Editing Frigate (section)

====Guided-missile role====
[[File:USS Leahy (CG-16) at sea off San Diego, in May 1978.jpg|thumb|right|{{USS|Leahy|DLG-16|6}} departing [[San Diego, California|San Diego]], California, in May 1978. She was classified as a guided-missile frigate (DLG-16) until 1975, when she was reclassified as a [[guided-missile cruiser]] (CG-16).]]
[[File:Arg 902.jpg|thumb|[[Algerian National Navy]] {{sclass|Koni|frigate|2}} ''[[Algerian frigate Rais Kellik|Rais Kellik]]'']]
[[File:Almirante Blanco Encalada (FF-15).jpg|thumb|The [[Chilean Navy]] {{sclass|Karel Doorman|frigate|2}} ''Almirante Blanco Encalada'', this class is also operated in Netherland, Belgium and Portugal.]]The introduction of the [[surface-to-air missile]] after World War II made relatively small ships effective for anti-aircraft warfare: the "guided-missile frigate". In the USN, these vessels were called "[[ocean escort]]s" and [[hull classification symbol|designated]] "DE" or "DEG" until 1975 – a holdover from the World War II [[destroyer escort]] or "DE". While the [[Royal Canadian Navy]] used similar designations for their warships built in the 1950s, the British [[Royal Navy]] maintained the use of the term "frigate"; in the 1990s the RCN re-introduced the frigate designation.  Likewise, the French Navy refers to missile-equipped ships, up to cruiser-sized ships ({{sclass|Suffren|frigate|5}}, {{sclass|Tourville|frigate|5}}, and {{sclass2|Horizon|frigate|4}}es), by the name of "frégate", while smaller units are named ''[[aviso]]''. The Soviet Navy used the term "guard-ship" (''сторожевой корабль'').

From the 1950s to the 1970s, the [[United States Navy]] commissioned ships classed as guided-missile frigates ([[hull classification symbol]] DLG or DLGN, literally meaning guided-missile [[destroyer leader]]s), which were actually anti-aircraft warfare [[cruiser]]s built on [[destroyer]]-style hulls. These had one or two twin launchers per ship for the [[RIM-2 Terrier]] missile, upgraded to the [[RIM-67 Standard]] ER missile in the 1980s. This type of ship was intended primarily to defend aircraft carriers against anti-ship [[cruise missile]]s, augmenting and eventually replacing converted World War II cruisers (CAG/CLG/CG) in this role. The guided-missile frigates also had an anti-submarine capability that most of the World War II cruiser conversions lacked. Some of these ships – {{USS|Bainbridge|CGN-25|2}} and {{USS|Truxtun|CGN-35|2}} along with the {{sclass|California|cruiser|5}} and {{sclass|Virginia|cruiser|4}}es – were [[United States naval reactors|nuclear-powered]] (DLGN).{{sfnp|Bauer|Roberts |1991|pp=215–217}} These "frigates" were roughly mid-way in size between cruisers and destroyers. This was similar to the use of the term "frigate" during the age of sail during which it referred to a medium-sized warship, but it was inconsistent with conventions used by other contemporary navies which regarded frigates as being smaller than destroyers. During the [[United States Navy 1975 ship reclassification|1975 ship reclassification]], the large American frigates were redesignated as guided-missile cruisers or destroyers (CG/CGN/DDG), while [[ocean escort]]s (the American classification for ships smaller than destroyers, with hull symbol DE/DEG ([[destroyer escort]])) such as the ''[[Knox-class frigate|Knox]]''-class were reclassified as frigates (FF/FFG), sometimes called "fast frigates". In the late 1970s, as a gradual successor to the ''Knox'' frigates, the US Navy introduced the 51-ship {{sclass|Oliver Hazard Perry|frigate|0}} guided-missile frigates (FFG), the last of which was decommissioned in 2015, although some serve in other navies.{{sfnp|Bauer|Roberts|1991|pp=251–252}} By 1995 the older guided-missile cruisers and destroyers were replaced by the {{sclass|Ticonderoga|cruiser|1}}s and {{sclass|Arleigh Burke|destroyer|1}}s.{{sfnp|Gardiner|Chumbley|1995|pp=580–585}}

One of the most successful post-1945 designs was the British {{sclass|Leander|frigate|2}}, which was used by several navies. Laid down in 1959, the ''Leander'' class was based on the previous [[Whitby-class frigate|Type 12 anti-submarine frigate]] but equipped for anti-aircraft use as well. They were used by the UK into the 1990s, at which point some were sold onto other navies. The ''Leander'' design, or improved versions of it, were licence-built for other navies as well. Nearly all modern frigates are equipped with some form of offensive or defensive missiles, and as such are rated as guided-missile frigates (FFG). Improvements in surface-to-air missiles (e.g., the [[Eurosam]] [[MBDA Aster|Aster 15]]) allow modern guided-missile frigates to form the core of many modern navies and to be used as a fleet defence platform, without the need for specialised anti-air warfare frigates.
[[File:INS Nilgiri firing Brahmos.jpg|thumb|[[INS Nilgiri (2019)|INS ''Nilgiri'']] firing [[BrahMos]].]]
Modern destroyers and frigates have sufficient endurance and seaworthiness for long voyages and so are considered [[Blue-water navy|blue water]] vessels, while [[corvette]]s (even the largest ones capable of carrying an [[anti-submarine warfare]] helicopter) are typically deployed in coastal or [[littoral zone]]s so are regarded as [[Brown-water navy|brown-water]] or [[Green-water navy|green-water]] vessels.<ref>{{cite web|url=https://navalpost.com/what-is-the-difference-between-frigate-and-destroyer/ |title=Question: What is the difference between Frigate and Destroyer? - Naval Post- Naval News and Information |publisher=Naval Post |date= 7 March 2021|accessdate=2022-08-03}}</ref> According to Dr. Sidharth Kaushal of the Royal United Services Institute for Defence and Security Studies, describing the difference between 21st century destroyers and frigates, the larger "destroyers can more easily carry and generate the power for more powerful high-resolution radar and a larger number of vertical launch cells. They can thus provide theatre wide air and missile defence for forces such as a carrier battle group and typically serve this function". By contrast the smaller "frigates are thus usually used as escort vessels to protect sea lines of communication or as an auxiliary component of a strike group". The largest and powerful destroyers are often classified as cruisers, such as the {{sclass|Ticonderoga|cruiser|1}}s, due to their extra armament and facilities to serve as fleet flagships.<ref>{{cite web |url=https://www.naval-technology.com/analysis/frigate-vs-destroyer-difference/ |title=Frigate vs destroyer: What is the difference between the two warships? |publisher=Naval-technology.com |date=24 April 2019 |accessdate=2022-08-03 |archive-date=12 July 2022 |archive-url=https://web.archive.org/web/20220712094835/https://www.naval-technology.com/analysis/frigate-vs-destroyer-difference/ |url-status=dead }}</ref>