Authors: Brad Matsen
Sixty years before
Les Mousquemers
were experimenting with the Aqua-Lung, another Frenchman, Paul Bert, discovered the effects of nitrogen under pressure on the bodies of air-breathing animals. Decompression sickness was known most commonly as caisson disease because bridge builders, tunnel diggers, and others who worked below sea level under pressure in sealed boxes called caissons were its earliest known victims. After working a ten-hour shift under pressure of more than 2 atmospheres, many men emerged from the caissons with crippling pains in their joints that sometimes proved fatal.
Bert theorized that the pain of caisson disease—some called it the bends, because a victim was often unable to stand upright or straighten his limbs because of the pain—was caused by some kind of imbalance in the relationships of the various gases in air. He tested his hypothesis by subjecting twenty-four dogs to pressures of 10 atmospheres, equivalent to a depth of 297 feet below the surface, and brought them back to one atmosphere in one to four minutes. Twenty-one of the dogs died; one showed no symptoms at all; the other two were in pain but recovered.
When Bert dissected the dogs afflicted with decompression sickness, he discovered that bubbles of nitrogen had formed in the tissues of their muscles and organs. In the dogs that had surfaced slowly, there were no bubbles. The nitrogen dissolved in body tissues as the pressure decreased gradually. When it decreased suddenly, nitrogen bubbles formed. The phenomenon was analogous to the absorption of carbon dioxide in champagne. With the cork in the bottle, the gas under pressure is dissolved in the liquid. When the cork is popped, the pressure is relieved and the carbon dioxide is released as tiny bubbles.
The solution was obvious. Caisson workers—and later divers—had only to return to the surface gradually to allow the bubbles of nitrogen time to pass harmlessly into the blood, or spend less time under pressure. Bert subjected another group of dogs to the same pressure as the first group, but brought them to the surface slowly in one to two hours. They suffered no ill effects at all.
Bert noted that once a caisson worker had been stricken with decompression sickness, the symptoms could be relieved by returning to the pressure at which the nitrogen had dissolved in his tissues. He tested this part of his hypothesis again with dogs, and discovered what would eventually become recompression treatment in hyperbaric pressure chambers for caisson workers and divers who had the bends.
Bert also discovered that breathing a gas that contained no nitrogen—pure oxygen, for example—would also reduce the symptoms of the bends. The gas containing no nitrogen simply forced the nitrogen bubbles out of the worker’s tissues.
After Bert’s pioneering work on decompression sickness, Scottish physiologist John Scott Haldane followed in 1905 with mathematical models showing precisely how much gas under pressure was absorbed by the different kinds of organs and tissues in an air-breathing body. Haldane used goats instead of dogs for his experiments because goats were closer in size to humans. From his research he derived tables that specified the amount of time a diver had to spend at various depths during his ascent to rid his tissues of nitrogen. Haldane’s tables were published in 1908 in the
Journal of Hygiene
, adopted by navy divers in Europe and the United States, and two years later made available to the public. Cousteau had a copy.
Les Mousquemers
dove on
Dalton
for two weeks, venturing inside the wreck to salvage crockery, silverware, glasses covered with coral, ship’s lanterns, the oak steering wheel, and other loot. After a dive into what Cousteau reckoned was the captain’s cabin, he returned to the surface with a crystal vial of clear liquid. Later, Simone uncapped the vial, took a whiff, and said the contents were a very fine prewar perfume.
Foreshadowing what would become generations of shipwreck divers who decorated their homes and garages with artifacts from their discoveries, Dumas’s hunger for treasure was insatiable. “On
Dalton
, Didi gathered a lot of curious loot,” Cousteau said. “He found stacks of crockery, silverware, glass bejeweled with corals, and a large crystal bowl. One day, he found a midden of ouzo bottles and thin Metaxas brandy bottles. He sawed off the oaken bridge wheel and dove repeatedly for dishes and silver. We suspected that he was collecting household gear for a wedding he had failed to mention.”
For the rest of the summer, Cousteau and his band of divers filmed shipwrecks. During every minute underwater, they learned from experience. Near Marseille, the freighter
Tozeur
lay in 65 feet of water, the victim of a mistral that had blown it from its anchorage and onto a rock in the outer harbor.
