IMPORTANT EVENTS IN OCEAN ENGINEERING HISTORY

Medieval Diving Dress  ---  >>

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HELMET (HARD-HAT) DIVING

Although these early diving bells provided some protection and an air supply, they limited the mobility of the diver. In the 17th and 18th centuries, a number of devices (usually made of leather) were developed to provide air to divers and to afford greater mobility. However, most of these devices were not successful, because they relied on long tubes from the surface to provide air to the diver and thus did not deal with the problem of equalizing pressure at depth.

Lethbridge Diving Engine, 1715

The first real step toward the development of a surface-supported diving technique occurred when the French scientist Freminet devised a system in which air was pumped from the surface with a bellows, allowing a constant flow of air to pass through a hose to the diver in the water. This system is considered by many to be the first true helmet-hose diving apparatus. Freminet has been credited with diving in 1774 with this device to a depth of 50 feet (15 meters), where he remained for a period of 1 hour.

The Klingert's diving suit, 1797

The first major breakthrough in surface-support diving systems occurred with Augustus Siebe's invention of the diving dress in 1819. Around the same time, the Deane Brothers, John and Charles, were working on a design for a "smoke apparatus," a suit that would allow firefighters to work in a burning building. They received a patent for this system in 1823, and later modified it to "Deane's Patent Diving Dress," consisting of a protective suit equipped with a separate helmet with ports and hose connections for surface-supplied air. Siebe's diving dress consisted of a waist-length jacket with a metal helmet sealed to the collar. Divers received air under pressure from the surface by force pump; the air subsequently escaped freely at the diver's waist. In 1837, Siebe modified this open dress, which allowed the air to escape, into the closed type of dress. The closed suit retained the attached helmet but, by venting the air via a valve, provided the diver with a full-body air-tight suit. This suit served as the basis for modern hard-hat diving gear. Siebe's diving suit was tested and found to be successful in 1839 when the British started the salvage of the ship Royal George, which had sunk in 1782 to a depth of 65 feet (19.8 meters) (Larson 1959).

1866 Rouquayrol-Densytouze Apparatus

No major developments occurred in hard-hat gear until the 20th century, when mixed breathing gases, in particular helium-oxygen, were developed. The first major open-sea use of helium and oxygen as a breathing mixture occurred in the salvage of the submarine, the USS Squalus, in 1939. The breathing of mixed gases such as helium-oxygen permitted divers to dive to greater depths for longer periods than had been possible with air mixtures. The hard-hat surface-supported diving technique is probably still the most widely used commercial diving method; the use of heliox mixtures and the development of improved decompression tables have extended the diver's capability to work in this diving dress at depth. Although surface-supported diving has several advantages in terms of stability, air supply, and length of work period, a major problem with hard-hat gear is that it severely limits the diver's mobility. This limitation has been overcome in certain dive situations by the development of self-contained underwater breathing apparatus (scuba).

Department of Commerce National Oceanic and Atmospheric Administration Diving for Science and Technology

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Then and Now: Atmospheric Diving Suits

By - USN LT Mike Thornton, Dr. Robert Randall, and Kurt Albaugh, P.E.

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These photographs are from NOAA's photograph and image collection: http://www.photolib.noaa.gov/