Part II. Putting the Pieces Together – Transitional Case Designs
As described in Part I, wristwatch case design foundations were established during the latter half of the 19th Century. Several names stand out for their early innovation of key design features adopted later by household name watch producers. Waltham (Dennison, Fitch and Twing), Droz and Borgel each contributed importa
nt pieces – e.g., threaded bezel and case back, modular design without bezel or case back opening, threaded crown and packing or gland seals – or improved their use in overall case designs providing enhanced resistance to the elements.
By: Scott Burton* Co edited by Mitka
Thus, many of the key components for “modern” case design already were available at the turn of the century, and were starting to be assembled for specialized use by a few producers such as Tavannes and Fortis. In turn, these transitional designs would be refined later by companies destined to become household names, such as Omega and Rolex – in large part owing to their success marketing cases that could withstand the rigors of military and sporting applications.
Tavannes Submarine Commander (Ca. 1915)
In December 1917 the Horological Journal reported a “waterproof” wristwatch designed to the specifications of two British submarine commanders. A source familiar with this watch reports it was introduced a couple years earlier, employing a threaded bezel and case back, both fitted with compressible gaskets, and a compressed gland seal in the stem tube to resist water intrusion where the winding stem enters the case.
May 1916 Submarine Watch Advertisement*
In 1916 a “Submarine” watch meeting this description was advertised by Brook & Son of Edinburgh, although the maker is unconfirmed. During WWI, Tavannes supplied similar “Langbourne” branded watches to Birch & Gaydon of London, employing a threaded bezel and case back design but without a stem tube packing ring, and lacking gaskets to seal the bezel or case back. The Langbourne and Submarine watch reference numbers are very similar, suggesting the Submarine case may have been a refinement of Tavannes’ Langbourne watch case design. This speculation seems corroborated given the Submarine watches were powered by Tavannes-Cyma calibre 3B.
Tavannes Submarine Case Stem Tube Packing Gland*
The Submarine case design was quite practical relative to earlier screw-down crown designs. The Tavannes design omits threads on the stem tube prone to wear, and eliminates the inconvenience of unscrewing and re-screwing the crown for winding. Unlike screw-down crown designs, the Submarine case remains waterproof even while winding or setting the time; and the user need not remember to screw down the crown after winding to make the watch waterproof again. Indeed, although not broadly commercialized, the Tavannes Submarine case previewed the configuration adopted by many later water resistant designs foregoing a screw-down crown, Omega’s Seamaster being just one well known example.
Fortis Aquatic (1915)
In February 1915 and August 1916 Paul Ernest Jacot and Auguste Tissot submitted Swiss and UK patent applications for a water-resistant case design. The patents were granted in February 1916 and August of 1917, and appear to have been licensed to Fortis, which registered the trade name “Aquatic.” Produced without a brand name on the dial, it seems some Aquatic watches were supplied to Rolex and Zenith, and later Harrods.
Harrods’ Fortis Aquatic
The Aquatic featured a threaded case back, but no bezel, thus eliminating one case gap requiring a seal. Rather, it employed gaskets to seal the crystal. Like Borgel’s 1891 design the Aquatic relied on a spring to hold down the crown – but Jacot and Tissot added a gasket to further inhibit water intrusion. It appears, however, that the Aquatic’s water resistance could be significantly reduced as the crown gasket deteriorated, or if neglected to be replaced during servicing.
Rolex Oyster (1926)
In October 1925 Paul Perregaux and Georges Perret applied for a Swiss patent on a screw-down crown design. Shortly after the patent was granted, Hans Wilsdorf acquired the patent in July of 1926 and obtained British, German and US patents for the Perragaux-Perret design. Wilsdorf had been anxious for an innovative case design to provide true dust and water resistance. But Rolex – or perhaps Aegler, their trusted movement supplier – soon recognized the Perregaux-Perret screw-down crown suffered from the same flaws as the 1881 Fitch design given its lack of a clutch. To address this shortcoming Aegler adjusted the Perregaux-crown to add a clutch, a refinement already accomplished by Waltham in 1881.
Rolex Oyster Case Patent Diagram
In 1926 Rolex combined Aegler’s adapted screw-down crown design with a threaded bezel and case back, resulting in the Oyster case. As with earlier screw-down stem models the early Oyster provided a good seal with the stem fully screwed down, but required its owner to unscrew and then re-screw the crown daily to keep the watch wound. Failure to fully screw the crown tightly after winding presents risk of water intrusion in such designs.
The crown and stem tube threads also are prone to rapid wear and require periodic replacement due to daily use over an extended period, although this weakness was reduced after Rolex introduced its “Perpetual” self-winding movement in 1931. In the same year, Rolex also introduced a tool to tighten the case back, providing a greater seal than could be accomplished by hand-tightening. By then, however, Borgel’s earlier case design also had been adapted to incorporate a tool-tightened case back, combined with an integral stem seal providing greater convenience and reliability than the screw-down crown for routine active wear.
