Bathyscaphe
The word bathyscaphe or bathyscaphe refers to a special type of deep-sea submarine . The concept of the bathyscaphs was developed by the Swiss researcher Auguste Piccard , from whom the name comes. He used the Greek words bathys ("deep") and skaphos (" ship "). The term is in contrast to the mesoscaph .
Technique of a bathyscaph
The flameproof bathysphere for the crew is on floats attached. Except for the diving ball, there must be no air-filled cavities when diving. Therefore, the float is filled with a liquid that has a lower density than water. Usually gasoline is used for this. Liquids are hardly compressible and therefore retain their volume and thus their static buoyancy at depth . So that the slight compressibility does not cause any deformation of the float, the tanks are designed to be free-flooding. This means that they are equipped with an opening on the underside for flooding.
The immersion ball is accessed via a shaft. This is not pressure-resistant and is therefore flooded during the dive. On the underside of the submarine, grabbers, lamps, cameras and other equipment are attached in the field of view of the crew.
The up and down movement is controlled by ballast .
- The gasoline and the initially air-filled water ballast tanks provide buoyancy: the bathyscaphe floats .
- At the beginning of the dive, the water ballast tanks are flooded: the buoyancy is reduced, the submarine sinks.
- Iron ballast is thrown off to surface: the bathyscaphe rises again.
The controls are therefore similar to a balloon .
A special form of ballast consists of a long, heavy chain. As long as the chain hangs freely in the water, it adds to the total weight of the bathyscaphe. As soon as it hits the ocean floor, the total weight of the bathyscaphe is reduced by the weight of the chain links lying on the ground. The further the bathyscaphe sinks, the lower the effective total weight becomes: the sinking is initially slowed down and finally stopped. This is an important safety element: it automatically prevents it from hitting the seabed. The chain also acts like a drag anchor .
The iron shot ballast is located in ballast silos and is held there by electromagnetically closing slides. When surfacing, the electromagnets are switched off, whereby the slides open automatically or by spring force and the ballast falls down. This fail-safe principle is used for safety: In the event of a power failure or a defect in the system, the bathyscaphe appears automatically. The batteries are under ambient pressure. They must therefore not contain any air-filled cavities.
As a further safety measure, additional ballast can be carried, which is thrown off in emergencies. The float can contain additional tanks that are pumped out on the surface and filled with air to improve swimming behavior on the surface.
The bathyscaphe is a further development of the diving ball on a rope ( bathysphere ): Thanks to the independent buoyancy control and electrically driven screws , it can operate much more independently than a bathysphere. Compared to a submarine , the bathyscaphe's mobility is limited, but it can dive considerably deeper. A military submarine reaches a depth of around 600 meters , the bathyscaphe's Limiting Factor depth record is 10,928 meters.
Due to the poor maneuverability, Bathyscaphe are dependent on support from a mother ship . They are either towed to the target area or carried on board and launched into the water at their destination. The filling with buoyancy fluid and iron ballast usually only takes place on site.
history
The concept of the bathyscaphe was developed by the Swiss physicist Auguste Piccard during the 1930s. Piccard had previously invented a pressure capsule with which he climbed under a balloon up to 15,785 meters in 1931 and on August 18, 1932 with a balloon even advanced to 16,940 meters in the stratosphere . The pressure capsule and the balloon were named after the supporting Belgian society, FNRS-1 after " Fonds National de la Recherche Scientifique ". By applying the principle of the stratospheric balloon to the depths of the ocean, the bathyscaphe , the FNRS-2 , was built, which was built from 1946 and tested in 1948.
In 1953 he dived for the first time with a bathyscaphe, the Trieste , a further development of the predecessor FNRS-2 , off the Mediterranean island of Ponza to a depth of 3150 meters; the submersible withstood a water pressure of up to 420 bar , which is 420 times the air pressure . The French bathyscaphe FNRS-3 set another depth record in February 1954 and reached 4050 m near Dakar , which the Trieste exceeded in the Pacific in 1959. On January 23, 1960, the Trieste finally dived to the record depth of 10,740 or, depending on the measurement, 10,916 meters, valid until 2012 ( Deepsea Challenger ) , at a point at the bottom of the Mariana Trench , the Challenger Deep. Here the deep-sea submersible withstood a pressure of 1170 bar, 1155 times the mean air pressure at sea level.
