dive computers vs dive tables vs WKPP practices

[KLD]

DennyB,

Good observation.

Maybe check out the NAUI Rec and Tec Tables -- as published, tested, released and used in the field for TRAINING of divers (first, and foremost). The Rec Tables for air, EAN32, and EAN36 are trivial to use, and have simple "backup" rules, and range sea level to 10,000 ft elevation. The Tec (deco) Tables are for trimix, nitrox, helitrox, etc. with switch to pure O2 at 20 fsw. Other Agency folks are reported to also be users.

Tables, based on RGBM, are correlated with data
from RGBM Data Bank using standard probabilistic deco
risk analysis (described TDID, RGBM In Depth, etc). Don't
know exact count, maybe a bunch of 10,000s of dives by
now without mishap just on these Tables.

BW

Now that it seems everyone who's contributing to this thread has entered their two cents worth (and much of it was worth far more than that in my opinion!) I have one last question on the subject:

We all seem to agree, to one degree or another, that the NAVY tables are wrong. The PADI Tables are pretty wrong, and that would go for most every deco plastic card table out their in someones dive box printed before say, oh 1990 or thereabouts.
What would it take to get the industry in general to re-write the dive cards and 'wheels' to reflect the deco profiles that are produced with say...V-Planner or GAP software, etc.?

Take any PADI or other deco card and run a software program like those discussed in this thread and you'll see the complete difference in the profiles. Since most divers entering into the sport are interested in obtaining the latest regulator, the fastest scooter, the best tank, the cutiest mask, etc. it would also seem to me they'd want to be taught with the latest technologically advanced deco profiles, Hummmm?

Any comments from our illustrious leaders in the area of physics and decompression science about how we can demand the instructors and oganizations step up and adopt the latest and most accurate for our up and coming new divers?

thanks in advance...
db

 

[Dr Deco]

Hello cdennyb:

I am not so sure that I would go so far as to say that the earlier tables (US Navy, etc) are wrong. They produce useful dive schedules within the recreational range and have demonstrated their utility over the decades. Whether the theory upon which they are based is correct is a different story all together, but the tables were developed empirically and give “Nature’s answer” to the question.

When one goes very deep, there are certainly problems with the tables but, to some extent, this is based on how the decompression is performed, I believe.

Contemporary decompression concepts are composites of several ideas that have come into conjunction in the past decade. We have the single bubble model of Michael Gernhardt, the stress-assisted nucleation concepts of E. N. Harvey, the nuclei reduction studies (0-gravity) of Mike Powell (Dr Deco) at NASA, and the mathematical models of RGBM that incorporates actual dive data to produce a table.

All of these point to the fact that micronuclei concentrations are of importance. Dive tables are only then one half of the equation. The reduction in nuclei generation is the other half. That is the part not being taught by dive agencies. Yes, we have always heard that exercise will promote the bends. But so will about a half dozen other things on the list. Nothing but gas loads and exercise will cause so much trouble. [Here I am omitting some “constitutive factor” that is probably genetic and remains to be found.] :280:

Coupling

It is interesting to see the coupling of exercise and decompression in the laboratory to get a good idea of what all of this can do. None of it is a part of a table of a meter at the current time, but all of it is important and is employed in the NASA EVA work.

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology :1book:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[fins wake]

We all seem to agree, to one degree or another, that the NAVY tables are wrong. The PADI Tables are pretty wrong, and that would go for most every deco plastic card table out their in someones dive box printed before say, oh 1990 or thereabouts.

No, we don't agree. The fact that DCI incidence went from enormous in the late 19th Century (caisson workers, early military & commercial divers) to what BRW himself regards as "statistically insignificant" is proof of that. Which brings me to:

It's taken a century for things to retrack. Haldane was a truly great physiologist, but not a good modeler.

This is a surprising statement from two points of view:

(1) Haldane's model actually functioned. Paul Bert's model, although very interesting did not dramatically reduce caisson disease in tunnel workers or DCI in military or commercial divers. Haldane's did. And with modifications from Workman and others, neohaldanian models still function for the vast majority of divers out there. A model which has worked for almost a century? Not a good modeler? Hogwash!

