Swiftsure class SSN (1971)

The Swiftsure class were six nuclear-powered fleet submarines, next-gen built in the 1970s and in service until 2010. They were all built at VSEL Barrow (Vickers) for the Royal Navy from 1969 when Swiftsure was laid down to 1981 when Splendid was completed so across twelve years. The design was much improved compared to the previous Valiant/Churchill class, with a new cyclindrical section hull, much fuller, and only the bow keeping its former shape. More importantly they were fitted (all but the lead boat) with a shrouded propeller (pump jet), could dive deeper and were much quieter. Swiftsure herself shadowed from very very close the newly completed aicraft carrier Kiev, collecting its acoustic signature and taking underwater photos of her hull and propellers. More will be probably declassified in the coming decades on their cold war missions. The class started to be decommissioned in 1992 and up to 2008, with a long process of recycling probably going on from 2022 to 2035 or more, followed by the Trafalgar.

Swiftsure was decommissioned earlier in 1992 due to various issues, never really fixed. Splendid was victim in 2004 of budget cuts, Spartan in January 2006, and Sovereign on 12 September 2006 and Superb on 26 September 2008 following the standard schedule, Sceptre in December 2010, and not replaced, as the follow-up Trafalgar-class only were replaced by the Astute-class. During their largely uneventful career (ast least officially) they were upgraded to operate the Tomahawk cruise missile and addition to their torpedoes, mines and anti-ship missile, 1st class of RN submarines to be built with shrouded pump-jets. #royalnavy #coldwar #hmsvaliant #nuclearattacksubmarine

Development

Cutaway of Swiftsure, showing the absence of pump jet prop. (from pinterest via reddit)

HMS Dreadnought as well as the Valiant and sub-class Churchill had the typical “whale-shaped hull” designed back in 1960 which was estimated to be a near-perfect streamlining for maximum underwater efficiency. This British design still was at least very influenced, if not based based US Navy studies for USS Albacore and the following Skipjack class SSNs. Still, many conidered the US streamlining, especially fore and aft, to be purer. For the next generation of SSNs, it was decided to look for a different shape, more cylindrical than “pear-like”, and essentially and maintained a constant diameter on a much greater length.

The internal space optimisation while using roughly the same accomodation led to a samaller design overall, with 13 ft (4 m) less in overall lenght, thanks to a fuller form and with fore-planes set further forward, but one less torpedo tube. The more cyclindrical shape also proved stronger, partly due to the steel used, but mostly the shape, whioch gave this class a deeper diving depth. In short, they had a constant cylindrical shape for most of the lenght, a relatively wide and stubby tail, rounder in shape, but the same “whale head” like nose. They looked more like US submarines such as the Sturgeon/Los Angeles, although being smaller than the latter. Internal volume was greater in general, which offered a number of advantages. The hull was divided into three full decks, offering more space than previous designs. See also this article and cutaway on the next Trafalgar class on HI sutton to have an idea.

The propulsion was the other innovation. Although the nuclear reactor was the same Rolls-Royce pressurized water nuclear reactor (PWR1), the biggest change was to discard the seven/nine-bladed propeller of previous classes, for a shrouded pump-jet propulsor. The principle was to surround the propeller into a cylindrical shroud, so the blades’s disturbances were funneled in a completely different way and almost cancelled. The prototype was installed and tested already on HMS Churchill. HMS Swiftsure, the lead boat, was however not fitted with a propulsor.

This system not only was 50% more efficient than a propeller while keeping the same speed, at lower revolutions, and greatly further reduced the noise signature. The RN was the first to adopt this system, always trying to reach the most silent boat type achievable for the “silent service”. In addition to other, further improvements to the rafting of all propulsion elements, new outer hull coating, rubberized paneling inside, pipework connections to equipment on the main machinery raft and new expansion/flexible coupling connections. All contributed to reduce noise further.

It was so advanced that the US Navy secured a licence to copy the main shaft flexible coupling on later variants (Blocks) of the Los Angeles class. Still, not all was rosy with the dhrouded prop, notably it was heavy, complicated and inscreased drag. This explaine perhaps the lead boat Swisftsure was completed without, but this did no prevented her success in operation, such as a noew declassified Operation details, when spent hours under the newly completed Soviet hybrid CV, Kiev, taking pictures of her propulsion, sonar and towed sensor in particular, a crucial intel feat for NATO.

