Byford Dolphin drilling rig is an Enhanced Aker H-3 design which was built by Aker Group at the Aker Verdal shipyard in 1974. Between 1974 and 1978, it was named Deep Sea Driller. Byford Dolphin has a length of, breadth of and depth of. It has a maximum drilling depth of, and it could operate at a water depth of. As a drilling rig, Byford Dolphin is equipped with advanced drilling equipment and has to meet strict levels of certification under Norwegian law. Byford Dolphin is able to maneuver with its own engines, but for long-distance relocation, it must be moved by specialist tugboats.
Operating deck load
3,025 tonne
Crew quarters
102 persons
Operating water depth
maximum
Derrick
Shaffer top compensator
Mooring system
12-point
Blow-out preventer
Hydril,
Sub Sea Handling System
Christmas tree
Deck cranes
2 × 40 tonnes
Accidents and incidents
''Deep Sea Driller'' accident
On 1 March 1976, the rig ran aground during transit from a block in the North Sea to Bergen. All crew were evacuated in the life boats, but six people died when they fell from their life boat.
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 to a diving bell. The divers were Edwin Arthur Coward, Roy P. Lucas, Bjørn Giæver Bergersen and Truls Hellevik. They were assisted by two dive tenders, William Brown Crammond and Martin Andrew Saunders. Hellevik was about to close the door between the chamber system and the trunk when the chamber explosively decompressed from a pressure of nine atmospheres to one atmosphere. One of the tenders, 32-year-old William Crammond of Great Britain, and all four of the divers were killed instantly; the other tender, Saunders, was severely injured. Just prior to the event, decompression chambers 1 and 2 were connected via a trunk to a diving bell. This connection was sealed by a clamp operated by Crammond and Saunders, who were experienced divers. A third chamber was connected to this system but was not involved. Coward and Lucas were resting in chamber 2 at a pressure of 9 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 bell door.
The diving supervisor would then slightly increase the bell pressure to seal this door tightly.
Open the clamp to separate the bell from the chamber system.
The first two steps had been completed when, for an unknown reason, Crammond opened the clamp before Diver 4 could close the door to the chamber. This resulted in the explosive decompression of the unsealed chamber. Air rushed out of the chamber with tremendous force, jamming the interior trunk door and pushing the bell away, striking the two tenders. Crammond was killed while Saunders was severely injured.
Medical findings
Medical investigations were carried out on the remains of the four divers and of one of the tenders. 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. This fat was unlikely to be embolic, but must have precipitated from the blood in situ. The autopsy suggested that rapid bubble formation in the blood denatured the lipoprotein complexes, rendering the lipids insoluble. The blood of the three divers left intact inside the chambers likely boiled instantly, stopping their circulation. The fourth diver was dismembered and mutilated by the blast forcing him out through the partially blocked doorway and would have died instantly. 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 long created by the jammed interior trunk door. With the escaping air and pressure, it included bisection of his thoracoabdominal cavity, which resulted in 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 vertically above the exterior pressure door.
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, 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 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 Byford Dolphin and NOPEF have come forward and claimed the investigation was a cover-up. They claimed that the commission investigating the accident did not mention in their report the irresponsible dispensations on vital equipment requested by Comex and authorized by the diving section to the Norwegian Petroleum Directorate, which played a vital role in the accident's occurrence. They also alleged the accident was due to a lack of proper equipment, including clamping mechanisms equipped with interlocking mechanisms, outboard pressure gauges, and a safe communication system, all of which had been held back because of dispensations by the Norwegian Petroleum Directorate.
Post-investigation
The conclusions of the investigation were disputed, and a group of divers gathered evidence with the intention to "find justice for all of the crew of Byford Dolphin." The group formed the North Sea Divers Alliance in the early 1990s and since then has campaigned for compensation for divers killed or injured in the Norwegian Sector of the North Sea.
Lawsuit
The North Sea Divers Alliance, formed by early North Sea divers and the relatives of those killed, continued to press for further investigation and, in February 2008, obtained a report that indicated the real cause was faulty equipment. Clare Lucas, daughter of Roy Lucas, said: "I would go so far as to say that the Norwegian Government murdered my father because they knew that they were diving with an unsafe decompression chamber." The families of the divers eventually received compensation for the damages from the Norwegian government 26 years after the incident.
Other incidents
On 17 April 2002, a 44-year-old Norwegian worker on the rig was struck on the head and killed in an industrial accident. The accident resulted in Byford Dolphin losing an exploration contract with Statoil, which expressed concerns with the rig's operating procedures. The incident cost the company millions of dollars in lost income.
