Data...

[sharkmasterbc]

Does anyone know of any tests being done (imperical data) about reverse profiling ?

I had a DM tell me it was OK, as long as I had a good SI ?
We ended up just doing our own thing (as he stayed on the boat) and didn't do a reverse profile.

 

[Dr Deco]

Dear Scuba Board Readers:

The workshop by the Smithsonian Institution has considerable data from open water diving. I am not aware of any laboratory tests.

As long as one remains within the parameters (deeper not more than 40 fsw under the shallower) , experience shows reverse profiles are OK.

Dr Deco :doctor:

Please note the next class in Decompression Physiology :book3:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[rcohn]

Dear Scuba Board Readers:

The workshop by the Smithsonian Institution has considerable data from open water diving. I am not aware of any laboratory tests.

Dr Deco :doctor:

Please note the next class in Decompression Physiology :book3:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

Didn't you do testing of reverse profiles yourself? I seem to recall the tests of the RDP included a reverse profile. I believe Navy testing did as well. I'll check my copy of the conference proceedings tonight.

Ralph

 

[ArcticDiver]

Believe there was a DAN Conference on the subject about 3, or so, years ago. I remember reading the Proceedings but can't remember exactly the participants.

The Big Message from the Proceedings I recall is that the original idea of deeper dive first came primarily from equipment limitations.

Dive tables didn't handle the reverse profiles very well. Along came better data sampling and table application in the form of dive computers. Then the old equipment limitation was overcome.

Dives where the deeper dive is second make a lot of sense in a variety of circumstances. One that comes immediately to mind is when visiting a new dive site. It makes sense to approach cautiously both in terms of terrain and in terms of depth. Something, like a test pilot who nibbles a bit more at the new airplane's performance envelope on each flight. Until finally the whole thing is explored.

 

[MonkSeal]

AFAIK RGBM adresses reverse profiles. BRW can probably give some info about this issue.

 

[Dr Deco]

Hi rcohn:

We did a few "reverse profiles" during a small pretest series (to shake down the procedures and equipment.) At that time it was decided not to include these profiles in the full test series since thaey were not recommended by the training agaencies in 1985.

 

[Saturation]

There is a discussion between Dr. D, BRW and myself on RP. It is not supported as a preferred diving strategy based on bubble theory, RGBM or VPM .. and I recall BRW was at the conference and spoke against it.

In general, BRW suggests the difference between RP depths is not more than 30' in dives shallower than 100'. In dives past 100', BRW suggests the difference can be as high as 70'.

http://scubaboard.com/showpost.php?p=298680&postcount=7

http://scubaboard.com/showpost.php?p=417738&postcount=25

http://scubaboard.com/showpost.php?p=298020&postcount=1

There are slight differences between what is recommended on those links but the magic number of 30-40' is roughly 1 ATA difference up to 100-130' then 2 ATA difference on dives past 130' [66' what BRW states as 70'].