NAUI Advanced Scuba Diver
32 Navigation
dilly-dally along the way. Also, remember that your air
consumption rate increases both with depth and with
exercise level. You should not only use a “standard” kick
and speed but also adjust your measurements as your air
consumption rate changes with depth.
With experience, many divers are able to use just
a “feel” for distance covered. Whatever method you
choose, the most important concept is to pay attention
to distance in order to find your dive site or to navigate a
pattern, such as a square, effectively.
NATURAL NAVIGATION
Natural navigation is the use of “landmarks,” depth,
and other visual aids to establish your position. You are
familiar with the use of environmental aids for references.
Examples include the direction of light, formations
of reefs and sand ripples, depth and bottom contour,
currents and surge, and self-made references such as silt
trails and rock piles. Keen observation of such aids can
help you recognize areas you have visited previously and
can serve to help in determining where you are.
There is more to natural navigation underwater,
however, than merely taking note of a few environmental
aids. To be most effective, also apply the following procedures:
1. Use starting references. If you are diving from
a moored or anchored boat, carefully note your
point of origin after you descend and before you
swim off to begin your activity. In clear water, you
can even take advantage of a bird’s-eye view as
you approach the bottom. It helps to study charts
of the area where you will be diving so you can
form a mental picture of the overall area. If your
dive site is on a slope, note the depth of the anchor
point at which you begin. If you return to that
depth as you navigate back to the boat, you will be
along the same contour as the anchor. If you start
at a known point, such as a rock out-
cropping, it will be easier to return to an area by
starting at the known reference on subsequent
dives. Concentrate on being able to recognize your
starting point underwater without having to surface
to reference the boat (figure 3-5).
2. Follow a pre-planned general course. Natural
navigation is much more effective when a pat-tern
is followed than when you dive randomly. Your
course may be a square, a rectangle, a triangle, or
simply out-and-back; or you may plan to follow
a depth contour. Following a planned course will
better enable you to return to a starting point or to
relocate a specific area during subsequent dives. It
is not necessary to follow
the general course precisely. Some deviation is
permissible to investigate items of interest. When
FIGURE 3-5. Observing your starting point carefully at the beginning
of your dive can make it easier to recognize later.