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Diver
fault is responsible for an estimated
99% of all out of air events. Distraction,
overloading and miscalculation are the
main three causes of out-of-air incidents.
Distraction is perhaps the
major cause of out-of-air events. In
fact, it is considered as a deadly killer
because it catches the diver by surprise
and increases the risk of panic. Divers
often become fascinated by the beautiful
undersea world, lose track of time and
simply forget to look at their tank
pressure.
Overloading
is a less frequent cause of out-of-air
incidents. Excess equipment, accessories
or a bulky underwater camera housing
can be a start. In addition, divers
can encounter heavy objects they try
to drag to the dive boat or the beach.
These collectibles include such items
as: lost weight belt(s), or a lost anchor!
Additional weight and excess drag can
burn up air/gas supply in half the normal
time.
Miscalculation
in my personal opinion is the greatest
cause of out-of-air events. It is virtually
impossible for a diver to precisely
plan a dive he/she has never made before.
He/she may encounter strong currents,
go deeper than intended, have an over-weighted
belt, or fail to take the shortest way
back. Any combination of these factors
can contribute to a miscalculation of
air consumption and therefore result
in the sudden termination of the dive
plan.
When
a diver runs out of air, he/she has
a margin of approximately 15-20 seconds
to check equipment, (in case of a false
alarm), make an accurate evaluation
of the situation, and finally make the
appropriate decision.
Controlled
Emergency Swimming Ascent. This will
not allow the luxury of a safety stop
or a required decompression stop. So
if you are not thrilled by the idea
of a solo ascent from deeper depths,
you should take all necessary measures
to prevent running out-of-air.
Most
experts agree that the chances of screw-ups
are dramatically reduced if you can
solve a problem yourself. However, CESA
is one of the most controversial self
rescue methods used today. The inherent
risk of air embolism puts the method
in hot debate. Therefore, many modifications
have been introduced to the method over
the years.
Today
divers are taught to retain the regulator
in the mouth while swimming slowly upwards
towards the surface. It is my personal
opinion that it is desirable to make
a direct ascent to the surface under
your own power, keeping the regulator
in your mouth and continuously exhaling
slowly. Students are always astonished
how long they can slowly exhale even
when saying a continuous ‘Aaaaah’,
sound all the way up to the surface.
I
often tell my students during the exercise
briefing that each one of them would
feel he/she is one of the greatest opera
sopranos of the world! In addition,
you will probably get a couple of breaths
on the way up as the ambient pressure
on the hoses is reduced during the ascent.
Although
most training agencies today agree that
the advantages of CESA far outweigh
the risks, most divers are so well conditioned
to seek help from their buddy underwater
even if they run out of air even and
are only a few meters deep! The obvious
solution never occurs to them.
Independent
Backup Reserves. The use of
pony bottles or a ‘Spare Air’
are perhaps a safer, more dependable
alternative since they allow you to
make an entirely independent self rescue.
The disadvantages can be summarized
in three main points:
 They
are expensive, bulky and add extra weight
to your scuba gear. In addition, out-of-air
situations will happen only when you
do not carry them along in your dives,
Murphy's Law!
Octopus
Ascent is today considered the most
desirable option for air sharing in
any out-of-air situation. It is a quick,
simple and easy method of sharing air
with your dive buddy while making a
normal ascent to the surface. However,
octopus ascents require the help of
a dive buddy who not only has to be
within reach in the proper time, but
also has sufficient air supply to support
the two divers.
Buddy
Breathing is so far down in the list
of preferences that it has been relegated
to a vanishing art. However, given no
other alternatives, it can get you back
to the surface if both divers are skilled
in its practice. Unfortunately, the
record of double fatalities for divers
engaged in buddy breathing is relatively
high. The reality is that the skill
is difficult to master for most student
divers and then quickly lost unless
practiced often in the field.
Buoyant
Ascent is probably the most uncommon
and most forgotten way of self rescue,
often ignored when should be done and
unfortunately practiced when it should
not! Although it is not intended here
to go into the details of the technique,
it is clear that alot of training and
practice are the only way to master
such a skill. One can summarize the
technique as follows:
Taking off the weight belt at depth
allows a quick start of the ascent,
letting the expanding air out from your
BCD and flaring your body to a horizontal
position are two ways to slow done the
ascent rate as needed. Looking up to
see the water surface (if you are in
the clear Red Sea), and exhaling all
the way up are ways to prevent lung
overexpansion.
Which
method is best to cope with an out-of-air
situation? Honestly, there is no such
thing as the "best method"
for self rescue. Each has been time
tested and proven to save lives. Each
offer advantages under certain circumstances.
The
important issue is that every diver
should be responsible, and take all
measures to prevent an out-of-air incident.
Nevertheless, every diver should be
fully trained and proficient in all
self rescue methods available.
We
should not argue about the theoretical
advantages of one method over another,
this would not help solving the problem
when it comes. I believe that the more
you know the better chances you have.
If you did not obtain training (during
your basic class) in all available methods
of self rescue, you better learn about
them now. This is especially true if
you are not aware of the latest techniques
of my personal favourite one: Controlled
Emergency Swimming Ascent (CESA). Remember
that you can achieve safety through
education. So when you are down there
facing a situation, take a second to
work out the "best method".
Safe diving. |
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