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 ever to have been lost at sea.
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 after 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. They eventually concluded that the ship sank because of structural failure and absolved the crew of any responsibility in the sinking. Twelve ventilation holes were found to be responsible for allowing water to get into the ship, flooding it, and pulling it down by the bow. This submerged portions of the deck, and caused the foremost cargo bay doors to be underwater. The pressure crushed them, flooding the chamber. This repeated several times. Coupled with the rough waves bobbing the ship, this resulted in the ship experiencing greater stresses than it was designed for. The 1986 grounding of the similar MV Kowloon Bridge resulted in its break up, and faults found in two other sister ships lend weight to this conclusion.
Earlier stories of crew negligence were based on the deduction of two of the three assessors appointed by Lord Donaldson of Lymington on behalf of the British Department of Transport. 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 but lacking any seafaring experience, concluded that a mooring rope coming out of a fore access hatch was evidence that the crew was busy preparing the arrival of the vessel and left the access hatch open with the rope half out when the typhoon was approaching. But on all ships worldwide this operation takes place only a few hours before arrival and not two days out at sea as it was then the case. During the re-opened formal investigation of April/July 2000 it was easy to prove that the access hatch had been forced open by a heavy impact, probably the broken winch or fore mast, and due to its buoyancy the rope floated half way out.
The third assessor was Douglas Faulkner, Professor of Marine Architecture and Ocean Engineering at the University of Glasgow. He resigned before that allegation of crew negligence had been drafted.
In 2001, Prof. Douglas Faulkner, Emeritus Professor of Naval architecture, University of Glasgow, 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' 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.