NATO FRIGATES Current Situation And Future Design Trends

Transatlantic reinforcement and resupply would be a critical factor in the conventional defense of Central Europe. Even considering major improvements now planned in airlift and pre-positioning of materiel, the bulk of equipment and resupply would have to come by sea. In addition, the economic survival of European members of the North Atlantic Treaty Organization (NATO) depends on trade and raw materials from overseas; more than 90 percent of the imports of these countries moves by sea.

The Warsaw Pact countries are not dependent on sea transport of imports or exports, and it is impossible to interpret the massive buildup of the Soviet Navy as other than offensive in strategic concept. For this purpose, the U.S.S.R. has amassed a fleet of more than 400 modern submarines, four aircraft carriers and a battle cruiser, with more of these types to follow. The Soviet Navy also has 40 or more cruisers and a large number of destroyers, frigates and smaller ships. The naval air arm numbers more than 1,500 aircraft.

A recent NATO document synthesizes the strategic scenario for North Atlantic naval defense, which could also be applied to the Mediterranean flank of the alliance.

The main wartime task of the growing Soviet fleet is seen as the interdiction of NATO supply lines. For this reason, since the early 1970s, antisubmarine and antiship capability has been improved greatly in NATO navies. In particular, a new generation of multi-purpose surface vessels has been developed, such as frigates and corvettes, capable of fulfilling a complete range of missions in deep and coastal waters. Before the current widespread interest in these types of ships, frigates and corvettes had been conceived as second-rate escort units, with primary ASW mission and secondary anti-aircraft, self-defense capabilities.

The new frigate/corvette designs incorporate advanced performance and up-to-date weapons systems and electronics—a major technical and operations evolution that is making these ships the backbone of modern, well-balanced navies.

In Europe, considerable interest has grown toward making the latest generation of corvettes and frigates the solution to several operating and economic problems.

This type of ship will be discussed in the following review.

In general terms, without taking into account particular operational requirements, a modern frigate could be defined as a warship whose main tasks require the capability to carry out multiple missions in an environment of multiple threats—surface, subsurface and air. These missions could well include: • long-range convoy escort; • engagement of surface naval vessels and interdiction of enemy merchant traffic; • hunter-killer operations against submarines; • shore bombardment and support in large-scale landings or commando operations.

Displacement increased from about 1,500 tons to the range of 2,500-4,500 tons due to the multiple tasks and the seriousness of the threats—mainly submarine and missile. For these reasons, on the technical side the frigate concept has evolved gr eatly since the 1960s.

Among the advances were the introduction of the gas turbine for main propulsion, and advanced weapons systems and electronics including surface-to-surface and surface-to-air missiles, anti-missile systems, electronic warfare systems, command and control, etc. At least one shipboard helicopter is a standard feature in most designs.

Considering these trends, in 1968 NATO established the Project Group II to study the 70s standard frigate as a common basis for the requirements of all navies in the alliance. But when the design was proposed, insurmountable difficulties prevented a common solution.

Different national requirements and pressures from national industries did not permit a single, unique design, and this ambitious program resulted only in a simple list of technical indications about weapons systems, electronics, propulsion plants, etc.

There are now eight different interpretations of the Type 70 frigate on duty cr building for NATO navies, all very different in performance, operating capability and equipment.

Belgium opted for a national design, the E 71, tailored to the country's needs and characterized by fixed operational areas and fixed and rather well-known threats. Displacing 2,300 tons, four Wielingen Class frigates have been built by two Belgian shipyards, Beolwerf and Cockerill-Ougree, and commissioned in 1978. These compact units are armed with four Exocet surface-to-surface missile launchers, an 8-cell Sea Sparrow surface-to-air missile launcher, a Creusot Loire 100-mm gun, a 6- barreled Creusot-Bofors antisub- marine rocket launcher, and two torpedo tubes.

Conceived mainly for escort missions, the E 71 frigates are not equipped with helicopters or an anti-missile weapon system, but after the Falklands war the Belgian Navy began selection of a suitable type to install in the Wielingen Class.

Main electronics are provided by the Dutch firm HSA, and include the fully integrated and automated command and control system HSA SEWACO 4; the sonar is a U.S.-built Westinghouse SQS 505 A.

