Ken's article in CDN

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Posted by MHK on November 26, 2007 at 20:21:12:


I thought it would be useful to provide a counterpoint to your recent article in CDN. I realize Dale will never publish anything from me so I thought I'd use this forum to provide a different perspective.

Let me start off by saying that I agree with the predicate of your analysis which is to say that if a diver puts all his eggs in the computer basket and then the computer takes a crap that most divers lack the wherewithal to compute NDL's and then should therefore sit out.

Where I part company with your thinking is that I'm against the idea of putting all the eggs in the computer basket to begin with. If we look at the progression of most divers, most start off learning about tables ( or atleast they used to ), and to that extent they have a basis for computing NDL's. As they gain in experience and expand their knowledge base, they come to learn that tables are artificially limiting, so most then learn about computers ( let'sput aside the wheel for purposes of a useful discussion ). When a diver purchases a computer most assume that it is the Holy Grail and they can extend NDL's well beyond the scope of tables and ceede all further thinking about NDL's and let the computer worry about multi-level profiles and RNT's. ( This is much more commonplace when diving Nitrox wherein divers don't even think about calculating CNS and/or OTU's ). This is where I have a problem with this approach. All too many divers assume that the computer isn't just another device that artificially limits NDL's so they abdicate all sense of responsibility and rely exclusively on the device to do all the thinking, and then as happened to you, when it fails the diver is left lacking critical information. As I noted, if the diver is in this position I don't disagree with you in that they should sit out. Where I'm taking issue is that I don't feel divers should be in this position in the 1st place and sadly the industry does a poor job teaching decompression theory, and as a result all too many divers find themselves in the very spot your article highlights; a failed computer during a multi-day dive trip and a choice between the lesser of 2 evils, sit out or dive using ad hoc, ill-advised dive plans. I'd prefer to see a greater effort within the industry to educate divers about decompression theory and a greater effort to create thinking divers that don't need to rely on devices such as computers to do the thinking for the diver. Moreover, when you consider the set-points and the conservation considerations built in to most in-water computer algorithms, most divers are surprised when they learn how diluted these M-values actually are. They are usually set for the lowest common denominator in diving, ie; the diver with no bouyancy control, the smoking diver, the obese diver, the diver with a PFO, etc. etc.

Decompression theory isn't anything to be afraid of, but the fear of the unknown is usually a natural cause for concern so I understand why many divers abdicate the responsibility to a computer, I'd just prefer to see educated divers that don't need to rely on such failure prone devices.


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