View Full Version : New introduction to Decompression Theory book available
Mark Powell
19-11-2008, 08:37
Deco For Divers by Mark Powell was launched last weekend at the EuroTek.08 conference.
The book is aimed to be an overview of decompression theory, starting with the very basics such as the history and principles of decompression. It then moves through the practical applications of decompression for Air and Nitrox diving as well as the implications for decompression sickness. It then goes on to cover deep stops and bubble models. Finally, for those interested it, covers the implications of Trimix on decompression and some of the alternative decompression models available today.
It is intended for any diver who is interested in what happens when they go underwater. As ALL dives are decompression dives then it is intended for the recreational diver as much as the technical diver. In particular any Dive Leader or Instructor should be aware of many of the ideas in this book. It also covers the theoretical basis of the BSAC-88 tables and dispells many of the myths that have built up over these tables.
The book has taken about 4 years from start to finish. In fact it took about 2 1/2years to write and then another 18 months to work through the process of turning it into something suitable for publication.
You can see more details on the book, view a sample chapter and order online at Deco For Divers by Mark Powell (http://www.dive-tech.co.uk/deco for divers.htm)
It is also avalable from Amazon.
I've also included below some quotes from various experts who reviewed the book.
This is a truly remarkable book which covers all the various theories of decompression and ascents for divers in a most readable and understanding manner. There is no other comprehensive book on decompression to my knowledge which is so easy to read and understand by the average recreational or technical diver.
Peter B. Bennett, Ph.D., D.Sc. Executive Director, UHMS. Emeritus Professor of Anesthesiology, Duke University Medical Center. Founder & 1st President, DAN
This is the most comprehensive and well-written text I've seen that attempts to explain decompression theory to divers.
Dr Richard Vann Assistant Research Professor in Anesthesiology, Safety Officer and Director of Applied Research at the Duke Hyperbaric Center, and Vice President for Research at DAN.
This book is a "must read" for those who have ever wondered about decompression tables and how they are created. It is a straight forward book and devoid of technical jargon. It starts with the scientific giants who developed the physics of the gas laws and the physiology of diving and ends with M-values and tissue bubbles. For the curious diver – and all divers should be – it will be money well spent!
Michael R. Powell, MS, PhD. NASA (retired), Medical Sciences Division, Johnson Space Center, Texas
I've seen a copy of this and it really does look good. Prior to this you had to read dozens of sources to build up a comprehensive view of deco theory and it's really nice to have it all in one place.
Janos
We were really pleased that this was launched at EuroTek.08 last week. I managed to get my sticky paws on one for about 5 minutes and it's now on my Christmas present list. Mark's done a great job in explaining deco theory in a matter of fact way so even I can understand it, so it ought to be added to the First Class Diver Reading List.
ChristianG
23-11-2008, 15:42
First Class Diver Reading List.
Sorry, I don't believe I qualify. ;) :rolleyes: :p :confused:
I couldnt wait till Xmas, so orderd mine today... ;)
I couldnt wait till Xmas, so orderd mine today... ;)
Got mine in the post today.... :D ...... and some geezer has scralwed all inside the cover....:rolleyes: ......... Ah well, looks a good read.
Where's me glasses..... :cool:
Mike Rowley
26-11-2008, 16:40
We were really pleased that this was launched at EuroTek.08 last week. I managed to get my sticky paws on one for about 5 minutes and it's now on my Christmas present list. Mark's done a great job in explaining deco theory in a matter of fact way so even I can understand it, so it ought to be added to the First Class Diver Reading List.
I am confused as to why you think a book on decompression theory should be on the reading list for FCD.
In recent years FCD exam has evolved to become an advanced dive management exam with a low level project dive and small boat handling/navigation/position fixing, geared primarily as a pre-requisite for NI. The diving requirements on the FCD exam would not put any strain on the average Sports Diver. It would appear that it is quite acceptable for someone to turn up at the practical exam and announce that they are not prepared to dive to deeper than 25m and still pass. I understand that ERD is no longer a pre requisite for the exam. Given this why would a FCD need to know anything about modern decompression theory? Surely the correct place for this to be is in the material for the BSACs highest diving qualification, the Advanced Mixed Gas Diver. The subject is already covered in some detail here.
