Man has submerged in the sea since earliest history. Archeologists have classified mother-of-pearl artifacts dating from 4500 B.C.; the Emperor Yu in China is reported to have received oyster pearls as a tribute from tribesmen in 2200 B.C. In Homer’s Iliad, written prior to 700 B.C., there is mention of military diving operations during the Trojan Wars (1194 B.C.). In both the Old and New Testaments of the Bible, and in the Koran and Talmud, pearls are frequently mentioned as a standard of purity and ideal beauty. Indeed, in Rhodes of the 3rd century B.C., diving was regulated by special laws governing divers and the payment of a share of treasure salvaged from the deep. The share increased as the depth increased.
Man’s commercial ventures under the sea are matched by his military adventures. An early use of divers to clear underwater obstacles occurred during the 5th century B.C. Athenian siege of Syracuse. Syracuse had erected palisades in its harbor and had also planted stakes underwater. The Athenians rigged what amounted to a crane ship which lifted the palisades, after which divers were used to saw off the stakes underwater. At about the same time, Xerxes is reported to have hired the diver Scyllis to recover treasure from wrecked ships of the defeated Persians. The historian Herodotus chronicles that the diver Scyllis was rather headstrong. He rebelled when Xerxes tried to detain him on board ship. Scyllis then made good his retirement with a nine-mile swim which was reported to have been underwater. In all fairness to the historian, it must be added that Herodotus interjected his personal disbelief of this breathless feat. Divers’ personalities have not changed through the ages. One will do well to consider with skepticism most sea stories told by divers—whether naval personnel or civilian Ph.Ds.
The warm Mediterranean was an optimum sea for many underwater tactics. Alexander the Great employed divers and swimmers in breaching the boom defense of Tyre in 333 B.C. The history of naval warfare records many similar instances. In 1332, the Turks employed diver/swimmers with augers to pierce the hulls of Greek ships. (And, 600 years later, the Italians emulated them—in World War II.)
The great minds of history were fascinated by undersea technology. Most books on this subject religiously reproduce the famous print of Alexander the Great descending to the sea floor in a transparent diving bell of sorts. Aristotle gave considerable attention to what lay under the sea and how man could live there, dealing both with the means of air supply and with problems of the ears. Leonardo da Vinci made sketches of a military diving apparatus—which could not have worked—and several medieval military writers dealt at length with diving apparatus as a means of mounting underwater expeditions against an enemy.
Most early divers were skin-divers, and it is not at all unusual to this day to find native divers who can “skin” to 100 feet, staying under for three or four minutes. However, Aristotle in the 4th century B.C. writes of the use of a diving apparatus—a kettle or diving bell—by the local sponge divers. The bell, used but rarely today, is classified as a self-contained diving apparatus—albeit tethered to the surface. For at least 22 centuries, until about 1800, the bell was the only practical diving apparatus.
Most of the older references to bell diving do not mention the depth attained, though much attention is paid to duration on the bottom. There was, of course, no appreciation of the depth-pressure problems of diving physiology. Originally, there was no system to replenish the original “load” of air in the bell. By the 17th and 18th centuries there were numerous recorded instances of the use of bells in ship salvage and in what we today call waterfront construction—bridges, caissons, and tunnels. Though the German Franz Kessler in 1616 constructed a barrel-like bell with a harness rig to fit over the diver’s shoulders, and depicted the man walking seaward from the shore, the bell actually had little tactical military merit.
By the late 1600s, bells had become rather refined, with internal platforms and tools. An Englishman, William Phipps, was knighted for his prowess in using one to recover the crown’s sunken treasures. The most significant diving bell was that patented in 1691 by the English astronomer, Edmund Halley. His was a sizable and sophisticated bell. The unique feature was a scheme to replenish the air inside. His scheme called for two lead-lined barrels to be lowered alternately to transport fresh air to the bottom where the fresh air could be vented into the bell. The bell contained a valve in its overhead to vent out the used “hot air.” Halley reported descending to a depth of 60 feet, with four other men in the bell, and remaining there for an hour and a half. His patent also implied that divers could be sent out from the bell, receiving air by means of small flexible hoses. But there is no record that he actually carried out this latter diving stunt.
