X-Fathoms: the ultimate diving watch

In 2012 Blancpain translated the heritage of the first professional diving watch into unprecedented mechanical depth with the X-Fathoms, reference 5018-1230-64A. Let’s take a closer look at this masterpiece.


This report replaces the one I did a few years back and which was listed as one of the first posts in this blog, it contains more information and updated photos.

More an instrument than a watch

The X-Fathoms is really not an every day timepiece like the Fifty Fathoms or the Bathyscaphe. The concept behind the X-Fathoms is to achieve what no mechanical diving watch has done before: combine water resistance, legibility, antimagnetic protection, luminescence and robustness to a level that can be understood as the a new peak in the tradition of professional instruments.

The 55.65mm titanium case has no lugs in the conventional way, it actually merges with a well thought through rubber strap. The unidirectional sapphire bezel bears the typical Fifty Fathoms design, while the dial uses the traditional hour markers known from the so-called military dials in the Leman collection, combined with a plentiful of color coded dive information. Here’s a legend about the indications, courtesy Blancpain:


Now, how is that information derived technically? The key to it is found in the case flanks and back: water runs through a sealed part of the case meeting a membrane made of patented liquid metal, an amorphous metal alloy made of zirconium and four other metals, exclusive to Blancpain for use in their diving watches.

The deformation of the membrane is translated to the depth reading through a rack and pinion system. To achieve maximum accuracy, all components are made to tolerances that exceed even the highest standards in high horology, using innovative and ultra precise methods like X-ray lithography. This results in an accuracy of 30cm at a depth of 15m, a never before realized precision in a mechanical diving watch.

The X-Fathoms allows depth measurement up to 90 meters. To provide the information in the most useful way, Blancpain decided to go the extra mile and offer two scales on the dial with two different hands: 0-90m and 0-15m with 50cm graduations.


In addition a third depth hand indicates the maximum achieved depth during a dive, which can be reset through a protected pusher at the 8 o‘clock position.

Furthermore the X-Fathoms features a 5 minute countdown timer for measuring the decompression at the 10 o‘clock position.

The timepiece is powered by calibre 1315 with a silicon hairspring to protect it from magnetization. The movement is obviously sealed from the water exposed membrane system.

A giant very comfortable to wear

Despite its size, the X-Fathoms sits very comfortably on my rather small wrist due to the exceptional rubber strap. It actually fits like a glove, supported by a double pin buckle that took its inspiration from the form of a manta ray. The watch will not fit under any cuff, with the rightful place for the X-Fathoms being on top of a diving suit anyway.

The icing on the cake is the luminescence of the X-Fathoms. This is without any doubt the most impressive lume I personally have ever encountered, but judge for yourself:


You find the X-Fathoms here on the Blancpain website. An in depth technical explanation can be found in the Lettres du Brassus No. 11, written by Jeffrey S. Kingston, providing a lot more insight than this report. Your understanding of the functionality of the X-Fathoms will be further enhanced by reading the deconstruction done by Peter Speake-Marin, which can be found here in the blog. And finally, here you can see the X-Fathoms in action used by two fellow enthusiasts .

I hope you enjoyed the report and the photos!



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