The main challenge is to strike a correct balance between size and weapon systems:
-ships that would need to be smaller – for coastal waters – are the most vulnerable.
-fast attack craft are not a panacea, whilst
-over-arming frigates would turn them into destroyers.

The new concept of containerised equipment would allow additional weapons to be installed as funds permit.

Stealthiness is still antinomous with navy.

In terms of co-operation, nations have a lot to learn from industry.

 

By Antony Preston

Nato's definition of a frigate is a single-rôle ship, or least one in which one rôle predominates. But a large frigate has a variety of weapons, including an air defence system, long-range anti-ship missiles and one or two helicopters capable of attacking both underwater and surface targets, and each of these is very effective in its own sphere.

The US Navy has cut back its force of frigates, having disposed of all its numerous Knox (F-1052) class, and is making inroads into its surviving Oliver Hazard Perry (FFG-7) class. This policy has, of course, the benefit of making a large number of sound, well-maintained ships available for smaller navies, but it robs the US Navy of useful second-line warships. Other navies are very happy to have second-hand O. H. Perrys, and those who had built their own under licence (Australia, Spain and Taiwan) are looking at ways to extend their service lives.

For a modern frigate, an armament of anti-ship missiles is virtually mandatory, and in this field the Boeing RGM-84 Harpoon has achieved wide popularity, usually in two quadruple groups of canisters. Aerospatiale no longer makes the original MM-38 variant of Exocet, but the MM-40 Block 2 is establishing its own market-share. Although the Italian Navy retains the Otomat (contraction of Oto and Matra) the lack of Italian success in exporting major warships in recent years has affected sales, and although stealth features are being marketed for the Mk 3 variant it will have to fight for scarce funding. The same applies to the Swedish Saab RBS 15, which has sold to a small number of customers; it is claimed to have unique capabilities against targets seeking cover among small islands.

The Polish Navy’s Project 620 corvette Kaszub has a relatively light armament of guns, torpedo-tubes and a pair of Strela SA-N-7 missile-launchers. The design was not wholly satisfactory, and only one ship was built.

For blue-water navies small size is not an option. Size is driven by the need to incorporate a balance of offensive and defensive systems, as well as the sensors and below-decks electronics needed to fight the ship, and fuel for long-range operations. Size is not dictated by the need to provide palatial accommodation, despite many statements to that effect by ill-informed critics.

The biggest problem facing the designers of modern frigates is how to get the balance of weapons and sensors right. Since the Gulf War the emphasis has switched from blue-water escort functions, for which long-range detection of deep-running submarines and effective defence against anti-ship missiles are essential, to littoral warfare, i.e. expeditionary warfare with the intention of landing on hostile shores. Coastal waters have always been high-threat areas for ships; they are within range of shored-based aircraft and coastal defence guns and missiles, as well as mines. They are also targets for small submarines, which know their own local waters better than the invaders. Warships cannot use sea room to disperse because their main task is to protect vulnerable amphibious ships. Today there is also the growing threat from relatively short-range ballistic missiles, accurate enough to launch a biochemical gas or germ attack against a crowded mass of shipping. These threats can and are being countered, but the risk is that warships will become over-specialised and lose their greatest asset, flexibility. Wars have an unfortunate habit of not conforming to the cosy assumptions of peacetime strategists.

Sharing Costs

Even relatively small warships are expensive, and a modern frigate is no exception. This has led navies to follow the route of collaboration, and one very successful example is the collaboration between the Royal Netherlands Navy and the German Navy on their respective air defence frigate programmes. The decision was taken to maximise commonality in areas of major capital cost, notably the main surveillance radar, the combat system and the major weapons. Thus the German Navy's three Sachsen class Type 124 and the four Dutch de Zeven Provincien class air defence frigates have Signaal's Apar active phased array weapon control radar and Smart-L surveillance radar, a Dutch Sewaco FD combat system, American RGM-84F Harpoon anti-ship missiles and Standard SM-2 and Evolved Sea Sparrow Missile (Essm) air defence missiles. On the other hand, each navy has retained control over its own hull-design, and comparatively minor items such as guns, electronic warfare systems, and engines. The Sachsen class are driven by LM 2500 gas turbines and MTU diesels, whereas the de Zeven Provincien class are driven by SM1C Spey gas turbines and Stork-Wärtsilä diesels. Much sterile quarrelling over work-sharing was avoided, reducing the design time and keeping cost under control.

