Certified at altitude in South Africa

[Rick Inman]

A lot of talk here, but not much science, and I, for one, would like to learn something.

At an altitude of 18,000 feet, the pressure is about one-half as that at the surface. That seems to me to be the same change in pressure as ascending form 15.33' deep to the surface. So, climbing in altitude from 0' to 5000', is less than a third of that, or, roughly, the same as 4' under water to the surface.

I can't be doing the math right here. Can someone actually give us some date on this?

 

[Kim]

I agree - there hasn't been much certain knowledge yet. I do wonder though if the effects of less than 1ATA are directly comparable to the effects of more. Altitude sickness affects people very severely at height - already 12-15,000 ft can do that. As you say according to the pressure difference that should only be the same as a small depth of water. The effects are radically different though.
Deep space is only a difference in pressure of 33ft in water (1ATA to nothing) - but again - pretty serious stuff!!

I too am interested in the facts on this.

 

[DandyDon]

Thanks Andy and GDI for constructive posts. I do hope we haven't run Tromp off with all this commotion...

My first post here did indeed include a casual reference to DAN's general guidelines. After I got up (resting an injured leg this week) and checked the NOAA manual, I did find that ascents to 5,000 feet after 50 foot dives can be done after a suggested surface interval of 12 hours or less, depending on the actual dives and periodic surface intervals.

Again, I know nothing about the road he will take home, how soon he will ascend to significant altitudes, and was leaving it to him to make of my suggestions as he would based on those facts available to him. I'm sure that Tromp will be diving conservatively with his wife and 10 yo daughter, I'm also sure that he would like conservative suggestions - especially with regard to his child.

I am not a safety oriented person by nature, but I do try, and in the spirit encouraged on this board, always try to offer safe suggestions. As has been stated elsewhere on the Dr.Deco forum, little is known about the affects of diving on adolescents, so I further thought that more conservative suggestions were in order. I might be one of the first to head up the hill alone, but one of the last with my grandson if he'd been diving with me.

Again Tromp - enjoy your trip and tell us about it when you get home.

 

[JeffG]

DandyDon is coming from a recreational diver's perspective, and since those of us who can't calculate our own ascent profiles have to rely on something, DAN's guidelines are as good as it gets

and that is fine. If you don't know, don't do it. But if you look at it realistically its not that scary.

JeffG is coming from an experienced, tech diver perspective.

I wouldn't go that far

he knows how to do his own ascent profile and doesn't have to wait around for what, with his knowledge, is a waste of time (but Jeff, since i can't dupliacate your calculations due to lack of knowledge, i won't take this trust-me dive uphill with you )

But look at altitude diving from a deco perspective its not a big deal...if...if...you came out of the water clean. But even then...it takes time to get your gear off, chat and lie about your dive to your buddies, and then actually drive and "do the ascent".

GDI is coming from the instructor's perspective, and is concerned that those
who don't know what they are doing may get hurt. he's basically saying
that while some people can calculate their own ascent profiles, this is not
something to be embarked upon lightly by those, like me, without sufficient
understanding of the issues involved. thus, since there's so much
uncertainty for those of us who don't "know it cold," it makes sense to wait

I understand that and that too is ok, but I would rather try to get divers to think. Thats why I asked questions, so that they could question the conventional BS surrounding altitude diving.

i'm a lawyer, so i'm certain by now i've pissed all three parties off... but
so what? i do it on a daily basis eyebrow

my legal bill, btw, should arrive shortly

Doesn't piss me off. I thought it was a good summary, but I'm not going to pay for it.

 

[Kim]

Thats why I asked questions, so that they could question the conventional BS surrounding altitude diving.

This makes me curious. Just to be clear, I didn't think that this was about altitude diving - it's about diving at sea-level and then returning to altitude.
That aside - what exactly is 'the conventional BS surrounding altitude diving' ? I'm genuinely curious.

 

[DandyDon]

This makes me curious. Just to be clear, I didn't think that this was about altitude diving - it's about diving at sea-level and then returning to altitude.

That was my understanding.

That aside - what exactly is 'the conventional BS surrounding altitude diving' ? I'm genuinely curious.

Me, too. If the member knows more than NOAA, I'd like to see the supported facts.

 

[JeffG]

This makes me curious. Just to be clear, I didn't think that this was about altitude diving - it's about diving at sea-level and then returning to altitude.

Yes you are right, misnamed by me.

That aside - what exactly is 'the conventional BS surrounding altitude diving' ? I'm genuinely curious.

See GDI's post (about 6 or so back)

 

[Tromp]

Hi, thanks will stay in contact. Stay in Fairlands and dive with Calypso in Byers Naude drive.

 

[JeffG]

Me, too. If the member knows more than NOAA, I'd like to see the supported facts.

I'm going to go back to BoomX's post.

forget it.



Please everyone...stay at sea level for a full 24hrs before going up a mountain. You will die a gross and horrible death.

 

[Kim]

See GDI's post (about 6 or so back)

But I thought that that was DAN & NOAA's official position for recreational divers (maybe any divers as they mention deco as well). Is this simply wrong? I certainly didn't realize that the same deco principles would apply to less than 1ATA. What am I missing here? (Please don't tell me to go take a course! )