Bühlmann Watches Blog

Swiss horology meets Swiss dive science in the new Bühlmann Decompression 02

2025-12-05 17:34
The foundations of modern dive safety were laid by Prof. Albert A. Bühlmann, whose pioneering research from the late 1950s to the 1980s resulted in the ZH-L16 decompression algorithm, a model still employed by most dive computers and tables today. Bühlmann’s work was revolutionary for its completeness, as it addressed decompression at sea level and at altitude, thereby creating a model applicable to the full range of diving environments.
Better, Bolder and Safer than its precursor, the Bühlmann Decompression 02 is the functional and usability evolution of the widely acclaimed Decompression 01 first introduced in 2021. It is the first mechanical dive watch to feature a twin safety diving bezel and a twin decompression stops dial to safely manage decompression stops for dives in the “Golden Zone”.

Bolder

The Decompression 02 has been imagined as a professional mechanical dive watch that can be used as a backup to a digital dive computer. It has been built the way it had to be built, with no concessions to established dive watch design conventions.
The Decompression 02 incorporates the ZH-L16 decompression algorithm and has been conceived in collaboration with professional divers. Furthermore, it has been functionally validated by decompression science specialists, including former members of the Bühlmann research team, the Divers Alert Network (DAN) Europe and the World Underwater Federation Switzerland (CMAS Switzerland).
As a young engineer and an enthusiastic diving instructor, deeply interested in decompression research, it has been an outstanding experience to work with Dr. Bühlmann as a research associate, a programmer and a test diver. The Bühlmann Decompression 02 is a marvellous piece of micro-machinery and Swiss precision. It reflects in noble form Prof. Bühlmann’s endeavour to enhance the safety of all divers worldwide, now and in the future.
Beat A. Müller, MSc Mech. Eng. ETH and former member of the Bühlmann Research Team at the University Hospital of Zürich

​Better

The watch introduces several innovative features. It’s the first dive watch to feature the Bühlmann Twin Safety Bezel®, a twin diving bezel that enables the separate tracking of the total dive time (TDT) and decompression stops (DS), each with its own fail safe blocking direction.
The decompression stop times for the 17 dive profiles featured on the Bühlmann Twin Dive Dial® are derived from Dr. A. Bühlmann’s renown dive tables which still, after 40 years, remain among the most widely used and widely adopted by the diving industry, including in dive computers.
My father always believed that science should serve safety. I am proud to witness his groundbreaking work embodied in this exquisite mechanical instrument — and supporting DAN Europe’s research — a true continuation of his life’s mission.”
My father always believed that science should serve safety. I am proud to witness his groundbreaking work embodied in this exquisite mechanical instrument — and supporting DAN Europe’s research — a true continuation of his life’s mission.
Thomas Bühlmann, board member Bühlmann Dive Watches

​Safer

Plan, Dive, Manage: The Bühlmann accompanies the diver in every phase of a dive and after a dive.
How? Firstly, the diver establishes the dive profile in terms of maximum dive depth, the time spent at that depth and the bottom time (BT). This profile is then set on the watch by turning the right crown — the profile data and the related decompression stops time will appear in the opening at 6 o’clock.
Next, the total dive time bezel (inner bezel) is set to 0 by putting the 0 marker in correspondence with the minutes hand before starting the dive. Once the bottom depth is reached, the Diver can follow the chosen dive profile in terms of bottom time on the total dive time scale. When it is time to resurface, the maximum rate of ascent is measured using the seconds hand and the decompression stops at 9m,6m and 3m depth are measured by using the outer decompression time bezel.

At the end of the dive, the diver will turn the bottom dial to the “Fly-no-Fly” position and set the indicator to “No-fly”. It will be safe to fly once the arrow points to the green zone.
For what regards the available dive profiles, the Decompression 02 focuses on the “Golden Zone” dive profiles — these are the 17 most common dive profiles for single-tank dives up to 39 meters depth (for dives at altitudes from 0 to 700m ASL). The twin dial construction allows divers to view decompression data through a rotating lower dial, operated mechanically with the crown positioned on the rigth.
The Decompression 02 was designed to complement dive computers, not to compete with them. It’s the mechanical expression of scientific rigour and a limited edition collectible which embodies true Swiss craftsmanship. We built it the way it had to be built: with no concessions to established dive watch design conventions.
The Decompression 02 was designed to complement dive computers, not to compete with them. It’s the mechanical expression of scientific rigour and a limited edition collectible which embodies true Swiss craftsmanship. We built it the way it had to be built: with no concessions to established dive watch design conventions. Guido Benedini, CEO, Bühlmann Watches

Honouring a common Legacy: DAN Europe Research and Bühlmann Dive Watches.

