200ft dive, but avoids the Chamber

[DandyDon]

Wow i've done some stupid things in my life but never for a t-shirt. After a stunt like that i understand why lions eat their young, to weed out the stupid ones.

That is not at all why they do that. Has nothing to do with this issue, but that's totally wrong.

Back to the thread...

OxTox?! What the divers did was stupid, but I don't see OxTox as a real issue. A possibility, but not much.

Have I seen divers do this? Once. I was in a group of 4, the other 3 Instructors - and I still can't believe they didn't warn me of the plan, but as we got deeper on a wall - I stopped at 1.6 PPO (I was the only one on some Nitrox mix) in confusion as the other 3 dipped deeper - then the head Inst disappeared into the abyss, the other two hovering around 150 watching down, me still around 130 or wherever I was at the 1.6 PPO stop. It's been a couple of years, and I just don't recall how long he was gone, but he subsequently came back.

I questioned the actions back on the boat, of course - discreetly, as I was dealing with Insts, and had no idea of what I might not understand. Finally learned that he dipped to 265 ft, felt pretty narced, but had the max depth reading on his computer. I became increasingly mad, but kept it quiet to the group they were leading as we'd all flown down from Texas together, and it was the last day of group diving. I went out with a local Tech Inst the next day, no one else in the group dived again before going home. He had the hit-by-Mac-truck symptoms, I later learned, but never sought treatment, never had worse problems, seemed fine on the flights home 2 days later when I saw them again.

Yeah, it was "dumb" by a lot of standards, but it happens. I still dive and train with him but question him extensively on any dive plans. He teaches rather conservatively, by the way.

Back to the dumbbutt divers described in the DAN story - which was aimed at showing that DAN is there for divers even when they feel stupid and embarrassed, yeah - it was dumb, but divers do these things at times. The point of the DAN release is that even if you feel really dumb and embarrassed, still - call DAN for professional treatment without ridicule.

OxTox?! Where did that come from?

 

[Cacia]

you'll see that this is published on DAN's website. I think we can believe at least DAN's part of the story.

this is the part that is disconcerting to me...I might contact the named physician and just query this a bit, being the curious person I am.

I don't care to flog this guy, just understand why the "treatment" seemed to consist of emotional support and not too much more...just does not seem like any medical decision I have ever witnessed. BUT...I have said maybe there is missing information.

Enquiring minds want to know. Should not be too hard just to ask...right?

 

[sandjeep]

You know, I would gladly trade all of my 'been there, done that' T-shirts for the time they cost me away from my wife. I will not bash this diver, just hope he wakes up before we read his obit someday.

 

[lamont]

Effects of Oxygen at Depth -- The effects of oxygen are increased at depth so that the maximum PO2 in diving is 1.6 ATA, and this is achieved at 218 fsw breathing air, 132 fsw breathing 32% O2, and 20 fsw breathing 100% O2.

You don't tox immediately if you exceed 1.6 and its possible that high ppN2s protect somewhat against the ppO2s -- lots of air divers have been to 250+ without toxing or displaying symptoms (particularly before anyone knew any better) -- _Caverns Measureless to Man_ has a bunch of depth record attempts on air where 1.6 ppO2s were exceeded...

Not that its a particularly good idea, but ~200 on air is possible without a tox...

 

[super opus]

i ran the numbers lets say 7 mins at 220 it could be done on a 100 with with very good air consomston (take a look)but he did go over his po2 mod for air is 217 im sure it was just 21% all i can say was per luck thats how ppl die his lucky he gets to go home to his wife and his budy too i wouldnt even now w hat to say about that
Dec to 200ft (4) Air 50ft/min descent.
Dec to 220ft (4) Air 60ft/min descent.
Level 220ft 2:40 (7) Air 1.61 ppO2, 220ft ead
Asc to 40ft (13) Air -30ft/min ascent.
Stop at 40ft 2:00 (15) Air 0.46 ppO2, 40ft ead
Stop at 30ft 2:00 (17) Air 0.40 ppO2, 30ft ead
Stop at 20ft 3:00 (20) Air 0.34 ppO2, 20ft ead
Stop at 10ft 4:00 (24) Air 0.27 ppO2, 10ft ead
Surface (24) Air -30ft/min ascent.
lets say his budy went to 275 cave good vis and was down for um 10mins cuz his super man some thing is not adding up or i might be giving them to much time
Dec to 200ft (4) Air 50ft/min descent.
Dec to 275ft (5) Air 60ft/min descent.
Level 275ft 4:45 (10) Air 1.96 ppO2, 275ft ead
Asc to 100ft (15) Air -30ft/min ascent.
Stop at 100ft 1:10 (17) Air 0.85 ppO2, 100ft ead
Stop at 90ft 2:00 (19) Air 0.78 ppO2, 90ft ead
Stop at 80ft 1:00 (20) Air 0.72 ppO2, 80ft ead
Stop at 70ft 2:00 (22) Air 0.65 ppO2, 70ft ead
Stop at 60ft 2:00 (24) Air 0.59 ppO2, 60ft ead
Stop at 50ft 3:00 (27) Air 0.53 ppO2, 50ft ead
Stop at 40ft 4:00 (31) Air 0.46 ppO2, 40ft ead
Stop at 30ft 5:00 (36) Air 0.40 ppO2, 30ft ead
Stop at 20ft 8:00 (44) Air 0.34 ppO2, 20ft ead
Stop at 10ft 13:00 (57) Air 0.27 ppO2, 10ft ead
Surface (57) Air -30ft/min ascent.

