View source for SSN (hull classification symbol)

{{Short description|Symbol for nuclear-powered general-purpose attack submarine}}

[[File:US Navy 080621-N-8467N-001 Pre-commissioning Unit New Hampshire (SSN 778) sits moored to the pier at General Dynamics Electric Boat shipyard moments before her christening ceremony commenced.jpg|300px|thumb|right|{{USS|New Hampshire|SSN-778}}, a {{sclass|Virginia|submarine|1}}]]
An '''SSN''' is a [[Nuclear marine propulsion|nuclear-powered]] general-purpose [[attack submarine]]. ''SSN'' is the [[US Navy hull classification symbol]] for such vessels; the ''SS'' (as 'Ship Submersible') denotes a [[submarine]]<ref>In the [[Royal Navy]], "SS" is an abbreviation for ''"Ship Submersible"''{{cite web | url = http://www.royal-navy.mod.uk/server/show/nav.2441 | title = Fleet Submarines (SSN) | work = Royal Navy website | access-date = 2008-04-07 | url-status = dead | archive-url = https://web.archive.org/web/20080404154223/http://www.royal-navy.mod.uk/server/show/nav.2441 | archive-date = 2008-04-04 }}</ref> and the ''N'' denotes [[nuclear power]]. The designation SSN is used for interoperability throughout [[NATO]] under [[Standardization Agreement|STANAG]] 1166,<ref>{{cite web|url=https://www.fas.org/irp/doddir/other/nato2008a.pdf|title=NATO glossary of abbreviations used in NATO documents and publications (AAP-11)|publisher=[[NATO]]|access-date=1 February 2014|url-status=dead|archive-url=https://web.archive.org/web/20140201195708/https://www.fas.org/irp/doddir/other/nato2008a.pdf|archive-date=1 February 2014}}</ref> though navies use other terms.

==History==
The first nuclear-powered attack submarine was the US Navy's {{USS|Nautilus|SSN-571|6}}, operational from 1954. This was followed by the four submarines of the {{sclass|Skate|submarine|4}} entering service in 1957. 
The Royal Navy's first nuclear fleet submarine was {{HMS|Dreadnought|S101|6}} which by using an American reactor entered service in 1963. The first all-British nuclear submarines were the two {{sclass|Valiant|submarine|1}}s.

The USN submarine fleet has been all-nuclear powered for over three decades. The last Barbel-class diesel-electric attack submarine, {{USS|Blueback|SS-581}}, was decommissioned in 1990. The bulk of the USN's SSN fleet has been the [[Los Angeles-class submarine|''Los Angeles''-class attack submarine]]. Designed during the [[Cold War]] the ''Los Angeles''-class boats{{'}} ''raison d'etre'' was to protect USN [[carrier battle group]]s and to hunt [[Soviet Navy]] [[Ballistic missile submarine|SSBNs]] before they could launch a first strike against the United States.

The first ever major combat action involving an SSN was during the 1982 [[Falklands War]]. An Argentinian cruiser, {{ship|ARA|General Belgrano}} was sunk by [[torpedo]]es fired by the Royal Navy fleet submarine {{HMS|Conqueror|S48|6}}. After that incident, the Argentinian Navy was effectively confined to port.

Since the end of the Cold War, SSNs have evolved into multi-mission submarines. Their roles include submarine-launched [[cruise missile]] platforms, intelligence gathering platforms, insertion and exfiltration of [[special forces]] teams in addition to traditional hunter-killer SSN roles.

The advantages of an SSN over a conventionally powered [[Hull classification symbol#Submarine type|SSK]] are much longer endurance (limited more by the crew than the boat, a nuclear submarine can stay submerged for months and does not need refueling in their 25-year lifespans), and higher speed. Unlike most SSKs, SSNs do not have to surface periodically for air, which would compromise their stealth. Some of the newest conventional submarines approach these advantages: [[Stirling engine]] powered vessels can cruise underwater for up to two weeks and, like diesel/electric vessels (and in theory [[liquid oxygen|LOX]] powered vessels), are significantly quieter than nuclear submarines, since they do not need to run the powerful (and noisy) pumps associated with the cooling circuits of pressurized water reactors.

