There’s a thread going on one of the last remaining message boards that isn’t on the dark-web about the relative safety of cave diving against open water diving which reminded me of something that happened during a class a while ago. Most of the discussions falls into two camps: 1 - Cave diving is obviously dangerous, people who do it might be well-trained and all, but it’s still way more dangerous than open water. 2 - Cave diving bears more risk (rather than danger) than open water, but risk can be mitigated; neither one of them is inherently more dangerous, but rather any divers engaging in either can BE in more danger. And then there’s a third camp who is just yelling that everyone is stupid. Because it’s the internet. I was teaching a full cave course to two very capable divers. The class had been going exceedingly well and we were nearing the end. “Nearing the end” roughly translates to, “obscenely unlikely failure cascades that have the divers limping out of the cave, hopefully with a smile on their face as they have finally wrapped their head around the point that as long as everyone is breathing, anything else that happens is simply an inconvenience.” The dive itself had been going well. Even as one diver lost one backgas regulator then - lo and behold - the other exploded into a noisy roil of bubbles as well. The two divers calmly established position on the line. They initiated a gas share. The second “failed” reg was troubleshot and determined to be unfixable and quieted. They took up proper exit positioning and started their swim. NOTE: For non-cave divers - a restriction, in this context, is a passage that is too small for two divers to move through easily side-by-side. Everyone has an image of cave diving as constantly crawling through tiny passage. The reality is that there are plenty of passages you could fit a nuclear submarine through and, generally, Intro to Cave Divers (the level preceding Full Cave) are limited to much larger passages. It only gets wiggly in Full Cave. And, even then, only if you’re into wiggly. This was nearing the end of a full cave class. Their exit was not a subway tunnel. In fact, there were two near-back-to-back restrictions that would require them to fall into single file and do a little wiggling and a little remembering of shapes to get through blind. Oh, right… did I mention they’re blind, now, too? All those bubbles from the failed reg DESTROYED visibility for some ways downstream. (In reality: I handed them each a blindfold to put on over their masks.) The exit started just fine. They communicated falling into single file at the first restriction and slid through it, past the jump spool they’d placed. At the second restriction everything went pear-shaped. The lead diver - the out of air one, breathing on their teammate’s 7 foot hose - was obviously distracted. Struggling with their buoyancy. No longer feeling the restriction to determine a good profile to slide through. Nor were they communicating with their teammate, still hanging onto an arm, not yet having reached the restriction themselves, but trapping the OOA diver between a body and a rock wall. There was no sense of actual panic or even pre-panic… it was just a lot of grumpy annoyance as they tried to simply bully their way through this goddamn hole in front of them. Both got minority entangled in the guideline once or twice as, each blind and trapped in their own heads, they tried to work out how to get moving again. Both even lost contact with the guideline at least once; this is a HUGE no-no when blind in a cave. Because without constant contact with that line if you can’t see you are now blind, in a cave, and completely lost. Granted, given the narrowness of this passage it wasn’t hard for them to find it again… but I knew it was something we were going to talk about on the surface. Here’s one thing about my training philosophy/methodology: As long as you’ve got enough gas left in your tanks to safely get yourself and a buddy out of the cave… I’m just gonna let shit play out however it’s going to play out. You get yourself into a mess… get yourself out. Once the ball has started rolling I’m simply there to offer critiques later and to make sure you never dip past a minimum gas reserve. A minute passed. Then two. Then five. Neither diver had moved an inch. I stole a look at the donating diver’s pressure gauge… they were only a few hundred PSI from minimum; the OOG diver was hoovering the needle down in their frustrated struggles. I determined to cut the drill at minute ten. Somehow, miraculously, at minute nine they popped through the restriction like the cork from a a bottle of cheap Asti at a bachelorette party. The passage opened up into quite big almost immediately afterwards and I took the opportunity to have them remove the blindfolds and completely end the drill, with the “OOG” diver going back to their own still abundantly plentiful gas supply. We would have a lot to talk about at the surface. And as I worked on collating my thoughts into a meaningful debrief during the exit swim I started to notice… The closer we got to the exit, especially as we started to get shallower and shallower… the diver who had been “out of gas” kept trying to vent buoyancy from an already empty wing. Their normally near-perfectly flat trim was all out of whack as they seahorsed along through the cave. Like one of those deep focus movie shots in Hitchcock movies I realised what had happened. What had caused everything to go from leisurely and fun to utterly, potentially fatally, fucked. I glanced between their doubles to confirm their non-existence. As soon as our heads broke the surface I asked, “You forgot your weights?” “I forgot my weights.” Being underweighted underwater is a frustrating feeling. That