FOR 60 years the people of Sheerness in the UK have been living next to a time bomb. A lethal mixture of unstable second world war bombs – amounting to 1400 tonnes of TNT – is in the rusting wreck of the Richard Montgomery, a US cargo ship which lies half submerged on a sandbank in the Thames estuary, just over 2 kilometres from the Kent town.
If the cargo explodes, the blast will bring death and devastation to a wide area. The UK government, though, has always played down the risk. Only seven months ago David Jamieson, the UK transport minister responsible for shipping, said that the Richard Montgomery “appears to be in a stable condition”. But 60 years after it sank, a żěè¶ĚĘÓƵ investigation, based partly on recently released government documents, reveals that the cargo is still deadly. A collision with another vessel, a terrorist or even the small shock of a bomb moving in the tide could set off the explosives. Worse, far from being stable, the condition of the bombs means they could even explode spontaneously.
Finding a solution to the problem is becoming more and more urgent. There is a worrying crack in the hull of the ship, close to where the most sensitive bombs are lying. If the hull gives way bombs could scatter onto the seabed, or the whole lot could go up. And a new natural gas terminal designed to supply 5 per cent of the UK’s gas is scheduled to open next year only 2.5 kilometres from the wreck. Soon, ships carrying 145,000 cubic metres of liquefied natural gas at a time will be passing along a newly dredged channel just a couple of hundred metres from the Richard Montgomery.
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In 1999 a risk assessment was commissioned by the government’s Receiver of Wreck – who is responsible for all wrecks in the country’s waters, including that of the Richard Montgomery. Sources familiar with the contents of the report say that it outlines five options for dealing with the ship, and analyses the risks attached to each. In 2001, at a meeting organised to discuss the report and the future of the wreck, a consensus emerged that it was time to act.
Yet nothing has happened. The risk assessment has not even been published. It has spent the past three years lying on the desks of civil servants in the Department for Transport’s shipping policy division, gathering dust in the “too difficult” tray. Sophia Exelby, the current Receiver of Wreck, says that the report is being studied by the department. “But there are cost implications, and they have to think long and hard about what they are going to do,” she says.
So how has the Richard Montgomery been allowed to become such a threat to people and property? Recently declassified documents reveal that the government’s reluctance to face the expense of dealing with the wreck is a thread that runs through 60 years of grappling with the problem. It is the reason why the ship was left there in the first place, and it is the reason for the delay now.
The USS Richard Montgomery was one of 2700 “Liberty” cargo ships built during the second world war. Launched in 1943, it arrived in the Thames estuary on 20 August 1944 laden with a cargo of bombs to help the Allied push in France following the D-Day landings.
Unfortunately the ship was directed to a berth that was too shallow and it ran aground. The UK government’s initial concern was to salvage the bombs for the war effort. Fifty-two stevedores were hired to unload the cargo, partly in the hope that the ship, once lightened, could be refloated.
It was a vain hope. The ship stuck fast in the soft mud and started to break up. Its back finally broke on 8 September, leaving it in two halves. Salvage work stopped a fortnight later. By this time the rear half of the ship had been completely cleared, but two holds at the front had barely been touched, leaving 13,700 explosive devices, including general purpose, semi-armour-piercing and fragmentation bombs.
It is clear from files at The National Archives that cost was the reason the Admiralty, the government department in charge of the navy, halted the work. The stevedores were paid danger money, and on 27 September an Admiralty official complained about the cost to the Port of London Authority, which was organising the salvage on behalf of the Admiralty. “It is obvious that these rates are excessively high and we consider also that the rate of discharge is exceedingly slow and most unsatisfactory.” The PLA rejected this, saying it was not slow considering the circumstances.
By November 1944 the government had decided that it was best to do nothing about the problem, as salvage could cost £90,000. “The cost of removing this wreck would far exceed its value,” wrote Robert Brooks, the Admiralty’s head of salvage. In 1946 bomb-disposal experts at the Ministry of Defence added reassuringly that the bombs “would not be likely to constitute a danger if they are unfuzed (sic), provided that no big explosion takes place in close proximity to them”.