(2) It is very unusual to see a researcher pour scorn on a fellow researcher predating him by a century. Did Einstein pour scorn on Newton? (No, and in fact einsteinian physics have not entirely replaced newtonian physics, especially in everyday application. The Newton parable is BTW used by a lot of quasiscientific divers who clearly do not understand the theory and concept of how scientific theories evolve. A class in Popper and Kühn is vividly recommended!)

Not that I'm comparing Dr Wienke to Einstein, but the principle remains the same in any case.

Perhaps I'm misunderstanding something, Bruce, but your posts does look like a shameless plug for the software you own and market. And not a very subtle one at that. Perhaps it's just a cultural or ethnic thing, as nobody else here seems to react, but it doesn't look good to me.

That said, I agree the WKPP accomplishments are remarkable.

Personally I think serious scientific study under controlled conditions by independent third parties would be required to see which bits fall under true decompression advances (doubtlessly some would) and which bits can be explained otherwise, e.g. by weeding out the "average Joes" who are prone to DCI at an early stage leaving only non-statistically representative "survivors", or by superior fitness (and hence vascularization) or by e.g. Dr Powell's interesting data n post-dive exercise and DCI (which I think is highly interesting).

This means controls, this means people of differing physical shapes etc. All this is rather detrimental to the efficient mission-oriented nature of the WKKP's work, and it's their show, so I understand if they don't feel obliged to redo their challenging dives under such circumstances.

But until then, it really is very strange to pull out semisaturation dives in caves and project the results in other areas.

I do understand Rob's initial response, as the black-and-white cheerleader-type threads do grate after a while.

And finally, I do subscribe to the bubble model theories myself, and therefore dive VPM-B whenever possible. Which, BTW, I have no commercial interest or stake in.

 

[KLD]

Fins,

Busy day.

Haldane was a great physiologist, but really missed the
computational boat on bubbles. Also Haldane found deep
stops were necessary for deco but had no way to put them in
his dissolved gas (only) regimen. Chemists (like Hill and
others) couldn't persuade him to do so either. Einstein never
accepted quantum mechanics as such, yet most of modern
physics is based on quantum mechanics (take it from me as
a particle physicist by training). Newton once called
Tycho Brahe (observational astromer) a twit, yet
with Kepler, used Brahe's data on planetary motion
to validate the universal law of gravitation (plus calculus
to some extent in the process).

DCS stats for no-deco (rec) diving are certainly in the
noise, but stats for deco diving ala Haldane are not.
The USN is also embarking on an ambitious (further) testing
schedule of deep stops which are intrinsic to dual phase
staging (bubbles plus dissolved gas). This goes along
with other data we have collected.

My plugging for using dual phase models comes from
concern for doing modern deco diving safely and efficiently.
Outside of a protective licensing fee, I get NOTHING from
all the RGBM meters, software, and tables out there.
Check with Suunto, Mares, Dacor, NAUI, Steam Machines,
Plexus, Zeagle, HydroSpace, GAP, ABYSS. However,
I do choose carefully who I license RGBM to for redistribution
and use. Call it "technology protection' if you want,
considering the publications, testing, data, correlation, etc
done over the past 12 -14 yrs, in many places.
Sorry if you think otherwise, but I generally avoid these
Lists for a bunch of reasons, but frequently get called out
to "explain" something. More than happy to skip same.


Cheers,

BW

No, we don't agree. The fact that DCI incidence went from enormous in the late 19th Century (caisson workers, early military & commercial divers) to what BRW himself regards as "statistically insignificant" is proof of that. Which brings me to:

This is a surprising statement from two points of view:

(1) Haldane's model actually functioned. Paul Bert's model, although very interesting did not dramatically reduce caisson disease in tunnel workers or DCI in military or commercial divers. Haldane's did. And with modifications from Workman and others, neohaldanian models still function for the vast majority of divers out there. A model which has worked for almost a century? Not a good modeler? Hogwash!

