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tion, which varies according to the location. For absolutely
exact map work, local declination (which is usually given on the
map) should be taken into account.
- General orientation on the diving site
Before diving, check the main compass bearings at the diving
site, paying special attention to memorizing the direction
of the shoreline and bearings of landmarks that may be of
importance.
UNDER WATER
Natural aids to underwater navigation
- The underwater extension of the shore’s inclination tells
the diver if he is following the shoreline. Be extremely
careful, however: underwater ridges may lead you
astray. Surface occasionally to check.
- The dip and stratication of rocks on the shore can often
be followed over large areas under water.
- Sand ripples form long lines parallel to the shore.
- The direction of currents should be noted by their effect
on algae or drifting particles. (Use the compass to check
the bearing of the current).
- In shallow water, the sun’s direction can be seen from
shadows on the bottom, or by looking toward the
surface.
- Swimming in a straight line along the bottom is greatly
facilitated if you can line up three distinctive objects in