The assumption that the bombs lacked fuses could not have been more wrong. Most, if not all, of the 2600 fragmentation bombs are fused, although documents show that the government did not seem to appreciate this until the early 1950s.
The bombs themselves have watertight cases and most experts agree that the TNT they contain is probably in first-class condition. The fuses, however, fall well short of this state, a fact that the government has known since 1967. The fuses contain lead azide, a chemical designed to explode on impact and detonate the main charge of TNT. Although the bombs are watertight, the fuses are not. This isn’t a problem if seawater gets in: it will wash out the lead azide. But there is a nightmare scenario – and it only has to apply to one fused bomb.
If water vapour, and not water, gets into the fuse it will react with the lead azide to form hydrazoic acid. This in turn will attack the detonating cap, which is 95 per cent copper, to form copper azide, which is highly sensitive and will explode at the slightest knock. It is so sensitive that it cannot be used commercially. One fuse detonating one fragmentation bomb could easily set off the rest of the cargo.
This realisation gave the government a new reason for doing nothing – the bombs were too unstable to move. In 1967 an official from the government’s Explosives Research and Development Establishment (ERDE) said, “I consider that the risk of very sensitive azides being present in this ammunition is still real.”
In public the government played down the danger. When a local member of parliament started asking questions in the late 1960s, civil servants at the Ministry of Defence came up with a classic evasion: “There is no known reason why the chance of explosion should be greater now than during the last 20 years.” Even today the government’s public position is that there is no cause for alarm. “The majority of the munitions are unfused,” Jamieson said seven months ago. “The munitions which are fused are considered by experts to be likely to be stable given the circumstances and duration of storage.” But this claim cannot easily be squared with the evidence. Widening cracks in the ship’s hull, for example, could cause a fatal movement of the cargo.
Alarming cracks
The Maritime and Coastguard Agency carries out regular surveys of the wreck, looking for signs of rusting or worsening cracks. Divers inspect the wreck almost every year, sonar surveys are carried out about every 10 years or so and last year metallurgists examined samples from the hull to check for rust. In May this year, in an uncanny echo of the government’s stance in the 1960s, the MCA said that its latest survey shows “there are no grounds for increased alarm”.
But these surveys reveal the growth of a crack by number 2 hold, where many of the bombs are situated (see Diagram). Exelby says this crack is one of her main concerns. In 1965 when it was first measured, the crack was 12 millimetres wide at deck level and 3 metres long. By 1981 the crack was 5 centimetres wide and 6 metres long. Last year the crack was 17 centimetres wide.
The number 2 hold is just about the most sensitive part of the wreck. A 1972 analysis by David Cotgrove, a former government weapons scientist, of the ship’s cargo manifest and of the original salvage report shows that more than 90 per cent of the remaining fragmentation bombs are in this hold, just below the deck, where the crack is widest.
There are other risks. Michael Fellows, an ex-Royal Navy expert in the disposal of submerged explosives, says that a spontaneous explosion of unfused bombs could be the biggest danger. During the war, ammonium nitrate was often added to TNT used in bombs. Copper and iron in the bomb casings mean electrolytic corrosion is likely, and if water gets in, wet ammonium nitrate can react explosively with iron. It is for this reason that charts of the Beaufort Dyke, the munitions dump in the Irish Sea, used to warn mariners that “underwater explosions are liable to occur in the dumping grounds”.
Over the years fishing vessels in the Thames estuary have pulled up an unknown number of stray bombs in their trawls. Until the 1970s, when the government began to pay a bounty for recovered bombs, trawlers would sometimes dump them around the Richard Montgomery, adding to the potential hazard and making it more unpredictable.
The wreck could also be rammed by another vessel going off course – a risk that is heightened by planned increases in passenger, cargo and natural-gas carrier vessels along the river Thames and the river Medway. There is an exclusion zone of a couple of hundred metres around the wreck, and Medway Ports, the company that owns the port at Sheerness, keeps a radar watch. But this is unlikely to put off a determined terrorist.
