Dive Watches
But try to buy these ticking masterpieces of cool and you’ll feel backhanded by reality. ‘Cause in the real world, watches like Tom Cruise’s Bulgari multi-function super-computer from Minority Report or Roger Moore’s buzz-saw bezeled Rolex 5513 Submariner from Live and Let Die simply do not exist. That was, at least, up until 1999, when reality unleashed a horological counterpunch that all but knocked cinema out for the count. Because that year, the world bore witness to what was possibly the coolest wristwatch ever created: a diving super-computer forged from titanium and housing the first mechanical depth gauge ever found in a timepiece. Even the watch’s name - the Deep One - smacked of a John-Holmes-like hyper-endowment. The watch flung down the gauntlet, stating: “Take that, cinema! We defy you to create something cooler.” And the sad thing is, since then, cinema never has.
THE FIRST ACT IN THE DIVE WATCH REVOLUTION - IWC’S DEEP ONE
If you started with a blank page to create the ultimate diving watch, what would you shortlist as your key features? This was the question IWC engineer Richard Habring asked himself while sitting on the deck of a dive boat during his holiday. Then, after consulting with dive masters as to what would comprise the ultimate submersible wrist instrument, an idea coalesced in his mind: it would be made from titanium, that recently declassified military material also used frequently in aviation, surgery and nuclear power plants. Titanium was totally anti-corrosive with a strength-to-weight ratio that was off the charts. The watch would have an internal rotating bezel for the ultimate security in recording elapsed dive time. It would also feature a depth gauge, so that if your dive computer failed, you could use that as a vital backup tool. In short, in an emergency situation, it would be perfectly equipped to save your life.
The next thing to be established was that the watch would have to be 100-percent mechanical, in deference to the brand’s history in mechanical timepieces. A purely mechanical watch was also dependable in a way that an electric watch wasn’t. If well maintained, it would function in perpetuity, while an electronic watch would need to have its battery changed regularly. But beyond this, a purely mechanical watch would never be a slave to the almost engineered obsolescence present in all electronic devices. Such is the nature of the binary beast that in a few years’ time, as with mobile phones, computers and now digital cameras, it is guaranteed that superior technology will replace it. A mechanical watch, even one with a depth gauge, could always be repaired by a skilled watchmaker. With these in mind, IWC set out to go where none had dared. How did it create a mechanical depth gauge for this ultimate dive machine? It looked to one of the most proven techniques of measuring pressure.
To understand how the Deep One works, we need to go back to the Industrial Revolution. The era of steam engines allowed major advancements in travel via locomotive, and industrial manufacturing. But steam engines could also be dangerous if pressure was not regulated using blow off valves. As pressure increased, it approached a threshold between efficient energy production and explosive danger. To accurately gauge this threshold, engineers turned to a device called the Bourdon Tube, invented in 1849 by a French scientist and watchmaker named Eugène Bourdon, and capable of measuring pressure up to 100,000 pounds per square inch.
The principle behind the Bourdon Tube is simple: a closed metal tube acts as a pressure-sensing element. The tube is coupled to a pressure source, and once pressure enters, it causes the tube to straighten. Conversely, less pressure causes the tube to coil. This motion is transmitted via a special linkage system to a hand that indicates pressure on the face of the gauge. Several of the components in this linkage come straight out of a watchmaking textbook, including a toothed rack system, not unlike that in perpetual calendars, and retrograde watches, proving that Bourdon’s joint expertise in science and watchmaking made him uniquely suited to transfer technology from one discipline to another.
As man began to explore the seas, he discovered that the Bourdon Tube device allowed him to accurately read water pressure at different depths. A Bourdon Tube depth gauge works in exactly the same way as a Bourdon Tube pressure gauge. In the depth gauge, instead of pressurized gas, water enters the sealed tube. At greater depths, when water pressure is higher, the Bourdon Tube straightens out, placing greater tension on the linkage system and causing the hand on the depth gauge to rise higher. In shallower water where water pressure is lower, the tube coils tighter, releasing tension on the gauge’s hand and causing it to return towards zero.
When it was released, the Deep One was a revelation. It was a space age-looking, true super-computer for the wrist, achieved entirely through artisan watchmaking techniques. Some controversy arose around the Deep One’s decidedly un-deep depth rating of 100 meters, but it is important to understand that this depth rating has nothing to do with the company’s waterproofing abilities. By 1982, IWC had already achieved a staggering water resistance rating of up to 2,000 meters with its Ocean 2000 titanium dive watch. Even more impressive was that this watch achieved the rating without the use of a helium release valve, as was found on the next deepest rated watch of the time, the Rolex Sea Dweller. When asked how IWC was capable of this, the company’s technical director Kurt Klaus told us, “Just make the watch well enough that helium doesn’t enter it to begin with, and it becomes a non-issue.”
