Nekton

With no previous experience to fall back on, the sappers taught themselves diving and developed their own techniques for underwater recovery and demolition. A success story that prompted the Royal Navy to establish the first Navy diving school (1843) staffed by those same army 'experts' whose job it was to teach sailors the principles of underwater salvage!

Although Siebe's diving helmet and dress had proven their worth, divers were still restricted in their ability to perform meaningful work at depths much below 60 feet. Umbilical hoses capable of handling high pressures and manual pumps capable of delivering the required amount of air to the diver remained limiting factors.

Gradually overcoming these setbacks, the Navy's interest in diving still remained largely focussed on military projects. Limited resources were available for commercial diving operations and insurance underwriters, intent on reducing their losses, were obliged to look elsewhere for people possessing the necessary skills and courage to challenge the ocean's depths.

"For whom the bell tolls"

In 1799, the 'Lutine', a British frigate carrying 1,000 bars of gold and 500 bars of silver, all insured for �900,000, sank in a storm in just 40 feet of water within sight of the Dutch coast. Despite numerous salvage attempts over many years, only the ship's bell and an insignificant amount of the cargo was ever recovered. For many years the Lutine Bell symbolised the perils of life at sea. Suspended in the offices of shipping insurers, Lloyds of London, its tolling indicated the loss of another vessel.

Salvaging a career

Springing a leak while riding at anchor in 1782, the large man-o'-war, 'Royal George', sank in 65-feet of water at the approaches to a busy UK naval port. Resisting attempts by the navy to raise her, the wreck posed a hazard to shipping. Because of their skills in demolition, army sappers were charged with its removal. A diving bell was employed for the task. But failing to make any headway with this device, the sappers eventually - in 1840 - turned to the newly developed diving helmet and flexible dress patented by Augustus Siebe in the previous year.

The days of wooden ships and iron men may have faded from memory but the legacy of early attempts to rescue precious cargoes from sunken wrecks and to free the crews of sunken submarines lives on.

Throughout the centuries the prospect of making vast fortunes hinged on sea trade, but at the mercy of the weather, pirates and enemy attacks, more early ships either foundered or were lost at sea than ever arrived at safe haven.

Even the locations of those that sank conveniently close to land could rarely be pinpointed with any degree of accuracy. And in those cases where their position was known the use of open-ended diving bells rarely proved adequate to the task. The problem of water depth still remained.

Dive equipment manufacturers like Siebe, Gorman & Co., provided ready-made solutions to the problem by employing some of the finest divers of their day. Notching up underwater feats of heroic proportions, many of these early salvage pioneers became household names.

"To boldly go �"

None was more famous than Siebe, Gorman's Chief Diver, Alexander Lambert. A short, barrel-chested man described by a contemporary as a 'pocket Hercules', Lambert became a national hero when, in 1880, a tunnel being driven under the Severn River, in the UK, flooded.

In order to pump it dry, engineers had first to close a heavy iron door deep inside the tunnel. Although the water depth was not great, any diver attempting the task had first to descend 200 feet down a shaft and then make his way in the darkness towards the door situated 1,000 feet along the tunnel.

Henry Fleuss, designer of a self-contained oxygen rebreather worn in conjunction with the heavy diver's helmet and dress, offered Lambert use of his new device. Neither designer nor diver were aware of the dangers of oxygen toxicity as Lambert made his way through the inky blackness towards the door where he discovered that the builder's rail lines running over the sill prevented the door from closing. With bare hands he removed one rail line before returning to the surface for a crowbar to remove the second rail.

Three years later, Lambert's services were again in demand when the Severn tunnel flooded for a second time. Luck was still with him. Although nearly succumbing to oxygen poisoning, he made his way back to the surface where he called for his trusty Siebe helmet and dress. With two other divers to pay out his hoses and lines, Lambert again managed to slam the door shut.

Deeper down.

Lambert's reputation for achieving the impossible made him the obvious choice for diver when, in 1885, the 'Alphonse XII' sank in 162 feet of water off of the Canary Islands while en-route to Cuba with a cargo of gold bullion worth �180,000.

Blasting his way deck by deck down through the wreck and into the strong-room, Lambert single-handedly recovered almost all of the bullion at depths never before achieved by a diver. But the price was high. Diving physiology was still imperfectly understood and despite apparent previous immunity to the crippling bends, Lambert at last succumbed and was obliged to retire from diving.

Throughout the second half of the nineteenth and into the early years of the twentieth centuries, the pace in successful deep diving had been set by civilian divers such as Lambert and his contemporaries. Relying more on guts than on intellect these early salvage diving pioneers risked crippling injuries and even death for the sake of reward.

