Why do people add a few minutes to their last deco stop?

[boulderjohn]

Yes. It was measure of VGE, but the time chosen for the stop was arbitrary as best I can tell, and both of them showed a reduction in VGE, but is 5 minutes better than 3, is 10 better than 5? is 20ft better than 15? Those parameters were not tested.

That, in general, is the problem with testing NDL ascent profiles--too many options. The studies that claimed a benefit to deep stops on NDL dives suffered from the same problem--you added to the ascent time and found an improvement, but you did not show that the depth at which it was added was beneficial. Is it possible that adding that time to the shallow stop would have had an even greater benefit?

 

[boulderjohn]

The one study that I keep coming back to personally is the one that showed that saturation divers on air at less than 20 feet could safely ascend directly to the surface--all saturated tissues were within M-values. To me that is pretty simple. If I am above 20 feet, any tissues that are above m-values will eventually drop to a safe level, and the tissues that are still on-gassing cannot go too far.

For me, that means the traditional safety stop depth makes sense. I cannot possibly stay too long, and staying a little longer might help in some cases.

 

[JMarc]

The one study that I keep coming back to personally is the one that showed that saturation divers on air at less than 20 feet could safely ascend directly to the surface--all saturated tissues were within M-values.

Do you have a more complete reference for this one? I'm interested in reading it.

Thanks

 

[boulderjohn]

It was cited in a recent SB thread--perhaps the one @tursiops recently linked. I am in a motel in the middle of a multi-day trip and about to hit the road.

 

[dmaziuk]

The one study that I keep coming back to personally is the one that showed that saturation divers on air at less than 20 feet could safely ascend directly to the surface--all saturated tissues were within M-values. To me that is pretty simple. If I am above 20 feet, any tissues that are above m-values will eventually drop to a safe level, and the tissues that are still on-gassing cannot go too far.

Note, however, that M-values is where the model's statistical likelyhood of clinical DCS is encoded. I.e. saturation dives to/above no-limit depth are only as "safe" as the model's target incidence of DCS.

 

[BRT]

I disagree. Having a healthy fear of something that you like doing is good, doesn't mean you should stop. I see it in my kids. One is fearless, and he'll push the envelope. I have another that is way more cautious, has some fear, and knows his limitations. Which one do you think is more likely to get hurt?

What's that saying, there are old divers and there are bold divers, but there are no old bold divers.

Pretty much all divers are old divers.

 

[TrimixToo]

Pretty much all divers are old divers.

Hey! I resemble that remark!