Hermetic wristwatch, 1930.

Last Updated on May 28, 2025 by Jason

In my daily search for vintage watches, I came across this very interesting Hermetic wristwatch dating from 1930. At first glance, it looks a little odd because it appears to be missing the crown. However, the crown exists. It is just hidden inside the innovative “hermetic watch case”. This was one of the early attempts at producing a truly waterproof watch. I have spent a considerable amount of time researching the design and history of this fascinating piece of watchmaking history. I can share what I have uncovered below.

Hermetic wristwatch

The movement is signed underneath the dial with the reference FHF3, for Fabrique d’Horlogerie de Fontainemelon, a Swiss watch movement manufacturer. The dial has its original hands, although the luminous detailing has been removed at some stage in its life. Overall, the case is in good condition, as is the crystal. The watch includes a vintage leather strap. The dial has hairline cracks, which could be “sympathetically refinished”, but most collectors prefer the patina. These cosmetic defects are common for enamel approaching 100 years of age.

The watch measures 34mm in diameter, excluding the fixed wire lugs. The case is silver and there are British hallmarks inside the case back and the dust cover for Edinburgh 1930, together with a sponsor’s mark for Arthur Rendell. There is also a Brevet (patent) number of 89276 inside the case, which relates to a 1921 application regarding the case design, ie, “a watch with a protective box”. The watch case is a hermetic case, or double cased, designed by Jean Finger, a case maker of Berne, Switzerland. The same model of case was supplied to various watch makers, including IWC and Rolex.

Swiss patent CH 89276

Jean Finger’s 1921 Swiss patent (brevet) CH 89276 introduced a novel “protective box” or double-case design for wristwatches. The patent for the “Montre a remontoire avec boitier protecteur” or “watch winder with protective box” included a sketch (Rolex Hermetic Wristwatches at Vintage Watch Straps). It showed a complete inner watch (with its dial, movement and crown) housed inside an outer shell with a screw-on bezel and hinged back. To wind or set the time, the wearer unscrews the outer bezel and glass to reveal the inner case. Then using a finger nail under a small tab at 4:00 the watch is hinged upwards so the movement can be wound and set as usual using the crown at 3:00. When closed and screwed down, the outer case encloses the inner watch in a sealed chamber, providing protection against dust and moisture. The name “Hermétique” was used to market these watches.

Limitations of the Hermetic design

Despite its ingenuity, the Finger hermetic case had practical drawbacks. Winding the watch was inconvenient. The bezel and crystal had to be fully removed, and then the inner case had to be hinged out before the crown could be turned. In simple terms, to wind it, the outer bezel must be unscrewed to expose the inner watch, a tedious process once a day. As a result, the inconvenience of this design never endeared itself to the public. In other words, consumers preferred easier-sealing cases. Also, the protection was not absolute. In modern terms, Finger’s case is better described as merely water-resistant. Without a rubber or lead gasket, the screw-down case still allows very limited leakage over time.

Adoption by watchmakers

Finger’s hermetic case design saw limited but notable use in the 1920s. Many manufacturers produced Finger‑case watches in the early 1920s, and documented examples include Rolex, Eberhard, IWC, Zenith, Marvin, West End, and others. In 1923, Hans Wilsdorf (Rolex) purchased exclusive rights to the design. He obtained a British patent (May 10, 1923) and introduced Rolex Hermetic and Submarine models. In practice, hermetic double cases were a 1920s phenomenon. The bulk of known examples date from about 1921 to 1930. By the early 1930s, superior waterproofing solutions became available (e.g. Rolex’s Oyster screw‑down-crown of 1926). Only a few thousand double-case wristwatches were made, making them quite rare today.

A brief history of Fabrique d’Horlogerie de Fontainemelon (FHF)

According to Grail Watch Wiki, FHF was founded in 1793 by Isaac and David Benguerel, with Julien and François Humbert-Droz. Operating as Benguerel & Humbert, FHF became the world’s oldest manufacturer of watch ébauches. In 1816, it opened its first factory and pioneered industrial production of watch movements.

Throughout the 19th century, FHF expanded rapidly. It opened a second plant in Corgémont in 1838 and adopted steam power by 1862. By 1876, it employed 400 workers and produced 240,000 ébauches per year. In 1900, director Paul Robert modernised production by installing American-style machinery. In 1925, FHF merged with Landeron and helped found Société Suisse des Fabricants d’Ébauches (Ebauches SA) in 1926. Under Ebauches SA, FHF supplied movements to many Swiss brands. After World War II, it focused on mass-producing affordable, entry-level calibres.

In 1955, FHF launched the low-cost “Standard” movement, which dominated the market. By the 1960s, the Standard calibre 608 became the most-produced movement worldwide, with over 40 million units. In 1979, FHF introduced the “mini-quartz”, then the world’s smallest watch movement. However, the quartz crisis forced a major restructuring of Swiss watchmakers. By 1985, ETA had absorbed FHF as part of the Swatch Group. FHF became known for reliable, mass-produced movements that supported the growth of affordable Swiss watches. It pioneered industrial watchmaking and occasional technical innovations, particularly miniaturisation.

FHF 3 movement

I must admit, there is quite a lot of guesswork here. I wasn’t able to find any specific documentation for the FHF 3 movement. According to Ranfft DB, the FHF 1 to FHF 16 movement groups contain calibres of different dimensions. The most likely movement in this instance is the FHF 3 13‴, which had a diameter of 29.33 mm.

Produced by FHF in the early 20th century, the FHF 3 is a small manual-wind watch calibre. It appeared in modestly sized wristwatches, often trench or officer-style designs popular between the 1920s and 1940s. The FHF 3 typically used 15 jewels, as per this example. The movement operated at 18,000 vph, a common frequency for watches of this era. Power reserve was generally around 36 to 40 hours, typical for hand-wound movements of the time

Technically, the FHF 3 13‴ was a straightforward ¾-plate manual-wind calibre with a small seconds sub dial located at 6 o’clock. Early examples used a simple lever escapement with a bimetallic screw balance, a Breguet hairspring and offered no shock protection, which was common for the period. The FHF 3 13‴could be found in a range of unbranded and smaller-brand wristwatches during its time. Overall, the movement supported modest mid-century wristwatches often sold under generic Swiss brands.

Summary

This is an interesting watch for a collector, as it holds a significant place in watchmaking history. The hermetic case represents a stepping stone on the way to providing the first practical water-resistant watch. But, practical, this watch wasn’t. The requirement to unscrew the bezel daily to simply wind the watch was its shortcoming. Nobody wanted the inconvenience, and the hermetic case failed to entice the public. Not only was the task of unscrewing the bezel inconvenient, but the repetitive task also risked damaging the delicate thread and therefore the “waterproof” seal. I think this is a museum piece, rather than a vintage watch you can enjoy wearing. I wouldn’t say no to this Hermetic wristwatch if it were a gift, but I suspect it would spend the rest of its life wrapped in cotton wool.