Updated: Jan 26
“This is your captain speaking. Thanks for joining us on this flight from Atlanta to beautiful Rio de Janeiro, we hope to make your trip with us a comfortable one. On a personal note, I’m pleased to be taking you. You see, I just learned to fly a crop duster a few weeks ago, but my instructors said I’m pretty good at it, so I enrolled in the next class immediately afterwards and… well… here I am!” Be honest. You’d get off the plane, wouldn’t you? But, of course, such a thing can’t happen, so it’s just a hypothetical. The gravity of becoming a pilot on even a single-prop plane (much less a passenger jet) is strict and codified. What’s more, there’s something intuitive about not flying up in the fucking sky without a whole lot of training. It’s an alien environment, a place we don’t belong. Just being a passenger in the sky is stressful, much less being in control of the machine that takes us there. Underwater caves are also an alien environment. The level of risk involved in being in such an unforgiving place can not be overstated. Mitigated? Yes. Not overstated. But, when people are already divers - when people already have a good bit of exposure to being underwater - people don’t intuit the danger and the need for specialised training the same way they might for piloting a 777. It’s as if every diver has a licence to pilot a Cesna, and think, “How hard can the flight from New York to Hong Kong really be?” Every few weeks I have the same sort of conversation with a prospective student. “I’d like to come down for a week or two to do Intro and Full.” (Occasionally Sidemount is thrown in there, too.) And then Nelly or I have to sit down and write a long email to them about why this is a terrible idea. —————————————
The limits vary a bit from agency to agency, but generally you can see the limits of the two levels of training here:
Without getting too mired in the details or breaking each of these down point by point, suffice it to say that the reasoning behind defining more stringent restrictions for “Cave Diving 101” is to impose a safety buffer on the diver. Assuming that someone has earned an Intro certification they have just learned the basics… enough to keep themselves and their team alive for an unchallenging cave dive (if such a thing as an “unchallenging cave dive” exists). The one specific restriction that bears the brunt of that safety buffer, and consequently deserves a bit of attention for its efforts, is the rule of sixths vs. the rule of thirds. Let’s say a diver is wearing a set of double AL80s (yes, Mexico is making me soft… those are just the tanks I think of automatically now). They’ve got 150cf of gas on their back (don’t argue, just go with it). Following the rule of thirds - one third in, one third out, one third in reserve - they can breath 50cf in, which will require 50cf out, leaving 50cf if a team member has a problem. Plenty, right? Unless, of course, if something goes wrong. If they wind up sharing gas with a team member with a matched breathing rate… and happen to have a problem at the deepest point of penetration… then they’ve got EXACTLY enough gas to get the both of them out safe. 50cf in, 100cf between the two of them on the way out, and they hit the surface breathing the very last gasp out of their shared gas supply. Same scenario following the rule of sixths: 25cf on the way in… catastrophic problem at the deepest point of penetration… 50cf required to be shared by both divers for the way out… surfacing with 75cf still left in the tanks. Or, more likely: - 75cf extra to deal with elevated heart/breathing rates. - 75cf to deal with unfamiliar cave (because our divers are new and haven’t had the time to really learn all the twists and turns yet). - 75cf to deal with getting tossed around by flow or getting bumped by their buddy’s tanks, because they’ve only practiced gas sharing a few times in class. - 75cf to deal with the bad viz they kicked up or got caught on the ceiling during the air share, because their instructor was (for some reason or another) not really insistent on absolute precision at this level. - 75cf to deal with any one of the other zillion unanticipated factors. And all of this is to say nothing of the subsequent distance limitation of sixths. I’ve got some students this week with absurdly good breathing rates. They just about match my own at something in the range of .35cf/10L per minute. With this breathing rate, at shallow depths, it’s easy to draw sixths out for up to 40+ minutes. Swimming at a comfortable pace that could put us more than 1000’/300m into a cave. That is a long damn way from home.
