Improving the sting of the corvette. (Upgrade Approach).

Corvettes and frigates are essentially the same type of warship but, even though different navies adopt dissimilar definitions of the two types, are generally referred to as escorts. Although small, they often represent the largest warships in some navies' main force. Moreover, vessels built as recently as a decade ago may be now in need of upgrade, to which must be added the plethora of escorts sold on or 'cascaded down' from larger navies to smaller ones.

Among the elements involved in such upgrades are the obvious elements of on-board equipment: sensors, including radar, sonar and electronic support measures, command and control (displays and processing), satellite, secure and data link communication equipment, inertial and global positioning systems (GPS) navigation and weapons (guns, missiles and torpedoes). In addition, some escorts are equipped with a helicopter, which itself may require replacing or updating.

To explore all these areas is a main feature in itself, so in this instant, two examples must serve as typical illustrations of what can be done.

Greece has, over the last ten years, acquired a dozen Dutch-built Kortenaer-class frigates--two purchased new in the 1980s and ten purchased from the Royal Netherlands Navy after their withdrawal from service, but which were built between 1978 and 1983. In Greek service they are known as S-class frigates. As an aside, it is worth recording that the United Arab Emirates purchased two ex-Dutch Kortenaers in 1996, which have been fitted with air conditioning, the 30 mm Goalkeeper close-in weapons system and Harpoon anti-ship missiles.

With a tight defence budget and funding priority given to the Type 214 submarine programme, frigate replacement is not an imminent priority. So, on 25 November 2002, it was confirmed that Hellenic Shipyards, with Thales Netherlands as prime subcontractor, would upgrade six of these vessels, extending their service life by another 20 years at a cost of some $ 381 million.

These vessels are critical to the future Greek surface fleet. The upgrade, to be undertaken over five years, involves the replacement of the command system (by Tacticos), some sensors, including the Mirador electro-optic sensor, LW08 radar and WM25/Stir fire-control system, and the navigation, engine control and fire fighting systems. The only weapon upgrade currently planned is the migration from the Rim-7 Nato SeaSparrow air-defence missile to the RIM-162 Evolved SeaSparrow Missile (ESSM).

In the case of Greece, this approach was dictated by the present user. In the case of the two ex-Royal Navy Type 22 Batch 2 frigates being sold to Romania, a two-phase upgrade is planned as part of the purchase deal. The government-to-government deal, finally signed on 14 January 2003, calls for the reactivation and first-phase modernisation of two ex-Royal Navy Type 22 Batch 2 frigates--HMS Coventry and HMS London.

BAE Systems Customer Solutions & Support is prime contractor designate for the $187 million package, with Fleet Support Limited (FSL) at Portsmouth, a joint venture between BAE Systems and VT Group, subcontracted for the reactivation and upgrade.

With Romania due to join Nato next year, the acquisition of these warships will give the country's obsolescing navy a significant leap in capability. Once in service, the two 4200-tonne frigates will offer interoperability with Nato forces in the Black Sea.

The pre-transfer upgrade--worth over $ 32 million to FSL--will address the overhaul of the platform and reactivation of various legacy equipment, installation of reconditioned Rolls-Royce Tyne and Olympus marine gas turbines and a limited first-phase combat system modernisation.

Work on the Coventry will begin in August this year, with delivery to Romania by the end of 2004. Work on the London will start in March 2004, with delivery in May 2005. Several major systems will be removed from the two ships during the reactivation, including the Seawolf air defence system, two trainable six-barrel launchers, two Type 911 radar trackers and associated computers, and the MBDA Exocet surface-to-surface guided missiles.

As part of the modernisation, AMS (formerly Alenia Marconi Systems) will upgrade the Cacs command system fitted aboard the two ships, supplying a new Nautis 3 fire control system comprising a ballistics predictor and operator console and interfacing to a Radamec 2500 electro-optical director.

Another addition will be an OtoMelara 76/62 Super Rapid dual-purpose 76 mm medium-calibre gun, which will be installed on the forecastle (the Type 22 Batch 2 ships were originally built as 'all-missile' ships) while Terma will supply its Soft Kill Weapon System, including DLT-12 launchers with an integrated chaff/ infrared decoy system.

The second-phase of the upgrade, planned to take place in Romania around 2008 or 2009, will focus on improving the ships' capabilities with enhanced command, control and communications facilities (to allow their use as flagships), the addition of new air-defence and anti-ship weapons and improved electronic warfare systems.

South America has two interesting frigate upgrade programmes--Brazil with its British-built Niteroi class and Venezuela with its Italian-built Lupo class.

The Brazilian programme, which began in 1995, will see new equipment in the form of sensors--Alenia's Ran 3L and RTN 30X plus a Decca TM 1226, plus a complement of Aspide air-defence missiles to replace the obsolete Seacat, new Shield countermeasures and a Racal (now Thales Communications) Cutlass ESM suite being refit. Plans to replace the diesel engines have been shelved for now, although a new hull sonar is being considered.

In Venezuela, two of the six modified Lupo class frigates have been upgraded by Northrop Grumman's Litton Ingalls Shipyard. The work covered upgrading the Fiat/ GE LM 2500 gas turbines, replacement of the original GMT A230.20M diesels by MTU 20V 1163 diesels, thereby improving the combat data system and sonar plus a new ESM suite from Israel.

It is also worth recording that the United States has disposed of a number of Oliver Hazard Perry (FFG-8) class ships to a number of countries including Bahrain, Egypt, Poland and Turkey (one, two, two and six vessels respectively), all of which may be upgraded to a greater or lesser degree. Australia took six new-build vessels and will be upgrading them to take the new RIM-162 Evolved SeaSparrow Missile, while Spain licence-built six ships and Taiwan received eight.

The US Navy retains about 30 Oliver Hazard Perry class in service, many of which have received updates through various programmes, including a much improved combat data and fire control system, a revised flight deck to support the Rast helicopter landing system and a progressive upgrade of the Phalanx close-in weapon system to the Phalanx IB configuration.