A deep-submergence vehicle (DSV) is a deep-diving crewed submarine that is self-propelled.
Several navies operate vehicles that can be accurately described as DSVs.
DSVs are commonly divided into two types: research DSVs, which are used for exploration and surveying, and DSRVs (Deep Submergence Rescue Vehicle), which can be used for rescuing the crew of a sunken navy submarine, clandestine (espionage) missions (primarily installing wiretaps on undersea cables), or both.
DSRVs are equipped with docking chambers to allow personnel ingress and egress via a manhole.
The real-life feasibility of any DSRV-based rescue attempt is hotly debated, because the few available docking chambers of a stricken submarine may be flooded, trapping the sailors still alive in other dry compartments.
The only attempt to rescue a stricken submarine with these so far (the Russian submarine Kursk) ended in failure as the entire crew who survived the explosion had either suffocated or burned to death before the rescuers could get there.
Because of these difficulties, the use of integrated crew escape capsules, detachable conning towers, or both have gained favour in military submarine design during the last two decades.
DSRVs that remain in use are primarily relegated to clandestine missions and undersea military equipment maintenance.
The rapid development of safe, cost-saving ROV technology has also rendered some DSVs obsolete.
Strictly speaking, bathyscaphes are not submarines because they have minimal mobility and are built like a balloon, using a habitable spherical pressure vessel hung under a liquid hydrocarbon filled float drum.
In a DSV/DSRV, the passenger compartment and the ballast tank functionality is incorporated into a single structure to afford more habitable space (up to 24 people in the case of a DSRV).
Most DSV/DSRV vehicles are powered by traditional electric battery propulsion and have very limited endurance, while few (like NR-1 or AS-12/31) are/were nuclear-powered, and could sustain much longer missions.
Plans have been made to equip DSVs with LOX Stirling engines but none have been realized so far due to cost and maintenance considerations.
All DSVs are dependent upon a surface support ship or a mother submarine, that can piggyback or tow them (in case of the NR-1) to the scene of operations.
Some DSRV vessels are air transportable in very large military cargo planes to speed up deployment in case of emergency rescue missions.thumb|Historical Deep Submergence Vehicles List of deep submergence vehicles
''Trieste''-class bathyscaphe
; FNRS-2 : the predecessor to Trieste ; FNRS-3 : contemporary of Trieste I ; DSV-0 Trieste : the X-1 Trieste bathyscaphe has reached Challenger Deep, the world's deepest seabed.
It was retired in 1966.
; DSV-1 X-2 Trieste II : an updated bathyscaphe design, it participated in clandestine missions.
Trieste II was retired in 1984. '
'Alvin''-class submarine
Alvin, owned by the Office of Naval Research (ONR) is operated under agreement by the National Deep Submergence Facility at the Woods Hole Oceanographic Institution (WHOI), where it conducts science oriented missions funded by the National Science Foundation (NSF), National Oceanic and Atmospheric Administration (NOAA) and ONR.
Alvin has a maximum depth capability of  and operates from R/V Atlantis, an AGOR-23 class vessel owned by the ONR and operated by WHOI under a charter party agreement.
The NSF has committed to the construction of a replacement sub with enhanced capabilities and  depth capability to replace Alvin, which will be retired upon its completion.
; DSV-2 Alvin : a deep diving sub, launched June 1964, has a  depth capability, extensively modified and rebuilt, owned by USN and operated by WHOI.
; DSV-3 Turtle : Alvins identical sibling, launched December 1968, retired 1998, USN.
; DSV-4 Sea Cliff : another Alvin-class DSV sub, launched December 1968, retired 1998, returned to active service on September 30, 2002, Sea Cliff has  depth capability, USN.
; DSV-5 Nemo : another Alvin-class DSV sub, launched June 1970, retired 1998, USN. '
'Star''-class DSV
; Star II ; Star III
Both Star II and Star III were built by General Dynamics Electric Boat Division in Groton, Connecticut.
Both were launched on May 3, 1966 and were used for civilian research.
NR-1–class DSVN
; NR-1 : a decommissioned US Navy nuclear powered research and clandestine DSV submarine, which could roll on the seabed using large balloon wheels. '
'Aluminaut''
; Aluminaut : a DSV made completely of aluminum by the Reynolds Metals Aluminum Company, for the US Navy, once held the submarine deep diving record.
It is no longer operational. '
'Deepsea Challenger''
; Deepsea Challenger : a DSV made by the Acheron Project Pty Ltd, has reached Challenger Deep, the world's deepest seabed. '
'Limiting Factor''
; DSV Limiting Factor : a submersible commissioned by Caladan Oceanic and designed and built by Triton Submarines of Sebastian, Florida.
On December 19, 2018 it was the first crewed submersible to reach the bottom of the Atlantic Ocean, or 8,376 meters in the Brownson Deep, thus making it the deepest diving, currently operational submersible.
In August 2019, the submersible and its pilot, Victor Vescovo, completed the "Five Deeps Expedition" with its support ship, the DSSV Pressure Drop, becoming the first submersible to visit the bottom of all five of the world's oceans.
Earlier that same month, a team of explorers and scientists used Limiting Factor to visit the wreck of the RMS Titanic in the North Atlantic Ocean.
On March 31, 2021, Caladan Oceanic announced having re-located, surveyed, and filmed the wreck of the World War II destroyer , sunk in the Battle off Samar.
Johnston lies at depth of , making Limiting Factors expedition the deepest wreck dive in history.
Priz-class DSRV
; Priz : a DSRV class of five ships built by the USSR and Russia.
The titanium-hulled Priz class are capable of diving to .
