NAUI Advanced Scuba Diver
74 Search and Recovery
in establishing the search area. What is the depth? What
time is it? Which way is the current flowing and how
strong is it? If you were diving in the vicinity, what was
the bottom like? Were any underwater landmarks or
distinctive features nearby? Information such as this can
help a great deal and may lead to successful search, but
don’t trust it to memory. Write it down.
The second step is to select an appropriate search
pattern. However, you don’t always have to conduct an
underwater search. In some situations, snorkeling on the
surface is all that is necessary. No matter which technique
you use, your search needs to employ the appropriate pattern
and be well planned (figures 7-4, 5, 6, 7).
There are two basic types of search patterns: circular
and straight line. There are countless variations of these
basic types, but we will look at only a few of them that
are useful for areas where the bottom is relatively unobstructed.
A circular search is most useful when the point of
loss is rather well defined. The idea is to extend a line
from a marked center point and search in ever-widening
circles until the lost object is located. The technique
usually uses a heavy weight as the hub for the sweeps,
but your buddy can serve as the anchor point while you
make the circular passes. It is necessary to know when a
circle has been completed. This can be done by placing
an object on the bottom, marking the bottom, noting a
compass heading, or by being signaled by a buddy who
remains at the hub and signals completion of a circle by
FIGURE 7-4. contour search pattern
FIGURE 7-7. circular search pattern
FIGURE 7-5. parallel search pattern
FIGURE 7-6. expanding square search pattern