Technique preparation begins
with learning how to swim unequipped. Then comes diving. There are two
main types of going under water – breath-hold diving and scuba diving.
The former is performed with the following pieces of equipment (known as
"set number one"): a diving mask, fins, a snorkel, a neoprene suit, a ballast
belt, a depth-meter, etc.; the latter (performed with "set number two")
includes all of the above plus a breathing apparatus.
Techniques Performed with Set Number
One
There are three main ways
of going under water when diving with set number one. These are the following:
Feet-First Submerging
It is performed relatively
easy. At first, the diver takes 6 to 10 deep breaths. Then with rowing
circular hand movements from the hips upwards. It is very important to
be well-balanced because if the diver is not, submerging takes additional
efforts.
Head-First Submerging
It begins with 6 to 10 deep
breaths through the snorkel. The arms are stretched in front of the head.
Then, with a jerky folding at the waist, the torso and the head become
almost vertical. The feet are still on the surface. Then, with a powerful
motion the legs straighten up vertically and the body sinks without any
effort. When the fins submerge, the diver starts moving his legs quickly.
Jumping in the Water
This is the way one enters
the water from board the ship or the brim of a pool. The diver stays at
the edge and, facing the water, he pushes the mask with one hand and with
the other supports the snorkel. The head is slightly bent forwards. From
this starting position the diver jumps into the water and enters feet-first,
then he gets to the surface and signals with a hand.
This way of entering is very dangerous when jumping from rocks into unfamiliar
waters.
Underwater Techniques
When diving, the first problem
that a free diver encounters is the need of equalizing the pressure in
his middle ear because of its anatomo-physiological features. This can
be done in several ways:
-
by swallowing
-
by chewing
-
by blowing – the nose is pushed
through the jack of the mask with the thumb and the forefinger and then
the diver tries to exhale through it with his mouth closed.
A beginner cannot easily equalize
the pressure because his Eustachian tubes are not passable enough. In order
to equalizepressure with less effort, the diver should fill his ears by
shaking his head in water before submerging. Another useful hint is to
start equalization in the first and second meters. If the equalization
is impossible, the diver should get out of the water.
When under water the diving
mask often fills with water. In order to clean it, the diver should bend
his head backwards in such position that the glass of the mask should be
almost parallel to the surface, then with four of his fingers (without
the thumb) the upper edge of the mask is pushed towards the face. Powerful
exhaling through the nose clears away the water. When the mask gets damp,
water is used to wash it.
Techniques Performed with Set Number
Two
Before entering the water,
set number two should be checked for any faults. The pressure in the breathing
apparatus is measured with a high pressure manometer in the following way:
-
the manometer is screwed on
the apparatus
-
the exhaust valve of the manometer
is closed
-
the of the apparatus is
also closed
-
the exhaust valve of the manometer
is opened
-
the manometer is taken off the
apparatus
The pressure is measured when
the of the spare air is opened. The check whether the apparatus is
air-proof is done by listening to a noise of flowing air when the cocks
are open. The good working order of the heaver of the spare air is also
checked by opening and closing it. The functioning of the apparatus is
checked by inhaling several times. Special attention is paid to the smell
and taste of air. Let us now mention the main techniques performed using
set number two:
 Jumping
Facing the Water
It is performed in the same
way as with set number one but here one of the hands holds the strap of
the apparatus.
Jumping Back-First
One of the hands holds the
mask and the mouthpiece and the other holds the strap of the apparatus.
The body rests backwards and in the last moment it jumps away from the
boat or the edge of the pool. The surface of the water is first met by
the lower part of the apparatus and the pelvis.
Descending Down the Stairs on the Side of a
Ship or a Pool
Going down or climbing are
done only with one's back towards the water, in order to avoid falling
in it. There should be no-one under the stairs because if the descender
falls down, an accident might occur.
Entering the Water From the Side of a Boat
It is performed when the
diver sits on the edge, his back towards the water, and rolls over the
deck falling in the water on his bottles.
Entering Over the Deck by a Stay on the Knee
or the Leg
Entering From the Shore
It is done by walking backwards.
When the depth becomes 1 meter, the diver begins swimming.
Clearing the Water from the Breathing
Hose
Water
penetrates the hoses at every voluntary or involuntary taking out of the
mouthpiece under water. It is relatively easy to clear the water away.  The
mouthpiece should be lifted above the head, and as a result of the artificially-created
difference in pressure between the membrane of the pressure regulator and
the mouthpiece, the apparatus begins to release air. Air itself flows through
the breathing hoses and replaces the water. Thus, with a powerful blow
of exhaled air, the water from the exhaling hose is cleared away. In order
to prevent water from re-entering the hoses, when the mouthpiece is put
in the mouth, the difference in pressure should be kept. The latter is
obtained by bending the body and the head backwards and biting the mouthpiece
while air is flowing through it.
Two Divers Breathing from a Single
Apparatus
 This
is done in the following way: Diver A, whose apparatus is going to be used
for breathing, lifts Diver B with one hand and puts the mouthpiece with
flowing air in Diver B’s mouth. Diver B takes a few deep breaths. Then,
Diver A slightly shakes the mouthpiece warning Diver B that he is going
to take it out. Diver A bends his body and head backwards, puts the mouthpiece
in his mouth and takes a few deep breaths.
Every single diver must learn how to do the breathing as Diver A and as
Diver B. Diver A is the leading one and he or she observes whether the
decompression tables are being followed.
Taking off the Breathing Apparatus
under Water
 This
procedure is performed when a diver swims through narrow passages. The
diver unfastens the belts and the straps of the apparatus and bends forward.
Then, he takes off the apparatus over his shoulders without stopping to
breathe. The apparatus is then carried in front of the body with straightened
arms at the level of the mouth.
Balance
Balance is essential for
the diver. When a body is in water, two forces occur – the force of the
own weight and the elevating force. The ratio between these two determines
whether the body will sink, stay on the surface or have a neutral buoyancy.
The latter is the best option. It is achieved when a fully-equipped diver
lies on the surface and puts different weights on his stomach until the
moment when he does not sink with full lungs but sinks with deflated lungs.
Read more on that in the Physics Section. |
