418 Dive Log Australasia JUNE 2026.pdf

The challenge they have been set is to descend quickly down a reef wall to 60m on a single cylinder of air, collect a handful of sand and then come back to the surface. The two individuals accepting the challenge are young, physically fit, good swimmers and experienced divers. This is an initiation ceremony. Joining them today are a few colleagues; all completed the task previously, when they were the new guys on the team. Today, they are just here to cheer on the new boys. The divers enter the water together and descend to 20m, where the “veterans” stop and watch the two “newbies” continue down. At first, they see two streams of bubbles, then the two streams become one. Then the bubbles stop. They wait, time passes, and they wait a little longer. After 15 minutes with no sign of their missing buddies, concern turns into full-blown anxiety. Two of them head for the surface to begin a boat search, while the others stay underwater, desperately peering down into the blue. But, on this day, there will be no miracle. The two divers will never be seen again. A Dangerous Game Every year, people die diving deep on a single tank of air. Many of the victims are experts, instructors, and super-qualified individuals. The scuba diving training agencies set depth limits for diving with air, and the manuals warn that it is not safe to exceed the limits, but they rarely explain why. This seems to encourage many to interpret the warnings as just well-intentioned advice that might apply to ordinary people, but it certainly doesn’t apply to divers with their years of experience. So, while they may faithfully pass the warnings onto others, when they dive with their peers, they don’t practice what they preach and sometimes get into difficulty, with tragic results. backslapping as the divers prepare their gear. The gauntlet has been thrown down. The Foolishness of Deep Air By Simon Pridmore I t’s a beautiful day. Conditions are perfect with flat seas and a clear blue sky. The atmosphere on the small boat is thick with testosterone, and there is much whooping and hollering and

These divers are ignoring a basic truth. Surviving dives like this has nothing to do with courage or competence. It is simply a matter of human physiology, and we are all human and have human frailties. What is the Problem? The problem with deep air diving is not the “deep” word. Diving deep is fine, as long as you have the right experience, the right equipment, the right training, the right combination of gases in your cylinders and an independent source of breathing gas (and enough of it) to allow you to ascend safely in the event of a delivery issue, such as a regulator or valve failure. We can manage the depth. The problem is the air, and what happens to our bodies and minds when we breathe air underwater. There are four major issues, which, together, can combine to cause a diver insurmountable problems. Problem #1 Air contains oxygen, a gas that we need to sustain life, but which is toxic if we consume too large a dose, inducing disabling convulsions that, if they

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DIVE LOG Australasia #418.June ‘ 26

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