Project F25T Naresuan Class - Archived 11/1997

Outlook

Orientation

Sponsor

China National Machinery Import and Export Corp (Machimpex)

Erligou

Xijiao

Beijing, China

Contractors

Zhonghua Shipbuilding

Shanghai

China

Platform

Technical Data

Characteristics

The hull form is relatively conventional, being flush- decked with marked bow sheer and flare. The rake of the prow is dictated by the installation of a Chinese SJD-7 sonar in a bow dome. The bow form itself has a pronounced knuckle and a large breakwater forward of the main gun. The quarterdeck is covered by the helicopter flight deck, providing a sheltered working area on the fantail. This would normally be used for handing a towed array or VDS fish, but there are no plans for such an installation at this time.

The superstructure is a single unit with the 01 level plated in and a capacious bridge structure. The CIC is located behind the main bridge, but no command system for these ships has yet been specified. Gas turbine intakes are grouped in a central island, the top of which supports the primary search radar. The helicopter hangar is installed aft, with the two 37 mm DARDO CIWS mounted flanking it and the DARDO fire control radar installed on top.

The propulsion system of these ships is a conventional CODOG layout, with two MTU diesels providing cruise power while the LM-2500 gas turbines are used for boost. The propulsion machinery is geared to two shafts equipped with cycloidal pitch screws. There are two machinery rooms, one for the diesels (aft) and one for the gas turbines (forward). The gearing is not installed in a separate compartment, although a soundproofed engineering control room is provided, located between the engine rooms.

Initial Thai reports are that the construction standards of these ships are substantially better than those of the four Jianghu class frigates purchased earlier, but still below those normally accepted for Western construction. A particular problem with these ships is reported to be that design changes imposed by the German technical advisory teams were executed by the Chinese shipyards without altering the other blueprints affected by the change. As a result, the internal arrangement of the ships is illogical, with some compartments having hatchways set in blank bulkheads while other compartments have no access at all.

Air defense is provided by an integrated point defense system which combines vertical-launch Sea Sparrow missiles in an eight-round VLS forward and two Breda-Bofors Twin Fast Forty (chambered for Chinese 37 mm ammunition) mounts aft. The capacity of the forward VLS is restricted by the hull form at that point, there being insufficient hull depth to accommodate a larger VLS. The target acquisition for the gun-missile system is provided by an E/F-band RAN- 10S radar mounted on the foremast. This set was produced under license in China as the Type 360. Two STIR 2.4 radars provide missile fire control (thus giving two missile channels), while the 37 mm guns aft are controlled by an I/J-band RTN-30X Orion radar (license produced in China as the Type 374). The complete structure is effectively a modified and Chinese-produced version of the DARDO CIWS system installed on Italian warships.

Anti-submarine capability is limited. The primary ASW sensor is a Chinese SJD-7 medium-frequency sonar installed in a bow dome. The antecedents of this set are unclear, but there is evidence to suggest it may be the French DUBA-25 system produced under license. ASW weaponry is restricted to two triple Mark 32 torpedo tubes installed amidships. No reload torpedoes are carried. The helicopter aft is tasked with general surveillance duties, target location for the Harpoon missiles and anti-shipping attack with light air-to-surface missiles. Contrary to many reports, no order for these helicopters has yet been placed, although negotiations for ex-US Navy Kaman SH-2F Seasprites are continuing. A reported purchase of nine Chinese Zhi-9 (license-built Dauphin) helicopters never took place.

The electronic warfare fit is a standard Elettronica-designed Newton Beta produced under license in China as the Mirage EW system. This includes an ELT-211 ESM system with a masthead omni and scanner arrays and a DF array wrapped around the foremast under the yardarms. Four jammers are provided, two ELT-318 barrage jammers in cylinders and two ELT-521 deception jammers. All are mounted on the 03 bridge level. The ELT-521 jammers are not mounted in the normal mushroom radomes housing ELT-828 antennas but in a new quadruple-cylinder installation similar to that used for Nettuno. In all cases, the Chinese-built equipment has the same Type number as the Elettronica designation with Type- replacing ELT-.

Variants/Upgrades

The Chinese navy has proposed a variant of this design with an all-diesel propulsion plant. This variant is reported to be under construction for the Chinese navy and also available for export.

Program Review

A compromise was reached by which these four ships would be supplied fully armed and equipped, but utilizing Western systems produced under license in China where possible. Two of the ships were to be modified with helicopter hangars and flightdecks aft. In addition, Thailand would order two more ships of an enlarged design which would be designed to carry Western weapons and sensors from the outset. This design would then be offered by China on the export market, with target customers being in the Middle East and Southeast Asia.

