This term is often used to separate such vehicles from submarines. However, in common usage, the phrase "submarine" can be used to describe a ship that, by technical definition, is actually a submersible.
There are many types of such equipment, including both homemade and industrialized craft, otherwise known as remote controlled vehicles or ROVs. They have many applications worldwide, especially in areas such as oceanography, underwater archaeology, ocean exploration, tourism, equipment maintenance and restoration, and underwater videography.
History
The first submarine was designed and built by American inventor David Bushnell in 1775 as a means of delivering explosive charges to enemy ships during the American Revolutionary War. The device, dubbed "Bushnell's Turtle", was an oval vessel made of wood and copper. It contains tanks filled with water (for immersion), and then they were emptied using a manualpump to float to the surface. The operator used two hand-held propellers to move vertically or laterally underwater. The craft had small glass windows on top and luminescent wood attached to the body so it could be operated in the dark.
The Bushnell Turtle was first commissioned on 7 September 1776 in New York Harbor to attack the British flagship HMS Eagle. At the time, Sergeant Ezra Lee was operating this submersible. Lee successfully brought the Turtle to the underside of the Eagle's hull, but was unable to set the charge due to strong water currents. However, the history of these modes of transport did not end there.
Features
Besides size, the main technical difference between a submersible and a submarine is that the former is not fully autonomous and may rely on a support facility or vessel to replenish fuel and breathing gases. Some vehicles operate on a "tether" or "umbilical cord" while remaining connected to the tender (submarine, surface ship, or platform). They tend to have a shorter range and work mostly underwater as most are useless on the surface. Submarines (submarines) are capable of submerging more than 10 km (6 miles) below the surface of the water.
Submarines can be relatively small, contain only a small crew, and have no living quarters. They often have a very nimble design fitted with propeller screws orpumps.
Technology
There are five main technologies used in the design of submersibles. Unipolar devices have a pressurized body, while their passengers are under normal atmospheric pressure. They easily withstand high water pressure, which is many times higher than the internal one.
Another technology called ambient pressure maintains the same load both inside and outside the vessel. This reduces the pressure the hull must withstand.
The third technology is the "wet submarine". The term refers to a vehicle with a flooded interior. In both water and atmospheric environments, there is no need to use SCUBA equipment, passengers can breathe normally without wearing any additional devices.
Records
Due to cable traction, underwater vehicles can dive to great depths. Bathyscaphe Trieste was the first to reach the deepest part of the ocean (nearly 11 km (7 miles) below the surface) at the bottom of the Mariana Trench in 1960.
China with its Jiaolong project in 2002 was the fifth country to send a man 3,500 meters below sea level, following the US, France, Russia and Japan. On the morning of June 22, 2012, the Jiaolong loading and unloading facility set a deep dive record when three people descended 22,844 feet (6,963 meters) into the Pacific Ocean.
Among the best-known and longest-running submersibles is the deep-sea research vessel DSV Alvin, which is manned by 3 and capable of diving to depths of up to 4,500 meters (14,800 feet). It is owned by the United States Navy, operated by WHOI and has completed over 4,400 dives since 2011.
James Cameron made a record dive to the bottom of the Challenger Deep, the deepest known point of the Mariana Trench, on March 26, 2012. Cameron's submarine was called the Deepsea Challenger and reached a depth of 10,908 meters (35,787 feet).
Latest news
Most recently, Florida private firms have released a series of Triton Submarines. SEAmagine Hydrospace, Sub Aviator Systems (or SAS) and the Dutch firm Worx have developed small submarines for tourism and exploration.
A Canadian company called Sportsub has been building personal recreational submarines with open floor structures (partially flooded cockpits) since 1986.
Functional Views
Small unmanned underwater vehicles called "Marine Remotely Operated Vehicles", or MROVs, are widely used today to operate in water that is too deep or too dangerous for divers.
