deep air

[DCBC]

You're using an example of a working dive, not a dive done for recreation. Has no bearing on me.

Actually it was referring to recreational cave exploration, but perhaps you don't do that.

I started trimix diving as a graduate student, hardly wealthy. It's a prioritization issue. I want to have fun, safe dives that I actually remember. I PLAN to be doing lots of complex decision making at depth. That's just part of the fun. Diving stoned doesn't help.

Unless you learned how to dive deep air and you wouldn't dive stoned.

I'd rather *prioritize* doing fun dives, which means choosing gases to help *me* have a good time. If that means I can't dive in some far off places or deep every day, so be it. Locations with no access to helium are probably also the same ones with less readily available hyperbaric medical facilities to treat me if I did make a mistake, which of course is more likely if I'm diving stoned. In such remote locations, I'd rather just keep the diving shallow. In any case, to do deep dives safely, regardless of gas mix, you're going to need to spend some money. Really no way around that.

I know all you have to go by is your personal experience and no one is forcing you to listen to people more experienced. You can think what you wish to think, but that doesn't make it true.

I *love* have you just as arbitrarily come up with 50'. Why not 20'? Yes, we *do* need to decide (for ourselves, our families, and teammates) what level of cognitive impairment is acceptable. No question that just submerging in water is already reducing cognitive functions. The issue is how far are you willing to let those functions deteriorate. And they will with increasing depth. And the consequences of bad decision making ALSO magnify with increasing depth. That CESA you so love from 50' might not be a big deal, but if your poor decisions lead you to do the same from 150' with 30 minutes of deco, you're likely not to have such a positive outcome.

Again you show your ignorance, the 50' depth limit has been proven by various hyperbaric research facilities. Do your homework.

If you are doing a 30 min decompression dive without decompression bottles, you shouldn't be in the water at all. Any emergency ascent would be to the bottles not the surface.

...I'm just disagreeing with your earlier suggestion that we should all go get deep air experience before diving trimix. I *do* think that's stupid. To me it's like suggesting all 16 year-olds first learn to drive drunk so that they could manage getting home from a late night out at the bar. It misses a more obvious solution.

I am not the OP. You obviously have equated deep air to driving drunk; your logic escapes me.

Really, I get it that there are easy dives you can do on air at 150' (and deeper). There's nothing the matter with your approach, for you. But that's not how I dive.

Which is what I acknowledged in a previous post.

 

[DCBC]

DCBC's post in the accidents and incident's forums is a real good example of how things are just peachy, then go downhill in a hurry. Slippery incident pit.

The problem would not have occurred if the two PADI Instructors had the training required before attempting the dive. I wrote this in the lessons learned section, because it taught me something. I am still learning and felt it was an important lesson to pass on.

Why put a foot on the banana peel if you don't have to? Back in the 80s, we didn't know better. Now, we have the ability, and resources to reduce narcosis. There was also a time when there weren't seatbelts. Can you be safe without a seatbelt? Sure. Until you get into a wreck.

Because as it has already been pointed-out, deep air dives happen. I advocating that those that do them first learn how. BTW, if people were better drivers, there would be less of a need for seat belts. I'm advocate proper training not irresponsibility. Hoorah!

 

[DCBC]

Dive gear today is amazingly reliable. As long as it works (which is most of the time), it masks all kinds of training/experience issues.

God help the diver with only 50 dives at 200' on air with no deco gas if he should run into a serious issue. You know, just perhaps.

Yes. God help the diver with only 50 dives at 300' on trimix with no deco gas if he should run into a serious issue.

 

[DCBC]

I'd love to see some of your deep cave and wreck diving videos.

I'd love to show you some video, but when I was diving the South Bight Blue Holes of Andros in the early 70's, underwater video cameras were not available. My dive buddy George Benjamin took a few shots, some of which are highlighted in the book "Deep into Blue Holes: The Story of The Andros Project" by Rob Palmer. For film you may have to resort to Cousteau's National Geographic special entitled "Secrets of the Sunken Caves."

 

[cfenton]

If the discussion is on air, I fail to see how talking about ... adds to the discussion.

I'd love to show you some video, but when I was diving the South Bight Blue Holes of Andros in the early 70's, underwater video cameras were not available. My dive buddy George Benjamin took a few shots, some of which are highlighted in the book "Deep into Blue Holes: The Story of The Andros Project" by Rob Palmer. For film you may have to resort to Cousteau's National Geographic special entitled "Secrets of the Sunken Caves."

