Editing DSV Alvin (section)

== 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>