“In moments of great stress, every life form that exists gives out a tiny subliminal signal. This signal simply communicates an exact and almost pathetic sense of how far that being is from the place of his birth.” - Douglas Adams, Hitchhiker’s Guide to the Galaxy Let’s take new cave divers, buddies who have just completed class a few months ago who, immediately on finishing their course, got on a plane and went back to their normal lives. Each weekend on the dive boat or at the quarry they boasted to their friends about having completed cave training and how tough it was. Now they've returned to cave country and are on their first post-certification cave dive. They’re a little rusty, but it’s all coming back. And suddenly, there is an eruption of bubbles from a second stage. They had their regs serviced special for this cave diving trip, but frustration with the service tech is not really on either of their minds as the diver with the freeflow starts turning off the affected valve as they’ve been trained. It’s not as smooth as it was in class all those months ago, but the training comes rushing back. Think our divers’ heart rates are going to go up a bit? Think, now having suffered a legitimate failure, with no instructor there to bail them out, they aren’t going to be ACUTELY aware of just how far from home they are? Think they’re going to be grateful for the additional safety buffer the rule of sixths has afforded them? Same divers in an alternative reality:
They did both their Intro and Full back-to-back all those months ago and have the same problem. But they aren’t 1000 feet back in the cave. They’re 2000 feet back in the cave. They paid for and passed the training, and they’ve paid all this money to travel to cave country… of course they’re going to dive to thirds to get some really good dives in. Now these mirror universe divers have just suffered their first legitimate failure with no instructor to bail them out AND they’re on the razor’s edge of having enough gas to get home. How much you want to bet that home, in that moment, will feel like it might as well be on the other side of the galaxy. What do you think that feeling is going to do to heart/breathing rates? Oh, and our mirror universe chums were also terribly proud of the several jumps they had made along their way into this small, crumbly section of cave where they had the failure. ————————————— The key point behind breaking cave training into steps is to allow people to learn the environment in its less challenging form with as much of a safety buffer as possible. To give people breathing room… pun only partially intended. The emotional, psychological, physiological, and practical differences between our two failure scenarios above is leagues apart. And those intervening leagues should be made of experience. There is only one agency which springs to mind that explicitly requires a number of cave dives between the first and second stages of training. Maybe more agencies should follow that model. Sure… there are the outliers. There are the odd divers who have decades of experience who have always worked hard on precision control, who naturally have the talent and the right mindset and could become Full Cave divers in a week. They exist. I mean... so do people who can do polynomial calculations in their head… they’re out there… but they’re shrinkingly rare. You are almost certainly not one of them. We have to accept that there are outliers on the other end of the spectrum, too. People who may have been diving at the intro level for years with dozens of dives and they’re still terrible divers.
If there was a dive number prerequisite for the prodigy then... oh drat, they’d have to endure a bunch of intro-level dives before they were allowed to enroll in the more advanced class.
For the latter, not-such-a-wunderkind… let’s just hope some instructor or mentor is brave enough to have an honest conversation about their limitations. For the rest of us, who loiter around the middle of the bell curve, mandating some experience between Intro and Full is worthwhile. Get comfortable with the places and the procedures. Get used to how it feels to be in front, middle, and back. Refine your light discipline and communication. Get used to both certain types of and specific buddies. Plan your own dives. Personally, I don't have a dive number prerequisite. Nor do I say categorically, "Intro and Full can not be done in a single visit." I accept that the world is a wondrous place full of diversity and surprises; so there may be outliers. But they're damn rare... and unless we've already spent a ton of time in the water together in the past so that I know exactly what you're capable of, I am not going to accept you as a zero-to-hero student. As an instructor I feel in my bones that it is critical to have a soft-start to the psychological stresses of being in an underwater cave before subjecting yourself to the much more extreme psychological stresses of being REALLY REALLY FAR into an underwater cave. Without lots of non-training dives after earning a certification people don’t have enough of a chance to process and really integrate what they’ve learned. Even more than non-training, at least some of those dives should even be unguided.
To earn a certification, people should have demonstrated the ability to take care of themselves and their team, to plan and execute dives without the safety net of an instructor. And, no mistake, having that safety net removed does and should present a psychological stress in and of itself. (I very clearly remember the feeling of the exact moment Nelly and I went diving only the two of us, without that safety net.) Comfort enough at the basic levels of any endeavour can only come with time. And patience. ————————————— The truth is that I don’t trust an instructor who says, “Sure, I can get you through Intro and Full in a week” or two weeks, or three. Inside of a month is pushing it. I question their judgement as an instructor. I question the comprehensiveness of the skills as they teach them and have their students practice them. Our mirror universe students above… the ones who now have to navigate past a couple of jumps on their way home after the free-flow… how well-laid are those jumps? How many times have they actually practiced their line-work in class?
