin diving system, dating from 1975, was not equipped with fail-safe hatches, outboard pressure gauges, and an interlocking mechanism, which would have prevented the trunk from being opened while the system was under pressure. Prior to the accident, Norske Veritas had issued the following rule for certification: "Connecting mechanisms between bell and chambers are to be so arranged that they cannot be operated when the trunk is pressurized", therefore requiring such systems to have fail-safe seals and interlocking mechanisms. One month after the accident, Norske Veritas and the Norwegian oil directorate made the rule final for all bell systems. Among others, former crew members of Byfor.... Discover the Christopher Byford popular books. Find the top 100 most popular Christopher Byford books.