Halley’s patent signalled the end of bell diving as a self-contained technique. The industrial revolution was getting under way, and it was a small step to substitute a pump for Halley’s barrels. When this happened the bell became a caisson and man could work for long periods underwater. But he still had no mobility except within the caisson. Halley and Kessler, then, had presaged the two essential elements of a mobile diver’s rig which would develop into the “hard hat” rig.
Surface-supplied compressed-air diving was about to be born.
Before going into the development of helmet diving which, by 1800, became—and, until ten years ago, remained—the prevalent diving technique, one ingenious scheme, dated 1680, bears mention. Following up on Leonardo da Vinci’s interest in the military applications of underwater breathing, Italian physicist Giovanni A. Borelli devised an ingenious, honest-to-goodness scuba for underwater swimmers. The apparatus was based on a theory that the diver’s hot, exhaled breath could be rejuvenated by cooling and condensation. Borelli’s apparatus envisioned a pair of breathing tubes, one tube to carry exhaled breath to a condenser, and thence to a large copper or tin helmet-like reservoir, and another tube to act as an inhalation tube. The helmet contained a face piece rather like that in our present hard hat. While the apparatus certainly could not have worked, Borelli was on the right track. He even seems to have fore-told the problem of oxygen depletion or anoxia, for he specified that the diver should surface every 30 minutes and, by manipulating valves provided in the tubes, purge the reservoir and replenish the air supply.
Two other facets of Borelli’s apparatus bear note. He was the first to provide the diver with foot-fins and to stage underwater man as a swimmer, rather than a walker. This concept lay dormant until about 1930, a period of 250 years. The other unique feature of Borelli’s rig was a buoyancy compensating device by which his diver could surface himself at 30-minute intervals. By cranking a piston in and out, the diver supposedly could adjust his buoyancy. Adjusting for increased buoyancy—as a scuba diver expends his gas—is still a problem today.
Others during the 18th and 19th centuries followed Borelli’s scheme, basing their scuba on the same theory of air regeneration. It was not until approximately 1835, when the chemistry of co2 absorption was understood and the mine safety engineers and anesthesiologists had developed their breathing equipment, that the design of closed and semi-closed circuit scuba took up what Borelli had started.
Returning to the hard hat divers: by 1770, the stage was set for surface-supplied, compressed air diving. Elementary air compressors were available. In 1774, in Le Havre, the Frenchman, Sieur Freminet demonstrated a helmet-hose diving apparatus in which air was supplied by a large bellows system on the surface. The dive, a record at the time, was to a depth of 50 feet for one hour.
There followed numerous designs of surface-supplied apparatus. Some even supplied a bellows strapped to, and hand-pumped by, the diver. One rather ridiculous rig had a pair of bellows on the diver’s back, much like two scuba bottles. The bellows were operated by a single throw crank shaft. The piston rod from the crank shaft was attached to a metal head band on the diver and he was supposed to pump his own air by nodding his head as he walked along the bottom. This apparently did not gain wide recognition, divers preferring to use their heads for other things.
Major ship disasters and resulting search or salvage work generally have stimulated major improvements in the techniques of deep submergence. In 1782, hms Royal George, a three-decked, ship-of-the-line battleship and flagship capsized and sank at Spithead, England. She was not actually salvaged until 1842, but in the intervening years there was constant effort both to raise her and to salve her guns and valuables. The Royal George was to diving and salvage in the early 1800s what the Normandie was to U. S. Navy diving and salvage in World War II.
It was for the Royal George salvage operation that the Englishman, Augustus Siebe, later the founder of the famous British firm, Siebe-Gorman and Company, developed and perfected his diving helmet. This was originally a helmet without dress; that is, an “open,” shallow water helmet rig. Also, at this time the familiar “hurdy-gurdy” divers hand pumps were put into service and the hoses from surface to diver were improved. By 1837, still working on the Royal George, Siebe modified his rig to the now familiar “closed dress” type, wherein the diver was fully clothed in a canvas dress, to which was bolted the helmet and breast plate. This same apparatus, with improvements in its details, is still used today.
Thus, from 1837 forward, the progress of diving became dependent on two factors—one engineering, and the other scientific—the improvement of air compressors and the development of an understanding of the hyperbaric, or diving, physiology. Air compressors developed quickly in pace with the industrial revolution. The physiology, however, made little progress until the work of French physiologist Paul Bert who, in 1878, published work which began to shed light on what the physiologists call “decompression sickness” and what divers call the “bends” and tunnel workers call “caisson disease.”
