View source for DSV Alvin

{{Short description|Crewed deep-ocean research submersible}}
{{Redirect|ALVIN||Alvin (disambiguation){{!}}Alvin}}
{{Use American English|date=January 2024}}
{{Use dmy dates|date=August 2021}}
{|{{Infobox ship begin
| display title = DSV ''Alvin''
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{{Infobox ship image
| Ship image = [[File:ALVIN submersible.jpg|300px|''Alvin'' in 1978, a year after first exploring hydrothermal vents. The rack hanging at the bow holds sample containers.]]
| Ship caption = ''Alvin'' in 1978, a year after first exploring [[hydrothermal vent]]s. The rack hanging at the bow holds sample containers.
}}
{{Infobox ship career
 | Hide header              = 
 | Ship country             = United States
 | Ship flag                = {{USN flag|2012}}
 | Ship name                = ''Alvin''
 | Ship namesake            = [[Allyn Vine]]
 | Ship owner               = 
 | Ship operator            = [[Woods Hole Oceanographic Institution]]
 | Ship registry            = 
 | Ship route               = 
 | Ship ordered             = 
 | Ship awarded             = 
 | Ship builder             = [[General Mills]]' Electronics Group<ref name="WHOI-Hist">{{cite web |url= https://www.whoi.edu/page.do?pid=10737 |title=History of Alvin |publisher=Woods Hole Oceanographic Institution |date= 1 December 2005|access-date=11 November 2017}}</ref>
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 | Ship christened          = 
 | Ship completed           = 
 | Ship acquired            = May 26, 1964
 | Ship in service          = June 5, 1964
 | Ship out of service      = 
 | Ship renamed             = 
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 | Ship refit               = 
 | Ship struck              = 
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 | Ship fate                = 
 | Ship status              = {{Ship in active service | 2024 | url=http://www.whoi.edu/page.do?pid=10736 }}
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}}
{{Infobox ship characteristics
 | Hide header              = 
 | Header caption           = <ref name="WHOI-Specs">{{cite web |url= http://www.whoi.edu/page.do?pid=9915 |title=Alvin Specifications |publisher=Woods Hole Oceanographic Institution |year=2012 |access-date=5 August 2012 |archive-url=https://web.archive.org/web/20120509221913/http://www.whoi.edu/page.do?pid=9915 |archive-date=9 May 2012}}</ref>
 | Ship type                = [[Deep-submergence vehicle]]
 | Ship tonnage             = 
 | Ship displacement        = {{convert|17|t|LT|0|lk=on|abbr=on}}
 | Ship length              = {{convert|7.1|m|ftin|abbr=on}}
 | Ship beam                = {{convert|2.6|m|ftin|abbr=on}}
 | Ship height              = {{convert|3.7|m|ftin|abbr=on}}
 | Ship draft               = {{convert|2.3|m|ftin|abbr=on}}
 | Ship depth               = 
 | Ship power               = 
 | Ship propulsion          = 
 | Ship speed               = {{convert|2|kn|lk=in}}
 | Ship range               = {{convert|5|km|abbr=on}}
 | Ship endurance           = 72 hours with 3 crew
 | Ship test depth          = {{convert|6500|m|abbr=on}}
 | Ship boats               = 
 | Ship capacity            = {{convert|680|kg|abbr=on}} payload
 | Ship crew                = 3 (1 pilot, 2 scientific observers)
 | Ship time to activate    = 
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|}
'''''Alvin''''' ('''DSV-2''') is a crewed deep-ocean research [[submersible]] owned by the [[United States Navy]] and operated by the [[Woods Hole Oceanographic Institution]] (WHOI) of [[Woods Hole, Massachusetts]]. The original vehicle was built by [[General Mills]]' Electronics Group<ref name="WHOI-Hist">{{cite web |url= https://www.whoi.edu/page.do?pid=10737 |title=History of Alvin |publisher=Woods Hole Oceanographic Institution |date= 1 December 2005|access-date=11 November 2017}}</ref> in [[Minneapolis, Minnesota]]. Named to honor the prime mover and creative inspiration for the vehicle, [[Allyn Vine]], ''Alvin'' was commissioned on June 5, 1964.

