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Type 23 Duke Class Frigate

The Type 23 Frigate was designed to replace the LEANDER Class and Type 21 Frigates. The original requirement (from 1983) was for a ship capable of operating in the North Atlantic, with a primary role of Anti-Submarine Warfare (ASW), as well as some general purpose capability for operations inside and outside the NATO area. Among its capabilities, the Type 23 would deploy a towed array sonar system, and the Future Medium Helicopter (now Merlin). The design incorporated the lessons from the Falklands campaign; among the areas of particular concern were the ships' survivability and their ability to defend themselves in combat, as well as incorporating design features to make it a genuinely 'stealthy' vessel. The class has been flexible enough to adapt to changing strategic circumstances, and has evolved into a capable general purpose frigate, while retaining its ASW specialisation. We are unable to provide statistical data on planned and actual usage.

The planned service life when Type 23s entered service was 18 years, which by 2007 had since been extended to 28 years.

The type 23 class frigate was conceived in the late 1970s as a light anti-submarine frigate whose primary role was to meet the then Soviet nuclear submarine threat in the North Atlantic. This new class was intended to replace the Leander class frigate, which was developed in the 1950s and the type 21 class frigate, developed in the 1960s, as the backbone of the Royal Navy's surface ship anti-submarine force. The type 23 class frigate was not procured as a replacement for the type 22 frigate.

As one of the primary workhorses of the Fleet, Type 23s spend much of their time at sea on operational taskings worldwide. Powerful and versatile with the capability to operate anywhere in the world, the type 23 frigate is the mainstay of the modern surface fleet. The 13 Type 23 frigates form 50% of the total frigate/destroyer force in the Royal Navy. Originally designed for the principal task of anti-submarine warfare, they have evolved into powerful and versatile multi purpose ships with the capability to operate anywhere in the world. The effectiveness of these ships is enhanced by their stealth design, which reduces their radar signature significantly. In addition to the war fighting roles described above, the ship is trained to conduct a wide range of other tasks. These include embargo operations using boarding teams inserted from the ship's boats or helicopter, disaster relief work and surveillance operations.

The requirements for a low noise signature and high endurance led to the adoption of a new type of propulsion system. The propulsion plant of Type 23 is CODLAG [Combined Diesel Electric and Gas Turbine, also known as CODEAG] type with each two of Spey gas turbines and electric motor powered by diesel generators. The primary role of the Royal Navy's Type 23 frigate -- the Norfolk class -- is antisubmarine operations with a towed sonar array. This aggravated the problem of widely divergent maximum and cruise power requirements, and largely influenced the choice of propulsion machinery, part of which includes the first electric drive that the RN has used in a major surface-ship since the 1920s. The class has a CODLAG installation with twin f.p. propellers. There are two Spey gas-turbines, a type capable of producing up to 14 MW, for the frigate's high-speed operation. SSS clutches are incorporated in an arrangement that allows the reduction gearing to be stopped under silent running' conditions.

The very high combined electrical load for ship's services and, during operation at the lower speeds and manoeuvring, for propulsion is met by an integrated system with four GEC Paxman Valenta Diesels as prime movers; primary power generation is at 600 V, with ship's service supply reduced to 440 V and isolated from the supply to the d.c. low-speed propulsion motors by the use of motor-generators. Vosper Thornycroft are supplying a fully-digital control and surveillance system. Overall coordination of the machinery arrangements is the responsibility of Yarrow Shipbuilders, the lead yard for the class. The reason for choosing this system, and its components, in preference to alternatives, was to meet requirements that include low cruise-power, high maximum power, fuel economy, manoeuvrability, and low underwater noise-levels.

The Ship's weapons include the Harpoon long-range surface to surface homing missile, two 30mm close range guns and the versatile 4.5 Mk 8 gun. For self-protection against any incoming air threat there is the Vertical Launch Seawolf Missile System. This comprises two tracking radars, one forward and one aft, and a silo containing thirty-two missiles. The Ship also boasts a Magazine Torpedo Launch System which allows the launch of torpedoes from four torpedo tubes built into both sides of the hanger superstructure. As with the fixed Seawolf silos, this arrangement dramatically reduces the exposure of personnel on the upper deck in action by obviating the need to reload torpedo tubes or missile launchers.

Among the sensor systems are a hull mounted sonar, air surveillance radar type 996 and a sophisticated electronic warfare system, UAT, which passively monitors and recognises the electronic emissions of potential enemy ships and aircraft. At the heart of these systems is an advanced computer based command system connected to the combat system highway. This data highway enables the computer to communicate with and control the weapon systems; it also allows any weapon or sensor system to communicate directly with any other, without going via the central command system.

When required, the Ship's weapon systems can be brought to bear by the above water weapons team, and if threatened, the Ship can defend herself against aircraft through the high-speed vertical launched Sea Wolf system, 30mm cannons and machine guns. Against a surface threat, Harpoon anti ship missiles can engage targets lying far beyond the visible horizon, while the 4.5-inch gun is utilised closer in. The 4.5-inch gun is also an effective means of providing lethal, accurate fire support to troops ashore during joint operations. Finally, the helicopter's Sea Skua missiles give Type 23 Frigate the ability to engage surface targets at arm's length; particularly effective against small patrol boats operated by many countries around the globe.