It was after Bert’s work that divers and tunnel workers began to use the procedure of recompression to relieve the bends. Before that time divers either limited their depth and bottom time, or withstood the consequences. It is significant that the first recompression chamber for the treatment of bends was installed to support the sand hogs working on the first Hudson River Tube in New York in 1893.
About this same time other scientists, among them John Scott Haldane, M.D., began working on the problems of diving physiology. There was great interest in going deeper and working longer. Waterfront conduction was under way everywhere, and ship salvage work was booming as a consequence of increased shipping and the several wars between 1880 and the early 1900s. It was in this period that Haldane developed his theory of tissue saturation which led to step-wise or stage decompression diving. Prior to this, decompression had meant a continuous but regulated slow rate of ascent. Stage decompression led to tables which specified “stops” en route to the surface.
Based on Haldane’s work, the British Admiralty in 1906 appointed a Deep Diving Committee to investigate the whole field of diving. The committee, with Haldane as a member, sponsored and supervised an extensive series of dives to test the new theory and the “Decompression Tables.” The outcome was the official Royal Navy adoption of this system of diving and the administrative establishment of a 34-fathom depth limit to which divers could work.
At this point it will be well to mention Warrant Gunner George Stillson, U. S. Navy, who as much as anyone was the father of diving in our Navy. At the turn of the century, being a warrant gunner, he was de facto a diver. By chance, he had had occasion in the Period 1900–1910 to be associated with several complicated ship salvage operations. He had more or less become the Navy’s chief diver—at least, its most outspoken one.
At the turn of the 20th century, there had been very little attention paid to diving in the U. S. Navy. Equipment was not standardized and, to say the least, operating procedures were very loose. The U. S. Navy’s Manual for Divers, dated 1905, makes almost humorous reading. Chapter I, entitled “Requirements for Divers,” reads as follows:
Before men are detailed for diving, they should be examined as to their fitness by a medical officer. As this is sometimes impracticable, the following list of requirements and of physical defects which should cause the rejection of men having them is given for the benefit of those who may be called upon to select candidates for this employment. Divers are: “To be cool-headed, calm and of a phlegmatic temperament . . . To be in good health, have a strong constitution, and the action of the lungs to be normal . . . Not to be short-necked, full-blooded, or with a tendency to nosebleed . . . Not to be very pale, nor have lips more blue than red, nor be subject to cold hands and feet . . . Not to perspire freely . . . Not to be hard drinkers, nor have suffered frequently with venereal disease, or have had sunstroke or rheumatism . . . Not to have been subject to palpitation of the heart or fainting spells . . . Not at any time to have spat or coughed up blood.” Men who have long trunks with well developed chests and loins generally make good divers.
Stillson, in December 1912, wrote a letter stating that “our methods of diving are obsolete and our diving apparatus capable of great improvement.” At least these watered-down words are the way in which the official Bureau of Construction and Repair (forerunner of BuShips) report put.it. As is so often the case, the chief complainant was given the chore of squaring away the problem. Stillson was ordered to the New York Navy Yard where, during 1913 and 1914, he and Passed Assistant Surgeon George French set about to improve U. S. Navy diving. Test dives were made in a pressure tank. Later, in Long Island Sound, deep sea tests were conducted from the destroyer uss Walke (dd-34). Today we would call their work “state of the art” investigation. Stillson and French procured at least one copy of every U. S. and foreign diving apparatus. They were also aware of the work of Haldane and the Admiralty’s 1906 Deep Diving Committee. Their report, dated 10 December 1914 and published by the Bureau of C and R in 1915, was a milestone in the U. S. Navy’s Deep Submergence Program. Haldane’s decompression tables were adopted; improved standardized diving equipment and recompression chambers were specified; and a comprehensive Diving Manual was eventually prepared. Stillson and French had assembled a team of four Navy divers for this experimental work and they had pushed diving from the 1907 British record of 211 feet to a new record of 274 feet in November 1914. This was no small feat.