Tozeur
taught them that the hull of a wreck could be coated with razor-edged clams that lacerated their bare flesh as they brushed against them. The cuts were painless under
water, but on the surface they hurt like bad insect stings. They named the clams “dog’s teeth.”
Tozeur
also introduced them to scorpion fish, which were ugly as toads and could inject a crippling venom through the spines on their backs. Tailliez was the first victim, after which everyone kept a wary eye out for the almost invisibly camouflaged nightmare.
Les Mousquemers
tracked down wrecks with charts and firsthand accounts of sinking ships. In a cafe in the village of Cavalaire on the Côte d’Azur, a farmer told them the story of the Spanish freighter
Ramon Membru
, which had slammed into the rocks on an afternoon in 1925. The ship stuck firmly aground, a massive shape looming over the village, until a few days later, when a tug pulled it off and towed it to the harbor. That night, as
Ramon Membru
lay at anchor apparently safe and sound with its cargo of Spanish cigars, the ship caught fire, burned to the waterline, and sank. Cousteau, Dumas, and Tailliez found the remains of
Ramon Membru
a few hundred yards from the town jetty, all but invisible in the weeds that covered the burned and sea-torn hull. They filmed the ghostly outlines of the ship but found nothing of interest aboard the wreck. The highlight of the dives to
Ramon Membru
, and the film they shot there, was a herd of fish called
liches
, each the size of a man, that patrolled the wreck.
Off the coast near the village of Port-Clos they found a newly sunken fishing boat with nets and rigging still on its deck, which gave them the idea of filming a trawl net in action. Until then, fishermen had only been able to imagine what their nets were doing underwater. Cousteau hired a trawler captain and his boat, and set up with his camera on the bottom in 60 feet of water. The trawl slammed past Cousteau, destroying sea grass and bottom-dwelling creatures, while most of the fish leaped like rabbits to elude the gaping mouth of the net. The damage from a single pass of the trawl on the bottom devastated the near-shore areas of sea grass and other fish habitat. Dumas later hung, head down, on the tow rope to film what went into the net. The film from his camera revealed that a very small percentage of fish in front of the net were caught.
They explored and filmed another form of coastal destruction in Toulon harbor, where the 150-foot deep-sea tug
Polyphème
was scuttled along with the rest of the French Mediterranean fleet.
Polyphème’s
last assignment had been to open and close the antisubmarine net at the entrance to the harbor. A year after it was scuttled, the old tug lay
in 60 feet of exceptionally clear water with the tip of its mainmast only 4 feet beneath the surface.
Polyphème
looked just like a tugboat under way with a slight starboard list, but sailing on the rocks and sand of the bottom instead of the surface of the sea. Inside,
Les Mousquemers
found that
Polyphème
’s crew had stripped their ship clean before opening the sea cocks and sending it to the bottom.
Nearby, according to a warning circle on the harbor chart, lay the wreck of the cargo ship
Ferrando
, which had gone down fifty years before. A local mariner told Cousteau that its location was marked by a buoy, probably placed there by a fisherman who had lost a net on the wreck. Dumas made the reconnaissance dive alone, descending 100 feet down the buoy line to explore
Ferrando
. The wreck had been plundered by hard-hat divers, who had cut a hole in its side that illuminated the cargo hold when he swam inside the hull. He found only a few china plates, and some lumps of coal that the minerals in seawater had turned from black to grayish green. The 300-foot-long wreck was festooned with nets and surrounded by the headstone-like upright black shells of giant mussels that sprouted from the sand on the bottom.
Exploring around the stern, Dumas found a single Japanese porcelain sake bowl, which he added to the crockery in his salvage bag. He checked his watch, which told him he had to ascend immediately or face a long decompression stage. He took a last look at
Ferrando
, turned to scan the open plain around him, and saw a rule-straight pathway cut into the sand and pebbles of the bottom. The strange road ran as far as he could see in the dimness of the light at 100 feet, a puzzling apparition that dominated Didi’s report to Cousteau and Tailliez on the surface. They returned the next morning, but when they reached the approximate spot of the wreck the mooring buoy was gone. They dove all day but found no trace of
Ferrando
or the mysterious road on the bottom of the sea.
“Didi put the sake bowl and the crackled dish in his new house in Sanary, and a visitor who asks about them receives an interrogation on what he might know about Roman roads on the bottom of the sea,” Cousteau said.
