What Deco Algorithm do you use? (Poll)

[Nitrogenius]

buhlmann and vpm

Without any statement on the conservatism settings this comparison is somewhat meaningless..
Pointing out a huge difference in overall deco obligation is somewhat missing my point by the way..


This discussion is about distribution of stops..
Obviously deco approaches are only of a comparable conservatism when you keep the overall decompression time as your constant in your comparison..


Please make sure to look at apples and apples..


When you work with similar overall decompression times you will find that especially with your kind of diving (deep and long) the actual distribution of the decompression will not vary very much between the different deco approaches..
May I had not been clear what I meant and maybe it gets a bit clearer now..


Those differences in distribution are quite more substantial in the shorter Ocean "dip" deep diving..

Well, looking at Brian's example, ignoring over an hour of deco seems less than ideal.

good grief
pure polemics!


BTW it would clearly depend on the point of view whether it would be "ignoring half an hour" or adding half an hour..
What would GI3 think?


Never mind..
Fact is such differences in deco times are hardly comparable decompression approaches and any comparison in distribution of stops would be moot..

[PfcAJ]

BTW it would clearly depend on the point of view whether it would be "ignoring half an hour" or adding half an hour..

Go back a few pages and reference the nice full color poster I linked to.

[LiteHedded]

Without any statement on the conservatism settings this comparison is somewhat meaningless..
Pointing out a huge difference in overall deco obligation is somewhat missing my point by the way..


This discussion is about distribution of stops..
Obviously deco approaches are only of a comparable conservatism when you keep the overall decompression time as your constant in your comparison..


Please make sure to look at apples and apples..


When you work with similar overall decompression times you will find that especially with your kind of diving (deep and long) the actual distribution of the decompression will not vary very much between the different deco approaches..
May I had not been clear what I meant and maybe it gets a bit clearer now..


Those differences in distribution are quite more substantial in the shorter Ocean "dip" deep diving..





good grief
pure polemics!


BTW it would clearly depend on the point of view whether it would be "ignoring half an hour" or adding half an hour..
What would GI3 think?


Never mind..
Fact is such differences in deco times are hardly comparable decompression approaches and any comparison in distribution of stops would be moot..

these are the defaults in deco planner. 20/85 and i think +1
the max i can increase it to is +4 and vpm is still 52 minutes shorter.

[MORGAN]

Not being so much a computer and deco science geek as some, for most dives I just run my Petrel on GF 30/70 and do what it tells me. For deeper, longer, or trimix dives I cut backup tables in iDeco, as it uses the same algorithm as the Petrel and I can match the gradient factors.

I ascend very slowly from my last stop, and then do at least 5 minutes of "surface deco", lounging in indolence and sloth enjoying a few more minutes of zero gravity.

One of the great advantages of cave diving is a nice calm surface deco instead of surfacing to wind and waves, watching the dive boat pitch up and down, and trying to time the dive ladder so as not to get thumped on the head by it.

[Nix]

BVM(3) is readily available from Rubicon http://archive.rubicon-foundation.or...123456789/2258

[Nitrogenius]

these are the defaults in deco planner. 20/85 and i think +1
the max i can increase it to is +4 and vpm is still 52 minutes shorter.

defaults.. ok I see..
Well VPM +1 is known to be pretty aggressive..
And yes generally the overall conservatism settings and what is implied would tempt the diver to go fairly aggressive (like you say VPM still being 50 min shorter on +4 while + 4 would imply to be pretty conservative)
again my comment towards similarity given the nature of the deco combined with cave dives was totally geared at the distribution of stops due to load status in all tissues/compartments getting high..
Did you compare the starting depth of stops between the 20/85 and the +4, I bet they start getting close to each other.. Since you cannot raise the conservatism of VPN anymore raise the GF hi to get closer to the VPM overall time and compare the stops.. then raise the GF lo to say 50 (deco time will even shorten more if you do not lower the GF hi at the same time) and even with moving up to GF lo 50 I would bet that the overall profile (in regards to distribution of stops and where deco starts) will not look overly different..


and by the way.. I happily stand corrected.. but this is what I found..
So as far as the starting deep vs lo GF and its relation to VPM goes, it really makes not much difference with "typical" cave profiles..
When one uses VPM you want to make sure to get enough conservatism (i.e. overall deco time) but that is a complete different story..
I personally never used VPM one single day for diving and never will..

[Jax]

BVM(3) is readily available from Rubicon http://archive.rubicon-foundation.or...123456789/2258

Thanks!

[Jax]

BVM(3) is readily available from Rubicon http://archive.rubicon-foundation.or...123456789/2258

Sigh. Now I really don't get it. The BVM(3) discussion in the attached study (at above) concluded



Why would they use a"conceptually incomplete and can be considered only as a mathematical descriptor --" model to test incidences of DCS in a later study?

[PfcAJ]

None of the algorithms are conceptually complete.

They're literally all wrong. How wrong is what this debate is about.

[Nix]

The human body is a very complex system and the etiology of DCS is not fully understood. From what I have read of the literature I don't think it is currently possible to create a model that is conceptually complete. The statement you are quoting is just pointing out that while the model does a good job of predicting the likelihood of DCS within its training set it is not modelling all the physiology of the body. It is using an approximation based upon 3 compartments each with a single bubble.