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Sherpa recreates the original EPSA Super Compressor case Sherpa recreates the original EPSA Super Compressor case

Sherpa recreates the original EPSA Super Compressor case

Time+Tide

Dive watches are more popular than ever, especially compressor divers. These ubiquitous watches herald from a time when horological engineering was at its peak, and when man’s explorative mind had no limits. Compressor divers were built to withstand submersion whilst remaining relatively thin and were therefore comfortable to wear. This was made possible by the creation of the bayonet-style case with its spring-loaded caseback that tightened its seal the deeper one goes. (More on that later.) EPSA, the inventor and original manufacturer of these cases, ceased operations in the 1980s. But people loved how these watches looked, so much so that many compressor-style divers have emerged in the past few years. 

Enter Sherpa Watches. While some brands do make actual super-compressor divers using spring-loaded casebacks, most brands do super-compressor style watches. This means having an inner rotating dive-time bezel and a second crown at the 2 o’clock. But that is as close to the original EPSA super-compressor as they would ever get. Sherpa went two steps beyond to re-create the EPSA case and Monoflex crown, two patented technologies that made this style of watches popular when they first came out in the 1950s. Sherpa, by the way, is a nod to a collection of Enicar watches that debuted these ultra-capable watches. 

A Little Bit of History

As soon as the first professional divers were released by Rolex, Blancpain, and Doxa, something was clear: they could be improved. Back in the 1950s, rubber gaskets used to seal the case-backs were not made the same way they are today. Overtime, gaskets would dry up and crack under constant pressure, making water ingress inevitable. A solution had to be found in order to guarantee that a diver could be water-resistant at all times. Enter the EPSA super-compressor case and it’s spring-loaded caseback. The idea was that there was no reason to apply tremendous pressure on the gasket whilst on land. Only when diving. 

The idea of using a spring-loaded caseback was genius: the deeper one goes underwater, the more pressure would be applied on the gasket. Therefore, the tighter the seal when it was needed. As mentioned above, this technology was invented by EPSA in the 1950s. (EPSA stands for Ervin Piquerez SA.) Once the company closed its doors in the 1980s, no one was making this type of case anymore so brands stopped designing true compressor divers. They only made super-compressor style cases. Because one would have had to buy or recreate the machinery required to make EPSA cases. This, inevitably, would have increased the retail price of their watches. 

But let’s go back to Enicar, a prominent Swiss tool watch company that closed its doors in the late 1980s. The brand released a collection of ultra-durable watches known as Sherpa. These Sherpa were equipped with the bayonet case and two other inventions: the Monoflex crown and the inner-rotating bezel. The Monoflex crowns differed from regular crowns found on divers in two ways. First, they did not screw-down. Second, one had to pull the crown out to operate the bezel. The idea of the inner rotating bezel came from the need to reduce condensation inside the case and further protect the movement. 

Re-Creating the EPSA Case and Monoflex Crowns

Sherpa Watches’ founder, Martin Klocke, is a German engineer born in Switzerland. He set out to recreate watches that herald from the Golden Age of human exploration, the 1950s. The time when Sir Edmund Hillary and Tenzing Norgay ascended Mount Everest for the first time. In that same decade, Enicar sponsored a team of Swiss alpinists who also successfully climbed Mount Everest. These were times when Swiss brands started to make robust watches made for land and sea exploration. As we saw above, this led to the creation of the super-compressor case and the Monoflex crown.

However, one might ask how did Martin re-create the original? How can one claim to have done so? 

Well, the patents EPSA had registered became public domain and Martin found them, studied them, and worked with watchmakers and engineers to re-create the case exactly as EPSA made them. This involved manufacturing special machinery to re-create the parts that go into making the bayonet case. For example, the spring-loaded screws or rings that made this style of case unique. Martin used the same approach to re-create the Monoflex crown. He found archival drawings of the crowns and the company that used to make them. The latter gave Martin their technical drawings and blessing to re-engineer the crowns himself. 

Martin displayed a level of commitment rarely seen from an independent brand owner.  

The Modern Sherpa OPS and Ultradive

The modern Sherpa watches, the OPS and Ultradive, homage some of the most iconic Enicar models. The OPS comes with a DLC case while the Ultradive comes with a polished stainless-steel case. As we now know, these two models are the closest to the original EPSA super-compressor watches. And they have more than one trick up their sleeves. Their cases measure 40mm in diameter, 49.3mm lug-to-lug, and 13.5mm in thickness. They come with 200 metres of water resistance, a domed sapphire crystal with inner anti-reflective coating. Furthermore, the hands and indices have been endowed with thick layers of SuperLuminova X1 lume. 

Powering the OPS and Ultradive is what the brand calls the Mantramatic MM01 caliber. It is a Top Grade Sellita SW200-1 movement that Martin takes apart to laser-engrave a traditional Tibetan Buddhist mantra on two of its wheels. Since the wheels are in perpetual movement, they emit vibes of love, wisdom, and compassion out in the world. This is definitely something unique that adds a never-seen before value to watches that are technical masterpieces. Just like the wheels are laser-engraved by Martin, he also assembles the watches himself in Germany with German parts.

From a visual standpoint, the OPS and Ultradive offer two different wearing experiences. The OPS is black and stealthy, where the matte baton-style hands contrast with the matte black dial. The first 15 minutes on the dive-time bezel are highlighted in white, a colour also found on the painted hour markers. The date window at the 6 o’clock has a white disc and printed numerals in red. As it would be the case on a chronograph, the seconds hand is highlighted in orange. The OPS is a legible diver that leans heavily on the utilitarian side given its DLC coating and overall black colour scheme. 

For its part, the Ultradive is more versatile. The hour markers are applied and come with brushed tops and polished sides that reflect the light in different ways. The dial layout is simpler and cleaner, with a fully graduated minute track that spills over onto the inner rotating bezel. The stainless-steel case is fully polished and complements the white bezel insert. An interesting design detail lies in the seconds hand that comes with two lollipop elements instead of the typical one. This makes the seconds hand look like a flag that smoothly runs across the dial. 

Final Thoughts

Earlier in the review I mentioned that no watchmaker had continued making the EPSA compressor case. No one had until Martin entered the watch scene and decided to do it himself. One might say that doing so was a ballsy move given that it would be complicated and expensive. Well, it was. The results, however, are two marvels of horological engineering that revive a lost era of robust tool watches. However, making things well always comes with a higher price tag. Although you can only take my word for it, the OPS and Ultradive are truly worthy of your attention. 

Sherpa OPS and Ultradive pricing and availability:

The Sherpa OPS and Ultradive are available now for order from Sherpa Watches. Price: €5,800 (€4,873.95 exc. VAT) (Sherpa OPS), €5,900 (€4,873.95 exc. VAT) (Ultradive)

Brand Sherpa
Model OPS
Ultradive
Case Dimensions 40mm (D) x 13.5mm (T) x 49.3mm (L2L)
Case Material Stainless steel with DLC coating (OPS)
Stainless steel (Ultradive)
Water Resistance 200 metres
Dial Black, domed with internal rotating bezel
Crystal(s) Domed sapphire with AR coating
Strap Black tropic style
Movement Mantramatic MM01, Sellita SW200 top grade base
Power Reserve 38 hours
Functions Hours, minutes, seconds, date
Availability Now
Price €5,800 (€4,873.95 exc. VAT) (Sherpa OPS)
€5,900 (€4,873.95 exc. VAT) (Ultradive)