Water Resistance & Watches

So what does DNV GL (formerly Germanischer Lloyd) have to do with a watch manufacturer from
Frankfurt am Main? The renowned company tests and certifies our diving watches according to a variety
of criteria. One test focuses on water resistance and pressure resistance, while a second test procedure
covers something never done before in the watchmaking industry: certification in accordance with the
European standards for diving equipment!

The background: time plays a crucial role in survival on every dive. Diving watches must therefore
be water-resistant, reliable and durable, and guarantee perfect readability in all lighting and water
conditions. The information we provide about our diving watches is thus not merely captured in words,
but proven in practice as well.

Testing for water resistance and pressure resistance
Since 2005, DNV GL has been testing our diving watches for water resistance and pressure resistance.
In accordance with these certification standards, the 206 ARKTIS II and 206 St Ar are pressure-resistant
to 30 bar, the EZM 3 and EZM13 are pressure-resistant to 50 bar, the T1, U1, U212 and the U1000 series are
pressure-resistant to 100 bar, while the T2, U2 and U200 series are pressure-resistant to 200 bar and the UX
series is actually pressure-resistant to any accessible diving depth. For this series, DNV GL has confirmed
the pressure resistance of the case to 12,000 m and of the movement to 5,000 m diving depth. The tests
are repeated at regular intervals on all of these watches in order to document the consistency of the
quality.

Premiere: certification for compliance with European diving equipment standards
In a standardised test situation, will a diving watch deliver the same reliable performance as, say, a
breathing apparatus? To answer this question, we were the first who have watches tested and officially
certified according to the European standards for diving equipment. Also these tests are performed at
regular intervals for all these watches. The testing and certification according to the European standards
EN250 and EN14143 was completely new territory for both sides. This was the case because the standards for
diving equipment cannot be applied to watches without modification. The experts at DNV GL thus adapted
the standards appropriately and defined two series of tests. In the first of the two, they put the timepieces in a
test cabinet for three hours at –20°C, then for three more hours at +50°C. The timepieces were subsequently
checked for accuracy and functional reliability at both temperatures. In a second test, the watches had to
withstand three hours at –30°C and 3 hours at +70°C with 95% humidity.

The result
Temperature resistance and perfect functioning were documented and certified for the watches in the U1,
U1000 (since 2007), U2, U200 (since 2009), T1, T2, U212 (since 2013), EZM 13 (since 2014), 206 (since 2019) and
EZM 3 series after both tests. The UX series watches were also certified; however, these were subjected to a
modified test involving temperatures between –20°C and +60°C due to their battery operation and oil filling.

With over 150 years of instrument and watchmaking heritage, centred on the nautical industry, it’s easy to understand why Muehle-Glashuette has cornered the market on watches designed to withstand even the harshest aquatic conditions. Their special Mission Timers, designed for and used by the German North Sea Search and Rescue team, deliver the quality you can rely on as well as precision timekeeping in extreme conditions and everyday wear.

Special features such as 4mm thick glass on the iconic SAR watch give it strength to persist pressure up to 100 bar (1000m)

The SAR Pilot Chronograph has the pushers and crown on the left for freedom of wrist movement and easy manipulation when wearing diving gloves

The Sea Timer Black Motion boasts 300m water resistance, and an offset crown for added protection. The specially designed canvas band has a silicone backing making it water safe and comfortable.

The Seebataillon GMT also gives 300m water resistance, a turning bezel, high luminosity and a sturdy silicone band with adjusting lug adapters – it’s good enough for the German Navy!

The Rasmus collection of diving watches look great, function well and will withstand up to 2000m water resistance (200bar)

Muehle-Glashuette Cooperation with the Maritime Rescue Workers
The story of the S.A.R. Rescue-Timer

The German Maritime Search and Rescue Service (DGzRS) has been keeping sailors safe on the North Sea and Baltic Sea for more than 150 years. Its maritime rescue teams are responsible for tackling important and often dangerous missions that help to save multitudes of lives. Even since it was first founded, the DGzRS, which is financed solely by donations, has saved nearly 85,000 sailors in distress.

The founding of the service was preceded by several severe shipwrecks on the North Sea Coast, after which there were calls for German search and rescue activities to be placed under the umbrella of one organisation. This initially led to the establishment of regional search and rescue associations, which came together to form the German Maritime Search and Rescue Service in the German city of Kiel on 29th May 1865. When Robert Mühle founded our family company in Glashütte, the DGzRS had already existed for several years.

The sea rescue crews and Mühle-Glashütte have shared a common tradition since February 2002, the year in which the first S.A.R. Rescue Timers were handed over to the leading rescuers
of the DGzRS. The watch was developed in cooperation with the sea rescuers and is geared to the harsh conditions at sea. The S.A.R. Rescue-Timer is therefore an essential time-measuring instrument for the crews on their rescue missions. When out at night, the crews often turn off the lighting and even the instruments in their rescue boats in order to achieve better visibility of the sea. The fact that the S.A.R. Rescue-Timer also offers excellent readability at night means that the rescue teams can still keep a precise record of timings for mission reports in such conditions. As a watch brand with a nautical background, Mühle-Glashütte was the ideal partner for cooperation with the maritime rescue workers, whose missions often take them out into rough waters. Although their rescue cruisers have always been highly seaworthy, the rescuers’ own personal watches were often damaged on rescue missions. In March 2001, we contacted the maritime rescue teams and proposed the development of a user-based watch that could master the tough conditions involved in their work.