Editing Frigate (section)

==Modern era==
===World War II===
{{See also|List of frigates of World War II}}
[[File:Lochmorlich.jpg|thumb|A {{sclass2|Loch|frigate|1}}]]
[[File:USS Gallup (PF-47).jpg|thumb|The U.S. Navy {{sclass|Tacoma|frigate|0}} patrol frigate {{USS|Gallup|PF-47|6}} at [[San Pedro, California|San Pedro]], [[California]], on 30 May 1944]]

Modern frigates are related to earlier frigates only by name. The term "frigate" was readopted during the [[World War II|Second World War]] by the British [[Royal Navy]] to describe an [[Anti-submarine warfare|anti-submarine]] escort vessel that was larger than a [[corvette]] (based on a mercantile design), while smaller than a [[destroyer]]. The vessels were originally to be termed "twin screw corvettes" until the Royal Canadian Navy suggested to the British re-introducing the term "frigate" for the significantly enlarged vessels.  Equal in size and capability to the American [[destroyer escort]], frigates are usually less expensive to build and maintain.<ref>{{cite web|url=http://www.military-today.com/navy/top_10_frigates.htm|title=Top 10 Frigates {{!}} Military-Today.com|last=ARG|website=www.military-today.com|access-date=2017-07-13|archive-url=https://web.archive.org/web/20170629102103/http://www.military-today.com/navy/top_10_frigates.htm|archive-date=29 June 2017|url-status=usurped}}</ref> Small anti-submarine escorts designed for naval use from scratch had previously been classified as [[Sloop-of-war|sloops]] by the Royal Navy, and the {{sclass|Black Swan|sloop|2}}s of 1939–1945 (propelled by steam turbines as opposed to cheaper triple-expansion steam engines) were as large as the new types of frigate, and more heavily armed. 22 of these were reclassified as frigates after the war, as were the remaining 24 smaller {{sclass2|Castle|corvette|2}}s.

The frigate was introduced to remedy some of the shortcomings inherent in the {{sclass2|Flower|corvette|0}} corvette design: limited armament, a hull form not suited to open-ocean work, a single [[driveshaft|shaft]] which limited speed and maneuverability, and a lack of range. The frigate was designed and built to the same mercantile construction standards ([[scantling]]s) as the corvette, allowing manufacture by yards unused to warship construction. The first frigates of the {{sclass2|River|frigate|4}} (1941) were essentially two sets of corvette machinery in one larger hull, armed with the latest [[Hedgehog (weapon)|Hedgehog]] anti-submarine weapon.

The frigate possessed less offensive firepower and speed than a [[destroyer]], including an [[escort destroyer]], but such qualities were not required for anti-submarine warfare. Submarines were slow while submerged, and [[ASDIC]] sets did not operate effectively at speeds of over {{convert|20|kn|mph km/h|lk=on}}. Rather, the frigate was an austere and weatherly vessel suitable for mass-construction and fitted with the latest innovations in anti-submarine warfare. As the frigate was intended purely for convoy duties, and not to deploy with the fleet, it had limited range and speed.

It was not until the Royal Navy's {{sclass2|Bay|frigate|4}} of 1944 that a British design classified as a "frigate" was produced for fleet use, although it still suffered from limited speed. These [[Anti-aircraft warfare|anti-aircraft]] frigates, built on incomplete {{sclass2|Loch|frigate|2}} hulls, were similar to the [[United States Navy]]'s destroyer escorts (DE), although the latter had greater speed and offensive armament to better suit them to fleet deployments. The destroyer escort concept came from design studies by the [[General Board of the United States Navy]] in 1940, as modified by requirements established by a British commission in 1941{{sfnp|Gardiner|1980 |p=149}} prior to the American entry into the war, for deep-water escorts. The American-built destroyer escorts serving in the [[United Kingdom|British]] [[Royal Navy]] were rated as [[Captain-class frigate|Captain-class]] frigates. The U.S. Navy's two [[Canada|Canadian]]-built {{sclass|Asheville|frigate|0}} and 96 British-influenced, American-built {{sclass|Tacoma|frigate|0}} frigates that followed originally were classified as "patrol [[gunboat]]s" (PG) in the U.S. Navy but on 15 April 1943 were all reclassified as '''patrol frigates (PF)'''.