The debate should really be about whether FCD is relavant or credible in its present form. If it became an elite high level diving certification again then I would agree with you but not in its present recreational level form.
I am confused as to why you think a book on decompression theory should be on the reading list for FCD.
- A fifth of the FCD theory exam is on decompression.
- Decompression is of interest to those who don't dive particularly deep.
In recent years FCD exam has evolved to become an advanced dive management exam with a low level project dive and small boat handling/navigation/position fixing, geared primarily as a pre-requisite for NI. The diving requirements on the FCD exam would not put any strain on the average Sports Diver. It would appear that it is quite acceptable for someone to turn up at the practical exam and announce that they are not prepared to dive to deeper than 25m and still pass. I understand that ERD is no longer a pre requisite for the exam. Given this why would a FCD need to know anything about modern decompression theory? Surely the correct place for this to be is in the material for the BSACs highest diving qualification, the Advanced Mixed Gas Diver. The subject is already covered in some detail here. But as I'm qualified to 100m, and AMG is 80m, does that make me a better diver? ;) Personally my toughest and most demanding course to date was my CCR cave course
The debate should really be about whether FCD is relavant or credible in its present form. If it became an elite high level diving certification again then I would agree with you but not in its present recreational level form.
I agree that's an interesting debate. I'm thinking about FCD next year, mainly because everyone I know who has done it has enjoyed it.
Janos
I agree that's an interesting debate. I'm thinking about FCD next year, mainly because everyone I know who has done it has enjoyed it.
Janos
Which is probably the best reasson to do it - 'its fun' :D
Iain.
Mike Rowley
26-11-2008, 17:21
- A fifth of the FCD theory exam is on decompression.
- Decompression is of interest to those who don't dive particularly deep.
But as I'm qualified to 100m, and AMG is 80m, does that make me a better diver? ;) Personally my toughest and most demanding course to date was my CCR cave course
I agree that's an interesting debate. I'm thinking about FCD next year, mainly because everyone I know who has done it has enjoyed it.
Janos
You miss my point entirely Janos. The fact that a significant proportion of the theory exam deals with decompression is not my issue. My question relates to whether it is relevant on an exam that requires so little in terms of diving. Worth a debate don't you think?
You miss my point entirely Janos. The fact that a significant proportion of the theory exam deals with decompression is not my issue. My question relates to whether it is relevant on an exam that requires so little in terms of diving. Worth a debate don't you think?
To paraphrase to check that I've understood - but are you saying that the level of theory knowledge required is beyond the level of practical knowledge required?
Janos
Mike Rowley
26-11-2008, 17:42
To paraphrase to check that I've understood - but are you saying that the level of theory knowledge required is beyond the level of practical knowledge required?
Janos
Beyond the level of practical diving skills required.
It would appear that it is quite acceptable for someone to turn up at the practical exam and announce that they are not prepared to dive to deeper than 25m and still pass. I understand that ERD is no longer a pre requisite for the exam. Given this why would a FCD need to know anything about modern decompression theory?
The reason I suggested that it ought to be considered for the list is that it will help fill in gaps, and makes for a more rounded, educated diver, because I do feel that a First Class Diver needs to have a good breadth of knowledge.
Dave Whitlow
26-11-2008, 23:01
The reason I suggested that it ought to be considered for the list is that it will help fill in gaps, and makes for a more rounded, educated diver, because I do feel that a First Class Diver needs to have a good breadth of knowledge.
I am about half way through the book at the moment and it seems a well researched and well presented book which, despite the technical nature of the subject, is easy to read and understand.:o
I did find it interesting that Mark was unable to find any research to support the assertion that reverse profile dives are a bad thing, although it is something we have all been taught, and wonder when that will debated on this forum :eek:
Roz, my only disagreement with you is that I'd extend the reading recommendation to anyone considering decompression dives, instructing, or mixed gas diving.
