High Quality Content by WIKIPEDIA articles! The submarines HMS Vanguard and Le Triomphant collided in the Atlantic Ocean in the night between 3–4 February 2009. Both are nuclear-powered ballistic missile submarines. The Royal Navy`s HMS Vanguard and the French Navy`s Le Triomphant both sustained damage, but no injuries or radiation leaks were reported. At the time of the collision, both vessels were submerged and, according to the UK Ministry of Defence, moving "at very low speed"; both are equipped with active and passive sonar, although only the latter is used on an operational patrol.