View source for Engineering:Stealth ship

{{Short description|Ship which uses stealth technology to reduce risk of detection}}
[[File:Royal Navy Type 45 destroyer HMS Daring MOD 45154175.jpg|thumb|The [[Engineering:Type 45 destroyer|Type 45]] Royal Navy destroyer. Examples of stealthy ships.]]
A '''stealth ship''' is a ship that employs [[Engineering:Stealth technology|stealth technology]] construction techniques in an effort to make it harder to detect by one or more of [[Engineering:Radar|radar]], visual, sonar, and infrared methods.

These techniques borrow from [[Engineering:Stealth aircraft|stealth aircraft]] technology, although some aspects such as wake and acoustic signature reduction ([[Physics:Acoustic quieting|acoustic quieting]]) are unique to stealth ships' design. Although [[Physics:Radar cross-section|radar cross-section]] (RCS) reduction is a fairly new concept, many other forms of masking a ship have existed for centuries or even millennia.

==Shaping==
{{Main|Engineering:Naval architecture}}
[[File:Cheminee tribord du forbin.JPG|thumb|upright|Detail of ''Forbin'', a modern frigate of the French navy. The faceted appearance reduces radar cross-section for stealth.]]thumb|US Navy [[Sea Shadow (IX-529) uses both a tumblehome hull and SWATH to reduce its radar return. But fully stealth ship designs are rare.]]

In designing a ship with a reduced radar signature, the main concerns are radar beams originating near or slightly above the horizon (as seen from the ship) coming from distant patrol aircraft, other ships, or sea-skimming [[Engineering:Anti-ship missile|anti-ship missile]]s with [[Engineering:Active radar homing|active radar seekers]]. Therefore, the shape of the ship avoids vertical surfaces, which are effective at reflecting such beams directly back to the emitter. Retro-reflective right angles are eliminated to avoid the [[Physics:Chatoyancy|cat's eye effect]]. A stealthy ship shape can be achieved by constructing the hull and superstructure with a series of slightly protruding and retruding surfaces.{{citation needed|date=February 2015}} Furthermore, round shapes on the ship are eliminated or covered up, examples being smokestacks and gun turrets. Also, cavities that present a horizontal face are to be eliminated since they are very visible to radar. To bypass these limitations, many ships use features such as panels that cover reflective surfaces or use alternate designs of hardware. Additionally, efforts are made to minimize gaps on the ship. Hull shapes include [[Engineering:Tumblehome|tumblehome]] hull designs, which slope inward from the waterline, and [[Engineering:Small-waterplane-area twin hull|small-waterplane-area twin hull]]s (SWATH), which allow for better stability when using a tumblehome hull. These RCS design principles were developed by several navies independently in the 1980s using work done on [[Engineering:Stealth aircraft|aircraft RCS]] reduction as the starting point.

''Sea Shadow'', which utilizes both [[Engineering:Tumblehome|tumblehome]] and SWATH features, was an early US exploration of stealth ship technology. The currently-serving ''Zumwalt''-class destroyer is a modern example of a stealth ship from the US Navy. Despite being 40% larger than an ''Arleigh Burke''-class destroyer, its radar signature is more akin to a fishing boat, according to a spokesman for Naval Sea Systems Command;<ref name="CNN2014">{{cite news |url= http://www.cnn.com/2014/06/14/tech/zumwalt-operations-center |title= Navy's stealth destroyer designed for the video gamer generation |first1=Thom |last1=Patterson |first2=Brad |last2=Lendon |publisher= CNN |date= 14 June 2014 |access-date=29 October 2014}}</ref> sound levels are comparable to the {{sclass|Los Angeles|submarine}}. The [[Engineering:Tumblehome|tumblehome]] hull and composite material deckhouse reduce radar return. Water sleeting along the sides, along with passive cool air induction in the [[Engineering:Mack (naval architecture)|mack]], reduces [[Physics:Infrared signature|infrared signature]].<ref name="global_dd-x">{{cite web| url=http://www.globalsecurity.org/military/systems/ship/dd-x.htm |title=DDG-1000 Zumwalt / DD(X) Multi-Mission Surface Combatant |date=1 September 2008 |publisher=GlobalSecurity.org}}</ref> Overall, the destroyer's angular build makes it "50 times harder to spot on radar than an ordinary destroyer", according to Chris Johnson, a spokesman for Naval Sea Systems Command.<ref name="CNN2014"/>

The Swedish Navy's [[Engineering:Visby-class corvette|''Visby''-class corvette]] is designed to elude visual detection, radar detection, acoustic detection, and [[Physics:Infrared signature|infrared detection]]. The hull material is a sandwich construction comprising a PVC core with carbon fiber and vinyl laminate.<ref>{{Cite web|title = Visby Class, Sweden|url = http://www.naval-technology.com/projects/visby/|website = www.naval-technology.com|access-date = 2015-07-31}}</ref> Avoidance of [[Right angle|right angle]]s in the design results in a smaller radar signature, reducing the ship's detection range.