Design of the class

Hull and general design

So, as described above, the Swiftsure class had a near constant hull, with the same “faceted” nose like on previous designs, but symmetrical, and a much full, stubbier tail with englarged fins and tails with the same old “+” arrangement. The pump jet was not ready yet when the first boat was completed. The Swiftsure class were ordered at Vickers Shipbuilding and Engineering, Barrow-in-Furness at a rate of one every year/two/three years depending on budget (or lack thereof): 1967, 1969, 1970, 1971, 1973 and 1976. Due to this, S106 HMS Spendid was completed in 1981, whereas the first of the Trafalgar class was already planned and laid down in 1979.

The Swiftsure class reached 4,400 t (4,850.17 short tons) standard in displacement and 4,900 t (5,401.33 short tons) submerged like the Churchill class but were shorter at 82.9 m (272 ft), narrower at 9.8 m (32 ft) but with a greater draught at 8.5 m (28 ft) versus 8.2 m (27 ft).

Powerplant

The Swiftsure class had two sets GEC-Alstom geared steam turbines, fed in turn by the very same Rolls-Royce PWR-1 as the previous classes for 15,000 hp, however it was rafted in such as way as to be even more discreet while providing the same overall performances, the drag being compensated by the speed gain from the pump jet propeller. The top speed is noted “in excess of 28 knots (52 km/h)” underwater, 20 knots surfaced. and the range and autonomy were only limited by the food onboars and crew fatigue, up to 90 days for a large crew of 116 (13 officers) compared to the Churchill’s 103. The wiftsure could also dive below 300 meters (984 ft).

Armament

Torpedo Armament

This no longer the same armament as the Churchill/Valiant of 32 torpedoes notably the Tigerfishn Mark XXC and XXIII and after 1982, the Harpoon and Tomahawk.
The bigger different was the use of five tubes instead of six. But in the 1980s the addition of longer range weaponry was quite a game changer, unlike the previous classes.

Mark 20C Torpedo:

An improvement of the Mark 20S Torpedo, first British passive homing torpedo entering service in 1955. The Mark 20C was developed in the early 1960s, susperseded by the Tigerfish in the 1980s.
They were “short” torpedoes and used notably in the Oberon’s rear tubes.
⚙ specifications Mark 20C:
Weight 1,810 lbs. (821 kg)
Dimensions: 254.5 in (6.464 m)
Propulsion: Battery
Range/speed setting: 7,000 yards (6,600 m)/23 knots
Warhead: 196 lbs. (89 kg)
Guidance: Homing, active/passive

Mark 23 Grog:

A wire-guided version of the Mark 20 with dual-speed mode, tested from 1955 and worked on further after “Mackle” project was cancelled in 1956. The first were delivered in 1959 but it entered service in 1966, and considered already obsolescent, not operational until 1971. But they were never popular as thir control system was failing at extreme range.
⚙ Specifications Mark 22 Grog
Weight: 2,000 lb (907 kg)
Dimensions: 14.9 ft (4.54 m) x 21 in (530 mm)
Propulsion: Battery (perchloric acid)
Range/speed setting: 12,000 yd (11,000m)@20 knots, 8,900 yd (8,100 m)@ 28 knots
Warhead: 89 kg (196 lb) Torpex
Guidance: Wire-guided to point, passive sonar acquisition for terminal guidance

Mark XXIV Tigerfish:

Despite many issues, the 1950 program initially setup to deliver an operational model in 1969 was too ambitious and technically complex to meet its original target. This 55-knot (102 km/h; 63 mph), deep-diving torpedo was driven by an internal combustion engine using high pressure oxygen as oxidant. It was guided by a wire system developed from the Mackle project in 1952. It used data transmitted from the firing submarine sonars during its wired run, until detached and completed its race to the target after acquisition using an autonomous active/passive sonar developed from the abandoned 1950s UK PENTANE torpedo project. This was also known as Project ONGAR and engineers were so confident in its superiority it was described as “…the end of the line for torpedo development”. The Mk 24 Tigerfish entered service in 1970, followed in the 1990s by the Spearfish.
⚙ Specifications Mark 24 Tigerfish
Weight: 1,550 kg (3,417 lb)
Dimensions: 6.5 m (21 ft) x 533 mm (21 in)
Power unit: Electrical, chloride silver-zinc oxide batteries 35-knot
Maximum range: 39 km (43,000 yd) at low speed, 13 km (14,000 yd) at 35 kts
Warhead: 134 to 340 kg (295 to 750 lb) Torpex
Guidance: Wire-guided to point, passive sonar target acquisition/terminal homing.
Next torpedo to cover: The Spearfish (Swiftsure class).

