the leviathan’s lair Undersea Exploration and the History of the Dive Watch by jack forster Of all the various classes of wristwatches, perhaps none has traveled with man more often into a hostile environment than the dive watch. The history of the dive watch is very often the history of undersea exploration itself. Dive watches are a special breed because, remember, the deep blue isn’t just trying to kill you when you’re beneath the waves — it’s trying to kill your watch, too.
Watches can be about all kinds of things — art, ingenuity, history, craftsmanship, and venerable old men with fingers as deft as a lacemaker’s, working by candlelight through the long Swiss winters. But dive watches are different from the rest. When you get right down to it, dive watches, no matter what variations on a theme have spawned in recent years, are first and foremost about one thing only. Dive watches are about not coming back dead. Technology allows us to get ourselves into all kinds of trouble we couldn’t have gotten into without it, and perhaps no case is more to the point than surviving underwater. All life may have started in the ocean, but for animals like us that have spent the better part of the last half billion years figuring out how to survive outside it, staying alive underwater is the ultimate proof that sometimes you really can’t go home again. Dive watches are all about keeping track of how long it is before the little bit of home you brought down with you in the tank on your back runs out. Understanding dive watches means understanding a little about diving, which is not as new a business as you might think — probably for as long as human beings have existed, they’ve gone down to the water’s edge for food (if the oyster shells in Stone Age kitchen middens are any indication). For most of the time humans have been diving, though taking air down with you meant just what you could store in your lungs, which meant a dive time measured in seconds, or minutes at the most, that also made going much deeper than a few dozen feet out of the question for all but the craziest or most stubborn. Of course, at some point, some bright spark figured out that you could suck air through a tube — the snorkel was born, and since another thing humans have been doing since time immemorial is fighting each other, the combat swimmer was probably born shortly thereafter. Herodotus reports the exploits of a Greek sailor, captured by the Persians, who escaped and, with the aid of a hollow reed, swam undetected among their ships, cutting mooring ropes and wreaking havoc with the fleet (history has not recorded that he wore a Panerai, however).
Part I: Take a Deep Breath...
Diver Dan and the Hardhat Era The first divers, of course, weren’t wearing air in tanks on their backs. Instead, they were wearing spherical metal helmets with portholes for visibility, the design for which dates all the way back to their invention by Augustus Siebe, in 1837. Siebe, a former Prussian artillery officer turned engineer, relocated to England after the Napoleonic Wars, and was given the task of converting a helmet originally designed to allow breathing in smoky or polluted atmospheres (such as in a gas contaminated mine) for underwater use. His invention, in the form that eventually became known as the standard diving dress, consisted of a helmet, a waterproof canvas suit, and weighted boots designed to keep the diver’s feet below his head, as the weight of the helmet, even when filled with compressed air, had a tendency to make the diver perform an involuntary headstand. The standard diving dress, also known as a “John Brown” rig in the UK or a “Diver Dan” outfit in the United States, may look archaic today (and remind those of us of a certain age of the Tintin comic Red Rackham’s Treasure, to boot), but it succeeded in doing something that none of the previous attempts to allow work on the ocean floor had done: it permitted a diver to work with, at least to some extent, the freedom of movement one might enjoy on the surface. This is not to say that it was safe. Countless accidents claimed the lives of divers over the years — the fact that air came from compressors through air hoses from the surface meant that air lines could be vulnerable to fouling or damage, and the diver was unable to surface under his own power, meaning that he had to be hoisted to the surface. Misinterpretation of signals to surface support crews have led to diver deaths not just from failure to bring up a diver in trouble, but also from bringing a diver up too fast. Not bringing someone up fast enough to get air when their supply has been compromised is something pretty much anyone who has ever learned to swim can understand would be a problem. Water, it turns out, is not very much fun to breathe. But understanding how coming up too fast could be a problem is a lot less obvious. The reasons behind it weren’t understood completely until the early 20th century — as a result, a lot of people died, in pretty horrible agony, for reasons they didn’t quite understand. The problem was actually first noticed on dry land — or rather, under it. In the 1840s,
