6-52 Change A
U.S. Navy Diving ManualVolume 2
The first and most important action that a trapped diver can take is to stop and
think. The diver shall remain calm, analyze the situation, and carefully try to work
free. Panic and overexertion are the greatest dangers to the trapped diver. If the
situation cannot be resolved readily, help should be obtained. A new umbilical can
be provided to the surface-supplied diver; the scuba diver can be given a new
apparatus or may be furnished air by the dive partner.
Once the diver has been freed and returns to the surface, the diver shall be exam-
ined and treated, bearing in mind the following considerations:
The diver will probably be overtired and emotionally exhausted.
The diver may be suffering from or approaching hypothermia.
The diver may have a physical injury.
A scuba diver may be suffering from asphyxia. If a free ascent has been made,
gas embolism may have developed.
Significant decompression time may have been missed.
Equipment Failure. With well-maintained equipment that is thoroughly inspected
and tested before each dive, operational failure is rarely a problem. When a failure
does occur, the correct procedures will depend upon the type of equipment and
dive. As with most emergencies, the training and experience of the diver and the
diving team will be the most important factor in resolving the situation safely.
Loss of Gas Supply. Usually, when a diver loses breathing gas it should be
obvious almost immediately. Some diving apparatus configurations may have an
emergency gas supply (EGS). When breathing gas is interrupted, the dive shall be
aborted and the diver surfaced as soon as possible. Surfacing divers may be
suffering from hypoxia, hypercapnia, missed decompression, or a combination of
the three, and should be treated accordingly.
Loss of Communications. If audio communications are lost with surface-
supplied gear, the system may have failed or the diver could be in trouble. If
communications are lost:
Use line-pull signals at once. Depth, current, bottom or work site conditions
Check the rising bubbles of air. A cessation or marked decrease of bubbles
could be a sign of trouble.
Listen for sounds from the diving helmet. If no sound is heard, the circuit is
probably out of order. If the flow of bubbles seems normal, the diver may be