Type 23 Duke Class Frigate

In February 1996 Yarrow Shipbuilders Ltd, now BAE Systems, won a contract to build three Type 23 Duke Class frigates for




Swan Hunter and BAE Systems


Royal Navy and Chilean Navy




Type 23 Duke Class frigate

The Type 23 Duke Class frigate was originally designed for anti-submarine warfare (ASW), but the addition of the vertical-launched Seawolf point missile defence system and the Boeing Harpoon surface-to-surface missile, has expanded its role to include anti-surface warfare (ASuW).

The first Type 23 was commissioned in 1990. TheType 23 Duke Class frigates are:

  • HMS Norfolk (F230) commissioned June 1990
  • HMS Argyle (F231) commissioned May 1991
  • HMS Lancaster (F229) commissioned May 1992
  • HMS Marlborough (F233) commissioned June 1991
  • HMS Iron Duke (F234) commissioned May 1993
  • HMS Monmouth (F235) commissioned September 1993
  • HMS Montrose (F236) commissioned June 1994
  • HMS Westminister (F237) commissioned May 1994
  • HMS Northumberland (F238) commissioned November 1994
  • HMS Richmond (F239) commissioned June 1995
  • HMS Somerset (F82) commissioned September 1996
  • HMS Grafton (F80) commissioned May 1997
  • HMS Sutherland (F81) commissioned July 1997
  • HMS Kent (F78) commissioned June 2000
  • HMS Portland (F79) commissioned May 2001
  • HMS St Albans (F83) commissioned June 2002

In July 2004, the UK Ministry of Defence announced that the Type 23 fleet was to be reduced to 13. Batch 1 vessels, HMS Norfolk, and Marlborough were decommissioned in 2005 and Grafton in March 2006. All three were sold to the Chilean Navy and delivered over 2007-2008. Grafton was renamed Almirante Lynch (FF-07), Marlborough to Almirante Condell (FF-06) and Norfolk to Almirante Cochrane (FF-05).

Type 23 Duke Class frigate deployments

In July 2006, HMS St Albans assisted in the evacuation of UK nationals from Beirut during the Israel / Lebanon conflict, as part of the Royal Navy Operation Highbrow.

In late July, 2011 British Royal Navy Frigate Type 23 Duke-class HMS Sutherland conducted a boarding operation in international waters close to Libya. This operation was to prevent the flow of illegal weapons into the hands of pro-Gaddafi forces to protect Libyan civilians.

“The Type 23 frigates were originally designed for anti-submarine warfare.”

Type 23 command and control

The surface ship command system (SSCS) has been developed by BAE Systems.

It is a fully distributed Ada system based on SUCCESSOR technology using Intel 80486 processors, INMOS T800 transputers and a dual fibre-optic network.

The SSCS has been upgraded to integrate the new Sonar 2087 and Outfit DLH decoy system. The satellite communications system is the Astrium (formerly Matra Marconi) SCOT 1D.

SSCS weapons

The ships are armed with eight Harpoon surface-to-surface missiles in two four-cell launchers and vertical-launch Seawolf (GWS 26 Mod 1 VLS). Harpoon is a medium-range (90km) anti-ship missile using inertial and active radar guidance. VLS Seawolf is a surface-to-air missile with command to line of sight (CLOS) guidance and radar and electro-optic tracking. It has a range of 6km.

The missile division of Alenia Marconi Systems (now part of MBDA) was awarded a contract for the mid-life update of the Seawolf missile which will include upgrading the radar tracking system and addition of infrared tracking, with sensor fusion technology. The new Seawolf block 2 missile entered service in July 2005.

Improvements include a new electronic fin actuation system for improved control and extended range and a new fuse with IR/RF (infrared / radio frequency) sensors for improved performance against very low sea-skimming targets.

“The ships are armed with eight Harpoon surface-to-surface missiles in two four-cell launchers and vertical-launch Seawolf.”

The frigates were originally equipped with a BAE Systems RO Defence 114mm mk8 mod 0 gun with a range of 22km against surface and 6km against airborne targets. These have been being replaced with the electrically driven mk8 mod 1. In 2001, HMS Norfolk was the first ship to be fitted with the new gun.

Both mod 0 and mod 1 guns have the capability to fire the new high-explosive extended-range ammunition developed by RO Defence, which extends the surface range to 27km. HMS Richmond was the first RN vessel to receive the HE ER round in April 2004.

The fire control system for the 114mm gun is the BAE Systems Sea Archer 30 (GSA 8) electro-optical fire control system.

There are also two BAE Systems / Oerlikon 30mm guns with range of 10km against surface and 3.5km against airborne targets. These have been replaced with MSI Defence Systems DS30 mk2 automatic 30mm guns, under a contract placed in September 2005.

