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Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 07 Jun 2015, 23:22
by SKB

The Trafalgar-class is a class of nuclear-powered attack submarines in service with the Royal Navy, the successor to the Swiftsure class. Like the majority of Royal Navy nuclear submarines, all seven vessels were constructed by Vickers Shipbuilding and Engineering in Barrow-in-Furness, Cumbria. With three boats still in commission and four retired (May 2019), the class still makes up the majority of the Royal Navy's nuclear-powered ‘hunter-killer’ submarine force. The Trafalgar class is being gradually replaced by the larger Astute class submarine. The name Trafalgar refers to the Battle of Trafalgar fought between the Royal Navy and the combined fleets of France and Spain in 1805.

Submarines from the class have seen service in a wide range of locations, and have fired missiles at targets in Afghanistan, Iraq and Libya. HMS Torbay, Trenchant, Talent, and Triumph have been fitted with the Sonar 2076 system, which the Royal Navy described as the most advanced sonar in service with any navy in the world.

The first Trafalgar-class submarine, HMS Trafalgar, was ordered on 7 April 1977 and completed in 1983. Turbulent was ordered on 28 July 1978; Tireless on 5 July 1979; Torbay on 26 June 1981; Trenchant on 22 March 1983; Talent on 10 September 1984; and finally Triumph on 3 July 1986. In 1982, Jane's Fighting Ships recorded: "Estimated cost of fourth submarine £175 million including equipment and weapon system when fitted." In 1986, Jane's recorded that the average cost for this class was £200 million at 1984-5 prices.

In 1993 Triumph sailed to Australia, covering a distance of 41,000 miles (66,000 km) whilst submerged and without any forward support. This marked the longest solo deployment by any British nuclear submarine.

Three of the Trafalgar-class boats have been involved in conflicts which on each occasion saw the launch of live cruise missiles. In 2001 Trafalgar took part in Operation Veritas, the attack on Al-Qaeda and Taliban forces following the 9/11 attacks in the United States, becoming the first Royal Navy submarine to launch Tomahawk cruise missiles against Afghanistan. On 16 April 2003, Turbulent was the first Royal Navy vessel to return home from the invasion against Iraq, Operation Telic. She arrived in Plymouth flying the Jolly Roger after having launched thirty Tomahawk cruise missiles.

In March 2011, Triumph participated in Operation Ellamy, firing Tomahawk cruise missiles on 19 March and again on 20 March at Libyan air defence targets. The MOD also confirmed that on 24 March a further series of missiles were fired into Libya by a Trafalgar-class submarine at air defence targets around the city of Sabha. The boat involved in this attack was later revealed to have also been Triumph. Triumph returned to Devonport on the 3 April 2011 flying a Jolly Roger adorned with six small Tomahawk axes to indicate the missiles fired by the submarine in the operation.

The class is based at HMNB Devonport, in the city of Plymouth, England.

The Trafalgar class was to be replaced by the Future Fleet Submarine, however this project was effectively cancelled in 2001 and replaced by the Maritime Underwater Future Capability. The Astute class will eventually replace the Trafalgar class as well as the now-retired Swiftsure. As of 2008 it is planned that the last Trafalgar-class submarines will remain in service until 2022.

Service problems
The Trafalgar class have suffered from technical difficulties. In 1998, Trenchant experienced a steam leak, forcing the crew to shut down the nuclear reactor. In 2000 a leak in the reactor primary cooling circuit was discovered on Tireless, forcing her to proceed to Gibraltar on diesel power. The fault was found to be due to thermal fatigue cracks, requiring the other Trafalgar-class boats, and some of the remaining Swiftsure-class boats, to be urgently inspected and if necessary modified. In August 2000 it was revealed that with Tireless still at Gibraltar, Torbay, Turbulent, Trenchant and Talent were at Devonport for refit or repair and with Trafalgar undergoing sea trials, only one boat, Triumph, was fully operational. By 2005, refits had reportedly corrected these problems.

In 2007, a small explosion aboard Tireless resulted in the death of two sailors and injury of another. The accident took place while the submarine was submerged under the Arctic icecap during a joint British-American exercise. An oxygen candle in the forward section of the submarine was thought to be responsible for the accident.

In 2013 the Defence Nuclear Safety Regulator reported that the reactor systems were suffering increasing technical problems due to ageing, requiring effective management. An example was that Tireless had had a small radioactive coolant leak for eight days in February 2013.

Potential export
In 1987, the Canadian White Paper on Defence recommended the purchase of 10 to 12 Rubis- or Trafalgar-class submarines under technology transfer. with the choice of the type of submarine due to be confirmed before Summer 1988. The goal was to build up a three-ocean navy and to assert Canadian sovereignty over Arctic waters. The purchase was finally abandoned in April 1989 and the Canadian Forces eventually acquired four of the Royal Navy's diesel-electric Upholder-class submarines.