It was doubly fortuitous that Stillson’s work had been done, for on 25 March 1915, the first major U. S. Navy submarine disaster occurred when the F-4 went down off Honolulu. Government and public reaction to the F-4’s loss was almost identical to that after the Thresher went down. Experts were dispatched to Hawaii at once. Stillson, French, and their four divers departed New York by train on 2 April. They arrived in San Francisco, boarded the uss Maryland, and sailed on 6 April, arriving in Hawaii on 12 April. On 14 April, on the first dive, they reached the F-4’s deck at 288 feet, another new record. Later dives to the bottom set yet another record—306 feet—before the F-4 was finally raised.
Subsequent to the F-4 salvage operation, Stillson and crew returned to the old Torpedo Station at Newport, Rhode Island, and expanded the local diving course into what amounted to the Navy’s first diving school. In World War I, the school was disbanded when most of its personnel were sent to France to participate in salvage operations. Informal diver training continued to be conducted after the war in Newport, but there was no actual school. The Bureau of Construction and Repair did, however, adopt most of Stillson and French’s 1915 recommendations and, in 1924, published the first real U. S. Navy Diving Manual. This Manual authorized diving—on compressed air, of course—to only 250 feet, even though the F-4 dives were to 300 feet or better. This difference in footage was a recognition of the nitrogen narcosis problem at this depth—though not at the time defined as such.
It was in the same year, 1924, that the Bureau of C and R and the Bureau of Mines began experimenting with the use of helium-oxygen mixtures for deep diving and caisson work. The work was originally undertaken at the Mines Experimental Station in Pittsburgh, using animals for subjects. By 1927, this work had progressed sufficiently to allow use of human subjects and the U. S. Navy Experimental Diving Unit was established. The edu was initially located at the Washington Navy Yard, in a shed alongside David Taylor’s original Model Basin. By 1926, it became evident that an expanded Navy training program for deep divers was needed, and so the Deep Sea Divers School was established, adjacent to the Experimental Diving Unit. By 1935, permanent quarters, with what at the time was the world’s most advanced hyperbaric test facility, were built next door and both activities moved. Now somewhat expanded, this facility remains today one of the world’s principal diving research and training activities.
The Experimental Diving Unit embarked on an exhaustive program of test dives, equipment redesign, and general research in the field of diving physiology. (It should be added that the pressure chambers at edu were at the outset fitted as altitude chambers and some of the Navy’s original work in aviation medicine was performed there.) The development of the helium-oxygen diving equipment and decompression tables progressed steadily. In May 1939, when the submarine Squalus sank in 240 feet off Portsmouth, New Hampshire, this new system of diving was ready to use in the field.
The Squalus rescue and salvage operation involved a total of 640 dives. While all diving during the rescue phase was on air, most of the deep diving during the salvage phase employed helium-oxygen. The new technique was proven beyond any doubt.
Of the total of 640 dives, 302 were in depths exceeding 200 feet. In the entire operation there was not a single death or serious injury from diving.
Helium-oxygen, which is a mixed-gas, surface-supplied system of diving, quickly became standard on Submarine Rescue Ships (asrs). By 1943, when the next edition of the Diving Manual was published, test dives had been completed and the decompression tables were extended to 410 feet. The Diving Manual was revised again in 1952, at which time the tables remained at 410 feet, and again in 1956–59, when the maximum tables retreated to 380 feet. Present tests at edu are pointed towards mixed-gas diving to 600–1,000 feet.
Routine diving below 250 feet was the exclusive province of the U. S. Navy in pre-World War II years, primarily due to our monopoly of helium. However, the British continued to be active. In 1930, the Admiralty had convened a second Deep Diving Committee which sponsored further research towards new air decompression tables for as deep as 320 feet. In 1946, an Admiralty Experimental Diving Unit was established, and in 1956 while conducting open sea test dives on Helium, a Royal Navy diver reached 600 feet on a “bounce” dive. He was badly “bent” however, and so, for whatever it was worth, the U. S. Navy still claimed to hold the record for operational open sea dives: 500 feet set by gm1 Pete Prickett in 1950 off the Galapagos Islands. More recently, the British successfully completed a new series of open sea helium tests. In 1963, they reached 450 feet, using this mixed-gas system.
The deep dives of the Swiss engineer, Hannes Keller, have also been on mixed gas but of an undisclosed composition. Keller’s daring dive off Santa Catalina in 1962, under the sponsorship of onr, could certainly be called neither operational nor successful. While he did reach 1,000 feet, his companion was killed, and Keller barely escaped death.
