Question on decompression models?

[kk4mei]

Coming back into diving after a 7 year break I came across an interesting video on YouTube about bubble model decompression profiles. My question is have we abandoned theses profiles all together and what are the current dive computer companies using now? When I stopped diving we were using V-planner to plan our long deco dives.


Here is the video:

https://www.youtube.com/watch?v=UY61...ature=youtu.be

[Kelly Jessop]

Coming back into diving after a 7 year break I came across an interesting video on YouTube about bubble model decompression profiles. My question is have we abandoned theses profiles all together and what are the current dive computer companies using now? When I stopped diving we were using V-planner to plan our long deco dives.


Here is the video:

https://www.youtube.com/watch?v=UY61...ature=youtu.be

Research has changed our understanding in the last years,but probably not in leaps and bounds. An interesting, and lengthy discussion that may be worth reading on Scubaboard under Technical Diving Specialties called," Deepstops increases DCS". There are quite a few informed postings by Dr Simon Mitchell which make it an interesting read.

[oya]

Oh Jesus. Does Ross have a username on this board?
If yes I'm going to hide in my closet until this thread blows over.

[oya]

Oh, and in response to your question:
Mostly you're going to find a lot of talk about ZHL16C with reasonably conservative gradient factors.

[Jax]

Well, let's see. The general consensus is that nobody really understands Decompresson Illness (DCI) or how it activates.

We come up with models that emperically give us 2.3% DCI if followed.

We input gas PO2 measured by a sensor with +/- 2% error that is read by a machine / computer with + / - 2% error.

We have thousands of physiological differences in each human being, compounded by thousands of environmental inputs specific to each human being.

And we wonder why we have DCI.

Just pick one.

[PfcAJ]

Well, let's see. The general consensus is that nobody really understands Decompresson Illness (DCI) or how it activates.

We come up with models that emperically give us 2.3% DCI if followed.

We input gas PO2 measured by a sensor with +/- 2% error that is read by a machine / computer with + / - 2% error.

We have thousands of physiological differences in each human being, compounded by thousands of environmental inputs specific to each human being.

And we wonder why we have DCI.

Just pick one.

Uhhh.....

[kk4mei]

Thanks I'll head over there and do some reading. The reason I ask is I just brought a Perdix dive computer and I'm trying to figure out what gradient factors to use. In the mid 2000's we mostly all used the NiTek He and V-Planner for backup tables. We did a few hundred dives in the 130'-160' range with this setup and had zero issues. I guess it's time to get all the older papers I still have on deep stops and al the publications put out from back then and brush up the catch up on the newer stuff.


So what gradient factors are most diving today?

[rddvet]

Thanks I'll head over there and do some reading. The reason I ask is I just brought a Perdix dive computer and I'm trying to figure out what gradient factors to use. In the mid 2000's we mostly all used the NiTek He and V-Planner for backup tables. We did a few hundred dives in the 130'-160' range with this setup and had zero issues. I guess it's time to get all the older papers I still have on deep stops and al the publications put out from back then and brush up the catch up on the newer stuff.


So what gradient factors are most diving today?

I would bet a huge number of people that own any shearwater computer (if not the majority) dive 30/70 because that's the default on shearwaters. I would also bet a good majority of those people don't understand what the 30/70 means. I read as much as I can because I think my understanding should be much better and honestly I'm still confused about a ton of it. Then again it's an evolving science and even the experts seem confused at times.

[kk4mei]

I would bet a huge number of people that own any shearwater computer (if not the majority) dive 30/70 because that's the default on shearwaters. I would also bet a good majority of those people don't understand what the 30/70 means. I read as much as I can because I think my understanding should be much better and honestly I'm still confused about a ton of it. Then again it's an evolving science and even the experts seem confused at times.

Your most likely right but I was lucky enough to start diving with a great group of technical divers from the very start. Although we were not cave divers we did agree to follow cave divers protocols because we always explored inside wrecks of the north east.


As for the 30/70 setting from the video I posted above 30% above ambient pressure may not be enough for the slower loading tissues to start off gassing. In the video the guy says he uses something like 50/75 +/-.


P.S I'm not trying to start a #### storm as I know sometime these conversations get interesting quickly.

[Jax]

As for the 30/70 setting from the video I posted above 30% above ambient pressure may not be enough for the slower loading tissues to start off gassing. In the video the guy says he uses something like 50/75 +/-.


P.S I'm not trying to start a #### storm as I know sometime these conversations get interesting quickly.

Interesting stuff here: What Deco Algoritm do you use?