tungsten alloy and Nilgiri [Leander] Class Frigate

The Nilgiri class frigates of the Indian Navy are updated versions of the Leander class, designed and built for the Indian Navy by Mazagon Dock Limited in Mumbai. Six ships have been built between 1972-81. The last two vessels (F41, F42) have more powerful engines than the remainder. Vessels of the class form the 14th Frigate Squadron. The Nilgiri class and its lead ship, 

INS Nilgiri are all named for the Nilgiri Hills. Subsequent ships of the class are also named for hill ranges of India. The Nilgiri class will be decommissioned by the Navy. Four ships from the class have been decommissioned, with the remainder being used primarily for training and testing roles. These will be decommissioned by 2009-10, once the Shivalik class vessels enter service. 

The Nilgiri Class frigates served as the mainstay & workhorse of the Indian Navy during the 1980s and early 1990s and they formed the 14th Frigate Squadron. The last two vessels (F41, F42) have more powerful engines than the remainder. INS Taragiri (F41) had a serious fire in July 1994, but was repaired and was back in active service in 1995. Westinghouse supplied the Indian Navy 

with ASW sonar systems, two hull mounted arrays and three visible depth sonar arrays which are installed inside towed bodies built by Fathom Ocean Ltd. Transducer elements in both cases are identical. INS Udaygiri (F35) underwent a refit at Naval Dockyard, Mumbai. The remaining vessels in the series were expected to have their armaments brought into line with later ships.
 

INS Himgiri (F34) was used as a trial ship for the indigenous APSOH (Advanced Panoramic Sonar Hull) sonar.

Name	Pennant	Commissoned	Decommissioned	Comments
INS Nilgiri	F33	23rd June 1972	1996	Sunk on 24 April 1997, by a Sea Eagle AShM fired from a Sea Harrier Frs Mk.51 of the Indian Navy from INS Viraat.
INS Himgiri	F34	23 November 1974	06 May 2005	The vessel holds the distinction of having the maximum number of days at sea in single commission and was the first to shoot down a pilotless aircraft in 1976. Captain K N Zadu, VrC, (Retd.) who served as her first commanding officer, was the chief guest at the decommissioning ceremony along with Commander Ravneet Singh who served as her last commanding officer.
INS Udaygiri	F35	18 February 1976	24 August 2007
INS Dunagiri	F36	5 May 1977		Named after one of the Himalayan peaks. Her crest depicts the Osprey, a Himalayan bird and the ship's motto is 'Victory Is My Profession'. On 27 September 2006 INS Dunagiri collided with a merchant vessel, MV Kiti, 30 nautical miles off the Mumbai coast. The vessel was returning to port after a joint navy-air force exercise practicing the defending of coast of Gujarat ended ahead of schedule as a result of a cyclone warning, when it rammed into a merchant vessel MV Kiti. The merchant vessel, which was en route to Colombo,Sri Lanka, apparently misread the navigational line of INS Dunagiri. The incident, which happened on the busy fishing lanes off Mumbai left bow of INS Dunagiri damaged and she was dry-docked for repairs. Commander Atul Nag, the commanding officer of INS Dunagiri, was questioned in the incident and a Board of Inquiry was set up to determine the cause of the accident.Westinghouse supplied the Indian Navy with ASW sonar systems, these include two hull mounted arrays and three visible depth sonar arrays which are installed inside towed bodies built by Fathom Ocean Ltd. Transducer elements in both cases are identical. The Udaygiri has underwent a refit at Naval Dockyard, Mumbai. The remaining vessels in the series were expected to have their armaments brought into line with later ships. It has not been reliably confirmed through official channels, whether this has actually occurred.
INS Taragiri	F41	16 May 1980		Named after a hill range in Garhwal Himalayas in Northern India. INS Taragiri had a serious fire in July 1994, but was repaired and was back in active service in 1995.
INS Vindhyagiri	F42	08 July 1981