A new Contentious Question...Is Deco an Art or a Science?

GLOC · July 3rd, 2006, 05:32 PM

Having started to get my feet wet in the deco world (non-GUE training, TDI) and reading the posts here it seems obvious that there is no definitive way to do deco as they are the edge of statistical data.

Where one profile seems to work for one person/team, might not for another. The recent posts regarding the profiles in the Red Sea (Hassan?) and O2 recompression is a classic - one team might be able to push a profile as they are used to it, whereas another team would be bent to hell.

So, in the same way as photography can be thought of as art because it is pleasing to the eye and brings forward emotive responses, there is some science behind what makes a decent picture (rule of thirds, DoF etc). What are the views on deco, is it an art form or is it a science....or is it a mixture of both? And equally as important, why?

Pulls pin, stands back and lobs into the crowd.

TobinGeorge · July 3rd, 2006, 05:56 PM

Lots of "Science" in the theories, lots of art in the application and execution.

Tobin

***ericfine50*** · July 3rd, 2006, 06:01 PM

Well said Tobin - That was what I was thinking. The science behind it is always evolving (02 deco to He in the deco mixs for example) execution - That is an art. Everyone's body is different and the body will tell you if your schedule worked or you need to rethink it.

Chrisch · July 3rd, 2006, 11:10 PM

While you might think of the act - maintaining a stop, shooting a bag etc - as an art, decompression prediction is a science, albeit an inexact one.

I have worked with statistics for many years and after a lot of time and effort I think I am just beginning to understand them at their simplest. Unless you know the basics statistics are at best misleading. Most folk do not know the basics.

Furthermore human physiology is also an inexact science. There is no test for DCI and its symptoms can be confused with other maladies even by highly experienced and skilled medical personnel.

No mathematical model can accurately predict random events and DCI is to some extent random. Microbubbles may cause no problems or a single bubble can bend you. This can be explained by science - chaos theory is a perfect explanation.

Therefore one is left with the inexact and dissapointing "science" of statistical analysis. This brings with it the inate fault that at some point the statistical model will predict the opposite of the actual results.

Fortunately this is rare and O2 therapy is usually effective.....

Chris

*Hassan Adly* · July 4th, 2006, 12:26 AM

Hello,

When I pick up a book to read about decompression, I don't generally reach for the ones written by decompression "scientists". I have books and texts by Bruce Wienke, Eric Baker, Buhlmann and others, and although I got them intending to study them I never really get beyond a few pages in any of them. The reason is that they do very little to help me learn how to decompress more effectively.

What does help is information gotten from people who have done enough dives, and gotten bent often enough to be able to explain what works for them. That's why so many divers swear by George Irvine's articles. They aren't necessarily based on science, but rather on huge experience accumulated over many years of extreme diving.

A mechanic needs to understand that when combustion occurs, gas expands. He doesn't need to be able to recite the second law of thermodynamics. What differentiates a talented mechanic from an untalented one is creativity and ingenuity, not the number of PhD's they have. The same goes for divers.

Is decompression an art? If art means that the result is based on individual skill and learning to "feel" the decompression curve, rather than the result depending on a diver following a strict set of rules (such as fixed runtime plans spit out by computer programs), then I would say that it is art. There are as many ways to decompress as there are diving scenarios. Learning to use the tools available to create and execute the most effective strategy for decompression is in my opinion an art form.

lizardland · July 4th, 2006, 12:51 AM

A bit of both, a lot of scientific research has gone into finding out precisely how random deco can be.

Rich Pyle has probably spent more time on deco than most of us have spent underwater and as he says, I'm a firm believer that it's a chaos system.

Deco is a "best guess", if you want to call that science then fine.

*Clare Gledhill* · July 4th, 2006, 01:24 PM

I think your view on this may be coloured by how you were taught deco in the first place.

Seems to me that there are always more ways to skin a cat than first appear. Whilst the amount of decompression required to reduce the staistical likelihood of getting bent to a manageable level is easily (if not contensiously) arrived upon, there is still a great deal of room for manovure as to how this can be achieved.

