A buddy is there to help you check your gear and, when underwater, to help you in case of an emergency. After you are in the water, put on the fins, mask, and snorkel, and, carrying a weight belt, walk slowly backward to the middle of a shallow area. Sit on the bottom with the weight belt across your thighs. When inhaling, the body should make a slow rise. If it does not rise, then the weight should be decreased. This makes the body neutrally buoyant. Always make sure the mouthpiece and mask are clear. Free ascent should also be learned in case of emergency and the diver must ascend without his gear. The ascent is made slowly, and a constant exhalation of air is required. If you hold your breath during an ascent after breathing compressed air, and air embolism can be caused.
This is when air escapes the lungs and enters the bloodstream, causing bubbles to form in the veins. These bubbles block the blood flow to the brain, causing death. Always exhale during a free ascent. The “buddy breathing” and “ditch and recover” methods are also important in diving. Buddy breathing is when you use your partners’ air during a dive if yours is not available. The mouthpiece is to be switched back and Korell 6 forth every two breaths. The ditch and recovery is when a diver ditches his gear, and recovers all of it in ten feet of water. These are all a few of the techniques used in scuba diving. In scuba diving, you can always learn something new.
There are may techniques to learn and can always be improved (Counsilman and Drinkwater 34-39). In diving, there is always a chance you could be hurt. Safety is crucial, and there are quite a few physiological concerns in the sport. When descending in the water, Boyle’s law goes into effect immediately. As the water pressure surrounding the diver increases, the volumes of air both inside and outside the body of the body decrease in size. This pressure creates a compressing effect on the body that can result in injuries called Barotrauma. This can be avoided by equalization. The two major forms of Barotrauma on descent are internal and external squeeze.
The sites of internal squeeze include the middle ear, the sinuses, and, occasionally, the teeth and intestines. As water pressure increases on descent, the air space in the middle ear is reduced, causing a vacuum, with the outside water forcing the flexible eardrum inward. If the internal air pressure is not equalized, the eardrum may become perforated. The sinus squeeze is when the sinuses are blocked. There are four sinuses that are filled with air and called the frontal, ethmoidal, maxillary, and sphenoidal, and come in pairs. The sinuses must be equalized just like the middle-ear space.
Due to head colds, allergies, sinusitis, or smog, the sinus may become blocked, thus causing a sinus squeeze (Griffths 71-76). External squeezes are caused by the divers’ equipment, such as the mask or wetsuit. When an equipment squeeze occurs, body tissues are pulled out and away Korell 7 from divers, rather than pushed into them. The mask squeeze, which may be the most common external squeeze, is caused by the inability to equalize the air pressure between the mask and the face on the diver’s descent.
To prevent a mask squeeze, the diver should exhale through the nose when suction is experienced on the face. A slow descent is also a way to help avoid this problem. A suit squeeze is another kind of squeeze to avoid. This is rare, but air pockets form between the suit and the skin and blood vessels on the surface of the skin could rupture. To prevent a suit squeeze, one must vent the suit of air and fill the former air pockets with water (Griffiths 76-78). The ascent is the same to the descent in relation to Boyle’s law, but in the ascent, the surrounding pressure decreases, causing air pockets to expand.
The two most common types of ascent problems are lung overexpansion and decompression sickness. In lung overexpansion, when a diver breathing compressed air returns to the surface, air in the lungs will expand due to the decreasing water pressure. A diver must breath regularly on the ascent in order to allow this reexpanding air to vent itself normally. Breath holding, uncontrolled ascents, or airway blockage could cause the expanding air to rupture the air sacs in the lungs, allowing air bubbles to enter the body and resulting in tissue damage, blood circulation blockage, or both. Lung overexpansion can be avoided through self-control.
Divers should be able to perform a controlled ascent at any time, with normal breathing or exhaling slowly along the way. Scuba divers must never hold their breath while ascending (Griffiths 78). Decompression sickness, aka: “the bends”, is one of the most feared diving maladies. With increasing depth, the partial pressure of nitrogen also increases. As Korell 8 the partial pressure of nitrogen elevates, it becomes more soluble in the tissues of the body.
At the bottom, the diver with nitrogen dissolved in the tissues and bloodstream experiences no apparent problems. However, when ascending, significant pressure/volume change occur. If the rate of ascent is faster that the ability of the body to vent nitrogen through normal breathing, the nitrogen gas will expand and “bubble-out” of solution. To avoid the bends, diving well within the limits of the U.S. Navy no-decompression tables and following them is the only way (Griffiths 81-82). Hyperventilation, or shallow water blackout, has more potential to occur on skin dives rather that scuba dives, but may occur on both.
Hyperventilation results when rapid, forced exhalations significantly lower the levels of oxygen and carbon dioxide in the bloodstream, which may lead to unconsciousness. To treat hyperventilation, the airway should be opened by hyperextending the neck, mouth-to-mouth respiration may not be necessary if the carbon dioxide level build up and triggers the breathing mechanisms, which often happens (Griffiths 85). In conclusion, scuba diving is not a simple sport. There are many complexities that go along with it. In time, it has come along from being a difficult sport that is only allowed for a selective few, to a sport that almost anyone can participate in. The improvement in its technology makes it much easier for others to learn.
Also, more research has been done on it, and now there is almost nothing more to research about it. It is a very complex topic due to the scientific side of it. There are many scientific laws and there are many restrictions related to it. The only drawback of learning how to scuba dive is the cost. But if you are willing to spend about $450 and want to learn Korell 9 a lot more about scuba diving than the underwater portion, then by all means–go ahead. After all, it is a completely different world down there.
Bibliography
- Counsilman and Drinkwater. Beginning Skin and Scuba Diving. Belmont, CA: Wadsworth Publishing Company, Inc.
- 1964. Griffiths, Tom. Sport Scuba Diving in Depth. Princeton, NJ: Princeton Book Co., Publishing. 1985. NAUI–Adventures In Scuba Diving.
- St. Louis, MO: Mosby–Year Book, Inc. 1995. Nonnelly, Doug. Personal Interview. 1 Nov.
- 1998. Reseck, John. Scuba–Safe and Simple. Englewood Cliffs, NJ: Prentice Hall, Inc. 1975.