The main disadvantages of an SSN are the technological challenges and expenses of building and maintaining a [[nuclear power]] plant. Nuclear submarines can have political downsides, as some countries refuse to accept nuclear-powered vessels as a matter of policy. Furthermore, [[Nuclear decommissioning|decommissioned]] nuclear submarines require costly dismantling and long term storage of the [[radioactive waste]].

The following navies currently operate SSNs:
* [[People's Liberation Army Navy]] of China
* [[French Navy]]
* [[Indian Navy]]
* [[Russian Navy]]
* [[Royal Navy]] of the United Kingdom
* [[United States Navy]]

==Active and future SSN classes==

;{{flagicon|Australia}} [[Royal Australian Navy]]
* [[Virginia-class submarine]] &ndash; three planned (with an option to purchase a further two vessels)
* [[SSN-AUKUS]] &ndash; up to eight planned

;{{flagicon|Brazil}} [[Brazilian Navy]]
*[[Brazilian submarine Álvaro Alberto]] &ndash; one under construction<ref>{{cite news |title=Brazil take first step in program to join nuclear-powered sub club|url=https://www.reuters.com/article/us-brazil-submarine/brazil-take-first-step-in-program-to-join-nuclear-powered-sub-club-idUSKBN1OD2CV|website=Reuters|date=14 December 2018}}</ref><ref>{{cite news|title=Brazilian Navy - Marinha do Brasil - Modernization|url=https://www.globalsecurity.org/military/world/brazil/navy-mods.htm|accessdate=7 May 2019|publisher=GlobalSecurity.org}}</ref><ref>{{cite news |title=Launch prediction|url=https://www.marinha.mil.br/programas-estrategicos/prosub|language=pt|access-date=25 January 2022|website=Brazilian Navy}}</ref>

;{{flagicon|China}} [[People's Liberation Army Navy]] of the People's Republic of China

*[[Type 091 submarine|''Han''-class]] submarine (Type 091) &ndash; three in service, two retired
*[[Type 093 submarine|Type 093]] submarine &ndash; six in service
*[[Type 095 submarine|Type 095]] submarine &ndash; five planned <ref>{{Cite web|url=http://www.deagel.com/Nuclear-Attack-Submarines/Type-095_a001843001.aspx|title=Type 095|website=www.deagel.com|access-date=2018-07-20}}</ref><ref>{{Cite web|url=http://www.taipeitimes.com/News/editorials/archives/2006/12/06/2003339341|title=Chinese fast developing advanced submarines|website=www.taipeitimes.com|date=6 December 2006|access-date=2018-07-20}}</ref>

;{{flagicon|France}} [[French Navy]]
*{{sclass|Rubis|submarine|1}} &ndash; two in service, four retired
*[[French Barracuda-class submarine|''Barracuda''-class submarine]] &ndash; three in service, total of six planned