The Wielingen propulsion plant is based on a Rolls Royce Olympus TM 38 28,000-bhp gas turbine and two Cockerill C0.240 diesel engines in combined diesel or gas (CODOG) arrangement. Maximum speed is 29 knots and range is 4,500 miles at 18 knots.

In 1978 Canada approved a Patrol Frigate Program for six units to be built in national shipyards.

After a long selection process, the contract was awarded recently to a consortium of St. John Shipbuilding and Sperry. Basic requirements are for a ship of 4,000 tons displacement armed with Harpoon surface-to-surface missile launchers, a point air defense missile system in vertical launchers (probably Sea Sparrow), a medium gun (Bofors or OTO Melara), an anti-missile weapon system, two Sea King large helicopters in a hangar, and ASW torpedo tubes.

The propulsion plant will be based on gas turbines (probably GE LM 2500) in CODOG configuration.

Denmark placed an order in 1975 with the Aalborg Waerft yard for three light frigates of 1,300 tons displacement designed by the British Y-ARD firm. Designed for operations in the Baltic theater, the Niels Juel Class ships are all in service and present a well-balanced weapons array, including eight Harpoon surface-to-surface missile launchers, an 8-cell Sea Sparrow surface-to-air missile launcher, a 76-mm OTO Malara compact gun, and four antisubmarine torpedo tubes. A General Dynamics RAM missile/anti-missile system will be fitted to complete the weapons package.

Main propulsion for the Danish ships is provided by a General Electric LM 2500 18,400-bhp gas turbine and two MTU diesel engines in CODOG arrangement; maximum speed is 30 knots. Radars and sonars are from Plessey; fire control systems and combat information center are from Philips (Sweden). No helicopter facilities are provided.

France did not participate in NATO's Project Group II but the French Marine Nationale developed for its own operating needs a type of light escort ship, and in 1972 began a program for 18 units characterized by simplicity, economy and ease of operation. Known as the A 69 or D Estienne d'Orves Class, these 1,300-ton light frigates were designed by Direction Techniques des Constructiones Navales and built by the Lorient Naval Dockyard using prefabricated modules extensively.

Primarily intended for coastal ASW operations, the French ships are fitted with rather light armament— two or four Exocet surfaceto- surface missile launchers, a 100-mm Creusot Loire gun, an antisubmarine rocket launcher, and four torpedo tubes. Electronics are from Thomson CSF and CSEE.

Propulsion is provided by two S.E.M.T.-Pielstick 12,000-bhp diesel engines driving two shafts; maximum speed is 24 knots.

Federal Republic of Germany requirements influenced greatly the decisions of NATO's Project Group II for a new type of frigate.

Bundesmarine required particular characteristics of seaworthiness, endurance, multi-role capabilities, and combat effectiveness. Similar in appearance to the Dutch Kortenaer Class, the F 122 or Bremen Class frigates have been designed by Bremer Vulkan. Six ships were ordered at four yards; the first three are already in service and the remaining three will be completed in 1984.

The Bremen frigates have a displacement of 3,500 tons and are conceived to fulfill a wide range of missions in the North Atlantic theater. Armament includes eight Harpoon surface-to-surface missile launchers, an 8-cell Sea Sparrow surface-to-air missile launcher, two General Dynamics RAM anti-missile systems, two multiple air defense Stinger missile launchers, a 76-mm OTO Melara compact gun, a Breda 105-mm rocket launcher, and four ASW torpedo tubes. Radars and fire control systems are from the Dutch firm HSA, and sonar from Krupp Atlas.

The propulsion system includes two General Electric LM 2500 gas turbine totaling 51,600 bhp and two MTU diesel engines in CODOG arrangement. Maximum speed is 30 knots; range is 4,000 miles at 18 knots. On board are carried two Westland Lynx antisubmarine helicopters with AQS 18 sonar; these are capable of being armed with guided antiship missiles.

The acceptance of these new frigates represents an important step in the modernization of the West German Navy; it is intended that these vessels will form the backbone of the Bundesmarine.

The principal role of the Bundesmarine, within the NATO sphere of operations and together with other allied navies, is to provide escorts, antisubmarine and antiaircraft defense to insure that shipping routes in the North Sea and the Baltic approaches are kept open for allied reinforcements during times of tension or war.