===Modern frigate===
====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>

====Other uses====
The Royal Navy [[Salisbury-class frigate|Type 61 (''Salisbury'' class)]] were [[radar picket|"air direction"]] frigates equipped to track aircraft. To this end they had reduced armament compared to the [[Leopard-class frigate|Type 41 (''Leopard''-class)]] air-defence frigates built on the same hull. Multi-role frigates like the [[MEKO 200]], {{sclass|Anzac|frigate|5}} and {{sclass|Halifax|frigate|4}}es are designed for navies needing warships deployed in a variety of situations that a general frigate class would not be able to fulfill and not requiring the need for deploying [[destroyer]]s.{{citation needed|date=July 2022}}

====Anti-submarine role====
{{See also|anti-submarine warfare}}

[[File:HMS Somerset (F82).jpg|thumb|right|{{HMS|Somerset|F82|6}} of the [[Royal Navy]]. [[Type 23 frigate]]s were built for [[anti-submarine warfare]] but are capable multi-purpose ships.<ref>{{cite web |title=Type 23 Frigates |url=http://www.royalnavy.mod.uk/operations-and-support/surface-fleet/type-23-frigates/ |archive-url=https://web.archive.org/web/20100531045448/http://www.royalnavy.mod.uk/operations-and-support/surface-fleet/type-23-frigates/ |archive-date=31 May 2010 |url-status=dead |website=Royal Navy website}}</ref>]]
At the opposite end of the spectrum, some frigates are specialised for [[anti-submarine warfare]]. Increasing submarine speeds towards the end of World War II (see [[German Type XXI submarine]]) greatly reduced the margin of speed superiority of frigate over submarine. The frigate could no longer be slow and powered by mercantile machinery and consequently postwar frigates, such as the {{sclass|Whitby|frigate|4}}, were faster.

Such ships carry improved [[sonar]] equipment, such as the [[variable depth sonar]] or [[towed array sonar|towed array]], and specialised weapons such as [[torpedo]]es, forward-throwing weapons such as [[Limbo (weapon)|Limbo]] and missile-carried anti-submarine torpedoes such as [[ASROC]] or [[Ikara (missile)|Ikara]]. The Royal Navy's original [[Type 22 frigate]] is an example of a specialised anti-submarine warfare frigate, though it also has [[Sea Wolf (missile)|Sea Wolf]] surface-to-air missiles for point defense plus [[Exocet]] surface-to-surface missiles for limited offensive capability.

Especially for anti-submarine warfare, most modern frigates have a [[Helipad|landing deck]] and [[hangar]] aft to operate [[helicopter]]s, eliminating the need for the frigate to close with unknown sub-surface threats, and using fast helicopters to attack nuclear submarines which may be faster than surface warships. For this task the helicopter is equipped with sensors such as [[sonobuoy]]s, wire-mounted dipping sonar and [[magnetic anomaly detector]]s to identify possible threats, and torpedoes or [[depth-charge]]s to attack them.

With their onboard radar helicopters can also be used to reconnoitre over-the-horizon targets and, if equipped with [[anti-ship missile]]s such as [[Penguin missile|Penguin]] or [[Sea Skua]], to attack them. The helicopter is also invaluable for [[search and rescue]] operation and has largely replaced the use of [[dinghy|small boats]] or the [[Underway replenishment|jackstay rig]] for such duties as transferring personnel, mail and cargo between ships or to shore. With helicopters these tasks can be accomplished faster and less dangerously, and without the need for the frigate to slow down or change course.

====Air defence role====
[[File:Danish frigate KDM Niels Juel (F363) underway in the Red Sea on 15 April 2019 (190415-N-IL409-0016).JPG|thumb|{{sclass|Iver Huitfeldt|frigate|4}}]]
Frigates designed in the 1960s and 1970s, such as the US Navy's {{sclass|Knox|frigate|1}}, West Germany's {{sclass|Bremen|frigate|1}}, and Royal Navy's [[Type 22 frigate]] were equipped with a small number of short-ranged surface-to-air missiles ([[AIM-7 Sparrow#Sea Sparrow|Sea Sparrow]] or [[Sea Wolf (missile)|Sea Wolf]]) for point defense only.

By contrast newer frigates starting with the {{sclass|Oliver Hazard Perry|frigate|1}} are specialised for "zone-defense" [[anti-aircraft warfare|air defence]], because of the major developments in [[fighter jet]]s and [[ballistic missile]]s. Recent examples include the {{sclass|De Zeven Provinciën|frigate|0}} air defence and command frigate of the [[Royal Netherlands Navy]]. These ships are armed with [[RIM-66 Standard|VL Standard Missile 2 Block IIIA]], one or two [[Goalkeeper CIWS]] systems, ({{HNLMS|Evertsen|F805|6}} has two Goalkeepers, the rest of the ships have the capacity for another one.) [[RIM-162 ESSM|VL Evolved Sea Sparrow Missile]]s, a special [[SMART-L]] radar and a Thales [[Active Phased Array Radar]] (APAR), all of which are for air defence. Another example is the {{sclass|Iver Huitfeldt|frigate|4}} of the [[Royal Danish Navy]].<ref>{{cite web|url=https://marineschepen.nl/schepen/zeprov.html#specs|title=De Zeven Provinciën classe (LCF)|publisher=Jaime Karreman|access-date=24 September 2018|archive-url=https://web.archive.org/web/20180924185534/https://marineschepen.nl/schepen/zeprov.html#specs|archive-date=24 September 2018|url-status=live}}</ref>