The DS30 mk2 comprises an upgrade mount, ATK Bushmaster II cannon and an electro-optic fire control system. HMS Somerset was the first vessel to receive the new gun in 2007 and deliveries are to complete in 2014.

The ships have four 324mm torpedo tubes carrying BAE Systems Stingray lightweight torpedoes. Stingray has depth 750m and range 11km. A contract for the upgrading of the Stingray to Mod 1 standard was awarded to BAE Systems in February 2003. The upgrade includes new digital homing, guidance and control systems. The first 100 were delivered in June 2006. In September 2011, the Royal Navy decided to install its new radar ARTISAN to the Type-23 frigate HMS Iron Duke. It is scheduled to start during a refit operation in mid-2012.

Type 23 Frigate helicopters

The Type 23 Frigates HMS Argyle, Sutherland, Montrose, Saint Albans, Iron Duke, Kent, Portland, Somerset and Grafton carry Lynx MK8 helicopters, whereas HMS Lancaster, Monmouth, Westminister and Northumberland carry Merlin MK1 helicopters. The naval Super Lynx is a anti-surface warfare, anti-submarine warfare, search and rescue, and utility operational aircraft. Merlin HM MK1 is an Anti-Submarine (ASW) variant of the EH101 helicopter. The aircraft has an excellent integrated mission system, which can process data from on-board sensors, giving Merlin good capability to search, locate and attack submarine targets.

Countermeasures – Sea Gnat (Outfit DLB) decoys

Countermeasures systems include four Sea Gnat (Outfit DLB) decoys and a Type 182 towed torpedo decoy. The Sea Gnats are mounted on Hunting Engineering 130mm six-barrel launchers. Type 23 frigates are fitted with the BAE Systems Outfit DLH upgrade which will allow the launch of the Siren Mk 251 active decoy round as well as the Sea Gnat. Siren entered service with the Royal Navy in January 2004.

Thales Defence UAF-1 ESM is fitted to the first seven ships and Thales Defence’s UAT(1) to the rest. Thales Defence’s Scorpion jammer is also fitted.

The Duke Class is fitted with the Type 2070 towed torpedo decoy system. This is being replaced with the Ultra Electronics surface ship torpedo defence (SSTD) system. HMS Westminster was the first vessel to receive the system, followed by HMS St Albans in June 2008.


Radar systems include: BAE Systems Type 996 (AWS-9) E/F band 3D search radar, Kelvin Hughes Type 1007 I-band navigation radar and two BAE Systems Type 911 fire control radars associated with the Seawolf missile system. Type 911 is a dual band, I-band 8GHz to 10GHz and L/M-band 40GHz to 100GHz, fully automatic radar.

The Type 996 radar is to be replaced by a new medium-range radar. In March 2007, the UK MoD issued invitations to tender for the radar. Bids have been received by BAE Systems Insyte (Artisan 3D E/F-band radar), Elta Systems (EL/M-2238 STAR E/F-band) and Thales Naval UK (SMART-S mk2 E/F-band). In August 2008, BAE Systems Insyte (with Qinetiq) ARTISAN 3D E/F-band radar was selected for the MRR and the system is planned for installation in mid 2012. HMS Richmond has started a £20m upgrade. Upgrades include Sea Wolf, better command and weapons control systems, and 30mm automatic guns with increased accuracy and range.

“The frigates have four 324mm torpedo tubes carrying BAE Systems Stingray lightweight torpedoes.”

Type 23s have Thales Underwater Systems (formerly Thomson Marconi Sonar) Type 2050 medium-range bow-mounted active / passive search and attack sonar and Ultra Electronics (formerly Dowty) Type 2031Z very low-frequency passive search towed array sonar.

However, the latter is being replaced by the Thales Underwater Systems Type 2087 low-frequency active sonar (LFAS). This is a variable-depth low-frequency transmitter and a passive, towed reception array.

The Type 2087, which entered service in February 2006, has a greater range with bistatic and intercept capability.

The system is operated from DRS Technologies OPUS2 multi-function consoles. HMS Westminster, HMS Northumberland, HMS Richmond and HMS St Albans have been fitted with the new sonar.

A number of Type 23 frigates are now fitted with the SELEX Sensors and Airborne Systems Sigma Caveo thermal imaging camera.

CODLAG propulsion

The frigates are powered by a diesel-electric and gas (CODLAG) system, which consists of two Rolls Royce Spey SM1A 34,000hp gas turbines and two Alstom 1.5MW 4,400hp electric motors. There are also four Alstom 12 RP2000CZ 1.3MW 7,000hp auxiliary diesels. Using the diesel-electric motors, the economical speed is 15kt and the range is 7,800 miles. Maximum speed is 28kt.

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