The British Swiftsure class was the fourth design of nuclear-powered fleet submarines commissioned for service with the Royal Navy from the early 1970s until 2010. HMS Swiftsure was ordered on 3 November 1967 being laid down at Vickers Armstrong’s Barrow-in-Furness shipyard on 6 June 1969. She was launched on 7 September 1971 and commissioned on 17 April 1973. The cost of building Swiftsure was £37.1 million.
Six of the eight boats intended were built in all; but the leader boat, HMS Swiftsure was decommissioned early in 1992 due, it was thought to damage suffered to her pressure hull during trials. HMS Splendid followed in 2004 after defence cuts caused a reduction in the size of the RN submarine fleet. HMS Spartan was decommissioned in January 2006, with Sovereign following on 12 September 2006. Superb was decommissioned on 26 September 2008. The remaining boat in the class, Sceptre, was decommissioned in December 2010. They are currently being replaced by the Astute-class submarines.
Spartan, Sovereign and Sceptre were upgraded to launch Tomahawk cruise missiles in addition to their original armaments of torpedoes, mines and anti-ship missiles. They were also the first class of Royal Navy submarines to be built with shrouded pump-jet propulsors. Whereas the Dreadnought, Valiant and Churchill classes all had a ‘whale-shaped hull" based on the designs of the US Skipjack and Albacore (See my article on HMS Dreadnought) with near-perfect streamlining giving maximum underwater efficiency. The hull of the Swiftsure class was a different shape and maintained its diameter for a much greater length than previous classes. Compared with the Valiant’s, the Swiftsure’s were still 13 feet shorter but with a fuller form and had their fore-planes set further forward. They also had a much deeper diving depth.
A second major change was in propulsion. Rather than the seven/nine-bladed propeller used by the previous classes, all but the first of the Swiftsure class submarines used the shrouded pump-jet propulsor. The prototype ‘propulsor’ had powered the Churchill. It is not clear why the Swiftsure was the only one of the class not fitted with a propulsor as this was perhaps as much as 50% more efficient than a propeller, producing the same speed at lower revolutions, thus reducing the noise signature. In addition all pipework connections to equipment on the main machinery raft had expansion/flexible coupling connections, which also reduced noise. The US Navy was so impressed by the propulsor, they secured a licence to copy the main shaft flexible coupling arrangement for future US built submarines.
HMS Swiftsure became famous for her mission to acquire the acoustic signature of the Soviet aircraft carrier Kiev. She is said to have 'chanced upon' an enormous military exercise, possibly the Sever-77 exercise and upon locating a new unique acoustic sound that indicated the (then unknown) Kiev's presence, hid underneath her for several hours with her raised periscope just 10 feet under the aircraft carrier's hull, thus allowing the crew to take photos and record the ship's hull shape and acoustic signature. This was a major coup and was documented in 2013 as part of the BBC's Cold War season.
HMS Swiftsure arrived in HMNB Devonport in January 1979 for her first scheduled refit. However, due to an industrial dispute this did not begin until April 1980, some fifteen months after the boat arrived. Despite a statement in the House of Commons in mid-November 1981 that the refit would be completed by mid-1982, Swiftsure's refit was eventually completed in March 1983, at a total cost of £85 million. Swiftsure was due to enter a second refit in 1992, but instead she was decommissioned. The reason for the premature decommissioning was again cited as pressure hull damage suffered during sea trials although that is now thought to be incorrect. It is believed the real reason for the boat's premature decommissioning was due to the finding of cracks in her reactor during a refit. Her nuclear core was safely removed in June 1993.
The Swiftsure class was quickly followed by the Trafalgar class submarine, four of which remain in service today. Using the same design parameters, the Trafalgar’s main difference was its slightly longer length and larger rudder. As there is no model kit of a Swiftsure class submarine, the availability of the 1/350 Airfix ‘Trafalgar’ class provides a means to an end with very little work.
There are three areas where some surgery is required. The major operation is shortening the hull by 7mm. I’d recommend assembling the bottom hull (two sections) first to make the cut(s) more even. The next change requires shaving off about 2mm from the top rudder and finally, add a second vent on either side of the hull. There are some minor adjustments to be made to the sail and periscope arrangement but that can wait ‘till next time!