====Littoral combat ship (LCS)====
[[File:Lockheed Martin LCS 17 (48301133431) (cropped).jpg|thumb|{{USS|Indianapolis|LCS-17|6}}, a {{sclass|Freedom|littoral combat ship}} of the United States Navy]]
Some new classes of ships similar to [[corvette]]s are optimized for high-speed deployment and combat with small craft rather than combat between equal opponents; an example is the U.S. [[littoral combat ship]] (LCS). As of 2015, all {{sclass|Oliver Hazard Perry|frigate|2}}s in the United States Navy have been decommissioned, and their role partially being assumed by the new LCS. While the LCS class ships are smaller than the frigate class they will replace, they offer a similar degree of weaponry while requiring less than half the crew complement and offering a top speed of over {{convert|40|kn}}. A major advantage for the LCS ships is that they are designed around specific mission modules allowing them to fulfill a variety of roles. The modular system also allows for most upgrades to be performed ashore and installed later into the ship, keeping the ships available for deployment for the maximum time.

The latest U.S. deactivation plans mean that this is the first time that the U.S. Navy has been without a frigate class of ships since 1943 (technically {{USS|Constitution}} is rated as a frigate and is still in commission, but does not count towards Navy force levels).<ref>{{cite web |last=Larter |first=David |date=2 July 2014 |title=Decommissioning plan pulls all frigates from fleet by end of FY '15 |url=http://www.militarytimes.com/article/20140702/NEWS04/307020082/Decommissioning-plan-pulls-all-frigates-from-fleet-by-end-FY-15 |url-status=live |archive-url=https://web.archive.org/web/20140703031337/http://www.militarytimes.com/article/20140702/NEWS04/307020082/Decommissioning-plan-pulls-all-frigates-from-fleet-by-end-FY-15 |archive-date=3 July 2014 |access-date=25 July 2015 |work=Militarytimes.com}}</ref> The remaining 20 LCSs to be acquired from 2019 and onwards that will be enhanced will be designated as frigates, and existing ships given modifications may also have their classification changed to ''FF'' as well.<ref>[http://news.usni.org/2015/01/15/sna-modified-littoral-combat-ship-class-changed-fast-frigate SNA: Modified Littoral Combat Ships to be Designated Frigates] {{Webarchive|url=https://web.archive.org/web/20170806141654/https://news.usni.org/2015/01/15/sna-modified-littoral-combat-ship-class-changed-fast-frigate|date=6 August 2017}} – News.USNI.org, 15 January 2015</ref> However, the [[United States Navy]] selected a [[FREMM multipurpose frigate]] variant for a new {{sclass|Constellation|frigate|4}} of 20 frigates, to be built by Fincantieri beginning in 2024. <ref>{{Cite web|title=Fincantieri Wins $795M Contract for Navy Frigate Program|url=https://news.usni.org/2020/04/30/fincantieri-wins-795m-contract-for-navy-frigate-program|date=30 April 2020|website=USNI News|language=en-US|access-date=1 May 2020}}</ref>

====Further developments====
[[File:Maritime Security Belt 2023 - Photo op exercise (14).jpg|thumb|[[Project 22350 frigate|Admiral Gorshkov class frigates]] are armed with [[3M22 Zircon|Zircon]] Hypersonic cruise missiles]]
[[File:Auvergne D654 W Kiel 18-06-2023.jpg|thumb|The stealthy [[FREMM multipurpose frigate]] of the French Navy]]
[[File:BADEN-WURTTEMBERG 00257 (cropped).jpg|thumb|Baden-Württemberg, the lead ship of [[Baden-Württemberg-class frigate|her class of frigates]] in the [[Bundesmarine|German Navy]], is currently the largest frigate in the world.]]
[[Stealth technology]] has been introduced in modern frigate design by the French {{sclass|La Fayette|frigate|4}} design.<ref>{{Cite news|url=http://www.militaryfactory.com/ships/frigates.asp|title=Navy Frigate Warships|access-date=2017-07-13|archive-url=https://web.archive.org/web/20170701095136/http://www.militaryfactory.com/ships/frigates.asp|archive-date=1 July 2017|url-status=live}}</ref> Frigate shapes are designed to offer a minimal [[radar cross section]], which also lends them good air penetration; the maneuverability of these frigates has been compared to that of sailing ships. Examples are the Italian and French {{sclass2|Horizon|frigate|4}} with the [[Aster 15]] and [[Aster 30]] missile for anti-missile capabilities, the [[Germany|German]] {{sclass2|F125|frigate|5}} and {{sclass|Sachsen|frigate|2}}<nowiki/>s, the [[Russia]]n {{sclass2|Admiral Gorshkov|frigate|5}} classes with the [[3M22 Zircon|Zircon missile]], the [[India]]n {{sclass|Shivalik|frigate|5}}, {{sclass|Talwar|frigate|5}} and {{sclass|Nilgiri|frigate|5||2019}} classes with the [[Brahmos missile]] system and the [[Malaysia]]n {{sclass|Maharaja Lela|frigate|4}} with the [[Naval Strike Missile]].