Returning to submarine rescue and salvage, there were two other submarine losses in the 1920s which are landmarks in the history of Navy deep submergence. In September 1925, the S-51, operating on the surface east of Block Island was rammed and sank in 182 feet of water. Four men on the bridge were thrown clear and six others, of whom only three survived, got out through the conning tower hatch as the ship went down. All the rest were trapped. There was no means of rescuing them or for them to escape. The subsequent salvage operation was more or less routine, following the F-4 pattern, but public reaction to the loss of life was intense.
Then on 27 December 1927, the submarine S-4, surfacing off Provincetown, was rammed and sank in only 102 feet of water. By this time a Submarine Rescue and Salvage Ship had been fitted out. The uss Falcon was quickly on the scene. Divers were soon down and by tapping on the hull were able to communicate with men alive, but trapped, inside. There was as yet no rescue or escape system. The only chance of saving the men was for divers to attach air hoses and “blow” the submarine to the surface. However, after several days of diving in worsening weather, the whole operation was terminated by the Officer-in-Charge—Captain Ernest J. King. All hands were lost.
The rescue system in use in the U. S. Navy at the time was wholly dependent on being able to raise the entire submarine by means of blowing through external salvage air fittings after divers had attached hoses and otherwise corrected the problem which caused the boat to sink. Actually, this was rescue-by-salvage and not a particularly rapid-action technique.
The S-4 disaster was given a phenomenal play by the newspapers. The timing of the loss during the holiday season, the nearness to the big city newspapers in Boston and New York, and the general mass psychology of the time, all coupled with the drama of divers tapping out Morse Code to trapped crew members inside the boat. Every action, splashed on front pages from coast to coast, caused a tremendous public reaction. While the boat itself was routinely salvaged the following spring, there remained an urgent requirement to provide better submarine escape, rescue, and salvage systems. In June 1928, the President directed the Secretary of the Navy to take corrective action. He appointed a Board to review the thousands of proposals which were being received from industry and the public at large concerning salvage and rescue. The Board was to recommend means of achieving the desired end. Also, the material Bureaus were put to work on the problem. The outcome of these efforts, and nearly 5,000 proposals reviewed by the Board, was the McCann Submarine Rescue Chamber and the Submarine Escape Apparatus, commonly called the Momsen Lung.
Space does not permit the tracing of the development of these two items in detail. Both of them, however, stemmed from earlier efforts in European navies. The McCann Chamber is still in use today and is carried by all asrs. It is really a miniature, non-propelled submarine, which acts as an elevator between the surface and the stricken submarine. It was this rescue device which was used to save 33 men from the control room and forward spaces of the Squalus. The present chamber is theoretically usable to an 850-foot depth, but the system of rescue could be designed for much greater depths, provided the asr could be moored or otherwise positioned directly over the submarine.
Submarine escape devices, as distinct from rescue devices, are really a type of specialized diving equipment. Escape devices have generally been conceived as self-contained diving apparatus, but have not had a marked influence on pushing the limit of man’s deep submergence. The British and German navies gave considerable attention to the subject as early as 1900, and Gunner Stillson’s work in 1914 involved the evaluation of several foreign devices. Stillson’s report, however, did not devote much attention to the subject, other than recommending that all submarine crew members should be trained to dive. The first widely accepted standard U. S. Navy submarine escape device, then, was the famous Momsen Lung, developed during the mid-1920s and accepted for service in 1929. The Momsen Lung was basically a short duration, closed circuit, oxygen scuba, to be donned by the escapee just before entering the submarine’s lock-out chamber. The original device was tested from 206 feet and it was considered usable to 300 feet. Both the British and the German submarines of World Wars I and II had comparable escape lungs.
Post-World War II studies of actual submarine escape incidents showed, interestingly, that the preponderance of successful escapes were performed either without the lungs or with the apparatus inoperative. There was even some suspicion that the lungs, particularly those using pure oxygen, other than being a psychological advantage, were actually a physiological hazard. It appeared that free ascent was a safer escape technique. In 1946, the U. S. Navy’s Escape Training Tanks at New London and Pearl Harbor began to train in the free ascent technique, and by 1956 the Momsen Lung was retired from service and the British system of free, buoyant-assisted ascent was adopted as standard.
