Byford Dolphin#Diving bell accident

{{Multiple issues|

{{Cleanup|reason=inconsistent ports of registry|date=March 2022}}

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{{Infobox ship begin

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{{Infobox ship image

| Ship image = ByfordDolphinAtInvergordon2008.jpg

| Ship caption = Byford Dolphin in dry dock at Invergordon, Scotland, in 2008

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{{Infobox ship career

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| Ship name = {{unbulleted list | Byford Dolphin | Deep Sea Driller (1974–1978)}}

| Ship owner = Byford Dolphin Pte. Ltd. (Fred. Olsen Energy)

| Ship operator = Dolphin Drilling

| Ship registry = {{unbulleted list | {{SIN}} | {{PAN}} (1974–2005)}}

| Ship route =

| Ship ordered =

| Ship builder = Aker Group

| Ship original cost =

| Ship yard number = Aker Verdal A/S (695)

| Ship way number =

| Ship laid down = 31 October 1972

| Ship launched =

| Ship completed = 1 February 1974

| Ship christened =

| Ship acquired =

| Ship maiden voyage =

| Ship in service =

| Ship out of service = Laidup 2016

| Ship identification = {{unbulleted list | Call sign: 9VDG7 | DNV ID: 09092 | {{IMO Number|8750584}} | MMSI no.: 563601000}}

| Ship fate = Beached Aliağa and scrapped 2019

| Ship notes =

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{{Infobox ship characteristics

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| Header caption =

| Ship class = DNV class: 1A1 Column-stabilised Drilling Unit UKVS

| Ship tonnage = {{unbulleted list | {{GT|11,792}} | {{GT|3,538}} }}

| Ship displacement =

| Ship length = {{convert|108.2|m|abbr=on}}

| Ship beam = {{convert|67.4|m|abbr=on}}

| Ship draught =

| Ship depth = {{convert|36.6|m|abbr=on}}

| Ship decks =

| Ship deck clearance =

| Ship ramps =

| Ship ice class =

| Ship sail plan =

| Ship power =

| Ship propulsion =

| Ship speed = {{cvt|4.5|kn|km/h}}

| Ship capacity = {{unbulleted list | Variable Deck Lo: 3,021 t | Liquid Mud: 3,981 bbls (534 m³) | Bulk Mud/Cement: 547 t / 270 t}}

| Ship crew = 102 berths

| Ship notes = {{cite web |title=Byford Dolphin |url=http://www.fredolsen-energy.no/?aid=9048931 |publisher=Fred.Olsen Energy ASA |date=24 February 2008 |access-date=14 July 2010}}

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Byford Dolphin was a semi-submersible, column-stabilised drilling rig operated by Dolphin Drilling, a subsidiary of Fred Olsen Energy. Byford Dolphin was registered in Hamilton, Bermuda,{{cite ship register |register=DNV |id=09092 |shipname=Byford Dolphin |access-date=14 July 2010 }}{{dead link|date=March 2022}} and drilled seasonally for various companies in the British, Danish, and Norwegian sectors of the North Sea. In 2019, Dolphin scrapped the rig.{{Cite web |last=Dykes |first=Andrew |date=2023-11-04 |title=Byford Dolphin diving incident casts long shadow 40 years on |url=https://www.energyvoice.com/oilandgas/norway/540650/byford-dolphin-diving-incident-casts-long-shadow-40-years-on/ |access-date=2024-06-06 |website=Energy Voice |language=en-US}}

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 critically injuring another dive tender.{{cite journal |vauthors=Giertsen JC, Sandstad E, Morild I, Bang G, Bjersand AJ, Eidsvik S |title=An explosive decompression accident |journal=The American Journal of Forensic Medicine and Pathology |volume=9 |issue=2 |pages=94–101 |date=June 1988 |pmid=3381801 |doi=10.1097/00000433-198806000-00002 |s2cid=41095645}}

Description

Built as Deep Sea Driller, Byford Dolphin 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.{{Cite web |title=Rig Data: Byford Dolphin |publisher=Rigzone |url=http://www.rigzone.com/data/rig_detail.asp?rig_id=102 |access-date=2010-05-23 |archive-url=https://web.archive.org/web/20110607125608/http://www.rigzone.com/data/rig_detail.asp?rig_id=102 |archive-date=7 June 2011 |url-status=dead}}

Byford Dolphin had an overall length of {{convert|108.2|m}}, breadth of {{convert|67.4|m}} and depth of {{convert|36.6|m}}. It had a maximum drilling depth of {{convert|6.1|km|mi}}, and it could operate at a water depth of {{convert|460|m|-2}}.{{Cite web |title=Byford Dolphin |publisher=Fred. Olsen Energy |url=http://www.fredolsen-energy.no/arch/_img/9073113.pdf |access-date=2010-05-23 |url-status=dead |archive-url=https://web.archive.org/web/20110720154005/http://www.fredolsen-energy.no/arch/_img/9073113.pdf |archive-date=20 July 2011}} 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 manoeuvre with its own engines (to counter drift and ocean currents), but for long-distance relocation it had to be moved by specialized tugboats.

