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From: "Andrea Zaferes" Date: Tue, 30 Jul 2002 22:10:54 -0400 Reply-To: PublicSafety@wateroperations.com The solution, as was taught to me by Hendrick is to start out neutral. Learn how to plan dives and move efficiently throughout the dive so that you have plenty of air left in your tank at the end of the dive (700-1,000 for sport diving). Remember that if you drain your tank to 500 psi then you will have to overweight yourself by at least 2-3 lbs just to compensate for the loss of the air weight in your tank. You should not still be diving with so little air for many reasons. Then, when it is time to ascend all you should have to do is get in a vertical position and "think up" and you should slowly begin to rise at 2 sec/ft. If you have to kick then you are not neutral. There should be minimal air in your BCD, especially if you are wearing only a thin wetsuit and are not diving below 100 feet. As you ascend bring your power inflator out forward at shoulder level and gently depress the exhaust button periodically. If you find yourself having to kick to stay in place or rise then you exhausted too much. You only want to vent enough air to keep you neutral at your solar plexus level. The higher the power inflator, the more air it will vent. If you vent just a few ounces too much you will become a few ounces negatively buoyant and the Great Compensation Chase will begin, although it will be manageable, as compared to errors in pint size volumes. Practice hovering. At any point during the free ascent you or your buddy can signal "stop." Stop for a few seconds and then continue with the ascent. It is particularly important to play this game in depths at 15 feet or shallower since that is where the greatest pressure changes occur. Every diver should be capable of making 2 sec/ft ascents and hovering at any depth even if they always dive with an ascent/descent line. Always have practiced contingency plans. You cannot guarantee that you will always be able to reach or find that line so be prepared to make free, slow ascents and safety stops. Being neutral from start to finish is the key. As one of course directors, George Safirowski, frequently points out, too many of today's divers are so unfamiliar with the feeling of being neutral because they always dive overweighted, that they feel uncomfortable and even nervous when they are properly weighted. They tell us that they feel out of control, they think they are rising when they are not. It takes time to be comfortable with feeling weightless, neutral, particularly if you have many hours negatively buoyant hours underwater in addition to all the years of being negatively buoyant on land. Observe divers. Too many divers kick continuously as they progress forward throughout their dive, and during the few times that they do stop to look at something their hands and arms start sculling. Divers are not sharks, we will not die if we stop kicking, but sadly many divers will rise or fall if they stop kicking. They have learned to compensate for overweighting and poor buoyancy skills by kicking and sculling. If you want to really learn about this kicking compensation have an instructor take you in a pool and remove your fins in the deep end. Without sculling your hands, work on slowly rising and falling by just adjusting your body posture. If you gently raise your arms you will fall slowly. If you gently take your arms out and let your chest muscles relax "open" you will rise. Keep on breathing with normal inhalations and slightly gentler, slower exhalations. Do not use your lungs as elevators. Change your body posture and sometimes change your breathing by an ounce or two and that should be all you need to rise, fall, and stop. Practice hovering in a cross legged position, gently remove your mask, breathe, gently don the mask, breathe, and then gently clear the mask by exhaling just enough air to clear the mask not the pool (bubbles should not escape from the mask). This drill will make you a far safer diver for many different reasons. Find an instructor who can move effortlessly and have that instructor trim you out. In the first buoyancy control class I taught with Hendrick 15 years ago I was amazed to learn that just the location of the weight on the belt can make as much as a four pound difference. I watched him take ten or more minutes per person, meticulously moving weight around on each student's belt and then remove pounds just by getting the weight in the right place for each person's body. Make sure all your gear is secured to your body so that you and your gear are one. When you move your gear should move with you at the same time in the same way. Dangling gauges, octopuses are not only safety hazards, they ruin good buoyancy control, which incidentally means far more than just being able to hover and ascend slowly. If your feet are positively buoyant then purchase ankle weights and adjust the amount of lead shot to make your feet stay where ever you put them. Hendrick, for example, has four pairs of ankle weights, with each pair weighted for different exposure suits (wet suit socks, wet suit boots, drysuits with thin socks, dry suit with thick booties). Practice moving slowly and being neutral in the pool, teach your students to do this if you are an instructor, and divers will have a fighting chance in open water. Learn how to truly "be" in the water, and then hovering and 2 sec/ft ascents will become second nature. We greatly thank the scientists for figuring out what we need to do to be safe, and we thank industry leaders like those at DAN for communicating the information out to everyone. It is up to us to figure out how to make sure all divers are capable of performing these recommendations and standards. Safe diving always, Andrea
Andrea Zaferes |
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