This is an article by James Donaldson about cave diving.
The Dragon’s Breath Cave in the Kalahari Desert in Namibia holds the largest known underground lake. The surface area is around two hectares; the depth is unknown, charted only to 430 feet.
It sounds romantic to chart the uncharted, but the truth is that cave diving is highly technical and extremely specialized. Not even plumb lines or sonar can enter sideways tunnels or navigate small cracks as only divers can.
Safety Cave Diving
The most expensive scuba gear in the world won’t help a panicking cave diver. Cave divers are extremely vulnerable, surrounded above and below by formations with just a guideline to keep them connected. Without proper training for the psychological effects of cave diving, a panicking diver can use up more oxygen than calculated and put themselves and any fellow divers at risk. Any preparation you take should also include stress management and breathing techniques, as well as danger communication signals.
Because of the guideline and the limited swimming spaces cave diving involves, you need to be physically prepared. Learn advanced techniques in maintaining posture or trim, regulating your buoyancy (especially in tight spaces), and using controlled fin propulsion. If you want to be an advanced Cave diver, all these elements contribute to your self-control and stress management, something needed in this delicate operation.
Never cave dive without a guideline. That point of reference will lead you out even if your lights fail. If you are diving in a cave with known depth, use a shot line that leads from the top to the very bottom. You can also use it as your starting point for your guideline to explore. Make sure you’ve trained in properly following guidelines with or without visibility, and in doing multiple tasks with touch contact.
Never enter deep cave diving without first getting used to the lines. One snag can tangle your line, and panic can be deadly for a diver. On the pro side, you can clip extra air mixes and materials to increase your cave diving success.
The three basic dive lights are also crucial when you cave dive, as you are looking out for yourself and any divers with you. Cave formations can snag your line, damage your suit, and hurt your gear. Always allow yourself time to survey your environment and plan for possible outcomes. Make sure you’ve trained in using backup lights in navigation, just in case your primary light fails.
Pro-tip: If you want to know more about safety, check out the Blueprint for Survival.
Depth Cave Diving
The right certification
As divers know, depth-diving is not just about calculating how long a decompression stop should be. It’s also about managing and equipping yourself to stay calm and know what to do as you get deeper and deeper. Investing in the right certifications for depth diving will save your life.
Pro-tip: Need to know more about the right certifications? You’ve come to the right spot: Check out the TDI Full Cave Diver Courses.
Manage your air supply
As you go deeper and deeper, you will need to switch out your diving gas mix. Atmospheric air is only good until 40 meters, as the high nitrogen buildup causes stupor, also called narcosis. Past 58 meters, your oxygen turns toxic. If you want to stay higher than 40 meters for a longer time, a Nitrox mix with 22 to 40 percent oxygen is what you’re looking for.
To go beyond 40 meters, Trimix and Heliox give you a mix that replaces much of oxygen and nitrogen with helium. This makes for less narcosis and oxygen poisoning at lower depths. But you can’t use it at shallower levels, so you need to switch out before 40 meters down.
More than just the gas mix, the quality of air entering your lungs is important. Conventional gear lets you inhale the air directly and release it in the form of bubbles. In cave diving, where you should not disturb the silt or sediment, a rebreather lets you inhale oxygen silently. It also warms the air so you lower the risk of hypothermia.
Choose your suit to withstand pressure
Even out of water, you are under one ATA of air pressure. The deeper you go, the more you deal with air pressure plus the current water pressure. At 33 feet, you experience 2 ATA units of pressure (saltwater, sea level).
A drysuit made of extremely compressed and compact material keeps out the cold and is more stable for long dives, but it requires more training. Most importantly, it should withstand the pressure of going deeper and deeper, protecting your body. The suit, like the air mix, is life or death.
Pro-tip: If you don’t know where to get started, most sites have their gear broken down by activity and you can search specifically for technical scuba gear.
Cave Diving: A Different Adventure
There is more of a science to cave diving than many might guess, but with proper training, it makes it a great adventure for technical divers. The thrill is not just in the view, but in every challenge and preparation that comes before each and every dive.