steam-powered air pumps were far along enough that they could be used to create higher than normal atmospheric pressure in mining shafts to help prevent flooding. However, miners sometimes suffered from painful muscle cramps, mental confusion, joint pain and other mysterious symptoms after emerging to the surface. Later, pressurized caissons, submerged chambers made of concrete that were filled with compressed air to keep water out, came into common use for harbor and bridge construction and maintenance work. Workers entered caissons through airlocks that maintained the difference in pressure between the outside atmosphere (equal at sea level to roughly 14 pounds of pressure per square inch of body surface — which is why if you suck the air out of a plastic soda bottle, it goes crunch in a hurry) and pressure in the caisson. Working too deep for too long meant a worker could suffer the same set of strange symptoms — sometimes fatal, often permanently disabling — that the miners had, and the disease got a name for the first time: caisson disease. For divers, the problem was, and is, the same. Come up too fast, and you run the risk of the same crippling agony, which nowadays is known as decompression sickness or, colloquially, “the bends”, due to the arched-back posture often assumed by sufferers. The reason behind the disease has to do with that soda bottle we mentioned parenthetically just a second ago. That the soda bottle goes crunch from atmospheric pressure when you don’t, is due to the fact that your body is basically full of fluids — your blood, the fluid inside every cell in your body, the fluid in your joints and in between the membranes around your nerves and brain. Inside, you’re wet as wet can be. And yet, every cell in your body needs a gas — oxygen — in order for you to survive. So, in you breathe, and with every breath you Jacques-Yves Cousteau get a lungful of atmosphere, which here on Mother Earth means about 21 percent oxygen and 78 percent nitrogen, with traces of this and that thrown in (like carbon dioxide and methane, which exist to give politicians something to argue about, and climatologists something to worry about). Because your body fluids and the outside atmosphere are an open system, the pressure exerted by the gas in your body automatically equalizes with atmospheric pressure. So, the reason you’re able to inflate your lungs, despite the fact that you’ve got 14 psi of pressure trying to crush your rib cage, is because the pressure outside and inside your lungs is equalized. Those gases also end up dissolved in your blood and body
fluids, and gases in solution exert just as much pressure as when they’re not. Think again of a soda bottle but, this time, imagine that the soda’s still in it. You can see the soda in the closed bottle before you crack open the screwtop, and there ain’t much in the way of bubbles — the gas (carbon dioxide) is in solution. But take off the top, and the higher pressure inside the bottle suddenly equalizes with the lower pressure outside, and suddenly you’ve got bubbles galore and soda down your pants. So far so good — what happens when you breathe gas underwater, at higher than atmospheric pressure? Well, underwater breathing gear is designed to deliver air to your lungs at ambient pressure — that is, the pressure of the water around you, which goes up the further down you go. The deeper you go, the higher the pressure of the gas you breathe — again, otherwise you wouldn’t be able to inflate your lungs against the pressure of the water around you — and the more gas dissolves into your blood and body fluids. Now, if you come up nice and slow — if you ascend at a carefully predetermined rate, making decompression stops — then the extra gas slowly comes out of your body fluids, just like when you open a soda bottle slowly. You can hear the steady hiss of gas escaping, but there’s no sudden cascade of bubbles. In fact, if you don’t go too deep or stay down for too long, you don’t need to make decompression stops at all. But if you do go for long and deep, and you don’t take your time coming up, then you’re a human soda bottle with the top taken off too fast — bubbles form in your blood, in your joints, in your brain and around your nerves, and you are one unhappy camper.
if you do go for long and deep, and you don’t take your time coming up, then you’re a human soda bottle with the top taken off too fast
Freedom of the Seas — The Advent of the Aqualung and SCUBA The real trick, then, in moving around freely underwater — swimming like a fish, without being tethered to the surface with hoist lines, air hoses, and (by 1916) a battery powered telephone line, which was the cumbersome lot of the man in the standard diver’s dress — was to develop a way of delivering a mixture of breathable gases to a diver under a pressure that could vary with the ambient water pressure as the diver went up or down. This proved to be a tough nut to crack. Such a device, called a demand regulator, wasn’t invented until 1937, but the inventor, Frenchman Georges Commeinhes, was killed near the end of the Second World War, in 1944. By this time, two of his fellow countrymen had also produced their own demand regulator: Émile Gagnan, a French engineer who would go on to create innumerable technical breakthroughs in diving, but remain relatively unknown outside professional circles; and a man destined to become a household name worldwide — the head of the French Navy’s underwater research group, Commander JacquesYves Cousteau. Cousteau and Gagnan’s was the first fully functional demand regulator to come into general use, and by the end of the war, the Aqualung, as it is properly known (though the term later
The standard diving dress, also known as the “Diver Dan” outfit
surface shipping, is not, however, a fulfillment of the age-old dream of moving like a fish through the ocean. For that to happen, a way had to be found to free undersea adventurers from the guts of their iron fish. Air, in other words, had to be made portable.