On a TDI course that I did deco shape was designed by computer programme. Now I am not in any way saying that students were not encouraged to look at the data produced to give it a 'common sense check' to make sure that results were within expected parameters - but where the stops were and how long they were for was designed by the programme - and whatever 'factors' the diver entered at the start.

On a GUE course we were encouraged to think about the shape of the deco, how each stop was working (emphasising O2 or gradient or both). Example dives were discussed with the pattern of stops we came up with discussed on a 'does that feel right' basis.

I believe that "feel" is actually - on closer analysis maths - ratios to produce the curve required (S or phi dependant on whether you are utilising O2 or gradient). But maths in the way that music is maths - and how the ratio of some combinations of frequecies produce more asthetic outcomes than others.

Some curves will give palpably better results for an individual than others - perhaps we could see 'art' in this instance as the learned application of common sense and experience.

Of course, the alternative, to rip off another diver's oft quoted phrase 'it's all bollox

'

lizardland · July 4th, 2006, 02:32 PM

Quote: (Originally Posted by Clare Gledhill)

I think your view on this may be coloured by how you were taught deco in the first place.

What does worry me is teaching that deco is precise, that if you do 15min of deco you will be fine but if you do 14min of deco you will be ok. It is nowhere near as finite a system as that.

Quote:

Seems to me that there are always more ways to skin a cat than first appear.

There are two sayings about deco that I think are very true: what works, works and never take advice from someone who isn't willing to push your wheelchair.

Quote:

Whilst the amount of decompression required to reduce the staistical likelihood of getting bent to a manageable level is easily (if not contensiously) arrived upon, there is still a great deal of room for manovure as to how this can be achieved.

Most of the models arrive at similar deco times. Too much is made of deco for an individual dive, I think one of the things that is too easily forgotten about is what is happening to the body cumulatively. Commercial divers have better DCI rates than recreational divers and yet they show much worse long term problems. Go figure.

Quote:

On a TDI course that I did deco shape was designed by computer programme... On a GUE course we were encouraged to think about the shape of the deco

It all comes down to what you think is right. Anyone who goes into a course, whatever the agency, and comes away thinking that what they have been taught is right in every way is asking for trouble. Maybe it's the cynic in me but I didn't do any major deco before looking a hell of a lot more in depth at it than was covered in any course. You can't afford to listen to just one side. Deco will easily kill you, it is that serious.

Quote:

I believe that "feel" is actually - on closer analysis maths - ratios to produce the curve required (S or phi dependant on whether you are utilising O2 or gradient). But maths in the way that music is maths - and how the ratio of some combinations of frequecies produce more asthetic outcomes than others.

You could just as easily call it "experience". When you do enough diving, you know what works. It becomes reflex. That cannot be taught or learned anywhere else than in the water. You do get a feel for how your body is at any moment in time, in the water there is a "feel" to it.

Quote:

Some curves will give palpably better results for an individual than others - perhaps we could see 'art' in this instance as the learned application of common sense and experience.

Art is instinctive. I'd call it skill as it can be learned. Art cannot be learned, you can either do it or you can't.

Divingniknaks · July 4th, 2006, 04:02 PM

Quote: (Originally Posted by lizardland)

before looking a hell of a lot more in depth at it than was covered in any course. You can't afford to listen to just one side. Deco will easily kill you, it is that serious.

Just out of curiosity, where did you go to research ?

Cheers

Red Sea Explorer · July 4th, 2006, 04:58 PM

Hi All,

There is a lot of science about human physiology in every sport/hobby be it basketball, long distance running or diving. The sportsman/hobbyist needs to understand the general idea behind the science so he can understand his physiology. However, during the game or event the science is forgotten and we apply what works. More importantly, we apply what works for us.

As Clare pointed out there are many ways to skin a cat. There are a lot of people diving very different profiles. Some of those are in cold water and want to get out quick or want to get to the shallows. There are others who have tropics and do not care for the depth or time of the profile. Then again you have those who have funny looking caves and they have to push funny profiles to get through. I guess this is where the art comes in, it is the way the people adapt their knowledge or science to their environment.

