The Magellan 725 ROV(a deep ocean remotely operated vehicle, designed for high quality inspection and recovery operations. Using a fibre optic cable it can transmit high quality and speed video, sonar and data communications) was deployed onto the wreckage field identified by sonar, with the following objectives:
- Identify the wreckage as that of the Derbyshire.
- Document and identify primary sonar targets to determine how much of the wreck lies in the debris field and whether portions of the "bow" and "stern" could be identified in the debris field.
- Place a memorial plaque on the wreckage site.
- Search for further clues of the cause of the sinking.
The wreck of the mv Derbyshire was found and positively identified in June 1994 at a depth of 4,100m (2.5 miles). The distribution of the wreckage rules out break-up on impact with the sea bed. It is more likely that the break-up occurred at or near the surface with the release of the cargo of iron ore sand. The debris field measures about 1.3km from east to west, and it is thought unlikely, if not impossible, for wreckage to have tumbled and rolled such a distance once it had hit the seabed. Analysis of sonar records and video footage
The evidence does confirm that whatever happened to the Derbyshire, was sudden and catastrophic. The evidence also suggests that the damage done to the ship occurred at or near the surface and not upon hitting the sea bed. The presence of hundreds of relatively small pieces of wreckage on the seabed suggests an extremely violent break-up that must have occurred over a very short period of time, perhaps only seconds or minutes. Any other scenario would have permitted the crew to send out a distress message and would have also resulted in a much greater distribution of wreckage.
It has been measured by the US Navy that a sinking ship reaches a terminal velocity of about 22.2 feet per second, ie. about 15 mph. This would indicate that it would have taken about 10 minutes for the Derbyshire to reach the seabed. The hypothesis that the Derbyshire sank due to massive structural failure in the way of frame 65 is certainly strengthened by the evidence recovered on the ITF's expedition.
Clearly, what now needs to be determined is what sequence of events caused the Derbyshire to sink. What is now believed to have happened is that the inhabited section of the vessel, abaft frame 65, separated from the rest of the ship and sank almost immediately. The sonar evidence supports this, the research confirms frame 65 as a weak point, the sisterships all suffered cracking in this area, and the fact that no messages were ever sent by the crew gives this hypothesis added weight.
Following the discovery of the wreck of the Derbyshire, all available information was given to the Marine Accident Investigation Branch. In 1995 Dr. Brian Mawhinney MP asked Lord Donaldson to assess the situation including what further work was needed to learn more of and if possible, make a judgment about, the cause of the loss of the Derbyshire. On 5th December Lord Donaldson's report was published. He concluded that the only work which can be done at the present time involves a further more extensive, but final, examination of the site of the wreck of the DERBYSHIRE.
It is recommended therefore that the UK Government undertake a further expedition to gather more evidence, with the possible outcome of re-emphasis by the certification authorities on ensuring proper structural alignment during construction and repair activities. Further considerations into the implications of the use of Grade A Steel in bulk carriers having no specific toughness levels, and whether there is a correlation between the high failure rate of bulk carrier hull structures, and the relaxation of Classification Society rules which may have resulted in higher permissible stress levels in hull structures.
Epilogue
'Design may alter after Derbyshire wreck is tested'
Newspaper report dated Tuesday 5 December 1995
- BRITAIN is sending an expedition to examine the wreck of the bulk carrier Derbyshire, lost in the Pacific 15 years ago with 42 crew and two wives. Lord Donaldson, the former Master of the Rolls, said: "I am confident that such an expedition is likely to identify the cause of the loss, or so to narrow the possible causes of loss, that the maritime community will be compelled to look again at design standards." The decision is a victory for trade unions and survivors' families, who challenged the official inquiry's finding.
- The expedition, which will cost £2 million, is being part funded through the European Commission. It will send a Remote Operated Vehicle (ROV) to depths of two-and-a-half miles.' Cameras will record objects and map their position. The Government is inviting bids for the contract and hopes that the work can begin in the spring.
3rd June 1996. Lord Goschen, Shipping Minister, announced the expedition to re-examine the wreck of the Derbyshire would take place in 2 phases. Phase 1 was a limited sonar and photographic survey of the wreckage field and ws carried out in July 1996. The stern was found and the bow was revisited; the quality of the photographs was disappointing.
Phase 2 is planned for 3rd March 1997, lasting about 47 days and including a photo-mosaic of the area. As it takes three months to develop the final pictures, phase 2 will start without an overall plan of the wreckage site - again disappointing. In fact the final pictures will not be available until after the end of phase 2.
It is the hope of all the members of the DFA that the cause of the loss of the Derbyshire will be discovered, and that data found during this expedition will help to improve the safety record of bulk carriers worldwide.
We also hope that families of any future maritime disasters, never have to wait as long as members of the DFA have waited to discover the causes of the loss. 16 years is too long; there should have been an immediate public inquiry into all shipping disasters.
Let us hope that those who died on the Derbyshire, and other bulk carriers, can at last rest in peace, and their families feel that justice has finally been done.
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