Compare this with the doomed attempt by the British, French and Italians to design a Common New Generation Frigate (CNGF), the Horizon project. It became mired in bureaucracy, with every decision requiring the approval of all the partners, and even the numbers to be built were changed. The Royal Navy needed 12 and stuck to that figure, whereas the French wanted only four and then cut that to two, while the Italians started at two, raised it to six and then finally reduced the requirement to two ships again. In the words of the British Chief of Defence Procurement, 'it was not common and it was not a frigate', for it grew into a multi-rôle destroyer, despite Italian efforts to keep it down to about 2500 tonnes. Like the equally unsuccessful NFR-90 Nato frigate project, the designers left the two most important elements to the end: the combat management system and the anti-air warfare (AAW) missile system. In addition to arguments about work shares, there were differences of opinion about the phased array radar, with the French trying to insist on the Thomson-CSF Arabel and the British refusing to abandon the Siemens-Plessey (now British Aerospace) Sampson system.

The French frigate Surcouf relies on low-observability for protection, and has a relatively weak armament and outfit of sensors. For example, she has no hull-mounted sonar.

When the British pulled out of Horizon on 2 May 1999, they moved quickly to start a national programme, the Type 45, a design displacing some 6500 tonnes. It will be armed with the Principal Anti Air warfare Missile System (Paams) intended for Horizon, but using the Sampson and a British combat management system, and driven by WR-21 intercooled regenerative cycle gas turbines. The Paams is based on the Franco-Italian Aster-30 long-range missile, so the British can claim that they are still co-operating with their European allies. The French and Italians will build a Eurofrigate which is in fact based on the F 3000S frigates building for Saudi Arabia at DCN Lorient. Because the displacement is almost half that of the original Horizon design, its main armament will be the Aster-15, a shorter-ranged version of the Aster-30, the core of PAAMS.

Compare the progress of the Norwegian Naval Materiel Command's acquisition process for the 4700-tonne frigates intended to replace the elderly Oslo class. Several consortia were invited to submit proposals, within a broad specification of weaponry and capability. Out of these, two finalists were selected, Bazán of Spain, teamed with Lockheed Martin as systems integrator, and Blohm+Voss of Germany. In May 1999, Bazán was selected as the favoured supplier, depending on the outcome of negotiations with the Naval Materiel Command. Although main items of weaponry are mandatory: the Kongsberg NSM anti-ship missile and Essm for air defence, the bidders have been allowed considerable latitude in meeting the requirement, and the choice of combat system has still not been decided. Within the build-to-price framework Blohm+Voss offered five hulls, one to be built in Germany and the rest to be built in a Norwegian shipyard, whereas Bazán is offering six, but with hull-sections built at Ferrol and merely assembled in a Norwegian yard. By comparison, the unsuccessful Norwegian Nor-Eskort consortium could only offer four hulls. This discrepancy is accounted for by lower labour-costs in Spain. If the detailed negotiations are not satisfactory the Naval Materiel Command will invite Blohm+Voss to make a revised offer, but the project has since been deferred until the end of the year.

The Royal Netherlands Navy’s M class frigate Willem van der Zaan combines a powerful armament and suite of sensors in a relatively small hull, with a small radar cross-section.

There are limits to how much fighting power can be put into a frigate of modest dimensions. When the Royal Australian Navy launched its Anzac

class project, to build eight modified Meko 200 type ships for its own use and two more for the Royal New Zealand Navy, it was recognised that the Australian Anzacs would be comparatively under-armed on completion, but the Blohm+Voss containerised equipment concept would allow additional weapons to be installed as and when funds permitted.

Since completion, Harpoon missiles have been added, as well as an additional vertical-launch silo for Sea Sparrow/Essm air defence missiles, but ambitions to mount a much more powerful air defence armament are proving much harder to fulfil.