I think decompression is best compared to a language. It has basic grammatical rules but can be used to satisfy many different applications. Different people may pronounce things differently and have different accents, but they are all speaking the same language. How proficient you become in this language depends on how much you use it. The environment where you use it dictates what accent you will have, i.e. what profiles you will pull.

All the tools, Ratio Deco, Software, Tables etc… these are all like the little dotted books we used when we were learning to read and write. Once you can speak the language you can do it without the aids. In Deco, with practice you will know what works best for you after you have tried it many times and paid attention to yourself after the dives to see how you feel and to see what changes affect you and how.

That being said it pays to be conservative not get too creative with the art of Deco. Else it will bite you in the ass, as we demonstrated in May.

July 3rd, 2006, 05:32 PM	#1 (permalink)
GLOC (Online) Moderator Join Date: Nov 2005 Location: Fleet, Hants Posts: 1,950	A new Contentious Question...Is Deco an Art or a Science? Having started to get my feet wet in the deco world (non-GUE training, TDI) and reading the posts here it seems obvious that there is no definitive way to do deco as they are the edge of statistical data. Where one profile seems to work for one person/team, might not for another. The recent posts regarding the profiles in the Red Sea (Hassan?) and O2 recompression is a classic - one team might be able to push a profile as they are used to it, whereas another team would be bent to hell. So, in the same way as photography can be thought of as art because it is pleasing to the eye and brings forward emotive responses, there is some science behind what makes a decent picture (rule of thirds, DoF etc). What are the views on deco, is it an art form or is it a science....or is it a mixture of both? And equally as important, why? Pulls pin, stands back and lobs into the crowd. __________________ Gareth Images of Life Photography DIR Team Foxturd Travels Underwater and Further Afar If you don't have the time to do something right, where are you going to find the time to fix it? - Stephen King

July 4th, 2006, 12:26 AM	#5 (permalink)
Hassan Adly (Online) GUE Instructor Join Date: Feb 2006 Location: Red Sea Posts: 286	Hello, When I pick up a book to read about decompression, I don't generally reach for the ones written by decompression "scientists". I have books and texts by Bruce Wienke, Eric Baker, Buhlmann and others, and although I got them intending to study them I never really get beyond a few pages in any of them. The reason is that they do very little to help me learn how to decompress more effectively. What does help is information gotten from people who have done enough dives, and gotten bent often enough to be able to explain what works for them. That's why so many divers swear by George Irvine's articles. They aren't necessarily based on science, but rather on huge experience accumulated over many years of extreme diving. A mechanic needs to understand that when combustion occurs, gas expands. He doesn't need to be able to recite the second law of thermodynamics. What differentiates a talented mechanic from an untalented one is creativity and ingenuity, not the number of PhD's they have. The same goes for divers. Is decompression an art? If art means that the result is based on individual skill and learning to "feel" the decompression curve, rather than the result depending on a diver following a strict set of rules (such as fixed runtime plans spit out by computer programs), then I would say that it is art. There are as many ways to decompress as there are diving scenarios. Learning to use the tools available to create and execute the most effective strategy for decompression is in my opinion an art form. __________________ Hassan Adly Red Sea Discovery "Today I will finally see the sea again, which will smell of salt, wind, sand - and the cold of winter. Finally I will not only travel on it but dive in it, again I will become water, a bird - and I will remember the feeling of gliding above the abyss" Elena Sundukova, tragically lost at sea, January 2007

July 4th, 2006, 12:51 AM	#6 (permalink)
lizardland(Offline) LCS Join Date: Nov 2005 Location: Evidently Chickentown Posts: 591	A bit of both, a lot of scientific research has gone into finding out precisely how random deco can be. Rich Pyle has probably spent more time on deco than most of us have spent underwater and as he says, I'm a firm believer that it's a chaos system. Deco is a "best guess", if you want to call that science then fine. __________________ Can you imagine drifting along in the sea with your mouth open and a load of f***ing plankton going in? You'd like it, would you? www.westons-cider.co.uk The Lot isn't the only place to dive: http://www.lulu.com/content/613554