In fact, the 100-meters depth rating of the Deep One was stipulated in order to protect the sensitive depth gauge mechanism. The logic is simple: the Deep One uses an open-element Bourdon Tube device to measure water pressure. The more water pressure exerted on it, the greater it deforms. But if you look at the diagram of how the Bourdon Tube is placed inside the watch case, you can see that space is tight. As such, there are limits to how much the Bourdon Tube can alter its geometry. For this reason also, the depth gauge mechanism is calibrated to read up to 45 meters - any further deformation of the Bourdon Tube is not possible in the limited space. As the manual for the Deep One explains: “To avoid possible damage, the depth gauge is protected by a mechanical device from about 50 meters, and will not register depths below this level.” But there is yet another reason that IWC capped the depth measured by the Deep One to 45 meters: Bourdon Tube depth gauges are most accurate in depths of 40 meters or less.
So, how do you use the Deep One? The watch comes equipped with an air pump that is easily attached to the valve through which water enters. Before each dive, you use the pump to fill the Bourdon Tube with air, to ensure that the gauge is good to go. Just before submerging, you set the internal rotating bezel to mesh with your minute hand to show elapsed dive time. The depth gauge is made up of two overlaid hands in a configuration similar to the hands of a split seconds chronograph. As you descend into the sea, the hands will move together, providing you with a reading of your depth on the perimeter of the dial. Once you reach the deepest depth of your dive, the yellow deepest depth hand will remain in place, even after you resurface. To reset this, you simply press the same crown used to set the internal rotating bezel.
An interesting question is that of how varying altitudes could be compensated for in the Deep One. As air pressure at sea level is greater than air pressure at higher altitudes, this will have an effect on the Bourdon Tube device in the watch.
Now that they had identified the technology on which to base their mechanical depth gauge, how did IWC transplant the Bourdon Tube into a relatively flat watch just 44 mm in diameter? For starters, Jaeger-LeCoultre’s ultra-flat automatic caliber 891 was selected to drive the timekeeping function. At that time, both manufactures were headed by the same person - the legendary Günter Blümlein. As such, sharing of calibers and technology was common. The remaining work focused on building a super-accurate yet tiny Bourdon Tube, which could still have enough space to vary its geometry according to water pressure.
To compensate for these changes in altitude, the depth gauge hand can be manually zeroed using the crown at four o’clock, which is integrated into the valve for the Bourdon Tube. The Deep One begs the question: how would Bourdon feel about the co-opting of his pressure gauge to create the world’s first mechanical depth gauge-equipped timepiece? As Bourdon was a watchmaker, we are inclined to believe that he’d be pleased with the reconciliation of his industrial implement with the high alchemic art of haute horlogerie.
Launched in 1999, the titanium-cased Deep One rippled with innovations beyond the depth gauge, including a rotating internal bezel activated by an additional crown at nine o’clock. In watches with external rotating bezels - despite the fact that these bezels are uni-directional - a hard blow, or accidental contact with a reef, can cause the bezel to rotate on its own. However, with an inner rotating bezel, the crown controlling rotation is tucked out of the way. Beyond this, IWC arrived at a brilliant system: once the watch is submerged beyond several meters, the water pressure acts on the crown that controls the inner rotating bezel, so that it becomes deactivated. Turning it underwater will have no effect on the preset timing on the bezel. When you return to the surface, the crown is automatically unlocked and you can once again turn it. This single innovation, though rarely talked about, represents a vast measure of safety built into the ultimate dive watch. Today, this feature is also found in all contemporary IWC Aquatimer watches, which also feature internal rotating bezels.
Now, almost a decade after its launch, much has been made of the sensitivity and need for servicing of Deep One watches. But here’s another take: the vast majority of Deep One watches were purchased as investment pieces and remained unused inside watch safes for several years. As with other complicated watches, this is very possibly the worst way to store them. Those rare few who have actually used the watches as they were intended, have found the experience rewarding. As Arthur, a NAUI instructor based in Hamilton, Bermuda, states, “Love it… 57 dives and still in great shape. Everything works.”