If the wreck does explode it will be one of the biggest non-nuclear explosions ever: 700 times the size of the 1995 Oklahoma City bomb. Even so, the government has consistently played down the effects of an explosion. “The wreck has become something of a journalistic legend in north Kent, which is revived at not infrequent intervals during quiet news periods,” the navy’s public relations man wrote in 1964. “It is popularly believed that much of Sheerness would be destroyed if the wreck exploded.”
Just how much damage an explosion would cause depends on the tides: the more water covering the wreck, the greater the damping effect. The worst case would be an explosion of the wreck’s cargo at low tide, when barely 11 metres of water covers it. In 1970 the ERDE carried out tests on scale models and made a series of calculations from known explosions.
They calculated that the blast would shatter almost every window in Sheerness and send a 300-metre-diameter column of water, mud, metal and munitions almost 3 kilometres up in the air. It would also create a wave. This would only be about 30 centimetres high by the time it reaches Sheerness, and would scarcely trouble the town’s impressive sea defences. However, out in the estuary the wave could easily rise to five metres high, enough to sink many small craft. The shock of the blast, transmitted through the estuary clay, would cause structural damage to buildings as far as 3 kilometres inland from Sheerness.
The ERDE made no assessment of the consequent injuries or loss of life. Cropping up frequently in government papers, however, are concerns over the effect that an explosion might have on the oil refineries 3 kilometres away on the Isle of Grain – which is to be the site of the new gas terminal. These concerns were not aired in public, and one document from civil servants to ministers stated: “It does not seem to be prudent to quote the estimated damage an explosion would cause.”
The ERDE based part of its calculations on a test explosion carried out by Canadian defence researchers at Suffield in Alberta. żěè¶ĚĘÓƵ asked John Slater, of Defence Research and Development Canada in Suffield to check the calculations in the light of current knowledge. Slater’s results were remarkably similar. He calculates that the peak air blast will be slightly lower and the height of the column of ejected material will be slightly more than 3 kilometres. Even if only some of the cargo detonated, one of the biggest hazards would be from unexploded bombs thrown out across the area, says Slater.
Two years after the government commissioned the risk assessment in 1999, the Maritime and Coastguard Agency convened a meeting to discuss the long-term future of the wreck. The meeting was attended by local authorities and the two port authorities concerned with navigation in the area. They came to the conclusion that doing nothing was not an option for much longer.
Act now
The 1999 report outlines five options for dealing with the wreck, and analyses the risks attached to each. At one end of the spectrum is continuing the strategy of the past 60 years, that is, doing nothing. Two options involve burial of the wreck, either in sand or concrete. The most elaborate plan is to build a protective sand bank and ditch around the wreck, much like an iron-age earthwork, to deaden any blast. The cargo would then be removed in parts or in one operation. In both these scenarios the explosives would have to be lifted by crane and towed away underwater for disposal, and would require the evacuation of the entire population of Sheerness – about 11,000 people – for as long as it takes to clear the site.
Fellows is not impressed with the idea of entombment. “Burying the ship in concrete will only dampen an explosion,” he says. He suggests that the fragmentation bombs may best be removed by grouting them together into sections using concrete, and then lifting and moving them away from the site underwater. He has used similar techniques to remove fused munitions from HMS Drake, a first-world-war cruiser sunk off the north-west coast of Ireland and HMS Vanguard, a battleship of the same vintage that sank in Scapa Flow, a strait in the Orkney Islands, UK.
But whether this will work for the Richard Montgomery will depend on the circumstances. Fellows says that the government surveys were designed only to monitor the state of the wreck. They are not sufficient to show up stray bombs that have worked their way into the silt, either from the wreck or informal dumping. “You need a bloody good survey in the first place by someone who knows what they’re looking at,” Fellows says.
A spokesman for the Department for Transport confirms that it has had the risk assessment for “two or three years”, but says that publication is not imminent. “We think it needs more work to accurately predict the likely risks of an explosion,” the spokesman says. “In order to do that we need to have a closer look at the state of the munitions.” However the department has yet to commission a survey of the munitions. “We haven’t forgotten about it,” he says. “It’s not going to go away.”