The submersible is launched from the deep submergence support vessel {{Ship|RV|Atlantis|AGOR-25}}, which is also owned by the U.S. Navy and operated by WHOI. The submersible has made more than 5,200 dives, carrying two scientists and a pilot, observing the lifeforms that must cope with super-pressures and move about in total darkness, as well as exploring the [[Wreck of the RMS Titanic|wreck of ''Titanic'']]. Research conducted by ''Alvin'' has been featured in nearly 2,000 scientific papers.

==Design==
[[File:Alvin (DSV-2) drawing3.jpg|thumb|left|Emergency separation]]
[[File:Alvin (DSV-2) drawing2.jpg|thumb|upright=1.2|General layout]]
''Alvin'' was designed as a replacement for [[bathyscaphe]]s and other less maneuverable [[oceanography|oceanographic]] vehicles. Its more nimble design was made possible in part by the development of [[syntactic foam]], which is buoyant and yet strong enough to serve as a structural material at great depths.

The vessel weighs 17 tons. It allows for two scientists and one pilot to dive for up to nine hours at {{convert|6500|m}}. The submersible features two robotic arms and can be fitted with mission-specific sampling and experimental gear. The [[plug door|plug hatch]] of the vessel is {{convert|0.48|m|abbr=on}} in diameter and somewhat thicker than the {{convert|2|in|adj=on}} thick titanium sphere pressure hull;<ref name="WHOI-Specs" /> it is held in place by the pressure of the water above it.

In an emergency, if previous versions of ''Alvin'' were stuck underwater with occupants inside, an upper part of the submersible including the titanium sphere could be released using controls inside the hull. This would then rise to the surface uncontrolled.<ref>[https://web.archive.org/web/20121102063819/http://www.whoi.edu/page.do?pid=10715 Safety]</ref> The current version of the vehicle uses releasable weights and emergency releases on jettisonable equipment. 

[[Harold E. Froehlich]] was one of the principal designers of ''Alvin''.<ref>{{Cite news|url= https://www.nytimes.com/2007/05/26/us/26froehlich.html |title= Harold Froehlich, 84, Dies; Designed Deep-Sea Minisub |date= 26 May 2007 |last= Pearce |first= Jeremy |work= The New York Times |access-date= 17 March 2017}}</ref>

== History ==

=== Early career ===
''Alvin'', first of its [[ship class]] of [[deep submergence vehicle]] (DSV), was built to dive to {{convert|2440|m}}. Each of the ''Alvin-class'' DSVs have different depth capabilities. However, ''Alvin'' is the only one seconded to the [[National Oceanic and Atmospheric Administration]] (NOAA), with the others staying with the [[United States Navy]].