The Bühlmann Decompression 02 is at the source of a the partnership between DAN Europe and Bühlmann Watches. It represents a shared long term commitment to advancing dive safety through science. At its core is a mutual belief in the power of research to save lives and in the importance of honouring the pioneers who laid the groundwork. Bühlmann Watches will associate the DAN Europe Medical Research Fund and raise awareness about its quest to develop the perfect decompression algorithm, an algorithm which takes the individual diver’s characteristics (sex, weight, age etc.) into account. The legacy of Dr. A. Bühlmann, whose decompression tables remain the global standard, will be used to promote DAN Europe’s ongoing research and educational mission.
Working with Prof. Bühlmann was instrumental in shaping the early stages of my career. At DAN Europe, I am pursuing that mission alongside our research and medical team, evolving universal algorithms into personalised decompression strategies. This watch honours that legacy while supporting vital research that is shaping the future of dive safety. Prof. Alessandro Marroni, Founder and President, DAN Europe
A portion of each Buhlmann Decompression 02 watch sale will be donated to the DAN Europe Medical Research Fund. DAN Europe members will be able to access an exclusive execution of the watch, featuring the DAN Europe logo, reinforcing their role as ambassadors of safety. This edition is part of the total 575 pieces limited edition.
This partnership is a tangible way for divers to contribute to the future of their sport. By wearing the Bühlmann Decompression 02, they signal their commitment to science, legacy, and the pursuit of safer diving for all.

Technical Features

The 48.50 mm stainless steel Decompression 02 with ceramic bezel is powered by a slim Swiss made Sellita SW300 mechanical automatic movement and has a sapphire crystal.
The other notable features are:
  • Legacy-based design and usability: Inspired by Bühlmann’s original circular decompression calculator with “Golden Zone” logic: 17 most frequent dive profiles and a “fly-no-fly” segment
  • Twin Safety Bezel®: Two counterrotating bezels for total dive time (clockwise block) and deco time (counterclockwise block)
  • Twin Decompression Dial®: Two dials with a rotating sub-dial featuring the ZH-L16 decompression data, visible through a sapphire opening
  • XXL minute hand: Enhanced readability for timing decompression stops, total dive time and ​bottom time
  • Minimalist hour hand: Keeps visual focus on the minutes hand and the dive and decompression timing
  • 5° case inclination: Improves dial legibility
  • Helium valve: to prevent damaging the watch after prolonged stays in mixed gas pressurised atmospheres
  • Flexible strap joint: Adapts the watch to all wrist sizes for maximum fit and comfort
  • Detachable Strap extension: providing the extra length to wear the watch over your wetsuit
  • Concave case back: for extra wear comfort
  • 575m water-resistance: a depth that matches Bühlmann’s own hyperbaric record and the necessary water-resistance with a sufficient safety margin for diving in the “Golden Zone”
  • Special dive box: a unqiue box for that special gift and a practical box to travel with the watch
  • Swiss made: a guarantee of horological quality, manufacturing standards and manufacturing sustainability

Prices and edition

The Bühlmann Decompression 02 with the signature “Druckkammer Blue” dial celebrating Dr. A. Bühlmann’s legacy will be manufactured in a limited edition of only 575 pieces.
Recommended retail price is CHF 3'990.00 (until 31.03.2026 the pre-sale price of CHF 3'790 applies).
About DAN Europe
DAN Europe (Divers Alert Network Europe) is an international non-profit medical and research organisation dedicated to diver health and safety. Since 1983, DAN Europe has offered medical assistance, scientific research, education, and safety initiatives, while also advocating for environmental responsibility and sustainable diving practices.
About Bühlmann Watches
Bühlmann Watches is a Swiss independent watch brand dedicated to translating the scientific legacy of Dr. Albert A. Bühlmann into mechanical timepieces of purpose. Inspired by the pioneering decompression research conducted at the University Hospital of Zurich, Bühlmann develops watches that integrate real-world diving functionality into precise Swiss watchmaking.

Created in collaboration with divers, researchers, and institutions such as DAN Europe and CMAS Switzerland, Bühlmann timepieces are conceived as reliable instruments—designed to support decision-making in critical moments while remaining refined objects of enduring value.

Produced in limited quantities, each Bühlmann watch reflects a commitment to scientific integrity, functional clarity, and understated Swiss design.

Founded in 2020 Bühlmann Watches is a company of Thomas Bühlmann and GFF Suisse SA (Watch Angels) and is based in the historic watchmakers village of Arogno in Switzerland.
Learn more about the Bühlmann Decompression 02