I am about half way through the book at the moment and it seems a well researched and well presented book which, despite the technical nature of the subject, is easy to read and understand.:o
I did find it interesting that Mark was unable to find any research to support the assertion that reverse profile dives are a bad thing, although it is something we have all been taught, and wonder when that will debated on this forum :eek:
Roz, my only disagreement with you is that I'd extend the reading recommendation to anyone considering decompression dives, instructing, or mixed gas diving.
I'm not quite as far as Dave into the book, but I'd have to say this book is a must have for any diver. I dont even think it matters if they are intending to do deco diving, or not.
What I mean by that is the book is neatly sectioned to meet the needs/skills of all divers from OD upwards. Its in plain english, easy to read and IMHO it would complement any diver training, even if only to spell out the risks involved and that decompression diving is not an exact science.
I did find it interesting that Mark was unable to find any research to support the assertion that reverse profile dives are a bad thing, although it is something we have all been taught, and wonder when that will debated on this forum :eek:
I think that should have read "wonder when that will debated again on this forum"
Mike Rowley
27-11-2008, 10:27
The reason I suggested that it ought to be considered for the list is that it will help fill in gaps, and makes for a more rounded, educated diver, because I do feel that a First Class Diver needs to have a good breadth of knowledge.
I totally agree Roz, I also think a FCD should have a high level of diving skills and ability. There is no point being able to talk the talk if you can't walk the walk. I would suggest this is where the imballance lies.
I believe the role of a FCD is to act as a role model within the club environment. If you are a crap diver then that sort of misses the point, doesn't it? A FCD should be someone who has a bredth of knowledge that can be accessed by the rest of the club and a skills set that is completely nailed for the type of diving the FCD does. Which does not have to be deep and dark.
Mike Rowley
27-11-2008, 16:45
Which does not have to be deep and dark.
What does it mean in your opinion and what do you mean by deep?
Mike Rowley
27-11-2008, 17:10
Just been looking at my old log book, amongst other pre-requisites for FCD it states;
"Submit properly certified log book showing a minimum of 100 dives under varying conditions. A proportion of these dives should show reasonable experience of depths greater than 30m."
The briefing notes for the practical exam stated amongst other things that you had to;
"be prepared to lead a dive to and display confidence and competence at a depth of down to 50m if required."
That was in 1981.
Just been looking at my old log book, amongst other pre-requisites for FCD it states;
"Submit properly certified log book showing a minimum of 100 dives under varying conditions. A proportion of these dives should show reasonable experience of depths greater than 30m."
Not adding much myself, but is that just not an experienced modern sports diver ?
The briefing notes for the practical exam stated amongst other things that you had to;
"be prepared to lead a dive to and display confidence and competence at a depth of down to 50m if required."
That was in 1981.
in 1981 were people doing 50m dives or 50m bounces ?
I started a lot later in 1988, and in those days we were popping down to have a look and then coming up (a bit fast ;-) and then getting out the water.
A 50m dive was actually quite easy if you didn't get narked, my "bottom time" on a 50m dive would now be 20 or so minutes greater.
maybe everyone elses "50m" dives were proper ones in those days, but must people didn't have access to the kit surely ? (good suits, high pressure cylinders etc)
Tony
iain1965
27-11-2008, 18:18
Sorry to interrupt guys, but has anyone else noticed that this thread was started purely and simply for this guy to unashamedly plug his own book. Surely if it was that good there would be rave reviews about it in every UK diving magazine and everyone would already have it.
Just my opinion, if anyone wants to bite feel free but I won't respond. ;)
Iain
It was only launched at EuroTek.08 11 days ago.....the magazines don't work that fast......and if the Mods thought this an inappropriate posting, believe me, it would have been swiftly removed.
Adrian Kelland
27-11-2008, 18:55
Sorry to interrupt guys, but has anyone else noticed that this thread was started purely and simply for this guy to unashamedly plug his own book. Surely if it was that good there would be rave reviews about it in every UK diving magazine and everyone would already have it.
Just my opinion, if anyone wants to bite feel free but I won't respond. ;)
Iain
There are some pre-review comments on the book by some high-falutin scientic bods. If they like it, then it scores more than a magazine comment for me.