''Alvin''{{-'}}s first deep sea tests took place off [[Andros Island]], the Bahamas, where it made a successful 12-hour, uncrewed tethered {{convert|7500|ft|m|adj=on}} test dive. On July 20, 1965 ''Alvin'' made its first {{convert|6000|ft|m|adj=on}} crewed dive for the Navy to obtain certification.<ref name="WHOI-Hist"/> On March 17, 1966, ''Alvin'' was used to locate a submerged 1.45-megaton [[hydrogen bomb]] lost in a [[United States Air Force]] [[1966 Palomares B-52 crash|midair accident]] over [[Palomares, Almería|Palomares]], Spain. The bomb, found resting on a steep slope nearly {{convert|2500|ft|abbr=on}} deep, was located by ''Alvin'' but the submersible had difficulty raising it up, initially causing it to fall deeper to {{convert|2800|ft|abbr=on}}. The bomb was eventually raised intact on April 7 by a [[CURV|Navy CURV-I]] and the experience gained by the ''Alvin'' crew's 34 dives with over 220 hours logged led to new improvements to the vehicle's navigations systems.<ref>{{cite web|url=https://www.whoi.edu/oceanus/feature/little-alvin-and-the-lost-h-bomb/|title=The story of "Little Alvin" and the lost H-bomb|website=whoi.edu|access-date=14 April 2024}}</ref>
On July 6, 1967, the ''Alvin'' was attacked by a [[swordfish]] during dive 202. The swordfish became trapped in the ''Alvin''{{-'}}s skin. The attack took place at {{convert|2000|ft|m}} below the surface. The fish was recovered at the surface and cooked for dinner.<ref name="WHOI-Hist"/> During Dive 209, on September 24, 1968 ''Alvin'' found an [[F6F Hellcat]], #42782, 125 miles southeast of [[Nantucket]].<ref>{{cite web|url=http://forum.12oclockhigh.net/showthread.php?t=41818|title=F6F 42782 - Luftwaffe and Allied Air Forces Discussion Forum|website=forum.12oclockhigh.net|access-date=4 May 2019}}</ref> The aircraft had ditched September 30, 1944 during carrier qualifications, with the pilot surviving.<ref name="WHOI-Hist" />

=== Sinking  ===
[[File:Alvin (DSV-2) sunk 1968.jpg|thumb|right|The sunken ''Alvin'' on the ocean bottom in June 1969, photographed by {{USNS|Mizar|T-AGOR-11}}.]] 
''Alvin'', aboard the Navy tender ship ''Lulu'', was lost as it was being transported on October 26, 1968. ''Lulu'', a vessel created from a pair of decommissioned U.S. Navy [[Pontoon (boat)|pontoon boat]]s with a support structure added on, was lowering ''Alvin'' over the side when two steel cables snapped. There were three crew members aboard ''Alvin'' at the time, and the hatch was open. Situated between the pontoons with no deck underneath, ''Alvin'' entered the water and rapidly began to sink. The three crew members managed to escape, but ''Alvin'' flooded and sank in {{convert|1500|m|abbr=on}} of water in the [[Atlantic Ocean]] at approximately {{coord|39|53|30|N|069|15|30|W|name="DSV ''Alvin''"}}, about {{convert|88|nmi|mi km|lk=in}} south of [[Nantucket Island]].<ref name="Salvops69">[http://www.supsalv.org/SalvReports/SALVOPS%2069.pdf ''SALVOPS 69'', Washington, D.C.:Department of the Navy Naval Ship Systems Command, 1969, pp. 1–18.] {{webarchive|url=https://web.archive.org/web/20160424091713/http://www.supsalv.org/SalvReports/SALVOPS%2069.pdf |date=24 April 2016 }}</ref>

Severe weather prevented the recovery of ''Alvin'' throughout late 1968, but it was photographed at the bottom of the Atlantic Ocean in June 1969 by a sled towed by [[USNS Mizar (T-AGOR-11)|USS ''Mizar'']]. ''Alvin'' was found to be upright and appeared intact except for damage to the stern. It was decided to attempt recovery; although no object of ''Alvin''{{'}}s size had ever been recovered from a depth of {{convert|5000|ft}}, recovery was "deemed to be within the state of the art". In August 1969, the ''[[Aluminaut]]'', a DSV built by [[Reynolds Metals Company]], descended to ''Alvin'' but had trouble attaching the required lines, and side effects from [[Hurricane Camille]] were producing worsening weather, causing the team to return to Woods Hole to regroup. The second attempt started on August 27, and ''Aluminaut'' was able to secure a line and safety slings to ''Alvin'' and wrap a nylon net around its hull, allowing it to be hauled up by ''Mizar''. ''Alvin'' was towed, submerged at {{convert|40|ft|m}}, at a speed of {{convert|2|kn|km/h}}, back to Woods Hole.<ref name ="Salvops69" />