Such vehicles help repair offshore oil platforms and attach cables to sunken ships to raise them. These remote controlled vehicles are attached by a tether (thick cable that provides power and communication) to a control center on the ship. Operators on the ship watch the video images sent back from the robot and can control the vehicle's propellers and arm. The submerged Titanic was studied by just such a vehicle.
Bathyscaphes
The bathyscaphe is a self-propelled deep-sea submersible submarine consisting of a crew cabin, similar to a bathysphere, but suspended below a float rather than by a surface cable, as in the classic bathysphere design. Many see it as a type of self-propelled submersible.
Its float is filled with gasoline, easily accessible, buoyant and very durable. The incompressibility of the fuel means that tanks can be constructed very easily as the pressures inside and outside the tanks are balanced. Also, the tanks do not have the task of fully withstanding any pressure drops, while the cockpit is designed to resist a huge load. Buoyancy on the surface can be easily reduced by replacing gasoline with water, which is denser.
Etymology
Auguste Picard, inventor of the first bathyscaphe, coined the name "bathyscaphe" using the ancient Greek words βαθύς bathys ("deep") and σκάφος skaphos ("vessel" / "ship").
Operation
To descend, the bathyscaphe floods air tanks with sea water. But unlike a submarine, the liquid in its flooded tanks cannot be dislodged with compressed air to rise. This is due to the fact that the water pressure at depths for whichthe ship was designed to work, too large.
For example, the pressure at the bottom of the Challenger Deep - the submersible that James Cameron himself sailed on - is more than seven times the pressure in a standard Type H compressed gas cylinder. This submersible used iron weights for balance. Containers with them consist of one or more cylinders that are open at the bottom throughout the dive, and the cargo is held in place by an electromagnet. It is a fail safe device as it does not require power boost.
History of bathyscaphes
The first bathyscaphe was named FNRS-2 - after the National Recreational Research Foundation - and was built in Belgium from 1946 to 1948 by Auguste Picard. FNRS-1 was the balloon used to lift Picard into the stratosphere in 1938.
The movement of the first bathyscaphe was provided by battery-powered electric motors. The float amounted to 37,850 liters of aviation gasoline. It did not have an access tunnel. The sphere had to be loaded and unloaded on deck. The first voyages are described in detail in Jacques Cousteau's book The Quiet World. As the story goes, "the ship withstood the pressure of the depths serenely, but was destroyed by a slight squall." The FNRS-3 was a new submersible using the crew sphere from the damaged FNRS-2 and a new larger 75.700 liter float.
The second Piccard bathyscaphe was bought by the US Navy from Italy in 1957. It had two cargoes with ballast water and eleven buoyancy tanks,containing 120,000 liters of gasoline. Later, the Poseidon submersible was invented.
In 1960, a submersible carrying Picard's son Jacques and Lieutenant Don Walsh reached the deepest known location on Earth's surface, the Challenger Deep in the Mariana Trench. Onboard systems indicated a depth of 37,800 feet (11,521 m), but this was later corrected to 35,813 feet (10,916 m) to account for changes caused by salinity and temperature.
The apparatus was equipped with a powerful source of energy, which, by illuminating a small fish like a flounder, raised the question of whether life existed at such a depth in the complete absence of light. The crew of the submersible noted that the bottom consisted of diatomaceous silt and reported seeing some type of sole-like flounder, about 1 foot long and 6 inches across, lying on the seafloor.
In 1995, the Japanese sent an autonomous underwater vehicle to the same depth, but it was later lost at sea. In 2009, a team from the Woods Hole Oceanographic Institution sent a robotic submarine named Nereus to the bottom of the trench.
Invention of the bathysphere
The Bathysphere (from the Greek βαθύς, bana, "deep" and σφαῖρα, sfire, "sphere") was a unique spherical deep-sea submarine that was remotely controlled and lowered into the ocean by a tether. She was used on a series of dives off the coast of Bermuda from 1930 to 1934.
The bathysphere was designed in 1928and 1929 by the American engineer Otis Barton and became famous due to the fact that the naturalist William Beebe used it to study underwater wildlife. By its structure, the bathysphere is close to a torpedo submersible.
