04 February 2009

Bathyscaphe

The invention: A submersible vessel capable of exploring the deepest trenches of the world’s oceans. The people behind the invention: William Beebe (1877-1962), an American biologist and explorer Auguste Piccard (1884-1962), a Swiss-born Belgian physicist Jacques Piccard (1922- ), a Swiss ocean engineer Early Exploration of the Deep Sea The first human penetration of the deep ocean was made byWilliam Beebe in 1934, when he descended 923 meters into the Atlantic Ocean near Bermuda. His diving chamber was a 1.5-meter steel ball that he named Bathysphere, from the Greek word bathys (deep) and the word sphere, for its shape. He found that a sphere resists pressure in all directions equally and is not easily crushed if it is constructed of thick steel. The bathysphere weighed 2.5 metric tons. It had no buoyancy and was lowered from a surface ship on a single 2.2-centimeter cable; a broken cable would have meant certain death for the bathysphere’s passengers. Numerous deep dives by Beebe and his engineer colleague, Otis Barton, were the first uses of submersibles for science. Through two small viewing ports, they were able to observe and photograph many deep-sea creatures in their natural habitats for the first time. They also made valuable observations on the behavior of light as the submersible descended, noting that the green surface water became pale blue at 100 meters, dark blue at 200 meters, and nearly black at 300 meters. A technique called “contour diving” was particularly dangerous. In this practice, the bathysphere was slowly towed close to the seafloor. On one such dive, the bathysphere narrowly missed crashing into a coral crag, but the explorers learned a great deal about the submarine geology of Bermuda and the biology of a coral-reef community. Beebe wrote several popular and scientific books about his adventures that did much to arouse interest in the ocean. Testing the Bathyscaphe The next important phase in the exploration of the deep ocean was led by the Swiss physicist Auguste Piccard. In 1948, he launched a new type of deep-sea research craft that did not require a cable and that could return to the surface by means of its own buoyancy. He called the craft a bathyscaphe, which is Greek for “deep boat.” Piccard began work on the bathyscaphe in 1937, supported by a grant from the Belgian National Scientific Research Fund. The German occupation of Belgium early in World War II cut the project short, but Piccard continued his work after the war. The finished bathyscaphe was named FNRS 2, for the initials of the Belgian fund that had sponsored the project. The vessel was ready for testing in the fall of 1948. The first bathyscaphe, as well as later versions, consisted of two basic components: first, a heavy steel cabin to accommodate observers, which looked somewhat like an enlarged version of Beebe’s bathysphere; and second, a light container called a float, filled with gasoline, that provided lifting power because it was lighter than water. Enough iron shot was stored in silos to cause the vessel to descend. When this ballast was released, the gasoline in the float gave the bathyscaphe sufficient buoyancy to return to the surface. Piccard’s bathyscaphe had a number of ingenious devices. Jacques- Yves Cousteau, inventor of the Aqualung six years earlier, contributed a mechanical claw that was used to take samples of rocks, sediment, and bottom creatures. A seven-barreled harpoon gun, operated by water pressure, was attached to the sphere to capture specimens of giant squids or other large marine animals for study. The harpoons had electrical-shock heads to stun the “sea monsters,” and if that did not work, the harpoon could give a lethal injection of strychnine poison. Inside the sphere were various instruments for measuring the deep-sea environment, including a Geiger counter for monitoring cosmic rays. The air-purification system could support two people for up to twenty-four hours. The bathyscaphe had a radar mast to broadcast its location as soon as it surfaced. This was essential because there was no way for the crew to open the sphere from the inside.The FNRS 2 was first tested off the Cape Verde Islands with the assistance of the French navy. Although Piccard descended to only 25 meters, the dive demonstrated the potential of the bathyscaphe. On the second dive, the vessel was severely damaged by waves, and further tests were suspended. Aredesigned and rebuilt bathyscaphe, renamed FNRS 3 and operated by the French navy, descended to a depth of 4,049 meters off Dakar, Senegal, on the west coast of Africa in early 1954. In August, 1953, Auguste Piccard, with his son Jacques, launched a greatly improved bathyscaphe, the Trieste, which they named for the Italian city in which it was built. In September of the same year, the Trieste successfully dived to 3,150 meters in the Mediterranean Sea. The Piccards glimpsed, for the first time, animals living on the seafloor at that depth. In 1958, the U.S. Navy purchased the Trieste and transported it to California, where it was equipped with a new cabin designed to enable the vessel to reach the seabed of the great oceanic trenches. Several successful descents were made in the Pacific by Jacques Piccard, and on January 23, 1960, Piccard, accompanied by Lieutenant DonaldWalsh of the U.S. Navy, dived a record 10,916 meters to the bottom of the Mariana Trench near the island of Guam. Impact The oceans have always raised formidable barriers to humanity’s curiosity and understanding. In 1960, two events demonstrated the ability of humans to travel underwater for prolonged periods and to observe the extreme depths of the ocean. The nuclear submarine Triton circumnavigated the world while submerged, and Jacques Piccard and Lieutenant Donald Walsh descended nearly 11 kilometers to the bottom of the ocean’s greatest depression aboard the Trieste. After sinking for four hours and forty-eight minutes, the Trieste landed in the Challenger Deep of the Mariana Trench, the deepest known spot on the ocean floor. The explorers remained on the bottom for only twenty minutes, but they answered one of the biggest questions about the sea: Can animals live in the immense cold and pressure of the deep trenches? Observations of red shrimp and flatfishes proved that the answer was yes. The Trieste played another important role in undersea exploration when, in 1963, it located and photographed the wreckage of the nuclear submarine Thresher. The Thresher had mysteriously disappeared on a test dive off the New England coast, and the Navy had been unable to find a trace of the lost submarine using surface vessels equipped with sonar and remote-control cameras on cables. Only the Trieste could actually search the bottom. On its third dive, the bathyscaphe found a piece of the wreckage, and it eventually photographed a 3,000-meter trail of debris that led to Thresher‘s hull, at a depth of 2.5 kilometers.These exploits showed clearly that scientific submersibles could be used anywhere in the ocean. Piccard’s work thus opened the last geographic frontier on Earth.