RGM-84B Sub-Harpoon:

The cancellation of the Undersea Guided Weapon programme led to purchase instead the Sub-Harpoon to give SSNs a long range capability strike. Normal provision was six of them, replacing torpedoes. Trials started in October 1981. This purchase was followed by the selection of the latest surface version, the RGM-84C, as the successor to the Exocet.
In short: Size 4.63 m x 0.343 m, 683 kg, Teledyne J402-CA-400 turbojet + booster, Mach 0.9, range 130 km.
Payload 221 kg WDU-18/B penetrating HE-fragmentation with delayed impact fuse.
Guidance: Initial phase Inertial navigation, final Active radar homing, sea skimming.

BGM-109 Tomahawk:

Introduced in the early 1990s, Block II TLAM-N: 1,350 nmi (1,550 mi; 2,500 km) at 570 mph (500 kn; 920 km/h) with 1,000 pounds (450 kg) high explosive or submunition dispenser. In 1995, the US agreed to sell 65 Tomahawks of the torpedo-launch variant, the first missiles acquired and test-fired in November 1998, but not all Trafalgar and Swiftsure were capable of operating it, the Astute-class however integrated it from the start. The Kosovo War in 1999 saw the Swiftsure-class HMS Splendid become the first British submarine to fire a Tomahawk in combat. 20 more Block III were later purchased to replenish stocks. They were also used in 2000s Afghanistan War, Operation Telic, 2003 Iraq War, and Operation Ellamy in Libya in 2011.

Stonefish and Sea Urchin mines:

Two could fit and take the place in the tube of a torpedo, they had the same diameter.
Stonefish mine: Developed by BAE for the RAN initially it had a warshot with incremental payload, generally with an aluminised PBX warhead base. It existed in four variants. Src
Sea Urchin mine: It was also developed by BAE (British Aerospace) in the early 1980s with a variety of warhead (250 kg, 500kg, and 750 kg) and common sensing, fuzing, and arming system combining acoustic, magnetic, and pressure sensors. It seemed to have been tested but never purchased.

Sensors

The whole suite comprised a Bow, flank, active intercept, and towed array sonar. For periscopes these were attack and search models and there was a collision avoidance radar when surfaced.
Type 1003 radar:Operating in X-band, surface+air warning and ranging. Type AKU(3) or AKS(2) antenae, derived from the 1002 radar.
Type 2001 sonar: Hull-mounted, low-frequency, detection sonar designed for nuclear-propelled submarines. Active and passive with an array of 24 flat panels carrying 56 transducers. producing 24 active search beams with a beam tilts down 20 degrees. Sonar type developed specifically for HMS Dreanought.
Type 2007 sonar: Hull mounted long-range passive sonar, upgraded from the Oberon class.
Type 2023 sonar: No data
UAB/UAC ECM suite: No data
DCB CCS: No data.
SSE Mk 8 decoy launchers. No data.

Conway’s profile of the Swiftsure class

Upgrades

In 1984, HMS Sovereign followed by Superb in 1986 and Sceptre in 1987 had their 2001 sonar replaced by 2020/2024 suite and the addition of Sub-Harpoon SSM (four UGM-84B instead of torpedoes). Spartan in 1989 and Splendid in 1991 only had the type 2024 sonar/sub-harpoon upgrade
In 1997-98 Sovereign and Superb and later in 2001 Sceptre as well as in 2003 Spartan had their type 1003 radar, type 2020/2024 sonars ECM suite and CCS removed and a comprhensive upgrade with the type 1006(1) radar, type 2074, type 2046, type 2077 sonars as well as the UAP(1) ECM suite and the type 2066, 2071 torpedo decoys as well as the DCB/DCG CCS. In 1998-1999, Splendid and Spartan were the only ones pgraded to fire and operate the Tomahawk (4 UGM-109 carried) wherea sin 2008 Sceptre lost its Sub-Harpoon.