 

[do it easy]

Yeah, but the diver said he had 300 psi at 50', so I don't think he could have done the shallow stops- I guess he was doing deep stops instead

This is an interesting dive since it runs right into the personal choice debate. Yes, the dive he did was certainly not up to best practices, but it's his life to gamble. For him, the reward of the t-shirt was greater than the risk of the dive. I think that most of us will agree that this is too steep a risk, but maybe for a t-shirt and a beer...

At what point does the dive become safe? With a 19cf pony? How about a 40cf pony? Everyone will have a different line in the sand, depending on their experience, training, and paranoia level. I find the psychology of it fascinating- either people think that diving is completely safe, or they knowingly take risks.

 

[Laughing Swordfish]

I smell a BS story. First, it's amazing that this diver (and especially Mr. Bulletproof) didn't suffer O2 toxicity (see below). Second, it's highly unlikely that calling DAN with this story would result in a "don't worry about it" result.

Effects of Oxygen at Depth -- The effects of oxygen are increased at depth so that the maximum PO2 in diving is 1.6 ATA, and this is achieved at 218 fsw breathing air, 132 fsw breathing 32% O2, and 20 fsw breathing 100% O2.

This is due to the effects of Dalton's Law which states that on descent, the partial pressure of all component gases increase in the same ratio as the total pressure. This results in the creation of the elevated pO2 that causes the convulsions of O2 toxicity and is the direct cause of nitrogen narcosis and along with Boyle's law, is the cause of decompression sickness.

The Paul Bert Effect

Muscle twitching and spasm
nausea and vomiting
dizziness
vision (tunnel vision) and hearing difficulties (tinnitus)
twitching of facial muscles
irritability, confusion and a sense of impending doom
trouble breathing, anxiety
unusual fatigue
incoordination
convulsion

Convulsion at depth in water usually results in drowning or arterial gas embolism.

I've done 30 minutes on pure o2 at 60 feet in a chamber and didn't tox (ppO2 around 2.8 I think). In fact I didn't experience any of the well known symptoms of a CNS hit. Neither did anyone else I know who has done it. 1.6 is a very conservative upper bound for ox tox.

Read 'Shadow Divers' if you haven't done so already. It will give you a good idea of the kinds of air dives people used to do before mix became common. 200-250 feet was done a lot by the more adventurous ones out there. At that depth I think CO2 blackout is by far the bigger danger. Risks of ox tox are often way overstated IMO.

 

[lamont]

Yeah, but the diver said he had 300 psi at 50', so I don't think he could have done the shallow stops- I guess he was doing deep stops instead

This is an interesting dive since it runs right into the personal choice debate. Yes, the dive he did was certainly not up to best practices, but it's his life to gamble. For him, the reward of the t-shirt was greater than the risk of the dive. I think that most of us will agree that this is too steep a risk, but maybe for a t-shirt and a beer...

At what point does the dive become safe? With a 19cf pony? How about a 40cf pony? Everyone will have a different line in the sand, depending on their experience, training, and paranoia level. I find the psychology of it fascinating- either people think that diving is completely safe, or they knowingly take risks.

I just think that bounce diving is stupid. If you're not going to spend 20-30 mins there the depth is meaningless, it doesn't say anything about the skill level required to be at that depth and be comfortable and be able to get back consistently every single time...

I probably could take my double-130s fill them with 10/70 and do a bounce dive to 300+ and get back alive at least once... but, I don't have the skill though to really dive at that depth... (yet?...)

 

[gcbryan]

I just think that bounce diving is stupid. If you're not going to spend 20-30 mins there the depth is meaningless, it doesn't say anything about the skill level required to be at that depth and be comfortable and be able to get back consistently every single time...

Why is it stupid to spend less than 20 minutes at max depth? You could go down a wall and spend only a few minutes at max depth and view the rest of the wall on the way up, spend a lot of time in the shallows and have a great dive.

It seems stupid to me to stay 20-30 minutes at max depth if you are on a wall.

 

[nlbford]

I'm just wondering if he is gonna wear the T-Shirt to his open casket funeral . . . which sounds like it will probably happen real soon.