New NAUI Standards for Deep Stops & Safety Stops

[ronbeau]

I wonder if manufacturers are going to modify their dive computer firmware to reflect the changes?
Does anyone know if PADI, SSI, YMCA etc have adopted the same changes?

NAUI has instituted new deep stop and safety stop recommendations. The actual text from the NAUI HQ Report appears below:

Rule of Halves Revised

Based upon the most current research and
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analysis of decompression science on the
value of deep stops in “no-required-decompression”​

diving by Bennett et al (Undersea and Hyperbaric
Medicine 2007 ; 34(6): 399-406,


the NAUI Board of Directors

approved a change to the NAUI Standards​

and Policies on March 7, 2008, at its annual
meeting. A reprint of the study is included
in this issue of ​

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Sources (pp. 48 ff).​

The membership is advised to make a pen

and ink change in their personal copy of

the manual and mark both the title page
and changed page with “​

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rev. 1-08.” Notice​

of these changes is included in existing

inventory of the NAUI Standards and

Policies Manual, and the changes will be​

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incorporated in the next printing.

S&P Page 2.16 – Current wording​

It is recommended that following dives in

excess of 40 feet (12m), divers make a ​

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one minute stop at a depth that is half that
of the deepest depth reached during the dive

and make a precautionary stop in the​

10-20 feet (3-6m) zone ​

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for three to

five minutes before returning to the surface.​

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The precautionary stop time may be

considered “neutral” time- not counted as

either dive time or surface interval time.​

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S&P Page 2.16 – Changed wording​

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It is recommended that following dives in

excess of 40 feet (12m), divers make ​

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a two to three minute stop (with two and
one-half minutes being optimum) at a

depth that is half that of the deepest depth​

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reached during the dive and make a

precautionary stop in the 10-20 feet (3-6m)

zone ​

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for one minute before returning to​

the surface. The precautionary stop time

may be considered “neutral” time- not

counted as either dive time or surface
interval time.​

Bennett et al have extended their study
to include diving over a greater range of
depths from deep (130 fsw) to shallow and
will present these findings at the UHMS
“Decompression and Deep Stop Workshop”
on June 24-25, 2008, in Salt Lake City,
Utah, sponsored by NAUI Worldwide and​

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other dive industry members.


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[fisherdvm]

Hmmm, I find it interesting that they are trimming the shallow 15/20 ft safety stop from 3 to 5 minutes to simply 1 minutes.

I always thought that the shallow safety stops were more important than the deep stop.

Explain to me please.

 

[ucfdiver]

Hmmm, I find it interesting that they are trimming the shallow 15/20 ft safety stop from 3 to 5 minutes to simply 1 minutes.

I always thought that the shallow safety stops were more important than the deep stop.

Explain to me please.

The First Stop / The Deep Stops | Global Underwater Explorers

In determining where to start your decompression, the logic is very simple: you want to let gas escape from the tissues prior to bubbling.

Min Deco Table-
http://dir-diver.com/en/knowledge/min_deco_table.html

Not a cool aide drinker myself, but they do seem to have the best material on this topic for a diver like me who hasn't made it to a tech class yet.

 

[fisherdvm]

Still doesn't explain why they trimmed the 20 ft safety stop from 3 to 5 minutes to simply 1 minute.

Perhaps it is to make the sum of the minutes at the deep stop and the shallow stop to be equal to about 5 or 6 minutes total.

This would seem to require twice the gas as the usual safety stops, which one would have to factor in when planning the terminate the dive.

But I wonder, if you are down to 400 psi, and had to do only one safety stop, I wonder if your gas would be best spent at 10 ft, instead of half of the max depth??

 

[ClayJar]

The full presentation (among many others) will be at the UHMS "Decompression and Deep Stop Workshop" on June 24-25, 2008, in Salt Lake City. Musing about it now would be counterproductive, although there's lots to read in Rubicon.

(As for your example, if you're out of air completely, I would skip the deep stop *and* the safety stop, but that's rather immaterial.)

 

[ronbeau]

Still doesn't explain why they trimmed the 20 ft safety stop from 3 to 5 minutes to simply 1 minute.

Perhaps it is to make the sum of the minutes at the deep stop and the shallow stop to be equal to about 5 or 6 minutes total.

This would seem to require twice the gas as the usual safety stops, which one would have to factor in when planning the terminate the dive.

But I wonder, if you are down to 400 psi, and had to do only one safety stop, I wonder if your gas would be best spent at 10 ft, instead of half of the max depth??

Maybe Cerich can comment on this since he is a NAUI course director.
It looks like the UHMS study is going to be presented this coming week.

 

[gnwes]

Still doesn't explain why they trimmed the 20 ft safety stop from 3 to 5 minutes to simply 1 minute.

Perhaps it is to make the sum of the minutes at the deep stop and the shallow stop to be equal to about 5 or 6 minutes total.

This would seem to require twice the gas as the usual safety stops, which one would have to factor in when planning the terminate the dive.

But I wonder, if you are down to 400 psi, and had to do only one safety stop, I wonder if your gas would be best spent at 10 ft, instead of half of the max depth??

Does it really matter why they changed a 'recommendation'? For what its worth, one could NOT do a safety stop, period and be fine at the end of the day.

 

[gnwes]

wth? double post

 

[RonFrank]

In rec diving, one SHOULD be able to skip all stops, and be FINE at the end of the dive assuming that the ascent rate is within the limits.

I don't do that personally, but it should be possible.

Not sure why the guidelines were changed. Seems like they maybe bored! I applaud a deep stop, but I also do a shallow stop, and honestly I do not know of anyone that does not do a SS stop in the 15~20 range even if it's just continuing to cruise the landscape at that depth for a bit.

SS's are a good time to do skills. I often shoot a Sausage from about 35' feet while at the Hole. It's not as easy as it looks, and it is a good skill to have at hand.

 

[MXGratefulDiver]

There's really too much going on in your body to explain it simply (which is why nobody ever does) ... but a really rough summary would be as follows ...

- The shallow stop most benefits tissues that offgas more slowly
- The deep stop most benefits tissues that offgas more quickly

- Slow tissues are more likely to be the source of a Type I hit (muscles, joints, skin)
- Fast tissues are more likely to be the source of a more serious Type II hit (nervous, pulmonary, or circulatory)

In my NAUI tech classes, the rule of thumb is that if you MUST shave time off your deco schedule, shave it from the shallow stops rather than the deep stops. Type I hits are more easily treatable.

Apparently this line of thinking is making its way into the recreational world as well ...

... Bob (Grateful Diver)