NAUI Master Scuba Diver 182 Rescue and Emergency Procedures you swim to the surface at the normal ascent rate. The risk from this type of ascent is inhaling bacteria or fungi that are almost certain to be present in the B.C. Buoyant Ascent A diver may elect to execute a buoyant ascent by removing the weight belt or retaining expanding air in the buoyancy compensator (figure 6-3). Because control of the rate of ascent is very difficult, a buoyant ascent is considerably more risky and should be used only if you cannot swim to the surface. You may elect to start a buoyant ascent at the bottom or change an emergency swimming ascent to a buoyant ascent on the way up. Once the weights are discarded, the diver arches backward into a belly-up position, extends arms and legs horizontally (spread-eagled), and continues to exhale gently to the surface. This technique is known as flaring. Remember, expanding air from your regulator and cylinder may become available to breathe as the water pressure is reduced. A skilled diver will practice assuming the buoyant ascent position, as it is useful in circumstances other than out-of-air emergencies. For example, the accidental loss of weights, a jammed inflator or exhaust valve, or over-inflated BCs or dry suits. An excellent way to practice this technique is to surface dive in snorkeling equipment without a weight belt, and practice flaring on ascent. Even in a full wetsuit, the ascent rate is remarkably slowed. Dependent Ascents Dependent emergency ascents require a buddy who is trained, willing to assist, in the immediate vicinity, and who has enough air for two divers. The procedures should be discussed with your buddy and rehearsed frequently while on dry land, until your response to an out-of-air sign is fast, automatic, and elicits little or no anxiety on you or your buddy’s part. Shared Air Ascent: Alternate Air Source The alternate air source has evolved to become the preferred means of resolving an out-of-air situation. The FIGURE 6-3. DIVER DITCHING WEIGHT BELT PROPERLY alternate air source may take several forms, all of which provide an extra second stage regulator so that each diver has a source of air. The “octopus” is an extra second stage regulator with a longer hose for the out-of-air diver’s use (figure 6-4). Another type of alternate air source is a combination regulator and BC inflator mechanism. Many divers prefer this type, as it eliminates one extra hose on the scuba regulator. The method of air sharing depends on the type of alternate air source. With the octopus configuration, the donor normally gives the out of air diver the octopus regulator. Some divers prefer to rig the longer hose on their primary second stage, passing that to the out of air diver, and then breathing on the octopus regulator themselves. After the out-of-air diver receives the second stage from the buddy and has established breathing control, the divers hold firmly to each other, look to the surface, and upon mutual signal agreement, ascend at a normal rate, while breathing normally and controlling buoyancy. Eye contact should be maintained during such an ascent.
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