Astute Class SSN Submarine – Royal Navy

The Royal Navy’s Astute Class submarine is a nuclear-powered attack submarine which will replace the five Swiftsure Class submarines, launched between 1973 and 1977 and approaching the end of their operational life.

HMS Sceptre Swiftsure Class submarinesSwiftsure Class submarines

The initial order quantity was three, but the UK MoD has ordered an additional four, meaning seven submarines will be built as part of the Astute Class. The performance specification of the Astute is an extension of the performance of the Trafalgar Class batch 1 fleet of the Royal Navy’s Second Submarine Squadron, based at Devonport.

Trafalgar ClassTrafalgar Class 3D model

The Trafalgar batch 1 submarines are to be decommissioned by 2022, beginning with HMS Trafalgar, which was decommissioned in December 2009. The Astute Class submarines will be based at Faslane in Scotland.

HMS Astute arrives at its base at Faslane, Scotland, in 2009

Royal Navy’s attack submarine development history

BAE Systems Astute Class is the prime contractor for the project and the submarines are being built at the BAE Systems Marine Barrow shipyard. The first three Astute ships were named HMS Astute (S119), HMS Ambush (S120) and HMS Artful (S121).

The fourth submarine was named HMS Audacious (S122). The fifth Astute Class submarine was named HMS Anson (S123) in September 2011. The sixth and seventh will be named as HMS Agamemnon (S124) and HMS Ajax (S125) respectively.

Astute Class submarine Pre-launch

The keel for the first-of-class HMS Astute was laid in January 2001 and it was launched on 8 June 2007. In October 2007, HMS Astute made her first dive, for an underwater systems test, at the ‘dive hole’ in Devonshire Dock, Barrow. Also, in October, the vessel successfully carried out first firing trials from its torpedo tubes. HMS Astute was commissioned in August 2010.

Astute Class

The keel of HMS Ambush was laid in October 2003. It was launched in December 2010. Ambush made its first voyage in January 2011. The initial dive test of the Ambush was completed in September 2011. The Ambush was commissioned in March 2013. The HMS Astute and HMS Ambush submarines were handed over to the Royal Navy in July 2013.

The keel of HMS Artful was laid in March 2005. The submarine was launched in May 2014 and performed maiden dive in October 2014. It is expected to be commissioned by 2015.

Astute Class

In May 2007, the UK MoD awarded BAE Systems a contract to build a fourth Astute Class submarine, HMS Audacious (S122), to enter service in 2018. The keel of Audacious was laid in March 2009. In December 2012, BAE Systems received £1.2bn contract from the UK MoD for the design, construction, test and commissioning programme of Audacious.

<br/><a href="" target="_blank">View Raw Image</a>Astute Class

The fifth and sixth Astute Class submarines, HMS Anson (S123) and HMS Agamemnon (S124), were ordered in March 2010. The keel for Anson was laid in October 2011 while that of Agamemnon was laid in July 2013. These submarines are expected to be commissioned in 2020 and 2022 respectively. The seventh, HMS Ajax (S125), has been confirmed but the order is yet to be placed.

Command and control systems on Astute Class submarines

Astute combat management system (ACMS) is being supplied by BAE Systems Insyte (formerly Alenia Marconi Systems) and is a development of the submarine command system (SMCS) currently in service in all classes of UK submarines.

Astute Command and control room @defenseindustrydaily.comAstute Class Submarine Cutaway – Midships


45 – Port Side Communications Office

60 – Control Room Consoles

62 – Senior Ratings Bunks

58 – Senior Ratings Bathrooms

ACMS receives data from the sonars and other sensors and, through advanced algorithms and data handling, displays real time images on the command consoles. Factory acceptance of the operational software was received from the Astute Prime Contract Office in July 2002.

The control room, in which up to 15 crew work. The planesman steers and dives the sub from here Greg White Leading engineering technician Andrew Gee tests out the sub’s steering system in the control room HMS Ambush

EADS Defence & Security Systems and EADS Hagenuk Marinekommunikation were awarded the contract to provide the external communications systems for the Astute in August 2005. Strachan and Henshaw are to provide the weapon handling and launch system (WHLS).

HMS Astute, Sonar screens: Astute Command and control room

Northrop Grumman Sperry Marine was selected in March 2008 to provide the platform management system for the fourth of class, HMS Audacious.

HMS Artful uses new “brain” to fire torpedo: Here

Astute Class Tomahawk missiles and torpedoes

Astute is equipped with the Tomahawk Block IV (tactical tomahawk) cruise missile from Raytheon, fired from the 533mm torpedo tubes.