By 1904, the deepest recorded dive had been performed by a team of Greek and Swedish divers carrying out an inspection on the hull of a sunken destroyer lying in 190 feet of water; a depth almost twice that of the 100 feet limit set by the Royal Navy on its own divers.

With little funding for scientific research, both military and civilian divers remained part of an 'obscure sect' who continued to suffer the effects of poor theory and dangerous techniques until a leading scientist, Professor J. S. Haldane, convinced the Admiralty to establish a commission tasked with studying diving and the effects of pressure on the human body.

Science steps in

Formed in 1906 the commission, headed by Haldane, sought the services of experienced divers "with brains, courage and patience" to act as human guinea pigs. He found such people at the Navy diving school. Gathering together a group of scientists and divers like, Lieutenant Damant and Petty Officer Catto, the team began to formulate the first valid decompression tables as they gradually achieved deeper and deeper depths: Trials that culminated in Damant achieving a depth of 210 feet and, after a series of decompression stops, ascending safely back to the surface. It was another eight years before a diver went deeper.

Although the United States Navy had established a diving school in 1882, by 1912 practically the only task that fell to its divers - restricted to a depth of just 60 feet - was the recovery of practice torpedoes in a test range.

Knowing of the work undertaken by Haldane and the Royal Navy, Chief Gunner George Stillson successfully lobbied for a similar programme of diving research and development. Joined by a surgeon who had studied at the Royal Navy Diving School, the team worked towards dives in excess of the 200-foot mark. In 1914 they achieved a depth of 274 feet in the open sea.

In setting these depth records both the US and the Royal Navies had practical aims in mind. When, in 1915, the U. S. Submarine F-4 sank off of Hawaii, in 304 feet, Navy Diver Frank Crilley reached the submarine in a dive that has rarely if ever been equalled by a helmet diver breathing compressed air.

Sharing their knowledge of decompression procedures and deep diving techniques with their civilian counterparts, salvage diving entered a new era of professionalism. The challenge that now remained was to find a breathing mixture other than air that would allow divers to safely go to even deeper depths and remain unaffected by nitrogen narcosis and oxygen toxicity.

Helium: Cream of the crop.

In 1919, Professor Thomson, (inventor of the cream separator) studied the effects of helium on animals and decided that, as an inert gas with low solubility, it would prove a suitable replacement for nitrogen in the breathing gas used by deep sea divers.

Although experiments with helium began in 1925, it was another twelve years before the US Navy Experimental Diving Unit began practical studies of its use in diving. In that same year (1937) when U.S. Navy physiologists had succeeded in putting a diver down to a simulated depth of 500 feet in a chamber, engineer, Max Nohl - who had similarly been working on the concept of helium as a replacement gas for nitrogen and who had designed his own helmet and equipment - made a successful dive to 420 feet in Lake Michigan. A depth later matched and exceeded by Navy divers who achieved 440 feet.

No longer suffering the debilitating effects of nitrogen narcosis, U.S. Navy divers were now able to perform meaningful work at depth. One of the most notable instances being the rescue of surviving crewmembers of the stricken submarine USS Squalus, in 1939, and its eventual salvage from a depth of 230 feet.

Determined to remain in the deep-diving race, the Royal Navy, in 1948, began i ts own programme to see how deep a diver could go in the event of deeper submarine sinkings. Helium, however, was in short supply. With the only known wells located in the United States and its export limited by Congress in order to deny Germany the possibility of building bomb-carrying zeppelins, Britain possessed only a small reserve of the gas acquired under the Lend-Lease programme.

Reclaiming the sea floor

In a series of dives made from, HMS Reclaim, moored in Loch Fyne, Scotland, the diving team progressively broke record after record while, at the same time, formulating new decompression tables. Dispensing with the American helium helmet, the Royal Navy adopted the Siebe, Gorman injector helmet and, to avoid lengthy in-water decompression, also used a Submerged Decompression Chamber (SDC). The final dive in the series was made by Petty Officer Bollard, who achieved a depth of 540 feet; a record that was to stand for another eight years.

In 1956, in a subsequent series of deep diving trials from HMS Reclaim, Senior Commissioned Boatswain, George Wookey, descended 600 feet into a Norwegian fjord where he performed a series of tasks designed to simulate those required by a diver rendering assistance to a sunken submarine.

It was the last time that a diver would descend to such depths wearing a bulky 'hard-hat' flexible dress and towing an umbilical hose connected to the surface. Future deep diving trials would employ entirely different equipment and techniques. And as military interest in deep diving waned, commercial interests would again come to the fore.