Bathyscaphe
Overview
 
A bathyscaphe (icon or ˈ) is a free-diving self-propelled deep-sea submersible
Submersible
A submersible is a small vehicle designed to operate underwater. The term submersible is often used to differentiate from other underwater vehicles known as submarines, in that a submarine is a fully autonomous craft, capable of renewing its own power and breathing air, whereas a submersible is...

, consisting of a crew cabin similar to a bathysphere, but suspended below a float rather than from a surface cable, as in the classic bathysphere design.

The float is filled with gasoline because this is readily available, buoyant, and for all practical purposes, incompressible. The incompressibility of the gasoline means the tanks can be very lightly constructed as the pressure inside and outside of the tanks equalises and they are not required to withstand any pressure differential at all.
Unanswered Questions
Encyclopedia
A bathyscaphe (icon or ˈ) is a free-diving self-propelled deep-sea submersible
Submersible
A submersible is a small vehicle designed to operate underwater. The term submersible is often used to differentiate from other underwater vehicles known as submarines, in that a submarine is a fully autonomous craft, capable of renewing its own power and breathing air, whereas a submersible is...

, consisting of a crew cabin similar to a bathysphere, but suspended below a float rather than from a surface cable, as in the classic bathysphere design.

The float is filled with gasoline because this is readily available, buoyant, and for all practical purposes, incompressible. The incompressibility of the gasoline means the tanks can be very lightly constructed as the pressure inside and outside of the tanks equalises and they are not required to withstand any pressure differential at all. By contrast the crew cabin must withstand a huge pressure differential and is massively built. Buoyancy
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...

 can be trimmed easily by replacing gasoline with water, which is denser.

Auguste Piccard
Auguste Piccard
Auguste Antoine Piccard was a Swiss physicist, inventor and explorer.-Biography:Piccard and his twin brother Jean Felix were born in Basel, Switzerland...

, inventor of the first bathyscaphe, composed the name bathyscaphe using the Ancient Greek words βαθύς bathys ("deep") and σκάφος skaphos ("ship").

Mode of operation

To descend, a bathyscaphe floods air tanks with sea water, but unlike a submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 the water in the flooded tanks cannot be displaced with compressed air to ascend, because the water pressures at the depths for which the craft was designed to operate are too great. For example, the pressure at the bottom of the Challenger Deep
Challenger Deep
The Challenger Deep is the deepest known point in the oceans, with a depth of to by direct measurement from submersibles, and slightly more by sonar bathymetry . It is located at the southern end of the Mariana Trench near the Mariana Islands group...

 is more than seven times that in a standard "H-type" compressed gas cylinder
Gas cylinder
A gas cylinder is a pressure vessel used to store gases at above atmospheric pressure. High pressure gas cylinders are also called bottles. Although they are sometimes colloquially called "tanks", this is technically incorrect, as a tank is a vessel used to store liquids at ambient pressure and...

. Instead, ballast in the form of iron shot
Iron shot
There are several types and uses of Iron shot*Small round iron balls used as projectiles.*Used as a simple weight.*Large ball, 7.26 kg for men and 4 kg for women, used in the sporting event shot put....

 is released to ascend, the shot being lost to the ocean floor. The iron shot containers are in the form of one or more hoppers which are open at the bottom throughout the dive, the iron shot being held in place by an electromagnet at the neck. This is a fail-safe
Fail-safe
A fail-safe or fail-secure device is one that, in the event of failure, responds in a way that will cause no harm, or at least a minimum of harm, to other devices or danger to personnel....

 device as it requires no power to ascend; in fact, in the event of a power failure, shot runs out by gravity and ascent is automatic.

History of development

The first bathyscaphe was dubbed FNRS-2
FNRS-2
The FNRS-2 was the first bathyscaphe. It was created by Auguste Piccard. Work started in 1937 but was interrupted by World War II. The deep-diving submarine was finished in 1948. The bathyscaphe was named after the Belgian Fonds National de la Recherche Scientifique , the funding organization for...