Career of the Valiant class

Swiftsure, a name previous bore by ship of the lines, two battleship and a cruiser was built at Vickers Shipbuilding and Engineeringin Barrow-in-Furness, ordered on 3 November 1967, laid down on 6 June 1969, launched on 7 September 1971 and completed on 17 April 1973 at a cost of £37,100,000 (£165.38 million 2023). Most of her career remains classified, but Swiftsure was made famous for her mission to acquire the acoustic signature of the Kiev. The collection of a new unique acoustic sound that would betray their presence was added to the database of NATO subs. She hid underneath for several hours, raised the periscope 10 feet (3.0 m) under her hull, to take photographs. All was aired in 2013 in BBC’s Cold War season.
She had a refit at Devonport in January 1979, delayed until April 1980, and then announced completed by mid-1982 but it was in March 1983 for £85 million.
Her second refit was planned by 1992, but she was decommissioned instead. Ppressure hull damage in sea trials was believed as the main reason, but it had been debunked since by an inspection revealing cracks in her reactor hull in refit. The core was safely removed in June 1992.
She was stored afloat in the non-tidal basin at Rosyth waiting for her turn at the Submarine Dismantling Project (SDP), periodic dockings for re-preservation and maintenance inspections. The last was performed in 2016 onwards and she became the demonstrator for Initial Dismantling, in 2023, it was reported to be completed by 2026.

Ordered on 16 May 1969 she was laid down on 18 September 1970, launched on 17 February 1973, completed on 22 July 1974, commissioned 11 July 1974 at a cost of £31,100,000 (£97.73 million). In 1976, she took part in Operation Brisk surfacing at the geog. North Pole on 20 October 1976 during an exercise, and testing her navigational systems and equipment in polar temperatures. This 21 October 1976 she was halfway between the Geographic North Pole and northern tip of Ellesmere island in a coordinated operation with the Canadian Forces Maritime Proving & Evaluation Unit (MP&EU) based at CFB Summerside at Prince Edward Island. This long term project tried to evaluate airborne remote sensing devices (SLAR, ILRS and Laser Profilometer) for under and through-ice surfacing imaging.
She had a main overhaul in the mid-1990s, ending in January 1997 buy like her sister, cracks were discovered in the tailshaft while in post-refit sea trials and she was sent to Rosyth for 14 weeks of emergency repairs by June 1998.
She provided the “Perisher” Submarine Command Course in June 1999 and took part in NATO exercise Linked Seas in May 2000, in the Bay of Biscay.
Reactor problems kept out her of service in the 2000s due to a fault shared by all six boats in the class, but back into service by July 2005. Despite of this it was cided to have her decommissioned by September 2006. Like Swiftsure, she is next in line in the British recycling and dismantling program, with a entering date yet to be announced.

Superb was ordered on 20 May 1970, laid down on 16 March 1972, launched on 30 November 1974, completed on 29 November 1976 and commissioned prior on 13 November at a cost of £41,300,000 (£129.78 million). She was the first British submarine to sail to the Arctic Ocean and stay under the polar ice caps.
The Falklands War saw her leaving Gibraltar, and whe spotted it fed speculation as she was heading towards the South Atlantic. It was not the case but this apparent threat was not corrected by the Navy or Ministry of Defence to leave the Argentinian in the blind (typical strategic ambiguity case).
Superb was seen in operations in the Indian Ocean in 2001 for Operation Veritas, her take in the war on Afghanistan.
The 2008 underwater pinnacle collision wa sprobably the most serious declassified incident.

On 26 May she hit an underwater pinnacle in the Red Sea, some 80 miles (130 km) south of the Suez Canal. No leak, no injuries but still she was unable to re-submerge, having a damaged sonar. Initial repair were performed at Souda Bay (NATO base) on 10 June 2008, and she stopped on the way home to Gibraltar to disembark some crew and arrived at Devonport on 28 June 2008. The Royal Navy after inspection proposed to decommission her ahead of schedule on 26 September 2008. two years after the commanding officer and two other officers were reprimanded, pleaded guilty to charges but they were were still in the Royal Navy during the court-martial.

