Deep stops in your Suunto ?

[boulderjohn]

I'm beginning to see a few responses relating to the trustworthiness of decompression science (DS). Phrases like "not an exact science", "voodoo science", "not tested enough", "it's [ONLY] a theory", etc. are outright wrong or misleading at best. A theory is not a best guess as some layman are led to believe. A theory is a scientific framework in which facts and hypothesis are postulated. Bubbles beyond a minimum size and number lead to DCS. This is a fact and is not debated.

Actually, I think this is all open to more debate than you suggest here. There have been some raging arguments about deep stops lately, both for decompression diving and for no-stop recreational diving. The quotations you were opposing were related to recreational deep stops, and I think they are pretty accurate. As I said earlier in this thread, "This 2011 article by DAN's Dr. Peter Bennett supports the idea of using Deep Stops on recreational dives. This 2010 article published by DAN is less supportive of the idea of deep stops for recreational divers. Dr. Bennett was one of 5 experts in a panel discussion in that article, and he had the most favorable opinion, with some other of the experts opposed to it." It is definitely not settled science.

I have studied Decompression Sickness and theories about its causes and its prevention more than most, and as a technical diving instructor, I am expected to teach it to a much greater degree than you find in most courses. I have struggled through a lot of competing theories. Right now, after reading a lot of what is being written these says, I am less convinced that I know what is going on than I was only a month ago. I guess I am working my way closer to being an expert in Richard Pyle's definition:

In a famous explanation that I cannot find right now, Dr. Pyle said that if you ask a random person on the street what causes DCS, that person will say, "I don[t know." He then goes through an ascending level of expertise, summarizing the different answers you will get by different people with different levels of knowledge. When you finally get to the truly elite experts, the small handful that have really, truly studied it, they will say, "I don[t know." It turns out that the uninformed random man in the street had the best answer after all.​

 

[Remy B.]

If you don't understand the thinking behind doing a deep stop... I suggest you don't use that feature.

PS - how will you be more safe with two computers?

---------- Post added December 29th, 2014 at 05:41 PM ----------

.

so diving without a DC is more safe ???, so much for the backup theory/practice, we got all that wrong I guess, yes you can abort a dive if your DC die, at list I will keep diving since I have a backup, and can go confident in to the next dive, don't need to rent another one at list

 

[EFX]

The quotations you were opposing were related to recreational deep stops.....

While the quotes I took issue to were posited in this thread which do happen to live in a limited context, I was commenting on the perceptions some readers may have regarding the science in general which exists outside of any limited well defined contexts. Take for instance the phrase "exact science". If the science isn't exact why not substitute are own thoughts (misconceptions). Instead of "exact science" how about "science based on inexact conditions". While some may see this as nitpicking I see it as more descriptive. After reading some reviews here on SB I bought Lewis's book "The six esentials skills for technical divers". While extoling some great ideas and practical knowlege I was dissapointed in his use of certain phrases, one of them being "voodoo science". Voodoo science? Really? Voodoo doesn't even go with science. One is about magic. The other is based on emprical testing. What came across initially was we can't have much faith in the algorithms. Of course, after picking up the book from across the room I realized he was just being cute and entertaining (as already demonstrated by other no less than entertaining but cute phrases). Your quote fromn the elite experts "We don't know", is a good example. It is out of context and misleading.

---------- Post added December 29th, 2014 at 05:34 PM ----------

If you don't understand the thinking behind doing a deep stop... I suggest you don't use that feature.
PS - how will you be more safe with two computers?

so diving without a DC is more safe ???, so much for the backup theory/practice, we got all that wrong I guess, yes I guess you can abort a dive if your DC die, at list I will keep diving since I have a backup, and can go confident in to the next dive, don't need to rent another one at list

I think you misunderstood RJP. I think he was saying that if you don't understand the feature on one computer, having another computer with the same feature will not make you understand the feature any better, and will therefore not make you any safer. RJP can correct or pass.

 

[boulderjohn]

While the quotes I took issue to were posited in this thread which do happen to live in a limited context, I was commenting on the perceptions some readers may have regarding the science in general which exists outside of any limited well defined contexts. Take for instance the phrase "exact science". If the science isn't exact why not substitute are own thoughts (misconceptions). Instead of "exact science" how about "science based on inexact conditions".

I don't quite understand what you are saying. Our knowledge of issues related to scientific inquiry runs through the entire spectrum from "We're got this mailed down nice and solid" to "Hmm. I wonder what's going on." It's not just two camps: 1) Absolute fact and 2) wild guess. In terms of decompression, we have some pretty good ideas on what causes it, and we know that some ascent profiles work better than others. We still have quite a ways to go in our understanding, and some of the really popular procedures followed today may some day be seen as primitive and uninformed.

 

[EFX]

Yes, I agree with you. I think you missed my point. I will paraphrase the original context that led to my responses. Two posters implied that since DS is not an exact science we can therefore substitute deep stops where none are called for or, if we do them they're inconsequential for rec NDL dives. I don't think this is a safe practice despite the experience some have had.