Taubert Improved Borgel Case (1929)
By 1924 François Borgel’s already well-regarded case manufacturing company was acquired by Taubert & Fils. The Tauberts quickly improved on Borgel’s earlier threaded case design by developing a patented stem seal in 1929, and went on to become pioneers in stainless steel case manufacturing techniques. Taubert’s cork stem seal provided the benefit of not needing to unscrew the crown every time the watch required winding – avoiding the risk of losing its sealing capabilities if the owner neglected to fully re-screw the crown after winding. By providing an integral stem seal, the case remained sealed even during winding or setting the time.
In this respect Taubert’s stem seal was similar in concept and function to earlier designs employing packing rings or glands at the stem, such as Dennison’s 1872 design and the Ca. 1915 Tavannes Submarine case. But Taubert also improved Borgel’s threaded case design, in 1931 adding a “Decagonal” screw-down case back featuring ten flat surfaces to aid in tightening, thus enhancing the seal. Given its convenience and reliability, it’s no surprise the new Taubert case was a hit. Over several decades it was adopted by many top watch producers – including the likes of Patek Philippe and Vacheron Constantin, among others.
West End Watch Co. Sowar Prima,
British Military Model?
One of the earliest and perhaps most famous wristwatch lines to employ Taubert’s Decagonal case was West End Watch Company’s Sowar Prima. Originally founded by Alcide Droz & Fils to supply watches to the Indian market, West End introduced the Sowar Prima in 1934. It’s worth note the Sowar Prima also was among the earliest watches to incorporate the then-new Incabloc shock protection technology, making it one of the most resistant models on the market. Indeed, as a testament to its durability in hard duty, the Sowar Prima reportedly was issued to British military forces in India and the Middle East, and to Indian military forces under British command. Many vintage models carry an arrow symbol on their case backs which some believe to be a variant of the British military “broad arrow,” while others claim it’s an alignment index.
Omega Marine (1932)
Up to this point, the need for a true dive watch simply did not exist. In 1934, however, Omega took on the challenge, basing its Marine dive watch on Louis Alix’s Swiss patent CH 146310. The Omega Marine prevented winding stem leakage by encasing the entire watch within a second, external case. The Marine’s internal case was fitted with a gasket at its shoulder, which was compressed when inserted into the external case, held in place by a spring-loaded clip. When submerged, increasing water pressure further compressed the two cases, resulting in a more effective seal with greater depth. The Alix design required removal of the interior case for winding, but this was a minor inconvenience for a purpose-designed tool watch not intended for everyday wear.
Omega Marine Ref. CK679
In 1936 an Omega Marine was tested by submerging for 30 minutes in Lake Geneva at a depth of 73 meters. In 1937, the Suisse Laboratory for Horology in Neuchâtel certified the Marine case to a pressure of 13.5 atmospheres, or 135 meters – the first official tests to confirm the capabilities of a true, purpose-designed dive watch. Among other early testamonials, the Omega Marine was used by aqualung inventor, French Navy Commander Yves Le Prieur, and by the American explorer Dr. William Beebe, famous for the 1934 “Bathysphere” descent. Although not practical for consumer-focused models, variants of Omega’s design harnessing external water pressure to enhance case seal compression were later developed by Roamer in 1941, and Ervin Piquerez SA (EPSA) in 1955.
Panarai Radiomir (1936)
In the 1930s the Regia Marine contracted with Officine Panerai to supply a true dive watch for Italy’s Royal Navy frogmen commando corps. Lacking its own manufacturing capabilities, Panerai turned to Rolex for a purpose-designed dive watch, employing a 47mm adapted version of the early Oyster case. The first “Radiomir” watches were supplied in 1936, with luminous dials as the name suggests.
Early Panarai Radiomir
The earliest Radiomir model lacked the oversize crown guard that has since become synonymous with Panerai. Perhaps ironically, the now iconic crown guard was a later addition to remedy the Oyster case’s inherent weakness. Like early Rolex Oysters, early Radiomirs employed manual movements requiring daily hand-winding; consequently, the crown threads and gasket were prone to rapid wear, compromising water resistance. The Radiomir crown guard was designed to keep the crown seal compressed, preserving water-tightness.
Transition to “Modern” Case Designs
As these examples illustrate, early case design innovations of the late 1800s set the stage for iconic transitional designs such as the Rolex Oyster and Omega Seamaster; destined to become household names in large part due to their robust case construction. While many of these transitional designs adopted features introduced previously, they often improved on earlier designs and combined multiple features to enhance case resistance and function. But the early 1900s were not without innovation – Omega’s Marine, for example, harnessed external water pressure to enhance the case seal, and the company’s Seamaster took advantage of technological advances in synthetic gasket materials.
By the middle of the 20th century the industry was poised to take these design features to new levels, and to a growing consumer market anxious for watches that could withstand the rigors of sport and tool use. Stay tuned for Part III of this series, surveying iconic modern wristwatch case designs!
(c) Copyright 2021 P. Scott Burton & Mitka Engebretsen, all rights reserved. Follow on Instagram, @rex.tempus
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