Sea Monster: An Omega Planet Ocean Ultra Deep 6000M
Everything’s better, down where it’s wetter, take it from me.
Ultra deep diving watches pose a conceptual problem, which is that they are in general, when it comes to humans diving, a solution in search of a problem. The depth record for SCUBA diving was set by a COMEX diver in 1992: 701 meters, which exceeds the speculated 490 meter test depth of the Virginia class nuclear attack submarine and considerably exceeds the 100 to 200 meter depths experienced in modern saturation diving. For all intents and purposes any dive watch with a depth rating greater than 200 meters represents considerable overkill – in fact you could argue that 200 meters represents overkill for civilian sport diving which takes place at depths of 40 meters or less (130 feet). Having an extra margin of safety is reassuring but hardly essential; and watches designed for saturation diving are even more conspicuously outside the realm of practical necessity for swimming or recreational diving – in 2015, of the 3,300 commercial divers then active in the United States, only 336 were saturation divers, which is a small customer base for high depth-rated dive watches no matter how you slice it.
However, to make the point that a watch with a three or five or one thousand meter rating is laughably wasted on most of their owners, is to miss the larger point, which is that for many enthusiasts and lovers of high spec dive watches, among which I include myself, the yawning disparity between practical needs and the rated performance of the watch is a feature, not a bug. There is undoubtedly a frisson that comes with looking at your wrist and seeing something engineered to perform beyond all the bounds of practical necessity; it’s the same thing that drives prurient interest in the general automotive public about cars like the Bugatti Veyron, whose performance envelope also lies far outside the domain of realistic driving requirements. With that in mind, the appeal of ultra deep diving watches is easier to understand: the ability of a watch to tolerate extremes that would extinguish a human life instantly, becomes a proxy for human fascination with such worlds.
This I think is at the root of the interest to be found in a fairly recent addition to the world of ultra deep diving watches from Omega – in fact, the Ultra Deep, or Seamaster Planet Ocean Ultra Deep, to give it its proper name. The Ultra Deep comes by its name honestly; it has a depth rating of 6000 meters, which is roughly the depth of the abyssal plain of the ocean floor – a desolate place with a sparse population of animals with sluggish metabolisms eking out an existence on plankton, the occasional windfall of a whale carcass, and each other when they get half a chance. The human desire to explore inhospitable places increasing in proportion to their inhospitability, the deep places of the ocean have attracted intrepid and risk-loving explorers ever since the invention of the first submersibles, and in 2019 one Victor Vescovo, former US Naval Intelligence Officer turned entrepreneur turned explorer, set a new deep diving record in the submersible, Limiting Factor, which had been constructed to his specifications by Triton Submersibles in Florida.
For the record setting dive, Omega created a watch – three prototypes, to be precise – which were designed to tolerate the worst the abyss could dish out. The record setting dive took place in the Challenger Deep, the deepest known point in the Mariana Trench and Vescovo’s dive was part of the Five Deeps expedition in which he set out to explore – in Limiting Factor – the five deepest points in five oceans. The environment is hostile with a capital H – pressure reaches 16,000 pounds per square inch (atmospheric pressure at sea level is 14.7 psi). The Challenger Deep is aptly named; it was not explored until 1960, when Don Walsh and Jacques Piccard reached the bottom in the bathyscaphe, Trieste and it was another 52 years before their feat would be duplicated by James Cameron. Vescovo’s dives stand out because they’re dives, as in, more than one – of the 22 crewed dives to the Challenger Deep, 19 have been made by Limiting Factor, which remains the only submersible to have made multiple dives to the deepest point on Earth. The watch taken on the record setting dive was the Planet Ocean Ultra Deep Professional, which was rated by Omega to 15,000 meters – if you’re a fan of overkill in watch specs that’s about as overkill as it gets.
The direct result for the dive watch enthusiast public was announced in 2022 and it’s the one we’re looking at today for A Watch A Week. The Planet Ocean Ultra Deep is not quite designed for the environment at the bottom of the Challenger Deep but six thousand meters is still pretty incredible – external pressure is over 8000 psi, or four tons per square inch.
The construction of the watch reflects the environment for which it was designed. The case is in Omega’s O-Megasteel, which is a proprietary alloy (you can hardly consider yourself a self-respecting watch brand these days if you don’t have a proprietary alloy and preferably, more than one) with a couple of advantages over the standard 316L stainless used for dive watches. It’s nickel free, and as you can see it takes a variety of finishes very well but its main advantage over 316L is that its yield strength, which is the mechanical stress necessary to permanently deform the alloy, is twice that of 316L and it’s about 40 per cent harder as well.
The case is heavily built and 45.5mm x 18.12mm (I wonder just how much those dimensions would change at four tons per square inch of pressure). which while large, is not dramatically in excess of the dimensions of the 43.5mm x 16.1mm Planet Ocean 600M, plus if you happen to encounter a PO 600 while you’re wearing an Ultra Deep, you get to modestly point out that your watch is an order of magnitude more pressure resistance (if you have bragging rights, you may as well exercise them). The three Ultra Deep Professionals which dove attached to Limiting Factor are 55mm x 28mm, for comparison.
