A_Person

Sure :-)

Objectively speaking, the most dangerous moment I've ever had scuba diving was in a straight-sided sinkhole, with no overhead environment at all, doing a refresher course, for the first (most basic) level of cave diving, after a few years off! Some unexpected things went wrong, and I suddenly realized that I was seperated from the group, 40 meters deep, silted out, tangled up, and the scary part: hyperventilating like crazy, and absolutely about to panic. It took every ounce of 35 years of diving experience to keep it together, which I only just managed to do. It was amazing how quickly it went from totally cool, to totally about to panic - it felt like only seconds. It taught me that I'd got MUCH TOO COMPLACENT, and needed to refocus things. This was quite a few years ago, and I felt the effects for several years afterwards.

A later expeience was when I went through a small restriction that I and my buddy had been through several times before. For some reason, my buddy couldn't get through this time, so I turned back - and couldn't get out! Try as I would, it just wasn't happening. I'd go in, get stuck, back out, check my gas, close my eyes, wait for my heartrate to go back down, then try again. After maybe 10 minutes trying, I eventually managed to wiggle out. Now I wear my tanks "side mounted", so I can unclip one or both of them to reduce my profile.

A few months ago, a buddy and I were diving with another pair. We were in front, they were behind. Then they disappeared, so after waiting a while, we turned back to see what had happened. I then found that the tunnel we were going back through, was completely silted out (perhaps 6 inches visibility), and the fixed line seemed to disappear under a rock, into the ground! I couldn't find where it came back out. In our part of the world, you're hung drawn and quartered if you touch the cave - anywhere - at all; but stuff that, I heaved that big sucker off the line, which happily sprang back into place, so we continued into the murk!

The last two examples might seem a bit scary, but those kinds of situations are just part of the learning process in cave diving - every competent cave diver is equipped and trained to handle such things. The first example, mundane as it may sound, was the one that really scared me.

Shall I book you a place on the next course? :-)

[edit: spelling]

The statistics on the page you reference come solely from UK divers, and US divers "insured by DAN"! That's not much of a cross-section. And the relevant link: [14] "UK Diving Fatalities Review" doesn't work, so we don't know how they estimated the total number of dives per annum - a notoriously difficult figure to gauge, as many other diving safety reports have admitted.

As for "cave diving is even more dangerous", I assume you mean compared to recreational diving. If so - says who? The whole thrust of my previous post, which I illustrated with copious details, is that cave diving is probably not more dangerous than various other daily activities. You're welcome to disagree, but what are your actual reasons for doing so?

> And what happens when the fixed line breaks, somebody kicks up a little silt and you get disoriented as well? (Which is exactly what happened in the article.)

It's not unknown for fixed lines to break. Generally you'd tie-on a spool, and swim forward in the correct general direction until you found the line again. But if the other end had been pulled right out, you could be in trouble! In the system I referred to, there's a spot where the farmer who owned the land above, drilled down into the system to get some water. By a chance in a thousand, he drilled directly through (and severed) the fixed line in one of the main tunnels!

As for silt, a key part of cave diver training (certainly in this part of the world) is being able to perform all skills in a total blackout (whether from silting, loss of light, or whatever). This includes sharing gas, donning and doffing tanks, navigating restrictions, following the line, finding a lost line, and so on. That's just "part of the job", as it were.

I'd like to address the false assumption in this thread that cave diving is more dangerous than driving a car!

I cave dive on a regular basis with two other guys. We've dived together as a team for nearly 10 years. I'm late 60s and single, the second guy is 50s and has a partner but no children, and the third is early 40s with a six-year-old, who he has every intention of seeing grow-up into adulthood.

We often dive in a system comprising a complex maze of 8kms of underwater tunnels. Some are large, and would fit several divers across, but some are small, and you can barely squeeze through. The only entry to and exit from this system is a small pond, about 6 feet across and 4 feet deep, just big enough for one person to get in at a time. Then you scrunch yourself up, and drop down through a slot to enter the system.

We'd generally go about 700m into this system, making up to 13 seperate navigational decisions (left? right? straight ahead?) which we have to reverse precisely to get back out at the end. This is all completely underwater, there's no air anywhere except for two air pockets hundreds of meters apart. As I like to say, in cave diving there is no UP – there is only OUT!

It all sounds pretty dangerous, right? Wrong.

NAVIGATION. The whole system is set up with fixed lines, each of which has a numbered marker every 50m or so. Before each dive, we consult the map, and plan exactly where we're going to go. I commit that plan to memory, write it down on a wrist slate, and also in a notebook which I take underwater. All three of us do this independently. Underwater, when we come to a junction, each of us checks the direction to go, then marks the exit direction with a personal marker. If anyone makes a mistake, for example, turns in the wrong direction, or forgets to leave a personal marker, the other two pick that up immediately. On the way back, when we get to each junction, each of us checks that it's the junction we expected, and we can see our personal markers. Each individual's markers can be distinguished by feel alone, so we could get the whole way back, separately, in total darkness, if we had to. So the odds of us getting lost in the system are very low.

LIGHT. These caves are absolutely pitch black, so naturally you need a torch. In fact, nine torches! Each of us individually has a multi-thousand-lumen canister battery light, plus 2 backup torches, each of which would last the whole dive. I could also navigate by the light of my dive computer screen, and I'm considering carrying a cyalume chemical lightstick as well. So then I personally would have five different sources of light, and we'd need 11 sources of light to fail before the team would be left in the dark. The risk of this happening is basically zero.

GAS. Each of us has two tanks in a fully redundant setup. If one side fails, we just go to the other and call the dive. In fact, our gas planning allows one diver's entire gas supply to fail, at the point of maximum penetration, and either one of the other two divers could get that guy back, plus himself, without relying on the third diver at all. However, gas is certainly a limited resource underwater, so it's always on our minds, and all three of us will turn the dive as soon as anyone hits their safety limit.

There's lots more equipment involved, but let's leave it there for the moment, and turn our attention to...

DRIVING! Each of us lives >400 km away from that system. So there and back is a five hour drive. During that drive, you could fall asleep and run off the road; have local fauna run out in front of your car; get head-on crashed by drunken drivers, and so on. Several of those are external risks that are not under our control.

So the simple fact of the matter is this. Our cave dives are almost certainly SIGNIFICANTLY SAFER than driving to and from the dive site! The cave dives carry significant potential risks, but most of those are mitigated with proper training and equipment. Whereas there's not much I can do to stop a drunken driver running head-on into me.

Certainly there are risks like tunnels collapsing and blocking the exit. But statistically, I'm sure that those are orders of magnitude less likely than having a heart attack, or falling over and breaking your neck.

Hope that helps :-)