half stops

[palmm]

any thoughts on half stops. i have been reading about them and it sounds like it is safer diving practice. any thoughts.

 

[fdog]

If by "half stops", you're referring to beginning stops at half depth (kinda AKA min deco), then yes, I think it's a good idea. It addresses fast tissue desaturation, and I feel better with profiles that match min deco.

And it's pretty easy to fold this into a dive, so it's not like you're formally doing a specific ascent.


All the best, James

 

[TSandM]

The utility of deeper stops is currently a hot topic, and it is controversial as to whether they offer any benefit to the recreational diver. NAUI, I believe, has adopted a half maximal depth stop as a standard procedure, but I think they are alone in that. GUE uses minimum deco, beginning at half maximal depth.

The problem is that DCS is so unusual in recreational diving, absent gross violations of protocol, that any change in procedure is going to have a hard time showing a signficant decrease in clinical cases. I am not aware of any study comparing Dopper measurements of divers using a standard 3 minute safety stop type ascent with divers using the NAUI half maximal depth stop. Showing a substantial decrease in the number or size of bubbles would be suggestive evidence that the procedure is desirable, although the correlation between bubbles and sympatomatic DCS is not as clean as we would like it to be.

 

[PfcAJ]

From what I've read from DAN, GUE, the interwebs, and through personal experience, if you do them, great, if not, thats cool too. GUE recommends slowing the ascent down during the last 50% of the ascent.

I personally think it makes sense as it addresses those fast tissues and microbubble formation. But, as discussed earlier, DCS is the rec diver is a rare event. However, 1 in a million odds suck for that one dude. Any think I can do that could help and doesn't make it worse is something that I'll do.

 

[tomboyy]

Normally, anyone with half a brain would say " well .. if it's gonna be safer then its worth doing" and I would for the most part agree. The one thing I have a problem with is where does this stop.

To give an analogy, they use to say blood glucose levels were good at say 70 - 110 and then they changed it to 70 - 100 , now my lab now changed it to 70 - 99 . They did the same thing with lipid and ldld levels. My point is where does it stop ? Are they gonna say in the year 2015 that glucose levels need to be 70 -90 and on the scuba side we are gonna need to do stops at every 10 feets for 2 minutes with the last 15 feet broken up to a one minute stop at 15-10-5 feet?

Theres a risk to most of the things we do in life and we have to decide how far we are gonna go to be "safe" I'm just sayin

 

[palmm]

i agree with you that there is an inherent risk to diving. however just for the sake of discussion at what depth would you start doing half stops.

 

[knowone]

Servicing a Bend O Matic ten years ago I looked at the ceramicy pencil lead 1/4 to 1/2 inch long tissue simulator replicator thing and thought, how do big bubbles fit through this. So I thought small in small out read some books started experimenting and it makes me happy.

 

[knowone]

i agree with you that there is an inherent risk to diving. however just for the sake of discussion at what depth would you start doing half stops.

See heres the rub. Where have you been? What have you been doing there? How long have you been doing what you've been doing where you've been? How do you find slack bubbles? I don't know???????

 

[MXGratefulDiver]

any thoughts on half stops. i have been reading about them and it sounds like it is safer diving practice. any thoughts.

Forget about DCS and microbubbles for a moment and ask yourself why a recreational agency might be training divers to do a stop at half their deepest depth.

Might it be because ... like most of their curriculum ... it's geared toward the relatively unskilled diver who's either new or dives very occasionally and struggles with the finer aspects of buoyancy control?

I believe so.

In practical terms, what a half-stop does for you is it gets you to stop your ascent at a point where the expanding air spaces might otherwise make it easy for you to exceed your safe ascent limits ... a kind of "reset" before you begin the process again.

... it teaches you the art of coming up slowly ...

I believe that at a recreational level, that's the most practical benefit ...

... Bob (Grateful Diver)

 

[Lead_carrier]

ALERT DIVER,DAN's magazine, had an article in it's latest issue. If you are a member of DAN then you should have gotten it, if not, then it may be on their website. It had some good information in it.

Sometimes I do them, sometimes I don't. It just depends on my mood at any given time and whether I got rid of that pissed off shark.