The Royal Navy's [[Engineering:Type 45 destroyer|Type 45 destroyer]] has similarities to the ''Visby'' class, but is much more conventional, employing traditional steel instead of carbon fiber. Like ''Visby'', its design reduces the use of right angles.

The ROC Navy's ''Tuo Chiang''-class corvette is a class of fast stealth multi-mission corvettes currently in service with the Republic of China (Taiwan) Navy. The ships are designed to have a low radar cross-section and evade radar detection making it difficult to detect the ship when operating closer to the coastline<ref>{{cite web|url=http://www.foxnews.com/tech/2014/12/12/taiwanese-navy-showcases-new-killer-stealth-corvette.html|title=Taiwanese Navy showcases new 'killer' stealth warship|website=Fox News|date=12 December 2014}}</ref><ref>{{cite web|url=http://phys.org/news/2011-07-taiwan-stealth-technology-breakthrough.html|title=Taiwan in stealth technology breakthrough: report}}</ref><ref>{{cite web|url=http://www.popsci.com/article/technology/taiwan-navy-launches-new-stealth-boat|title=Taiwan Navy Launches New Stealth Boat|date=18 March 2019}}</ref><ref>{{cite web|url=http://www.businessinsider.com/taiwan-navy-stealth-missile-warship-corvette-2014-12|title=The Taiwan Navy Just Unveiled A Stealth Missile Warship Dubbed The 'Carrier-Killer'|website=Business Insider}}</ref><ref>{{cite web|url=https://news.usni.org/2014/12/24/taiwan-navy-takes-delivery-first-stealth-carrier-killer-corvette|title=Taiwan Navy Takes Delivery of First Stealth 'Carrier Killer' Corvette|date=24 December 2014}}</ref>

==Signature reduction==
[[Engineering:Stealth technology|Stealth technology]] represents more than just a low [[Physics:Radar cross-section|RCS]]; noise reduction plays a role in naval stealth because sound is conducted better in water than air. Some of the techniques used include muffled exhaust systems, modified propeller shapes, and [[Engineering:Pump-jet|pump-jet]]s. The shape of the hull can also have a great effect on the reduction of the noise from a ship. Another major element is signal emission control. Modern warships emit much electromagnetic radiation in the form of radar, radio, and bleed-off from the ship's electrical systems. These all can be used to track a ship, and thus modern stealth ships often have a mode that switches off many of the electronic emissions (EMCON), the downside being the ship has to rely on passive sensors and is unable to easily send messages further than the line of sight.

Also of importance are thermal emissions. A [[Physics:Infrared signature|heat signature]] can make a ship stand out in the ocean, making it easier to spot. Because it is possible to see infrared emissions through features that would normally hide a ship such as fog, or a smoke screen, many detection platforms like patrol aircraft, UAVs, and satellites often have the ability to see multiple bands in the infrared spectrum. This necessitates the control of thermal emissions. The most common method is to mix any hot gasses emitted by the main source of heat—the engines' exhaust—with cold air to dilute the signature and make it harder to pick out the ship from the background warmth. Another method vents the exhaust into the water, although this increases the ship's acoustic signature. For the hull, cool water can be actively distributed across the hull of the ship. Another less crucial but still relevant part of a stealth ship is visual camouflage. This area is probably the oldest form of stealth, with records going back almost as far as the writing of ancient mariners using visual tricks to make their ships harder to spot. Although still relevant, this area has taken on lesser importance with the advent of long-range radar.

==Materials==
Just like choices in shaping, the choice of materials affects the [[Physics:Radar cross-section|RCS]] of a ship. Composites like [[Chemistry:Fiberglass|fiberglass]] and carbon fiber are effective blockers of radar and give smaller vessels an advantage in further [[Physics:Radar cross-section|RCS]] reductions. However, composites are fragile and often unsuited to larger ships or ships that expect to take fire, although new laminates can partially negate some of the weaknesses. This restricts larger ships to metals like steel and aluminum alloys. To compensate, a ship may include a coating of a radar-absorbing material, although this can be expensive and may not stand up to the corrosive effects of salt water.

