Feature 3 | DESTROYERS, FRIGATES & CORVETTES


Vietnam commissions Gepard light frigate


Te Vietnamese Navy commissioned the first of two Project 11661 Gepard 3.9 light frigates, Dinh Tien Hoang, on 5 March 2011.


T


he second frigate, Yard No. 955, which has been conducting trials from the Baltic seaport of Kronstadt,


is due to be transported to Vietnam aboard a heavy-liſt ship shortly. Te two corvettes, or light frigates, were


built under a December 2006 contract (believed to be worth around US$350 million) awarded to Zelenodolsk (AM Gorky)


shipyard in Tatarstan, Russia,


Rosboronexport by the Vietnamese Government. Te lead ship was laid down on 10 July


2007, the second on 28 November 2007. Te first vessel was launched on 12 December 2009, followed by the second in mid-March 2010. Tey were then towed to Kronstadt in July-August 2010 for outfitting. Sea trials for the first vessel commenced on 25 October 2010, followed by delivery to the Vietnamese in late December 2010. Though the Gepard 3.9 is based on


a Russian Navy Pr.11661K design, the Vietnamese vessels have been designed to specific Vietnamese requirements by Zelenodolsk Design Bureau (ZPKB). Notably, they feature a stealthy superstructure, organic helicopter facilities – a first for the Vietnamese Navy – and more advanced weapons and hull systems. Te circa 2100tonne light frigates have


an overall length of 102.2m, a beam of approximately 14m and a draſt of around 3.7m. Te design complement is 84 including an air group of eight. Largely constructed from steel, the masts,


funnel and hull recesses are made from an aluminium-magnesium alloy to save topside weight. For damage control,


there are


three fire fighting zones and 10 watertight compartments – such that if two adjacent compartments are flooded, the vessel will still float. Operations in a NBC (nuclear, biological, chemical) environment are possible because of a collective protection zone which seals off the main living and control centers from NBC fallout.


24 The Combined Diesel or Gas-turbine


(CODOG) propulsion system has a total propulsive power of around 40,000hp. Two Zorya Mashproekt DO-90 reversible gas turbines (each rated at 19,500hp) and a Kolomna 86Bdiesel (rated at 8000hp) drive two fixed-pitch propellers. Te diesel is cross-connected to the two gas turbine gearboxes for operational flexibility. Te diesel can drive both shaſts for cruising or one turbine can drive both shaſts or both turbines can drive both shaſts when rapid acceleration is required. The gas turbine exhaust gases have infra-red suppression devices, and the exhaust gases are cooled by sea water and discharged near the waterline. A bow thruster is also fitted to permit


alongside manoeuvring without tugs, and the hull has twin bilge keels and fin stabilizers. Te machinery control is from the main machinery control room as well as local control panels. The new vessels have a maximum speed of around 29knots. Cruising speed on diesels is thought to be around 21knots, considerably higher than the 18knots of the Russian Navy versions. Range is 5000nm at 10knots while endurance is 20 days. Electrical power is provided by four 500kW generators grouped in the bow and stern areas as well as an emergency 100kW set located elsewhere. Te armament on the Vietnamese vessels


includes a single 76mm AK-176M main gun, a Palma gun-missile mount with Sosna-R missiles, two 30mm AK-630M Gatling


guns, two quad launchers for Uran-E anti- ship missiles, the Paket-E/ NK anti-torpedo system with two hull-mounted quad launchers for 324mm homing torpedoes. In addition, two MTPU 14.5mm heavy machine guns, two PKMB 7.62mm light machine guns, shoulder-launched Igla surface-to-air missiles and DP-64 grenade launchers are also fitted. Te ships can also carry mines. Te sensor suite comprises a Positiv ME1


3-D air/surface search radar, a Mineral ME radar in an enclosed radome, the 67R IFF suite with two antennae, a MR-231 navigation radar, a 5P-10-03E radar with an electro-optic capability. Underwater sensors are a hull-mounted MGK-335EM-03 sonar and, it is believed, the Anapa-ME diver detection sonar for use with the DP-64 grenade launchers. Te electronic warfare suite comprises the MP-405-1E system as well as four PK10 decoy launchers. These ships have an integrated bridge


system and a Sigma-E combat management system. They embark a 12tonne Kamov Ka-28/31 helicopter. Te below decks hangar is accessed through a recessed opening that is part of a mast structure. Te status of a follow-on order for two


additional units is not clear. Russian media reports have suggested these could be constructed in Vietnam using material packages supplied from Russia. The frigates will replace four 1960’s


vintage Project 159 Petya II/III class light frigates. WT


Warship Technology May 2011


Dinh Tien Hoang was commissioned into the Vietnamese Navy in March (photo: Zelenodolsk Shipyard).


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