Advice on Establishing Proper Neutral Buoyancy While Scuba Diving
Diving with my friend on his first dive, I was laughing so hard that I could barely keep my regulator in my mouth. On the surface, my friend is calm and in control. He is a strong swimmer – on snorkeling excursions he swims barefoot while I use fins. He was certain that diving would be easy for him. However, the moment he descended, his swimming skills and control went out the window and he began to dog-paddle. The deeper he went, the more frantic his dog-paddling became. After a few minutes of observation (and snickering), I figured out why he was swimming so strangely.
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. My diver was using his hands to adjust his buoyancy instead of adding air to his buoyancy compensator (BCD). Every time he moved downwards in the water (causing him to become more negatively buoyant) he would compensate for his decrease in buoyancy by pushing water downwards.
I insisted that my friend stop using his hands to swim. 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. However, the main reason that I wanted my friend to stop swimming with his hands was that it was preventing him from learning good buoyancy control.
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.
My friend was unconsciously using his hands to counteract the small buoyancy changes. As a result, he did not notice that he was descending, and continued to become more negatively buoyant until his dog-paddling was 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 was preventing 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. I have to train the majority of my students not to swim with their hands. A good way to break the habit is to have them consciously hold their 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.
learn more at :::: http://scuba.about.com/od/skills/a/No-Hands.htm