NAUI Advanced Scuba Diver
34 Navigation
FIGURE 3-7. Whether wrist or console mounted, aligning the compass properly is critical to accurate navigation underwater.
(figure 3-7). The following procedures will be helpful to
learn the practical application of the compass for diving:
1. Have a starting heading and follow a general
course. Most of the time you will not use a compass
as a constant reference to follow an exact heading.
Instead, the instrument will serve as a general
reference. The compass is especially useful in areas
devoid of natural aids, such as sandy bottoms. At
the outset of every dive, you should set an initial
bearing as a point of reference. This bearing may
be the direction of shore, the direction opposite
to any current, or simply arbitrary. The direction
isn’t as important as having a direction of
reference. Just as in natural navigation, you and
your buddy can remain together more easily and
you will be better able to navigate if you follow a
per-determined general course. Again, the course
need not be exact, but the advantages of adhering
to even a rough pattern will become obvious with
experience (figure 3-8).
2. Navigate from point to point. During natural navigation
you were instructed to move from
one environmental aid to the next. Except in
extremely limited visibility, the same principle
applies to compass navigation. The difference
between compass navigation and natural navigation
is that compass navigation is more accurate.
When using the compass, look over it and along
the bearing and select the most distant object you
can see for your heading. Move to that object and
repeat the process. By using this “leap frog” technique,
it will not be necessary to look constantly
at your compass, and you can spend more time
enjoying your dive.
3. Be aware of the effects of deviation. The compass
is a magnet, and it is attracted to ferrous metal
objects, other magnets, and electrical fields. Be
aware that the compass will not provide an accurate
reading when in close proximity (usually less than
a meter) to large attracting objects, including not
only shipwrecks but also steel scuba cylinders, other
magnets, or dive lights. You can test the effects of