No. The point is that over the past decades, people have learned how to do dives safely, whether in caves or in open water. We are still learning, but we have learned a lot. We have established certain norms for doing such dives. Violating those norms reduces the safety margin and increases the risk.
True, but at the same time, we've also had a moving target: in addition to training for 'better' ways, we've also had the margins on (real or perceived) limits moved too, which in some cases were much more likely motivated by the perspective of reducing potential liability.
A classic example is in bottom time: good luck in actually finding a publication that quantifies the actual DCS risk (
bootleg), and even though the classical Navy Dive Table permitted 25min NDL @ 100fsw, dive computers have had progressively shorter times. For
example, the Dacor Omni from 1993 permitted a 20 minute NDL on a 100fsw profile. Compare that to today's computers...they all have shorter maximum permissible times...some are now as little as 12 minutes IIRC. While it is certainly not a bad thing to be conservative to bolster safety margins, the problem is that lacking any published quantification of a profile's estimated DCS risk profiles, the numbers don't have any providence: it is inevitable that the numbers used have a strong dose of lawyer-based liability insulation built in.
Diving beyond your training means that you do not fully understand the risks you are taking, you do not know the safety measures you are missing, and you do not have the training it takes to deal with emergencies that should be anticipated.
Deliberately ignoring your training means that you understand the risks you are taking, you make a conscious decision to miss one or more safety measures, and you hope your training will enable you to deal with an emergency that you anticipate could happen because of that decision.
It looks like a pretty big difference to me. Of course, people who have not been trained for this sort of thing don't realize how much there is to it, so they have trouble seeing the difference.
I agree with where you're going, but I think that the condemnation of the second possibility is a bit simplistic. The problem starts with how formal training has been whitewashed into "Do this, don't do that" without the underlying depth of science, which means that the formal training has limited itself in its applicability. Once again, we can see where such an approach can strategically limit the potential liability exposure of the trainer. But by this choice to avoid frank & quantified discussions on risk, the community hasn't been equipped with the knowledge or the tools to know how to assess risks, particularly which risks are worse than others. When the inevitable incident happens, the diver is left in the lurch of not clearly knowing which choice is the 'Lesser of Two Evils'.
Please note that this isn't to say that the diver will always make the right choice, or that that taking the risk-taking will always pan out favorably: they won't. However, the facts remain that divers still die even when they're faithfully following all the formal rules, too.
So what I see as missing is a third option of basically one of "Informed Consent" in modifying (not necesssarily "missing" a safety measure) a standard dive practice. While the assumption is that safety margins will always be narrowed, it isn't necessarily so: any of us who have done a 7 minute safety stop when the SOP calls for 3-5 minutes is thus "Guilty" of modifying standard practices. What can ... and does ... occur over time is that the knowledgable diver will learn on his own where the defacto safety margins are irrationally "fat" in comparison to other objective risks, to which they may choose to act accordingly to improve some aspect of the performance of their dive without the risk actually being degraded.
Here's the difference.
In the worst case scenario, a diver at 60 feet with no overhead environment diving within NDLs can go straight to the surface with no serious threat of a problem.
A diver who has gone deep enough and/or long enough to incur a deco obligation is at increasing risk of DCS or drowning in the same situation should he or she exercise that option. If Opal and Gabbi had run out of gas at 60 feet, we wouldn't even know it happened. They would be happily diving today. Instead, they ran out at 200 feet, and we have a tragedy.
All you're really doing is illustrating that mistakes are a bad thing and some mistakes are harder to recover from than others. Had the proverbial diver ventured inside an overhead at 60fsw, become lost and gone OOA, they would be just as dead, without the 'Depth Bogeyman' baggage.
Yes, there is a 'Slippery Slope' when it comes to correlating pure depth to risk, except that an extra foot at any depth isn't by itself be a killer. If it were, then OW divers would instantly die as soon as they go to 61fsw, with AOW divers spontaneously combusting at 131fsw. The real problem with the whole 'Deep Air' bit is that the risks are both continuous as well as functionally "discontinuous" because of other variable susceptibility factors...and that variability is really where the risk concern resides.
On the one hand, I philisophically don't have too much of a problem in accepting a diver ... who has sufficient knowledge/background so as to be in a position of "Informed Consent" ... to operate at a different (eg, lower) safety margin than standard recreational-centric practices. It doesn't matter if we're talking about solo diving, dead boat diving, deep air diving, or cageless shark diving: in a manner of speaking, "risk is risk".
On Narcosis risk specifically, my biggest concern is how does one really figure out what represents adequate applied knowledge so as to make for an honest "Informed Consent" risk assessment? For example, we can talk about there seemingly being some evidence of diver acclimation to Narcosis impairment, but to this very day, the absolute worst Narc I've ever had hit me at an "incredibly shallow" 60fsw...and that was on my last day of two weeks of continous diving to depths averaging 1.5x deeper and which were occasionally 2x as deep. This experience also taught me something quite cynical about those arguments of 'Acclimation'...there's always more variables than the benign use case.
Finally, what I've been concerned about for several years now is the advent of Mix and Tek training resulting in an environment which functionally encourages divers: they become more prone to engage in deeper, higher risk profiles before they've gotten 500 dives under his belt. Heck, there's probably some certified cave divers who don't even have 100 dives yet.
Frankly, what I have my reservations on is the suitability for anyone to "Fast Track" into the more difficult disciplines even with the gear, mixes and training ... there's a lot to be said about just racking up "Seat Time" before moving up into a more challenging (ie, contextual risk management) situation, which sometimes is reflected in "Min # Dives" entry requirements for some levels of training. The devil is in the detail for how this could (including should) be applied to the paradigm of the 'Vacation' Rec diver who's looking at a warmwater depth excursion. Sometimes, it is merely just for the purpose of having a macho response to the "You're a diver? How deep have you been?" question.
-hh
