BÜHLMANN Decompression 01 User manual

USER MANUAL BUEHLMANN DECOMPRESSION 01
Your Bühlmann Decompression 01 is a watch for demanding sportsmen and -
women. Please read this user manual to get acquainted with the functioning of your
watch and take note of all disclaimers, caution items and security recommendations.
Disclaimer
Whilst the Bühlmann Decompression 01 is a diver watch according to traditional
watchmaking industry standards, it is not a dive computer nor a professional diving
watch according to ISO or any other official - private or public - certification agency
or institution. It should UNDER NO CIRCUMSTANCE be used as the only diving
instrument or to replace a dive computer. It should also UNDER NO
CIRCUMSTANCE be used as the only diving instrument for managing diving at
altitude over 700m above sea level and to decide whether to fly or not to fly after a
dive.
Diving is an inherently dangerous sport and exposes one-self to the risk of
permanent injury and/or death. GFF Suisse SA t/a Watch Angels and Cronatec LLC
will not accept any liability for injury or death caused whilst engaging directly or
indirectly in any diving activities with the use of the Bühlmann Decompression 01
watch.
There are no warranties or guarantees, either expressed or implied that the
information contained in this user manual or our website www.watchangels.ch site is
accurate, correct, updated or reliable.
You are responsible for using your own good judgement. You should be in good
physical condition, enjoying good health, have a certification from a recognized
training organization and sufficient knowledge to participate in every dive. Your level
of fitness and experience is an essential requirement for your dive plans. You should
dive within your limits at all times, protect yourself from natures elements and stay
hydrated to maintain your physical condition.
Caution 01: Use a diving computer
Despite being, horologically speaking a professional diving watch, the Bühlmann
Decompression 01 should never replace a professional diving computer. Only dive
computers collect and calculate all the elements you need for secure diving. The
main goal of the Bühlmann Decompression 01 watch is therefore to help the diver
understand and apply the modern security instruments for free diving and UNDER
NO CIRCUMSTANCE to replace or being used as a diving computer.

Caution 02: No dive without serious planning
Planning your dive is essential for your personal security. Depending on the way you
are breathing, on the air pressure in your air tank, on temperature, currents etc. you
will develop a sound feeling how long your dive trip can last. From this complete
cycle you must deduct your way down to the ground, the bottom time, the ascent
time and all the security stops you find on the bezel for the maximum depth of your
dive excursion.
Let’s make an example:
You want to go down to a maximum depth of 40 m. Your experience tells you that
normally your air reserve lasts for 40 minutes. Always keep a reserve! Descent will
take let’s say 6 minutes. The ascent control on the watch indicates that you cannot
ascend faster than 10m per minute. So, coming up takes another 4 minutes. The
three necessary security stops for a 40 m dive will sum up 55 minutes. This of
course cannot work. The total necessary time by summing the necessary steps is of
65 minutes and your air reserve is of 40min. Consequently, you must replan your
adventure completely, organize a bigger air reserve and a secure ascent to enjoy a
reasonable bottom time.
Caution 03: Screw down the crowns
The main cause of damaged dive watches is water entering the watch and damaging
the movement. To avoid this risk, you must screw down all the three crowns of your
Bühlmann Decompression 01 tightly before entering the water and lock them with
the bezel push-lock system. Never open a crown once you are under water!
Only the decompression bezel can be turned during a dive. As a security measure
the decompression bezel only turns clockwise. This means that, for your safety, it
can only extend but never shorten your security stops.
The Bühlmann Decompression 01 is a self-winding automatic mechanical watch. For
precautionary reasons, even if an automatic watch winds under-water, be sure not to
stay near to the end of its power reserve when you start diving by rewinding the
watch before every dive.
1. DECOMPRESSION STOPS TURNING BEZEL
Why a decompression stops turning bezel?
Decompression tables allow divers to plan the depth and duration for dives and the
required decompression stops. On your Bühlmann Decompression 01 watch the
decompression table is executed as a circular calculator.
The information on the bezels for 20, 30 and 40m is taken from Bühlmann's 1974
calculation disk. Since there is limited space for data on the watch, the

decompression data on the bezels for 20, 30 and 40m are only given for the longest
possible bottom times of the Bühlmann decompression calculation disk.
Attention! The breathing gas will therefore most likely not be sufficient for a dive
with this bottom time
1.1 Description of the information on your watch (Fig. 1)