The principal role of the Bremen Class frigates will be to escort to Northern Europe the convoys that have crossed the Atlantic, and to provide all-around defense against air, surface and subsurface attacks.

Secondary roles include the prevention of Warsaw Pact amphibious operations in the North Sea area or the exit of ships from the Baltic to join with other Soviet naval forces in the Atlantic.

Great Britain's participation in NATO's Group studies was limited, preferring an independent program with different technical and operational requirements. Primarily designed for antisubmarine missions and to operate with large task forces or as convoy escort, Britain's Type 22 frigates have good characteristics of seaworthiness and endurance. Named Broadsword, the class includes 13 ships divided into three batches— all built or to be constructed by Yarrow (Shipbuilders) Ltd. in Scotland. Each batch shows marked differences, even in displacement— 4,000, 4,500 and 4,700 tons.

The eight ships of the first two batches are firmed only for missiles— four Exocet surface-to-surface missile launchers, two Sea Wolf surface-to-air six-barreled missile launchers, and six antisubmarine torpedo tubes. When they first appeared these units were considered by many observers to be under-armed, and gave place to discussions of their high costs, sophistication and diversity from the configuration of the other NATO country frigates.

During the Falkland war the Broadsword frigate fought bravely, and her Sea Wolf missiles provided the best, defense against Argentinian air attacks, particularly at close range and low-level conditions.

However, this vessel showed some limitations in the lack of guns to use against enemy fast attack craft or to support amphibious operations. For this reason, the five units of the third batch ordered by the Royal Navy after the South Atlantic conflict will show some additions in the armament, with a 4 5-in. gun forward and two 30-mm twin-mounts; even the Sea Wolf system will be modified to improve its anti-missile capabilities. All the Type 22 frigates are capable of carrying two Sea Lynx helicopters armed for antisubmarine or antiship operations.

The electronics of this class are among the most sophisticated, particularly command, control and information systems, which can coordinate important air-naval operations.

Sensors are from Marconi, Kelvin-Hughes and Plessay.

The propulsion plant is a COGOG (combined gas or gas) installation with two Rolls Royce Olympus gas turbines with a total of 56,000 bhp and two Rolls Royce Tyne gas turbines of 8,500 bhp total providing a maximum speed of 30 knots and a cruising speed of 18 knots with an endurance of 4,500 miles.

Italy, with an important role in the Mediterranean theater, planned her new frigates according to the NATO Project Group concept but with specific technical and operating requirements to meet the increasing presence of the Soviet fleet and other potentially hostile navies. The principal mission of the Italian Navy is, together with the U.S. Navy's Sixth Fleet, to provide defense to the convoys from Gibraltar to friendly ports and to prevent operations by enemy naval forces. A high-intensity threat level characterizes the Mediterranean situation, and the Italian Navy developed an advanced multi-role frigate class with powerful and well-balanced armament but a limited displacement.

Five of the eight 3,000-ton Maestrale Class frigates are already in service. Together with four Lupo Class 2,500-ton frigates, they represent the modern nucleus of the Marina Militare Italiana.

The Maestrale vessels were constructed by the C.N.R. shipyard in Riva Trigoso, with extensive utilization of prefabricated modular elements.

The design employs, as much as possible, propulsion system, equipment, weapons systems and undoubtedly the experience achieved with the 18 Lupo Class frigates that were built, 14 of which were exported to Peru, Venezuela and Iraq. The Maestrale Class has been duly adapted to the specific tasks required, particularly all the precautions suggested by up-to-date technology and rules aimed at reducing noise levels in order to optimize antisubmarine characteristics.

The armament includes four OTOMAT surface-to-surface missile launchers, an 8-cell Aspide (Selinia) surface-to-air missile launcher, a 127-mm OTO Melera gun, two DARDO systems with two twin 40-mm BREDA turrets, two SCLAR 105-mm rocket and flare launchers, and two triple torpedo tubes.

To carry out antisubmarine operations, considered the unit's main task, each Maestrale is equipped with two AB 212 helicopters, and Raytheon variable-depth sonar aft.

