The move towards corvettes and frigates: in defence, as in life, fashions change. In the world's navies the fashion some 20 to 30 years ago leaned toward small, high-speed vessels with surface-to-surface missiles--these were known as fast attack craft. Operational experience has since driven more recent requirements towards larger ships of corvette or even frigate size.

The distinction between corvettes and frigates is extremely blurred and is not helped by references to 'light frigates'. Parameters of length and displacement help definition but are not absolutes; in two of the world's major reference works, Jane's Fighting Ships and the US Naval Institute's Combat Fleets of the World, the corvette tends to be a vessel between 55 and 85 metres with a 1300 to 5000-tonne displacement. The frigate is seen as between 86 and 140 metres in length with a displacement of between 1300 to 5000 tonnes. But these are not hard and fast rules; in corvettes the Indonesian Sigma class being built by Royal Schelde are 90 metres long and have a displacement of 1700 tonnes, the Russian Almaz Design Bureau Scorpion (Project 12300) class will have a displacement of 470 tonnes but will be 56 metres long while Brazil's Barrosso class is a 103-metre, 2350-tonne ship.

Both types of ship tend to be multirole escort vessels with a surface-to-surface missile system and a medium calibre (57 to 76 mm) gun as well as self-defence weapons. Corvettes tend to be shorter-ranged vessels designed to operate in coastal waters, often under the shield of land-based air power, which means they rarely require anything more than a self-defence anti-air warfare capability. Frigates tend to be deployed into blue waters to protect maritime lines of communication and usually will have some form of area air defence system and often, an anti-submarine warfare capability in the form of sonar and a flight deck with a hanger for a lightweight (four- to six-tonne) helicopter.

The move towards corvettes and frigates has been driven by two factors:

* for small navies previously using fast attack craft as the keel of their capability, personal experience and the lessons of the first Gulf War have demonstrated the limitations of these small, but powerful warships. Because of their size--up to 55 metres long and 489 tons displacement--their sensor range and self-defence capabilities were extremely limited as was their capacity to absorb battle damage. This was confirmed when most of the Iraqi strike force was annihilated by Coalition air power, including Lynx helicopters with Sea Skua missiles.

* a larger warship means that the radar antenna is higher, extending sensor range, while the defensive capability can be improved in terms of air defence weapons and compartmentalisation. Yet the versatility of corvettes and the lower costs of acquisition mean that some of the larger navies have become interested in them as a cheaper means of deploying a presence in low-risk theatres. The Royal Navy, for example, is considering a frigate/corvette mix to meet its Future Surface Combatant (FSC) requirement from 2015 to 2020 while Germany's only active surface programme is for the K-130 class, which were ordered in 2001.

Frigates have been the backbone of navies in the past 60 years. They can be deployed worldwide and can conduct a wide range of missions making them vital jacks-of-all-trades. Demand for them is clearly growing and even the United States has acknowledged their value for the Littoral Combat Ship (LCS) programme is a frigate in all but name.

There are requirements for about 100 frigates worldwide while another 60 are currently under construction. These include the Argentinean ARA Gomez Roca, which is the last of six Meko 140 (Espora class) ships the construction of which began 20 years ago. Funding difficulties have delayed progress on this programme and that of Brazil's Barrosso class corvettes which were ordered in 1994 but which will now be restricted to a single hull.

Several programmes are drawing to a close including Spain's Alvaro de Bazan class with the Blas de Lezo and the Mendez Nunez due for completion within the next two years. The programme has proved so successful that another two ships may be ordered later.

They are built around the Lockheed Martin Aegis combat system by Izar, which is also building the first of five similar frigates for Norway as the Fridtjof Nansen class with delivery between 2005 and 2009. The last two of these ships might be built in Norway at yards that already supply modules to Izar. South Africa will receive the last of four Meko A 200 (Valour) class, the SAS Mendi, next year and she, like her sister ships, will then receive a mixture of imported and domestic weapon and electronic systems with the lead ship, the SAS Amatola, being commissioned late next year.

Germany

The German Navy has a $ 2.4 billion requirement for eight F125 frigates and a programme for these ships was scheduled to begin in 2010. But with German yards short of orders, like most of their European competitors, it has been reported in the German press that the programme will be brought forward either to this year or next. However, the role of these ships would suggest that they should actually be labelled destroyers.

Interestingly, Lurssen, best known for fine fast attack craft designs, is proposing a 2800 to 3500-tonne, 100-metre-long frigate design for export. The Advanced Lurssen Combat Craft (ALCC) will be an all-electric ship using gas turbines driving a high temperature superconducting generator and a podded propulsion system with four water jets. It is anticipated that construction will begin in 2006 or 2007.

Meanwhile, the Meko concept pioneered the idea of a general-purpose hull into which specialised weapon/sensor modules could be added. The ultimate application of this must be the American LCS programme, which has recently been cut back from an estimated 60 hulls to between 40 and 50.

