Dive Computer test at Divernet
If you are looking for a realistic in-water test of current dive computer models, this article might be something for you. Unlike the usual dive magazine reviews with glossy pictures and long extra-feature lists, this tester strapped 12 models on a board and took them diving in the Red Sea. The whole point of the exercise (apart from some pretty intense gadget fidgeting... ;-) was to observe the recommended deco stop schedule of the various computers once the dive had been extended past the no-stop point for that depth. The most cautious route was then followed up to the surface.
This 'rig' of computers was then photographed at regular intervals to capture the deco readings on each display, and are presented in the following table (split for convenience in two parts):
This is followed by the inevitable side-by-side review of the physical characteristics of all teste models, including a basic list of features as well as prices (in GBP) which are omitted here for obvious reasons (see above).
Unfortunately, the otherwise straightforward and interesting article also includes a paragraph on "deep stops", a.k.a. gradually ascending from maximum depth before heading more directly for the safety/deco stop depth. Since virtually any sports diver is probably familiar with that kind of dive profile (except for its new label) why discuss it in such an article? The argument offered is astonishing:
"Extreme deep-diving ichthyologist Dr Richard Pyle noted that if he made pauses in an ascent from a dive at a depth equal to around half the maximum pressure to which he had subjected himself, instead of ascending straight to the surface, and then repeatedly did the same thing again between there and the surface, he felt a lot better afterwards.
The idea is based on the theory that the human body can sustain a 50% reduced pressure change without suffering ill effects."
So now we await eagerly to read more about that "theory that the human body can better sustain a 50% reduced pressure change". Unfortunately, all the authors can offer here is of little use:
"Although this is not based on any other real scientific evidence, giving slow tissues time to off-gas in this way, even at the expense of faster tissues on-gassing, makes sense!"
Now what on earth makes more sense, things based on "real scientific evidence" or some arbitrarily designed rule of "stopping halfway will make you feel better"?
However, to be fair to Mr Pyle who apparently stands behind this "50/50" rule as it could be dubbed, I will point you to this site where he decribes his theory - and how he came to propose it - in full detail.
Returning to the scope of the dive computer test article, I would conclude that from a scientific and especially medical point of view, people should probably rather be advised to use the most conservative computer model employing the safest algorithm, and press this point as the main decisive factor (apart from display readability, maybe) for any dive computer purchase.
But of course we all know that this is neither the way how such purchases usually are being motivated, nor the way how "deco plan safety tests" are being performed and published, unfortunately.
This 'rig' of computers was then photographed at regular intervals to capture the deco readings on each display, and are presented in the following table (split for convenience in two parts):
This is followed by the inevitable side-by-side review of the physical characteristics of all teste models, including a basic list of features as well as prices (in GBP) which are omitted here for obvious reasons (see above).
Unfortunately, the otherwise straightforward and interesting article also includes a paragraph on "deep stops", a.k.a. gradually ascending from maximum depth before heading more directly for the safety/deco stop depth. Since virtually any sports diver is probably familiar with that kind of dive profile (except for its new label) why discuss it in such an article? The argument offered is astonishing:
"Extreme deep-diving ichthyologist Dr Richard Pyle noted that if he made pauses in an ascent from a dive at a depth equal to around half the maximum pressure to which he had subjected himself, instead of ascending straight to the surface, and then repeatedly did the same thing again between there and the surface, he felt a lot better afterwards.
The idea is based on the theory that the human body can sustain a 50% reduced pressure change without suffering ill effects."
So now we await eagerly to read more about that "theory that the human body can better sustain a 50% reduced pressure change". Unfortunately, all the authors can offer here is of little use:
"Although this is not based on any other real scientific evidence, giving slow tissues time to off-gas in this way, even at the expense of faster tissues on-gassing, makes sense!"
Now what on earth makes more sense, things based on "real scientific evidence" or some arbitrarily designed rule of "stopping halfway will make you feel better"?
However, to be fair to Mr Pyle who apparently stands behind this "50/50" rule as it could be dubbed, I will point you to this site where he decribes his theory - and how he came to propose it - in full detail.
Returning to the scope of the dive computer test article, I would conclude that from a scientific and especially medical point of view, people should probably rather be advised to use the most conservative computer model employing the safest algorithm, and press this point as the main decisive factor (apart from display readability, maybe) for any dive computer purchase.
But of course we all know that this is neither the way how such purchases usually are being motivated, nor the way how "deco plan safety tests" are being performed and published, unfortunately.
Labels: Cool Gear, Scuba Diving
posted by leptonyx at 18:57
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