The hope was to retrofit a Standard SM-2 area air defence missile system, with a long-range surveillance radar such as the Apar. But margins for additions may be as low as 50 tonnes, ruling out major additions, and the containerised concept makes internal alterations much harder than anticipated. Last, and perhaps most important of all, the installation of a powerful radar, extra trackers and associated improvements to the combat system will impose massive demands on the auxiliary power supply. One solution proposed is to cut the ship in half to insert an additional section carrying uprated generators, but this would be prohibitively expensive. In fact, the addition of Standard SM-2 would lift the ship out of the frigate category into the air defence destroyer class, a massive change of rôle for a ship originally envisaged as a conventional patrol frigate. British Aerospace has produced schemes for retrofitting its Sampson multi-function radar to the Anzacs, but finding room for its compact antenna and processing equipment is only a small part of the problem.

The Royal Navy of Oman corvette Al Mua’zzar has a powerful armament for her size: eight MM-40 Exocets, an eight-cell Crotale-NG air defence missile-launcher and a 76 mm Super Rapid gun.

The Indian Navy has taken the bold step of ordering three Project 1135.6 Improved Krivak III type frigates from the Russian Baltiisky Zavod shipyard in St Petersburg, and after some months of negotiations over funding, the keel of the first was laid in March 1999. These 3100-tonne ships are based on the Krivak IIIs assigned to the former KGB Border Guard, but with low-observability features incorporated. The first two are to be delivered in 2002, and the third a year later. The Russians have made several efforts to get into the warship export business, but their yards have been dogged by chronic financial problems, including accusations of corruption, so this export success is doubly welcome.

Biting off More…

A significant trend is the evolution of the fast attack craft into the corvette. Ever since the Gulf War, when helicopter-launched light anti-ship missiles destroyed the Iraqi Navy, fast attack craft designers have been trying to improve the defence against anti-ship missiles. But the classic 45-metre type craft, exemplified by the Combattante II, lacks the margin of stability, seakeeping and deck-space to accommodate the bulky systems needed. The Italian shipbuilders Cantieri Naval Riuniti (now part of Fincantieri) led the way with the 550-tonne 57-metre Assad class built for Libya; although configured like fast attack craft, they had a powerful defensive armament of twin 35mm guns. An improved variant was built for Ecuador and Iraq, equipped with helicopter flight decks and lightweight launchers for Aspide air defence missiles, but the Iraqi craft were embargoed in 1990 after the invasion of Kuwait, and four have been bought from Fincantieri by the Royal Malysian Navy. The German Lürssen yard followed suit with a 62-metre design sold to Bahrain and the Republic of Singapore Navy, the Bahrain craft being equipped with helicopter landing decks.

The Republic of Singapore Navy’s missile-armed corvette Valiant is one of six Harpoon-armed Victory class. They are being armed with Barak 2 air defence missiles.

Although these oversized fast attack craft are now universally classed as corvettes, the true corvette is analogous to the frigate, but smaller and generally lacking the high endurance needed by blue-water frigates. Because they are largely intended to work in coastal waters, a strong air defence is needed.

In the mid-1980s the Royal Thai Navy took delivery of two corvettes from Tacoma Boatbuilding in Seattle. The Ratanakosin and Sukhothai carry a very powerful armament on a displacement of only 900 tonnes: Harpoon anti-ship missiles, Aspide air defence missiles and an Otobreda 76mm Compact gun, as well as Stingray anti-submarine torpedoes. Speed is a modest 26 knots and range at economical speed (16 knots) is only 3000 nautical miles, but they are ideally suited for patrolling the shallow waters of the Gulf of Siam. The combination of the STN Atlas DSQS-21C hull-mounted sonar and the Stingray torpedo gives an excellent shallow-water capability.

A very different set of requirements led the Sultan of Oman's Navy to order its first corvettes in 1992, as the Muheet programme. This small Gulf navy has pursued a cautious policy of not procuring ships until the infrastructure and trained personnel are in place. First came a quartet of powerful 56-metre fast attack craft ordered from Vosper Thornycroft, then came an order from the same company for two 83-metre corvettes, intended to patrol further offshore than the fast attack craft, and in all weathers (Oman's coastline is exposed to winter gales). The Qahir al Amwaj and Al Mua'zzar displace nearly 1200 tonnes and have a powerful armament of eight MM-40 Exocet missiles and a Crotale-NG air defence missile system, as well as an Otobreda 76 mm Super Rapid dual-purpose gun. A helicopter flight deck is provided, but no hangar.

