NAUI Advanced Scuba Diver
56 Introduction to Deeper Diving
FIGURE 5-8. Pre-dive equipment checks are always an important step and even more so when executing a deeper water dive.
Whenever possible and practical, it is recommended
that surface support personnel be present during deeper
dives and that these individuals be divers. Their function
is to assist in the preparations to dive, to keep a record of
diving activities (times, depths, etc.), and to do any and
all physical work required following the dive (retrieving
the down line, pulling the anchor, etc.). The divers
should keep physical exertion to a minimum following
a deep dive because activity increases the chances of
decompression sickness, as does drinking alcoholic or
caffeinated beverages and taking hot showers.
It is a good idea to check your equipment three times
before entering the water for a deep dive (figure 5-8). You
should inspect it yourself after suiting up, your buddy
should check it, and the surface support person should
also look you over before you enter the water. It is safer
and easier to make corrections to equipment above
water than it is underwater. Upon entering the water
and agreeing with your buddy to begin your descent on
the down line, again make a quick check of your gear to
make sure it is secure and properly oriented, then check
your timing device or computer to make sure it is set to
begin measuring elapsed time. Your descent should be
controlled. Descend slowly, feet first and eye-to-eye with
your buddy. Stop occasionally to recheck your gear and
to test your buoyancy. If you sink with a full breath, you
need to add air to your buoyancy compensator.
Upon reaching the planned depth, test your buoyancy
again by letting go of the down line briefly. If you are
too heavy or too buoyant, grasp the line while you make
adjustments, then test your buoyancy again. Do not leave
the descent line until your buoyancy is correct. Next,
select the desired direction in which to begin your dive
and take a moment to orient yourself to the surroundings
and to the down line. Note the direction of any current
and be aware that the current at the bottom may run in a
different direction than the surface current.
As the dive progresses, you should frequently reference
your proximity to the ascent line. Also reference
both your instruments and your buddy’s. If there is a
difference in the readings on your gauges compared to
those on your buddy’s gauges, use the more conservative
reading. In other words, use the deeper reading gauge for
the determination of your present depth. If you are both