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5. Kick your legs together and bring your arms forcefully down to your sides at the same time. 6. Stroke your arms up over your head as your head goes under water. 7. After you have cleared your ears, tuck your knees to your chest and turn your body so you are facing down. 8. Continue your descent to the bottom (figure 3-15). A feet-first dive is also called a kelp dive. There are variations to this dive that your instructor will show you. Shallow Water Blackout If you are free diving, before you do a surface dive, you want to breathe in and out deeply a few times before you take in a deep breath of air and hold your breath to do your dive. If you take in more than three or four breaths, you are hyperventilating excessively and this can be a problem. If you breathe in and out deeply and rapidly for more than three breaths, you lower the level of carbon dioxide (CO2) in your body. However, the deep, rapid breathing cannot raise the level of oxygen (O2) in your body. Most people do not realize that it is higher levels of carbon dioxide that gives the stimulus to breathe. When you do your dive, you use up the O2 in your system, but if you over-hyperventilate, the amount of CO2 in your body may be lowered to the point that you will not feel the need to breathe as you exhaust your available oxygen. This can cause you to lose consciousness or black out under water. Because you are most likely to black out at, or as you near, the surface on your ascent, the problem is called shallow water blackout. Shallow water blackout is easy to prevent. Just breathe in and out deeply two to four times, and on your next breath, do your dive. This will not excessively lowering the level of carbon dioxide in your body. Clearing Water from Your Snorkel Water can enter your snorkel through the open end from waves, from accidentally dipping the end of the snorkel in the water, and from doing a dive. There are two ways to clear your snorkel quickly and efficiently and with minimal effort. They are the blast clear and the displacement clear. You can also obviously clear your snorkel at the surface by lifting your head completely out of the water, removing the snorkel mouthpiece, and allowing the water to drain out of the snorkel. This technique uses a lot of your energy, and is a signal of a novice (new) diver or a problem, and is not recommended. Blast Clearing You perform the blast clear by exhaling air from your lungs forcefully as you surface from a dive. The air will blow the water out of your snorkel (figure 3-16). Take in your next breath cautiously in case any water is left in the snorkel. You can breathe past water left in the bottom of your snorkel as long as you breathe slowly. Then you blast clear again to get rid of the remaining water. Each time you take a breath following a blast clear you should be cautious to avoid inhaling water. Displacement Clearing The displacement clear is an alternative technique. It uses the least amount of energy and removes the water from your snorkel by the expansion of a very small amount of air you exhale into the snorkel as you surface (figure 3-17). NAUI Scuba Diver 54 Diving Skills FIGURE 3-16. EXHALING THE AIR IN YOUR LUNGS FORCEFULLY CLEARS THE WATER OUT OF YOUR SNORKEL.


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