Well, that settles it then. Deep air is clearly the way to go!

 

[DCBC]

Well, that settles it then. Deep air is clearly the way to go!

I have never taken the position that deep air is for everyone. I do however, take exception to anyone throwing stones at others who dive deep air, based upon their personal decision not to do it, or ignorance of the subject matter. Saying that this practice is foolhardy or irresponsible across the board is unfair to the many divers who have developed their abilities over thousands of hours underwater.

If you don't want to dive deep air, don't. If you do, learn how before you attempt it. For the divers who elect using trimix, that's great; no one is trying to get them to tear-up their trimix tickets. You use what you feel is appropriate for the dive, or like Thal & SurDo2 have mentioned, what's available or assigned.

Deep diving should only be done by experienced divers. What constitutes experience is of course subjective.

 

[TSandM]

All diving requires risk assessments. What mix you dive at a given depth is one of the variables. I have no problem with someone making a rational decision that their desire to do a given dive is worth the risks involved in doing it on a narcotic mix (so long as they are not diving with me . . . ) But I also think that, all too often, decisions in diving aren't rational. I know that, in medical decision-making, I have to remain alert to, and battle my own DESIRE for a given outcome. I may, for example, be tired, and want to resolve a case quickly, and therefore tend not to make a decision that will require a prolonged workup. I have to know that, and make sure I really work to give each possibility proper scrutiny.

Similarly, people who go to Truk WANT to do the deeper dives there. I can see it being fairly easy to hold an internal conversation that convinces yourself that it's okay to do them, since after all, people have dived deep air for as long as there has been diving. But I doubt those decisions are really dispassionate or truly rational.

Personally, I had a couple of extremely unpleasant experiences with narcosis as a newer diver. They caused me to limit my operational range on Nitrox (I rarely dive air). Although I have since been able to go the same places where I had the issues, without the same symptoms, I had an educational experience in Florida in August. There, I had to swim hard on Nitrox at 100 feet, and make navigational decisions and judgment calls. I did not do well. I wasn't offering my regulator to fish, but I was forgetting things and not noticing things around me the way I should (and can, in other settings). Even such minor inattention can cost lives in a cave, as the Calimba accident in Mexico showed us. I do not think that doing those dives over and over again, in an attempt to learn to reduce the effects of the narcotic gas I am breathing, would be a good use of my time. Instead, if I do those dives again, I'll do them on 30/30.

Do I think everybody diving air below 100 fsw is completely nuts? No. But I think making the argument that you should have to do it before you start using a gas that reduces your impairment IS nuts.

 

[DCBC]

Do I think everybody diving air below 100 fsw is completely nuts? No. But I think making the argument that you should have to do it before you start using a gas that reduces your impairment IS nuts.

The OPs opinion was shared by the recreational, military and the commercial diving field not that long ago. The philosophy to "learn the air envelope before moving on to another gas" was to encouraged the diver to gain progressive underwater depth experience before moving into deeper water.

It seems that today, people are taking Advanced Trimix courses certifying them to depths of 330' (after 8 briefing hours and 4 dives (2 to 180') with a minimum accumulated bottom time of 100 minutes. The prerequisites? Being 18 years of age, having 100 total dives, with 25 dives to 100' (50 underwater hours?) Who are we trying to kid here? This is what IS nuts!

 

[wedivebc]

I used to believe deep(er) air was OK and even after switching to RB diving I was not swayed by the argument that RBs involved greater task loading and required a more sober diver. I was swayed by an experience I had with a slow onset CO2 hit. I need to be aware of how my body and mind "feel" when diving RB so that I can react swiftly to any changes in that feeling. If I am impaired by narcosis I may not notice the subtle changes in my breathing, or feeling of well being before it is too late to do anything about it. CO2 is the biggest enemy of the RB diver and since it is known to exacerbate the symptoms of narcosis I need to avoid both as much as possible.

 

[TSandM]

DCBC, we're on the same page when it comes to too much, too soon! I feel the same way about "zero to hero" cave classes. Helium may, indeed, make it seem all too easy to go very deep before someone has the diving experience to make it reasonable to do so. But the helium isn't at fault -- it's the diver's (and his instructor's) decision-making that's the problem. Using narcosis as a way to scare people into taking it slowly seems like a dubious proposition to me.