When first commissioned the complement of crew carried by Type 23 frigates was 173. The complement as of 1998 was 171. At that time there were no plans to reduce the complement of Type 23 frigates by refitting with less manpower-intensive equipment. Manning implications are taken into consideration when the Operational Requirement for future ships is considered; however, the size of the complement is affected by other considerations such as the manpower needed for damage control and fire-fighting. On the type 22, the three batches have different complements, but they range between 224 per ship and 273. The type 23, depending on which book one reads, has between 157 and 173, so the complement of a type 23 is about four fifths the complement of a type 22, although they do the same job. In a way, that is good, because it means that the ship can be smaller, so it can be built for less money, it uses less fuel and less materiel, and one is paying fewer sailors.

The Type 23 Frigate was designed with the expectation of spending a high proportion of its operational time in the demanding and stressing environment of the North Atlantic. The nature of the threat has evolved with resultant changes to operational priorities and deployments, the consequence of which is that these ships spend less time in the North Atlantic. An opportunity has therefore arisen to extend the interval between major maintenance periods. Improved processes for the specification and management of equipment maintenance are also being introduced. The collective effect of these developments is to increase the availability of Type 23 Frigate capability for operations. Type 23 frigates achieved approximately 85-89 percent average availability for operational service in each of the five years 1993-1998 with the exception of 1996 when the figure dropped to just over 80 percent due to a number of ships experiencing a particular defect. This discounts time spent in planned maintenance.

The actual cost per annum of operation for ships such as Type 23 frigates, Type 22 frigates, SSNs, Hunt Class minehunters and Sandown Class minehunters will vary considerably dependent on the tasking/maintenance undertaken. Indicative annual costs, including manpower, fuel and stores only, would be in the region of £16 million for a Type 23 and a Type 22 frigate, £11 million for an SSN, £3 million for a Hunt Class minehunter and £2 million for a Sandown Class minehunter.

In 1989 competitive bids were sought from British shipyards for a batch of between one and four type 23s. Three yards--Cammell Laird Shipbuilders in Birkenhead, Swan Hunter Shipbuilders in Newcastle upon Tyne and Yarrow Shipbuilders in Glasgow--responded, and it was an extremely keen and commercial competition, to the taxpayer's benefit. The competition demonstrated that the commercial approach was continuing to encourage improved efficiency in the industry, enabling it to compete more effectively here and abroad. It also underlined the benefit of ordering in batches and the better value for money that results from it. In December 1989, having invited tenders for up to four ships, Government decided to order three. To order four now, even all from one yard, would not give significantly more attractive unit prices than ordering three. The new ships were named Westminster, Northumberland and Richmond.

After evaluation of the bids, the Navy decided, subject to contract, to place the order with Swan Hunter Shipbuilders of Wallsend in Newcastle upon Tyne. Swan Hunter's won our order fairly and squarely on commercial terms. The value of the order was commercially confidential, the average unit cost of the three new ships was significantly less in real terms than for the last order, which in its turn was lower than for previous ships of the class. It follows that both Swan's and the other yards were extremely competitive this time. Nine type 23s were on order for the Royal Navy. It remained the Government's policy to maintain a surface escort fleet of about 50 destroyers and frigates. This latest order demonstrated as clearly as possible the commitment to NATO and to the nation's defence.

HM Ships Norfolk, Grafton and Marlborough were declared surplus to the Royal Navy's requirements in 2004 following a review of assets against operational demands. Under the 2005 agreement, BAE Systems was appointed as the Prime Contractor to carry out a major program of refurbishment and reactivation work to equip the ships to the Chilean Navy's exact requirements. The £134 million pound sales agreement arranged by the MOD's Disposal Services Authority (DSA) and signed in September 2005.

The former HMS Norfolk and former HMS Grafton, handed over to the Chilean Navy in November 2006 and March 2007 respectively. The 2003 defence cuts committed HMS MARLBOROUGH to pay off by March 2006. In June 2005, it was announced that HMS MARLBOROUGH would be sold to the Chilean Navy. Chile officially welcomed the Almirante Condell (the former-HMS Marlborough) into the Chilean fleet at a Commissioning Ceremony yesterday, Wednesday 28 May 2008. The former HMS Marlborough was re-named the Almirante Condell and the Director General of Procurement, Vice-Admiral Cristian Jantes, officially invested her new commanding officer, Captain Jorge Cruz at Her Majesty's Naval Base, Portsmouth. The vessel is the last of three former Royal Navy Type-23 frigates to be handed over to Chile.

Naval authorities have continually extended the lifespans of the UK’s ‘Duke Class’ Type-23 destroyers. First commissioned in 1989, the warships had a planned 18-years long lifespan, yet the ongoing extensions mean that the ships are slowly withering, and needing to spend much more time at the dock for heavy maintenance. HMS Monmouth, laid up in Devonport since 2019 was officially withdrawn from RN service on 30 June 2021 (without formal decommissioning ceremony). The ship would be towed to Portsmouth to be handed over to DRSO, prior to scrapping.

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Page last modified: 13-09-2021 13:48:45 ZULU