For those chasing this beast of a dive watch, very few of them were made, as the amount of labor necessitated in setting up the Bourdon Tube device made for extremely time-consuming assembly. Says Jonathan King, an avid diver and IWC’s Hong Kong brand manager, “The Deep One was assembled in the same room that we reserve for high complications, and we consider it precisely this type of watch.” Those chasing the Holy Grail of dive watches might want to take note that a disproportional large number of Deep Ones made their way to Australia and New Zealand, where the diving culture is rich. Jaeger-LeCoultre has since launched a dive watch replete with a brilliant depth gauge device that registers depths of up to 80 meters, which arguably represents the highest evolution of intelligent dive watches to date (until, of course, IWC’s much rumored Deep Two emerges in 2009 to celebrate the ten-year anniversary of the original watch). In the meantime, the original 1999 Deep One still represents immense historical value as the very first and most significant act in the story of intelligent dive watches.
THE WORLD’S MOST ADVANCED DIVING WATCH - JAEGER-LeCoultre’s MASTER COMPRESSOR DIVING PRO GEOGRAPHIC
Jaeger-LeCoultre’s history in dive watches stretches back to 1959, when it created the world’s first dive watch with an alarm that could be set to signal the end of elapsed dive time, named the Memovox Deep Sea. Then, in 2007, Jaeger-LeCoultre launched an all-new dive watch that, again, catapulted the manufacture to leading position in mechanical dive watches: the Master Compressor Diving Pro Geographic.
With this watch, your eyes are naturally drawn to the left-hand side of the titanic 46.3 mm case, where the pressure-sensing device for measuring depth is placed. What Jaeger-LeCoultre refers to as the watch’s membrane comprises 24 elements, and represents 1,500 hours of research and development. It takes two hours to assemble, and provides a reading of depth to within one meter, up to 80 meters. Look closely, and you’ll find a rectangular opening devoid of sapphire crystal, exposing the alchemic inner workings of the membrane.
Like the Bourdon Tube, Jaeger-LeCoultre’s membrane system relies on varying degrees of deformation caused by water pressure to derive a depth reading. But it differs from the Bourdon Tube device in three very significant ways. First, the entire system remains outside of the watch, meaning that water never enters the watch, as it does in the Deep One. This eliminates the risk of debris finding its way into the watch. Second, while the Bourdon Tube relies on the elastic property of metal to return to shape consistently, constancy of the membrane’s variable geometry is controlled by a special spring. This offers greater ease in achieving consistency, and also greater ease in repairing or calibrating the system. Finally, because the membrane system has a finite travel, after which additional pressure has no effect on it, the watch can be brought beyond its 80-meter maximum displayed depth, with no ill effect.
The head of the system is fixed to a rail, which is what moves when water pressure is exerted on the head. There is a transmission pinion that translates the vertical travel of the rail into a dial-side reading of depth. When you dive, pressure is exerted on the head of the system. The deeper you descend, the more pressure is experienced. This causes the rail to compress further, translating to a greater depth reading. The maximum pressure that can be exerted on the head is 9.9 kg, which corresponds to the 80-meter depth limit of the gauge.
What allows the systematic contraction and return of the depth gauge’s membrane as water pressure rises and then diminishes? Surrounding the rail mechanism is a specially calibrated spring that allows consistent and accurate travel for the rail at all times. The correct functioning of the entire membrane is dependent on the correct calibration of the spring. If the stiffness coefficient is not high enough, the depth gauge will show a reading greater than the actual depth; and if the stiffness coefficient is too high, it will show a depth reading that’s less than actual depth. Further, the stiffness coefficient of the spring must remain constant over numerous contractions and expansions, and must also be consistent throughout its range of motion.
The contracting membrane by pressure is innately connected to Jaeger-LeCoultre’s history. One of the brand’s most famous innovations is the Atmos clock, that requires no winding and which derives energy purely from tiny variations in environmental temperature or pressure. Says the brand’s CEO Jérôme Lambert, “Inside the Atmos is also a membrane that contracts and expands according to environmental temperature. The only difference is that inside the Atmos is a gas that expands or contracts. The solution that we have achieved is a spectacular demonstration of how we’ve used our rich history and the total integration of our manufacture to solve age-old problems with totally new solutions.”
Every aspect of the depth gauge system has been optimized for robust performance. The movement of the rail is translated via the transmission pinion to a rack system. This rack interacts with a centrally mounted snail cam through geared teeth, which drives the blue depth gauge hand to sweep around the perimeter of the dial.
