Deep Stops

[Saturation]

Thanks BigJetDiver69, I concur! You've explained it very well.

Any theoretical models for the condition of tissues during on-off gassing requires a lot of computation, so how does one use only a calculator or just your head?

I'm not sure who developed this method, but it was a DIR diver who showed me this first and I don't know anyone who uses or knew of it prior to the GUE. One can estimate off-on gassing by taking the average depth of a dive. This estimate holds only for the NDL limits. The average depth is akin to the 'average' of your tissue exposure, putting together the net effect of on and off gassing.

Since this is only an estimate, the errors of this method become larger once in the decompression zone.

In the example above:

http://scubaboard.com/showpost.php?p=612679&postcount=7

[the above has a TYPO, 100' x 10 min = 1000 ft-min not 1100 ft-min.
The correct average depth = 1600 ft-min/20min = 80'.]

... a diver who dove to 100' for 10min and 60' for another 10 min, has loaded his tissues as if he dove to 80' and stayed there for 20min, i.e., the average depth.

 

[Curt Bowen]

Hi,

I just read a fascinating article in the recent Dive Training about the recent research into deep stops, that is taking a safety stop for one minute at half your deepest depth before slowly ascending for a 3 minute safety stop. The theory behind this seems to make sense. Basically, if you dive to 100 ft, make a one minute stop at 50 ft before the 3 minute safety stop at 15-20 ft.

Here is my question: How does one factor in multilevel diving? Often during multilevel dives, the dive will reach, say 100 ft, and then spend most of the dive time at 60 to 70. For deep stops, would one still make the 50 foot stop for make the deep stop at half the depth most time was spent?

Any thoughts?

Scubahiro

I feel all training agencies should change their openwater recreational no-decompression standards from a 3 minute safety stop to:

2 Minutes at 30 feet
2 Minutes at 10 feet

a 2 Minute at 20 could also be used if desired

The whole idea is to slow down the divers ascent towards the surface and allow the gas to come out of solution before it has a chance to form a micro bubble.

 

[Saturation]

I feel all training agencies should change their openwater recreational no-decompression standards from a 3 minute safety stop to:

2 Minutes at 30 feet
2 Minutes at 10 feet

a 2 Minute at 20 could also be used if desired

The whole idea is to slow down the divers ascent towards the surface and allow the gas to come out of solution before it has a chance to form a micro bubble.

l agree too. I would also add the mid-depth safety stop for 1-5 minutes.

 

[Curt Bowen]

l agree too. I would also add the mid-depth safety stop for 1-5 minutes.

I thought about this also but then remembered we are dealing with new divers who have hard time putting their fins on the right foot.

KISS - Keep it simple stupid

 

[pipedope]

The fins go on the FEET??????

Why didn't they teach me this in OW???

Oy Vey!


Just getting everybody to stop at least once on the way up is a start. The finer points of control and best ascent profile will be learned and practiced by those who wish to excel.

 

[Saturation]

I thought about this also but then remembered we are dealing with new divers who have hard time putting their fins on the right foot.
KISS - Keep it simple stupid

Oy, didn't think of it as a free ascent. Yes, I'm not sure many recreational divers can hold a depth. Most 'deep' dives often have descent or anchor lines the can grab on to.

 

[MechDiver]

Oy, didn't think of it as a free ascent. Yes, I'm not sure many recreational divers can hold a depth.

That, to me, would be the only reason to do it. Not only does it slow the ascent, it makes the diver aware of, and have to deal with, buoyancy control.

MD

 

[bullshark]

By way of explanation, if I may, until the Doc gets back:

Later research has shown that on-gassing occurs at one rate, and off-gassing occurs at a different rate (usually slower) for each half-time compartment. The relationship of the rate for each compartment, and over-all, is then described as NON-LINEAR.

Hope that helps! Cheers!

Cite please. I have not seen any conclusive research to support that.

 

[Saturation]

Cite please. I have not seen any conclusive research to support that.

Does this help?

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9074979

Basically, the rate of ingas is not the same rate as off gas.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=1887519

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2288040

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2089615

 

[Mako Mark]

I thought about this also but then remembered we are dealing with new divers who have hard time putting their fins on the right foot.

KISS - Keep it simple stupid

I have that problem, both my fins have "L" on them, I have tried to get a replacement with an "R", but cant find one anywhere.