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There is a worrying trend
amongst some divers to reduce the amount of
decompression they do to the absolute minimum. Doing the minimum amount
of decompression possible is seen as a badge of honour. There are
several words which can be used to describe this mindset: crazy,
dangerous and irresponsible are just three that spring to mind.
This
mindset is fuelled by two factors. The first is the macho image that
some inexperienced tech divers believe is essential in order to appear
to be a real technical diver. This, of course, is rubbish.
The
most experienced technical divers are the least macho and the most
conservative. The second factor is the adherents of particular
decompression theories or methods who believe that their theory is so
accurate that there is really no need to be more conservative.
Anyone
that tells you that they completely understand decompression is either
very arrogant or very ignorant. The worlds leading decompression
theorists will admit that there are huge areas of decompression that we
still dont fully understand and yet there are divers who will insist
that they know exactly what is happening during their decompression.
Most
technical divers take the view that if they get to the surface without
neurological problems or a pain in the joint then their decompression
has been successful. They think that a bit of an itch is just an
indicator that they are getting close to their personal limits.
However, they may still be storing up long term problems that will not
immediately be apparent.
To me there is nothing wrong with
taking a conservative approach to decompression and doing a bit more
decompression then may be warranted. If, in ten years time, we find the
definitive theory of decompression then I would rather find out that I
have been doing slightly more decompression than is necessary then to
find out that I have been doing too little decompression.
There
is very little evidence for the long term effects of Trimix
decompression diving. Military and commercial divers have been diving
to similar depths using Heliox for many years but there is very little
knowledge of the long term impact of Trimix diving. We all
know the
immediate symptoms of decompression sickness but Hyperbaric Doctors
also know that there are long term problems associated with hyperbaric
situations. Brain lesions, retinal damage and bone damage are all known
symptoms of certain types of pressure exposure.
There are
exceptional times when we do want to cut our decompression as short as
possible, for example a flooded dry suit in freezing temperatures or
container ships bearing down on our position. For all the other times
there is no such rush. A few extra minutes of decompression will do no
harm.
I am quite happy if I find that Im the last one back on
the boat as Ive decided to do a few extra minutes of decompression.
The other divers may have eaten all the biscuits by the time I get back
on board but other than that there is no real disadvantage. On the
other hand coming up first may mean that, in years to come, those
divers that reduced their decompression to the minimum end up with
serious long term health problems.
The above article was written
by Mark Powell, one of only a few full
time Technical Instructors in the UK.
If you would like to discuss any aspects of Technical training with
Mark, please contact him direct on 07770 864327. |
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