by Dr. Thomas Powell:
Diving is a unique sport that can capture the hearts and interests of people of all sorts. For many, the urge to go further, learn more, and in some cases go deeper, will keep divers in the water. The problem with this mindset is, some people may push too hard, or go too far out of excitement or even bravado. These factors suggest that any and all recreational divers, at any level, must remember that one of our biggest objectives is to avoid decompression requirements unless we plan for them. Venturing beyond your no decompression limit (NDL) is a risk that any diver faces if he or she does not monitor their instruments and the overall situation.
To avoid this potential life-threatening problem of passing your NDL, there are various actions a diver can take.
Learn your computer! – Almost every computer today comes with bells, whistles, and alarms to let a diver know when a problem has occurred, or when the diver is approaching a problematic scenario. There is no excuse for any diver failing to learn the proper use of his or her computer. The computer is an essential item required for all SDI/TDI/ERDI divers. When lights flash or numbers change, the diver needs to know what this information means. Learning to properly read your computer and react to what it says, will help a diver get wet the next day. Similarly, the computer will track time as the diver approaches his or her NDL. This easily recognizable data can allow a diver to avoid crossing that threshold and going into a scenario requiring decompression.
Create a game – Take the time to use the information displayed on your computer to create a game. Monitor data, set goals, set limits, or even follow display data in a manner that forces you to look at your computer or gauges every short period. This action will force you to see your display and recognize information. A task as simple as this can force a diver to see NDLs approach or problems arise.
Make a deal with your buddy to check each other – Prior to any deep dive (or any dive for that matter), a diver can establish a plan with his or her buddy to check each other’s computers or gauges every so often. This action will ensure each diver has a redundant data check periodically. As NDLs are approached, and if a diver misses this information, the buddy may recognize the issue before problems arise.
Monitor your surroundings – Computers and gauges can tell us our depth. Despite this factor, if color changes or environmental factors alter, you may have drifted a bit deeper than planned and not yet noticed on your computer. Even if you plan to dive deep, we all know that going deeper will reduce your possible bottom time and therefore, your NDL. Pay attention to where you are, and use these observations to create a mental reference to check your computer.
Map out your plan in advance – Our training teaches us to plan deep dives in advance. Prior to any dive, set a route, walk through your objectives with your buddy(ies), and plan for possible problems. If you and your buddy set limits for max depth and understand your probable route, you may be able to foresee potential problems, or recognize when your buddy deviates from the proposed plan. Understanding when and where your team should be, will help all parties associated better pre-plan for avoiding NDLs.
The goal of any dive should be to have a good time, accomplish possible objectives, and be able to dive tomorrow. When we fail to meet these goals, bad things can happen and life-threatening problems may arise. As divers and dive professionals, we need to understand our actions, and ensure safety throughout a lifetime of enjoyment, no matter how deep someone chooses to go.
Dr. Thomas Powell – Owner/Instructor Trainer (SDI/TDI/ERDI) for Air Hogs Scuba, Garner, NC