Astute bow section @forumimage.ruTomahawk Block IV (tactical tomahawk) cruise missile from Raytheon

Tomahawk is equipped with the TERCOM terrain contour mapping-assisted inertial navigation system. The terrain contour mapping for use over land combines onboard radar altimeter measurements with terrain mapping data installed in the missile. Block II added digital scene matching area correlation (DSMAC) guidance.

Inside: The weapons room of the £1billion sub. Many details of her weapons system remain top secret

Block III improvements include an improved propulsion system and Navstar global positioning system (GPS) guidance capability. The GPS provides location and velocity data of the missile for precision targeting.

The TERCOM radar uses a stored map reference to compare with the actual terrain to determine the missile’s position

The Tomahawk land-attack cruise missile has been used to attack a variety of fixed targets, including air defense and communications sites, often in high-threat environments. The land attack version of Tomahawk has inertial and terrain contour matching (TERCOM) radar guidance. The TERCOM radar uses a stored map reference to compare with the actual terrain to determine the missile’s position. If necessary, a course correction is then made to place the missile on course to the target. Terminal guidance in the target area is provided by the optical Digital Scene Matching Area Correlation (DSMAC) system, which compares a stored image of target with the actual target image.

(GPS) guidance capability

Tomahawk has a range of up to 1,000 miles and a maximum velocity of 550mph. Block IV includes a two-way satellite link that allows reprogramming of the missile in flight and transmission of battle damage indication (BDI) imagery. Tomahawk Land Attack Missile (TLAM) Block IV entered service with the UK Royal Navy in April 2008, onboard Trafalgar batch I submarine, HMS Torbay.

BGM-109 Tomahawk

Astute has six 533mm torpedo tubes, and is equipped with Spearfish torpedoes and mines. There is capacity for a total of 36 torpedoes and missiles.


Spearfish torpedoe

Spearfish Heavyweight Torpedo

The Spearfish advanced heavy weight torpedo from BAE Systems is effective against submarine and surface threats in oceanic and coastal waters. The 1.85t torpedo is in service with the submarine fleet of the UK Royal Navy.

The Spearfish carries Aluminised PBX explosive warhead of 300kg and is directed towards the target by high-capacity guide wire system and passive and active sonar.

Its power plant is composed of a gas turbine engine using Otto Fuel as a liquid monopropellant, and Hydroxyl Ammonium Perchlorate (HAP) as oxidant. The propulsion system allows the Spearfish to engage targets within 48km at low speed.

PHOTO_Space%20Systems_14%20Spearfish%20EngineSpearfish Heavyweight Torpedo power plant

The Spearfish torpedo from BAE Systems is wire-guided with an active / passive homing head. The range is 65km at 60kt. Spearfish is fitted with a directed-energy warhead.

Countermeasure technology and sensors

The countermeasures suite includes decoys and electronic support measures (ESM). The ESM system is the Thales Sensors Outfit UAP(4). Outfit UAP(4) has two multifunction antenna arrays, which are mounted on the two non-hull penetrating optronics masts from Thales (formerly Pilkington) Optronics and McTaggart Scott.

Astute Class submarines are fitted with the Royal Navy’s new Eddystone Communications band Electronic Support Measures (CESM) system, also fitted to the Trafalgar Class submarines. The Eddystone system was developed by DML of Devonport UK, with Argon ST of the US.

It provides advanced communications, signal intercept, recognition, direction-finding and monitoring capabilities. Sea trials of the system were completed in December 2007.

The immediate future of Thales Underwater Systems’ Sonar 2076 appears solely linked the U.K. Royal Navy’s Astute-class submarine. The Sonar 2076, or Type 2076, is a fully integrated passive/active search-and-attack sonar suite installed on the Astute class and as part of the midlife update of Trafalgar class submarines. A total of four Sonar 2076 systems have reportedly been produced for Trafalgar class submarines, and seven have been ordered for the first batch of Astute class submarines.

The Royal Navy’s planned inventory for a nuclear submarine fleet is eight boats: seven Astute class and one Trafalgar class. However, by the time the seventh and final Astute boat is commissioned, the remaining Trafalgar class boat will be long overdue for replacement.

It is still unclear whether the last of the Trafalgar class submarines will be retired without replacement, replaced by an eighth Astute-class submarine, or replaced by the lead ship in a new class of nuclear submarine.

Astute is fitted with I-band navigation radars. The sonar is the Thales Underwater Systems (formerly Thomson Marconi Sonar) 2076 integrated passive / active search and attack sonar suite with bow, intercept, flank and towed arrays. Sonar 2076 has so far been fitted to Trafalgar Class submarines Torbay, Trenchant and Talent, entering service in February 2003. Astute is fitted with the latest version of the Thales S2076 integrated sonar suite.