July 4th, 2006, 01:24 PM	#7 (permalink)
Clare Gledhill (Online) GUE Instructor Site Admin Pacman Champion! Join Date: Nov 2005 Location: UK Posts: 1,540	I think your view on this may be coloured by how you were taught deco in the first place. Seems to me that there are always more ways to skin a cat than first appear. Whilst the amount of decompression required to reduce the staistical likelihood of getting bent to a manageable level is easily (if not contensiously) arrived upon, there is still a great deal of room for manovure as to how this can be achieved. On a TDI course that I did deco shape was designed by computer programme. Now I am not in any way saying that students were not encouraged to look at the data produced to give it a 'common sense check' to make sure that results were within expected parameters - but where the stops were and how long they were for was designed by the programme - and whatever 'factors' the diver entered at the start. On a GUE course we were encouraged to think about the shape of the deco, how each stop was working (emphasising O2 or gradient or both). Example dives were discussed with the pattern of stops we came up with discussed on a 'does that feel right' basis. I believe that "feel" is actually - on closer analysis maths - ratios to produce the curve required (S or phi dependant on whether you are utilising O2 or gradient). But maths in the way that music is maths - and how the ratio of some combinations of frequecies produce more asthetic outcomes than others. Some curves will give palpably better results for an individual than others - perhaps we could see 'art' in this instance as the learned application of common sense and experience. Of course, the alternative, to rip off another diver's oft quoted phrase 'it's all bollox ' __________________ Clare . "Keep away from people who try to belittle your ambitions....Small people always do that, but the really great make you feel that you too can become great." Interested in DIR dive training? Always happy to chat/answer questions so get in touch via PM or visit www.dirdiver.co.uk Last edited by Clare Gledhill; July 4th, 2006 at 01:27 PM.

July 4th, 2006, 02:32 PM	#8 (permalink)
lizardland(Offline) LCS Join Date: Nov 2005 Location: Evidently Chickentown Posts: 591	Quote: (Originally Posted by Clare Gledhill) I think your view on this may be coloured by how you were taught deco in the first place. What does worry me is teaching that deco is precise, that if you do 15min of deco you will be fine but if you do 14min of deco you will be ok. It is nowhere near as finite a system as that. Quote: Seems to me that there are always more ways to skin a cat than first appear. There are two sayings about deco that I think are very true: what works, works and never take advice from someone who isn't willing to push your wheelchair. Quote: Whilst the amount of decompression required to reduce the staistical likelihood of getting bent to a manageable level is easily (if not contensiously) arrived upon, there is still a great deal of room for manovure as to how this can be achieved. Most of the models arrive at similar deco times. Too much is made of deco for an individual dive, I think one of the things that is too easily forgotten about is what is happening to the body cumulatively. Commercial divers have better DCI rates than recreational divers and yet they show much worse long term problems. Go figure. Quote: On a TDI course that I did deco shape was designed by computer programme... On a GUE course we were encouraged to think about the shape of the deco It all comes down to what you think is right. Anyone who goes into a course, whatever the agency, and comes away thinking that what they have been taught is right in every way is asking for trouble. Maybe it's the cynic in me but I didn't do any major deco before looking a hell of a lot more in depth at it than was covered in any course. You can't afford to listen to just one side. Deco will easily kill you, it is that serious. Quote: I believe that "feel" is actually - on closer analysis maths - ratios to produce the curve required (S or phi dependant on whether you are utilising O2 or gradient). But maths in the way that music is maths - and how the ratio of some combinations of frequecies produce more asthetic outcomes than others. You could just as easily call it "experience". When you do enough diving, you know what works. It becomes reflex. That cannot be taught or learned anywhere else than in the water. You do get a feel for how your body is at any moment in time, in the water there is a "feel" to it. Quote: Some curves will give palpably better results for an individual than others - perhaps we could see 'art' in this instance as the learned application of common sense and experience. Art is instinctive. I'd call it skill as it can be learned. Art cannot be learned, you can either do it or you can't. __________________ Can you imagine drifting along in the sea with your mouth open and a load of f***ing plankton going in? You'd like it, would you? www.westons-cider.co.uk The Lot isn't the only place to dive: http://www.lulu.com/content/613554

