When are deep stops effective??

[redacted]

It sure would be nice if dive computers gave an indication of when the controlling compartment starts off-gassing. The information is there and just a matter of providing a simple display (Icon or flashing indicator). Other than intertrupting an ascent that could be too fast, deep stops seem to be counter-productive if the controlling compartment is still loading. I would not mind seeing what compartment is the controlling compartment as it would provide a basis for planning the duration of a rest stop but that may get a bit complex both from a display and a user response aspect. Probably more than most divers would want to know or have any idea what to do with it.

 

[ed.hamilton1]

My understanding is that deep stops improves off gassing for fast tissue compartments such as the blood and spinal fluid better than a slow ascent rate which can be especially important for recreational diving. However although this is an option available on my sunto computer I find it much easier just to pick a bit of reef to circle round for five minutes at the end of the dive and then follow the standard safety stop guideline settings.

 

[ed.hamilton1]

Did a quick check through DAN and they go into some detail about this subject I have attached a link below and also I have included a couple of interesting paragraphs from the article.

International DAN research studies have recently clearly confirmed these hypotheses: 15 divers were enrolled in a study and each given eight possible combinations of ascent rates, and either a shallow stop, or a deep and a shallow stop. The repetitive dives were to 80 feet (25 meters) for 25 minutes; the surface interval was three hours, 30 minutes; and the final dive was to 80 feet for 20 minutes. Ascent rates were 60, 30 and 10 feet per minute. The matrix is shown in Table 3 and the results of 181 dives are shown in Table 4.
Clearly, the best decompression schedule is Profile 6 (see highlights in both tables). With an ascent rate of 33 feet (10 meters) per minute, and two stops at 45 feet (13.5 meters) and 9 feet (2.7 meters) respectively, this profile had the lowest bubble score of 1.76.


NAUI technical divers have used the Wienke RGBM model quite extensively with no recorded incidence of DCS. This data as well as the results of this IDAN research in divers were discussed at a NAUI workshop in Florida in early 2003. As a result, NAUI has now suggested that a deep stop might well be incorporated in recreational diving by taking a one-minute stop at half the depth and followed by a two-minute safety stop at the 15- to 20-foor level instead of the three minutes currently recommended. We are currently testing this concept with our Italian diver research teams.

DAN | News.

Hope you find this useful.

 

[ajduplessis]

On all dives!!

 

[Doppler]

Deleted

 

[DiveNav]

...... I would not mind seeing what compartment is the controlling compartment as it would provide a basis for planning the duration of a rest stop .....

Something like this?

​

Alberto (aka eDiver)

 

[Hatul]

It sure would be nice if dive computers gave an indication of when the controlling compartment starts off-gassing. The information is there and just a matter of providing a simple display (Icon or flashing indicator). Other than intertrupting an ascent that could be too fast, deep stops seem to be counter-productive if the controlling compartment is still loading. I would not mind seeing what compartment is the controlling compartment as it would provide a basis for planning the duration of a rest stop but that may get a bit complex both from a display and a user response aspect. Probably more than most divers would want to know or have any idea what to do with it.

I also would like to know. In Suunto this is called the floor, above which you're offgassing the controlling compartment. It only shows this in an indirect way with an upward triangle when in deco mode and below the floor.

The Galileo Sol gives deep stops just above the floor so you don't increase your decompression requirement. But none of them actually shows what that floor depth is.

 

[Jax]

Did a quick check through DAN and they go into some detail about this subject I have attached a link below and also I have included a couple of interesting paragraphs from the article.

International DAN research studies have recently clearly confirmed these hypotheses: 15 divers were enrolled in a study and each given eight possible combinations of ascent rates, and either a shallow stop, or a deep and a shallow stop. The repetitive dives were to 80 feet (25 meters) for 25 minutes; the surface interval was three hours, 30 minutes; and the final dive was to 80 feet for 20 minutes. Ascent rates were 60, 30 and 10 feet per minute. The matrix is shown in Table 3 and the results of 181 dives are shown in Table 4.
Clearly, the best decompression schedule is Profile 6 (see highlights in both tables). With an ascent rate of 33 feet (10 meters) per minute, and two stops at 45 feet (13.5 meters) and 9 feet (2.7 meters) respectively, this profile had the lowest bubble score of 1.76.


NAUI technical divers have used the Wienke RGBM model quite extensively with no recorded incidence of DCS. This data as well as the results of this IDAN research in divers were discussed at a NAUI workshop in Florida in early 2003. As a result, NAUI has now suggested that a deep stop might well be incorporated in recreational diving by taking a one-minute stop at half the depth and followed by a two-minute safety stop at the 15- to 20-foor level instead of the three minutes currently recommended. We are currently testing this concept with our Italian diver research teams.

DAN | News.

Hope you find this useful.

The above link is old, from 2004.

An updated version is here: Alert Diver | Deep Stops

 

[Jax]

I also would like to know. In Suunto this is called the floor, above which you're offgassing the controlling compartment. It only shows this in an indirect way with an upward triangle when in deco mode and below the floor.

The Galileo Sol gives deep stops just above the floor so you don't increase your decompression requirement. But none of them actually shows what that floor depth is.

Y'all do realize that there really isn't one "compartment" that exists - these are theoretical catagories that are assigned on-gas and off-gas rates to mimic various tissues throughout the body?

It's all theory, your own phisology has its own reactions, affected by what rest, food, drink you had, . . .

Seriously, you are asking people to compute the exact time in which a SWAG of a WAG happens . . . .

 

[Jax]

The above link is old, from 2004.

An updated version is here: Alert Diver | Deep Stops

From above:

In the mid-1990s, Richard Pyle, a biomarine scientist who frequently made dives to great depths in search of fish species, noticed that sometimes he felt fatigued after dives, and at other times he felt normal. An excellent observer and trained scientist, he figured out that on dives when he had to stop during his ascent to deflate the swim bladders of his specimens, he felt much better. Soon he introduced a brief stop halfway to the surface on all his dives and formed the strong opinion that this significantly reduced his post-dive fatigue. He shared his experience with fellow divers, and the practice of deep stops became widespread among technical divers before it could be scientifically tested.