=== Post-sinking refit ===
[[File:Alvin (DSV-2) gets refitted with new personal sphere.jpg|thumb|''Alvin'' during refit of the personnel sphere, 1974.]]
In 1973, ''Alvin''{{'}}s pressure hull was replaced by a newer titanium pressure hull. The new hull extended the submersible's depth rating.<ref name="Strickrott 2017" />{{rp|p36}}{{clarify|what was the new depth rating?|date=January 2023}}

===Mid-Atlantic Ridge===
{{main article|Mid-Atlantic Ridge}}With a new, stronger pressure hull ''Alvin'' could now reach the floor of the rift valley of this seafloor spreading center. In the summer of 1974 American and French scientists joined in [[Project FAMOUS]] to explore the creation of new sea floor at this spreading center.<ref>{{Cite journal |last1=Heirtzler |first1=J. R. |last2=Van Andel |first2=Tjeerd H.|date=1977-04-01|title=Project FAMOUS: Its origin, programs, and setting|url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/88/4/481/202106/project-famous-its-origin-programs-and-setting|journal=GSA Bulletin|language=en|volume=88|issue=4|pages=481–487|doi=10.1130/0016-7606(1977)88<481:pfiopa>2.0.co;2|bibcode=1977GSAB...88..481H |issn=0016-7606|url-access=subscription}}</ref><ref>{{Cite journal|last1=Heirtzler|first1=James R.|last2=Le Pichon|first2=Xavier|date=1974-06-01|title=FAMOUS: A Plate Tectonics Study of the Genesis of the Lithosphere|url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/2/6/273/205537/famous-a-plate-tectonics-study-of-the-genesis-of|journal=Geology|language=en|volume=2|issue=6|pages=273–274|doi=10.1130/0091-7613(1974)2<273:faptso>2.0.co;2|bibcode=1974Geo.....2..273H |issn=0091-7613|url-access=subscription}}</ref> The French provided submersibles  ''[[Archimède]]''  and ''CYANA''. A total of forty-four dives were completed that succeeded in defining the crustal accretion zone<ref>{{Cite journal|last1=Luyendyk|first1=Ken C.|last2=Macdonald|first2=Ken C. Bruce P.|date=1976-06-01|title=Spreading center terms and concepts|url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/4/6/369/191576/spreading-center-terms-and-concepts|journal=Geology|language=en|volume=4|issue=6|pages=369–370|doi=10.1130/0091-7613(1976)4<369:sctac>2.0.co;2|bibcode=1976Geo.....4..369L |issn=0091-7613|url-access=subscription}}</ref> in the floor of the rift valley.<ref>{{Cite journal|last1=Moore|first1=James G.|last2=Fleming|first2=Henry S.|last3=Phillips|first3=Joseph D.|date=1974-09-01|title=Preliminary Model for Extrusion and Rifting at the Axis of the Mid-Atlantic Ridge, 36°48′ North|url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/2/9/437/205563/preliminary-model-for-extrusion-and-rifting-at-the|journal=Geology|language=en|volume=2|issue=9|pages=437–440|doi=10.1130/0091-7613(1974)2<437:pmfear>2.0.co;2|issn=0091-7613|url-access=subscription}}</ref>

