Two safety stops?

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billt4sf

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Location
Vincennes, France near Paris
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A recent article in Dec 2012 Dive Training mag talks about DCS and safety stops. Essentially, it says that there is good evidence (reduction or elimination of silent bubbles in the spinal cord) that if you're going to 80 ft or more, it's probably a good idea to make two safety stops: one at half your max depth for 2 - 3 minutes and then another one at 10 - 20 ft for 4 - 5 minutes. It makes logical sense that it would be more important to do these on a multi-day dive vacation.

I know there are alot of folks that have dived for decades without doing two stops that will no doubt claim it's unnecessary; and obviously few that have dived for a long time that have had the bends. So I'm not sure what my question is, but anyway I thought it was interesting.

Mostly I wonder if I can organize my dives enough to do these stops even if I wanted to -- I am most certainly an air hog, and hovering at (say) 40 ft is probably going to be in open water. With 50 dives under our belt I'm sure we could pull that off, at least in warm water.

The article is a good one, I thought, and is supposed to appear in Dr. Alex Briske's book "The Complete Diver".

- Bill
 
Uwatec galileo sol computer has used this feature calling it PDIS, profile dependent intermediary stop. I try to use it on every dive I do, probably 90% of the time. I like the safety margin.


Michael

Sent from my Nexus 7 using Tapatalk HD
 
It's not new at all ....I was doing it in the 70's .. But that was when your last stop was called a Deco stop and not a " safety stop "....

Jim...
 
When I was diving in Key West a couple months ago on the "most popular" wreck there (It's like 140 ft on the bottom and you can observe high portions of it from much less deep) the Captian of the dive boat told us to do a stop at 65 ft for 5 minutes and then the normal 15 ft for three minutes. Note that he specifically mentioned this was for a NO DECO dive and everything should be within recreational limits. Sounds like some places like you to add more safety margin into your deeper dives.
 
There was a DAN study that looked at ascent rates and stops about 10 years ago. That study also supported the idea of a deeper stop as well as the traditional stop.

Yes, it is true that stops were not done much decades ago. Research in the past 10-15 years suggests they are more important than used to be thought. That's how things change. We don't use iron lungs for polio victims anymore, either. I am an educator by profession, and I spent many years with the job of teaching teachers to adapt instructional strategies to what new research showed most positively impacted student learning. It was a thankless job. Today I can assure you that the vast majority of teachers ignore all of that and do things they way they were taught themselves.

In all activities there will always be people who think the way they did things in the past is always best. Thinking people will instead evaluate potential changes as objectively as they can and either adapt those changes or not, with their decisions based upon a careful analysis rather than personal prejudice in favor of what they always did before.
 
I don't buy in to to the deep stop for recreational divers, unless it is a fudge factor for allowing divers with PFO's and various other medical problems into diving ( either these people should not be diving-- or they should have their own personal tables instead of relying on how big the fudge factor was)...

For that matter, I still like 60 for 60 air profiles... This whole "new science" thing is nonsense. If they want to make the tables more "scientific" , then the tables should be customized for each diver, at which time they could get away with saying they "improved" something...
 
In evaluating how necessary an ascent strategy is it is good to look at how it makes you feel at the end of the day. Many people report feeling better with deep stops. Richard Pyle who originated deep stops did. Of course staying too long at half max depth will eventually make things worse due to the extra gas loading. Whatever you do discuss it with you buddies pre-dive. Some computers will penalize you for deep stops so everyone needs to be working to the same plan going in.
 
I was always under the impression that if you are diving under a recreational profile, a safety stop wasn't really necessary but certainly nothing wrong with doing it. So now it's being suggested perhaps we should do a "deep stop" I think they call it and then the traditional stop at 15 ft. or whatever. Just seems like overkill to me.
 
I do notice that Im tired less when we do stops every 10 ft starting from the half of the depth and then doing slow (4-5) minute ascend from 20ft.
 

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