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