Decompression Theory

[Storker]

Highly recommend you read Deco for Divers by Mark Powell, if you haven't already.

My copy still suffers from the fascination for deep stops. Has the latest edition been updated to reflect current knowledge?

 

[tursiops]

My copy still suffers from the fascination for deep stops. Has the latest edition been updated to reflect current knowledge?

Which edition/date is yours?

 

[Storker]

Which edition/date is yours?

2012. Seems like 1st edition, 2nd print.

The (in)famous NEDU study which kinda torpedoed the deep stop fascination was published in 2006, but its impact probably wasn't very significant until a few years later. Cfr the dates on the deep stop discussion threads here and on other forums.

Science moves slowly, and that's good.

 

[EFX]

2012. Seems like 1st edition, 2nd print.

You have the same edition I have. I believe it's the first edition. Inside the cover it says it was first published in 2008 and it was reprinted in 2009, 2010, and 2012. There was another thread (I can't find it) where someone mentioned the second edition has the words "second edition" on the front cover but I am not absolutely sure.

 

[DavidFL]

... the second edition has the words "second edition" on the front cover but I am not absolutely sure.

I can confirm my most recent copy has a red triangle in the lower right corner of the cover that says "SECOND EDITION" in white-on-red.

The copyright page says:
First Published 2008
Reprinted 2009, 2013
Second Edition 2014
Reprinted 2016

[I have two copies because the earlier one was autographed by Mark; I lost it for awhile; ordered a second copy; then found the first one].

The second reprint of the second edition acknowledges the NEDU study but still pretty favorably endorses deep stops.

 

[tursiops]

I can confirm my most recent copy has a red triangle in the lower right corner of the cover that says "SECOND EDITION" in white-on-red.

The copyright page says:
First Published 2008
Reprinted 2009, 2013
Second Edition 2014
Reprinted 2016

[I have two copies because the earlier one was autographed by Mark; I lost it for awhile; ordered a second copy; then found the first one].

I have this same 2nd edition, and it is still overboard on deep stops. The references have nothing newer than 2005, so the book cannot be up-to-date, especially on the NEDU study (2008, 2011, 2013) and its aftermath. To be fair, Powell begins to bring us up to date in 2018 with Delving Deeper into Deep Stops - Divernet where he concludes with "Some of the advice given over the past few years has clearly been introducing stops that are too deep. However, a knee-jerk reaction to say that “deep stops are bad” would be to swing too far the other way, and we should be careful not to throw the baby out with the bathwater." He obviously feels less strongly about the negative value of deep stops than many do today, but maybe he is just -- unsurprisingly -- moving slowly away from his own publication.

 

[Storker]

maybe he is just -- unsurprisingly -- moving slowly away from his own publication.

Powell is a scientist. A real one. Scientists can't help not to err on the side of caution. It makes progress slower, but a lot safer.

 

[boulderjohn]

Powell begins to bring us up to date in 2018 with Delving Deeper into Deep Stops - Divernet

To the best of my knowledge, that was the first time he departed from his "deep stops are great" philosophy. Anything printed before that will have his prior beliefs.

 

[KenGordon]

2012. Seems like 1st edition, 2nd print.

The (in)famous NEDU study which kinda torpedoed the deep stop fascination was published in 2006, but its impact probably wasn't very significant until a few years later. Cfr the dates on the deep stop discussion threads here and on other forums.

Science moves slowly, and that's good.

The NEDU report has a July 2011 date and claims to cover work from 2005 to April 2011.

The enormous arguments took a couple of years to properly kick off, eg Deep stops debate (split from ascent rate thread)

If you read deco posts from the late 2000s you will find that deep stops are the Shearwater Teric of the day. They were the accepted wisdom.

 

[KenGordon]

To the best of my knowledge, that was the first time he departed from his "deep stops are great" philosophy. Anything printed before that will have his prior beliefs.

I have done courses with Mark and I don’t think he pushed deep stops. Quickly skimming Deco for Divers just now I need to be reminded where he says deep stops are better.