DAN Y-40 Test on Deep Stops. Lower bubble count?

[Jack Hammer]

I think when looking at studies it is important to note that scientists do not always use the same definitions as the general public. i.e., the usage of descriptors like "deep", "shallow", "bounce", can mean something totally different from how we, as divers, use them.

 

[Macan]

@jlcnuke - Could you please point out where did Dr. Mitchell wrote that? I’m interested to locate it so I can absorb the context and circulate it (full attribution to Dr. Mitchell) amongst folks here in Saudi Arabia who just posted the Dr Marroni video.

It’s in the comment section of the YT video, Dr. Mitchell was responding to one of the comments. I missed that too.

The video excerpt of the Y-40 study only presented the stops for both shallow and deep profiles. The video didn’t indicate the GF used, and the casual viewer may read the results to mean that “Deep” stops are better (ie lower bubble count).

But after knowing that the Deep Stop profile in the study was using GF lo of 50 and the Shallow Stop group was using GF lo of 100, it becomes clear that something is not right. Dr. Mitchell’s response cleared things up. I agree with him.

Rjack321 said it best:

GF low of 50 is not "deep"
GF high of 100 is nuts

 

[jlcnuke]

@jlcnuke - Could you please point out where did Dr. Mitchell wrote that? I’m interested to locate it so I can absorb the context and circulate it (full attribution to Dr. Mitchell) amongst folks here in Saudi Arabia who just posted the Dr Marroni video.

As @Macan said, it's in the comments. It's a reply to DroPsyDro's comment that mentioned him.

 

[jlcnuke]

30 low is on the deeper side but unless you are doing 60+mins moving up to 50 low is all within the margin of error anyway.

3 or 5 more mins at intermediate stops is inconsequential in the grand scheme of things. 3 hrs of deco total with 25mins shifted "deeper" is categorically a different kind of dive than 25mins total of AN/DP level deco. For many tech1 or AN/DP level dives (150ft for 25mins) the first stop isnt even at the 70ft EAN50 switch yet no matter what GF low you choose.

Yeah, I'm only AN/DP right now, so my deco dives are hitting the first stop at 40-50' most of the time right now.