When an instructor thinks it’s an OK idea to have compressed that much training into that short a time… what are their thoughts on line-marking protocols and are they actually appropriate? I recently turned down a student who was insistent on powering through both classes in a single visit. As part of my last email to them I reiterated my concern by warning them away from any instructor who accepted them into a back-to-back training schedule. I warned that such a person was either someone who was either comfortable taking their money in the full knowledge that the student would fail… or was the sort of instructor who didn’t recognise their own limitations as an educator. In either case they might be willing to issue a card, but substandard training in support of the certification. Nowadays you can barely spit in a dive shop without hitting a cave instructor. This is wildly different from the early days, when cave diving was this arcane practice alike to black magic or pastry baking. To become a cave diver was to first find an instructor, which was no easy task. Then you had to convince the instructor that you were really worthy of becoming a cave diver by standing outside the gates to Peacock Springs for three days and nights without food, water, or sleep while the instructor hurled insults at you and the locals hurled empty beer cans as they drove by. OK… I'm exaggerating that last part. But not by much. Training itself was not as formalised. There was no week-long class… there were months and years-long mentorships. Students frequently didn’t make it more than 100 feet into the cave for dozens and dozens of dives or even see a main line for ages. Yeah, this model is obviously terribly dated. Those divers were generally folks who lived near enough cave country to go dive there every weekend to complete such a laborious progression. Nowadays people want to come from all over the world for all sorts of reasons. Modern travel situation notwithstanding, vacation time is scarce. So training must be succinct. But succinct shouldn’t suck. Students still need to be aptly prepared for the challenges of a high-risk activity. No one should pass any level with “Meh… that’s alright enough, I guess.” Nor should they be expected to remember what used to take months and years to master in only a week. —————————————
When someone suffers their first failure a couple hundred feet from the exit, along a single line through Holland Tunnel-sized cave, with unlimited viz, and a massive gas reserve it can barely be compared to someone suffering the same failure several thousand feet back, past multiple navigational decisions, through a couple of grinding, zero-viz restrictions, and at the very limits of gas planning. The former diver should be able to manage the problem after having just earned an Intro cert yesterday. The latter should have a good deal of time and a good number of dives in their log before even working their way to the place on the map where the failure happens. As a wiser, more experienced diver their first thought, on hearing a regulator explode behind their head, should be, “Oh, come on, what the hell was that? What a bloody inconvenience. Better let the team know.” The familiarity and comfort that affords that level of mental control will get the team out safely. If the diver’s first thought is, “AAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHH FUUUUUUUUUUUUUUUCCCCCCCKKKKKKKKK!!” it is just as likely as not that someone is going to drown to death in a cave. Then the authorities need to be notified. Then recovery divers need to be deployed. Then families have to be told. Tears are heavily shed. Everyone even remotely involved has psychological scars for the rest of their lives. Access to caves may be closed down. Stories show up in the papers about how dangerous cave diving is. Public opinion of the cave diving community suffers. Sorry… got off on a bit of a tangent there. I get pretty pissed off by, “It’s my life, I would wouldn’t mind dying doing what I love, and besides it only affects me.”
————————————— I suppose this entire post has been a bit of a tangent. Don’t take Intro and Full back-to-back, space them out, do a little cave diving in between the two; you get more diving that way and it will make you a better, safer diver. That’s the thesis of all this. This has all been focused on Intro/Full, but the value of patience and slow progress holds true across the diving spectrum. Whether it's CCR mod 1, 2, and/or 3. Whether it's Open Water courses or wreck diving courses. It holds true even past Full Cave, as pertains to DPVs and stages and rebreathers. All the fancy toys are so much more accessible and everyone is in such a rush to use them because they are awesome. (And, yeah, they are awesome… but not quite as awesome as continuing to live.) There’s no rush. The caves have been there for hundreds of thousands of years; they aren’t going anywhere. So if you want to see the caves: take your time, swim slow, look around, take it all in. There is more than enough to see at the Intro level before you start bumping up against the limits of the training and absolutely need to move on to Full. I have often said that if the Ginnie gallery was 2000 feet back it would be the most prestigious dive in the world… but because it’s only the first 200 feet of cave no one ever even looks at it while they scooter past. Or maybe you just wanted to learn the skills of a cave diver. Line-work, buoyancy and trim control, team awareness and communication, etc. If so… why would you need to rush on to the Full Cave level? You can learn these things in Intro. In fact, if you focus only on Intro then your instructor will have much more time to focus on the things that you are actually interested in learning instead of trying to rush through the million skills required. And, finally, if your priority is not to see the caves, but rather just to have a fancy-pants card to show your friends at parties… there are other ways, far less risky ways, to earn gold stars to brag about. Learn a language. Create a really good meme. Memorize the succession of all the Roman emperors. Start growing a bonsai tree. I dunno… do… something that’s not cave diving and, therefore, probably dumb, but a whole hell of a lot safer. I’m going cave diving. Because I do like looking at the caves. Even the parts that are 200 feet back along the main line.