Atlas Hydrographic provided the DESO 25 high-precision echosounder, which are fitted on the Astute. DESO 25 is capable of precise depth measurements down to 10,000m.

CM010 optronic masts

Astute has two non-hull-penetrating CM010 optronic masts developed by Thales Optronics. McTaggart Scott supplied the masts. The CM010 mast includes thermal imaging, low light TV and colour CCD TV sensors.

CM010 optronic mastsCM010 optronic masts

The optronic masts, which will be powered by Wind River VxWorks’ mission-critical real-time operating system, are the result of a ten year, multi-million pound program, and will be installed in the Royal Navy’s Astute-class submarines.

Traditional submarines are vulnerable to detection when the periscope is used – however, the optronic mast uses a non-hull breaching design, in which the Sensor Head Unit extends from the submarine fin and rapidly captures a 360 degree scan, sending the image to the console screens in the sub’s operation center. The image can be then be analyzed at the leisure of the commander, with a reduced risk of detection. The optronics masts also incorporate multi-function antenna arrays, which monitor the radar environment, provide command and situational awareness of other radar equipped platforms, and enable a submarine to take early evasive action.

The Wind River VxWorks mission-critical real-time operating system runs on Thales’ quad PowerPC AltiVec COTS boards and AdaCore GNAT Pro. It powers the stabilization system, a high-performance 3 axis to sub-pixel accuracies; video and thermal camera control; communication with the in-hull systems; and the mechanisms and motors in the SHU. The SHU is a pressure proof, electro-optical assembly that contains high-performance cameras, optics, environmental sensors and stabilization mechanisms. It is can function in temperatures ranging from -15 degrees Celsius to 60 degrees Celsius, and can withstand a nearby explosion.

RemoteReality day/night 360-degree advanced periscope camera system

The Mast Control Unit uses two processors to control the mast raising equipment, control the stabilization system, and communicate with the submarine’s tactical, data and combat systems. The stabilization system is designed to compensate for the movement of the sub and the water, providing a clear image for analysis.

In addition to being used in the Royal Navy, the optronic mast technology is also being used by the Japanese Maritime Self-Defense Force.

Raytheon Systems was contracted to provide the Successor IFF (identification friend or foe) naval transponder system for the Astute Class.

Propulsion, power and speed of the UK’s nuclear submarines

The nuclear power is provided by the Rolls-Royce PWR 2 pressurised water reactor. The long-life core fitted on the PWR 2 means refuelling will not be necessary in the service life of the submarine.

Astute Class submarine

The other main items of machinery are two Alstom turbines and a single shaft with a Rolls-Royce pump jet propulsor, consisting of moving rotor blades within a fixed duct.

UK Nuclear Sub LayoutUK nuclear submarine layout

There are two diesel alternators, one emergency drive motor and one auxiliary retractable propeller. CAE Electronics provided the digital, integrated controls and instrumentation system for steering, diving, depth control and platform management.

The PWR 2 second-generation nuclear reactor was developed for the Vanguard Class Trident submarines. Current generations of PWR would allow submarines to circumnavigate the world about 20 times, whereas the latest development of PWR would allow circumnavigation 40 times without refuelling.

The major equipment components in the development of PWR 2 were the reactor pressure vessels from Babcock Energy, main coolant pumps from GEC and from Weir and protection and control instrumentation from Siemens Plessey and Thorn Automation.

A dummy Cruise missile inside Astute @BBC UKFeeding the crew: The submarine’s kitchen will be staffed by five chefs providing food 24-hours a day for her officers and crew HMS Ambush @vpinternational.caThe crew’s quarter (left) – there are a maximum of 22 bunks per cabin, each man has a bunk, a locker and a curtain. The only man to have his own cabin the captain, Cmdr Peter Green (right), pictured on his seat in the control room.
Entered service


Crew 98 + 12 men
Diving depth (operational) over 150 m
Diving depth (maximum) over 300 m
Sea endurance 90 days
Dimensions and displacement
Length 97 m
Beam 10.7 m
Draught 10 m
Surfaced displacement 6 500 tons
Submerged displacement 7 200 tons
Propulsion and speed
Surfaced speed ?
Submerged speed 29 knots
Nuclear reactors 2 x Rolls-Royce PWR2
Steam turbines 1 x ?
Missiles Tomahawk cruise missiles; Harpoon anti-ship missiles in place of torpedoes
Torpedoes 6 x 533-mm bow tubes for 36 Spearfish torpedoes
Other mines in place of torpedoes

Source: the net


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