===Hydrothermal vents===
{{main article|Hydrothermal vent}}
Marine geologists using ''Alvin'' in the [[Pacific Ocean]] discovered deep-sea [[hydrothermal vent]]s and associated biologic communities during two expeditions to ocean [[spreading center]]s. In 1977 scientists in ''Alvin'' discovered low temperature (~20&nbsp;°C) vents on the [[Galápagos Islands|Galapagos]] spreading center east of those same islands.<ref name=":0">{{Cite journal|last1=Corliss|first1=John B.|last2=Dymond|first2=Jack|last3=Gordon|first3=Louis I.|last4=Edmond|first4=John M.|last5=von Herzen|first5=Richard P.|last6=Ballard|first6=Robert D.|last7=Green|first7=Kenneth|last8=Williams|first8=David|last9=Bainbridge|first9=Arnold|date=1979-03-16|title=Submarine Thermal Springs on the Galápagos Rift|journal=Science|language=en|volume=203|issue=4385|pages=1073–1083|doi=10.1126/science.203.4385.1073|issn=0036-8075|pmid=17776033|bibcode=1979Sci...203.1073C |s2cid=39869961 }}</ref> During the [[RISE project (oceanography)|RISE]] expedition in 1979 scientists using ''Alvin'' discovered high temperature vents (380&nbsp;°C) popularly known as ‘[[Hydrothermal vent#Black smokers|black smokers]]’ on the crest of the [[East Pacific Rise]] at 21° N.<ref>{{Cite journal|last1=Spiess|first1=F. N.|last2=Macdonald|first2=K. C.|last3=Atwater|first3=T.|last4=Ballard|first4=R.|last5=Carranza|first5=A.|last6=Cordoba|first6=D.|last7=Cox|first7=C.|last8=Garcia|first8=V. M. D.|last9=Francheteau|first9=J.|date=1980-03-28|title=East Pacific Rise: Hot Springs and Geophysical Experiments|journal=Science|language=en|volume=207|issue=4438|pages=1421–1433|doi=10.1126/science.207.4438.1421|issn=0036-8075|pmid=17779602|bibcode=1980Sci...207.1421S |s2cid=28363398 }}</ref> These discoveries revealed deep-sea ecosystems that exist without sunlight and are based on [[chemosynthesis]].<ref name=":0" />

===Exploration of RMS ''Titanic''===
''Alvin'' was involved in the exploration of the wreckage of {{Ship|RMS|Titanic}} in 1986. Launched from her support ship {{Ship|RV|Atlantis II}}, she carried Dr. [[Robert Ballard]] and two companions to the wreckage of the [[White Star Line]]r ''Titanic,'' which sank in 1912 after striking an [[iceberg]] while crossing the North Atlantic Ocean on her maiden voyage.

''Alvin'', accompanied by a small [[remotely operated vehicle]] (ROV) named ''[[Jason Jr.]]'', was able to conduct detailed photographic surveys and inspections of ''Titanic''{{'}}s wreckage. Many of the photographs of the expedition have been published in the magazine of the [[National Geographic Society]], which was a major sponsor of the expedition.

The Woods Hole Oceanographic Institution team involved in the ''Titanic'' expedition also explored the wreck of the {{USS|Scorpion|SSN-589}}, a {{sclass|Skipjack|submarine}} armed with [[Mark 45 torpedo|nuclear torpedoes]], which sank off the coast of the Azores in 1968 in uncertain circumstances. ''Alvin'' obtained photographic and other environmental monitoring data from the remains of ''Scorpion''.<!--Contrary to [https://www.telegraph.co.uk/news/2019671/Titanic-mission-was-cover-for-submarine-search.html The Telegraph], the wreck had been found in October 1968.-->

===Recent overhauls===
{{See also|Ship of Theseus}}
[[File:Alvin (DSV-2) and Atlantis II(2).jpg|thumb|Mountains in the Sea Expedition, 2004.]]
Over the years, ''Alvin'' has undergone many overhauls to improve its equipment and extend its lifetime. In 2001, among other equipment, motor controllers and computer systems were added. The current ''Alvin'' is the same as the original vessel in name and general design only. All components of the vessel, including the frame and personnel sphere, have been replaced at least once. ''Alvin'' is completely disassembled every three to five years for a complete inspection.<ref>{{cite web|url=http://www.whoi.edu/page.do?pid=8422|title=Human Occupied Vehicle Alvin|publisher=Woods Hole Oceanographic Institution|year=2012|access-date=5 August 2012|archive-date=3 January 2012|archive-url=https://web.archive.org/web/20120103211818/http://www.whoi.edu/page.do?pid=8422|url-status=dead}}</ref> A new robotic arm was added in 2006.