These mini-submarines can ferry up to 20 people for very brief periods of time (in case of a rescue mission) or operate submerged for two to three days with a regular crew of three to four specialists.
In early 2005, the Russian AS-28 Priz vessel was trapped undersea and subsequently freed by a British ROV in a successful international rescue effort.
Mir
; Mir : a strictly civilian (research) class of two DSVs which were manufactured in Finland for the USSR.
These bathyscaphe-derived vessels can carry three people down to depths of .
After visiting and filming the RMS Titanic's wreck, the two Mir submersibles and their support ship were loaned to a US Pacific trench surveying mission in the late 1990s and made important discoveries concerning sulphuric based life in "black smokers".
Kalitka-class DSVN
; AS-12 : a Russian counterpart to the American NR-1 clandestine nuclear DSV, is a relatively large, deep-diving nuclear submarine of 2,000 tons submerged displacement that is intended for oceanographic research and clandestine missions.
It has a titanium pressure hull consisting of several conjoined spheres and able to withstand tremendous pressure — during the 2012 research mission it routinely dove to , with maximum depth being said to be approximately .
Despite the three-month mission time allowed by its nuclear reactor and ample food stores it usually operates in conjunction with a specialized tender, a refurbished Delta III-class submarine BS-136 Orenburg, which has its missile shafts removed and fitted with a special docking cradle on its bottom. '
'Konsul''-class DSV
; Konsul : a class of Russian military DSVs currently deployed onboard the Russian oceanographic research ship Yantar.
It is reported that the submersible and its sister sub Rus are used to conduct seafloor surveillance of marine communications cables and western underwater surveillance devices.
They are somewhat smaller than the Mirs, accommodating a crew of two instead of three, but are purely domestically produced vessels and have a higher maximum depth due to their titanium pressure hulls: during the tests the original Konsul dove to . '
'Nautile''
; Nautile : a DSV owned by Ifremer, the French Research Institute for Exploitation of the Sea.
The titanium-hulled Nautile is capable of diving to . '
'Shinkai''
; DSV Shinkai : JAMSTEC (Japan Agency for Marine-Earth Science and Technology) operates a DSV-series called Shinkai ("Deep Sea").
The latest DSV is Shinkai 6500 which can submerge to  with three crew members.
JAMSTEC was operating a ROV called Kaikō, which was able to submerge to , but was lost at sea in May 2003. '
'Pisces''-class DSV
; Pisces-class DSV : three-person research submersibles built by International Hydrodynamics of Vancouver in British Columbia with a maximum operating depth of  capable of dive durations of 7 to 10 hours.
A total of 10 were built and are representative of late 1960s deep-ocean submersible design.
Two (Pisces IV and Pisces V) are currently operated by National Oceanic and Atmospheric Administration and the first production vehicle is on display in Vancouver.
Pisces VI is undergoing retrofit. '
'Sea Pole''-class bathyscaphe
Bathyscaphe series designed by the People's Republic of China, and there are three derivatives known to exist by 2010: ; Sea Pole-class bathyscaphe : 2 built ; Jiaolong-class bathyscaphe : Developed from Sea Pole class, 1 built.
; Harmony-class bathyscaphe : Developed from Jiaolong class, 1 built. '
'Fendouzhe'' DSV
; Fendouzhe, or Striver-class : a Chinese DSV that dove to an estimated depth of 10,909 meters in the Mariana Trench on November 10, 2020, the deepest ever for a Chinese submersible.
It was supported by its mother ship, the Tansuo-1 (Exploration-1) and its development began in 2016.
The chief designer of the sub, Liu Yeyao, and two other Chinese oceanauts made the descent in what was the first three-person, welded titanium capsule to venture to full ocean depth. '
'Shenhai Yongshi'' DSV
; Shenhai Yongshi or "Deep sea warrior" : developed by China Shipbuilding Industry Corporation in 2017 and capable of diving up to a depth of 4,500 meters. '
'Ictineu 3''
; Ictineu 3 : a three-person crewed DSV.
The hull is made of inox steel and it has a large  semi-spheric acrylic glass viewport.
It is designed to reach depths of , thus being the ninth-deepest submersible, and it is capable of diving during 10 hours using li-ion batteries. '
'Matsya 6000''
; Matsya 6000 DSV : an Indian under-development manned deep-submergence vehicle intended to be utilised for deep sea exploration of rare minerals in the Indian Ocean.
It is capable of diving upto a depth of 6,000 m.
First unmanned trail was conducted on 27 October 2021 where the 'personnel sphere' was lowered upto a depth of 600 m, off the coast of Chennai.
Other DSV bathyscaphes
; Bathyscaphe Archimède : French-made bathyscaphe, operated around the time of the Trieste.
; FNRS-4 Deepest explorers
DSV Limiting Factor11,000 m
Bathyscaphe Trieste11,000 m
Deepsea Challenger11,000 m
Fendouzhe11,000 m
Archimède9,500 m
Jiaolong7,000 m
DSV Shinkai 65006,500 m
Konsul6,500 m
DSV Sea Cliff6,000m
MIR6,000 m
Nautile6,000 m
Figures rounded to nearest 500 metres
References
External links
"Deep Submergence Vehicle (S-P)".
Naval Vessel Register.
"Deep Submergence Rescue Vehicle (S-P)".
Naval Vessel Register.
https://web.archive.org/web/20041017224027/http://www.chinfo.navy.mil/navpalib/factfile/ships/ship-dsrv.html
"Research Vessels and Vehicles".
Japan Agency for Marine-Earth Science and Technology.
"Robot sub reaches deepest ocean".
BBC News, 3 June 2009.