(2) It is very unusual to see a researcher pour scorn on a fellow researcher predating him by a century. Did Einstein pour scorn on Newton? (No, and in fact einsteinian physics have not entirely replaced newtonian physics, especially in everyday application. The Newton parable is BTW used by a lot of quasiscientific divers who clearly do not understand the theory and concept of how scientific theories evolve. A class in Popper and Kühn is vividly recommended!)

Not that I'm comparing Dr Wienke to Einstein, but the principle remains the same in any case.

Perhaps I'm misunderstanding something, Bruce, but your posts does look like a shameless plug for the software you own and market. And not a very subtle one at that. Perhaps it's just a cultural or ethnic thing, as nobody else here seems to react, but it doesn't look good to me.

That said, I agree the WKPP accomplishments are remarkable.

Personally I think serious scientific study under controlled conditions by independent third parties would be required to see which bits fall under true decompression advances (doubtlessly some would) and which bits can be explained otherwise, e.g. by weeding out the "average Joes" who are prone to DCI at an early stage leaving only non-statistically representative "survivors", or by superior fitness (and hence vascularization) or by e.g. Dr Powell's interesting data n post-dive exercise and DCI (which I think is highly interesting).

This means controls, this means people of differing physical shapes etc. All this is rather detrimental to the efficient mission-oriented nature of the WKKP's work, and it's their show, so I understand if they don't feel obliged to redo their challenging dives under such circumstances.

But until then, it really is very strange to pull out semisaturation dives in caves and project the results in other areas.

I do understand Rob's initial response, as the black-and-white cheerleader-type threads do grate after a while.

And finally, I do subscribe to the bubble model theories myself, and therefore dive VPM-B whenever possible. Which, BTW, I have no commercial interest or stake in.

 

[cdennyb]

Gentlemen, my question and ensuing remarks surrounding that question were aimed at these points of interest and I totally disregarded the past 50 years of advancemnets when I asked it...

1-Subject was basically related to sport diving and the use of the Navy tables like my instructor used in 1976 when I got my AOW card.
2- The profiles developed using V-Planner and the time required for the dive to be completed vs. the Navy tables on just about every dive you could calculate are significantly different.
3- I was meaning to compare the Navy Tables (developed as the Bible of Deco) that basically every sport diver has used back when I was certified AOW, vs the Techincally Advanced V-Planner VPM and VPM-B models or others for that matter.
4- I was NOT trying to develop a confrontation between the "who's best" of the latest software and bubble model programs, just trying to find out if it's possible (with all the various models and programs out there with their corresponding theories) that the sport divers will be presented with a "wheel" or table card that more closely reflects the advancments of these latest models.

Please, gentlemen, calm yourselves...
I agree with most of you that the available programs are far superior than the old Navy Tables, even though the tables were used for decades with minimal injuries. Deco theory and the programs are an evolving critter, Keep in mind the track record of the WKPP and the quanity of their rogue dives which had zero reported DCS incidents, and comapre that to the navy. The numbers speak for themselves.

I just wondered how long it would be before the agencies adopted one of the models and developed the corresponding plastic card or cards to reflect this evolution.
thanks to all.

sorry if I enraged anyone.

db

 

[KLD]

The NAUI RGBM (bubble) Plastic Tables are "out" a year and
a half, and used in all basic classes -- 9 plastic tables for air,
EAN32, EAN36 for altitudes from sea level - 2000 ft, 2000 ft -
6000 ft, and 6000 ft - 1000ft for rec (no deco) diving. They
are furnished in student kits for air and nitrox, and are
incorporated into all training material, books, CDs, videos, etc.
Rules are printed on the back, and backup light deco
is outlined. Tables call for a 1 minute deep stop
at 1/2 maximum depth, and then 2 minute shallow stop
in the 15 fsw zone for all dives beyond 40 fsw, and a 2
minute shallow stop for all dive less than 40 fsw.

This came out of the NAUI Deep Stops Workshop in Tampa
a year and a half ago (Feb, 2003)

So the answer is "it happened a year and half ago"
as far as plastic bubble model tables for rec diving.