The Trafalgar class is a refinement of the Swiftsure class and was designed six years later than its predecessor. The design includes a new reactor core and Type 2020 sonar (now replaced by Sonar 2076 on some boats). The internal layout is similar to the Swiftsure, and is only 2.5 metres longer. However at a dived displacement of 5,300 tonnes the Trafalgar class is significantly larger. Some major improvements over the Swiftsure class include several features to reduce underwater radiated noise. These comprise a new reactor system, a pumpjet propulsion system rather than a conventional propeller, and the hull being covered in anechoic tiles which are designed to absorb sound rather than reflect it, making the boats quieter and more difficult to detect with active sonar. Like all Royal Navy submarines, the Trafalgar class have strengthened fins and retractable hydroplanes, allowing them to surface through thick ice.

The Trafalgar class is equipped with 5 x 21-inch (533 mm) torpedo tubes with accommodation for a mixture of up-to 30 weapons:

* Tomahawk land-attack cruise missiles - range 1,240 miles (2,000 kilometres)
* Spearfish heavyweight torpedoes

The introduction of the 2076 towed array passive search sonar equipped on at least four boats of the Trafalgar class has significantly improved their capabilities. BAE claims that the 2076 represents a "step change" over previous sonars and is the world's most advanced and effective sonar system.

Trafalgar class

1. HMS Trafalgar (S107) Commissioned 1983. Decommissioned 2009.
2. HMS Turbulent (S87) Commissioned 1984. Decommissioned 2012.
3. HMS Tireless (S88) Commissioned 1985. Decommissioned 2014.
4. HMS Torbay (S90) Commissioned 1987. Decommissioned 14 July 2017.
5. HMS Trenchant (S91) Commissioned 1989. To be decommissioned 2019.
6. HMS Talent (S92) Commissioned 1990. To be decommissioned 2021.
7. HMS Triumph (S93) Commissioned 1991. To be decommissioned 2022.

Class and type: Nuclear-powered attack submarines
4,800 tonnes, surfaced
5,300 tonnes, submerged
Length: 85.4 m (280 ft)
Beam: 9.8 m (32 ft)
Draught: 9.5 m (31 ft)
1 × Rolls Royce PWR1 nuclear reactor
2 × GEC steam turbines
2 × WH Allen turbo generators; 3.2 MW
2 × Paxman diesel alternators 2,800 shp (2.1 MW)
1 × pump jet propulsor[Note 1]
1 × motor for emergency drive
1 × auxiliary retractable prop
Speed: Up to 32 knots (59 km/h), submerged
Range: Only limited by food and maintenance requirements.
Crew Complement: 130
Electronic warfare and decoys:
2 × SSE Mk8 launchers for Type 2066 and Type 2071 torpedo decoys
RESM Racal UAP passive intercept
SAWCS decoys carried from 2002
5 × 21-inch (533 mm) torpedo tubes with stowage for up to 30 weapons:
Tomahawk land-attack missiles
Spearfish heavyweight torpedoes

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 07 Jun 2015, 23:23
by SKB

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 04 Aug 2015, 09:31
by The Armchair Soldier
Two More Submarines to be Based at Faslane
Two of the Royal Navy’s Trafalgar Class nuclear powered but not nuclear armed submarines will be moved to the Clyde from Devonport, the Defence Secretary has confirmed. The moving of the hunter-killer fleet north is expected to bring an extra 1,500 jobs to the region.
Read More: ... d-faslane/

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 04 Aug 2015, 17:22
by Old RN
Small correction. The only Swiftsure class boat to have a conventional propeller was the first (HMS Swiftsure itself) all the rest had propulsor (pump-jet). IIRC this caused Swiftsure to have a slightly taller upper rudder than the rest of the class because of the torque from the propeller.

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 04 Aug 2015, 23:13
by seaspear
Is there the possibility that another reason to base them north, is to patrol areas the lack of air assets has shown in foreign submarine visits and by the time these vessels get decommissioned new patrol aircraft will be in place

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 19 Aug 2016, 21:54
by arfah

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 17 Sep 2016, 14:01
by GibMariner
HMS Triumph arrived at Gibraltar this morning:

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 01 Jan 2017, 10:11
by dmereifield
HMS Triumph tracked 2 Russian subs over the Christmas period using a new non-acoustic detection system. ... ael-Fallon

The article also includes the normal increased defence spending blah blah blah

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 01 Jan 2017, 10:54
by shark bait
Intriguing, what methods does that leave us?
  • Wake detection?
  • Magnetic detection?
  • Electromagnetic detection?
  • others?

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 01 Jan 2017, 10:56
by SKB
Did they follow a tug?! :twisted:

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 01 Jan 2017, 13:24
by Cooper
May just be mis information to make the Russians even more paranoid...if that's possible.

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 07:41
by rbw91
If it's been reported by The Express, it is safe to say it is probably bollocks.

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 08:27
by marktigger

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 09:12
by arfah

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 11:28
by Pseudo
arfah wrote:Magma displacement

:lol: Well played, Jonesy!

