Deep Stops Increases DCS
- Thread starter Divetech99
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
- Status
- Messages
- 7,660
- Reaction score
- 4,718
- # of dives
- 200 - 499
This is most interesting. It appears to be a problem rooted in the extrapolation of a shallower model. Such is always dangerous.
RGBM is (even today) reviled by many recreational depth divers as being too conservative. I learned it in 2005 from Dr. Timothy R. O'Leary himself. RGBM has treated me very well since then.
Though an amusing series of events, Dr. O'Leary had no free instructors to teach my son and I OW. He decided to take us on and we spent a week diving with him. It was magical, we took great advantage of the agency's permission for an instructor to teach beyond standards. I remain most amused by his constant stopping to reference NAUI standards as he 'couldn't remember the last time he taught OW' and had to cover core material exactly as it is stated. I believe that he was the head of NAUI Technical Operations at the time.
So, question:
RGBM is overly safe within recreational limits but will bend you like a pretzel at great depths. Does anyone know roughly about where the 'break even' depth is?
RGBM is (even today) reviled by many recreational depth divers as being too conservative. I learned it in 2005 from Dr. Timothy R. O'Leary himself. RGBM has treated me very well since then.
Though an amusing series of events, Dr. O'Leary had no free instructors to teach my son and I OW. He decided to take us on and we spent a week diving with him. It was magical, we took great advantage of the agency's permission for an instructor to teach beyond standards. I remain most amused by his constant stopping to reference NAUI standards as he 'couldn't remember the last time he taught OW' and had to cover core material exactly as it is stated. I believe that he was the head of NAUI Technical Operations at the time.
So, question:
RGBM is overly safe within recreational limits but will bend you like a pretzel at great depths. Does anyone know roughly about where the 'break even' depth is?
On the flip side of this VGE condition is what happens to the artVGE, and where does it go? Most of us make VGE, and a lot of us make artVGE in some amount in our dives, or after the dive.
Obviously, if we have a 10% re-circulation factor, they don't all pile up somewhere, because we have would have dropped dead long ago. It seems we have some natural tolerance of them or an ability to dissolve them. So where do artVGE go too?
There are several things I'm aware of. I asked Neal Pollock this question too, during his Deco stress presentation, at the TekDiveUSA in April. I'll get his answer off the tape later tomorrow, and post it on here.
.
Obviously, if we have a 10% re-circulation factor, they don't all pile up somewhere, because we have would have dropped dead long ago. It seems we have some natural tolerance of them or an ability to dissolve them. So where do artVGE go too?
There are several things I'm aware of. I asked Neal Pollock this question too, during his Deco stress presentation, at the TekDiveUSA in April. I'll get his answer off the tape later tomorrow, and post it on here.
.
Last edited:
Ayisha
Contributor
- Messages
- 7,660
- Reaction score
- 4,718
- # of dives
- 200 - 499
OK, I really wasn't trying to be a pain, but jeez, just answer the question in any one of so many different forms...
Ayisha
Contributor
It appears that no one knows quite where that sweet spot is...
yet
But according to at least 2 of the most expert opinions on this thread, it appears that 40/80 is a very good start.
yet
But according to at least 2 of the most expert opinions on this thread, it appears that 40/80 is a very good start.
UWSojourner
Contributor
It's been years since I've had access to a wide range of RGBM profiles (I used to have the GAP software). I do remember that it was pretty conservative at or near the NDL.
I'm accepting your language of "breakeven" since I think you mean by that the depth where the weaknesses of a more deep stop approach such as RGBM might start manifesting problems.
With that in mind, and based on some of the charts posted here, I'd say the "breakeven" is sooner than you'd think ... certainly you don't have to be diving "extreme" IMO. I'd see evidence in those charts (because we KNOW the result of the NEDU trials) that it's somewhere between your NDLs and those decompression stresses consistent with an air dive to 170ft for 30 minutes.
Last edited:
- Messages
- 7,660
- Reaction score
- 4,718
- # of dives
- 200 - 499
I get 23 minutes for 170 feet. My own 'home-brew' curve fit is 666,666 divided by depth and that number divided by depth again. (divide by D squared) But this is only my U/W guesstimate for the first real hard stop. (Also known as: NDL.)
Scary that where RGBM turns on you is that close, had no idea...
Scary that where RGBM turns on you is that close, had no idea...
UWSojourner
Contributor
- Messages
- 7,660
- Reaction score
- 4,718
- # of dives
- 200 - 499
Twice.
- Status
Similar threads
