The Delhi-class destroyers are guided-missile destroyers of the Indian Navy. Three ships of this class are in active service. The Delhi-class vessels were the largest vessels to be built in India at the time of their commissioning. The ships were built by Mazagon Dock Limited at a cost of each.
Development
The design and development of the ship class began as "Project 15" in 1980. Initially, the ships were planned to be follow-on frigates of the with the addition of RBU-6000ASWrocket launchers and gas turbine propulsion. A Soviet offer in 1983 for reversible gas turbines and modern weapon systems forced a redesign of the ships from 3,500 tonne frigates to 6,300 tonne destroyers. Directorate of Naval Design completed the design around the mid 1980s. Model tests were carried out at SSPA, Sweden in 1985 and parallelly at Krylov Institute, Soviet Union in 1986. Severnoye Design Bureau provided design inputs for weapons and propulsion packages. The mutual interface suppression system for electromagnetic compatibility was supplied by the Soviets. The break-up of Soviet Union affected the supply of weapon systems, contributing to a three-year delay in the construction of vessels.
Design and description
Delhi class has been described as a stretched with some elements incorporated from Godavari-class frigates and s. The fore funnel is placed on the port side, while the aft funnel is placed on the starboard. The propulsion system consists of two Zorya-Mashproekt M36E gas turbine plants driving two controllable-pitch propellers. Each gas turbine plant comprises two DT-59 reversible gas turbines connected to an RG-54 gearbox in a combined gas and gas system and is placed in a separate engine room. The vessels are equipped for operation in a nuclear, biological and chemical warfare environment. Delhi-class vessels are fitted with flag facilities, enabling them to act as command unit in task groups. features better air conditioning facilities to correct heat dissipation issues encountered while operationalising.
Armament
For air defence role Delhi class is fitted with 9K-90 Uraganair-defence system comprising a pair of 3S-90 single-arm launchers and 9M38M1 Shtil missiles. One launcher is installed forward of the bridge and the other atop the dual helicopter hangar. Each launcher carries a 24 missile magazine for a total of 48 rounds. MR-775 Fregat-MAE radar provides target designation and 6 MR-90 Orekh illuminators are used for fire control. The system can track twelve targets and engage a maximum of six tracked targets simultaneously. Last-ditch missile defence is provided by a close-in weapon systemconsisting of four AK-630 rotary cannons guided by two MR-123-02 fire-control radars. A Signaal LW08 radar license produced by BEL as RAWL provides long range air search capability. The surface missile battery of Delhi class includes 16 Kh-35E Uran missiles placed in four quadruple sloped launchers. The missiles are guided by a Granit Garpun B fire-control radar. The missile battery was initially intended to be eight 3M80E Moskit cruise missiles as evidenced by large blast deflectors present on the lead ship, INS Delhi. A single AK-100 gun guided by MR-184 fire-control system is also fitted. A quintuple trainable torpedo launcher capable of firing SET 65E active/passive homing torpedo and Type 53–65 wake homing torpedo is placed in between the funnels. A pair of 12-tubed RBU-6000 213mm anti-submarine rocket launchers fitted in front of the bridge can engage submarines up to a range of. Detection is provided by BEL HUMVAD, an indigenous hull-mounted sonar with a variable depth transducer that offers better performance in the waters around India. An Indal Model 15-750 handling system manufactured by GRSE is used to deploy the variable depth sonar of HUMVAD. The final ship of the class,, is fitted with an improved ASW suite consisting of BEL HUMSA hull-mounted sonar and Thales ATAS towed array sonar. The electronic warfare suite consists of BEL Ajanta Mk 2 for electronic support measures, Elettronica TQN-2 jammer and two PK-2 chaff launchers of Russian origin. BEL Shikari combat display and management system, a derivative of Italian IPN-10, integrates weapon systems of diverse origin. Each vessel can carry two Westland Sea King Mk 42B helicopters. The helicopters carry a surface search radar, a dipping sonar, A244-S lightweight torpedoes and Sea Eagleanti-ship missiles. Samahé helicopter handling system is fitted on all vessels.
Modernisation
The Delhi class is being upgraded with the IAI/Rafael Barak 1point air defence missile system. A pair of eight-cell vertical launch system replaces two AK-630 mounts in front of the aft mast. The missiles have a range of and use command line-of-sight guidance provided by a pair of EL/M-2221 fire-control radars that replace MR-123-02 fire-control radars on upgraded ships. An upgrade to BrahMos supersonic missiles was sanctioned in 2015. Atlas Elektronik ACTAS towed-array sonar will also be installed on all three ships.
