Every movement a diver makes underwater effects his position. When a canine dog-
paddles, he propels water downwards to keep his head above the water. A diver who dog-paddles also moves himself upward in the water. Some divers use their hands to adjust their buoyancy instead of adding air to their buoyancy compensator (BCD). Every time the diver moves downwards in the water (causing him to become more negatively buoyant) he would compensate for his decrease in buoyancy by pushing water downwards.
When a diver swims with his hands, his breathing rate increases from the extra exertion and he empties his tank more quickly. If the diver dog-paddles, he may also stir up bottom sediment (decreasing the visibility) and he runs the risk of accidentally slamming his hands against coral or other objects.
One of the most important techniques a diver can learn is to properly control his buoyancy using his BCD and his lungs. New divers tend to struggle with buoyancy until they learn to notice small buoyancy changes as they ascend and descend. These small changes alert a diver to the fact that he has changed depth. By responding quickly and effectively to small buoyancy changes, a diver maintains his desired level in the water and avoids an uncontrolled ascent or descent.
A diver unconsciously uses his hands to counteract the small buoyancy changes. As a result, he does not notice that he is descending, and continued to become more negatively buoyant until his dog-paddling is no longer sufficient to keep him off of the ocean floor. At this point, he completely loses buoyancy control and suddenly plummet downwards, unable to inflate his BCD quickly enough to counteract his descent. Furthermore, every time he stopped swimming, he sank downwards once he stopped moving his hands. “Cheating” by using his hands prevents him from noticing small buoyancy changes and fine tuning his buoyancy using his BCD and lungs.
Many divers unconsciously use their hands to make small adjustments to their buoyancy. This seems to be a natural response, similar to kicking on the surface. A good way to break the habit is to have the diver consciously hold his hands still by placing them in a pre-determined position. I recommend hand positions such as clasping the hands in front of the diver, crossing them on the diver’s chest, holding onto the BCD shoulder straps, or “superman-ing” in front.
Good buoyancy control not only requires the ability to properly use both the lungs and the BCD, but it also requires that a diver is able to recognize small buoyancy changes. The best divers make tiny adjustments to their BCDs and lung volume to maintain perfect neutral buoyancy at all points during a dive. If a diver uses his hands to keep himself up or down, he is depriving himself of the opportunity to fine tune his buoyancy techniques and experience the thrill of swimming effortlessly and weightlessly through the water
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