Diving

diving

Sport of plunging into water, usually headfirst and often following the execution of one or more acrobatic maneuvers. It emerged as a competitive sport in the late 19th century and became part of the Olympic Games in 1904. Dives are performed from a firm platform 5 or 10 m (16.4 or 32.8 ft) above the water, or from a springboard 1 or 3 m (3.3 or 9.8 ft) above the water. In Olympic contests, only the 10-m platform and 3-m springboard are used. Contestants are required to do certain dives, as well as dives of their own choice, each rated according to its degree of difficulty. Judges score each dive, and the total score is multiplied by the degree of difficulty.

---

Diving 

the sector of productive activity involving submerging people underwater in special gear to perform various jobs. Diving involves diving technique (including labor safety in underwater jobs) and methods of diving work. The physiology and occupational hygiene of diving labor are investigated to determine the effect of the surrounding medium on the diver. Diving causes profound changes in the human organism through the effects of increased pressure, low temperatures, and other factors. On this basis the conditions of diving work and methods of preventing and treating occupational diving diseases are developed.

Man began to conquer the underwater world in very ancient times. The first divers went underwater to depths of 20-30 meters without any gear, holding their breath for up to two minutes. Later, divers began to use breathing tubes made of reed, leather bags with an air supply, the diving bell (in which the human being would breathe the air formed in the upper part of the bell—the “air cushion”), and—with the invention of the air pump at the end of the 18th century—diving equipment, the basic component of which is the diving suit.

The diving school that opened at Kronstadt in 1882 played a large part in the development of diving in Russia. It trained divers for the navy, made and improved diving equipment, and published rules of diving.

Diving has become widespread in the years of Soviet power. In June 1919 a decree was published, signed by V. I. Lenin, which nationalized the diving enterprises and their property and put them under the control of the Main River Transportation Administration of the Supreme Council on the National Economy. In 1923 in the Black Sea area the Special Purpose Underwater Work Expedition (EPRON) was formed. It subsequently consolidated all diving and ship-raising work in the USSR. At the start of the Great Patriotic War, EPRON was included in the composition of the Navy of the USSR and reorganized into the Naval Emergency Rescue Service. During the war years its divers successfully performed combat assignments, raised and repaired ships, and carried out other tasks. In the postwar period, the reconstruction and development of the USSR water system called for the training of a large number of qualified diving specialists and further improvement in diving.

Current diving gear includes the apparatus, technical devices, and equipment used to perform the various diving jobs. The gear that ensures human survival under the water is called the diving apparatus, which is further subdivided by the means of supplying gas mixtures for breathing into autonomous (self-contained) diving apparatus and nonautonomous apparatus; by the breathing method into ventilated apparatus with open, semiclosed, and closed breathing arrangements; and by the composition of gas mixtures for breathing into air, oxygen, nitrogen-oxygen, helium-oxygen, and so on. The part of the diving apparatus that forms the gas- and water-resistant shell isolating the diver from the external environment is called the diving suit.

The most common type of diving apparatus in the USSR is the ventilated three-bolt apparatus, in which the diver breathes compressed air fed from the surface by a hose. The depth of submersion in it is limited to 60 m (at a greater depth so-called nitrogen narcosis may occur). Underwater jobs at shallow depths (up to 20 m) are usually done in the 12-bolt ventilated apparatus. For submerging to depths up to 100 m the air-oxygen apparatus is used (supplying an air-helium mixture), while for more than 100 m the helium-oxygen apparatus (supplying air-helium and helium-oxygen mixtures) is used, which permits submersion to depths of 300 m and more.

At the start of the 1930’s in the USSR and abroad, a diving apparatus came into use with a self-contained oxygen breathing device, and in the 1940’s the aqualung appeared: a diving apparatus with an air tank, used for both simple diving jobs and for underwater sport.

Diving equipment supports the diver in his descent, his work underwater, and his rise to the surface. This equipment includes diving compressors and pumps; devices to prepare and feed gas mixtures to the divers for breathing; lowering and lifting devices; means of signaling, communications, and warning; hydrolocators; diving tools (manual, pneumatic, and explosive); and decompression chambers. Ladders, chairs, and descending lines are used to lower the diver for work in shallow areas; during deep-water work such special lowering-raising devices are used as a diving bell with a platform, a chair, and a winch.

Diving jobs are divided, according to their purpose, into emergency and rescue, ship, ship raising, ship repair, and underwater technical (the construction and repair of hydrotechnical structures, the laying and repair of underwater pipelines and cables, and so on). During the 1960’s, a special method enabling humans to spend extended times underwater in so-called underwater residential laboratories was developed to increase the efficiency of diving labor. This method makes it possible to eliminate the time spent unproductively for decompression when the diver is rising to the surface from his daily work cycle. Diving labor is used extensively in foreign countries, where a great deal of attention is devoted to deep-water submersion involving the breathing of artificial gas mixtures. Diving has been significantly developed in the United States, France, Great Britain, and West Germany.

The profession of diver demands special training. Divers are divided into three classes by qualifications. The highest qualification is diving specialist (vodolaznyi spetsialist). The work of a diver is categorized as heavy labor. There are diving rules that strictly regulate diving labor in order to avoid accident and illnesses (such as caisson disease, pressure damage to the lungs, and nitrogen narcosis) specific to divers.

REFERENCES

Orbeli, R. A. Issledovaniia i izyskaniia [Materialy k istorii podvodnogo truda s drevneishikh vremen do nashikh dnei]. Moscow-Leningrad, 1947.
Diomidov, M. N., and A. N. Dmitriev. Pokorenie glubin, 2nd ed. Leningrad, 1964.
Edinye pravila okhrany truda na vodolaznykh rabotakh. Moscow, 1965.
Maksimenko, V. P., A. S. Nekhoroshev, and V. D. Surovikin. Vodolaznoe delo. Moscow, 1971.

V. P. MAKSIMENKO

---

Diving 

the underwater swimming of animals that have pulmonary or tracheal respiration. Vertebrates adapted to diving include such mammals as pinnipeds, whales, beavers, muskrats, nutrias, otters, and sea otters. Birds that dive include anatids, loons, penguins, murres, and puffins. Among diving reptiles are crocodilians, many turtles, and snakes. Invertebrate divers include a number of beetles, such as the water scavenger beetles, the European diving beetles, water beetles, and the back swimmers.

Animals usually dive in search of food. They can remain underwater longer than humans. Murres and puffins can dive for five or six minutes, muskrats for 12 minutes, beavers for 15 minutes, Greenland and other large whales for 50 to 60 minutes (sperm whales for longer periods), bottlenose whales for two hours, and crocodilians for many hours. Seals, walruses, beavers, and aquatic birds dive to depths no greater than 30–40 m; most whales dive to 100–200 m (the sperm whale and bottlenose whale dive several hundred m).

The capacity for prolonged stays underwater is determined by an animal’s anatomical and physiological features. Among the most important of these is insensitivity of the respiratory center to accumulation of CO2 in the body; this permits prolonged retention of breath and more complete use of the O2 contained in the blood and lungs. Also important are special reflexes that slow cardiac activity and the angiospasm in muscles and other organs during cessation of breathing, thus enabling most of the blood to be directed to the central nervous system, which is especially sensitive to oxygen starvation. High myoglobin content in the muscles is also needed.

REFERENCE

Kreps, E. M. “Osobennosti fiziologii nyriaiushchikh zhivotnykh.” Uspekhi sovremennoi biologii, 1941, vol. 14, issue 3.