5:1 SCR Mode from a CCR

wondersea · 2nd May 2007, 08:28

Hi all,

I read in a thread some procedures to get in a SRC mode when you use your CCR.
In few word, I learned that you diluent flush every 5 breaths (5:1).

I read also that it depends of the depth you are and this ratio 5:1 is not allways the same. A formula can tell you this ratio.

I can't find this thread anymore neither the formula. Is it in Rebreather World or else ????

Some of you could tell me where is this discussion and / or develop and explain me about that.

paulraymaekers · 2nd May 2007, 08:40

Quote: (Originally Posted by wondersea)

Hi all,

I read in a thread some procedures to get in a SRC mode when you use your CCR.
In few word, I learned that you diluent flush every 5 breaths (5:1).

I read also that it depends of the depth you are and this ratio 5:1 is not allways the same. A formula can tell you this ratio.

I can't find this thread anymore neither the formula. Is it in Rebreather World or else ????

Some of you could tell me where is this discussion and / or develop and explain me about that.

the discussion is even more difficult: would the 5:1 ratio also hold for units that give a constant oxigen flow??? I suppose, if you're sure that the CMF is working, you could take a far higher ratio, not??

paul

CharlieT · 2nd May 2007, 13:17

Quote: (Originally Posted by wondersea)

Hi all,

I read in a thread some procedures to get in a SRC mode when you use your CCR.
In few word, I learned that you diluent flush every 5 breaths (5:1).

I read also that it depends of the depth you are and this ratio 5:1 is not allways the same. A formula can tell you this ratio.

I can't find this thread anymore neither the formula. Is it in Rebreather World or else ????

Some of you could tell me where is this discussion and / or develop and explain me about that.

Antoine

I am sorry if this reply is unhelpful but you learn how to use your unit SCR during Mod 1 or Mod 2.

Isn't it best (and safer) for you to ask your instructor about this procedure?

Charlie

**Dave Sutton** · 2nd May 2007, 14:30

Quote: (Originally Posted by wondersea)

Hi all,

I read in a thread some procedures to get in a SRC mode when you use your CCR.
In few word, I learned that you diluent flush every 5 breaths (5:1). .

5:1 is a pretty rough guess. It all depends on (1) depth, (2) exertion, and (3) the F02 in the diluent. Low 02 diluents don't give anywhere near the same advantage here as higher 02 diluents.

Using 5:1 at 30 meters with 21% diluent is going to be a huge waste of gas.

Trying 5:1 with 10% 02 diluent near the surface, for example, isn't going to work... not even for 1:1, never mind 5:1.......

Dave

wondersea · 2nd May 2007, 14:56

Quote: (Originally Posted by CharlieT)

Antoine

I am sorry if this reply is unhelpful but you learn how to use your unit SCR during Mod 1 or Mod 2.

Isn't it best (and safer) for you to ask your instructor about this procedure?

Charlie

Charlie,

Come on,

Not agree with you

In fact, I did the mod1 on Meg and dive with it conformly as my instructor teach me. For instance, in emergency case, I know that I can back in semi closed mode with one air diluent flush every 5 breaths and so on. I practice that way.

But, in order to progress you need also, by yourself, to have a better comprehension of the procedure not only by the only point of view of your instructor but sharing many experiences of other divers and other instructor.

The goal of Rebreather World is for that need, so I presume. If not, no need of RBW, no need to share, just be dummy diver with the only reference of your instructor and what you are understanding during 4 or 5 days.

Now, if the diver is so fool to do all what he read on any site and from anybody. He is a dead diver ! Safe diver has to select all informations he get even if they are coming from the best diver of Rebreather World or from his good instructor and he should improve his skill carefuly.

It's not because you know a skill or understand a problem that you will do it. But it's interesting to understand why people do that or that way and how.

I think more informations will be share, less accidents will be appears.

For an other example, I am not diving Trimix diluant because I am not yet train with it, but I can have some pertinent and technical question about it, because I study it a lot by myself ! So why don't answer me about this subject. It's not dangerous for me. But when I will do the course, I will be good prepared and the training will be more profitable.