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 15:48
by shark bait
I've heard thermal mentioned quite a few times on forums, but nothing scientific, and I'm not convinced it's true.

Heat certainly won't radiate through water, and although a fast moving sub may be dumping a couple of megawatts of heat into the environment, that environment is so vast the effects will be very small and hidden within natural fluctuations.

Thermal detection refers to hot gas emitted from diesel subs, not nukes, which is detectable from aircraft.

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 16:16
by Timmymagic
shark bait wrote:I've heard thermal mentioned quite aap few times on forums, but nothing scientific, and I'm not convinced it's true.

Heat certainly won't radiate through water, and although a fast moving sub may be dumping a couple of megawatts of heat into the environment, that environment is so vast the effects will be very small and hidden within natural fluctuations.

About 15 years ago there was some talk about the French developing some form of submarine detection that could be deployed on satellites. The gist of it was that it involved some form of wake detection. especially given the type of satellites the French were operating/developing at the time. But given that the French have continued to build subs, as have the US and UK I think we can put it in the speculation drawer. The same as every Russian and Chinese radar making stealth obsolete whilst both the Chinese and Russians make every effort to develop stealth aircraft..

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 16:20
by shark bait
Wake detection is a real technique, the issue was the effects were small so it became easier to listen for subs, but now listening is becoming much more difficult wake detection is being revisited.

Looking at the table of wave heights it's only going to be feasible for fast and shallow subs. Like most things, it's another tool, along with others, but not a golden bullet.


Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 17:44
by ArmChairCivvy
Looks like there are at least 4 nations at it... the UK and Japan being the additions to the usual suspects: ... rines.html

Another source (Carlo Kopp) said this at the start of our decade (probably true, and specifically helping to keep known submarine bases under constant watch):
"become primarily a ‘tripwire’ sensor, not unlike
MAD used for initial detection and tracking rather
than prosecution of an attack.
Ultimately, once SAR wake detection technology
matures, it will provide a potent capability to detect
submarines from orbital and high flying airborne
platforms. This will drive submarines to greater
depths and lower transit speeds, and result in
further design changes in hull shaping to produce
the least detectable wake patterns."

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 19:01
by Ron5
Laser radar.

North Sea too shallow and too busy for wake detection to be worth a darn.

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 19:27
by bobp
Like SB above I have heard of thermal. If a satellite can detect changes in temperature as in global warming, then it can detect the reactor cooling water discharge of a nuclear reactor. However don't think this applies to the mysterious antenna spotted on the sub.

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 02 Jan 2017, 20:00
by shark bait
A satellite couldn't detect it, by the time the hot water has mixed in the wake, and risen to the surface the difference will be negligible. The effect would be less than you pouring a kettle into a pond and asking a satellite to pick it up.

I wouldn't be so quick to dismiss wake homing, there isn't much patroling underwater anywhere in the world.

If the article is right, the tech could be wake homing. The Russians supposedly use wake homing techniques, which uses a bunch of upward looking sensors on the hull, which look a bit like these supposed antenna.

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 07 Jan 2017, 20:29
by shark bait
HMS Triumph deployed on an operational patrol two months ago.
Skippered by Commander David Filtness, one of the Royal Navy’s most able submarine captains, it was tasked to make a sweep of the UK coastline and fitted with the top-secret non-acoustic detection tracking system.

And its new equipment does not rely on sonar. Working alongside the submarine’s advanced sonar 2076 system which plots noise, it is completely silent , giving the Royal Navy’s hunter-killer fleet the fleet a crucial advantage.

Instead, it monitoring sea patterns at depth and identifies movement created by big submarines, which can then be investigated by teams of specialists. ... ys-fallon/

Can't comment on the validity of the post, but sounds like wake detection.

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 12 Feb 2017, 00:31
by dmereifield
It's only the Daily Express.....but..... ... ck-reactor

Re: Trafalgar Class Attack Submarine (SSN) (RN)

Posted: 12 Feb 2017, 04:09
by ArmChairCivvy
Well, some folks around these pages may remember how I was writing about a plan to "go faster" with the switch in reactor type (but in the end, all of the A-boats will be finished with the old type "inside"... and perhaps with "Intel inside" but running Windows for Submarines - anyone interested can check which version of Windows that was built on).

From the linked article above
"In 2013 a Ministry of Defence report revealed two Trafalgar class boats had been operating with a safety defect which put the vessels and crew at “serious” potential risk."

And what did SJP say... old types are extended beyond their meaningful service lives, at a very high cost, cfr. this bit in the above linked article
"The Trafalgar submarines have had their service extended by 10 years due to ongoing delays in the construction and delivery of the new Astute class. But of Britain’s three Astutes, two are undergoing trials while the third is being repaired after a collision in Gibraltar."
- the "go-slow" decision with A-boats - to make the work last until the Dreadnoughts would be started, by dropping one boat from the schedule - and adding a bn in costs, for nothing, will now come back to bite, with a vengeance!

A feast for the journos...