Diving to 200' and Beyond

[Colliam7]

** MOD POST: **

Everyone - let's keep this thread on track! Agency-bashing, name-calling, etc. is unnecessary, irrelevant to the OP's initial questions, and counter-productive. If you think a certain practice is not a good idea, or if a certain practice is something YOU would not do, fine. Say so, and say why. The thread is about diving to certain depths (solo, as it happened). Please keep posts focused on the topic.

 

[PfcAJ]

My personal vetting process is to get into some interesting situations close to the door. Maybe a passage that requires finess to move though cleanly, or one that requires some line work. Maybe even one that's dusty and almost certainly will result in an on the line exit for a bit. Maybe a dive that involves a bottle drop and pickup or two. Yanno, dives that actually require some skill to pull off. All of these things can be accomplished on dives that don't involve being hours into the cave.

There's still a human element to diving, no matter how robust the training or procedures are. Peoples' personality comes out in adverse conditions. Id rather sort all that out close to the door. If you don't have what it takes 'upstairs', I don't care what class you passed.

 

[Storker]

What is a stupid depth for air?

As an initial estimate, I'd say "the depth at which the diver becomes stupid on air". Which depends on the individual diver's neurochemistry, the individual diver's ability to realize their own stupidity (which varies quite a lot), the individual diver's experience in diving while stupid and the individual diver's tolerance for being stupid while experiencing the unexpected.

For me personally and in my local diving, I notice the onset of stupidity when I approach 30m, so my personal "stupid depth" is somewhere a little beyond 30m. Besides, unless one is equipped with a solid redundant supply of gas, bottom times become stupidly short when the diver passes some 30-40m. YMMV of course, but it's pretty well recognized that one isn't the best person to evaluate one's own stupidity (insert Dunning-Kruger reference here)

 

[beester]

There's still a human element to diving, no matter how robust the training or procedures are. Peoples' personality comes out in adverse conditions. Id rather sort all that out close to the door. If you don't have what it takes 'upstairs', I don't care what class you passed.

Point is that someone who has passed a full cave cert from a good instructor should be able to do what you are "testing" (restrictions, fin-technique finesse, smoothness in staging, awareness to team, good solid communication). The 'upstairs' part is much more difficult to evaluate I think... and you never really know. All the above are just indicators. But this you can see on the first dive as well.

It's true that we are humans... and personally I have called a dive with a diver who was C2, because it didn't feel right... there was no smoothness, communication was not good. But I called that dive in the first 30 minutes.

If it's a MX dive (what we were discussing) there are certainly dives in my book which are possible to do in that context (never met... and after discussing the plan... just go and dive). But maybe I'm victim of normalisation of deviance (= cut corners).

My personal depth on air 15 years ago = 50-65m
My personal depth on air now = 40 m in benign tropical conditions (no deco, no current, nothing special) and 30m for everything else...

I'm not making a comment on the lady doing these dives. In the end everybody makes his own risk-analysis and decision. However to use an analogy: 50 years ago cars were produced without seat-belts. They are available now (progressive knowledge). If she decides not to drive the car without a seatbelt that's her decision. But it's not because she got her permit 50 years ago or because she never had a car-accident (needing the seatbelt) that it's safe to drive without it.

 

[dumpsterDiver]

Why are people being allowed to go off topic and discuss a single tank dive? It is quite clear that she has two tanks?

Since I have no tech training and don't know much about trimix, I would like to hear a reasonable discussion about the described practice of trimix deco using air for the stops.

 

[Stoo]

That sort of diving was pretty common when I began diving, even here in Tobermory, where you have the added "challenge" of freezing temperatures. My first 200' dive was solo, but I was wearing twin 72s, well and thoroughly pumped up.

While I can't agree with her methods, I find it hard to fault her too. She probably sips air as is often the case with very experienced divers, and presumably she is very comfortable in the water as it is her regular dive location.

As for her profile, my guess is that she does pretty much the same dive each day, and runs the same profile. It's worked in the past, so there's little reason to believe it won't work in the future.

I don't think the OP mentions her age but presumably she must be mid 60s or more. I would hope that she is taking her age in to account as it increases.

As far as her gear goes, it might not be ideal, but I suspect that her 40 as more than enough gas to make her way up. Someone referred to her pony and it's reg as possibly being suspect, but I don't think that there's any evidence in the OP to suggest that. I maintain my stage regs as I do my primaries (They're the same model) and I check my gas in those bottles just as I do my main tanks. Swapping regs in nice warm water really isn't much of a challenge...

Lots of people regularly do 200' dives on air, and some people do dives that are much deeper than that on air. It's kinda dumb, but in the right conditions, I suspect that many divers could function reasonably well (as long as the excrement doesn't hit the oscillator). When I was a young buck working in the tropics, 230, 250 on a single over-pumped 80 was a typical day-off dive for some folks.

I put her down in my "cool and eccentric" column, and I hope that we never read about her in the accident reports here. Somehow, I doubt we will...

 

[FiddlerOnTheRoof]

My last dive to the Andrea Doria my bottom time was only 20 minutes and I was required about 58 minutes of deco time on various gases. I don't see how she is doing it safely unless she has a deco chamber in her house conveniently setup in her livingroom... Not to mention 4 plus tanks needed..

 

[Lorenzoid]

When she got back to the rinse station following her dive, she quizzed my husband & I on the length & depths of our safety stops (which WERE beyond the normal recommended stops), telling us, "you can never be too careful".

She seems proud to be such a cowboy (cowgirl?), but praises others for exercising caution. I'm not sure what I would have made of her. I admire her for having learned to dive back in the stone age (the first woman certified in France?), and I admire her passion for diving and the environment. Beyond that, I'm a little ambivalent. Although she gave reasons for diving to 200 feet (healthy sponges, coral, marine life, etc.) how many minutes could she possibly spend at 200 feet on that 83 cu. ft. tank, even if she was using the "back-up pony bottle" as a stage rather than a back-up/pony? Not enough time to really see any of that. I suspect she just likes diving deep for the satisfaction of living to tell the tale.

On the question of would "this intrepid & fascinating woman be considered a 'normal' advanced diver in certain parts of the world" I have to believe that her style of diving is not completely in tune with modern thinking.

 

[Bennno]

I don't see how she is doing it unless she has a deco chamber in her house conveniently setup in her livingroom...

how many minutes could she possibly spend at 200 feet on that 83 cu. ft. tank, even if she was using the "back-up pony bottle" as a stage rather than a back-up/pony?

She probably just stays at max depth for a couple of minutes (if that) and does a 'normal' multi-level dive. If your average depth is only around 20-25m/60'-75' she's not gonna have much deco. It's bounce diving basically. The pony is probably only for bail out.

 

[CuzzA]

It's interesting to read one account of one deep bounce diver on single tanks stirring so much interest, yet this is pretty common for a lot of Gulf rig divers. They do, however, seem to have a higher incident rate. Not sure if that's solely caused by these deep bounce dives or just the natural hazard of diving around these giant steel rigs, plus add fishing to that, but again not uncommon.

I think it really comes down to someone's mindset. Are they a bunch of cowboys, probably, but it is interesting reading many of their stories. Chasing fish to 200-300', something going wrong, 100' CESA to the surface blowing a deco obligation, knowing they have less than 5 minutes to get another tank on and drop down to 60' for in water recompression before they are immobilized from DCS. And then once back on the boat, they crack a beer, "to thin their blood."

I'm not advocating this kind of diving, just pointing out the matter of fact, quick decision making, bold style of diving that would probably kill most divers is likely what allows "most" of them to survive these types of profiles. But the operative word in my last sentence is, "most", not all.