class="wikitable"

|+ Byford Dolphin specifications

Operating deck load

|3,025 tonne

Crew quarters

|102 persons

Operating water depth

|{{convert|460|m

2}} maximum

Derrick

|{{cvt|49|m

1}} Shaffer top compensator

Mooring system

|12-point

Blow-out preventer

|Hydril {{cvt|476|mm}}, {{cvt|10000|kPa}}

Sub Sea Handling System

|Christmas tree

Deck cranes

|2 × 40 tonnes

Incidents and accidents

= Byford Dolphin accident of 1983 =

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), 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.

File:Byford Dolphin Accident.jpg

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 a mechanical failure caused the clamp that was keeping the trunk sealed to open before Hellevik (diver 4) had closed the door to the chamber. This resulted in both chambers being rapidly depressurized 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.{{rp|94}}{{cite book |title=North Sea Divers - a Requiem |last=Limbrick |first=Jim |pages=168–170 |location=Hertford |publisher=Authors OnLine |year=2001 |isbn=0-7552-0036-5 |url=https://books.google.com/books?id=lPp68NAoUF0C&pg=PA168 |via=Google Books}}

== 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.{{rp|97, 101}} This fat was unlikely to be embolic, but must have precipitated from the blood in situ.{{rp|101}} The postmortem suggested that bubble formation in the blood denatured the lipoprotein complexes, rendering the lipids insoluble.{{rp|101}} These now-insoluble lipids are likely what stopped their circulation.{{rp|101}} The fourth diver died instantly from gross dismemberment when the blast forced his body out through the partially blocked doorway.{{rp|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 {{convert|60|cm}} long created by the jammed interior trunk door. With the escaping air and pressure, gross dismemberment ensued; 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 from the bell, with one section being found {{convert|10|m|4=-1}} vertically above the exterior pressure door.{{rp|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 centre 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 {{convert|24|in|cm|-1|order=flip}} 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 megaphone 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 may also have taken its toll on the crew, who had been working for longer than 12 hours.

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.

{{cite report

|title=Dykkerulykken på Byford Dolphin 5 november 1983 : rapport fra ekspertkommisjonen

|trans-title=The Diving Accident at Buford Dolphin on 5 November 1983: Report of the Expert Commission

|date=1984

|work=Norges Offentlige Utredninger

|trans-work=Norwegian Public Reports

|publisher=Universitetsforlaget

|publication-place=Oslo

|isbn=9788200708896

|oclc=470294994

|language=nb

|id=NOU 1984:11

|via=Nasjonalbiblioteket, Norway

|url=https://urn.nb.no/URN:NBN:no-nb_digibok_2013081906099

}} 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",{{cite book |title=Rules for certification of diving systems, 1982 |year=1982 |publisher=Det Norske Veritas |chapter=Sec 3 B305 |language=en |oclc=9287902}} 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.{{citation needed|date=November 2017}}

Among others, former crew members of Byford Dolphin and NOPEF (a Norwegian oil and petro-chemical union) 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 (which would be impossible to open while the chamber system was still under pressure), outboard pressure gauges, and a safe communication system, all of which had been held back because of dispensations by the Norwegian Petroleum Directorate.{{cite news |url=http://www.dagbladet.no/tekstarkiv/artikkel.php?id=5001080047056&tag=item&words=byford%3Bdolphin |title=Historiens verste dykkerulykke |trans-title=History's worst diving accident |last=Ringheim |first=Gunnar |date=22 March 2008 |publisher=Dagbladet.no |location=Oslo |language=no |access-date=2009-11-18 |archive-url=https://web.archive.org/web/20110605103112/http://www.dagbladet.no/tekstarkiv/artikkel.php?id=5001080047056&tag=item&words=byford%3Bdolphin |archive-date=5 June 2011 |url-status=dead}}

== 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."{{cite news |last=Lister |first=David |title=Families of British divers killed in North Sea oil boom sue Norway |url=http://www.timesonline.co.uk/tol/news/world/europe/article3613778.ece |newspaper=The Times |access-date=2009-11-18 |location=London |date=2008-03-25}}{{dead link|date=September 2024|bot=medic}}{{cbignore|bot=medic}} The families of the divers eventually received compensation for the damages from the Norwegian government, 26 years after the incident.{{cite web |author=((Staff writers)) |url=http://cdiver.net/news/norwegian-government-finally-pays-out-for-1983-byford-dolphin-diver-death/#more-3678 |title=Norwegian government finally pays out for 1983 Byford Dolphin diver death |work=cDiver |date=20 October 2009 |access-date=14 July 2010}}

= 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 US dollars in lost income.