, named after the Fonds National de la Recherche Scientifique
NFWO
The National Fund for Scientific Research is a government institution in Belgium for supporting scientific research...

, and built in Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 from 1946 and 1948 by Auguste Piccard
Auguste Piccard
Auguste Antoine Piccard was a Swiss physicist, inventor and explorer.-Biography:Piccard and his twin brother Jean Felix were born in Basel, Switzerland...

. (FNRS-1 had been the balloon used for Piccard's ascent into the stratosphere in 1938). Propulsion was provided by battery
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

-driven electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

s. The float held 10,000 gallons of aviation gasoline. There was no access tunnel; the sphere had to be loaded and unloaded while on deck. The first journeys were detailed in the Jacques Cousteau book The Silent World. As described in the book, "the vessel had serenely endured the pressure of the depths, but had been destroyed in a minor squall". FNRS-3 was a new submersible, using the crew sphere from the damaged FNRS-2, and a new larger 20,000 gallon float.

Piccard's second bathyscaphe was actually a third vessel Trieste
Bathyscaphe Trieste
The Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe with a crew of two, which reached a record maximum depth of about , in the deepest known part of the Earth's oceans, the Challenger Deep, in the Mariana Trench near Guam, on January 23, 1960, crewed by Jacques Piccard ...

, which was purchased by the United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 from Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 in 1957. It had two water ballast tanks and eleven buoyancy tanks holding 120,000 litres of gasoline.

Accomplishments

In 1960 Trieste, carrying Piccard's son Jacques Piccard
Jacques Piccard
Jacques Piccard was a Swiss oceanographer and engineer, known for having developed underwater vehicles for studying ocean currents. He was one of only two people, along with Lt...

  and Lt. Don Walsh
Don Walsh
Don Walsh is an American oceanographer, explorer and marine policy specialist. He and Jacques Piccard were aboard the bathyscaphe Trieste when it made a record maximum descent into the Mariana Trench on 23 January 1960, the deepest point of the world's ocean...

, reached the deepest known point on the Earth's surface, the Challenger Deep
Challenger Deep
The Challenger Deep is the deepest known point in the oceans, with a depth of to by direct measurement from submersibles, and slightly more by sonar bathymetry . It is located at the southern end of the Mariana Trench near the Mariana Islands group...

, in the Mariana Trench
Mariana Trench
The Mariana Trench or Marianas Trench is the deepest part of the world's oceans. It is located in the western Pacific Ocean, to the east of the Mariana Islands. The trench is about long but has a mean width of only...

. As of 2010, these two remain the only people to reach this extreme depth. No manned vessel has ever repeated this feat. In 1995, the Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese sent an unmanned submersible to this depth, Kaikō
Kaiko
was a remotely operated underwater vehicle built by the Japan Agency for Marine-Earth Science and Technology for exploration of the deep sea. Kaikō was the second of only three vessels ever to reach the bottom of the Challenger Deep, as of 2010...

, but it was later lost at sea. Most recently, in 2009, a team from the Woods Hole Oceanographic Institution
Woods Hole Oceanographic Institution
The Woods Hole Oceanographic Institution is a private, nonprofit research and higher education facility dedicated to the study of all aspects of marine science and engineering and to the education of marine researchers. Established in 1930, it is the largest independent oceanographic research...

 sent a robotic submarine named Nereus
Nereus (underwater vehicle)
Nereus is a hybrid autonomous underwater vehicle built by the Woods Hole Oceanographic Institution . Constructed as a research vehicle to operate at depths of up to , it was designed to explore Challenger Deep, the deepest surveyed point in the global ocean...

to the bottom of the trench.

The onboard systems indicated a depth of 37,800 ft (11,521 m) but this was later corrected to 35,813 ft (10,916 m) by taking into account variations arising from salinity and temperature. Later and more accurate measurements made in 1995 have found the Challenger Deep to be shallower at 35,798 ft (10,911 m).

