NAUI Advanced Scuba Diver
42 Night and Limited Visibility Diving
longer burn times, and they may also have a dual brightness
switch that will further conserve power. Most divers
prefer a broad beam for their primary light because it illuminates
a larger area. Some prefer a narrower beam. You
can check brightness and beam angles in the dive shop,
but remember that the angle you see in the air is not the
angle you will have in the water.
Pay particular attention to the handle configuration.
It may be a pistol grip or it might be designed to be held
by the body of the light itself. Make sure it will be comfortable
to hold for a long period of time., especially when
diving in colder waters and wearing thick neoprene gloves.
A neoprene glove’s tendency to resist forming a fist (such
as would be required around the handle of a dive light)
can cause fatigue and a hand cramp over time (figure
4-4). Some lights are designed with a hand strap and
can be worn on the back of your hand, which frees both
hands for equipment handling. Whether you choose a light
that uses disposable batteries or is rechargeable should be
determined by how frequently you intend to use the light.
The more often the light is used, the more practical it
becomes to invest in rechargeable batteries. Rechargeable
lights are also more ecologically friendly. Consider buying
spare bulbs at the time you purchase your dive lights and
keeping them with your dive equipment so they’re at hand
if you need them.
A stretchable lanyard should be attached to your
dive light and your wrist in order to prevent its loss. The
stretchable feature (usually looped around your wrist)
is important so your hand can pull free in case the light
becomes entangled.
In addition to the dive lights designed for use underwater,
you will need lights for above water use. These
include lights to use for dive preparations as well as
marker lights to help you locate the entry/exit location
at the end of the dive. It is recommended that you use
regular flashlights or lanterns for above-water use. This
conserves the batteries in your dive lights. Also, some dive
lights will overheat unless cooled by immersion in water.
While you need not have additional dive lights for the
FIGURE 4-4. Wear a glove and check to see if the light will be comfortable to use the way you will be using it.