After these record runs, the bathyscaphs of that time carried out mainly scientific expeditions to explore the sea floor and deeper water layers. In addition, such vehicles were always involved in the search for sunken submarines, for the first time in 1963 when the Trieste investigated the wreck of the American nuclear submarine USS Thresher . The French Archimède was also used in 1968 and 1970 to search for the submarines Eurydice and Minerve (both units of the Daphné class ) that had sunk in the Mediterranean . In 1970 this vehicle even rescued the unmanned wrecked submersible Cyana by using a manipulator to cut off the emergency ballast. By 1980 all bathyscaphs were decommissioned, most recently the Trieste II .
outlook
Compared to the offshore work submersible and research submersibles like Alvin , the pure bathyscaphs are rather immobile and therefore only usable to a limited extent. In addition, their construction is comparatively sensitive and their use is complex. Your advantage lies in the great depth you can reach, the greatest possible. In fact, the accessibility of such depths, which mostly only occur in deep-sea gullies, has proven to be unnecessary for normal scientific operations.
On March 26, 2012, James Cameron reached the bottom of the Challenger Deep in the Mariana Trench alone and as the third person in his boat Deepsea Challenger . Here, the structural features of the bathyscaphe were no longer strictly used, as specialized and compact material was used for the float instead of gasoline.
More recent considerations are aimed at covering the research goals in greater depth in the future with unmanned diving robots ( Remotely Operated Vehicle , ROV) or dynamically diving micro submersibles. The projects have not yet progressed far enough for an evaluation, but still seem possible at least in principle, for example the Japanese diving robot Kaikō reached the bottom of the Mariana Trench, which had previously only been dived by the Trieste . Research goals at shallower depths can be served with the research and work submersibles designed for this depth and built in the meantime. As far as is known, all bathyscaphs built so far have already been decommissioned.
Technologies from research on bathyscaphs found their way into the construction of advanced submersibles on various occasions. For example, all modern deep-sea submarines, starting with the Alvin and the Canadian Pisces series, use spherical pressure hulls, which - as was first used with the Archimède - are located in a streamlined and pressureless hull. Other constructions such as the American submarine Aluminaut , which threw ballast in the form of a lead keel to surface, had no lasting effect.
Well-known bathyscaphs
- FNRS 2
- Built in Belgium in 1946; first bathyscaphe, largely a balloon type with a silo-shaped float and a pressure ball hanging below it. 1948 used for manned tests up to 25 m and unmanned up to 1400 m, badly damaged by rough seas. Funded by the Belgian company FNRS ( Fonds National de la Recherche Scientifique ).
- Trieste
- Built in Italy in 1953; the first manned research boat, originally a research project funded by the Italian city of Trieste . Two depth records: 3,050 m (1953), 10,910 m (1960).
- FNRS 3
- Built in France in 1954, further development with an improved, boat-shaped float. Set the Trieste record in 1954 with a depth of 4050 m . Again funding by FNRS, use of the pressure hull from FNRS-2.
- Archimède
- Built in France in 1961; Research boat with great boat resemblance. Pressure body ball for 3 people integrated in the fuselage. Deep dive in the Kuril Trench near Japan at almost 10,000 m. Can carry nearly 1 tonne of research equipment.
- Trieste II
- Built in 1968; Submersible boat with improved floatation body in torpedo or shuttle form that has been modified several times. Pressure hull ball partially integrated in the fuselage.
With the exception of the FNRS 2 , whose pressure hull was used in the FNRS 3 , all of the bathyscaphe mentioned above have been preserved as museum pieces today. The FNRS 3 is located as a memorial in the Naval Arsenal of Toulon , the Trieste in the United States Navy Museum in Washington, DC , the Archimède in the La cité de la mer museum in Cherbourg and the Trieste II in the Naval Undersea Museum in Keyport , Washington . There is also a test cast of the pressure hull of the Trieste in the Deutsches Museum in Munich .
There were also plans to build bathyscaphs in the Soviet Union . The various designs developed in Leningrad by OKB Giprorybflot with the designations B-5, B-11 and DSB-11 had streamlined floats in the manner of FNRS-3; the diving depths were designed for a maximum of 5,000 to 12,000 m. However, these drafts were not implemented.
See also
literature
- Carol Ruppé, Jan Barstad: International handbook of underwater archeology . Springer, Hamburg 2002, ISBN 0306463458 , pages 671 & 672.
Web links
Hans-Georg Glasemann: The diving ball of Count Piatti dal Pozzo. (pdf, 1.7 MB) In: nonvaleurs.de. October 15, 2013, pp. 22-24 (German, English).
Individual evidence
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↑ Ker Than: James Cameron Completes Record-Breaking Mariana Trench Dive: Solo sub dive is deepest ever. In: National Geographic . March 25, 2012, accessed March 26, 2012 . "Titanic" Director: James Cameron dives to the deepest point of the sea. In: Spiegel Online . March 26, 2012. Retrieved March 26, 2012 .