The Vanguard-class nuclear-powered ballistic missile submarines (SSBNs) of Royal Navy were build by Vickers Shipbuilding and Engineering Limited, which is now owned by BAE systems. First introduced in 1994 as a part of Trident Nuclear Programme, they are the largest submarines manufactured in the UK. The programme includes fours boats: The first of the class, HMS Vanguard was commissioned in 1993, HMS Victorious in 1995, HMS Vigilant in 1996, HMS Vengeance in 1999. All four boats are based Royal Navy base at Faslane in Scotland.
The Vanguard has the capacity to carry 16 Trident missiles. The Trident II or D5 missile (designated UGM-133A) is a strategic submarine-launched ballistic missile (SLBM) manufactured by Lockheed Martin Missiles and Space. The missiles carried a number of multiple independently targeted re-entry vehicles (MIRVs), each armed with a yield of 100kt to 120kt.
In addition to the missile tubes, the submarines are fitted with four 21 inch (533mm) torpedo tubes and carry the spearfish heavyweight torpedo, allowing them to engage submerged or surface targets at ranges up to 65 Kms (40 miles). Two SSE Mark 10 launchers are also fitted, allowing the boats to deploy Type 2066 and Type 2071 decoys and the submarine’s electronic support measures (ESM) intercept system is the UAP Mark 3 supplied by Thales Defence.
The boats are equipped with the Thales Underwater Systems Type 2054 composite sonar. The Type 2054 is a multi-mode, multi-frequency system, which incorporates the 2046, 2043 and 2082 sonars. The Type 2043 is a hull-mounted active/passive search sonar, the Type 2082 is a passive and ranging sonar, and the Type 2046 is towed array sonar operating at very low frequency providing a passive search capability. Lockheed Martin UK was awarded a seven-year contract in September 2006 to upgrade the Type 2054 sonar systems, the upgrade includes open architecture processing using COTS ( commercial-off-the-shelf) technology, based on the ARCI (acoustic rapid COTS insertion) model that has been in the service with the US Navy since 1998. The upgraded system entered the service in 2009. Two periscopes are carried, a CK51 search model and a CH91 attack model. Both have TV and thermal imaging cameras in addition to conventional optics.
The boat’s main nuclear powered propulsion system is based on the second-generation Rolls-Royce PWR 2, which was developed specifically for the vanguard class. Current generations of PWR allow submarines to circumnavigate the world about 20 times, whereas the latest development of PWR would allow circumnavigation 40 times without refuelling. The other main items of machinery are two GEC turbines, and a single shaft with a pump jet propulsor. There are two Paxman diesel alternators, and two turbo generators from WH Allen. The propulsion system provides a maximum submerged speed of 25 knots (46kmph/ 29mph).