==Examples==

===Fully stealth ships===
(Year of commission)
[[Image:FS Surcouf.jpg|thumb|French frigate ''Surcouf'' of the ''La Fayette'' class ]]
[[File:French Navy Offshore Patrol Ship P725 Adroit.jpg|thumb|[[Engineering:Gowind-class design|Gowind-class]] will be used in various countries.]]
[[File:USS Zumwalt is on the final leg of its three-month journey to its new homeport in San Diego. (31620613005).jpg|thumb|One of the largest class fully stealth ship is [[Engineering:Zumwalt-class destroyer|Zumwalt-class]]]]
* {{annotated link|Engineering:Sea Shadow (IX-529)|''Sea Shadow'' (IX-529)}} (1985, experimental platform)
* {{annotated link|Engineering:La Fayette-class frigate|''La Fayette''-class frigate}} (1996)
* {{annotated link|Engineering:Skjold-class corvette|''Skjold''-class corvette}} (1999)
* {{annotated link|Engineering:Type 22 missile boat}} (2004)
* {{annotated link|Engineering:Formidable-class frigate|''Formidable''-class frigate}} (2007)
* {{annotated link|Engineering:Visby-class corvette|''Visby''-class corvette}} (2009)
* {{annotated link|Engineering:Zumwalt-class destroyer|''Zumwalt''-class destroyer}} (2016)
* {{annotated link|Engineering:Gowind-class design}} (2017)
* {{annotated link|Engineering:Type 055 destroyer}} (2020)
{{clear}}

===Ships with moderate radar cross-section reduction===
[[File:VPNS 015 Trần Hưng Đạo & F48 INS Satpura in AIME 2023.jpg|thumb|Gepard-class frigate and Shivalik-class frigate]]
[[File:F805 Evertsen.jpg|thumb|Dutch frigate ''Evertsen'' of the ''De Zeven Provinciën'' class ]]
[[File:French destroyer Forbin (D620) underway in the Arabian Sea on 31 May 2009 (090531-N-9988F-406).jpg|thumb|[[Engineering:Horizon-class frigate|Horizon-class frigate]] of the French Navy and Italian Navy ]]
* {{Annotated link |Durango-class patrol vessel|''Durango''-class patrol vessel}}
* {{Annotated link |Sierra-class corvette|''Sierra''-class corvette}}
* {{Annotated link |Admiral Gorshkov-class frigate|''Admiral Gorshkov''-class frigate}}
* {{Annotated link |Type 052C destroyer}}
* {{Annotated link |Type 052D destroyer}}
* {{Annotated link |Type 45 destroyer}}
* {{Annotated link |Freedom-class littoral combat ship|''Freedom''-class littoral combat ship}}
* {{Annotated link |De Zeven Provinciën-class frigate|''De Zeven Provinciën''-class frigate}}
* {{Annotated link |Horizon-class frigate|''Horizon''-class frigate}}
* {{Annotated link |Baden-Württemberg-class frigate|''Baden-Württemberg''-class frigate }}
* {{Annotated link |Sachsen-class frigate|''Sachsen''-class frigate}}
* {{Annotated link |Talwar-class frigate|''Talwar''-class frigate}}
* {{Annotated link |Type 054A frigate}}
* {{Annotated link |Type 056 corvette}}
* {{Annotated link |Gepard-class frigate|''Gepard''-class frigate}}
* {{Annotated link |Holland-class offshore patrol vessel|''Holland''-class offshore patrol vessel}}
* {{Annotated link |Kamorta-class corvette|''Kamorta''-class corvette}}
* {{Annotated link |Buyan-class corvette|''Buyan''-class corvette}}
* {{Annotated link |Legend-class cutter|''Legend''-class cutter}}
* {{Annotated link |Steregushchiy-class corvette|''Steregushchiy''-class corvette}}
* {{Annotated link |Gremyashchiy-class corvette|''Gremyashchiy''-class corvette}}
* {{Annotated link |FREMM multipurpose frigate}}
* {{Annotated link |Ambassador MK III missile boat}}
* {{Annotated link |Fridtjof Nansen-class frigate|''Fridtjof Nansen''-class frigate}}
* {{Annotated link |Iver Huitfeldt-class frigate|''Iver Huitfeldt''-class frigate}}
{{clear}}

