DIR- GUE GUE standard for gradient factors?

[boulderjohn]

Gradient Factors in a Post-Deep Stops World

Interesting article from GUE

In big bold letters in the middle of the GUE article it says:

"The emerging body of evidence against deep stops suggest common gradient factor setting should be modified to de-emphasize deep stops."

"However, since about 2005, evidence has been accumulating from comparative decompression trials that shows deep stops are not more efficient, and possibly less efficient, than shallow stops."

Although this article was published in the GUE Blog, it is a little confusing to use the phrase "from GUE," because it implies an endorsement. Not long after publishing that, they published this: Digging Deeper: A Fresh Case for Deep Stops

The title promises a "fresh case for deep stops" in decompression diving, the precise opposite of the Doolette position. The article then describes the untested and unpublished opinions of some researchers and references old studies on no-stop diving.

 

[JonG1]

I think this is the relevant work from Mark P, in so far as her references the findings from the study at NDAC.

In essence the 2 profiles resulted in lower bubble scores on the deep stops profile immediately on surfacing but slower reduction over time, and higher scores at surfacing on the shallow stops but decreasing quicker over time IIRC.

 

[boulderjohn]

I think this is the relevant work from Mark P, in so far as her references the findings from the study at NDAC.

In essence the 2 profiles resulted in lower bubble scores on the deep stops profile immediately on surfacing but slower reduction over time, and higher scores at surfacing on the shallow stops but decreasing quicker over time IIRC.

Nice presentation. If you want to skip the early theory parts and get to the conclusions, they start at about the one hour mark. As I understand current thinking among the majority of theorists, his conclusions are pretty much in line with them.

 

[Trace Malinowski]

Should ask Trace Malin how ratio deco went for him

I know this thread is old, but I happened to see this post when I Googled "gradient factors" tonight. To set the record straight, I developed DCS on my second dive after following the science and eliminating deep stops. I had successfully used ratio deco for a decade of Nitrox and Trimix diving. I took the hit after switching to using a Shearwater and moving the GF Low from 30 to 50.

 

[Nick_Radov]

In North Carolina dive boats, everybody sleeps on the way back. Almost Everybody! Why is that? Are we as a nation so accustomed to napping at 2:00 in the afternoon that moment the dive on U-352 is over, everyone falls asleep? Would the same people be sleeping at the same time if they were at home running around in the backyard or chasing their dog? Why don't the same people take these 2:00 pm naps after Florida dive charters to that shallow reef? They swim and exert so much more on Florida trips as compared to the NC trips because bottom times in shallow dives are longer then why do they all sleep on the latter and not the former?

I have no real evidence for this but I suspect that post-dive fatigue often has more to do with mild hypothermia than with decompression stress. Sometimes I need a nap after a long open-water surface swim workout.

 

[cathal]

I know this thread is old, but I happened to see this post when I Googled "gradient factors" tonight. To set the record straight, I developed DCS on my second dive after following the science and eliminating deep stops. I had successfully used ratio deco for a decade of Nitrox and Trimix diving. I took the hit after switching to using a Shearwater and moving the GF Low from 30 to 50.

Correlation v causation can be two different things

 

[Trace Malinowski]

Correlation v causation can be two different things

I know that. In light of the pandemic, I found it amusing that I followed the science away from deep stops and happened to take a hit on my second dive. The point of my post was simply to say that I wasn't using ratio deco on the dive that bent me. There were several factors that contributed to the hit. I've returned to diving and teaching.

 

[rjack321]

I know this thread is old, but I happened to see this post when I Googled "gradient factors" tonight. To set the record straight, I developed DCS on my second dive after following the science and eliminating deep stops. I had successfully used ratio deco for a decade of Nitrox and Trimix diving. I took the hit after switching to using a Shearwater and moving the GF Low from 30 to 50.

RD bent me a couple times before I adjusted the deep stop portion and extended the shallow time. Obviously mileage may vary