Deep diving advice that goes against conventional thought?

[John C. Ratliff]

If you look at the physics of breathing, you cannot decrease the partial pressure of oxygen in the blood by skip breathing. This is a function of physics, where the oxygen in the breath will diffuse into the bloodstream, and get attached to red blood cells as a function of the ambient pressure. If a person was using up all the oxygen in the breath by breathing, this would be true (that skip breathing could decrease the partial pressure of oxygen in the blood). But when we breath, we exhale something like 16% oxygen in the breath--that's oxygen that under pressure will diffuse into the blood stream. All you are doing is building up CO2 by skip breathing.

We have known the limits of diving on air since the early 1950s and the deaths of divers such as Maurice Fargues. Jacques Cousteau and Frederick Dumas in their book, The Silent World. To push those limits involves risks that are unacceptable to most; and it is a fallacy that the person is only risking his own life and not that of others by engaging in these extreme deep diving activities. Others will try to recover the body, and sometimes at a risk to their own life they will encounter risks that they did not plan for--please view this Tribute to David Shaw to understand that the risks are not simply those of the diver involved.

When I was in the U.S. Air Force, one of our pilots said, "There are old pilots, and there are bold pilots, but there are no old, bold pilots." I wonder if this applies to divers too?

SeaRat

 

[Wookie]

The most glaring thing I'd point out is that the part about "minimal breaths" to reduce nitrogen loading is really bad advice. Sure you're reducing nitrogen, but at the cost of carbon dioxide buildup ... and in those conditions you're trading off one risk for an even greater one (passing out). DCS is fixable ... drowning generally isn't.

Any idiot can dive to 250 feet. Coming back to the surface without injury is the hard part ...

... Bob (Grateful Diver)

Deep in the dim recesses of my memory I seem to remember an article in Sport Diver, maybe in 1996, written by Bret Gilliam (who I otherwise have a lot of respect for) detailing his 400 foot dive on air somewhere in the Bahamas following a DEMA or something. If the article, Bret told us how we shouldn't try this, but the way he did it was.... and then proceeded to outline many of the items in the OP's post. Minimal breaths to reduce nitrogen ongassing, shooting to the first stop from 4 bills + with no ascent rate limits, etc. When I read the article, I got mad, because I was afraid that some fool would also read it, and take it as a procedure to dive deep on air......

---------- Post added March 11th, 2014 at 12:48 PM ----------

To push those limits involves risks that are unacceptable to most; and it is a fallacy that the person is only risking his own life and not that of others by engaging in these extreme deep diving activities. Others will try to recover the body, and sometimes at a risk to their own life they will encounter risks that they did not plan for--please view this Tribute to David Shaw to understand that the risks are not simply those of the diver involved.

SeaRat

Quite frankly, if you choose to recover a body in what I consider a stupid depth (like with Dave Shaw) that is a separate act of stupidity, independent of the first act. I don't feel that someone else's act of stupidity can be blamed for causing me to lose my mind and perform my own act of stupidity. Stupid isn't noble, it's just stupid.

 

[shoredivr]

Wookie, that article was also printed in a book called Deep Diving.

 

[DCBC]

DCBC: Information about narcosis well appreciated. But do you think if we could take narcosis out of the equation that the rest of what this person is saying is valid? I ask this because I thought the narcosis aspect of the list of risks in what he is describing are actually the least of the risks.

Nothing much of what this person is saying is valid in my opinion. Most of what I read Mike just isn't substantiated:

- "you can come up from 240 feet really fast and once you hit like 110 feet then you slow down"

Although really fast isn't defined this is just bad practice. Ascent rate should be slowed as the depth is reduced. The recommended ascent rate (DCIEM) for military and commercial divers is 60 FPM (between the maximum depth and 30 FSW), 30 FPM (between 30 FSW and 10 FSW) and 10 FPM from 10 FSW and the surface. There are of course many opinions on what is optimal; although "really fast" is never recommended at any depth.

- "in other words if you would descend extremely fast and only take like 2 to 3 breaths to 200 feet or so, one you have a lot of air in your tank, two you can think clearly because you do not have nitrogen in you to get nitrogen narcosis to a degree..."

A rapid compression rate will exacerbate narcosis symptoms and not mitigate them. Nitrogen is always "in you". The partial pressure changes as the pressure is increased (it's a function of time and pressure not volume).

- "air can be toxic at 220' and you can pass out."

If you breathe 100% O2 at sea level you have less PPO2 than breathing air at 220'. Oxygen toxicity however is a function of time and partial pressure. The point is that generally speaking, two or three breaths of air having a PPO2 of less than 2.0 ATA isn't sufficient for a person to pass out, as has been suggested.

- "Myself I can go to 300' and it's actually pretty simple..."

There's nothing about a dive to 300 FSW on air that's simple.

I agree with RonGoodman that this guy must have been narced when he wrote this...

 

[John C. Ratliff]

Quite frankly, if you choose to recover a body in what I consider a stupid depth (like with Dave Shaw) that is a separate act of stupidity, independent of the first act. I don't feel that someone else's act of stupidity can be blamed for causing me to lose my mind and perform my own act of stupidity. Stupid isn't noble, it's just stupid.