===2008 upgrade ===
In June 2008 construction started on a stronger, slightly larger personnel sphere which was used to upgrade ''Alvin'', before being used in an entirely new vehicle.<ref>{{cite web |url= https://www.nytimes.com/2008/08/26/science/26alvi.html?pagewanted=all |title= Forging a new sphere |first=William J. |last=Broad |date=26 August 2008 |work=[[The New York Times]] |page=F1}}</ref> The new sphere was designed, and then forged from solid titanium ingots in two equal halves at Ladish Forge, [[Cudahy, Wisconsin]]. Then the 15.5 tonnes of titanium was machined and assembled, utilizing five view ports (instead of the previous three) and is designed for depths of over {{convert|6000|m|abbr=on}}, where ''Alvin''{{'}}s original depth limit was {{convert|4500|m|abbr=on}}.<ref>Borel, Brooke, "Alvin Redux", ''Popular Science'', March 2013</ref> This, along with a general upgrade of support systems, instruments and materials. These upgrades allow ''Alvin'' to reach 98% of the ocean floor.<ref>{{cite web |url=http://www.ouramazingplanet.com/679-upgraded-submarine-could-reach-98-percent-of-ocean.html |title=Upgraded Sub Could Reach 98 Percent of Ocean Deep |first=Jeremy |last=Hsu |publisher=OurAmazingPlanet.com |date=16 December 2010 |access-date=5 August 2012 |archive-url=https://web.archive.org/web/20120723234241/http://www.ouramazingplanet.com/679-upgraded-submarine-could-reach-98-percent-of-ocean.html |archive-date=23 July 2012 }}</ref> 

===2011 to 2014 rebuild===
After one last dive to assess damage to the [[Gulf of Mexico]]'s seafloor after the [[Deepwater Horizon oil spill|''Deepwater Horizon'' disaster]], ''Alvin'' was refitted further, starting January 2011.<ref>{{cite news |url= https://www.bbc.co.uk/news/science-environment-11938904 |title=Ocean science giant ''Alvin'' set for upgrade |first=Jonathan |last=Amos |publisher=[[BBC News]] |date=16 December 2010 |access-date=5 August 2012 }}</ref> Alvin began an extensive rebuild, which featured new cameras, lighting, and an enlarged titanium personnel sphere. This three-and-a-half-year effort to upgrade the vessel implemented the core infrastructure to eventually increase its depth capability from {{convert|4,500|meters|feet}} to {{convert|6,500|meters|feet}}.<ref name="2022_seatrials">{{cite web |url= https://www.whoi.edu/oceanus/feature/who-is-alvin-and-what-are-sea-trials |title=Who is Alvin |publisher=Woods Hole Oceanographic Institution |year=2022 |access-date=23 June 2023 |url-status=live |archive-url=https://web.archive.org/web/20230325014149/https://www.whoi.edu/oceanus/feature/who-is-alvin-and-what-are-sea-trials/ |archive-date=25 March 2023}}</ref> In 2014, an extensively refitted ''Alvin'' conducted verification testing in the Gulf of Mexico, and was certified to return to service.<ref>{{cite web |url= http://alvinverification.whoi.edu/not-your-grandfathers-cadillac/ |title=Not Your Grandfather's Cadillac |first=Lonny |last=Lippsett |date=13 March 2014 |publisher=[[Woods Hole Oceanographic Institution]] |access-date=18 March 2014}}</ref><ref name="2014 retrun">{{cite web |url= https://www.nsf.gov/news/news_summ.jsp?cntn_id=130226&org=NSF |title=Alvin cleared to return to service |publisher=National Science Foundation |year=2014 |access-date=24 June 2023 |url-status=live |archive-url=https://web.archive.org/web/20230624061518/https://www.nsf.gov/news/news_summ.jsp?cntn_id=130226&org=NSF |archive-date=24 June 2023}}</ref> In March and April 2014, ''Alvin'' was used to explore the site of the 2010 Deepwater Horizon oil spill.<ref>{{Citation
 | last =Juhasz
 | first = Antonia 
 | author-link = Antonia Juhasz
 | title = The Deepwater Horizon Spill, Four Years On
 | magazine = Harper's
 | date = 2014-04-01
 | url = http://harpers.org/blog/2014/04/the-deepwater-horizon-spill-four-years-on/
}}</ref>