However I've been waiting a while for this book, so I bought it off the shelf. No pressure sales.
Adrian
Mike Rowley
27-11-2008, 19:16
There are some pre-review comments on the book by some high-falutin scientic bods. If they like it, then it scores more than a magazine comment for me.
However I've been waiting a while for this book, so I bought it off the shelf. No pressure sales.
Adrian
Well, I've bought it but then, I'm interested in these things and it is relevant to my diving.
Adrian Kelland
27-11-2008, 19:20
Well, I've bought it but then, I'm interested in these things and it is relevant to my diving.
Likewise, if to a lesser extent.
Mike Rowley
16-02-2009, 14:02
Anyone seen Mark Ellyatt's review of this book in this months Diver mag? What do you think?
A bit like asking David Cameron's opinion of Gordon Brown I thought.:rolleyes:
Nope, not read the reivew. Read the book though & found it informative.
He gives it a right old slating. However I think he completely missed the point of the book- it's not a "how to do deco" or "which method is the best" but more of a "these are the theories".
Deco should be taught on a course, not learned from a book/internet.
HDeco should be taught on a course, not learned from a book/internet.
I disagree.
"Teaching deco" on a course will give you the instructor's view of deco. It won't give you the myriad conflicting opinions that go to make up decompression theory.
The only way to learn anything substantial about decompression theory is to spend a significant amount of time talking to practitioners skilled in the art. Attempting to condense that into a single course is doomed to failure.
An Introduction to Buhlmann course might be appropriate - as long as it didn't try to make claims about being "right" in any way...
Vic.
STEVE MC
17-02-2009, 13:21
I've got a copy and read it cover to cover (yes scousers can read:-) ), IMHO its a decent read, setting out each of the theory's on deco and what's happening to us while we are diving ,while avoiding the arguements about who's right or wrong about the deco they do.
Safe diving
Steve
From the review, that's what I think Mark was expecting, a "this is how you should do deco" course. Which is the one thing the book doesn't set out to be.
Teaching deco within the BSAC system gives a completely 88 view of deco which is then largely ignored. It would be nice to give people more of the background behind deco theory in whatever form, and debunk the impression that it's an exact science.
Teaching deco within the BSAC system gives a completely 88 view of deco which is then largely ignored. It would be nice to give people more of the background behind deco theory in whatever form, and debunk the impression that it's an exact science.
Sounds like what we really need is a library of decompression materials - both factual works, and more opinion-based, explanatory writings.
Fancy going halves on a wiki page?
Vic.
Paul Burgess
17-02-2009, 14:11
He gives it a right old slating. However I think he completely missed the point of the book- it's not a "how to do deco" or "which method is the best" but more of a "these are the theories".
Deco should be taught on a course, not learned from a book/internet.
Mark is someone who has spent a lot of time studying deco theory and putting it into practice. The book doesn't offer anything new for the learned - that is not its intention. As a result, I am not sure he would gain much from reading the book - perhaps a reason for his negative review.
On the other hand, for divers looking to move into technical or decompression diving, it is an excellent entry point as I don't think any other book collates and explains such a broad range of the different theories in one place.
I think that Mark Powell was wise to avoid putting down firm recommendations. I am with Woz in that I think the main training needs to come from an instructor, not a book. The book will help you learn from the instructor quicker (and also help you work out if he is talking lobblocks).
Sounds like what we really need is a library of decompression materials - both factual works, and more opinion-based, explanatory writings.
Fancy going halves on a wiki page?
Vic.Would love to. Let's Wiki!
Mike Rowley
17-02-2009, 14:24
From the review, that's what I think Mark was expecting, a "this is how you should do deco" course. Which is the one thing the book doesn't set out to be.
Teaching deco within the BSAC system gives a completely 88 view of deco which is then largely ignored. It would be nice to give people more of the background behind deco theory in whatever form, and debunk the impression that it's an exact science.
I'm sorry Woz but I must take issue slightly with you here. At recreational level BSAC uses the 88s certainly. At this level it is not necessary to complicate training with the myriad of decompression theories and models. Whatever your view of 88s may be they are simple to use and have a proven record in terms of the diving they are designed for. Interestingly, Mark states that the 88 model, in so far as we know what it may be based on, is not so far off modern thinking of combined models.
