Submarine
Both the US and British navies operate nuclear-powered submarines that deploy for periods of six months or longer. Other navies that permit women to serve on submarines operate conventionally powered submarines, which deploy for much shorter periods—usually only for a few months. Prior to the change by the US, no nation using nuclear submarines permitted women to serve on board.
In 2011, the first class of female submarine officers graduated from Naval Submarine School's Submarine Officer Basic Course (SOBC) at the Naval Submarine Base New London. Additionally, more senior ranking and experienced female supply officers from the surface warfare specialty attended SOBC as well, proceeding to fleet Ballistic Missile (SSBN) and Guided Missile (SSGN) submarines along with the new female submarine line officers beginning in late 2011. By late 2011, several women were assigned to the Ohio-class ballistic missile submarine USS Wyoming. On 15 October 2013, the US Navy announced that two of the smaller Virginia-class attack submarines, USS Virginia and USS Minnesota, would have female crew-members by January 2015.
In 2020, Japan's national naval submarine academy accepted its first female candidate.

Abandoning the vessel: In an emergency, submarines can contact other ships to assist in rescue, and pick up the crew when they abandon ship. The crew can use escape sets such as the Submarine Escape Immersion Equipment to abandon the submarine via an escape trunk, which is a small airlock compartment that provides a route for crew to escape from a downed submarine at ambient pressure in small groups, while minimising the amount of water admitted to the submarine. The crew can avoid lung injury from over-expansion of air in the lungs due to the pressure change known as pulmonary barotrauma by maintaining an open airway and exhaling during the ascent. Following escape from a pressurized submarine, in which the air pressure is higher than atmospheric due to water ingress or other reasons, the crew is at risk of developing decompression sickness on return to surface pressure.
An alternative escape means is via a deep-submergence rescue vehicle that can dock onto the disabled submarine, establish a seal around the escape hatch, and transfer personnel at the same pressure as the interior of the submarine. If the submarine has been pressurised the survivors can lock into a decompression chamber on the submarine rescue ship and transfer under pressure for safe surface decompression.

See also: 

By country: List of submarine operators
Australia – Collins-class submarine
Bangladesh- Submarines of the Bangladesh Navy
Britain – List of submarines of the Royal Navy, List of submarine classes of the Royal Navy
China – Submarines of the People's Liberation Army Navy
France – Submarines in the French Navy, List of submarines of the French Navy, List of French submarine classes and types
Germany – List of U-boats of Germany
India – Submarines of the Indian Navy
Israel – Dolphin-class submarine
Japan – Imperial Japanese Navy submarines, List of combatant ship classes of the Japan Maritime Self-Defense Force § SS : Submarine
The Netherlands – List of submarines of the Netherlands
Pakistan – List of active Pakistan Navy ships § Submarines
Romania – Romanian submarines of World War II
Russia – List of Soviet and Russian submarine classes, Future Russian submarines
Soviet Union – List of ships of the Soviet Navy § Submarines
Spain – List of submarines of the Spanish Navy
Singapore – Republic of Singapore Navy § Submarines
Turkey – List of submarines of the Turkish Navy
United States – Submarines in the US Navy, List of submarines of the US Navy, List of US submarine classes, Naval Submarine Medical Research Laboratory

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Bibliography: 

External links: 
U.S. patent 708,553 – Submarine boat
The Submarine: Part II: Construction (1955) is available for free viewing and download at the Internet Archive
The Fleet Type Submarine Online US Navy submarine training manuals, 1944–1946
American Society of Safety Engineers. Journal of Professional Safety. Submarine Accidents: A 60-Year Statistical Assessment. C. Tingle. September 2009. pp. 31–39. Ordering full article; or Reproduction without graphics/tables