Reverse Profiles, DAN, Computers

[BRW]

All,

Just want to correct a few statements on some recent
posts on reverse profiles:

1) the RP Wkshp was sponsored by the Smithsonian
Institute, NOT DAN.

2) SI Wkshp ONLY suggested RPs were OK for
recreational air diving with deltas less than 30 fsw,
and depths less than 130 fsw. This is always misquoted.

3) Data from tech community suggest DCI IS enhanced for
RPs with deltas GREATER than 40 fsw (see SI Wkshp
Proceedings, TDID, etc). At LANL, we saw 16% DCI hit rate
on repetitive deco dives on various gas mixtures with
deltas beyond 40 fsw. Diver beware -- and this holds
for recreational air folks too.

4) Dive computers with RGBM DO account for the above RP
data, and treat repets accordingly (Suunto, Mares, Dacor,
Hydrospace, Plexus, and soon Zeagle). But these are
the only ones.

5) released RGBM Tables (NAUI) for recreational and
technical air, nitrox, heliox, trimix, and helitrox (with
deco mix switches) do NOT admit RPs from the
point of view of all of the above, plus optimization
of bottom times related to dissolved gas kinetics.

Cheers to all,

Bruce Wienke
Program Manager Computational Physics
C&C Dive Team Ldr

 

[Saturation]

BRW once bubbled...
All,

Just want to correct a few statements on some recents
posts on reverse profiles:

1) the RP Wkshp was sponsored by the Smithsonian
Institute, NOT DAN.

2) SI Wkshp ONLY suggested RPs were OK for
recreational air diving with deltas less than 30 fsw,
and depths less than 130 fsw. This is always misquoted.

3) Data from tech community suggest DCI IS enhanced for
RPs with deltas GREATER than 40 fsw (see SI Wkshp
Proceedings, TDID, etc). At LANL, we saw 16% DCI hit rate
on repetitive deco dives on various gas mixtures with
deltas beyond 40 fsw. Diver beware -- and this holds
for recreational air folks too.

4) Dive computers with RGBM DO account for the above RP
data, and treat repets accordingly (Suunto, Mares, Dacor,
Hydrospace, Plexus, and soon Zeagle). But these are
the only ones.

5) released RGBM Tables (NAUI) for recreational and
technical air, nitrox, heliox, trimix, and helitrox (with
deco mix switches) do NOT admit RPs from the
point of view of all of the above, plus optimization
of bottom times related to dissolved gas kinetics.

Cheers to all,

Bruce Wienke
Program Manager Computational Physics
C&C Dive Team Ldr

Many thanks for BRW's direct input for correction and clarification.

I've made changes to my post to acknowledge the Smithsonian led gathering and further notes of the meeting are still summarized here:

http://www.undercurrent.org/UCnow/articles/DeepDive200005.shtml

Its probably most critical to reinforce that "delta", difference between the RP dives, is best under 40'.

Since differences between tissue gas tensions, breathing gases, and overall pressures on technical divers versus air NSL dives are substantial, I'm not sure one can put technical and NSL dives in the same category. For a 40' delta between two RP dives within the 132' limits of NSL diving, its likely many dives would meet this requirement. But with practical limits of 300' for technical diving [otherwise there are no strictly no limits], the likelihood of exceeding 40' is quite high.

In recreational dives as recreational drives, there is a difference in the risk of injury while not wearing a seatbelt and not having any breaks. It also depends on the speed of travel and the type of driven automobile. RP is not good practice and should be viewed as something to avoid, but it is likely not as critical as holding one's breath during ascent.

Thus, whether RP dives substantially increase DCI rates among recreational divers on air, I frankly cannot say beyond the workshops conclusion and leave commentary on RP decompression dives to Dr. Wienke's data.

 

[leadweight]

BRW once bubbled...



4) Dive computers with RGBM DO account for the above RP
data, and treat repets accordingly (Suunto, Mares, Dacor,
Hydrospace, Plexus, and soon Zeagle). But these are
the only ones.

Bruce,

I am a bit confused as to the status of the Mares and Dacor computers. I don't see the term RGBM anywhere in the M1 manual. Meanwhile Mares has this RGBM website, but makes no mention of a specific product. Are you talking about present or future products from Mares/Dacor? Also, is Plexus still a development stage item?

 

[BRW]

Suunto, Hydrospace have released products.

Mares kicked off RGBM M1 in Verona in March

Plexus is close to a release

Dacor is "working" according to HTL/Head/Mares

Zeagle is in negotiation stages for full RGBM

ABYSS has released software

GAP will release RGBM software on July 1.

Thanks for the inquiry.

Regards to all.