All submarine crew members are now trained in the buoyant ascent escape technique. Training escapes from 50 feet are mandatory; ascents from 100 feet are optional. The first open sea buoyant ascents from 300 feet were made in 1960. In 1962, open sea ascents from 314 feet were made by Lieutenant Harris E. Steinke and Commander Walter F. Mazzone, using the new hooded life jacket for buoyant assist. These tests had been preceded by test chamber ascents from 450 feet. Since this free ascent escape technique uses no breathing device, it could properly be listed as a skin diving technique, albeit, skin diving in reverse. In 1964, the hooded life jacket which was developed by Lieutenant Steinke was adopted as the standard apparatus for submarine escape. The “Steinke Hood” is basically an escape aid. To the original inflatable, vest-type submarine life jacket has been added an over-the-head hood with transparent material in front of the face. As the escapee rises, his own exhaled air, as well as the gas escaping from the life jacket, is trapped in the hood, keeping the head and face “dry.” This is a tremendous psychological advantage of the device, and, it might be argued, makes it essentially a diving bell in reverse.
Submarines must be engineered to suit these escape, rescue, and salvage systems. To use the Steinke Hood or any other escape device, as well as the McCann rescue chamber or yet-to-be developed rescue submersibles, escape vestibules and mating hatches are required. Note in passing that these features of the boat do double duty as means of entrance and exit for underwater warriors: udt, seal and other clandestine operators. Submarines are also still fitted with external salvage air fittings to permit dewatering the hull from the surface if sunk in depths which can be reached by divers. In the early days, submarine boats were also fitted with external padeyes for connecting lifting chains but this feature has long been dropped. The latter two features, while useful in salvage work, were never proven to be effective for rescue.
The subject of submarine escape, rescue, and salvage is at the core of the current Deep Submergence Special Project. It is interesting to note the very great similarity on the one hand between the investigations and postdisaster developmental efforts which followed earlier submarine disasters such as F-4, S-51, S-4, and finally the Squalus, and on the other hand, the post-Thresher Deep Submergence Systems Review Group (dssrg) and the follow-on dssp effort of today. These five losses are milestones in the history of man’s deep submergence. These have not, however, been the only submarine losses or near-misses. Admiral Charles A. Lockwood in his book on submarine rescue and salvage, Hell at 50 Fathoms, lists a total of 150 serious “submarine accidents,” exclusive of combat losses in World Wars I and II. This total covers submarines of all navies, starting with the loss, in 1864, of the Confederate States Ship Hunley, down to the fire and near-loss of the Sargo in Pearl Harbor in 1960. Of this total, 45, including the Hunley, were U. S. submarines.
Add to this the Thresher.
One further excursion into history is needed to fill out the history of deep submergence, and lay the background of scuba diving and swimming as we know them today. It is generally conceded that Jacques-Yves Cousteau and Emile Gagnan, in 1942, made the principal breakthrough with their “Aqua-Lung” demand breather. Their device was an open circuit, air scuba and their interest was chiefly recreational. The Italians on the other hand have been the major exponents of military scuba swimming, and consequently they concentrated on a closed circuit rebreathing device. Both of these techniques—open circuit, and closed circuit scuba—were preceded by many earlier devices, developed for the two-fold purpose of giving the diver, and later the swimmer, more mobility underwater by removing his tether to the surface and of providing him with a breathing system unhampered by problems of inadequate compressors and hoses. Reliable compressors with adequate volumetric output, yet small enough for use in a diving boat, were not available until well into this century; reliable, flexible diving hoses were not available until about 1900. The development of practical scuba diving had to await such auxiliary equipment.
An early scuba diving rig was developed and tested in 1835 by a New Yorker named Charles Condert. The apparatus was basically a flexible diving dress and helmet with a U-shaped, closed pipe reservoir at the waist, which acted like a present-day scuba cylinder. The reservoir was pumped up with air prior to the dive. The breathing cycle was free-flow, open circuit. Consequently the device had a short duration. Condert described the apparatus in an 1835 issue of the Journal of the Franklin Institute. The paper was widely reprinted in Europe and is believed to have immediately influenced diving equipment design. This was the first really successful compressed air scuba, even though Condert soon met his death on a shallow dive in the East River.