Other sensors and electronics include Selenia radars, Elsag fire control system, Elettronica ECM/ ECCM, Elmer telecommunications, etc. A Selenia IPN 10 provides an advanced and integrated command and control systems.

The propulsion plant is a CODOG configuration employing two Fiat/General Electric LM 2500 gas turbines with 50,000 total bhp and two GMT diesel engines with 11,000 total bhp. Controls of main engines and electric power plant are fully automated. Maximum speed is 33 knots; cruising speed is 21 knots with a range of 6,000 miles.

After the preliminary meeting of the NATO Project Group, Netherlands found that its require ments were very similar to those of the German Navy. Thus in June 1973 a Netherlands/German Group was established, and a year later defined their main weapons configuration, which in essence is identical to the NATO frigate concepts.

This binational design provided great advantages through standardization of various ship systems and also allowed training and maintenance to be standardized, with resultant cost savings.

The German version has several differences but the cooperative effort produced a joint procurement program leading to further cost savings.

The Netherlands Kortenaer Class includes 10 standard units, now all in service, and two antiaircraft frigates now under construction at RSV shipyard. With full-load displacement of 3,700 tons, these ships have good characteristics of sea-keeping and endurance, and are designed to provide complete defense against air, surface and undersea threats.

Armament of the standard frigates includes eight Harpoon surface- to-surface missile launchers, an 8-cell Sea Sparrow surface-toair missile launcher, a 76-mm OTO Melara gun, a 40-mm Bofors gun, and two twin antisubmarine torpedo tubes. The 40-mm gun will be replaced with a HSA Goalkeeper 30-mm 4-barrel anti-missile system. For antisubmarine operations, the Kortenaer ships are provided with two Lynx helicopters.

The two antiaircraft frigates have a different armament configuration, without the 76-mm gun and the helicopter pad and hangar but with a Standard MR A/A longrange missile launcher. These ships are also provided with command and control facilities for a task group commander and his staff.

Sensors and other electronic equipment are from HSA, including a SEWACO III Command, control and information system, and a RAMSES ECM system. Propulsion plant is a COGOG configuration with two Rolls Royce Olympus 50,000 total bhp gas turbines and two Rolls Royce Tyne 8,000 total bhp gas turbines.

Maximum speed of the Kortenaer frigates is 30 knots and the range is 4,700 miles cruising at 16 knots. Two ships of this class were bought by the Greek Navy in 1980. Portugal also selected this type, one to be delivered by the RSV yard and the other two to be built under licence but economic conditions have stopped this program.

Turkey, after a long evaluation and selection, recently signed a contract with the German yard Blohm + Voss for four frigates of the MEKO 200 type; two will be built in the Federal Republic and the other two under licence in Turkey, probably at Goluck Navy Yard. This is a completely new design design based on the "containerization" system MEKO for rapid interchangeability of weapons or electronics systems without extensive conversion work.

Technical details are not yet available, but the MEKO frigates will displace 2,400 tons at full load and will have a multi-purpose weapons system with eight Harpoon surface-to-surface missile launchers, an 8-cell Aspide surface- to-air missile launcher, a 127- mm FMC Mk 45 gun, two or three Contraves Seaguard anti-missile systems, and two triple torpedo tubes. A fixed hangar will accommodate an Agusta Bell 212 antisubmarine helicopter.

Propulsion of the MEKO will be all-diesel, with four MTU engines totaling 26,000 bhp on two shafts; maximum speed is 27 knots.

The only NATO naval force without latest generation frigates is the Royal Norwegian Navy, which operates five Oslo Class ships built in the mid-60s at the Naval Dockyard in Horton, and later refitted with Penguin surface- to-surface missile launchers and a Sea Sparrow surface-to-air missile launcher.

The U.S. Navy, with its own particular technical needs and operational requirements, participated only marginally in the NATO Project Group studies. In fact, the U.S. decision was for a "low mix" unit, a ship as inexpensive as possible but capable of operating as an escort on the Atlantic supply route or to be effectively integrated into a large task group.

The capability to operate alone was only partially considered. The main problem was the economic one; in emergency situations or in wartime, large numbers would be needed and as many as possible should be built.

In the early 1970s, the U.S.