struggle to stay down, to stay with the group, to stay off the ceiling, to stay out of surface chop… whatever the environment, it’s frustrating and uncomfortable and the feeling of the lack of control can, itself, be so distracting that you start to miss even actual, clear and present threats to your safety. Such as a rabidly diminishing gas supply. “How much gas would you both have needed to get out from that spot in the cave?” I asked. They did a little joint mental math based on time, distance, and breathing rates and came up with… I dunno, it was a while ago, let’s say, for the purposes of the story… “1400psi.” “Right. And did you see how much gas was left in the donating tanks when the drill was cut?” They both shuffled their fins in the water and admitted no one looked. “I did look,” I said, “You had exactly 1400psi. Which means that as long as you didn’t encounter one single problem for the entire rest of the way out and moved quickly and cleanly the whole way you would be breathing the very last of those tanks the moment you hit the surface.” Because of weights. A problem that didn’t present itself until more than halfway through the dive when the aluminium cylinders started to lose their negative buoyancy as the weight of the nitrox inside had been exhaled into bubbles. No error in judgment. No lack of ability. The danger came from a perceptual narrowing caused by a moment of perfectly human absent-mindedness during the dive set-up two hours earlier. I admit, as an instructor, weights are something I’m only vaguely aware of if, and only if, I’m standing right there while people are putting their stuff together. I’m watching constantly for things like a deployable long hose and avoidance of dangly entanglement hazards. Weights are just… there. And most everyone remembers they forgot to put them on JUST as their backplate wing nuts are getting tighter down. I don’t know that I’ve ever even heard divers checking eachothers’ weights during a predive (those divers that bother to do a predive at all). But in this case lacking them was something that could have killed two people dancing at the very razor’s edge of their safety margin. Yeah, it was a class. Yeah, they had someone not-blind monitoring their gas supply for them. Yeah, nothing was actually broken and I had snuck up on the “OOG” diver and confirmed all their valves were turned back on after they had turned them off to emulate failures. There were buffers and buffers and buffers built into this entire exercise. But I’ll tell you what: for the remainder of our time together both divers triple-checked that their weights were in place every day as they assembled their gear. I venture to say they’ll both continue to do so for the entirety of their diving career, whether it’s caves or wrecks or 30 foot reef. One of those mistakes you’re forever grateful you only made once and while the bumper-rails were up. Which brings us back to the question of relative safety between cave diving and open water diving? My answer: neither is safer. Safety implies an environment where injury is unlikely. And the truth of the matter is that going into an alien environment while wearing life-support equipment designed and built by weirdos and misfits is not safe. There are risks. Risk, however, can be mitigated. The risks in cave diving are greater, as evidenced by the story above. Forget a weight in open water… you wind up on the surface. Forget a weight in a cave, you can wind up pinned to the ceiling or struggling during your entire exit, using more gas than you’d planned for, and… well… not make it out. Higher risk. In cave diving we mitigate that risk with training. With practice. With redundancy and proficiency with that redundancy. By having a forgetful lapse in the relative bouncy-castle of a class where it can be parsed and analysed. By trusting that no worthwhile instructor would send a diver into the overhead without the proven ability to both self-rescue and be an effective team-mate. In open water that risk seems, industry-wide, generally mitigated only by having a divemaster there to bail dumb-dumbs out. The quality of those divemasters themselves being… ambiguous. I think it could be generally agreed that if you’re given the choice between someone who just finished a three-day OW course in some factory farm somewhere or a trained technical diver as an insta-buddy… who are you going to pick? Yes, yes, yes… I know there are some people who take to diving like a proverbial fish to water; and I know some tech divers are insufferable gits you can’t help but hate on sight. But really… all things being equal… who would you trust to have your back more in the water? Who are you going to be able to have a comfortable, safe, long dive with?
“Safe” is too dubious a term. What I think of as a perfectly safe dive - possibly to the point of mind-numbingly boring - might be the thing of nightmares to someone else. What someone else thinks of as hum-drum may seem batshit insane to me.
It’s not that open water nor caves nor shipwrecks nor depth is “safe” or “dangerous.” It’s the divers who can demonstrate training, ability, and judgement to put themselves in situations where the risk is either mitigated or multiplied. The best we can do, in the end, is try not to be a risk multiplier. Seek out good training. Practice and dive as often as possible to that level, whatever level that may be. Push your boundaries slowly, sensibly, and with the help of a good team/buddy/mentor/guide/instructor. Know your kit backwards and forwards before adding more kit; be able to put it together with your eyes closed. Have a good plan. Plan your dive and dive your plan. Do a briefing and a debrief. And double-check that your weights are in place. Maybe there is something to BWRAF after all?