The Blancpain Bathyscaphe 37.4 mm to Mark the Collection’s 70th Anniversary

37.4 millimetres is a rather unusual size for a modern diving watch. With the Fifty Fathoms Bathyscaphe Ref. 5903-1110-63A, limited to 300 pieces, Blancpain is marking the 70th anniversary of the model range by revisiting the 1968 design – visually faithful to the original, yet technically firmly rooted in the present.

From the Fifty Fathoms to the Bathyscaphe

In the 1950s and 1960s, the cultural significance of diving changed. The underwater world was no longer the sole preserve of military units, professional divers and researchers; it also became the setting for a growing leisure culture. With this new audience, the role of the diving watch also changed: for recreational divers, it still had to be easy to read and robust underwater, and feature a rotating bezel, whilst at the same time fitting into its owners’ everyday lives.

Blancpain dates the creation or launch of the Fifty Fathoms to 1953 and describes it as a watch developed for professional diving. However, the name ‘Fifty Fathoms’ was not registered as a trade mark in Switzerland until 11 June 1954 (No. 151378); this was followed on 19 June 1954 by a patent application for the design features of the watch case and the adjustment ring (CH322328). Blancpain had already mentioned the year 1953 in a Rayville/Blancpain advertisement from 1957. However, no independently verifiable contemporary production or delivery document that unequivocally documents the manufacture of a Fifty Fathoms as early as 1953 is known to exist. Blancpain then dates the launch of the Bathyscaphe to 1956. It was smaller in diameter, more understated in design and tailored to the needs of recreational divers, without compromising on the key features of a diving watch. The result was not merely a scaled-down version of the Fifty Fathoms, but a standalone model for the civilian side of diving.

A return to the proportions of 1968

Blancpain chose a 1968 Bathyscaphe as the template for the anniversary model; with its compact proportions, narrow bezel, baton-shaped hour markers, grey dial and domed crystal, it particularly clearly embodies the characteristic design of the model range. This fidelity to the original is continued on the dial: Blancpain uses its historic logo and positions the date display at three o’clock, just as in 1968.

Old versus new: the 1968 Bathyscaphe (left) and the new Bathyscaphe from 2026 (right)

The new Fifty Fathoms Bathyscaphe Ref. 5903-1110-63A draws heavily on the design of its historic predecessor, whilst incorporating contemporary materials. The unidirectional rotating steel bezel now features a scratch-resistant ceramic insert, whilst a domed box-shaped sapphire crystal covers the dial. 

37.4 millimetres – not too small, not too large

The polished stainless steel case measures 37.4 millimetres in diameter. This makes the new Blancpain Bathyscaphe significantly smaller than most current diving watches. The other dimensions also reflect this compact format: the width from lug to lug is 46.5 millimetres, whilst the lug width is 18 millimetres. This makes the watch suitable even for slimmer wrists.

It is certainly not flat, however. A height of 12.3 millimetres is more noticeable with this diameter than it would be on a larger watch. The box-shaped crystal contributes to this, whilst the narrow bezel leaves comparatively plenty of space for the dial. Viewed from above, the Bathyscaphe therefore appears larger than its 37.4-millimetre diameter would suggest. Furthermore, in typical Bathyscaphe fashion, it is water-resistant to 300 metres.

Historic colours, modern luminescence

The sunburst finish causes the meteor grey dial to shift between light and dark shades of grey depending on the angle of the light. The baton-shaped hands and hour markers are crafted from 18-carat white gold and feature beige Super-LumiNova in the ‘Old Radium’ shade.

Credit © Tim Vaux

However, the name refers solely to the beige colour of the luminescent material. Technically, this modern luminescent material has nothing to do with the radium used in historic diving watches. In daylight, it is intended to evoke the look of aged luminous markers with a patina, whilst in the dark, the triangle at the 12 o’clock position on the bezel glows green.

The watch is supplied on a chocolate-brown calfskin strap. This looks the part, but doesn’t quite match the 300-metre water resistance: anyone wishing to take the Bathyscaphe into the water will need a different, water-resistant strap.

You can find out more about the 38 mm versions of the Fifty Fathoms here in our article

In-house calibre 1150 with a 100-hour power reserve

Inside, the automatic in-house calibre 1150 displays the hours, minutes, central seconds and date. With a diameter of 26.2 millimetres and a height of just 3.25 millimetres, the movement is exceptionally slim. It consists of 210 components and features 28 jewels. Running at 3 hertz, or 21,600 vibrations per hour, it offers a 100-hour power reserve. In practical terms, this means that if you take the watch off on Friday, it should still be running on Monday without needing to be wound.

Credit © Tim Vaux

The silicon spiral also provides the movement with extensive protection against magnetic interference, such as that emitted by loudspeakers, zips or electronic devices. Whilst this modernisation is not visible, it does improve the conditions for stable timekeeping in everyday use.

Another difference from the 1968 model is evident in the case back. Whilst the historic original concealed its mechanics behind a solid steel case back, the reissue offers a view of the Calibre 1150. The focal point is the skeletonised rotor in 18-carat gold, which winds the movement automatically.

A modern take

With a diameter of 37.4 millimetres, the new Bathyscaphe remains pleasingly close to the proportions of its historic predecessor, without being technically stuck in the past – quite the opposite: The Calibre 1150 offers a 100-hour power reserve, a silicon balance spring and, thanks to the sapphire crystal caseback, an unobstructed view of the 18-carat gold rotor. At the same time, the watch remains water-resistant to 300 metres – even if the chocolate-brown calfskin strap shifts its character more towards that of an elegant everyday companion than an uncompromising diving instrument.

The Blancpain Fifty Fathoms Bathyscaphe Ref. 5903 1110 63A is limited to 300 pieces. It is priced at 13,800 Swiss francs and comes with a five-year warranty. As such, it is less a nostalgic replica than a deliberately luxurious reinterpretation: compact, technically up-to-date and remarkably faithful to the look of the 1968 Bathyscaphe.

blancpain.com

Featured Image: © Tim Vaux