Sceptre was ordered on 1 November 197, laid down on 19 February 1974, launched on 20 November 1976 and completed on 11 March 1978, commissioned on 14 February 1978 at a cost of £58,900,000 (£185.09 million). On 23 May 1981 Sceptre collided with Soviet K-211. Her reactor safety systems performed an automatic emergency shutdown (scrammed) albeit the captain ordered these safety mechanisms to be overridden and to report they had hit an iceberg. When examined back to port in drydock, it was discovered her forward outer casing was torn away, fin damaged and bridge completely mushed. The propeller of the Russian sub tore through her pressure hull. This was disclosed when David Forghan (former weapons officer) in a television interview broadcast on 19 September 1991. K-211 was one of the Delta III SSBNs, reporting colliding on 23 May 1981 with an unknown submarine, and at the time believed to be a Sturgeon-class USN sub, which was refuted by the Pentagon.
In 1987 Sceptre had her core changed to the Core Z and in March 1990, it had coolant leak while at Devonport. On 20 October 1991, a fire was declared onboard when moored at Faslane, quickly mastered. In August 1995 she was forced to abort her patrol and return to Faslane after what was reported by the MoD as an “an unspecified fault in the propulsion system.” The issue common to the class was discovered in 1998, but it ws only traken seriously after another investigation and serious accident.
In November 2010 she snagged the nets of the fishing vessel Scotia in November 1989.
On 6 March 2000 while in the drydock at the Rosyth yards and undergoing trials at the end of her major major refit she had a serious accident. It ws required to flood the drydock, running the main engines slowly with steamfrom the shore but it was done in excess, the engines went to full speed and she broke her moorings and banged the cradle she rested on, rupruting her steam line while moving 20 yards (18 m).
Sceptre’s reactor problems ultimately led to the recommended that she was better to be scrapped and by January 2002, still laid up, another inspection revealed “small original fabrication imperfections” in the reactor pressure vessel. After her last refit by March 2003 she left Rosyth for new sea trials and by late October 2003 returned to active service.
On 3 February 2005, she was back in Gibraltar for repairs, with again, damage in the cooling system, but reported to Spanish authorities to come from the diesel generator and not nuclear propulsion system. In reality this was a leak in her reactor coolant system. Foreign Minister Miguel Angel Moratinos protested and argued that she would be last British submarine ever repaired at Gibraltar. Repairs were announced completed by 7 February 2005 and she left Gibraltar on 9 February.
She was sent to the Falklands to support the British garrison in March 2010 linked to Desire Petroleum’s exploratory oil drilling. She entered Devonport for the last time in May 2010, decommissioned on 10 December 2010 (after 32 years of servic) in a ceremony was witnessed by 450. By 2020, she remained in HMNB Devonpor awaiting dismantling. Given the other scheduled, it might well be completed beyond 2030.

She was ordered on 7 February 1973, laid down on 26 April 1976, launched on 7 April 1978, completed on 10 October 1979 and commisssioned prior on 22 September 1979 at a cost of £68,900,000 (£216.52 million 2023). Soon after entering service she sailed for the Falkland Islands, two days before the Argentine invasion on 30 March 1982. She was the first to arrive and enforce the newly imposed 200-mile (320 km) maritime exclusion zone. She sighted Argentine merchant shipping mining the harbour at Stanley as reported, but was denied attack.
It was vital to avoid such kills early one to preserve more interesting targets such as the carrier ARA Veinticinco de Mayo. On 1 May she started shadoing her Veinticinco outside the Argentinian 12-mile (19 km) limit,. She was eventually recalled to the Northwood fleet command against task force commander Admiral Woodward who wanted to retain full control on his submarines. Veinticinco de Mayo was thus left unchecked by submarines, and this enabled the latter to launch an A-4Q Skyhawk from closer range on the task force with dire consequences. Unlike HMS Conqueror, Spartan only provided valuable reconnaissance.
In November 2010, she apparently was reported to have running aground off the west coast of Scotland back in October 1989.
HMS Spartan had been decommissioned in Juanry 2006, she is in reserve since at Devonport. She is now waiting for her turn of recycling. No date is given.