Navy planned the construction of a class of 59 frigates—the FFG-7 program. They were follow-on ships to the large numbers of ocean escorts (DE and later FF) built in the 1950s, but with emphasis on anti-missile and antiship defenses.

These would complement other units that emphasized antisub marine capabilities, such as the Knox Class fitted with SQS 26 large sonar and ASROC. The new frigates have a viable antisubmarine role, employing a medium sonar and two helicopters plus the Mk 32 torpedo tubes and weapons system for close-in defense.

The lead ship, named Oliver Hazard Perry, was authorized in the Fiscal Year 1973 new construction program; the last, with the Navy number FFG-60 and as yet unnamed, was authorized in the FY 83 program. To permit series building with its attendant large-scale economies, construction of all 59 ships of the Perry Class was allocated to two companies— Bath Iron Works at Bath, Maine, and Todd Shipyards Corporation's yards at San Pedro, California, and Seattle, Washington.

To date, 38 of these frigates have been commissioned and the program is to be completed in 1987.

The Perry Class ships are slightly longer but lighter than the earlier Knox Class, with a full-load displacement of 3,600 tons.

They have been designed to fulfill basic requirements of seaworthiness, long range and comfortable crew accommodations. Fin stabilizers will be fitted at a later date; space and weight considerations are in the design.

Armament includes a single-arm Mk 13 missile launcher capable of firing both Standard MR surfaceto- air missiles and Harpoon surface- to-surface missiles. A mixed missile magazine provides for 40 Harpoon/Standard Missiles.

The Perry Class features a medium- to long-range defense missile system, whereas the other NATO frigates have the short- to medium-range point defense Sea Sparrow or Aspide 8-cell launcher.

At the same time, the Perry's only launcher has to fire the Harpoon antiship missiles (instead of the six to eight independent launchers on the European frigates) and this fact is considered a severe limitation in the event of damage.

The principal gun on the Perry is a single 76-mm OTO Melara with a firing rate of 90 rounds per minute. One 20-mm Phalanx Mk 16 CIWS (Close In Weapons System) is to be fitted atop the hangar as a last-ditch anti-missile defense.

Two side-by-side hangars can accommodate two Kaman SH2F LAMPS-2 helicopters capable of antisubmarine and antiship operations, or after 1985, the new Sikorksy SH60 LAMPS-3 helicopters.

The Mk 92 fire control system is installed atop the bridge and has a dome-shaped antenna. Other sensors include a Raytheon SPS 49 long-range radar, a Westinghouse SPS 55 search and naviga- tion radar, and a Lockheed STIR (modified SPG 60) illuminator radar for controlling the M13 missile launcher and the 76-mm gun. The European frigates, following the system redundancy principle, generally have a radar for each weapons system.

The propulsion plant is a COGAG installation with two General Electric LM 2500 40,000 total shp driving a single shaft.

The Perry Glass is fitted with two retractable propeller pods aft of the sonar dome to improve berthing maneuvering and to provide take-home power in the event of damage to the main engines or to the the propeller shaft. Each pod has a 325-hp motor to provide W r i t e 8 2 0 on Reader Service Card a speed of 10 knots. Maximum speed is 29 knots and range is 4,500 miles at 20 knots.

Four frigates of the Perry Class were ordered by the Royal Australian Navy. Three of them, known as the Adelaide Class, are now in service; six additional "simplified" ships are planned for construction under licence in Australia at Williamstown to replace the River Class.

Three ships of the Perry Class are building under licence in Spain by Bazan de Construcciones Navales Militares at Ferrol for completion in 1985-87; two more have been approved for probable completion in 1988. The Spanish version will be faster and will include some modifications to the weapons systems, with the Harpoon surface- to surface missile launchers mounted on the upper deck and a 20-mm multi-barrel Meroka system in place of the Phalanx CIWS.

To sum up, this wide range of design differences has been the disappointing outcome of the NATO Project Group II study that envisioned a common type of frigate for the 1970s. Of the 14 navies analyzed, there were 11 different ship types with wide variations in the weapons systems, electronics, propulsion plants, etc. On the other side there are the Warsaw Pact fleets where ships, armament, electronics and propulsion plants are all of Russian origin with a very high level of standardization.