KLD

Gentlemen, my question and ensuing remarks surrounding that question were aimed at these points of interest and I totally disregarded the past 50 years of advancemnets when I asked it...

1-Subject was basically related to sport diving and the use of the Navy tables like my instructor used in 1976 when I got my AOW card.
2- The profiles developed using V-Planner and the time required for the dive to be completed vs. the Navy tables on just about every dive you could calculate are significantly different.
3- I was meaning to compare the Navy Tables (developed as the Bible of Deco) that basically every sport diver has used back when I was certified AOW, vs the Techincally Advanced V-Planner VPM and VPM-B models or others for that matter.
4- I was NOT trying to develop a confrontation between the "who's best" of the latest software and bubble model programs, just trying to find out if it's possible (with all the various models and programs out there with their corresponding theories) that the sport divers will be presented with a "wheel" or table card that more closely reflects the advancments of these latest models.

Please, gentlemen, calm yourselves...
I agree with most of you that the available programs are far superior than the old Navy Tables, even though the tables were used for decades with minimal injuries. Deco theory and the programs are an evolving critter, Keep in mind the track record of the WKPP and the quanity of their rogue dives which had zero reported DCS incidents, and comapre that to the navy. The numbers speak for themselves.

I just wondered how long it would be before the agencies adopted one of the models and developed the corresponding plastic card or cards to reflect this evolution.
thanks to all.

sorry if I enraged anyone.

db

 

[rossh]

I just wondered how long it would be before the agencies adopted one of the models and developed the corresponding plastic card or cards to reflect this evolution.
thanks to all. db

IANTD uses the VPM-B in all it's latest courses, and has the tables on plastic cards. They came out last year as well.

V-Planner program with the VPM-B.

Regards
--
Ross H

 

[cdennyb]

Thanks guys. I was really curious and had a bet on how long the industry "lagged" on making this available. (I won the bet-my answer was about a year or two behind technology)
I would think also that soon in the future we'll see deco tables based on body fat %, total body weight, etc. and actually be able to do the optimum deco time depending on our physical attributes as well as the program math models.

That leads to another question from the phd's out there who know a hell of a lot more on this subject than I do!

Q: Does a heavy (say in the 250-300# range) overweight (high body fat) individual take more time to decompress from the same dive that I do 9@125# with 4% BF)?

db

 

[MonkSeal]

I would think also that soon in the future we'll see deco tables based on body fat %, total body weight, etc. and actually be able to do the optimum deco time depending on our physical attributes as well as the program math models.

No, that would leave too many room for subjective judgement.

Does a heavy (say in the 250-300# range) overweight (high body fat) individual take more time to decompress from the same dive that I do 9@125# with 4% BF)?

Yes, because off-gassing is done by perfusion (blood circulation) and poorly vascularised tissue (like fat) off-gasses slower.

 

[KLD]

DB,

Physiological factors such as age, sex, fat index, workload,
cardiovascular capacity, water temperature, etc feed
crucially into diving staging regimens. These factors are
called J-factors (USN early nomenclature), and attempts
have been made to roll data over them statistically in the
past by military and commercial sectors. Today, this
is also being done by your favorite meter manufacturer.
Theory here is much more difficult to do then dissolved
gas transfer and bubble mechanics, and tends to rely
on "risk functions" linked to measurable variables and
test data. But once done, this data can then be run
thru the staging algorithm so staging variables (M-values,
temperature, halftimes, separated bubble volumes, etc)
can be appropriately tuned to the model plus risk.

Expect much more in the future along these lines.

MonkSeal pointed out a fairly well accepted physiological
J-factor.

Best,

BW

Thanks guys. I was really curious and had a bet on how long the industry "lagged" on making this available. (I won the bet-my answer was about a year or two behind technology)
I would think also that soon in the future we'll see deco tables based on body fat %, total body weight, etc. and actually be able to do the optimum deco time depending on our physical attributes as well as the program math models.

That leads to another question from the phd's out there who know a hell of a lot more on this subject than I do!

Q: Does a heavy (say in the 250-300# range) overweight (high body fat) individual take more time to decompress from the same dive that I do 9@125# with 4% BF)?

db