At Sports Mixed Gas level the student is introduced to modern decompression theory and is required to use a proven proprietry model to plan and execute dives to a maximum of 60m. At Advanced Mixed Gas level BSAC goes to some lengths to explain the various models and their origins in order to provide the diver with enough knowledge to make informed choices. There is no pressure to choose any specific model. This is an appropriate level to intoroduce this.
In terms of Mark Powell's book, I think it sets out the various models and their origins and evolution in a very clear and readable way. It gathers together much of the information that has only been available through academic papers or internet searches and puts it in one book. It separates descriptive text from mathematical modelling such that those who wish to gain an understanding can do so without clouding the learning process with complex maths they possibly would not understand or ever use. In short, it does what all good instructors should do - it makes the complex simple and understandable.
In my opinion only a fool would be prepared to state a particular model is the difinitive answer. There is not enough known about the physiological mechanisms involved to be this specific and even the academics still debate with caution since much of the theory is just that and we are the experimental guinea pigs. I certainly would not be brave enough to tell my students a particular model is the one they should choose above all others.
It is interesting that Mark Ellyatt has written a book and sells products based on his take on decompression theory. You may think that this has somewhat coloured his review.
I'm sorry Woz but I must take issue slightly with you here. At recreational level BSAC uses the 88s certainly. At this level it is not necessary to complicate training with the myriad of decompression theories and models. Whatever your view of 88s may be they are simple to use and have a proven record in terms of the diving they are designed for. Interestingly, Mark states that the 88 model, in so far as we know what it may be based on, is not so far off modern thinking of combined models.
At Sports Mixed Gas level the student is introduced to modern decompression theory and is required to use a proven proprietry model to plan and execute dives to a maximum of 60m. At Advanced Mixed Gas level BSAC goes to some lengths to explain the various models and their origins in order to provide the diver with enough knowledge to make informed choices. There is no pressure to choose any specific model. This is an appropriate level to intoroduce this.
In terms of Mark Powell's book, I think it sets out the various models and their origins and evolution in a very clear and readable way. It gathers together much of the information that has only been available through academic papers or internet searches and puts it in one book. It separates descriptive text from mathematical modelling such that those who wish to gain an understanding can do so without clouding the learning process with complex maths they possibly would not understand or ever use. In short, it does what all good instructors should do - it makes the complex simple and understandable.
In my opinion only a fool would be prepared to state a particular model is the difinitive answer. There is not enough known about the physiological mechanisms involved to be this specific and even the academics still debate with caution since much of the theory is just that and we are the experimental guinea pigs. I certainly would not be brave enough to tell my students a particular model is the one they should choose above all others.
It is interesting that Mark Ellyatt has written a book and sells products based on his take on decompression theory. You may think that this has somewhat coloured his review.Well- I agree completely with you there. Beyond recreational diving, deco is so untested that understanding the myriad of theories is much more important than at the recreational level. I don't think Mark Ellyatt's view could be taken as impartial. Mind you he's been bent more times than a paperclip.
Mark is someone who has spent a lot of time studying deco theory and putting it into practice..... I am not sure he would gain much from reading the book
:confused: :confused:
don't have the article here with me but... didn't it start off with "I read this book in the pot":rolleyes:
Mike Rowley
17-02-2009, 16:21
:confused: :confused:
don't have the article here with me but... didn't it start off with "I read this book in the pot":rolleyes:
Quite so Jim. According to his presentation at NEC he had a renal DCI and suffered renal failure after going to 200m on a planned dive to 130m. I understand his PO2 was in excess of 2.0 bar, I think he said he was running 10/52 diluent. Apparantly he delayed going to the chamber for 12 hours.:confused:
Just the very man I would think of first for an impartial book review, expert on DCI.:rolleyes:
Prehaps it was the chamber operator that gave him the book to read:D
I have to say I have enjoyed Marks book immensly. I think it more than achieves what it sets out to do, in a manor that most will be able to relate to.
Gareth
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