The scale for depth is printed on the chapter ring, which has been divided into sub-sections of 20 meters, each distinguished by a different color. The segmentation was suggested to Jaeger-LeCoultre’s design team by professional divers, so that at a glance, you can determine your approximate depth. In addition, the predominant color used for key indications in the Master Compressor Diving Pro Geographic, as well as other watches in the dive collection, is blue. Why blue? Because studies have determined that at between 30 to 60 meters below sea level, blue is the only color that still remains chromatically true.
This entire rack system is not tucked away behind the watch dial, but on full display; adding to the visual pyrotechnics on the dial, yet in a way that it does not distract from the critical time- or depth-reading functions. Says the watch’s designer Magali Metrailler, “Owners want to have interactivity where they can see how their watch functions. With the tremendous innovation of our mechanical depth gauge, we were very enthusiastic to place the mechanism on display.”
While much has been made of the fact that pressing the head of the gauge allows you to demonstrate the principal of this extraordinary function to friends, a critical benefit to this has been somewhat overlooked. In other watches with depth gauges, the wearer must actually descend to depth or be fitted with an additional apparatus to determine if the depth gauge is functioning. With the simple yet innovative design architecture of Jaeger-LeCoultre’s depth gauge, you can test if your depth gauge is functioning by simply pressing on the head of the system and observing the movement of the depth gauge hand. This adds a huge margin of safety during pre-dive safety checks.
THE HYBRID OPTION - PANERAI’s LUMINOR 1950 SUBMERSIBLE DEPTH GAUGE
While IWC and Jaeger-LeCoultre have had long histories as high watchmaking brands before creating depth gauges, the story of Officine Panerai reflects an inverse pattern. Founded in 1860, Panerai first developed its expertise in patented luminous substance and the creation of military devices, one of which was the depth gauge. So successful were Panerai’s depth gauges that they formed the cornerstone of the trittico: a combination of dive watch, compass and depth gauge that was standard-issue equipment for Italy’s naval commandos during the Second World War.
Panerai’s depth gauges were calibrated in two versions, both using the Bourdon Tube system, which is the most reliable and accurate at shallow depths. The first version read depths to 15 meters and was used primarily for attack missions where divers would swim out to enemy objectives at relatively shallow depths, to either place ordinance on hulls, or guide their torpedoes to deadly destinations. The second version was rated to 30 meters and used for what the Italian Navy termed “defense missions”.
The idea of combining two of the key components of Panerai’s legendary trittico was certainly not lost on its dynamic CEO Angelo Bonati. He explains, “We started working on the Submersible Depth Gauge five years ago. It took such a long time because we wanted to attain the certification as a professional diving instrument from the Swiss Federal Office for Metrology (METAS) in Bern. That’s why we used the electronic mechanism for the depth gauge. We also worked for a long time on a fully mechanical watch, including the depth gauge. But because it is a highly innovative system, I’m not sure when we will release it. For us, if we create a diving watch with a depth gauge, it has to be certified as professional equipment on the same level as any of the dive computers used by recreational scuba enthusiasts.”
Bonati had tested several mechanical depth gauges before deciding on an electronic one. The Luminor 1950 Submersible Depth Gauge watch, at 47 mm in diameter, features a titanium case and a uni-directional rotating bezel. The depth gauge registers pressure using a silicon diaphragm that interacts with water pressure through the thin fins in the watch back. But the movement driving the time and date indications is mechanical - a reliable Valjoux-7750-based caliber with the chronograph functions suppressed.
The depth scale is located on the outer perimeter of the dial. At the end of the scale is the “off position” resting place for the depth gauge. When you press the small push-piece at ten o’clock, the gauge is activated, and its hand automatically travels to the deepest dive reading during the previous dive. Press it again for six seconds; it returns to zero, and you can begin your dive. The watch takes a measurement for depth every 1.25 seconds with a margin of error of about 20 centimeters. At any time during the dive, you can check your maximum dive depth by pressing the push-piece at ten o’clock. After six seconds, the hand will return to your current depth. The maximum dive time is four hours, and the battery of the depth gauge mechanism is good for 500 hours. When battery life is diminished, the depth gauge hand will move slowly between the off and zero positions.
While the implementation of electronic technology is markedly different from the depth gauges created in its past, Panerai’s history in the creation of the devices gives it great legitimacy to create this type of timepiece. When asked if there was a further project to unite the trittico in one watch, Bonati states, “Basically, we have a project for this, but I don’t think it is the right moment for us to release the watch. Maybe we won’t have all three complications in one watch, because you risk becoming a little bit excessive. But the combination of compass and watch, yes, we have already done, and you will see it one day.”
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