The British submarine HMS Vanguard and France's Le Triomphant struck each other on 4 February 2009 while running separate deterrent patrols deep in the Atlantic. Officials from both countries confirmed the accident, emphasizing that neither vessel suffered a radiation leak and no crew members were injured.
Each submarine spans roughly 150 meters and can carry up to 48 nuclear warheads across 16 missiles. A combined 250 sailors were aboard when the vessels made contact at very low speed. HMS Vanguard returned under its own power to its Faslane base in Scotland for repairs; Le Triomphant, its forward sonar dome damaged, had already docked at Ile-Longue near Brest. France's defense ministry had initially described the damage as a collision with a submerged object, possibly a floating cargo container.
Military analyst Stephen Saunders of Jane's pointed to three possible causes: a breakdown in NATO waterspace coordination procedures, the sophisticated stealth engineering of both vessels preventing mutual acoustic detection, or plain misfortune at depth. French navy spokesman Captain Jerome Erulin said the collision was "the first incident of its kind in more than 400 patrols."
Historical summary. TurkishPress restated this wire report, first published in February 2009, in its own words.