By Dr. David Sawatzky
Cave diving is a very unforgiving activity. You have to keep track of a large number of variables, concurrently. If you make a mistake or lose track of one of these variables, you will very likely die. There is very little margin for error.
In open water diving you have to keep track of your depth and time if you want to avoid decompression (these days your computer does that). You have to keep track of your remaining gas supply so that you finish your dive and/or surface before you run out of something to breathe (many computers also do that). You have to keep track of which way is up. You more or less need to keep track of where you are, although in some situations you can just surface and swim back to your start point or get picked up. Finally, you need to keep track of your buddy. If you lose them, pop up a few feet and look/listen for bubbles, unless they are diving CCR: no bubbles, no noise, easy to lose track.
Caves are Complicated
In cave diving things are much more complicated. Depth and time still determine decompression, but the shape of the cave determines your depth and often makes decompression very challenging. For instance, in one cave I dived to a depth of 200 feet (60m). Decompression stops obviously started quite deep and I decompressed up to my 30-foot (10m) stop. The cave then went back down to a depth of 60 feet (20m) before rising again to the exit. This decompression challenge is almost impossible without computers. In addition, this cave at a depth of 10 feet (3m) was very small and had ridiculously strong current. The water temperature was just above freezing. Practically, you had to do your 10-foot (3m) stop at a different depth. Oh yes, the cave was also 4,500 feet (1,500m) above sea level!
Gas supply in cave diving is critical. There is no simple ascent to the surface. You must always have enough gas to get back to the entrance or another exit. How much gas does that take? If you think you will use half of your gas on the way in and turn around to exit, I’ll say a prayer for you at your funeral.
One of my most challenging dives from a gas management perspective involved exploring downstream in large passage with current too strong to swim against. We had laid approximately 1,500 feet (500m) of line on previous dives and had a coil containing several hundred feet of one-inch nylon webbing for this dive. We very quickly swam to the end of the line. I tied the coil of webbing on and set off. I would drift along and estimate the distance as I travelled over the floor. When I estimated I had gone about 50 feet (15m) I would start to look for a place to tie the line to the floor with the objective of tying off the line at least once every 100 feet (30m). I also had to watch the floor very carefully. If the line I was laying started to move sidewards over the floor I had to immediately find a tie off, since that meant the cave passage was turning. In this situation the line can be pulled over to the side of the passage and run through an area too low for you to get through when you try to follow the line back out of the cave.
The plan was to use about 70 cubic feet of gas on the way in, leaving over 250 feet of gas for the exit (we were carrying several tanks each). When we had used 70 cubic feet of gas I had only a small amount of line left; however, the plan said it was time to exit. I tied the coil to the floor of the cave and we did a quick survey of the line as we pulled ourselves out of the cave using the line and floor to make progress. When I added up the numbers I learned that we had laid approximately 1,000 feet (300 m) of line on that dive. We were a half-mile (800m) downstream in the passage when we turned around!
A few weeks later we were back with more line and even more tanks. When we reached the end of the line I untied the small remaining coil and started to lay it out. Before I ran out of line I reached the end of the cave passage and surfaced in the river, less than 100 feet (30m) from where we had turned around on the last dive! However, I don’t regret stopping the previous dive where we had. The gas management plan was there for a reason: to keep us alive. The spirit of adventure is strong in cave diving, but so is the need for discipline. (Needless to say, we used the newly discovered entrance/exit on future dives!)
Orientation is also critical in cave diving. You typically have good visibility on the swim into the cave and new cave divers often don’t realize that they are stirring up the silt with their fins or that their bubbles are knocking silt off the ceiling. As a result, when they turn to exit the cave they discover that visibility on the exit is going to be zero. Either they cannot find their way out, or they move so slowly that they run out of gas before they get back to the entrance. In addition, many caves are very complex and divers often get confused and cannot find the exit before they run out of gas.
Keeping track of your buddy also can be extremely challenging, with zero visibility, very small passages/spaces, high task loading and your buddy may be on the other end of the tape measure 100 feet (30m) away! In addition, while cave diving you often are exploring, laying line, taking pictures and/or surveying and sketching. With all of these tasks, it is VERY easy to lose track of something important like gas supply or the location of your buddy!
So what about the mind? Obviously, you need to be completely focused on the dive to survive. One of my survival tactics was to abort the dive if I found myself thinking about anything other than the dive (so far it has worked). At the same time, intense focus blocks out the rest of your life and I often found that when I had a great deal of stress in my life, cave diving was a break. The intense focus was actually relaxing because it meant for that period of time I was NOT thinking about everything else.
Claustrophobia is often a problem in cave diving (and, for some, even open water diving). There is a huge difference between swimming through a subway-sized tunnel with huge lights and clear water and wiggling through a space too small to take a full breath in zero visibility.
The secret about mental limits is to be very aware of them. You need to respect your feelings. If you want to expand your comfort envelope, push to the edge of where you are just starting to get uncomfortable and stay there for several dives. Over time, you will find the limit moves out.
At the same time, pushing your limits can be very dangerous. Lots of cave/technical divers are trying to prove that they are not afraid, when in fact they are. One of my dive buddies had a near death experience on a dive. After that he was always trying to show that he was not afraid and on the more challenging cave dives he was so focused on not appearing afraid that he was dangerous, since he was not paying attention to the details of the dive. He backed off to less challenging diving and has done fine.
So what is the take away about the mind and cave diving, or technical diving, or any other challenging type of diving? You have to be able to focus exclusively on the dive. You have to be able to keep track of several variables simultaneously. You have to maintain a level of arousal appropriate to the situation and a level of arousal appropriate to a high level of performance. You have to be very aware of your comfort level and your performance. If anything is not working well, abort the dive. My first cave diving buddy and I had a rule: one major problem on the dive and we would abort the dive and go to the pub for a beer. Many diving fatalities happen when people push on after two or even three significant problems have already happened on the dive. When problems are happening, clearly your mind is not up to the task that day. Best to recognize this, and go for a soda.
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