Editing Delhi-class destroyer (section)

==Design and description==

The ''Delhi'' class has been described as a stretched {{sclass|Rajput|destroyer|4}} with some elements incorporated from ''Godavari''-class frigates and {{sclass|Sovremennyy|destroyer|2}}s.<ref name="jfs-0405"/><ref name="miltech-nov04">{{cite journal|last=Annati|first=Massimo|date=November 2004|volume=28|issue=11|title=The Asian DDG Race|url=https://www.proquest.com/docview/199087688|journal=Military Technology|url-access=subscription|pages=31–39|location=Bonne|publisher=Mönch Publishing Group|issn=0722-3226|oclc=137343253|id={{ProQuest|199087688}}|archive-date=8 September 2023|access-date=17 April 2022|archive-url=https://web.archive.org/web/20230908044418/https://www.proquest.com/docview/199087688|url-status=live}}</ref> The fore [[Funnel (ship)|funnel]] is placed on the port side, while the aft funnel is placed on the starboard.<ref name="jfs-0405"/> The propulsion system consists of two [[Zorya-Mashproekt]] M36E gas turbine plants driving two [[Variable-pitch propeller (marine)|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.<ref name="miltech-nov04"/> The vessels are equipped for operation in a [[nuclear, biological and chemical warfare]] environment.<ref name="jdw-17sep97"/> ''Delhi''-class vessels are fitted with flag facilities, enabling them to act as command unit in task groups.<ref name="miltech-nov04"/> {{INS|Mysore|D60|6}} features better air conditioning facilities to correct heat dissipation issues encountered while operationalising {{INS|Delhi|D61|6}}.<ref>{{cite journal |title=Indian destroyer set for commission |journal=Jane's International Defense Review |date=1 April 1999 |volume=32 |issue=4 |publisher=Jane's Information Group |location=Coulsdon |issn=1476-2129}}</ref>

===Armament===

For air defence role, ''Delhi'' class is fitted with [[Buk missile system#Naval versions|9K-90 ''Uragan'']] (NATO: SA-N-7 Gadfly) [[Anti-aircraft warfare|air-defence]] system comprising a pair of 3S-90 single-arm launchers and [[Buk missile system#9М38 and 9М38M1 missile|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 {{convert|35|–|40|km}} range and feature [[semi-active radar homing]]. MR-775 Fregat-MAE ([[NATO reporting name|NATO]]: Half Plate) radar provides target designation and six MR-90/3R-90 ''Orekh'' (NATO: Front Dome) illuminators are used for fire control.<ref name="miltech-nov04"/><ref name="seaforth-2011"/> The system can track twelve targets and engage a maximum of six tracked targets simultaneously.<ref name="miltech-sep98">{{cite journal|last=Khan|first=M A|date=September 1998|volume=22|issue=9|title=DELHI and beyond|url=https://www.proquest.com/docview/199041413|journal=Military Technology|url-access=subscription|pages=68–70|location=Bonne|publisher=Mönch Publishing Group|issn=0722-3226|oclc=137343253|id={{ProQuest|199041413}} }}</ref> 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 {{convert|10|km|abbr=on}} and use [[Command guidance#Command to Line-Of-Sight (CLOS)|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 [[Bharat Electronics Limited|BEL]] as RAWL provides long range air search capability.<ref name="miltech-nov04"/>

The surface missile battery of ''Delhi'' class includes 16 [[Kh-35|Kh-35E ''Uran'']] missiles placed in four quadruple sloped launchers. The missiles feature [[active radar homing]] and are guided by a Granit Garpun B (NATO: Plank Shave) fire-control radar. They have a maximum range of {{convert|130|km}} and are capable of [[sea skimming]].<ref name="jfs-0405"/> The missile battery was initially intended to be eight [[P-270 Moskit|3M80E ''Moskit'']] cruise missiles as evidenced by large blast deflectors present on the lead ship, INS ''Delhi''. A single [[AK-100 (naval gun)|AK-100]] gun guided by MR-184/MR-145 fire-control system (NATO: Kite Screech), which comprises T-91E radar and Kondensor electro-optical sights, was originally fitted to the ships.<ref name="miltech-nov04"/><ref name="seaforth-2011">{{cite book |last1=Mazumdar |first1=Mrityunjoy |editor1-last=Waters |editor1-first=Conrad |title=Seaforth World Naval Review 2011 |date=2010 |publisher=Seaforth |location=Barnsley |isbn=978-1848320758 |pages=102–119}}</ref> The three ships have replaced the 100mm guns with [[OTO Melara 76 mm]] naval gun during refits in the early 2020s.

{{multiple image|perrow=2/2|total_width=360|caption_align=center
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| title =
| image1 = D61 INS Delhi Fregat-MAE 3D Radar Vladivostok.jpg
| image2 = D61 INS Delhi RALW Early Warning Radar Vladivostok 2011-04-19.jpg
| image3=  D61 INS Delhi 3S-90 Aft Launcher (Shtil AAW) Vladivostok 2011-04-19.jpg
| image4 = D61 INS Delhi RBU-6000 ASW Launcher Vladivostok 2011-04-19.jpg
| footer = {{font|size=110%|font=Sans-serif|text=Weapons and sensors fitment on Delhi-class.<br />(top) Fregat-MAE E-band radar, [[Bharat Electronics|BEL]] RAWL LW08, [[Buk missile system|Shitil-1]] SAM system, [[Larsen & Toubro|L&T]] [[RBU-6000]] ASW rocket launcher.}}
}}