One notable difference between the Planet Ocean 600M and the Ultra Deep, is that the Planet Ocean 600M has an HEV – a Helium Escape Valve – built into the side of the case, while the Ultra Deep doesn’t. The HEV was introduced to dive watches in order to address a problem specific to saturation diving. “Saturation” in saturation diving refers to the fact that a saturation diver’s body is saturated with helium, which is used as a breathing gas (nitrogen, which makes up the majority of the Earth’s atmosphere, becomes toxic at saturation diving depths and so helium is used as a substitute). Helium atoms are small enough that under pressure they can penetrate dive watch gaskets and build up inside the case, and when saturation divers decompress after spending a week or more either working, or in a habitat pressurized to working depth, the pressure difference between the inside and the outside of the case can cause the crystal of the watch to pop off. An HEV is designed to give the pressure inside and outside the watch to equalize.
The question then arises as to why the Ultra Deep, which by its depth rating and construction is suited for saturation diving to put it mildly (plus it actually says it’s OK for saturation diving on the caseback), doesn’t have an HEV? The answer is that the other solution to helium getting into a watch case, is to simply construct the case so that helium can’t get inside in the first place. This usually involves a more robust gasketing solution but it does avoid the potential disadvantage of having another point in the case where the watch might spring a leak, although as a rule watches with no HEV and with cases designed to prevent helium ingress, are more heavily constructed.
Another difference between the Planet Ocean 600M and the Ultra Deep is that the Ultra Deep doesn’t have a display back, which is unsurprising given the depth rating; I suppose since there’s a sapphire crystal on the front of the watch that you could theoretically have a display back, but that would make an already thick watch, probably unmanageably thick. The crystal on the Ultra Deep is massive – 5.2mm, or over half a centimeter thick, and domed for better resistance to compression, so putting one on the back of the watch would definitely add height.
The depth rating of the Ultra Deep can easily feel, like many extreme numbers, like a bit of an abstraction but the engineering required demands a level of precision far beyond what you would find in a conventional diving watch. At 200 meters, water pressure is 231 psi, which is already considerable. As we’ve mentioned, at 6000 meters pressure is 8000 psi, so as you can see it’s really a entirely different engineering problem than making a standard dive watch. Machining tolerances have to be much tighter as variations which are insignificant at 200 meters can be catastrophic at 6000. To take an example from the Limiting Factor (which admittedly was designed for nearly twice that depth) the pressure hull was made of two titanium hemispheres, 90mm thick. These hemispheres had to have no more than 1/10 of a millimeter variation in thickness over the entire hull, as any irregularities would mean uneven pressure distribution, which might be enough to cause the hull to buckle or even implode.
Although the Ultra Deep is not designed for quite as extreme an environment, the same basic principles apply and it’s remarkable that Omega was able to make a watch capable of tolerating such pressure and still be wearable – if you look at the watch from the side it becomes clear that it’s essentially a high pressure vessel with the case middle built around it. The movement, caliber 8912 (which Omega also used in another sea monster, the Ploprof) is 29mm x 5.5mm, and the total thickness of the Seamaster Ultra Deep is 18.12mm which means that the “container” for the movement adds 12.62mm in thickness overall – which given the 90mm thickness of the hull of the Limiting Factor, starts to seem pretty reasonable if not downright remarkable. The research submersible Alvin, which has a spherical titanium hull and which is rated to 6500 meters and which is therefore a closer approximation than Limiting Factor to the engineering problems faced by the Ultra Deep, has a hull thickness of 74mm – you start to wonder less why the Ultra Deep is so thick, than wonder at how Omega managed to make it so relatively thin. On top of everything else the Ultra Deep is Master Chronometer certified – 15,000 gauss magnetic resistance, 0/+5 seconds per day, certified by both the COSC and the Swiss Federal Institute of Metrology.
And all that, I think, goes a long way towards answering the question of why such a watch is fascinating irrespective of its relevance to your daily life. While you won’t need to test its capabilities, wearing it means you’re wearing a remarkable piece of engineering the principles of which are relevant not just to horology, but to deep sea exploration, human exploration, and a set of challenges that have defined deep submersible diving since the beginning of its history. The fact that diving to 6000 meters is physically impossible is not really relevant – the fact that Omega created a watch capable of tolerating such conditions, however, is incredible.
The Omega Seamaster Planet Ocean Ultra Deep: case, O-Megasteel, with ceramic bezel and Omega Liquid Metal numerals, 45.5mm x 18.12mm, with O-Megasteel bracelet with micro-adjustment. Movement, Omega caliber 8912, co-axial automatic with 60 hour power reserve, Master Chronometer certified. Depth rating 6000 meters. The 1916 Company is an authorized retailer for Omega watches.