HMS Vanguard and Le Triomphant submarine collision HMS Vanguard and Le Triomphant submarine collision The submarines HMS "Vanguard" and "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 and the French Navy's both sustained damage, but no injuries or radioactivity releases 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. HMS "Vanguard" was on a routine patrol in the Eastern
HMS Vanguard and Le Triomphant submarine collision Clyde, on 14 February 2009 and "Triomphant" to Île Longue in Brittany, escorted by a frigate as a normal procedure, although it is unclear whether this was an unplanned return following the incident. On 5 May 2015 the Trident whistleblower William McNeilly described the incident as told to him by a Chief on "Vanguard" at the time: Media reports have discussed two possible aspects contributing to the incident; geographic separation of the submarine operating areas (known as waterspace management), and the ability of each submarine to detect the other using acoustic methods. While the use of active sonar may have