high altitude diving

[DocVikingo]

The full test protocoll was published in UHMS 39 - Flying after Diving, which is available at Rubicon.

Any chance you could be so kind as to post that URL?

Thanks,

DocVikingo

 

[Mod63]

Flying after Diving
aslo recommended: The Physiological Basis of Decompression

 

[DocVikingo]

Flying after Diving also recommended: The Physiological Basis of Decompression

Sorry for being so dense today, Mod63, but I'm having a hard time here.

The first URL you posted is about various and sundry aspects of flying after diving, that is ascent to altitude after SCUBA. There's really no discussion about diving at altitude, a very different matter, and the aspect of your posts with which I am taking issue.

The only section of that workshop written by Bühlmann is "Flying After Diving: Concept, Experiments in Switzerland" and not surprisingly its focus is not diving at altitude. Moreover, I cannot find Bühlmanns' Lake Titicaca tables (in fact, I can't even find reference to Lake Titicaca) nor any set of tables for diving in the range of 8200ft to 14800ft anywhere in that entire workshop.

At this juncture I would mention that I'm not sure he ever even went to Lake Titicaca, to develop and field test dive tables or for any other reason. I'm under the impression that the data from that lake he used in testing his algorhythms was obtained by a British military officer, a Capt Moody.

As for the second link, there is a piece by Bühlmann entitled “Diving at altitude and flying after diving.” Again, apparently no tables specifically developed and field tested at Lake Titicaca, although at least the lake is mentioned in the piece where it is indicated that the PN2 t.-values for dives at reduced ambient pressures in certain Figures were in part derived from dives there. I could not locate any set of tables for diving in the range of 8200ft to 14800ft, although there is mention of tables used in Switzerland covering 0-700m/0-2297ft and 701-2500m/2300-8200ft. Of course, the original poster asked, “Does anyone know of decompression data for use above 10,000 feet elevation?”

I'd be grateful for any clarification you may be able to offer.

Thanks,

DocVikingo

 

[Mr Carcharodon]

It's a good question if Buhlmann's limits apply at altitude. In one of Baker's paper he said they do to about half an atmosphere. But beyond that allusion I do not know where that came from. 10,000 feet is a reduction in pressure of 31% with respect to sea level. So if you accept the 50% criterion Buhlmann would apply. Of course I guess you would have to stay at altitude for a couple days to get equilibrated for that altitude and then knock 10 feet of the tables to make it work out, or book keep the pressures from the lower altitudes.

 

[limeyx]

...and controversial. Believe it or not, some people argue there is no need to factor altitude into dive planning at all.

Nutjobs

 

[amascuba]

Nutjobs

Takes one...

 

[Mod63]

DocVikingo,

page 215ff (223ff in the PDF numbering) presents the Bühlmann data, including the Lake Titicaca dives. These were done by British Marines under Capt. Moody, based on Bühlmanns research. This paper is the easiest to obtain when looking for the data Bühlmann collected, both from chamber and "real" dives.
I added the second paper as a general reference and good reading on decompression theorie.
Lastly, Bühlmanns high altitude tables where published in "Tauchmedizin", his main work, which unfortunately is only available in German. The appendix has the full set of tables (Zürich 1986).

Reading through "Tauchmedizin", I came accross the following information, which I will paraphrase:

- 1969, Swiss Army divers did training at 1800m with French GERS tables. All dives resulted in immediate and severe DCI -> this was the trigger for Bühlmann and resulted in a frist set of tables in 1972
- In 1986, the ZH-86 tables were developed and based on an initiative of Capt. Moody, a joint British-Swiss Expedition ("Paddington Diamond") went to Bolivia
- in 1988, members of the team of '86 went to Mout Kenya and did 18 dives at altitudes between 4400m-4780m with out incident

So as stated: There are tables for high altitude diving, they have been published (together with the underlying data) and they are not theoretical but "dived".

Jürgen

 

[TheAvatar]

I've dove on the 10K table. Our team has used the 12K table on occasion, but those dives were shallow. We use the NOAA tables for predive ascent/depth adjustment/and post dive ascent.

 

[Crush]

Two quick thoughts:

• Ultra high altitude lakes tend to be shallow. If that is true in your case then it may even be shallow enough to dive on pure oxygen, or at least a highly enriched nitrox mix. That would significantly mitigate your risks.
• Thalassamania was involved in the world record highest ever altitude dive by Dr Charles Brush in Lago Licancabur (at around 17,000 feet). I am sure if you PM'ed him he would share his insights.

If I am not mistaken, Thalassamania may have helped with the training...

 

[Bubble Dragon]

A slightly different but related matter:

I'm visiting friends in Bali & staying at their house in the mountains.
My friends are also keen on going diving with me, but they haven't done it since they moved to Bali last year.
Now my question: is there any serious risk of getting bent after 2 dives to let's say 30m & then going back "home" afterwards which happens to be at an elevation of 500m?

Thnx for your input!