Deep Stops Recreational Divers

[boulderjohn]

I was talking about the HelO2 which predates the Fused stuff by three or four years.

Here is what Suunto has to say about that on the site linked above:

Suunto Technical RGBM
An advanced algorithm that provides flexibility and safety during ascent through continuous decompression. Created especially to meet the needs of technical divers, it eliminates the need to constantly monitor depth, time, and when to switch gases, and means all critical data can be provided through a single device. Used in Suunto HelO2 and D9tx computers.

• Founded on the proven Suunto RGBM.
• Developed together with Dr. Bruce Wienke.

My point, regarding the OP, is that there is a whole class of 'deep stop' fudges quite like the ones in his poll but implemented by the computer. While almost nobody is now manually doing Pyle stops it would have been interesting to see how many are following the computer ones.

There is no point in running Pyle stops on an RGBM technical program, and to see why you should look at the article in which Pyle introduced the idea. In it, he mentions RGBM, which was already doing stops at that depth. If you look at the article I wrote, you will see that introducing a Pyle stop into a pure Bühlmann algorithm (which is what Pyle had in mind) produces a first stop at almost exactly the same depth as the RGBM algorithm.

The expert discussion of deep stops in the 2008 UHMS workshop failed to come up with a definition of deep stops, and that was largely the reason. The common definition of introducing a stop deeper than called for in your algorithm makes no sense when your algorithm already stops you at suich a depth--as in both the VPM and RGBM algorithms.

In your article you say

• With the deep stops setting on, the Suunto RGBM’s first stop was deeper than suggested by the NEDU study. When the deep stops setting was off, the first stop was within the safe range.

which sounds like an agreement that this supposedly bubble model is not doing excessively deep stops.

In the model tested in the study I quoted, that would be true. If the deep stop function was turned off, then it was not too deep. I have never dived with the HelO2, so I don't know how it works.

I got as far as trying to figure out if I had to join EUBS or SPUMS in order to read that paper before getting dragged back to real work.

I was given a copy of the study for the purposes of writing the article, with the understanding that I would not distribute it. The study is embargoed for a year and is only available from its original source until then.

 

[boulderjohn]

The topic of this thread is deep stops in recreational dives. The HelO2 is a computer designed for technical dives.

 

[KenGordon]

There is no point in running Pyle stops on an RGBM technical program

Indeed, but since Suunto RGBM is not RGBM having it as an option does have a point. Similarly for the other manufactures with this as an option on top of simple dissolved gas models.

I have never dived with the HelO2, so I don't know how it works.

It works just like a Zoop, but with some more aggressive settings available and this semi optional (may be ignored) Pyle style (ie short and inserted at arbitrary depths irrespective of gas load) stops.

The topic of this thread is deep stops in recreational dives. The HelO2 is a computer designed for technical dives.

That depends on what you call technical really. My Zoop does the same deco dives as my HelO2 so long as they are a single nitrox mix. Is the Zoop technical? I was messing with an entry level, single button, Cressi the other day and I think it had this deep stop option too.

 

[1atm]

http://ns.suunto.com/pdf/Suunto_Div...4375.32847960.1556699908-924026121.1551874233

View attachment 517192

I have difficulties getting my head around the red Suunto profile ... its average depth is deeper than the Buhlmann ones, yet it gets you out if the water some 16min earlier. I dont quite understand how this is supposed to work, assuming risk is the same ...

Also, while the continuous profile (red Suunto), vs the “step-shape” is better in theory, I have a hard time imagining how you would make sure to keep to this ideal, variable ascend rate in practice. It works for saturation divers, because you can control the chamber, but it doesnt look practical for a blue water ascend?

 

[kotik]

I have difficulties getting my head around the red Suunto profile ... its average depth is deeper than the Buhlmann ones, yet it gets you out if the water some 16min earlier. I dont quite understand how this is supposed to work, assuming risk is the same ...

Also, while the continuous profile (red Suunto), vs the “step-shape” is better in theory, I have a hard time imagining how you would make sure to keep to this ideal, variable ascend rate in practice. It works for saturation divers, because you can control the chamber, but it doesnt look practical for a blue water ascend?

That curve is showing a dive to 80M with just under an hour of deco, a little over five minutes of which is spent at the shallow stop. Just a gut reaction with no scientific reasoning to support it, but that seems pretty ballsy to me.

 

[barth]

Which is fundamentals min deco as taught currently. Which are not deep stops but merely a slowed ascent rate from 30’/min to 10’/ min.

When I did fundamentals and cave 1 the lecture did describe them as deepstops.

 

[dmaziuk]

That depends on what you call technical really. My Zoop does the same deco dives as my HelO2 so long as they are a single nitrox mix. Is the Zoop technical? I was messing with an entry level, single button, Cressi the other day and I think it had this deep stop option too.

It does, but it's optional and from RTFM'ing (I never enabled it on mine) it sounds more like a "PDIS".

Big difference between Cressi Leo and the Zoop is that if Cressi software includes a deco planner, I must have missed it in all those icons and buttons. So I think that one's clearly "non-technical".

 

[dmaziuk]

That curve is showing a dive to 80M with just under an hour of deco, a little over five minutes of which is spent at the shallow stop. Just a gut reaction with no scientific reasoning to support it, but that seems pretty ballsy to me.

Considering all the wailing and screaming lately, I'd've photoshoped out the 10/100 and 20/80 "comparison profiles" long ago fi I were Suunto.

 

[scubadada]

Thread is deep stops for recreational divers. No stop diving allows for direct ascent to the surface utilizing an appropriate ascent. The safety stop is optional, very commonly employed. If the deep stop (couple minutes at half max depth or something similar) was superior to the standard ascent, wouldn't it be the default rather than an option on most computers? I find it interesting that Shearwater does not offer deep stop option in rec mode. Of course, my Nitek Q offers neither a deep stop or a safety stop.