A deep-submergence vehicle (DSV) is a deep-diving crewed submersible 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 vehicles), which are intended to be used for rescuing the crew of a sunken navy submarine, clandestine (espionage) missions (primarily installing wiretaps on undersea communications cables), or both. DSRVs are equipped with docking chambers to allow personnel ingress and egress via a manhole. 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 a 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 to date (2023) are dependent on 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.

List of deep submergence vehicles

Trieste-class bathyscaphes

Alvin-class submersibles

Originally designed for 6000 ft operation, and initially built to a similar design, Alvin and her sister submersibles have been subsequently, independently upgraded. Utilizing syntactic foam, these submersibles were more compact and maneuverable than earlier bathyscaphes like Trieste, although not as deep diving.

Star-class DSV

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

Aluminaut

Deepsea Challenger

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 USS Johnston (DD-557), sunk on October 25, 1944, in the Battle off Samar (in the Philippine Sea off Samar Island). Johnston lies at depth of 21,180 ft, making Limiting Factor's expedition the deepest wreck dive in history.

Priz-class DSRV

Mir

Kalitka-class DSVN

Konsul-class DSV

Nautile

Shinkai

Pisces-class DSV

Sea Pole-class bathyscaphe

Bathyscaphe series designed by the People's Republic of China, and there are three derivatives known to exist by 2010:

Fendouzhe DSV

Deep Sea Warrior bathyscaphe

Ictineu 3

Matsya 6000

Titan

Titan, previously called Cyclops 2, was an experimental submersible that imploded while transporting tourists to visit the wreckage of the Titanic in 2023. The submersible was created and operated by OceanGate. It was the first privately-owned submersible with a claimed maximum depth of 4,000 m (13,000 ft), and the first completed crewed submersible with a hull constructed of titanium and carbon fiber composite materials. After testing with dives to its maximum intended depth in 2018 and 2019, the original composite hull of Titan developed fatigue damage and was replaced by 2021. In that year, OceanGate began transporting paying customers to the wreck of the Titanic, completing several dives to the wreck site in 2021 and 2022. On June 18, 2023, Titan imploded during a dive to the Titanic. All five occupants of the submersible were killed. OceanGate had lost contact with Titan and contacted authorities later that day after the submersible was overdue for return. A massive international search and rescue operation ensued and ended on June 22, when debris from Titan was discovered about 1,600 feet (500 metres) from the bow of the Titanic.

Other DSV bathyscaphes

Deepest explorers