When they weren’t exploring and filming shipwrecks,
Les Mousquemers
continued to test the limits of their Aqua-Lungs. In October 1943, after four months and hundreds of dives, Dumas talked Cousteau and
Tailliez into letting him be the guinea pig for a rigorously controlled test to find out how deep their wonderful new device could take them. They had been to depths of 135 feet several times since their descent to the stern section of
Dalton
off Planier light, suffering only the ear squeeze that had disoriented Cousteau. They carefully decompressed from dives during which they stayed for more than a few minutes on the bottom below 60 feet, and so far, none of them had experienced the symptoms of the bends.
On Maire Island off the coast near Marseille, Cousteau arranged for government witnesses from the local fishing village to verify the depth of Dumas’s descent as measured by a 300-foot length of knotted rope. Dumas would simply tie his weight belt to the rope at his deepest point, and ascend to the surface with no fear of the bends because of his short time at the maximum depth. The signatures of witnesses would strengthen the case Cousteau, Émile Gagnan, and Air Liquide wanted to make to the French navy and other customers for the Aqua-Lung.
In the early evening, under threatening skies and with sea conditions at a whitecap chop and building, the test flotilla of two launches anchored off the island in 240 feet of water. They dropped the rope over the side, its end weighted by an anchor, and carefully tied the upper end to the rail of the boat. Cousteau descended first, stopping at the 100-foot knot from which point he would be able to reach Dumas quickly if he got into trouble. A minute later, Didi plunged past him, heavily weighted to speed his descent. Cousteau watched the bubbles from Dumas’s regulator flowing away in the strong current, and saw Didi fighting to stay near the rope, which was streaming from the vertical. Dumas was flailing, and the bubbles from his regulator increased—a sure sign that he was hyperventilating in distress. Just as Cousteau was letting go of the rope to swim to the rescue, he saw Didi kick furiously. Seconds later, Dumas rocketed past Cousteau on his way to the surface.
Exhausted, Dumas told Cousteau and Tailliez what had happened. As he had passed the 120-foot knot, his vision had begun to blur and he started to obsess on the rope, the knots, its texture. Worrying about his eyes and the rope amused him rather than frightened him. He felt wonderful, counting knots as he went down, forgetting about Cousteau above him, the people in the launch, and the fact that he was diving to set a depth record. His ears were buzzing, he had a bitter
taste in his mouth, and he felt so drowsy that he could barely keep his eyes open. He wanted to go to sleep, but had the vague feeling that he should stay awake. Dumas noticed the rope again, took off his weight belt, clipped it to a knot, and swam toward the light above.
In wartime France,
Les Mousquemers
knew nothing of the recent work of an American navy officer on the phenomenon of nitrogen narcosis, calling what had happened to Dumas “rapture of the deep.” U.S. Navy captain A. R. Behnke studied the drunken euphoria that sometimes turned hard-hat divers giddy at depths of more than 100 feet and had killed many of them. He found out that nitrogen narcosis was caused by a combination of nitrogen saturation and excess carbon dioxide in nerve tissues, and could be alleviated by mixing helium into a diver’s air supply.
When they pulled up the rope, Didi’s weight belt was tied onto the knot at 210 feet. It was a world record for a free-swimming Aqua-Lung diver, to which the witnesses attested with their signatures on a certificate Cousteau had prepared in advance.
Back at home in Sanary-sur-Mer, the routine of the war years went on—scrounging for food, avoiding confrontations with occupying troops, and making the best of the worst of times. Cousteau and
Les Mousquemers
continued to shoot underwater and test the limits of the Aqua-Lung. They edited hundreds of feet of film into a movie called
Épaves (Shipwrecks)
. It was under thirty minutes long, with no story line, but the moving picture of men swimming underwater around sunken ships enchanted everyone who saw it.
Among the first audiences to see
Épaves
was a roomful of admirals in Toulon who were stunned by the obvious military potential of the Aqua-Lung. Georges Commeinhes, Cousteau’s closest competitor in the race to find a way to breathe safely underwater, was killed just days before the end of the war. During the liberation of Strasbourg, he was in command of a tank destroyed by a satchel charge thrown by a retreating German. Cousteau, Gagnan, and Air Liquide were then unopposed in their campaign to sell their Aqua-Lung to the French navy.