Submarines in the context of Autonomous underwater vehicle

Submarine navigation underwater requires special skills and technologies not needed by surface ships. The challenges of underwater navigation have become more important as submarines spend more time underwater, travelling greater distances and at higher speed. Military submarines travel underwater in an environment of total darkness with neither windows nor lights. Operating in stealth mode, they cannot use their active sonar systems to ping ahead for underwater hazards such as undersea mountains, drilling rigs or other submarines. Surfacing to obtain navigational fixes is precluded by pervasive anti-submarine warfare detection systems such as radar and satellite surveillance. Antenna masts and antenna-equipped periscopes can be raised to obtain navigational signals but in areas of heavy surveillance, only for a few seconds or minutes; current radar technology can detect even a slender periscope while submarine shadows may be plainly visible from the air.

The École navale (French pronunciation: [ekɔl naval]) is the French naval academy, in charge of the education of the officers of the French Navy. They are educated at the academy for responsibilities onboard surface ships and submarines, in French Naval Aviation, with the fusiliers marins and commandos, and on the general staff. It is also an engineering school, delivering a full scientific and technical curriculum as part of its officer training.

The École navale and its research institute (IRENAV) are in Lanvéoc-Poulmic, south of the roadstead of Brest.

Potassium superoxide is an inorganic compound with the formula KO₂. It is a yellow paramagnetic solid that decomposes in moist air. It is a rare example of a stable salt of the superoxide anion. It is used as a CO₂ scrubber, H₂O dehumidifier, and O₂ generator in rebreathers, spacecraft, submarines, and spacesuits.

USS Freedom (LCS-1) is the lead ship of the Freedom-class littoral combat ship for the United States Navy. She is the third vessel to be so named after the concept of freedom. She is the design competitor produced by the Lockheed Martin consortium, in competition with the General Dynamics–designed USS Independence. She was officially accepted by the Supervisor of Shipbuilding Gulf Coast, on behalf of the US Navy, from the Lockheed Martin/Marinette Marine/Gibbs and Cox team, in Marinette, Wisconsin, on 18 September 2008.

She is designed for a variety of missions in shallow waters, minesweeping and humanitarian relief, capable against submarines and small ships, but not designed to take on large warships. The ship is a semi-planing monohull design capable of over 40 knots (74 km/h; 46 mph).

Acoustic quieting is the process of making machinery quieter by damping vibrations to prevent them from reaching an observer. Machinery vibrates, causing sound waves in air, hydroacoustic waves in water, and mechanical stresses in solid matter. Quieting is achieved by absorbing the vibrational energy or minimizing the source of the vibration. It may also be redirected away from an observer.

One of the major reasons for the development of acoustic quieting techniques was for making submarines difficult to detect by sonar. This military goal of the mid- and late-twentieth century allowed the technology to be adapted to many industries and products, such as computers (e.g. hard drive technology), automobiles (e.g. motor mounts), and even sporting goods (e.g. golf clubs).

There are three major types of submarines in the United States Navy: ballistic missile submarines, attack submarines, and cruise missile submarines. All submarines currently in the U.S. Navy are nuclear-powered. Ballistic missile submarines have a single strategic mission of carrying nuclear submarine-launched ballistic missiles. Attack submarines have several tactical missions, including sinking ships and subs, launching cruise missiles, and gathering intelligence. Cruise missile submarines perform many of the same missions as attack submarines, but with a focus on their ability to carry and launch larger quantities of cruise missiles than typical attack submarines.

The submarine has a long history in the United States, beginning with the Turtle, the world's first submersible with a documented record of use in combat.