Exactly how deep is "Deep Air?"

[The Chairman]

It's not what you know NetDoc, it's what you think you know.

Just an ad hominem... no substance but vague inferences. While I have grown to expect that from you, I still find it tiresome.

So how do I demonstrate my arrogance? Diving deep on air? Lamenting the passing of macho in diving? Perhaps my biggest sin is that I disagree with you and I am not afraid to say so. Perhaps you can post a study showing us that deep air is inherently safe? Perhaps one that shows that only sissies get narced and that real men don't need helium.

 

[UCFKnightDiver]

Thats certainly not true. There is an improvement in performance with repeated exposure (although you are still affected to some degree). The only thing that consistantly dropped for me during repeated testing in the chamber was my reaction time. This was consistently lower than non-narcosis testing.

Narcosis is in some ways similar to intoxication, but it is NOT the same thing. There may not be "better methods" for the job available. You choose what risks are, or are not acceptable to you. You are the only one that can make this choice for you, but you can't make it for another diver.

As to the improvement in preformance with repeated exposure, the study I read said that this is the case if you're diving deep every day, (other multiple studies I have read say that you can't improve preformance in critical thinking in regards to narcosis.) which most diver's arnt so a moot point, and a false one for most. As soon as you take a break of a day or more from doing so you're back to square one.

I'm not making choices for other divers, I'm simply stating safe practices on a public forum where on the other hand you are not. There's a difference between advocating something silly and doing it yourself.

Also I'm with LiteHedded, Mystery Sink was closed due to deep air, Eagles Nest I believe for awhile was too.

 

[The Chairman]

I'm not saying you don't know of where you speak and if I gave you that impression I apologize.

Not a problem. Not everyone likes technology, and to be certain: I didn't take your post as a slam against those of us who are early adopters. I just wanted to make sure you understood a bit of my background.

In actuality, I gave up diving for a long while because of Mystery Sink. I was probably one of the last divers in there and it scared the crap out of me. I went OOA while I was fairly deep and found my J-valve had already been tripped. Holy Schnieke! I was no where near the depth of the guys who had died, but the kick back to the surface seemed to take forever. Our motive? We wanted to see the hole where these guys died. It took me many years to get back into diving, and I don't take chances like that anymore. This time around I use a [-]depth gauge[/-] PDC, an SPG, an octo and even a BCD. We thought those were for sissies back in the seventies. You won't catch me without them now. No, I don't miss the macho in diving at all.

Somehow, according to DCBC, my cautious approach to diving makes me arrogant. Let him think what he will. I am way comfortable with the way I dive and don't feel a need to chase after "macho" anymore and I am certainly not a hard head diver.

Attitudes change with the times. Like the voodoo gas before it, Trimix has become more main stream mitigated by a definite desire to not waste money in this tight economy. So we have a thread on what we all consider deep air. For me, that's where the END>100fsw. Do I go deeper than that? Sure. I am not yet Trimix certified and it's my very next class. It has nothing to do with achieving deep dives quicker (as one suggested). Rather, it comes from a rather cautious and research driven approach to diving. I find it good to humble myself and to continue my diving education whenever possible. I have learned a lot right here on ScubaBoard, and I am grateful for all the posters who have shared their insights.

 

[LiteHedded]

amen Pete!

 

[*dave*]

So we have a thread on what we all consider deep air. For me, that's where the END>100fsw. Do I go deeper than that? Sure. I am not yet Trimix certified and it's my very next class. I

Pete, you've lost me. I believe you have either stated or inferred the following:

Deep air = END>100fsw
Deep air is bad
Deep air is unsafe
Pete is a safe diver
Pete does not dive He
Pete does dive deeper than an END of 100fsw
Pete dives deep air

What did I misunderstand?

 

[Cave Diver]

Let's try to keep this semi-ontrack


The "Deep Air is Bad" thread is over that way ==========>>

I can't answer. I really can't answer.

I'm taking this poll to be a reflection of at what depth do you become impaired as a result of narcosis and if I'm correct, then it's impossible for me to say.

In April 2008, I air dived to 213 ft to look for an galleon's anchor in warm, clear waters in the Philippines. I did it safely enough, and was able to draw an accurate map for the (trimix) divers who followed me.

In June 2008, I was lucky enough to dive South Africa for the Sardine Run (60 degree Fahrenheit waters, lower vis) and I was definitely feeling the effects at 100ft.

Last year I did my Commercial Diving ADAS ticket in Tasmania in winter. At 170ft in temperatures of around 43 degrees Fahrenheit, I carried out fairly complex manual tasks, whilst reporting my progress to the surface.

Great post! Any idea why you may have felt it more at 100' in June than you did on your commercial dive?

Lower viz? Higher work of breathing? Fewer "build up" dives to raise your tolerance?