The South African Navy was tricked into buying 56-metre fast attack craft based on the Israeli Reshef design, when it really wanted corvettes. Unfortunately the Naval Staff could not agree on details of size and armament, so when two Israeli Reshefs made a much-publicised voyage from the Mediterranean to the Red Sea via the Cape of Good Hope, the then Prime Minister Botha intervened and ordered the Navy to buy a dozen craft from the former Haifa Shipyard (now part of Israeli Aircraft Industries). The Navy was able to cut the order back to nine but has had a long time to regret the hasty decision. The Minister class (now known as the Warrior class) are totally unsuited to the long, steep seas encountered off the Cape, and the author has seen them 'taking it green' over the bow even when running close inshore in relatively calm weather.

The adaptable German Corvette Consortium Meko concept appears to be quite popular.

To replace the Warriors a competition was held, for four corvettes to be delivered as green hulls, i.e. without weapons or electronics, because the South Africans intended to transfer the guns, missiles and combat systems from four Warrior class to reduce the outlay of hard currency. This competition was won by Bazán, but was so bitterly contested by the French (even after the winner had been selected) that the Pretoria government decided to hold a fresh competition. This time the German Corvette Consortium made up of B+V, Thyssen and Bremer Vulkan won, offering the Blohm+Voss Meko A200 design as part of a package involving South African and German suppliers. They will have helicopter decks for operating the GKN-Westland Super Lynx. However, there is many a slip 'twixt cup and lip', and the cash-strapped South African administration is finding it difficult to fund the programme, and orders may be delayed.

Stealth or not Stealth

The question of 'stealth' or low-observability must be addressed. Much is claimed for it, but it is expensive, and customers must ask themselves if the extra cost is justified. For the genuine hardliners, real stealthiness can only be achieved if the technique is applied to the entire ship – and this includes the doors of the gun turret, retractable aerials and so forth – otherwise "it is a waste of time and money". The best, and only, example of a production item is the Karlskronavarvet Visby corvette for which, by the way, the Swedish armed forces supreme commander has cleared funds for another two, bringing the total to six. The Visby also features an ultramodern 9LV combat systems from CelsiusTech.

This is how the Swedes understand stealthiness with their Visby: total.

For the future we can expect to see a requirement for land-attack systems such as Dasa's Polypheme missile, as well as enhanced defence against missiles, both 'hard kill' weapons and soft kill electronic warfare systems. The helicopter has made itself indispensable for frigates, in both the anti-surface and anti-submarine rôles, but an increased emphasis on drones is very likely.

The main difficulty will be trying to contain size. Current powerful corvettes are approaching 1200 tonnes, and frigates have already passed the 3000-tonne mark. It is likely that corvettes will rise to 1500 tonnes in normal conditions and even more when fully loaded with fuel, ordnance and stores. Similarly, frigates will approach the 4000-tonne limit, and much more if they are destroyers pretending to be frigates. The addition of more comprehensive defence systems and offensive land-attack systems make such rises in displacement inevitable, and so perhaps 'stealth' measures will become mandatory to compensate for the increase in size.

Although Third World navies currently prefer diesel propulsion, the gas turbine is likely to become more popular outside the front-line navies as the technology becomes more user-friendly. Another option is all-electric drive, using standard power-units to generate current for electric motors.

They are Needed

What is certain is that navies will continue to need frigates and corvettes to exercise command of the sea, in ways that submarines and fast attack craft cannot. The prophecies made 25 years ago, predicting the end of large surface combatants and the supremacy of the fast attack craft, have not only been proved invalid, but totally wrong. Surface warships have even more importance today than ever before, and the competition between anti-ship weapons and defensive systems is no longer one-sided. Anti-ship missiles exemplify the false doctrine of the 'dominant weapon', to which there is no antidote. It posed such a threat that a lot of money has been spent on finding an answer.