| Career (United Kingdom) | |
|---|---|
| Name: | Liverpool Bridge (1975-78) Derbyshire (1978-80) |
| Owner: | Bibby Line |
| Port of registry: | Liverpool |
| Builder: | Swan Hunter, Teeside, United Kingdom |
| Yard number: | 57[1] |
| Launched: | 5 December 1975[1] |
| Completed: | June 1976[1] |
| Homeport: | Liverpool |
| Identification: | IMO Number 7343805 |
| Fate: | Lost in Typhoon Orchid, 1980 |
| Notes: | Largest British ship ever lost at sea |
| General characteristics | |
| Tonnage: | 91,655 gross 67,429 net 169,044 deadweight[1] |
| Length: | 294.20 m (965 ft 3 in) |
| Beam: | 44.30 m (145 ft 4 in) |
| Speed: | 15.5 knots (28.7 km/h) |
| Capacity: | approx. 160,000 tonnes of cargo |
| Complement: | 42 |
The MV Derbyshire was an ore-bulk-oil combination carrier built in 1976 by Swan Hunter, as the last in the series of the Bridge-class sextet. She was registered at Liverpool and owned by Bibby Line.
She was lost September 9, 1980 during Typhoon Orchid, south of Japan (); all hands (42 crew and two wives) were lost. At 91,655 gross tons she was, and remains, the largest UK ship (more than three times the size of the Titanic) ever to have been lost at sea.
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Full investigation of the cause and details of the accident was long delayed. Persistent refusal by the UK government to mount an inquiry prompted the International Transport Workers' Federation to launch its own search for the wreck. The search, led by American shipwreck hunter David Mearns, was declared hopeless by a major marine consultancy, but the union persisted even though they could only afford eight days of search. The wreck was found by Mearns' team in June 1994 when the eight-day period was almost up. The survey managed to deploy a remotely operated vehicle, the Magellan, to take preliminary photos, which confirmed the finding. The strange orientation of the wreck was published in a report on March 12, 1998. This prompted the British Government to reopen a formal investigation into the sinking.
The formal investigation commenced on April 2, 2000. It eventually concluded that the ship sank because of structural failure and absolved the crew of any responsibility in the sinking.
Evidence from the underwater surveys showed that the closing appliances for nine ventilator openings in the bow section of the ship were missing; it was concluded that this had allowed seawater to flood into the ship and cause it to trim down by the bow. This adverse forward trim enabled storm force waves to batter the foremost cargo hold hatch covers causing them to collapse and the forward cargo hold to then flood with sea water. The same process was repeated on the number two and number three cargo holds. The additional weight of seawater, coupled with the heavy seas during Typhoon Orchid, caused the main hull to suffer a catastrophic structural collapse and the vessel to founder.
The 1986 grounding of the similar MV Kowloon Bridge also resulted in its breakup, and faults found in two other sister ships lent weight to an earlier hypothesis of structural failure at a known structural discontinuity, at frame 65, just forward of the ship's main pump room. However, the findings from the 2000 formal investigation, which blamed deficiencies in the strength of the hatch covers, effectively ruled out this earlier hypothesis.
The Derbyshire Family Association was awarded the Marine Society's Thomas Gray Silver Medal in July 2004 for campaigning for better safety regulations regarding bulk carriers.
Rumours of crew negligence circulated in the marine industry early in the investigation were based on the leaked unfinished findings of the assessors appointed by Lord Donaldson of Lymington on behalf of the British Department of Transport. These rumours were not substantiated by the investigation. They examined the 135,774 pictures of the Derbyshire wreck taken during two surveys by a research vessel of the Woods Hole Oceanographic Institution. These assessors, Robin Williams and Remo Torchio, both naval architects, concluded that amongst other obvious openings for water ingress, including broken ventilators, a mooring rope coming out of a relatively undamaged and unlatched fore deck access hatch led to the possibility that over several hours the vessel took on water in the storm to a degree that produced a marked bow down trim coupled with large waves crashing onto the first hatch cover and its eventual failure. The vessel then began to take on more water and sank very quickly.
The third assessor, Douglas Faulkner, Professor of Marine Architecture and Ocean Engineering at the University of Glasgow, departed the investigation before the stories of crew negligence circulated. In 2001, Prof. Faulkner published a lengthy and highly analytical paper examining the Derbyshire's loss in light of the emerging body of scientific evidence regarding the mechanics of freak waves. Among other things, it is now becoming more widely accepted in the scientific community that such rogue waves are far more common than previous mathematical models (and the older shipbuilding standards that stemmed from them) had suggested. Prof. Faulkner's paper won the Royal Institution of Naval Architects's (RINA) award for excellence that year. Prof. Faulkner took direct issue with the conclusions of the original assessment, noting that given the meteorological conditions, and the length of time she was exposed to the peak conditions of the storm, it was almost certain that Derbyshire would have encountered a wave of sufficient size to destroy her. He concluded: "Beyond any reasonable doubt, the direct cause of the loss of the M.V. Derbyshire was the quite inadequate strength of her cargo hatch covers to withstand the forces of Typhoon Orchid." This conclusion has potentially dire implication for many earlier-generation bulk carriers, as they were all built to loading standards considered safe before the mechanics of these giant waves were understood.
In November 1997 the International Maritime Organization (IMO) adopted new rules covering survivability and structural requirements for bulk carriers of 150 metres and upwards. The bulkhead and double bottom must be strong enough to allow the ship to survive flooding in hold 1 unless loading is restricted. It also adopted revised guidelines on ship surveys and a code of practice for safer loading and unloading. [2]