The Trafalgar class submarines are, until the introduction of the Astute class, the Royal Navy's most advanced nuclear fleet submarines (SSNs).

The Trafalgar class includes seven boats: Trafalgar (S107), Turbulent (S87), Tireless (S88), Torbay (S90), Trenchant (S91), Talent (S92), and Triumph (S93). It is an attack submarine and is essentially a refinement of the Swiftsure class, designed six years later than its predecessor. The first Trafalgar class submarine was completed in 1983.

The major improvements include a new reactor core and the Type 2020 sonar. Internal layout is near identical to the Swiftsure and it is only 2½ metres longer.

Rather than the seven-bladed propeller used by the Swiftsures, Trafalgar class submarines use pump-jet propulsion - a high pitch, low-revolution propellor which is much quieter but much heavier than conventional propeller designs. Development of this system was not complete in time for installtion in the class's name-ship vessel, HMS Trafalgar, and so the pump-jet was first used in the second in the class, HMS Turbulent.

General Characteristics

• Builder: Vickers Shipbuilding and Engineering Ltd
• Displacement: 4,750 tons surfaced, 5,208 tons submerged
• Length: 85.4 meters
• Beam: 9.8 meters
• Draught: 9.5 meters
• Complement: 18 officers, 112 ratings
• Propulsion: 1 x pressurized water cooled nuclear reactor delivering 15,000 shp for 30 kt max
• Armament: five tubes capable of firing:
  • Spearfish torpedoes
  • Tigerfish torpedoes
  • Harpoon missiles
  • Tomahawk missiles (Trafalgar and Triumph only)
• Sensors:
  • sonar (bow, flank, active intercept, and towed arrays)
  • periscopes (attack and search)
  • collision avoidance radar