===2020 to 2022 upgrade===
Starting in 2020, the second phase to upgrade Alvin for {{convert|6500|meters|feet}} operation began; the 2014 rebuild with new, larger titanium, personnel hull and rebuilt structural frame being the first phase.  In this phase, Alvin received new titanium ballast spheres, a second Schilling manipulator arm, a 4K imaging system, several new syntactic foam modules, an upgrade to the hydraulic system, and new thrusters.  During 2022, Alvin successfully completed sea trials and was certified for operating down to 6500 meters.<ref name="2022_seatrials" />

==Current status==
As of 2024, ''Alvin'' is in active service, operated by the Woods Hole Oceanographic Institution. The research ship [[RV Atlantis (AGOR-25)|RV ''Atlantis'']] serves as its support ship.<ref>{{cite book |last1=Casey |first1=Susan |title=The Underworld: Journeys to the Depths of the Ocean |date=2023 |publisher=Diversified Publishing |isbn=978-0593744253}}</ref>

== Operation ==
[[File:ALVIN Panorama.jpg|thumb|center|800px|DSV ''Alvin'' on the fantail (stern) of {{Ship|RV|Atlantis|AGOR-25|6}} following a dive. On the right side of the photograph the A-frame crane can be seen that lowers ''Alvin'' into the water and lifts it back on board, and on the left, ''Alvin''{{'}}s hangar.]]
Like most deep submergence vehicles, ''Alvin'' is normally transported on board its support vessel. It is launched shortly before a dive, and recovered after the dive, using a suitable {{diving term|launch and recovery system}} (LARS) mounted on the support vessel. The support vessel is usually the [[RV Atlantis (AGOR-25)|R/V ''Atlantis'']], but several others have been used.

''Alvin'' uses four {{convert|208|lb|adj=on}} steel weights (~1.7 cubic feet of steel) to provide negative buoyancy for the trip to the ocean floor. ''Alvin'' contains a [[ballast and trim system]], but the steel weights allow deep dives to be achieved more rapidly. These weights are jettisoned on each dive and left at the bottom.<ref>{{cite web|url=http://www.marinetech.org/nine_degrees/expedition.php?phase=log&date=942912000&base=expo942864462&picnum=0 |title=Marine Advanced Technology Education (MATE) Center – Expedition Log |first=Mike |last=deGruy |publisher=marinetech.org |date=18 November 1999 |access-date=5 August 2012 |archive-url=https://web.archive.org/web/20120720081506/http://www.marinetech.org/nine_degrees/expedition.php?phase=log&date=942912000&base=expo942864462&picnum=0 |archive-date=20 July 2012 }}</ref><ref>{{cite journal |first=Amy E. |last=Nevala |url= http://www.whoi.edu/oceanus/viewArticle.do?id=5599 |title=Alvin's Pilots |journal=Oceanus |date=3 August 2005 |access-date=5 August 2012}}</ref>

== See also ==
* {{annotated link|Hydrothermal vent}}
* {{annotated link|Deep-submergence vehicle}}
* {{annotated link|Mid-ocean ridge}}
* {{annotated link|RISE project}}
* {{annotated link|Jack Corliss}}
* {{annotated link|Bruce P. Luyendyk}}
* {{annotated link|Bruce Strickrott}}
* {{annotated link|Kenneth C. Macdonald}}
* {{annotated link|Fred Spiess}}