Washington is seeking a vessel capable of conducting a wide range of roles including anti-surface warfare (ASuW), antisubmarine warfare and mine countermeasures, but the high speed (up to 50 knots) requirement seems a dubious asset for the last two roles. The plan is to address the mission with a series of sensor, weapon and payload modules which will be installed when needed rather like the Danish Flyvefisken multi-role warships.

The short-list for the first three Flight I demonstrators, which will be built from 2008, consists of two consortia; the first led by General Dynamics and Bath Iron Works, who are offering a 125-metre trimaran design. The second team is led by Lockheed Martin and Raytheon who offer an 80-metre surface effects ship design based on the Norwegian Skjold class fast attack craft.

Denmark

Interestingly, Denmark has modified the Flyvefiskens into dedicated role vessels but it is using some of the modules in its new frigate type ships. The three frigates, officially described as patrol ships, are to replace the Niels Juels class, but will be 137 metres long with a displacement of 5000 tonnes and will carry a Lockheed Martin Mk 41 launch system--initially with Evolved SeaSparrow Missiles (ESSM) but possibly Tomahawk land-attack or SM-2 area defence missiles sometime later. The ships are smaller versions of the 6300 tonne Flexible Support Ships, which are also transports and command ships but which will have a United Defense Mk 45 Mod 4 5-inch (127 mm) gun. This is likely to be installed in the Patrol Ships of which the first will enter service in 2009, two years before the Flexible Support Ships.

The Danish ship designs incorporate much shaping to reduce the radar and infrared signatures.

France-Italy

Sharp signature reduction shaping is also a feature of Europe's largest frigate programme, the 4800 to 5000-tonne Franco-Italian Fremm (Fregates Europeennes Multi-Missions), the first of which are scheduled to begin entering service in 2008, with a delivery spread over ten years. The 27 ships will include a common hull and combined gas turbine/diesel propulsion and will also incorporate a DCN Sylver missile launching system, but there are likely to be considerable differences in sensor and weapon fits. Out of the total of 27 ships planned, (17 for 'France and 10 for Italy representing an overall budget of 9000 million [euro]) twelve have been firmly committed to date.

Each navy plans two versions; ASW and general-purpose/land attack. The French plan to have eight ASW vessels (designated F-ASM) to replace the Tourville and Georges Leygues classes and nine general-purpose ships (designated FMM/F-AVT) to replace the D'Estinenne d'Orves (A69) light frigates. These ships may receive the equivalent of $ 6.1 billion in private finance from French banks. Italy plans to have four ASW and six general purpose ships to replace the Lupo and Maestrale classes.

Shaping is now a common design tactic and is certainly a feature of the six 3200 tonne Formidable (Project Delta) class ships designed in France. The first of class is being built in that country while the remainder will be produced in Singapore. These ships, which will join the Singapore Navy from next year, also feature the DCN Sylver launcher and were the first to be fitted with Thales Herakles radar, which will be the prime sensor in the French Fremm.

Down Under

Australia and New Zealand plan to upgrade the Meko 200 (Anzac class) frigates with improved sensors and the addition of ESSM. Within Asia, Pakistan is about to order four Type 22 frigates, possibly Jiangwei II class ships, from China to replace the Leander class from 2008. Taiwan has plans for the Kuang Hua 7 programme in which eight 2000-tonne ships will replace the Knox class, while it is believed Thailand is in negotiation with BAE Systems for two 2400tonne ships similar to the Malaysian Lekiu class, although the British company has refused to confirm this.

Latin America

In Latin America the only other programme involves Venezuela's four Lupo class frigates. Half have received Israeli command systems and Northrop Grumman 21HS-7 sonar but it is unclear whether or not the remaining ships will also benefit from this programme. Chile scrapped its Fregata programme in favour of acquiring four Dutch Jacob van Heemskerk and Karel Doorman class frigates. The navy is also reported to be interested in acquiring two surplus Duke (Type 23) class ASW frigates from Britain. Peru has shown interest in acquiring another two, or even four, surplus Lupo class frigates from Italy.

Baltic and Black Sea

With some 35 corvettes being built and requirements for about 50 the Baltic and Black Seas are Europe's prime centres for corvette activity. Germany is currently working on the first of five 1662-tonne K130 corvettes. These will be built by a consortium led by Blohm + Voss, which ultimately hopes to build ten ships essentially to replace the FACs.The company's A100 design has been selected by Poland for the Project 621 Gawron II programme with two ships being built at Gdynia for delivery from 2005. The same design must also be regarded as the favourite to meet Bulgaria's requirement for a six-corvette force to replace many of its Russian-designed ships over the next ten years.

Karlskronavarvet is producing five 620-tonne Visby class ships for the Royal Swedish Navy. These vessels are remarkable, because in addition to conducting multiple roles--ASuW, ASW and mine countermeasures--they must be regarded as the stealthiest ships in the world in terms of design and material with almost all weapon systems under the skin, much of which consists of radar absorbent material. Outfitting problems have delayed the programme but the lead ship is scheduled to be commissioned at the beginning of 2005.