;{{flagicon|India}} [[Indian Navy]]
*{{sclass|Akula|submarine|1}} &ndash; one to be delivered by 2028.<ref>{{Cite news |date=2024-10-24 |title=India launches its latest nuclear submarine with 75% indigenous tech: Here's what the new S4 means for regional security |url=https://economictimes.indiatimes.com/news/defence/indias-launches-its-latest-nuclear-submarine-with-75-indigenous-tech-heres-what-the-new-s4-means-for-regional-security/articleshow/114547188.cms?from=mdr |access-date=2025-03-09 |work=The Economic Times |issn=0013-0389}}</ref><ref>{{Cite news |date=2024-11-11 |title=Russia to deliver first of two missile frigates by month-end |url=https://timesofindia.indiatimes.com/india/russia-to-deliver-first-of-two-missile-frigates-by-month-end/articleshow/115152914.cms#amp_tf=From%20%251$s&aoh=17313347570304&csi=0&referrer=https://www.google.com&ampshare=https://timesofindia.indiatimes.com/india/russia-to-deliver-first-of-two-missile-frigates-by-month-end/articleshow/115152914.cms |access-date=2024-11-11 |work=The Times of India |issn=0971-8257}}</ref><ref>{{Cite web|url=https://m-economictimes-com.cdn.ampproject.org/v/s/m.economictimes.com/news/defence/india-russia-to-ink-3-billion-nuclear-submarine-deal-this-week/amp_articleshow/68248638.cms?usqp=mq331AQA&amp_js_v=0.1|title=India Russia Nuclear deal: India, Russia to ink $3 billion nuclear submarine deal this week|website=m-economictimes-com.cdn.ampproject.org|access-date=2019-05-17}}</ref> (Another leased Akula class submarine was returned to Russia in 2021, before the end of its contract.<ref>{{Cite web|url=http://www.ndtv.com/india-news/navys-only-nuclear-attack-submarine-ins-chakra-returns-to-russia-before-lease-expires-2456368|title=Navy's Only Nuclear Attack Submarine Returns To Russia Before Lease Expires|language=en}}</ref><ref>{{Cite web|url=http://indiatoday.intoday.in/story/russia-leases-out-nerpa-nuclear-submarine-to-india/1/166616.html|title=Russia leases out Nerpa nuclear-powered attack submarine to India|website=India Today|language=en|access-date=2018-07-20}}</ref><ref>{{cite web |url=http://www.bharat-rakshak.com/NEWS/newsrf.php?newsid=17638 |title=Archived copy |access-date=2014-04-20 |url-status=dead |archive-url=https://web.archive.org/web/20140421051234/http://www.bharat-rakshak.com/NEWS/newsrf.php?newsid=17638 |archive-date=2014-04-21 }}</ref> ) 
*[[Project 77-class submarine]] &ndash; 2 cleared,<ref>{{Cite web |date=2024-10-09 |title=Centre clears deal to build 2 nuclear submarines, purchase 31 predator drones |url=https://www.indiatoday.in/india/story/nuclear-submarine-deal-centre-31-us-predator-drone-indian-army-navy-2614341-2024-10-09 |access-date=2024-10-10 |website=India Today |language=en}}</ref> 6 planned <ref>{{Cite news|title = Move to fast-track two submarine projects gathers steam - Times of India|url = http://timesofindia.indiatimes.com/India/Move-to-fast-track-two-submarine-projects-gathers-steam/articleshow/38342676.cms|website = The Times of India| date=14 July 2014 |access-date = 2016-02-19}}</ref><ref>{{Cite web|title = Government clears construction of 7 stealth frigates, 6 nuclear-powered attack submarines|url = http://articles.economictimes.indiatimes.com/2015-02-18/news/59268906_1_submarines-frigates-indian-ocean-region|archive-url = https://web.archive.org/web/20150402103923/http://articles.economictimes.indiatimes.com/2015-02-18/news/59268906_1_submarines-frigates-indian-ocean-region|url-status = dead|archive-date = April 2, 2015|website = timesofindia-economictimes|access-date = 2016-02-19}}</ref>
 
;{{flagicon|Russia}} [[Russian Navy]]
*[[Victor-class submarine#Victor III|Victor III-class submarine]] &ndash; two in service, 46 retired 
*[[Sierra-class submarine|Sierra II-class submarine]] &ndash; two in service
*{{sclass|Akula|submarine|1}} &ndash; 10 in service, four retired
*[[Yasen-class submarine|''Yasen''-class submarine]] &ndash; three in service, one on sea trials, total of 12 planned

;{{flagicon|United Kingdom}} [[Royal Navy]] of the United Kingdom
(Known as "fleet submarines" in the Royal Navy.)
[[File:Astute2cropped.jpg|thumb|upright|right|{{HMS|Astute|S119|6}}, an  {{sclass|Astute|submarine|1}}.]]