eonardo da Vinci is said to have The master himself, developed what appears to have Leonardo da Vinci been a primitive underwater breathing device. He wrote in the Atlantic Codex that he didn’t want to describe his diving apparatus in detail, for fear it would be used to sink ships and commit murders — a puzzling scruple from someone who otherwise designed military hardware with gleeful abandon. His hesitation, though, reflects the sentiment that there is something uncanny, to say nothing of downright unfair, about prosecuting a war underwater, and indeed, the common sentiment for much of recent naval history — certainly amongst surface fleet sailors — is that snapping a torpedo into the flank of a ship from some tin fish cowering under the surface is not quite cricket. Spending any significant time moving freely underwater, though, had to wait until the 19th century. Prior to that, the only way to go down and stay down for any length of time was to use a diving bell — its basic principle is familiar to anyone who’s ever turned a cup upside down in a tub of water to trap air inside it. The diving bell or its descendant, the submarine, which by the First World War was playing merry hell with
complication became generic) was being used by A scuba diver ascends to the surface French demining and underwater wreck-clearing teams. Yet in the years before the war, another technology had been invented — one that was to revolutionize undersea exploration as much as the Gagnan-Cousteau Aqualung, and become one of the sharpest tools in the undersea warrior’s kit: the oxygen rebreather. The rebreather (originally called a SCUBA unit, with the acronyms standing for Self-Contained Underwater Breathing Apparatus) was like the Aqualung in delivering pressurized air to a diver, but it was unlike the Aqualung in one important respect — as the name implies, it takes the air the diver exhales and recycles it. This is done by means of a chemical scrubber that removes carbon dioxide. Just enough oxygen is added back in to keep the breathing mixture at the right proportion of gases. The first rebreathers were invented in 1878 by Siebe, Gorman and Co. (the company founded by the same Siebe who invented the standard diving dress), and by 1910, had been adapted by Siebe, Gorman and Co.’s president, Sir Robert Davis, for escape from sunken submarines as the DSEA — the Davis Submerged Escape Apparatus. After the First World War, it became popular among Italian spear fishermen in the Mediterranean, and was, eventually, adopted by the Italian Navy’s commando dive teams as well as by British frogmen. Rebreathers were, and are, especially attractive to military units for two reasons: The first is that since the time in compressed atmosphere chambers on support vessels, and gases are recycled rather than exhaled, rebreather units tend not to are transported to and from the work depth by special pressurized produce telltale bubbles that give away the presence of frogmen to transfer chambers. surface observers. The other attractive element of rebreathers is that With all the advances in diving technology, just how deep can you they allow divers to spend longer periods of time submerged than go? The record for the world’s deepest scuba dive is 1,083 feet (330 conventional Aqualungs, again, because gases are recycled. One of meters), and all sorts of problems make even going much less deeper their dangers, however, is that if for some reason they fail to function suicidally challenging. However, millions of people enjoy recreational correctly, and carbon dioxide absorption or oxygen delivery fail, panic diving in relative safety every year. (A recreational dive being one that and seizures or, even more dangerous, sudden blackouts can occur requires no decompression stops, uses only ordinary compressed air without warning. They have their advantages, but their greater as a breathing gas, and doesn’t go deeper than 130 feet. Oh, and bring complexity can make them more potentially risky as well. a buddy.) While modern electronic dive computers have become the Since the end of the Second World War, probably the single biggest mainstay of keeping track of dive time, ’twas not always thus. As we’ll advance in diving has been the advent of saturation diving, in which see, “how long have I got” has always been the single most important divers — typically breathing a gas mixture in which helium has been question that a diver can ask. And so, for as long as there have been substituted for nitrogen, which can cause disorientation when breathed divers, watchmakers have created watches to help keep even a shallow in at high pressure for prolonged periods of time — spend days or weeks dive from becoming an early grave. Besides, if it’s a good idea for you in special high pressure habitats that allow them to work for repeated to have a buddy, maybe bringing along a buddy for your dive computer long periods underwater without losing valuable work time to lengthy isn’t a bad idea either. decompression cycles. Saturation divers generally spend non-diving
Published on Dec 17, 2012