Delhi-class destroyer

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-6000 ASW rocket 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. The 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 the Soviet Union affected the supply of weapon systems, contributing to a three-year delay in the construction of vessels. ==Design and description==

The 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. Armament For air defence role, Delhi class is fitted with 9K-90 Uragan (NATO: SA-N-7 Gadfly) air-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. The missiles have range and feature semi-active radar homing. MR-775 Fregat-MAE (NATO: Half Plate) radar provides target designation and six MR-90/3R-90 Orekh (NATO: Front Dome) illuminators are used for fire control. Last-ditch missile defence is provided by AK-630-based close-in weapon system. As of 2024, all three vessels of the class have been upgraded with an additional IAI/Rafael Barak 1 point defence missile system. Originally four AK-630 rotary cannons surrounding the aft mast, which are guided by two MR-123-02 (NATO: Bass Tilt) fire-control radars were installed but after Midlife Refit, the two AK-630 mounts ahead of the aft mast have each been replaced by pair of eight-cell Barak 1 vertical launch systems, for a total of 32 missiles. 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. A Signaal LW08 radar license produced by BEL as RAWL provides long range air search capability. The three ships have replaced the 100mm guns with OTO Melara 76 mm naval gun during refits in the early 2020s. 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. 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. fires BrahMos missile As of January 2024, INS Delhi (D61) and INS Mumbai (D62) has completed their mid-life refit that includes upgrades for several weapons and sensors. The Kh-35E Uran missiles has been replaced by BrahMos missiles, which was originally sanctioned in 2015 for two ships of this class. The primary radar has been replaced with Fregat M2EM radar from the older MR-755 Fregat-MAE. The AK-100 main gun has been replaced by OTO Melara 76 mm along with BEL Lynx U2 FCR. The electronics warfare system is upgraded to Ellora Mk II, with Kavach decoy launchers. Atlas Elektronik ACTAS towed-array sonar will be installed on all three ships. In April 2022, Brahmos missile was tested from INS Delhi with new modular slant launcher design. Relocation The Delhi-class destroyers will be re-based to the Eastern Naval Command, Visakhapatnam. Along with , these will form a part of the carrier battle group of . had reached its new base by December 2021 and was undergoing refit. ==Ships of the class==