 

[Remy B.]

While the quotes I took issue to were posited in this thread which do happen to live in a limited context, I was commenting on the perceptions some readers may have regarding the science in general which exists outside of any limited well defined contexts. Take for instance the phrase "exact science". If the science isn't exact why not substitute are own thoughts (misconceptions). Instead of "exact science" how about "science based on inexact conditions". While some may see this as nitpicking I see it as more descriptive. After reading some reviews here on SB I bought Lewis's book "The six esentials skills for technical divers". While extoling some great ideas and practical knowlege I was dissapointed in his use of certain phrases, one of them being "voodoo science". Voodoo science? Really? Voodoo doesn't even go with science. One is about magic. The other is based on emprical testing. What came across initially was we can't have much faith in the algorithms. Of course, after picking up the book from across the room I realized he was just being cute and entertaining (as already demonstrated by other no less than exact but cute phrases).

---------- Post added December 29th, 2014 at 05:34 PM ----------





I think you misunderstood RJP. I think he was saying that if you don't understand the feature on one computer, having another computer with the same feature will not make you understand the feature any better, and will therefore not make you any safer. RJP can correct or pass.

I believe it will not make me unsafer or hurt me, my dives are multilevel dives, so not diving with a backup DC actually I will consider it a little unsafe, I may plan to a max depth before I dive, but if I see something interesting 5m below my planned dive I will go after it, taken I have enough air

To me there are to many variables in a dive that can change I assure you I don't know what happen inside the magic box, but I trust the magic box, since a lot of smart man hours and money went in to the R&D, if it really was worthless then it will not be in the DC, I have two magic boxes now, one that does deep stops by it self an another that I can choose to activated or not, since one have it I may as well make both as similar as possible even if they use different deco NDL models or safety margins apparently.

I have not tested the Suunto yet so I will see how it behave, if it activate every time I pass 18m then I will turned off, since in my wrong believe it has to do more with the time of exposure at determined depth.

I only had my Mares give me a 2 min deep stop, and that happen because I spent some time below 27m in a wreck, I have been deeper without that safety deep stop = not enough time at depth to trigger the deep stop, in the end I respect my 5m safety stops, and I add a little more time at that depth beyond what the DC tell me, since I know it will not hurt to do so and keep on diving and looking at marine live

 

[boulderjohn]

Yes, I agree with you. I think you missed my point. I will paraphrase the original context that led to my responses. Two posters implied that since DS is not an exact science we can therefore substitute deep stops where none are called for or, if we do them they're inconsequential for rec NDL dives. I don't think this is a safe practice despite the experience some have had.

I believe that in the specific case being discussed you may have missed their points. As I read their arguments, they were stating accurately that the evidence for or against deep stops in recreational diving is not good enough to make a solid decision. There are people who believe in them; there are people who don't. You are probably safe following an established deep stop algorithm, and you are probably safe following an algorithm that does not use deep stops. You should, however, follow an established algorithm and not make something up on your own.

 

[RJP]

so diving without a DC is more safe ???, so much for the backup theory/practice, we got all that wrong I guess,

A.) People dive safely without computers all the time; not too long ago... EVERYONE did.
B.) Having a backup computer doesn't make you "more safe"*

* with a special note to the guy that I met several years ago who had two computers. One for the first dive... and one for the second dive. "There's something wrong with this one... it always beeps on the second dive."

Having a back-up for convenience and to prevent trip interruption makes some sense... but that's different than being "more safe."

---------- Post added December 29th, 2014 at 08:44 PM ----------

I think you misunderstood RJP. I think he was saying that if you don't understand the feature on one computer, having another computer with the same feature will not make you understand the feature any better, and will therefore not make you any safer. RJP can correct or pass.

Nope. Was just stating the fact that diving with two computers won't make a diver more safe... irrespective of feature set.

 

[Remy B.]

humans are more prone to make miscalculations, mistakes than a machine, yes I will agree with you it doesn't make you more safe because you still can choose to ignore all bells and alarms, readings, warnings etc, etc, does it make me FEEL safe, hell yeah, and more relax that I don't have to make calculations and will gain more dive time in a relax matter, can I jump in the water with a watch and a depth gauge and memorize the planned dive table and do a square dive, yes,

but me been a rucky if something go wrong and spend more time than planned It will take a lot of more time to recalculate and may get it wrong, so a DC is more safe for me and I believe for anybody that follows what the DC is warning you about during a dive, but that is my personal opinion.

 

[RJP]

but me been a rucky if something go wrong and spend more time than planned It will take a lot of more time to recalculate and may get it wrong, so a DC is more safe for me and I believe for anybody that follows what the DC is warning you about during a dive, but that is my personal opinion.

I think you're confusing having one computer being "safe" with having two computers being "more safe."