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Excerpted from The History of Oilfield Diving: An Industrial Adventure
by Christopher Swann (Oceanaut Press)
by Christopher Swann (Oceanaut Press)
Before World War II the British Admiralty conducted a few experiments with helium in collaboration with Siebe Gorman & Co. Ltd and several of the firm's associates, including Sir Leonard Hill and Captain G.C.C. Damant. In 1941, E.M. Case and J.B.S. Haldane confirmed the research done in the United States. It is likely that all these researchers were in fact working together; but in any event, the efforts were limited by the difficulty of obtaining helium.
After the war, in 1946, the British experimental work resumed at the newly formed Admiralty Experimental Diving Unit in Portsmouth. The object was to push beyond the 300'/91M limit that the Royal Navy had established for air diving, as a result of trials in Loch Fyne on the west coast of Scotland in 1930–1931, where the maximum depth reached was 344'/105M.
Integral to both the prewar and postwar programs were the Deep Diving Canister and Injection System, and the Submersible Decompression Chamber (SDC). Both were designed by Sir Robert H. Davis and built by Siebe Gorman, of which Davis had been managing director since 1904. The canister and injector, worn on the back as a single unit and connected to a modified standard Davis six-bolt helmet, kept the carbon dioxide in the helmet to a minimum; the SDC, which the diver entered at 60'/18M, provided a tolerably comfortable refuge in which to undergo oxygen decompression.
Initial experiments at the Siebe Gorman works and at Portsmouth resulted in the development of techniques for supplying helium-oxygen mixtures to the injector helmet (the lower density of helium necessitated a different injector jet) and for using the Davis SDC with the US Navy helium tables. This led, in 1947, to open-water dives from HMS Deepwater, again in Loch Fyne. The tests showed that the carbon dioxide scrubbing was inadequate—which was presumably why the dives failed to increase the depth limit over air. They also demonstrated that parts of the US Navy helium tables needed to be reworked.
In 1948, after modifications to both equipment and procedures, the Royal Navy's new diving vessel HMS Reclaim proceeded to Loch Fyne. This time the operation was a complete success. Wearing an injector helmet, his gas supplied by a control panel loaned by the US Navy, Petty Officer Wilfred Bollard spent five minutes on the bottom at 540'/165M, with decompression on oxygen in the SDC from 60'/18M. Eight years later, in October 1956, Lieutenant George Wookey, diving from HMS Reclaim, went to 600'/183M feet in a Norwegian fjord.
Wookey's dive revealed the shortcomings of the Davis SDC for very deep dives. Following standard procedure, Wookey entered the SDC at his first decompression stop, after which the bottom hatch was closed and he and his tender were brought on deck. The long decompression with two people cheek by jowl in such a confined space became so uncomfortable, however, that at the 30'/9M stop the SDC was depressurized and Wookey and his tender transferred to a larger chamber to finish their decompression. As he was running across the deck, Wookey complained of the onset of a pain in his shoulder, which prolonged his decompression to almost 12 hours. The experience convinced all concerned that deep diving could not be safely and effectively undertaken without a transfer-under-pressure (TUP) system and, in about 1962, a TUP system designed and built by Siebe Gorman was installed aboard HMS Reclaim.
Britain was not the only country other than the United States to experiment with helium. Before World War II, the United States sold some helium to the Soviet Union—which presumably was not yet extracting its own helium (Russia and Poland both had exploitable sources). In 1940, Russian scientists at the barothermolaboratory of the Military-Medical Academy in Leningrad began tests with helium-oxygen decompression. In June of that year four diving instructors spent ten minutes at 200M/656', decompressing in 122.5 minutes, with a switch to oxygen at 30M/98'. Two further dives, to 190M/623' and 200M/656', followed in November and December.
On the November dive, the researchers noticed that the handwriting of one of the subjects was shaky. On the December dive, his hands were seen to tremble. This was almost certainly the first instance in humans of what would much later become known as the High Pressure Nervous Syndrome (HPNS), a condition brought about by exposure to high pressures, rendered particularly severe by rapid compression with helium. The German blockade of Leningrad in 1941 brought the experiments to a halt; but work resumed in 1944–45 with dives to 200M/656', for 10-, 20- and 30-minute bottom times. In 1946, near Sukhumi in the Black Sea, two divers made a bell dive to 200M/656'.
In 1956, the Russians made a series of dives in the Caspian Sea, starting at 200M/656'and progressing in 20M/66' intervals to 300M/984'. A number of divers took part, using the new Russian GKS-3M helium injector equipment. Four divers—Limbens, Shalaev, Poraghevsky and Kovalevsky—went down to 300M/984'. The time at depth was ten minutes, the partial pressure of oxygen, 1.0 atmosphere.
Decompression, carried out in the bell and in the deck chamber after lock-on, was fast, with the divers switching to 50% air, 50% helium at 100M/328', air at 60M/197' and pure oxygen at 20M/66'. Electrocardiograms recorded during the dives by Vladimir Smolin, a Soviet navy physician, produced a distorted pattern which the scientists, observing muscle rigidity, ascribed to the extreme cold brought on by breathing helium at 300M//984' in 4°C/49F water. It was later found that muscle rigidity is a symptom of HPNS.
In 1954, Smolin and another Soviet navy physician, Nikolai Koval, conducted a chamber dive in which the subjects breathed an air-helium mixture from rebreather bags. The purpose of adding air was to reduce the cost of the gas and offset the heat-robbing properties of helium, as well as to improve voice communication. In 1956, Genrih Zal'tsman formulated the use of 50% air, 50% helium from 61M/200' to 100M/328', and 33% air, 67% helium from 101M/331'to 160M/128'. Straight helium-oxygen was to be used beyond 160M/128'. The experiments were completed too late to be applied to the Caspian dives but, in the autumn of 1956, Zal'tsman ran field trials in Lake Ladoga, near Leningrad. Not until very much later was it discovered, in the West, that nitrogen suppressed HPNS.
The rest of the world seems not to have learned about these dives until well after the collapse of the Soviet Union. As far as Europe and America were concerned, Wookey’s 600'/183M dive was a world record: one that would stand until June 1961 when the Swiss mathematician Hannes Keller went down to 720'/220M in an Alpine lake.