The order for the two ships was signed in October 1989. By mid-1990, Thailand was growing perturbed about the construction standards of the first four ships. Thai naval officers visiting the frigates under construction related stories about watertight doors not closing, a complete absence of internal damage limitation, poor welding standards, exceptionally poor safety standards with regard to electrical wiring and many other faults. Frigates in service with the Chinese navy had poor serviceability and required extensive maintenance commitments. As a result, Thailand decided to cancel its order in September 1990.

This decision was reversed after a compromise was arranged. The design of the F25T class would be revised to incorporate technical advice and assistance from the German shipbuilding industry. The construction of the F25T class would be subject to German technical supervision and would have to pass German quality control inspections at various points in the building process. This was expected to delay delivery of the ships by approximately nine months, with the first ship expected to be handed over in late 1992.

In fact, the building process was to be delayed by substantially longer than this, and the first of the two ships was not ready to run trials until August 1993, some 14 months later than the planned date. At this point the ship was structurally complete but lacked much of its internal electronics. In common with the earlier four ships, the two F25T class frigates required substantial remedial work on their arrival in Thai waters, which delayed their service entry still further.

While the Thai program was in progress, China continued with development of the F25T design and made strong efforts to export the design. The type was one of those offered to the United Arab Emirates to fulfill its eight-ship frigate requirement and was also offered to Turkey. In neither case did the design get past the first selection process. Export promotion of the design continues, with an all-diesel version being offered alongside the existing CODOG ship.

In mid-1995, a delegation from the Pakistan navy visited Thailand to obtain first-hand operational experience concerning the Naresuan class from the Thai navy. This visit coincided with the departure of a negotiating team from Pakistan to China to finalize a major procurement package. The deal is reported to include three "frigates" of unspecified type, two fleet oilers of the Fuqing class and between eight and twelve missile-armed fast attack craft. While the US embargo on military sales to Pakistan continues, the supply of LM-2500 gas turbines for the new ships is improbable. The Pakistan deal therefore probably envisages acquisition of the all-diesel version.

Funding

The F25T design was funded jointly by the Royal Thai Navy and the Chinese State Shipbuilding Corporation.

Recent Contracts

No contractual information is currently available.

Timetable

Worldwide Distribution

Forecast Rationale

The F25T is the latest and most modern small frigate design produced by the Chinese navy. As such, it forms a small, low-cost supplement to the Luhu class frigates. Current reports from China suggest that the F25T design will be produced for the Chinese navy in two versions, one being identical to the Thai F25T, the other lengthened and equipped with a six-barreled launcher for CY-1 anti-submarine missiles as fitted to the existing Jiangwei class. It is also reported that the Chinese navy version will have four diesel engines rather than two diesels and two gas turbines.

The F25T is, however, mostly aimed at the export market, with the Middle East, Africa and Southeast Asia as primary targets. In these regions it has the undoubted advantage that it costs approximately a quarter of the price of an equivalent Western ship. This may be the decisive factor to countries with maritime interests to safeguard yet also with very severe limits on their procurement budgets. Against this low procurement cost must be set the evidence that poor construction standards and difficulties in maintenance make Chinese-built ships expensive to run. This cost balance between procurement and support budgets is a very difficult one to strike.

There are four likely candidates for the Pakistani frigate purchase. The first is the Project 053HT Jianghu IV class as sold to Thailand in 1989. This has the advantages of being the lowest cost option while still offering significant anti-ship firepower. The Jianghu is, however, an old design. It is short-ranged, poorly equipped and deficient in air defense and anti-submarine capability.

These factors would be eliminated by the acquisition of the Project 051 Luda design (see report). The design offers much greater capability than the Jianghu, but has a high crew requirement and its orientation to ASW may not fit Pakistani tactical demands. A comparable prospect to the Luda III is the Project 052 Luhu class (see report). While the Luhu class would be a powerful addition to the Pakistani fleet, technical problems with the design are slowing construction to a crawl. The final option is the F-25T Naresuan class.

There are several other likely export customers. Egypt is one, with a possible order for two or four ships to replace the existing fleet of very old ex-British and ex-Soviet construction. Bangladesh is another possibility; here the existing fleet consists of old British frigates which have large crew requirements and aging hulls. This is a case where the F25T would represent a qualitative advance and possible reductions in expenditures. Burma, Vietnam, Cambodia, and the Philippines have all expressed interest in the design.

The following forecast is based on the placing of a limited number of export orders for F25T design ships. We believe that the pattern will be for small orders of two or three hulls from countries without the resources to buy more advanced ships. We are also projecting a steady two-ship-per-year run from about 1998 onward to replace the Jianghu class.

Ten-Year Outlook