*{{sclass|Trafalgar|submarine|1}} &ndash; one in service, six retired
*{{sclass|Astute|submarine|1}} &ndash;  five in service, two more under construction
*[[SSN-AUKUS]] &ndash; 12 Planned (first design contract awarded)

;{{flagicon|United States}} [[United States Navy]]

*{{sclass|Los Angeles|submarine|1}} &ndash; 30 in service, 32 retired
*{{sclass|Seawolf|submarine|1}} &ndash; three in service
*{{sclass|Virginia|submarine|1}} &ndash; 19 in service, 66 planned in total
*[[SSN(X)-class submarine]] &ndash; number TBD (under development)

==Retired SSN classes==
;{{flagicon|India}} [[Indian Navy]]
*{{INS|Chakra|1987}} was formerly the {{sclass2|Charlie|submarine}} ''K-43'' leased in 1987 from Russia and returned in 1991. <ref>{{Cite web|url=https://m-economictimes-com.cdn.ampproject.org/v/s/m.economictimes.com/news/defence/india-russia-to-ink-3-billion-nuclear-submarine-deal-this-week/amp_articleshow/68248638.cms?usqp=mq331AQA&amp_js_v=0.1|title=India Russia Nuclear deal: India, Russia to ink $3 billion nuclear submarine deal this week|website=m-economictimes-com.cdn.ampproject.org|access-date=2019-05-17}}</ref><ref>{{Cite web|url=https://thediplomat.com/2019/03/report-india-russia-sign-3-billion-nuclear-attack-submarine-deal/|title=Report: India, Russia Sign $3 Billion Nuclear Attack Submarine Deal|last=Diplomat|first=Franz-Stefan Gady, The|website=The Diplomat|language=en-US|access-date=2019-05-17}}</ref>
*{{INS|Chakra|2011}} was formerly the {{sclass|Akula|submarine}} ''Nerpa'' leased from Russia in 2011 and returned in June 2021.

;{{flagicon|United Kingdom}} [[Royal Navy]] of the United Kingdom
* {{HMS|Dreadnought|S101|6}} - the Royal Navy's first nuclear-powered fleet submarine 1963 - 1980
* {{sclass|Valiant|submarine|1}} - 2 submarines in service 1966 - 1994
* {{sclass|Churchill|submarine|1}}  - 3 submarines in service 1970 - 1992
* {{sclass|Swiftsure|submarine|1}} - 6 submarines 1973-2010

;{{flagicon|Soviet Union}} [[Soviet Navy|Soviet]] / {{flagicon|Russia}} [[Russian Navy]]
* [[November-class submarine]] 1958-1991
* [[Soviet submarine K-278 Komsomolets|K-278 ''Komsomolets'']]  - only member of the "Mike" class, 1984 - 1989 (sank after fire)
* [[Alfa-class submarine]]

;{{flagicon|United States}} [[United States Navy]]
* {{USS|Nautilus|SSN-571}} (unique)
* {{USS|Seawolf|SSN-575}} (unique)
* {{sclass|Skate|submarine|1}} - 4 submarines in service 1957 - 1989
* {{sclass|Skipjack|submarine|1}} - 6 submarines in service 1959 - 1990 (One lost, 1968)
* [[USS Triton (SSRN-586)|USS ''Triton'' (SSN-586)]] (unique)
* [[USS Halibut (SSGN-587)|USS ''Halibut'' (SSN-587)]] (unique)
* {{sclass|Permit|submarine|1}} - 14 submarines in service 1961 - 1996 (One lost, 1963)
* {{USS|Tullibee|SSN-597}} (unique)
* {{sclass|Sturgeon|submarine|1}} - 37 submarines in service 1967 - 2004
* {{USS|Narwhal|SSN-671}} (unique)
* {{USS|Glenard P. Lipscomb|SSN-685}} (unique)

==See also==
* [[Nuclear submarine]]
* [[Ballistic missile submarine]] (SSB/SSBN)
* [[Cruise missile submarine]] (SSG/SSGN)
* [[List of submarine classes]]
* [[List of submarine classes of the Royal Navy]]
* [[List of Soviet and Russian submarine classes]]
* [[List of submarine classes of the United States Navy]]

==References==
{{Reflist}}

{{Current SSN}}

{{DEFAULTSORT:Ssn (Hull Classification Symbol)}}
[[Category:Attack submarines]]