Initially ordered as Severn on 26 May 1976 she was laid down on 23 November 1977, launched on 5 October 1979 and completed on 5 May 1981, commissioned on 21 March 1981 at a cost of £97,000,000 (£304.82 million). She, too served in the 1982 during the Falklands War and one of the first submarines there by mid-April from Faslane. She shadowed several ships and monitored coastal movements, planes launches, ships departure, providing intel, shadowed the carrier 25 de Mayo, while staying just a mile outside of the Argentinian territorial line.
As he was on the edge of the exclusion zone around the Falklands, the captain reporting having the right in international law and approval from the British PM, to fire at the carrier and prepared MK 8 torpedoes for this, also confirming his precise position. He however lost sight and could not regain contact before the carrier was too far away. Admiral Sandy Woodward precised however that any fire was to be under approval of the PM. Like other British SSNs she still became a threat which had the Argentinian navy later confined to port after the sinking of Belgrano.

In November 1998, the Royal Navy acquired and tested the Tomahawk cruise missile which deployment started witrh HMS Splendid for operational certifications. In March 1999, she fired Tomahawks on Serbian targets as part of NATO inteventional in Kosovo, first British submarine lifez firng on, targets. 20 Tomahawks were spent in this war and more against Iraqi targets in the 2003 invasion. In July 2003 Splendid was back at Faslane (River Clyde) in Scotland to be later decommissioned in HMNB Devonport in Plymouth in 2004. Commander Burke was awarded the OBE for his Gulf war deployment.
HMS Splendid was alleged present near Kursk when she sank according to Russian officials as well as USS Memphis and USS Toledo, interested by Russian war games. Independent forensic inquiries mitigated the case, which was dropped when the Russian themselves admitted this was due to a faulty torpedo, likely the new Shkval using a highly unstable fuel. Conspiracy theories in Russian however never accepted this.
The problem until today for these claims are that positions and logs of submarines post 1960 are classified and will remain so for the foreseable future.

Read More/Src

Books

Conway’s all the wporld’s fighting ships 1947-1995, page 531.

Links

navypedia.org/
https://www.battleships-cruisers.co.uk/swiftsure_class1.htm
http://rnsubs.co.uk/boats/subs/swiftsure-class.html
https://www.iwm.org.uk/history/life-on-board-a-british-nuclear-submarine
https://www.navypedia.org/ships/uk/brit_ss_swiftsure.htm
https://web.archive.org/web/20150924155750/http://www.highbeam.com/doc/1G1-54879482.html
https://web.archive.org/web/20140714140743/http://www.rnsubs.co.uk/Boats/BoatDB2/index.php?BoatID=693
https://web.archive.org/web/20150924163747/http://www.highbeam.com/doc/1G1-79025940.html
https://www.twz.com/how-a-british-submarine-spent-hours-under-a-russian-aircraft-carrier
https://www.royalnavy.mod.uk/news/2024/october/22/20241022-crew-take-final-look-at-old-s-boat-before-submarine-dismantling-programme-begins
https://www.seaforces.org/marint/Royal-Navy/Submarine/Swiftsure-class.htm
https://www.militaryfactory.com/ships/detail.php?ship_id=hms-swiftsure-s126-nuclear-attack-submarine-united-kingdom
en.wikipedia.org/ Valiant-class_submarine
https://api.parliament.uk/historic-hansard/written-answers/1976/nov/15/shipbuilding#S5CV0919P0_19761115_CWA_235
https://api.parliament.uk/historic-hansard/written-answers/1977/nov/24/warship-building#S5CV0939P0_19771124_CWA_263
http://news.bbc.co.uk/2/hi/uk_news/scotland/666943.stm
http://news.bbc.co.uk/2/hi/uk_news/7422774.stm
http://news.bbc.co.uk/2/hi/uk_news/england/devon/7638229.stm

Videos

Launch of Swiftsure, British Movetone See also.

Model Kits

More conversion sets, HMS Splendid, Airfix 1:350 and Jagd-U-Boot HMS Superb 1:700 by ARII 1:700. REF REF2
sdmodelmakers.com trafalgar-class
By Skytrex, metal, waterline

3D

3D printed version