How to properly assess the relative conservatism of various algos/computers for Rec divers?

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The Seac Guru is a rebranded Ratio iDive Easy. It runs ZH-L16B, most liberal setting is 93/93, I would have expected it to be at least as liberal as the Garmin running 45/95. I'm not at all sure the Suuntos were set on P-2
 
Hi Jay,
I've attached two articles from Divernet. In the Sep 2018 article, the diver compares a Suunto to a Scubapro. On the second dive the Suunto provides the longer NDL, but when it goes into deco, it recommends a longer decompression profile! The second article from 2009 reads like a horse race (Melbourne cup?). The computers are not necessarily current but the algorithms are the same today. Its very interesting how the "liberal" Oceanic DSAT performs in deco.

Many thanks for posting those studies. As someone who works in open-source/academic/medical research, my first reaction to questions about almost any closed source dive computer -- and this kind of comparative study -- is that the use of unpublished algorithms with unspecified manufacturer's deviations from experimental models means that any comparison or conclusion is little more than a series an anecdotes, and far from comprehensive. While the studies look impressive, there's no way to tell what's going on inside each computer, and no way to know if there would be significantly different values (ie., deco obligation, dramatically different 2nd dive NDLs, etc) as a result of minor deviations in the test (ie., +/- 1minute at any given depth).

I wonder if anyone (DAN?) has data on DCS events and dive computers, to see if there's any statistically significant correlation with the make/model of computer (and any changes from default settings).

The overall difference between the Oceanic DSAT+ model and the others was interesting.

However, the thing that jumped out most for me in the published study was this statement in the introduction, offered as support for the study (ie., almost certainly taken from their grant application):

The case has been reported of a diver who, following the closure of a PFO, had set their computer to calculate decompression at an heightened altitude but also employed a less conservative version of the decompression software. The diver was unaware of the impact the alterations made and, as a result of improper dive management, the computer locked up on surfacing. The diver continued diving with a new computer clear of any prior pressure/time exposure and, as a consequence, they experienced a relatively severe episode of DCS, with post-treatment relapse and significant sequellae. It was suggested in that report that a better knowledge of the implications of employing some of the adjustable computer safety features may have prevented the DCS event.​

In other words, the diver didn't know how to use their equipment and then directly violated training & standards (ie., switching computers during a series of repetitive dives), and suffered DCS. I'd suggest that simply not acting stupid may have prevented the DCS event, regardless of the computer, settings, or medical history.
 
...I wonder if anyone (DAN?) has data on DCS events and dive computers, to see if there's any statistically significant correlation with the make/model of computer (and any changes from default settings)...


Hi @rmssetc

DAN has been running Project Dive Exploration and the expanded, Database of Dive Exposure and Dive Outcomes, for quite a while.
upload_2018-11-15_13-14-32.png

upload_2018-11-15_13-14-57.png

The coming soon message has been posted for several years. I would love to see results/publications coming from this project
 
I'd suggest that simply not acting stupid may have prevented the DCS event, regardless of the computer, settings, or medical history.

If we all were not stupid, finding audience for their studies would be a problem for many more than just scubalabs.
 
https://www.shearwater.com/products/peregrine/

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