===''Alvin''-class DSV===
* {{annotated link|DSV Turtle|''Turtle'' (DSV-3)}}
* {{annotated link|DSV Sea Cliff|''Sea Cliff'' (DSV-4)}}
* {{annotated link|DSV-5 Nemo|''Nemo'' (DSV-5)}}

===Other deep submergence vehicles===
{{div col}}
* {{annotated link|Aluminaut|''Aluminaut''}}
* {{annotated link|Trieste (bathyscaphe)|''Trieste''}}
* {{annotated link|Trieste II (Bathyscaphe)|''Trieste II''}} (DSV-1)
* {{annotated link|SP-350 Denise|SP-350 ''Denise''}}
* {{annotated link|Jiaolong (submersible)|''Jiaolong''}}
* {{annotated link|DSRV-1 Mystic|DSRV-1 ''Mystic''}}
* {{annotated link|DSRV-2 Avalon|DSRV-2 ''Avalon''}}
* {{annotated link|American submarine NR-1|''NR-1''}}
* {{annotated link|Mir (submersible)|''MIR 1'' and ''MIR 2''}}
* {{annotated link|Nautile|''Nautile''}}
* {{annotated link|Pisces-class deep submergence vehicle|''Pisces''-class deep submergence vehicle}}
* {{annotated link|Sea Pole-class bathyscaphe|''Sea Pole''-class bathyscaphe}}
* {{annotated link|Sea Pole-class bathyscaphe#Dragon class bathyscaphe|''Dragon'' class bathyscaphe}}
* {{annotated link|Sea Pole-class bathyscaphe#Harmony class bathyscaphe|''Harmony'' class bathyscaphe}}
* {{annotated link|DSV Shinkai 6500|DSV ''Shinkai 6500''}} 
* {{annotated link|DSV Shinkai 2000|''Shinkai 2000''}}
* {{annotated link|Deepsea Challenger|''Deepsea Challenger''}}
* {{annotated link|DSV Limiting Factor|''DSV Limiting Factor''}}
{{div col end}}

==References==
{{Reflist|refs=

<ref name="Strickrott 2017" >{{cite journal |url=https://www.whoi.edu/wp-content/uploads/2019/03/JOT_Article_250024.pdf |title=The Deep Submergence Vehicle Alvin |first=W. Bruce |last=Strickrott |journal=The Journal of Ocean Technology |volume=12 |issue=1 |date=2017 }}</ref>

}}

== Further reading ==
* {{cite book | title=Water Baby: The Story of Alvin | author= Kaharl, Victoria A. | date=1 October 1990 | isbn=0-19-506191-8 | publisher=Oxford University Press, USA}}
* {{cite book | title=The Restless Sea: Exploring the World Beneath the Waves | author=Kunzig, Robert | publisher=W. W. Norton & Company | edition=1st | date=1 March 1999 | isbn=0-393-04562-5 | url-access=registration | url=https://archive.org/details/restlessseaexplo00kunz }}

== External links ==
{{Commons category|Alvin (DSV-2)}}
* {{official|https://www.whoi.edu/what-we-do/explore/underwater-vehicles/hov-alvin}}

{{physical oceanography|expanded=other}}
{{WHOI-Ships}}
{{1968 shipwrecks}}
{{Underwater diving|other}}
{{Authority control}}

{{DEFAULTSORT:Alvin}}
[[Category:1964 ships]]
[[Category:Alvin-class deep-submergence vehicles]]
[[Category:Maritime incidents in 1968]]
[[Category:Ships built in Minnesota]]
[[Category:United States submarine accidents]]
[[Category:Woods Hole Oceanographic Institution]]
[[Category:Research submarines of the United States]]