The bathyscaphe was equipped with a powerful light, which illuminated a small flounder-like fish, putting to rest the question of whether or not there was life at such a depth in the complete absence of light. The crew of the Trieste noted that the floor consisted of diatom
Diatom
Diatoms are a major group of algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons , fans , zigzags , or stellate colonies . Diatoms are producers within the food chain...

aceous ooze and reported observing "some type of flatfish, resembling a sole
Sole (fish)
Sole is a group of flatfish belonging to several families. Generally speaking, they are members of the family Soleidae, but, outside Europe, the name sole is also applied to various other similar flatfish, especially other members of the sole suborder Soleoidei as well as members of the flounder...

, about 1 foot long and 6 inches across" lying on the seabed. The report has since been questioned, with suggestions that it may have been a sea cucumber.

See also

  • 1948 FNRS-2
    FNRS-2
    The FNRS-2 was the first bathyscaphe. It was created by Auguste Piccard. Work started in 1937 but was interrupted by World War II. The deep-diving submarine was finished in 1948. The bathyscaphe was named after the Belgian Fonds National de la Recherche Scientifique , the funding organization for...

  • 1953 Trieste
    Bathyscaphe Trieste
    The Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe with a crew of two, which reached a record maximum depth of about , in the deepest known part of the Earth's oceans, the Challenger Deep, in the Mariana Trench near Guam, on January 23, 1960, crewed by Jacques Piccard ...

  • 1964 Trieste II
    Bathyscaphe Trieste II
    Trieste II ' was the successor to Trieste — the United States Navy's first bathyscaphe purchased from its Swiss designers. The original Trieste design was heavily modified by the Naval Electronics Laboratory in San Diego, California and built at the Mare Island Naval Shipyard...

  • 1966 Alvin
    DSV Alvin
    Alvin is a manned deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution in Woods Hole, Massachusetts. The vehicle was built by General Mills' Electronics Group in the same factory used to manufacture breakfast cereal-producing...

  • 1964 Aluminaut
    Aluminaut
    Aluminaut was built in 1964 and was the world's first aluminum submarine. The 80-ton, 51 foot manned deep-ocean research submersible was built by Reynolds Metals Company, which was seeking to advertise the utility of aluminum...

  • 1987 MIR
    MIR (submersible)
    Mir is a self-propelled Deep Submergence Vehicle. The project was initially developed by the USSR Academy of Sciences along with Design Bureau Lazurith. Later two vehicles were ordered from Finland...

  • DSV Shinkai
    DSV Shinkai
    The Shinkai 6500 is a manned research submersible that can dive up to a depth of 6,500 m. It was completed in 1990 and has the greatest depth range of any manned research vehicle in the world. The only manned expedition to have gone deeper was the dive of the Trieste bathyscaphe in 1960. However,...

  • Sea Pole class bathyscaphe
    Sea Pole class bathyscaphe
    The Sea Pole class bathyscaphe is a class of little known bathyscaphe of the People's Republic of China , capable of diving up to 7,000 metres, covering 99.8% of the oceanic floor of the world...

  • Dragon class bathyscaphe
  • Harmony class bathyscaphe
  • Timeline of underwater technology
    Timeline of underwater technology
    This is a timeline of underwater technology.The entries marked ## are about decompression tables.-Pre-industrial:* Several centuries BC: This is a timeline of underwater technology.The entries marked ## are about decompression tables.-Pre-industrial:* Several centuries BC: This is a timeline of...

  • Submersible
    Submersible
    A submersible is a small vehicle designed to operate underwater. The term submersible is often used to differentiate from other underwater vehicles known as submarines, in that a submarine is a fully autonomous craft, capable of renewing its own power and breathing air, whereas a submersible is...

  • Diving chamber
    Diving chamber
    A diving chamber has two main functions:* as a simpler form of submersible vessel to take divers underwater and to provide a temporary base and retrieval system in the depths;...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK