Shearwater coming out with new DC?

[uncfnp]

The dive log does continue to count from the manual change in the dive count .. . ??? :huh:

---------- Post added January 1st, 2016 at 01:43 PM ----------

I tried it for the first time this last trip. Apparently it's just me. Not sure what I could be doing wrong but I would have to go in and manually change each successive dive to match my log.

 

[Jax]

From http://archive.rubicon-foundation.org/xmlui/bitstream/handle/123456789/10269/NEDU_TR_2011-06.pdf

Following 170 fsw for 30-minute bottom time air dives, alternative distributions of 174 minutes TST were created by all possible combination of five-minute blocks of time at 100 and 90 fsw, 10-minute blocks of time from 80 to 20 fsw, and the remainder of the 174 TST at 10 fsw

Five minute blocks of time at 90 and 100? Does not seem right!

Multi-deco has 1st stops at 80 & 70 at 3 min each, VPM-B + GFS. ???

---------- Post added January 1st, 2016 at 02:01 PM ----------

I tried it for the first time this last trip. Apparently it's just me. Not sure what I could be doing wrong but I would have to go in and manually change each successive dive to match my log.

Are you changing it on the Petrel, or in the Shearwater Desktop?

You need to change the dive log number to the *last* dive number you had, and change it in the Petrel.

 

[Jax]

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Page 49 of the manual at https://d2uy6nbe9j4vef.cloudfront.net/wp-content/uploads/2012/08/PetrelManual_DocRevD.pdf

 

[KenGordon]

From http://archive.rubicon-foundation.org/xmlui/bitstream/handle/123456789/10269/NEDU_TR_2011-06.pdf



Five minute blocks of time at 90 and 100? Does not seem right!

Multi-deco has 1st stops at 80 & 70 at 3 min each, VPM-B + GFS. ???
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I recommend you read the all the deeps stops threads which discuss this study. Either start with the rebreather world one (a big job) or read the more recent helium gas kinetic one on SB and follow the links to the useful posts in previous ones.

 

[Jax]

I recommend you read the all the deeps stops threads which discuss this study. Either start with the rebreather world one (a big job) or read the more recent helium gas kinetic one on SB and follow the links to the useful posts in previous ones.

That's a thought, thank you, but there is a lot there that just doesn't apply.

The divers were mostly 40 and below, fit, and almost none had body fat greater than 20%.

 

[uncfnp]

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Page 49 of the manual at https://d2uy6nbe9j4vef.cloudfront.net/wp-content/uploads/2012/08/PetrelManual_DocRevD.pdf

View attachment 221889

Thanks. I changed it in the Petrel but I don't recall the screen looking like that. I think it was on the third page of each specific dive. Guess that is why it did transfer to future dives.

Guess that puts the Petrel one step closer to perfection!

 

[KenGordon]

That's a thought, thank you, but there is a lot there that just doesn't apply.

The divers were mostly 40 and below, fit, and almost none had body fat greater than 20%.

Isn't that true of all human subjects in deco research? The goats were even younger.

 

[scubadada]

Redistribution of decompression stop time from shallow to deep stops increases incidence of decompression sickness in air decompression dives

This compares two profiles. They get the divers out of the water at the same time. One bends three, one bends ten (in 175 ish) If only time/speed counted they would be equally conservative. If you were getting nearly bent on the shallow one (as per the 'listen to your body' school) and changed to the deep one (which has a more 'conservative' first gf number) by the results of this study you would increase the chances of getting bent.

It is all quite complicated and non obvious. Hence being able to choose from any old pair of numbers may lead to unexpected outcomes. Not really for the casual user.

I said nothing about hard science proving how not to get bent, however there absolutely IS hard science proving that "slow," and "conservative" are NOT the same thing. Likewise, "fast" and "liberal, or aggressive," are not the same thing. Scubadada seems to want people to believe that we're simply using different words to describe the same thing. That is wrong. As in, not correct. People seem to think that simply because they have an opinion, it is valid. That is not the case. Scubadada's opinion that we are communicating the same concepts by equating slow and conservative, or fast and liberal/aggressive, is not correct.

KenGordon's article proves it, I could repost it, but what's the point? You either understand that calling something "slow" is not the same thing as calling something "conservative," and calling something "fast" is not the same as "liberal" or "aggressive," or you are wrong.

Despite numerous attempts to make sure all knew my dive profile was basically recreational, other posters have not been able to abandon the tech mindset.

---------- Post added January 2nd, 2016 at 11:51 AM ----------

If a child of yours bought a GF based computer, how would you suggest they choose the settings?

What does a child have to do with it? Shearwater is marketing to the recreational diver with the recreational mode. If you choose the rec mode, I guess you choose between the default 40/85 or one of the other standard combos, 45/95 or 30/75, right? Is this better than going into tech mode and choosing your GFs with enough knowledge to make a decision? I have a strong suspicion that 45/95 is not far off from the DSAT algorithm I've been diving for more than 1000 dives. I don't recall anyone arguing that the DSAT algorithm is not safe for recreational diving. I think it is actually conservative for deco diving.

 

[JohnnyC]

Despite numerous attempts to make sure all knew my dive profile was basically recreational, other posters have not been able to abandon the tech mindset.

Despite numerous attempts to obfuscate the issue, you are still incorrect. People get bent doing recreational, "non-decompression" dives as well. Slow does not equal conservative. Fast does not equal aggressive. It's as simple as that. But keep pretending that it's just a communication thing....

I can explain it to you, but I can't understand it for you.

 

[Nuribromanski]

Always got to think of those fearless fools

no u dont