 

[The Chairman]

Pete, you've lost me. I believe you have either stated or inferred the following:

Deep air = END>100fsw
Deep air is bad
Deep air is unsafe
Pete is a safe diver
Pete does not dive He
Pete does dive deeper than an END of 100fsw
Pete dives deep air

What did I misunderstand?

The logical conclusion of me taking a trimix course.

Again, this thread is all about what you consider to be "deep air". The agencies classify any dive below 60fsw as deep. While I concur that the onset of impairment starts there, I don't find that it really seems to mitigate creative thought or deductive reasoning dramatically until END>100 fsw. Depending on the complexity of the dive in question, I might very well descend LOWER than 100 fsw, but not without a lot of fore thought and planning. I certainly don't recommend these depths to new divers nor do I equate trimix, heliox or other mixes with people trying to short cut their learning curve due to some societal perversion against machismo. It does show a respect towards diving deep that I find missing in many comments.

Now Dave, what depth do you consider "deep air"?

 

[DCBC]

I think the cave divers tend to be the ones more sensitive to the deep air stuff because of losing access to sites. in principle I agree with you DCBC. dive deep air if you want. I don't care. but things change when it starts affecting other people. things like the deaths at mystery sink in orlando. divers get themselves dead, then some of the recovery team gets themselves dead. ...and the site gets closed.

The point you make is a fair one. It may be even more appropriate if you said "Deep air in a Florida cave may affect people other than the person diving deep air."

I haven't researched the statistics, so I can't say with certainty, but I'd guess that the greatest majority of the world's divers who dive "deep air," do not dive in Florida caves. It's likely that the majority don't dive in caves at all, but I understand your position.

 

[Trace Malinowski]

Many recreational divers with insufficient training in gas management, deep diving, and narcosis management dive every day to depths of 130 feet on many walls and wrecks ill-prepared for the worst case scenario of an OOG situation at max depth. We can claim they are doing this "safely" because the death toll isn't exactly disproportionate to diver deaths in shallower waters or even at the surface.

Since they can handle it, technical divers with greater training, experience, and who are well-rehearsed in gas sharing and emergency procedures aren't exactly setting themselves up to meet the Kracken by using air to 130 feet.

Even in the cave community in which there is no easy way home from an emergency situation at max penetration, the rule of accident analysis is not to dive deeper than 130 feet on air. True, many believe that this should be scaled back to 100 feet, while others would want to remove air for depths as shallow as 60 to 80 feet.

I think 130 feet is a fine arbitrary maximum. We can consider 130 feet "aggressive," 100 feet "average," and 80 feet "conservative" when it comes to air diving in overheads. The same may be applied to recreational divers due to single tanks, training, and relatively unpracticed emergency procedures.

Once we leave the "safe" limits of air diving, we find ourselves in a gray area from 130 to 150 feet. Due to the wide availability of "Enriched Air" Nitrox and the fact that nearly every avid diver has nitrox training, you can probably get away with safe "advanced nitrox" level dives in open water. I know TDI decompression procedures is rated to 150 feet, but advanced nitrox is rated to 130 feet. Many divers believe that the combined course has trained them to use both nitrox and deco procedures to 150, but in actuality that's not true. However, most divers with these ratings will employ up to Nitrox 26 to 150 giving an EAD of 138 feet and a ppO2 of 1.41. Most cave divers would dismiss this as being too aggressive an approach since Trimix is available everywhere in North Florida. In places where Trimix is not available and where dive plans are relatively simple, such as deep walls or exterior wreck exploration, advanced nitrox diving is pushing the envelope of what we know about safe parameters.

With this in mind, I define "Deep Air" as being beyond the limitations of recreational diving, beyond overhead protocols, and beyond deeper enriched air diving. The "Extended Range" zone beyond 150 feet is where I would place the general term "Deep Air."

I respect the right of each individual to define this term differently especially for their own personal limitations.

 

[DCBC]

As to the improvement in preformance with repeated exposure, the study I read said that this is the case if you're diving deep every day, (other multiple studies I have read say that you can't improve preformance in critical thinking in regards to narcosis.) which most diver's arnt so a moot point, and a false one for most. As soon as you take a break of a day or more from doing so you're back to square one.

That is not my experience. There are thousands of divers diving deep air safely as I type this. Divers have been doing this for decades.

I'm not making choices for other divers, I'm simply stating safe practices on a public forum where on the other hand you are not. There's a difference between advocating something silly and doing it yourself.

The only thing I've advocated when discussing deep air is that:

a) The diver should have the requisite training and experience; and
b) The diver has to use his/her best judgement and dive within their personal safety envelope.

If a person is properly trained to dive deep air, the activity can be conducted safely. The same can be said about cave diving, wreck diving, etc.