The Trafalgar-class group of nuclear-powered attack submarines was adopted by the British Royal Navy (RN) in the mid-1980s to succeed the Swiftsure-class of 1970s origin. The new boats were larger, heavier and more efficient than the type they replaced and similarly numbered seven in all. HMS Trafalgar (S107) was the lead ship-of-the-class and was laid down by Vickers Shipbuilding and Engineering of Barrow-in-Furness on April 25th, 1979. She was launched on July 1st, 1981 and officially commissioned into service on May 27th, 1983. She led an operational existence until decommissioned on December 4th, 2009.
As of December 2017, just three of the original boats - Trenchant, Talent and Triumph - remain in active service.
The Trafalgar-class was more or less an extension of the previous Swiftsure boats. The hulls were of greater dimension and attention was paid to reducing the acoustic signature even further by the use of anechoic sound-absorbing tiles. HMS Trafalgar lacked the shrouded pump-jet propulsor unit fitted to the rest of the boats and relied, instead, on a conventional propeller. Dimensions included a length of 280 feet, a beam of 32 feet and a draught of 31 feet. Power was from a Rolls-Royce PWR1 series reactor coupled to 2 x GEC steam turbines, 2 x WH Allen turbo generators and 2 x Paxman diesel alternators. Submerged speeds could reach beyond 30 knots and range was essentially unlimited due to the nuclear fit.
Aboard was a crew of 130, a decided increase from the 116 personnel featured in the Swiftsure boat class. Beyond the standard 5 x 21" (533mm) torpedo tube armament, the Trafalgar - and all her class - were equipped to fire the American Tomahawk cruise missile (Block IV).
The vessels were given a conventional submarine shape with tapered bows and sterns. The sail was set ahead of midships and the tailplane arrangement a cruciform pattern. The top of the deck was relatively flat with the line running this way most of the length of the boat. For their time, the Trafalgar-class were very advanced undersea boats noted for their low acoustic levels and effective intelligence-gathering capabilities.
HMS Trafalgar has a career blemish when she was run aground in 1996 near the coast of Scotland (Isle of Skye). She did, however, manage to see combat actions prior to her retirement in 2009 when the boat participated in "Operation Veritas" during 2001 (following the events of 9/11). Cruise missiles were launched against Al-Qaeda / Taliban positions in Afghanistan in the operation. In March of 2002, she returned to British home waters but, that November, she ran aground yet-again resulting in damage and a few reported injuries.
The Trafalgar-class has since been succeeded by the Astute-class with will number seven boats (three are in service as of this writing).