In 1865, a French mining engineer named Rouquayrol and a French Naval Lieutenant, Denayrouse, developed a unique diving apparatus which had a profound influence on scuba, even though basically surface supplied. This apparatus carried a double-chambered air reservoir on the diver’s back, supplied by hose from the surface. The unique feature was an automatic demand valve which allowed the diver to get a really full breath from the reservoir, something that the low capacity compressors of the time had never before permitted. This was the ancestor of the Cousteau-Gagnan device and all present-day, open-circuit, demand scuba. Actually it was the technique we presently call “Hooka” or surface-supplied demand breathing. This Rouquayrol-Denayrouse device was used by most of the European navies until nearly the end of the 19th century. The French Navy authorized its use to 66 feet; and the Austro-Hungarian Navy authorized its use to 115 feet. Another significant feature of this apparatus was the manufacturer’s instructions that it could be used without helmet and suit in shallow depths to 33 feet. It was thus the first designed “shallow water rig.” The Rouquayrol-Denayrouse apparatus was undoubtedly the basis for Jules Verne’s “10-hour,” self-contained suits with which his divers were outfitted while outside the Nautilus in Twenty Thousand Leagues Under the Sea.
The closing years of the 19th century saw several closed-circuit oxygen scuba diving rigs developed. They employed compressed oxygen and co2 absorbent canisters. The British firm of Siebe-Gorman claims to have marketed the first practical closed-circuit unit in 1878. This was the Fleuss-Davis apparatus. It was widely used for diving to 66 feet and, in modified form, is today the British Navy’s cdba—Clearance Divers Breathing Apparatus. This same Fleuss-Davis apparatus was miniaturized and used as a submarine escape device. Interestingly enough, the American, Simon Lake, patented a similar closed-circuit-scuba in 1881.
There were several other closed-circuit oxygen scuba developed along the lines of the Fleuss-Davis. Some of these units were quite light and simple, particularly those which were intended as submarine escape devices. The Momsen Lung was of this family. In Italy, the Perelli single-hose oxygen scuba became the standard for attack swimmers during World War II. In Germany, the Draeger/Lieutenant Lund model closed-circuit oxygen scuba gained wide acceptance. Both the Perelli and Draeger rigs, as well as the British cdba, have been used at one time or another by the U. S. Navy udt and eod, and it was from them that the design of the present standard U. S. Navy closed-circuit scuba—referred to as the “Emerson rig”—evolved.
Another interesting oxygen scuba, and one which has yet to be fully exploited, was developed, in 1904, by Siebe-Gorman. This was based on the use of the compound “oxylite.” Oxylite is a powder of potassium and sodium peroxide. By dripping water into the powder, pure oxygen is generated. Too much water causes a violent reaction and an extremely caustic solution. The apparatus obviously can be very dangerous. Never widely used, it was this type equipment which was worn by the diver-actors in Hollywood’s 1915 version of Twenty Thousand Leagues Under the Sea.
At about this same time, mixed-gas diving was introduced. In 1912, a German firm brought out an oxygen-nitrogen, mixed-gas, self-contained, helmet-suit apparatus. The instructions called for different gas mixtures in order to reduce the toxic effects of ordinary air: one for diving to 100 feet and another for 200 feet. This was the first mixed-gas scuba and the ancestor of the U. S. Navy’s helium/oxygen diving system. It apparently did not attain wide recognition. Though Stillson’s diving tests in 1913–14 were intended to evaluate all U. S. and foreign commercial diving equipment and several Siebe-Gorman (British) and Draeger (German) air rigs were tested, this mixed-gas unit was not included.
There is no other record of any work in mixed-gas diving—scuba or otherwise—prior to the joint Navy/Bureau of Mines efforts in 1924, which work was widely reported. The next mixed-gas scuba came in 1935 when a group of U. S. diver-scientists developed a helium-oxygen apparatus, with an absorbent canister. They planned to photograph and assist in the salving of the Lusitania which was sunk in 312 feet of water. Though the salvage expedition fell through, the diving equipment was fully operational, and in 1937 one of its designers made a record dive to 420 feet in Lake Michigan.