The smaller Scorpion class, with nine scheduled to begin replacing the Tarantuls, is also well shaped, although it is unlikely that so sophisticated a design as the Visby is under construction at St Petersburg. The other European requirement is Greece where the Elefsis yard is to produce a VT 100-metre design corvette from 2009, with an option on a second, although the equipment requirements suggest these ships might actually be frigates.

Middle East and Asia

The Middle East is another corvette hot spot because most navies operate in confined waters. Iran has built the 1200 tonne Mowj, possibly based upon the Vosper Mk 5 light frigate but no further details are available. Across the Gulf in the United Arab Emirates work is about to start upon Project Baynunah (formerly Lewa 2) involving the construction of four CMN BR 67 designs by the Abu Dhabi Ship Building company. Four of the 500-tonne ships will be built, with options on two more, with the first delivered in 2008.

Israel has a requirement for three corvettes but this programme was disrupted by the desire of the out-going chief of the naval staff for long-range amphibious warfare ships. This plan has apparently been scrapped and the corvettes are unlikely to appear before the end of this decade. Mention should also be made of a long-standing Kuwaiti requirement for four 88-metre offshore patrol vessels whose equipment requirements suggest they would be corvettes outright. This programme, however, has been much delayed and may be suspended indefinitely.

The same offshore patrol vessel term is being used by Malaysia for the first of six Meko 100 ships (Kedah class), which are initially being delivered with a TRS-3D/16ES air/surface search radar, an Oto Melara 76 mm Super Rapid gun and an Oerlikon Contraves TMEO electro-optical director. However, they will later be able to fit a sonar and surface-to-surface and surface-to-air missiles and are clearly corvettes. Ultimately there are (over ambitious) plans for another 21.

Indonesia is having the two Sigma class ships being built by Royal Schelde for delivery from 2008, Vietnam is building the second of two BPS 500 (Project 12418) ships from Russian-produced kits delivered in Ho Chi Minh City and it appears Myanmar is producing the second of a Chinese-designed 75-metre, 1200-tonne design in the Sinmalak Shipyard with two more to follow, although no details are available.

Corvette requirements exist in India, where four 2000-tonne. 90-metre ships are required primarily for ASW while the Philippines has a requirement for three or four new ships. The latter is slightly confusing for there is reported to be an agreement with Canada's CAE to design and to build the ships in Filipino yards under a $600 million lease-purchase agreement but there are doubts now whether Manila's precarious economic situation will permit progress.

In China four new Type 054 class vessels will begin to replace the Jianghu class from 2005, with India's four 4900-tonne Shivalik (Improved Talwar) or Project 17 ships entering service from 2006. Even the two Russian 1900-tonne Steregushchiy (Project 20380) ships designed to replace the 30-year-old Grisha (Project 1124) class feature considerable shaping and a combat system which, for once, will be close to Western standards. Incidentally, the Granit Research Institute in St. Petersburg, which developed the command and control system for the Steregushchiy class, is also involved in the joint Russian-Indian Brahmos company, which is developing the missile for installation on Indian ships. It is now strongly believed that the Brahmos has been given a land attack capability. For the time being it appears that the only missile planned in future for the 20380 is the Onyx/Yakhont.

Bangladesh does not intend ordering new frigates to replace its three 50-year-old former British frigates but will upgrade its brand new modified Ulsan class frigate, which was decommissioned for an upgrade shortly after delivery The Jianghu class frigate will also be upgraded with a short range AAW system.

Other Projects

In Europe, Belgium plans to replace its three Wielingen class frigates from 2010 with an unspecified number of 4000- to 6000-tonne multi-purpose escort vessels and Turkey had a six-hull Turkish Frigate 2000 (TF-2000) programme which was estimated at two to three billion dollars but has now been postponed due to national economic weaknesses. Portugal had plans to order new hulls to replace the three Joao Belo class but may find it more cost effective to acquire former US Navy Oliver Hazard Perry class frigates. Bulgaria would reportedly like to acquire three frigates but with limited resources would now need to take a closer look at the second-hand market.

The abovementioned ships are also used by Spain (Santa Maria class) and by Australia (Adelaide class). The Spanish plan to upgrade their ships, while Australia is upgrading four of its six ships with radar and sonar sensor improvements and the replacement of the SM-1 area AAW system with SM-2. Spain may follow suit, while the United States is currently removing the AAW missile systems from those ships it intends to replace and is carrying out some sensor upgrades. Romania is receiving two former British Type 22 frigates which have had their Seawolf missile system replaced by an Oto Melara 76 mm Super Rapid gun. Deliveries began this year and in 2008-2009 the ships will receive new command and missile systems. A similar upgrade is underway with Chile's Type 22 frigate.

More design details on the newest generation of corvettes and frigates, particularly from the United States, Russia and Europe, will be published in the Euronaval show report in the next issue of Armada International.