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Chapter 31 — 1
Chapter 31
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DISORIENTATION
Accurate orientation whilst underwater is important for the diver so that he can find his way
back to the surface. On land the diver uses a combination of vision, the feeling of gravity on
his body, and the balance organs (vestibular system) to tell him which way is up.
When underwater, the diver becomes virtually weightless, depriving him of the sensation of
gravity and making him reliant on vision and his balance organs for spatial orientation. With
poor visibility, even the visual cues are lost, leaving the diver almost totally reliant on his
balance organs for this orientation. A sensation of disorientation requires investigation by a
diving physician.
The experienced diver can acquire some clues about his body position from:
• the way heavy objects such as the weight belt or other metal objects hang,
• the direction his bubbles are going,
• the direction of a life-line or hookah hose.
Inexperienced or panicking divers are often unable to use this subtle information. If the diver
becomes disoriented he is likely to experience anxiety. Panic can easily ensue.
VERTIGO —
OR
"DIZZINESS"
This is a false sensation of spinning or moving. The diver may either have a sensation of
himself spinning or the environment spinning about him. It happens because the balance
organ (
vestibular system
) can be unreliable underwater – it was designed to work on land.
Under certain circumstances it can supply the brain with misleading information which is
falsely interpreted as movement.
The sensation of vertigo is bad enough, but it is often accompanied by
nausea
and
vomiting
which can threaten a diver's life. These symptoms may vary from mild to very severe.
Vomiting into, and then breathing from, a demand valve is not easy underwater.