The modern [[French Navy]] applies the term first-class frigate and second-class frigate to both destroyers and frigates in service. Pennant numbers remain divided between F-series numbers for those ships internationally recognised as frigates and D-series pennant numbers for those more traditionally recognised as destroyers. This can result in some confusion as certain classes are referred to as frigates in French service while similar ships in other navies are referred to as destroyers. This also results in some recent classes of French ships such as the {{sclass2|Horizon|frigate|4}} being among the largest in the world to carry the rating of frigate. The ''Frégates de Taille Intermédiaire'' (FTI), which means frigates of intermediate size, is a French military program to design and create a planned class of frigates to be used by the French Navy. At the moment, the program consists of five ships, with commissioning [[Future of the French Navy|planned from 2023 onwards]].<ref>{{cite web|url=http://www.navyrecognition.com/index.php?option=com_content&view=article&id=2747|title=Update to French Military Planning Law Means New Capabilities for Lafayette Class Frigates|date=21 May 2015 |publisher=navyrecognition.com|access-date=19 December 2020|archive-date=13 February 2021|archive-url=https://web.archive.org/web/20210213214727/http://www.navyrecognition.com/index.php?option=com_content&view=article&id=2747|url-status=live}}</ref>

In the [[German Navy]], frigates were used to replace aging destroyers; however in size and role the new German frigates exceed the former class of destroyers. The future German {{sclass2|F125|frigate|1}}s are the largest class of frigates worldwide with a displacement of more than 7,200&nbsp;tons. The same was done in the [[Spanish Navy]], which went ahead with the deployment of the first [[Aegis combat system|Aegis]] frigates, the {{sclass|Álvaro de Bazán|frigate|2}}s. The [[Myanmar Navy]] is producing modern frigates with a reduced [[radar cross section]] known as the {{sclass2|Kyan Sittha|frigate|1}}. Before the Kyan Sittha class, the Myanmar Navy also produced an {{sclass|Aung Zeya|frigate|1}}. Although the size of the Myanmar Navy is quite small, it is producing modern guided-missile frigates with the help of Russia, China, and India. However, the fleets of the Myanmar Navy are still expanding with several on-going shipbuilding programmes, including one {{cvt|135|m|ftin}}, 4,000-tonne frigate with the [[Vertical launching system|vertical missile launch systems]].<ref name="auto">{{cite web|url=https://www.newagebd.net/article/126158/myanmar-navys-quick-march|title=Myanmar navy's quick march|author=Mohammad Abdur Razzak|accessdate=4 January 2021|archive-url=https://web.archive.org/web/20210205051848/https://www.newagebd.net/article/126158/myanmar-navys-quick-march|archive-date=5 February 2021|url-status=live|df=dmy-all|date=5 February 2021}}</ref> The four planned [[Tamandaré-class frigate|''Tamandaré''-class frigates]] of the [[Brazilian Navy]] will be responsible for introducing ships with stealth technology in the national navy and the Latin American region, with the first boat expected to be launched in 2024.<ref>{{Cite news|url=https://www.pucara.org/post/brasil-inicia-construcci%C3%B3n-de-fragatas-clase-tamandar%C3%A9|title=Brasil inicia construcción de fragatas clase Tamandaré|website=Pucará Defensa|date=9 September 2022|language=es}}</ref><ref>{{Cite news|url=https://www.defesaaereanaval.com.br/naval/batimento-de-quilha-da-fragata-tamandare-sera-em-marco-de-2023|title=Batimento de quilha da Fragata 'Tamandaré' será em março de 2023|date=11 September 2022|website=Defesa Aérea e Naval|language=pt}}</ref>