A British nuclear submarine collided with a French sub in the Atlantic because sophisticated antisonar equipment made them undetectable to each other, it was claimed yesterday.
The French submarine Le Triomphant remained unaware that it had rammed and damaged HMS Vanguard until days later, when it was informed by the Royal Navy. Both vessels were carrying nuclear ballistic warheads while on secret patrols when they crashed this month.
Official inquiries have started in Britain and France, amid concerns regarding the sharing of military information between the allied navies.
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The French Navy claimed this month that the bow sonar dome of Le Triomphant was probably damaged in a collision with a submerged shipping container while returning from patrol. It only discovered that it had hit a British submarine after one of the regular exchanges of information with the Royal Navy.
Nato countries exchange details about the areas and depths in which their submarines will operate during patrols. France has opted out of Nato’s military command, however, so does not share detailed information, although it normally provides some data about its submarine operations.
The First Sea Lord, Admiral Sir Jonathon Band, said that the collision happened at low speed and none of the 240 crew on board the submarines was injured. “Two submerged [ballistic nuclear submarines], one French and the other UK, were conducting routine national patrols in the Atlantic Ocean,” he said. “Both submarines remained safe and no injuries occurred. We can confirm that the capability remained unaffected and there has been no compromise to nuclear safety.”
The collision is understood to have occurred on February 3 or 4. HMS Vanguard returned to its base in Faslane, western Scotland, on Saturday with dents and scrapes on its hull. Le Triomphant took three days to limp home to port in Brest, northwest France, with extensive damage to its Thales DMUX 80 sonar. Repairs to the two vessels are reported to have been estimated at £50 million.
The French Navy confirmed that the collision took place in the Atlantic on a routine patrol and at great depth but would not disclose the location for security reasons.
Captain Jérôme Erulin said that such collisions were extremely unlikely but always possible between two submarines that are designed to evade detection. “It was a brief contact at slow speed,” he said. “The slow speed at the moment of the incident is their normal patrol speed. There was no human error.”
A Royal Navy source said that the chances of two submarines colliding in the mid-Atlantic were very small. He said that submarines used “water space management” to separate themselves both geographically and in depth from other vessels. “It is remarkably difficult to detect a modern submarine with sonar and we work very hard with our own submarines, as do our allies, in making them as quiet as possible so they are not detectable.”
Commodore Stephen Saunders, editor of Jane’s Fighting Ships, said: “This is a very serious incident. There are procedural issues that need addressing. We should not have submarines of friendly nations operating in the same area at the same time.”
HMS Vanguard, which was launched in 1992, is one of four British submarines capable of carrying up to 16 Trident ballistic nuclear missiles with up to eight warheads. At least one of the submarines is on patrol at any time.
The 14,335-tonne Le Triomphant, which entered service in 1997, also carries up to 16 nuclear missiles, with six warheads, and is one of four nuclear-armed submarines in the French fleet.
Vice-Admiral John McAnally, president of the Royal Naval Association, said that it was a “one in a million chance” that the two vessels collided. He said: “It would be very unusual on deterrent patrol to use active sonar because that would expose the submarine to detection.”
Liam Fox, the Shadow Defence Secretary, said that the crash showed the inherent danger of military operations. “For two submarines to collide, apparently unaware of each other’s presence, is extremely worrying. Hopefully, lessons have been learnt.”
Kate Hudson, from the Campaign for Nuclear Disarmament, said: “This is a nuclear nightmare of the highest order. The collision of two submarines, both with nuclear reactors and nuclear weapons on board, could have released vast amounts of radiation and scattered scores of nuclear warheads across the seabed.”
John Large, an independent nuclear analyst who advised the Russian Government after its Kursk submarine sank in 2000, said that the incident could have been far worse. “The real risk is if you have a fire on board caused by the impact,” he said. “Each warhead has about 30kg-50kg [66lb to 110lb] of high explosive around it. That would burn and your plutonium core would burn as well. That would disperse into the atmosphere and be a major problem.”
The incident is the most serious underwater collision since the USS San Francisco hit an undersea mountain in the Pacific head-on in 2005, killing one sailor and injuring 24 others.
Lee Willett, of the Royal United Services Institute for Defence and Security Studies, said that Britain and France would be very reticent to share information on what their nuclear submarines were up to. “Despite how close these relations are, they are the ultimate tools of national survival in the event of war,” he said.