July 3rd, 2006, 05:56 PM	#2 (permalink)
TobinGeorge (Online) New Member Join Date: Nov 2005 Location: Southern California Posts: 565	Lots of "Science" in the theories, lots of art in the application and execution. Tobin

July 3rd, 2006, 06:01 PM	#3 (permalink)
*ericfine50*(Offline) Moderator Join Date: Nov 2005 Location: MA Posts: 622	Well said Tobin - That was what I was thinking. The science behind it is always evolving (02 deco to He in the deco mixs for example) execution - That is an art. Everyone's body is different and the body will tell you if your schedule worked or you need to rethink it.

July 3rd, 2006, 11:10 PM	#4 (permalink)
Chrisch(Offline) Hogarthian Heretic Join Date: Dec 2005 Location: Brighton Posts: 104	While you might think of the act - maintaining a stop, shooting a bag etc - as an art, decompression prediction is a science, albeit an inexact one. I have worked with statistics for many years and after a lot of time and effort I think I am just beginning to understand them at their simplest. Unless you know the basics statistics are at best misleading. Most folk do not know the basics. Furthermore human physiology is also an inexact science. There is no test for DCI and its symptoms can be confused with other maladies even by highly experienced and skilled medical personnel. No mathematical model can accurately predict random events and DCI is to some extent random. Microbubbles may cause no problems or a single bubble can bend you. This can be explained by science - chaos theory is a perfect explanation. Therefore one is left with the inexact and dissapointing "science" of statistical analysis. This brings with it the inate fault that at some point the statistical model will predict the opposite of the actual results. Fortunately this is rare and O2 therapy is usually effective..... Chris

July 4th, 2006, 04:02 PM	#9 (permalink)
Divingniknaks(Offline) Resident purveyor of shiney kit.... Join Date: Nov 2005 Location: Midlands UK Posts: 1,038	Quote: (Originally Posted by lizardland) before looking a hell of a lot more in depth at it than was covered in any course. You can't afford to listen to just one side. Deco will easily kill you, it is that serious. Just out of curiosity, where did you go to research ? Cheers __________________ Phill ----------------------------- Salvo Lights, DirZone Gear , Frog Wings Dive ? http://www.divingniknaks.com

July 4th, 2006, 04:58 PM	#10 (permalink)
Red Sea Explorer(Offline) New Member Join Date: Jan 2006 Location: Red Sea Posts: 236	Hi All, There is a lot of science about human physiology in every sport/hobby be it basketball, long distance running or diving. The sportsman/hobbyist needs to understand the general idea behind the science so he can understand his physiology. However, during the game or event the science is forgotten and we apply what works. More importantly, we apply what works for us. As Clare pointed out there are many ways to skin a cat. There are a lot of people diving very different profiles. Some of those are in cold water and want to get out quick or want to get to the shallows. There are others who have tropics and do not care for the depth or time of the profile. Then again you have those who have funny looking caves and they have to push funny profiles to get through. I guess this is where the art comes in, it is the way the people adapt their knowledge or science to their environment. I think decompression is best compared to a language. It has basic grammatical rules but can be used to satisfy many different applications. Different people may pronounce things differently and have different accents, but they are all speaking the same language. How proficient you become in this language depends on how much you use it. The environment where you use it dictates what accent you will have, i.e. what profiles you will pull. All the tools, Ratio Deco, Software, Tables etc… these are all like the little dotted books we used when we were learning to read and write. Once you can speak the language you can do it without the aids. In Deco, with practice you will know what works best for you after you have tried it many times and paid attention to yourself after the dives to see how you feel and to see what changes affect you and how. That being said it pays to be conservative not get too creative with the art of Deco. Else it will bite you in the ass, as we demonstrated in May. __________________ You watch me switch. www.redseaexplorers.com