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Normal procedures generally apply to diving in extremely cold environments.
However, the increased likelihood of regulator freeze-up calls for total familiarity
with the buddy breathing procedures described in Chapter 7. This section outlines
some of the precautions for operating in cold and ice-covered water.
General Precautions. General precautions for ice and cold water diving operations
include:
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Divers should be well rested, have a meal high in carbohydrates and protein,
and should not consume any alcohol. Alcohol dilates the blood vessels in the
skin, thus increasing body heat loss.
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Bathing is an important health measure to prevent infectious diseases prevalent
in cold environments. If necessary, the body can be sponge-bathed under
clothing.
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After bathing, a soothing ointment or lotion should be applied to the skin to
keep it soft and protect it against evaporation caused by the dry air.
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Shaving and washing the face should be done in the evening because shaving
removes protective oils from the skin. Shaving too close can also remove
some of the protective layer of the skin, promoting frostbite.
Dressing Precautions. With a properly fitting suit and all seals in place, the diver
can usually be kept warm and dry for short periods in even the coldest water.
When dressing for an ice or cold water dive:
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Thermal protection suits should be checked carefully for fabric cuts and separations.
Thermal protection suits should expose only a minimum of facial area.
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Mittens, boots, and seals should prevent water entry, while causing no restriction
of circulation. Wearing a knitted watchcap under the hood of a dry suit is
effective in conserving body heat. With the cap pushed back far enough to permit
the suit’s face seal to seat properly, the head will be relatively dry and
comfortable.
On-Surface Precautions. While on the surface:
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Suited divers should be protected from overheating and associated perspiring
before entering the water. Overheating easily occurs when operating from a
heated hut, especially if diver exertion is required to get to the dive site. The
divers’ comfort can be improved and sweating delayed before entering the
water by cooling the divers face with a damp cloth and fanning every few minutes.
Perspiration will dampen undergarments, greatly reducing their thermal
insulating capabilities.
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While waiting to enter the water, divers should avoid sitting on or resting their
feet on the ice or cold floor of a hut. Even in an insulated hut, the temperature
at the floor may be near freezing.
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Time on the surface with the diver suited, but relatively inactive, should be
minimized to prevent chilling of the diver. Surface time can also cool metal
components of the diving gear, such as suit valves and scuba regulators, below the freezing point and cause the parts to ice up when the diver enters the water.
Dressing rehearsals prior to diving will help minimize surface delays.
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When operating from an open boat, heavy parkas or windbreakers should be
worn over the exposure suits.
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When operating at the surface in newly formed ice, care should be taken to
avoid cutting exposed facial skin. Such wounds occur easily and, although
painless because of the numbness of the skin, usually bleed profusely.
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Diving from a beach and without a support vessel should be limited to a distance
that allows the divers to return to the beach if the suit floods.
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Extreme caution must be exercised when diving near ice keels in polar regions
as they will often move with tidal action, wind, or current. In doing so, they
can foul umbilicals and jeopardize the divers’ safety.
In-Water Precautions.
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Because severe chilling can result in impaired judgment, the tasks to be performed
under water must be clearly identified, practiced, and kept simple.
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A dive should be terminated upon the onset of involuntary shivering or severe
impairment of manual dexterity.
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If the exposure suit tears or floods, the diver should surface immediately,
regardless of the degree of flooding. The extreme chilling effect of frigid water
can cause thermal shock within minutes, depending on the extent of flooding.
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Divers and Diving Supervisors must be aware of the cumulative thermal effect
of repetitive diving. A thermal debt can accumulate over successive diving
days, resulting in increased fatigue and reduced performance. The progressive
hypothermia associated with long, slow cooling of the body appears to cause
significant core temperature drop before shivering and heat production begins.
Postdive Precautions. Upon exiting cold water, a
diver will probably be fatigued and greatly susceptible to additional
chilling:
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If a wet suit was worn, immediate flushing with warm water upon surfacing
will have a comforting, heat-replacing effect.
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Facilities must be provided to allow the diver to dry off in a comfortable, dry
and relatively warm environment to regain lost body heat.
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The diver should remove any wet dress, dry off, and don warm protective
clothing as soon as possible. Personnel should have warm, dry clothing, blankets,
and hot non-alcoholic beverages available to them.
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