Page 132 - Mexico Diving From the Caribbean to Pacific Isles

thorough understanding of dive tables
A and/or computer savvy and the ability
to perform controlled, slow ascents and
safety stops are all important. Many divers
enroll in a wall diving specialty course to
ensure that they are adequately prepared.
Since the majority of walls are effectively
bottomless and the water often gin-clear,
it is easy for a diver to descend beyond the
planned maximum depth, even beyond the
sport-diving limit: 130 feet or 40 m. That is
one obvious reason why buoyancy control
is a critical skill for wall divers. Because a your maximum depth and still have plenty
diver becomes more negatively buoyant
as he descends, it is important that he add
air to his BC as he goes deeper on the wall.
This slows the rate of descent and makes it
easier to establish neutral buoyancy upon
reaching the desired diving depth.
egardless of the environment you dive, of 100 feet (30 m) but some divers may
begin to feel its effects at shallower depths.
R the deepest part of your dive profile Symptoms include lightheadedness, eu-
phoria, mental confusion or a “drunken”
should be done first. Wall divers generally feeling. These symptoms subside when the
descend to their maximum planned depth, diver ascends to a shallower depth. Surface
and then ascend to progressively shallower signaling device is a good safety accessory
depths as they explore the wall. Those div- for wall divers. When drift diving along the
ing from an anchored boat often dive at wall, the boat follows the bubbles and picks
one depth during the against-the-current the divers up as they surface. The combina-
leg and ascend to a shallower depth for the tion of divers surfacing at different times
return leg. Having something to explore at and places, changing currents and choppy
any depth is one of the attractions of wall surface conditions can cause the boat crew
diving — you can begin ascending from to lose track of your whereabouts. You may
surface and find the boat far away and the
of diving left before reaching the top of the crew not looking in your direction. In this
wall. Since wall diving often involves diving case an audible, inflatable or reflective sur-
deep, wall divers should watch for the onset face signaling device, or better yet all three,
of nitrogen narcosis, a physiological condi- will come in handy.
tion that occurs when the nervous system
is exposed to increased nitrogen pressure.
Nitrogen narcosis usually occurs at depths