Example valid for the depicted 40m bezel
(a) Luminous dot at 12 o’clock (same for all bezels)
Once the minutes hand aligns with this dot when you are measuring your
decompression stop time, it means your decompression time has been reached and
you can proceed to the next decompression stop.
(b) Depth 40 m
This indication helps you to identify the correct bezel for your planned dive. For
example, if you decide to dive to 40m you will mount the 40m decompression bezel
on your watch.
(c) BT 40 min
BT stands for bottom time. If you dive to 40m the maximum bottom time (meaning
your planned work time on the ground) is 40 minutes. All security stops are
calculated with this long stay at 40 m deep.
(d) RG K, L (same for all bezels)
If you do repetitive dives over a limited period, your body will be saturated with
additional gas for each dive. With each further dive it is therefore necessary to
calculate longer safety stops. Repetitive groups (designated with capital letters) are
used for this purpose. The repetitive groups K and L result in the longest time
surcharges. As a result, on your bezel you have the longest security stops previewed
by the original 1974 Bühlmann calculation disk.
(e) 0-700 m ASL (same for all bezels)
This indication stands for 0-700 m altitude above sea level. On the Bühlmann
watches we calculate with decompression stops on sea level or not higher than 700
m. Attention: if you dive in higher altitudes like mountain lakes, you cannot use the
bezels of the watch but must use specialized decompression tables which calculate
longer security stops.
(f) Security decompression stops 1 (9m), 2 (6m), 3(3m)
These number shows you the sequence of the decompression stops, 1 is the first, 2
the second and 3 the third stop. Left of the number you see the depth of the stop.
The number below the depth in meters shows you the total time of stand still at the
indicated depth in minutes: 5 minutes at 9m, 15min at 6m and 35min at 3m.
1.2 How to use the decompression turning bezel
Your Bühlmann Decompression 01 comes with three exchangeable decompression
bezels for dives at 20, 30 and 40m. They can be exchanged by unscrewing the 4

screws on the side of the bezel using the provided screwdriver. Do not use any other
screwdrivers to avoid the risk of damaging the screws.
Each bezel should ONLY be used for a dive at the specified depth (or shallower)
indicated on the bezel (a.) and at sea level or at maximum 700m above sea level
(b.) If you use a bezel specified for a specific depth for a dive to deeper depth, the
information will be wrong and if it is used for managing a dive this could lead to
permanent injury or death.
Attention!
Before each dive, check that you have mounted the correct bezel for the dive.
To calculate your decompression stops on a dive you must stop at EACH
decompression stop indicated on the bezel and, at each stop, bring the
corresponding depth/time marker in front of the minutes hand by turning the bezel.
You then must stay at the given depth until the minute hand reaches the luminous
dot on the bezel. When the minute hand reaches the luminous dot, you can then
proceed to the next decompression stop and at repeat the same process.
Example 1: dive to 40m (Fig. 2)
The 40m bezel shows a MAXIMUM bottom time of 40min and three security stops.
1) Choose the 40m bezel and fix it to your watch
2) You will see on the bezel that there are 3 decompression stops markers for
such dive: 1 = -9m (5min); 2 = -6m (15min) and 3 = -3m (35min)
3) When you reach stop 1 on your ascent, you stop and set the -9m/5min
decompression stop marker (b) on the bezel in front of the minutes hand by
turning the bezel. The 5 minutes will have elapsed when the minute hand
aligns with the luminous dot on the bezel (a). Only then you can proceed to
the next stop
4) When you reach stop 2 and 3, repeat the same process, using
decompression stop markers (c) and (d)

Example 2: dive to 30m (Fig. 3)
The 30m bezel shows a MAXIMUM bottom time of 75 minutes and three security
stops.
1) Choose the 30m bezel and fix it to your watch
2) You will see on the bezel that there are 3 decompression stops markers for
such dive: 1 = -9m (7min); 2= -6m (15min) and 3 = -3m (42 min)
3) When you reach stop 1 on your ascent, you stop and set the -9m/7min
decompression stop marker (b) on the bezel in front of the minutes hand by
turning the bezel. The 7 minutes will have elapsed when the minute hand
aligns with the luminous dot on the bezel (a). Only then you can proceed to
the next decompression stop
4) When you reach stop 2 and 3, repeat the same process, using
decompression stop markers (c) and (d)

Example 3: dive to 20m (Fig.4)
The 20m bezel shows a MAXIMUM bottom time of 105 minutes and two security
stops.
1) Choose the 20m bezel and fix it to your watch
2) You will see on the bezel that there are 2 decompression stops markers for
such dive: 1 = -6m (3min) and 2= -3m (31min)
3) When you reach stop 1 on your ascent, you stop and set the -6m/3min
decompression stop marker (b) on the bezel in front of the minutes hand by
turning the bezel. The 3 minutes will have elapsed when the minute hand
aligns with the luminous dot on the bezel (a). Only then you can proceed to
the next decompression stop
4) When you reach stop 2, repeat the same process, using decompression stop
marker (c)

2. THE ACUAL DIVE TIME (ADT) INDICATOR
Why the actual dive time indicator?
The actual dive time indicator measures our total elapsed dive time to make sure
that you do not exceed the maximum time you can stay underwater. Never stay
longer under water as your expected air reserve! If necessary, organize a spare air
tank. Actual dive time is measured with the aid of the internal turning bezel of the
watch.
How to use Actual Dive Time indicator (Fig. 5)
The actual dive time (ADT) can be calculated by using the inner turning bezel (a).
The inner turning bezel is operated by the crown on the top right (b) which is marked
with ADT.
To measure your ADT, you proceed as follows:
1) Before starting your dive, you place the triangle (c) on the inner turning bezel
in front of the minutes hand
2) During the dive you can at any moment read your ADT by reading the elapsed
time on the scale in front of the minutes hand
In the example on Fig. 5 the ADT is 20 minutes.
Attention do not operate crown b under water! This could cause the water-resistance
of your watch to be compromised and your security put in danger.