Dive Rescue and Recovery Teams regularly go into water to recover bodies, be they divers or little girls. Yes, that was stupidly deep for Dave Shaw to dive. But zero visibility river dives in current have their own hazards.

SeaRat

---------- Post added March 11th, 2014 at 12:05 PM ----------

...If you breathe 100% O2 at sea level you have less PPO2 than breathing air at 220'. Oxygen toxicity however is a function of time and partial pressure. The point is that generally speaking, two or three breaths of air having a PPO2 of less than 2.0 ATA isn't sufficient for a person to pass out, as has been suggested.

- "Myself I can go to 300' and it's actually pretty simple..."

There's nothing about a dive to 300 FSW on air that's simple.

I agree with RonGoodman that this guy must have been narced when he wrote this...

DCBC,

I think from this diagram that with the partial pressure of oxygen, breathing 100% oxygen at the surface is the equivalent of breathing air at just 132 feet, not 220 feet of sea water.
U.S. Navy Diving Manual Figure 1-15 Partial Pressure Photo by yaquinaguy | Photobucket

U.S. Navy Diving Manual, March 1970

If you extend that downward, breathing air at ten atmospheres gives an oxygen partial pressure of 2 atmospheres.
Oxgen partial pressure in air: 2.94 psi (20% of 14.7 psi--this is slightly off in the U.S. Navy Diving Manual, as oxygen is actually almost 21% of air)
2.94 psi x 10 atm = 29.4 psi (10 atmospheres x 33 feet/atmosphere = 330 feet)
29.4 psi partial pressure of oxygen in air / 14.7 psi/atmosphere = 2 atmospheres partial pressure of oxygen in air at 330 feet of sea water.

Oxygen will be toxic to most at 330 feet of sea water.

John

 

[Subcooled]

"your best to be on air at about the 240' and under"

Then tell me why air isn't the standard breathing gas on deep dives on offshore oil fields?


"I can go to 300'and (...) once you get to depth you just start flying just like a jet"

Ok, now I understand.

 

[DCBC]

...breathing 100% oxygen at the surface is the equivalent of breathing air at just 132 feet, not 220 feet of sea water.

You're correct John. I'm not generally advocating the use of a high PPO2, but trying to outline that a diver isn't likely to arrive at 220 FSW (after a quick descent) unconscious, simply because they were breathing air for a short time. In the context given, the statement that "air can be toxic at 220' and you can pass out" is incorrect.

 

[Wookie]

Dive Rescue and Recovery Teams regularly go into water to recover bodies, be they divers or little girls. Yes, that was stupidly deep for Dave Shaw to dive. But zero visibility river dives in current have their own hazards.

SeaRat

John

But Swift Water rescue and Black Water rescue teams are specifically trained to do what they do, as are body recovery teams. No one is trained to go to 300 or 400 feet on air, nor is anyone trained to dive to 1,000 feet using any mixture or equipment.

So, if you are a recreational diver trying to recover the body of a little girl in a swift black river, you are stupid, and if you're going to be stupid, you gotta be tough. If the little girl went in the water after being told repeatedly not to, trained not to, and did it anyway, well, I'm not going in after her, because that's just stupid followed by stupid. If a team trained for such an event chooses to do so, their lives aren't really in danger because they are trained to perform the task, and know when to say that enough is enough.

My point was that a dive rescue team knows how to manage the risks of the body recovery, therefore the little girl didn't put anyone else at risk.

 

[Adventure-Ocean]

Living near the ocean most of my life I've seen some egos challenge the limits of the sea and lose. Guys jetskiing storm waves, wiping out and dying. Others go fishing in too small a boat on a rough day. On one day a group of navy personel went diving on a wreck. They had no experience and penetrated it anyway. Two got home and two did not.

Our egos challenge danger at every level. Since the OP has lost friends doing this he clearly knows it's death defying. That's what he wants. Sharing his stories is his way of making sure we all see him as a living dangerous, on the edge kind of guy. He has my vote. Adventure-Ocean

 

[John C. Ratliff]

Wookie,

The little girl in the article is 2-years old; they are "stupid" by definition, but if in cold water can be revived if they have been in less than an hour. This knowledge can lead a diver such as me to do a dive that otherwise I would not do, and perhaps take risks I would normally not take. I cannot speak for you, however.

Yes, diving in excess of 200 feet on air can be a problem; I have done it only once, and that was on Sonny Cockrell's Warm Mineral Underwater Archaeological Project--to 205 feet. I think I was in excess of 200 feet on one other dive, trying to find a downed helicopter off a small island near Okinawa. We aborted the dive when none of our depth gauges would agree on how deep we were, and no bottom was in sight.

However, I do know that whomever does a crazy dive, and looses his/her life doing so does jeopardize the rescue/recovery divers who will attempt the recovery. Not all hazards can be mitigated, and a good example is the dive Hannes Keller made using the Atlantis chamber to determine why it was loosing pressure. On their second dive to figure out what happened, Dick Anderson and Christopher Wittaker found a swim fin in the hatch, but Christopher Wittaker never returned from the dive. His body was not found, and the depth was about 200 feet.

SeaRat