In late 1980 a new NATO Group was established to study "Frigate Replacement 90." This program is aimed at having new ships entering service towards the mid-1990s.

These vessels are not intended to replace the present generation frigates described above, which at that time will be between 10 and 15 years old, but rather to fill other replacement needs such as the German Homburg and Lutjens Classes, the Dutch Von Speijjk Class, the British Leander Class, the U.S. Knox Class, and others.

Seven countries—Canada, France, Germany, Italy, Netherlands, United Kingdom and United States—have agreed to participate in the project, which envisions a NATO antisubmarine frigate with a conventional hull. Of course, it remains to be seen if different national requirements will allow for a common design, or at least a common list of guidelines.

Such an ambitious project has met with skepticism in most NATO countries. However, in December 1982 the first prefeasibility study demonstrated clearly that tremendous savings could be achieved if nations build the same type of warship—something on the order of $5.6 billion for 100 frigates over a 10-year period, about 21 percent of the total cost. Moreover, there should be further savings during the expected 25-year life span of these ships of some 12 percent in the cost of operating and maintaining them.

In making this study the designers were free to select equipment meeting the stated capability requirements from the full range of systems available in NATO countries, including items that are not yet in production. The study was conducted with parametric analyses to demonstrate the relative effectiveness and impact on ship size, configuration and cost for each of the system concepts and alternative ship designs.

The study also evaluated what industrial organization would be needed to move the project through the subsequent phases of feasibility study, project definition and production. Representatives from the interested countries participated enthusiastically in the study; more than 90 companies provided some 150 technicians who met frequently.

After completion of the prefeasibility study, each government made a national evaluation of the results before joining with their allies in the Project Group to arrive at a NATO decision. At a meeting in April 1983, all seven participating countries, plus Belgium and Spain, gave the green light for a continuation of the project, towards the final target to produce a lead ship in 1992.

But what will be the shape of the frigate of the future? Despite the many theoretical advantages, it is very unlikely that unconventional hull designs such as catamarans, hydrofoils or surface effect ships (SES) will be seriously considered for frigate type vessels before the end of the century. In that case, the most promising concept appears to be the SES.

Frigates of the next two generations will consequently be of the displacement type. This does not mean that their architecture will not evolve; two main trends are toward reducing the ship's radar and IR signature and toward an increasing use of modular construction elements. When combined, these factors are likely to result in vessels with smaller, lower and more simplified superstructures than the frigates now in service.

Other important changes could result from innovations in electronic and armament technology.

Development of conformal radars with flat antennae would allow designers to dispense with the presently necessary forests of masts and to realize far simpler and lower superstructures. Also, the next generation frigates will have vertical launch systems for the surface-to-air missiles of short to medium range such as the Sea Sparrow, Aspinde, Sea Wolf, etc.

These same concepts could be applied to the future antiship missiles, with many advantages for the systems' reliability. The main gun will maintain its role, and introduction of guided ammunition will improve its capabilities.

Greater emphasis will be placed on anti-missile defense with development of conventional or missile systems to face the threat of the second generation supersonic seaskimmer antiship missiles. Growing in importance will be the helicopters— in the future completely indispensable for the ship's defense— not only for antisubmarine hunter-killer operations but for antiship missions, particularly against fast attack craft.

In the propulsion sector, developments are foreseeable in gas turbines; all the possibilities of the CODOG, COGOG and COGAG combinations are still to be explored.

However, the foremost requirement for the future frigate is the reduction of underwater noise for better ASW operations.

Other changes will involve automation systems to reduce manning and insure a constant control of main engines, power generation plants, electrical equipment, etc.

Some navies are testing optical fibers for data distribution; such connections between information services or command centers and users everywhere in the ship would provide better performance than traditional cable networks, and savings in volume and weight.

In the electronics sector, a wider employment of laser and optical technologies is foreseeable. Other improvements will impact command, control, communications and information systems, which will represent the "brain" of the future frigates.

The lessons learned in the Falkland/ Malvinas war have prompted all navies to give added consideration to the factors that affect the survivability of ships in combat situations. These include damage control systems; redundance and independence of anti-fire stations and emergency power supplies; fireproof cables and internal communication networks; and the materials used for construction and outfit of the ships.