===Reduced radar cross-section ships===
[[File:Myanmar UMS King Sin Phyu Shin (F14) during Milan 2018 exercise.jpg|thumb|Kyan Sittha-class frigate, UMS ''Sinbyushin'' of Myanmar Navy ]]
[[File:Buque Castilla (L52).jpg|thumb|''Enforcer'' design`s ships are used in various countries.]]
[[File:Broadside view of USS Gerald R. Ford (CVN-78) underway on 8 April 2017.JPG|thumb|One of the largest class stealth ship is Gerald R. Ford-class]]
* {{Annotated link |Kyan Sittha-class frigate|''Kyan Sittha''-class frigate}}
* {{Annotated link |Anawrahta-class corvette|''Anawrahta''-class corvette}}
* {{Annotated link |Yan Nyein Aung-class submarine chaser|''Yan Nyein Aung''-class submarine chaser}}
* {{Annotated link |Gerald R. Ford-class aircraft carrier|''Gerald R. Ford''-class aircraft carrier}}
* {{Annotated link |Queen Elizabeth-class aircraft carrier|''Queen Elizabeth''-class aircraft carrier}}
* {{Annotated link |HNLMS Rotterdam (L800) |HNLMS ''Rotterdam'' (L800) amphibious transport dock}}
* {{Annotated link |San Antonio-class amphibious transport dock|''San Antonio''-class amphibious transport dock}}
* {{Annotated link |Type 071 amphibious transport dock}}
* {{Annotated link |Type 23 frigate}}
* {{Annotated link |Arleigh Burke-class destroyer|''Arleigh Burke''-class destroyer}}
* {{Annotated link |Mogami-class frigate|''Mogami''-class frigate}}
* {{Annotated link |Maya-class destroyer|''Maya''-class destroyer}}
* {{Annotated link |Atago-class destroyer|''Atago''-class destroyer}}
* {{Annotated link |Kongō-class destroyer|''Kongō''-class destroyer}}
* {{Annotated link |Sejong the Great-class destroyer|''Sejong the Great''-class destroyer}} (KDX-III)
* {{Annotated link |Chungmugong Yi Sun-sin-class destroyer|''Chungmugong Yi Sun-sin''-class destroyer}} (KDX-II)
* {{Annotated link |Visakhapatnam-class destroyer|''Visakhapatnam''-class destroyer}}
* {{Annotated link |Kolkata-class destroyer|''Kolkata''-class destroyer}}
* {{Annotated link |Shivalik-class frigate|''Shivalik''-class frigate}}
* {{Annotated link |Martadinata-class frigate|''Martadinata''-class frigate}}
* {{Annotated link |Yoon Youngha-class patrol vessel|''Yoon Youngha''-class patrol vessel }}
* {{Annotated link |Neustrashimy-class frigate|''Neustrashimy''-class frigate}}
* {{Annotated link |Kedah-class offshore patrol vessel|''Kedah''-class offshore patrol vessel}}
* {{Annotated link |Álvaro de Bazán-class frigate|'' Álvaro de Bazán''-class frigate}}
* {{Annotated link |Braunschweig-class corvette|''Braunschweig''-class corvette}}
* {{Annotated link |Jose Rizal-class frigate|''Jose Rizal''-class frigate}}
* {{Annotated link |Sigma-class design|''Sigma''-class corvette}}
* {{Annotated link |Nongo class|''Nongo'' class}}
* {{Annotated link |Admiral Grigorovich-class frigate|''Admiral Grigorovich''-class frigate}}
* {{Annotated link |OPV-80-class offshore patrol vessel}}
* {{Annotated link |Valour-class frigate|''Valour''-class frigate}}
* {{Annotated link |Oaxaca-class patrol vessel|''Oaxaca''-class patrol vessel}}
{{clear}}

===Planned ships===
* F126 frigate
* {{annotated link|Engineering:Type 212CD submarine}}

==Gallery==

<gallery mode="packed">

</gallery>

==References==
{{Reflist|30em}}

==External links==
* [https://web.archive.org/web/20100705034051/http://www.memagazine.org/backissues/membersonly/jan01/features/stealth/stealth.html "Stealth on the Water"] "Mechanical Engineering"
*[http://www.foxnews.com/tech/2014/12/12/taiwanese-navy-showcases-new-killer-stealth-corvette.html Taiwanese navy showcases new killer stealth corvette]
*[http://www.defensenews.com/story/defense/naval/ships/2014/12/23/taiwan-launches-its-largest-ever-missile-ship/20826049/ Taiwan launches its largest ever stealth missile ship]
*[http://phys.org/news/2011-07-taiwan-stealth-technology-breakthrough.html Taiwan stealth technology breakthrough]
*[http://www.businessinsider.com/taiwan-navy-stealth-missile-warship-corvette-2014-12 Taiwan navy stealth missile warship corvette]
*[http://www.popsci.com/article/technology/taiwan-navy-launches-new-stealth-boat Taiwan navy launches new stealth boat]
*[http://www.scmp.com/news/china/article/1668158/taiwan-navy-testing-stealth-frigates Taiwan navy testing stealth frigates]
*[https://web.archive.org/web/20070808165330/http://peoships.crane.navy.mil/DDG1000/default.htm DDG 1000 information; formerly DD(X)]
*[https://web.archive.org/web/20060826050140/http://www.bharat-rakshak.com/NAVY/Project17.html Shivalik class frigate]
*[http://news.bbc.co.uk/1/hi/technology/3724219.stm Stealth ships steam ahead] article by Chris Summers on BBC news, 10 June 2004


[[Category:Stealth ships| ]]
[[Category:Radar]]
[[Category:Ship types]]

{{Sourceattribution|Stealth ship}}