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[Landlocked Dive Nut]

Re-printed from Dive Training Magazine, authored by Robert N. Rossier

Introduction (repeated section from scenario #1)
Diving is a pretty safe sport. Most divers are cautious and attentive in the way they prepare for and conduct themselves while diving. They know the rules and limits, they check their equipment over carefully, and they don't push the limits too far or too often. When it comes to injuries, we're probably more likely to get hurt playing softball or soccer than we are to suffer an injury on a dive. But when that unusual circumstance comes along, it's important to have a plan. After all, we can't stay underwater forever, and some problems need to be resolved pronto. We need to think about what could possibly go wrong on a dive, and have a plan for what to do if that "worst-case scenario" should arise.

With this in mind, we'll take a look [individually] at some of the most challenging situations a [recreational] diver can encounter. For each one, we define the scenario, identify the risk factors, examine the likely causes and suggest strategies for avoidance. Then we'll explore the various tactics to deal with the problem just in case it sneaks up on us.

Scenario: Out of Air
Everything is going swimmingly, and then you start to take a breath, and nothing!

Risk Factor: The most obvious risk factor for an out-of-air scenario is the inability to breathe - a situation that must be resolved right away. Panic and rapid ascents can result in decompression illness and pressure-related injuries.

Likely Causes: Out-of-air scenarios are usually the result of poor air management techniques, distraction, or mechanical failures. When divers aren't in the routine of checking air supply or they become engrossed in other aspects of the dive, time (and air supply) can pass quickly, and the onset of a low-air situation may occur unnoticed. Failure to carry secondary air supply and drifting too far from a buddy can complicate the scenario by removing the best emergency options from the table.

Avoidance: As part of the process of avoiding worst-case scenarios in diving, make monitoring your air supply a normal part of your routine. Plan your dive to ensure a supply of reserve air suitable for the particular environment and situation. Make certain your dive equipment receives a thorough predive inspection, post-dive cleaning and periodic professional maintenance. Be properly equipped with an alternative/redundant air supply, and follow established buddy procedures to ensure you're never "alone" underwater. If your diving style could leave you separated from your buddy, consider a redundant air supply rather than relying on your primary air cylinder as a backup.

Dealing with it: While running out of air is definitely a stress-inducing scenario, it shouldn't cause panic. The first thing to do is switch to an alternate air supply - either yours or your buddy's. If your buddy isn't at hand and your cylinder is "empty", begin a controlled ascent to the surface, remembering to exhale as you go. Activate an audible signal (e.g. bang on your tank with a knife) to bring your situation to the attention of other nearby divers. As the ambient pressure decreases, more air may be available from your "empty" cylinder.