A quintuple {{convert|21|in|mm|adj=on|order=flip|0}} trainable torpedo launcher capable of firing SET 65E active/passive homing torpedo and [[Type 53 torpedo|Type 53–65]] wake homing torpedo is placed in between the funnels.<ref>{{cite web|title=MDL's Major Programmes – SP's Naval Forces|url=http://www.spsnavalforces.com/story/?id=278|website=SP's Naval Forces|publisher=SP Guide Publications|language=en|date=September 2013}}</ref><ref name="jfs-0405"/> 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 {{convert|6|km|abbr=on}}.<ref name="miltech-sep98"/><ref name="jfs-0405"/> 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.<ref name="miltech-sep98"/> An Indal Model 15-750 handling system manufactured by [[GRSE]] is used to deploy the variable depth sonar of HUMVAD.<ref name="jni-1sep97">{{cite magazine|date=1 September 1997|title=India {{!}} First Project 15 set to commission|magazine=Jane's Navy International|location=Coulsdon|publisher=Jane's Information Group|issn=1358-3719}}</ref> The final ship of the class, {{INS|Mumbai}}, is fitted with an improved ASW suite consisting of BEL HUMSA hull-mounted sonar and Thales ATAS towed array sonar.<ref name="miltech-nov04"/>

The electronic warfare suite originally consisted of BEL Ajanta Mk 2 for [[electronic support measures]], Elettronica TQN-2 jammer and two PK-2 chaff launchers of Russian origin.<ref name="jfs-0405"/> The Ajanta Mk 2 system was later<!--Date is not provided in the source--> replaced by Ellora, which has an additional capability to provide [[electronic countermeasures]].<ref name="seaforth-2011"/> BEL Shikari combat display and management system, a derivative of Italian IPN-10, integrates weapon systems of diverse origin.<ref name="miltech-nov04"/> 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 Eagle (missile)|Sea Eagle]] anti-ship missiles.<ref name="miltech-sep98"/> Samahé helicopter handling system is fitted on all vessels.<ref name="jfs-0405"/>

=== Modernisation ===
[[File:The_BrahMos_missile_fired_from_an_upgraded_modular_launcher_on_INS_Delhi_on_20_April_2022_-_1.jpg|thumb|213x213px|[[INS Delhi (D61)|INS Delhi]] 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 (anti-missile system)|Kavach]] decoy launchers.<ref>{{cite web |last1=Mazumdar |first1=Mrityunjoy |title=Details emerge on INS Mumbai upgrade |url=https://www.shephardmedia.com/news/naval-warfare/details-emerge-ins-mumbai-upgrade/ |website=Shephard |access-date=17 April 2022 |language=en |date=29 April 2020}}</ref><ref>{{cite news|title=Nod to new aircraft carrier, BrahMos missiles for six ships|url=http://www.business-standard.com/article/news-ians/nod-to-new-aircraft-carrier-brahmos-missiles-for-six-ships-115051301785_1.html|work=Business Standard|agency=IANS|date=13 May 2015}}</ref> Atlas Elektronik ACTAS towed-array sonar will be installed on all three ships.<ref>{{cite news|last1=Shukla|first1=Ajai|title=Sonar contract provides major boost to navy|url=http://www.business-standard.com/article/economy-policy/sonar-contract-provides-major-boost-to-navy-114112500024_1.html|work=Business Standard|date=25 November 2014|location=New Delhi|archive-date=29 December 2017|access-date=29 December 2017|archive-url=https://web.archive.org/web/20171229172043/http://www.business-standard.com/article/economy-policy/sonar-contract-provides-major-boost-to-navy-114112500024_1.html|url-status=live}}</ref> In April 2022, Brahmos missile was tested from [[INS Delhi (D61)|INS ''Delhi'']] with new modular slant launcher design.<ref>{{Cite web |date=20 April 2022 |title=BrahMos missile successfully tested from Navy's INS Delhi, IAF's Sukhoi-30 MKI |url=https://indianexpress.com/article/india/brahmos-missile-succesfully-tested-navy-ins-delhi-iaf-sukhoi-30-mki-7877736/ |access-date=3 July 2022 |website=The Indian Express |language=en |archive-date=3 July 2022 |archive-url=https://web.archive.org/web/20220703080755/https://indianexpress.com/article/india/brahmos-missile-succesfully-tested-navy-ins-delhi-iaf-sukhoi-30-mki-7877736/ |url-status=live }}</ref><ref>{{Cite web |title=Watch: Successful maiden BrahMos firing by INS Delhi from an upgraded modular launcher |url=https://economictimes.indiatimes.com/news/defence/watch-successful-maiden-brahmos-firing-by-ins-delhi-from-an-upgraded-modular-launcher/videoshow/90943024.cms |access-date=19 Apr 2022 |website=The Economic Times |date=19 April 2022 |language=en}}</ref>

===Relocation===

The ''Delhi''-class destroyers will be re-based to the [[Eastern Naval Command]], [[Visakhapatnam]]. Along with {{sclass|Nilgiri|frigate|4||2019}}, these will form a part of the carrier battle group of {{INS|Vikrant|2013|6}}. {{INS|Mysore|D60|2}} had reached its new base by December 2021 and was undergoing refit.<ref name="delh-rebase">{{cite web |last=Bhattacharjee |first=Sumit |date=2021-12-04 |title=Eastern Fleet will have Carrier Battle Group: Vice Admiral |url=https://www.thehindu.com/news/national/andhra-pradesh/eastern-fleet-will-have-carrier-battle-group-vice-admiral/article37833874.ece/amp/ |work=The Hindu}}</ref>