No further U. S. work with mixed-gas or oxygen scuba was undertaken until the outset of World War II. Dr. Christian Lambertsen, now Head of the Department of Pharmacology at the University of Pennsylvania, initially developed a streamlined, lightweight closed circuit oxygen apparatus which he offered in 1941, along with his own services, to the oss. This apparatus, called the laru—Lambertsen Amphibious Respirator Unit—was widely used and is, in fact, still described in the 1963 edition of the U. S. Navy Diving Manual. Lambertsen followed this in the early 1950s with an improved mixed gas model called Flatus. This unit was tested to 250 feet and was used for early dives on the Andrea Doria. These two Lambertsen units are the direct ancestors of our present U. S. Navy Mark v and Mark vi Mixed Gas scuba.
For the sake of completeness, note must be taken of one other mixed-gas scuba. In the early 1940s, a young Swedish engineer, Arne Zetterstrom, became interested in diving. He worked out several improvements in existing “hard hat” and submarine escape equipment, and soon became interested in mixed-gas diving as a means of going deeper and staying longer. He developed a system for using hydrogen-oxygen mixtures and made a number of successful dives, reaching 160 meters in 1945. Later that year on a dive to 50 meters, he lost control, blew to the surface, and died of the bends. Though there are certain physiological advantages to using hydrogen as the inert gas in place of nitrogen or helium, the handling problems of a potentially explosive gas mixture have generally precluded serious development of this mixed gas diving system.
Finally, there is the open circuit air scuba about which little more needs to be said. In the early 1920s a French naval officer, Captain Yves Le Prieur, became interested in the underwater world. He shortly became trained in helmet-hose diving equipment. By 1926, in order to give himself more mobility in pursuing his hobby, he and a friend developed a small open circuit air scuba, very much along the lines of present-day equipment. The apparatus had high-pressure cylinders on the diver’s back and a mouthpiece for breathing. It was, however, not a demand breather and consequently was very wasteful of the meager air supply. It was, however, widely demonstrated and publicized in France and Le Prieur is credited with having organized the first skin divers club—“Club of Divers and Underwater Life.” He also gave the world’s first scuba demonstrations at the International Exposition in Paris in 1937. Le Prieur’s apparatus was considerably improved upon in later models but it remained a free-flow scuba and very wasteful of air. It was not until 1942 when Cousteau and Gagnan developed their air saving, demand breathing device that the flood gate of open circuit air scuba was really opened. (By the way, the credit for coining the term scuba, which everyone should know stands for Self Contained Underwater Breathing Apparatus, belongs to the Bureau of Ships’ diving equipment engineer, Mr. Mike Foran.)
Even the astronauts are given scuba training as indoctrination for weightlessness. Perhaps there will be a requirement for some underwater exploration on the other side of the moon on some planet. But that is too far out for a “Bubble Head” to conjecture. Divers, however earthbound, can nonetheless take heart in the remark of the eminent British biologist and entomologist, Sir Julian Huxley. He was the principal speaker celebrating the 100th anniversary of Harvard’s Agassiz Museum of Natural Science. It was in 1959 shortly after Sputnik, the period of awakening and intense and excited interest in space. After giving due attention to space and to the possible interests of biologists, entomologists, and the like in what might be found on the moon, Sir Julian very tersely closed by saying—British accent, portly professor, pince-nez glasses, and all—“And frankly, I should much rather see the sea’s bottom, than the moon’s behind!”
A graduate of the U. S. Naval Academy with the Class of 1946, Commander Searle served in the USS Meredith (DD-890), Weiss (APD-135), and Providence (CLG-6). Subsequent to postgraduate training at George Washington University and M.I.T. where, in 1952, he was awarded the degree of Naval Engineer, he served at Charleston Naval Shipyard and Ship Facility, Subic Bay, and as an engineer advisor to the South Vietnamese and Royal Thai Navies. He graduated from the Naval School, Ship Salvage, Bayonne, N. J., in 1952, and has served as Philippine Area Salvage Officer and as head of the engineering department of the Navy’s Experimental Diving Unit, where he was co-designer of the Mark V mixed-gas SCUBA. After graduating from the Naval War College in 1962, he served as Fleet Salvage Officer, Pacific, and since 1964, has been Supervisor of Salvage, U. S. Navy. One of the Navy’s senior diving officers, he is a member of the DSSP and SEALAB steering committees.