The UK Royal Navy currently operates three Trafalgar Class nuclear-powered attack submarines. Credit: US Navy photo by Mass Communication Specialist 2nd Class Amanda R Gray.
HMS Triumph (S93) was commissioned by the Royal Navy in October 1991. Credit: Photo: LA (Phot) Abbie Gadd / MOD.
Trafalgar Class nuclear-powered attack submarine has a maximum speed of 30k. Credit: US Navy photo by Mass Communication Specialist Seaman Zachary Wickline.

Trafalgar Class nuclear-powered attack submarines are in service with the Royal Navy. The submarines were built by Vickers Shipbuilding and Engineering Limited (VSEL), now known as BAE Systems Submarine Solutions.

Trafalgar Class submarines are preceded by Swiftsure Class and succeeded by Astute Class submarines.

The first submarine in the class, HMS Trafalgar (S107), was commissioned in May 1983. The remaining submarines are HMS Turbulent (S87), commissioned in April 1984, HMS Tireless (S88), commissioned in October 1985, HMS Torbay (S90), commissioned in February 1987, HMS Trenchant (S91), commissioned in January 1989, HMS Talent (S92), commissioned in May 1990, and HMS Triumph (S93), commissioned in October 1991.

In December 2009, the Royal Navy decommissioned HMS Trafalgar, the first submarine of the Trafalgar Class. The HMS Turbulent was decommissioned in July 2012, while the HMS Tireless and HMS Torbay submarines were retired in June 2014 and July 2017 respectively.

Trafalgar class submarine design

The design of the Trafalgar Class is identical to that of the Swiftsure Class submarine. The hull of the Trafalgar Class is covered with the anechoic tiles to absorb the sound waves of sonar, making the submarine more difficult to be detected by active sonar.

The Trafalgar Class is 2.5m longer than Swiftsure but has an almost identical internal layout. Equipped with strengthened fins and retractable hydroplanes to sail through thick ice, the Trafalgar Class design also incorporates a new nuclear reactor core and Type 2020 sonar.

The submarine has a length of 85.4m, a beam of 9.8m and a draught of 9.5m. The displacement of the vessel when submerged is 5,298t.

Trafalgar Class command and control

The Trafalgar Class was earlier equipped with a submarine command system (SMCS), developed by BAE Systems Integrated System Technologies (Insyte). The SMCS was replaced with a new submarine command system next-generation (SMCS NG) in December 2008.

The system handles large volumes of information and controls underwater weapons. The information received from the sensors is processed and displayed as real-time images on the command consoles.

Trafalgar Class submarine missiles

The Trafalgar Class submarine is armed with Raytheon Tomahawk Block IV land-attack cruise missiles (TLAM). The missile is fired from 533mm torpedo tubes.

The Tomahawk missile has a range of up to 1,600km and a maximum speed of 885km/h  (550mi/h). It is equipped with a two-way satellite data-link that enables the reprogramming of the missile according to varied battle conditions. HMS Torbay was the first Royal Navy submarine to be fitted with the Tomahawk missile in April 2008.

Submarine torpedoes

The Trafalgar Class has homing torpedoes to attack submarines and surface vessels within a 15km range. It is equipped with five 533mm torpedo tubes that are capable of firing Spearfish torpedoes and missiles.

"Trafalgar Class submarines are in service with the Royal Navy."

The tubes can carry a total of 30 torpedoes and missiles. The Spearfish from BAE Systems is a wire-guided heavyweight torpedo with an active / passive terminal homing sonar. It has a range of 65km at a speed of 60k.

Trafalgar Class countermeasures

The submarine’s countermeasures include two SSE Mk 8 launchers for Type 2066 and Type 2071 torpedo decoys, an acoustic countermeasures system and Eddystone communications-band electronic support measures (CESM) system. The Eddystone system was jointly developed by UK-based DML and Argon ST of the US.

Submarine sensors / radars

The Trafalgar Class is equipped with the Thales Underwater Systems 2076 Stage 5 integrated passive / active search and attack sonar suite with a bow, active intercept, flank and towed array sonars. A collision-avoidance radar is also fitted on the submarine.

In February 2010, Thales UK was awarded a contract by BAE Systems to upgrade three Trafalgar Class and three Astute Class submarines with the Sonar 2076 Stage 5 system. The new system replaced the 2076 Stage 4 system.

Trafalgar Class submarine nuclear propulsion

The Rolls-Royce PWR1 pressurised water-cooled nuclear reactor provides nuclear power to the submarines. The PWR 1 is a first-generation nuclear reactor developed for the Valiant Class submarines. The reactor powers two General Electric steam turbines, delivering 15,000shp to one shaft.

The Trafalgar Class is also equipped with two WH Allen Turbo Generators, two Paxman diesel alternators, an emergency drive motor and auxiliary retractable propeller. The propulsion system provides a maximum speed of 30k.