So, I thing better, for well advised diver, to have answer to his questions by sharing experiences. Even if the answer may be difficult to understand or dangerous to experiment.

In this kind of technical diving, I really hope that divers are not dummy

Well, if you don't want to reply, it is your choice. But I don't think it's the spirit of Rebreather World.

**wedivebc** · 2nd May 2007, 15:48

Quote: (Originally Posted by paulraymaekers)

the discussion is even more difficult: would the 5:1 ratio also hold for units that give a constant oxigen flow??? I suppose, if you're sure that the CMF is working, you could take a far higher ratio, not??

paul

If the CMF is working why are you in SCR mode?
I think it all depends on what PPO2 your are happy with, both from a metabolic and decompression point of view.
I would suggect 1:5 would be OK at 30 meters but the ratio should decrease as you ascend.

paulraymaekers · 2nd May 2007, 16:02

Quote: (Originally Posted by wedivebc)

If the CMF is working why are you in SCR mode?
I think it all depends on what PPO2 your are happy with, both from a metabolic and decompression point of view.
I would suggect 1:5 would be OK at 30 meters but the ratio should decrease as you ascend.

eeuuhh.... I suggest you can go into SCR mode when you fall completely without electronics, but your mechanics still work perfect... no??
and than at 6m you go to oxigen CCR ..

and in that case it makes a difference if you have a CMF or not

you can go into SCR when out of oxigen too :-)

paul

**Dave Sutton** · 2nd May 2007, 16:03

Quote: (Originally Posted by wondersea)

In fact, I did the mod1 on Meg and dive with it conformly as my instructor teach me. For instance, in emergency case, I know that I can back in semi closed mode with one air diluent flush every 5 breaths and so on. I practice that way..

That ratio will work "OK' with air as diluent, is wasteful deeper and just "on the edge" at the surface.

If you have the time and energy, do an experiment: Flush the loop with pure diluent, and then watch the PP02 drop at various depths without 02 injected. Try at surface (be CAREFUL!!), 3 meters, 6 meters, 10 meters, 15, 20, and 30. Shallower is more dangerous, but also more useful (in example, if you know what it does at 10 meters you can do that also at 30... but it is not as efficient, but no danger).

This is a "no oxyygen available" emergency mode, and is something that EVERY advanced CCR diver must be able to do. It's *THE* way to survive "on the loop" after loss of ability to inject 02 AND a loss of electronics. Obviously, if you have the ability to monitor PPO02 it's not the best way.... simply SCC while watching the displays.

Irrespective of if you know how to count breaths, or rely on uxse of electonics for SCC use, maintainence of emergency diluent only SCC capability is THE reason to use diluents that are not artificially hypoxic when not needed.

Good discussion... keep asking questions. There are other emergency modes as well, but this ONE METHOD is THE KEYSTONE for the SCC mode, which is simply breath-counting. The thing that is nice is that the NUMBER of breaths is more or less constant at any depth without regard to workload. If you breath in a natural rythym (not "skip breathing"), your number of breaths per minute rises as your workload increases and falls as workload decreases. The oxygen extracted *per breath* remains almost constant. This means that you can learn to count for each depth of interest, and then use that count no matter what the workload.

EXPERT use of this method allows survivability with either no 02 AND/OR no electroncs. It's THE FIRST KEY towards a move to more thoughtful alpinism, if that is the goal, and ought to be second nature to any expert Rebreather diver.

The other required "Expert Survival Mode" is knowing how to maintain PP02 with 02 only AND no electronics..... that's a subject for another discussion. Juyst consider the following: An EXPERT Rebreather diver should be able to:

Survive with diluent only and electronics (SCC)
Survive with diliuent only and NO electronics (Beath-counting)
Survive with 02 only and electronics (no brainer)
Survive with 02 only and NO electronics (most tricky......)
Survive with diluent and oxygen BUT NO ELECTRONICS.

Master all of this, keep a dry loop, and you'll never need to go open circuit.

Dave

wondersea · 2nd May 2007, 17:33

Thank's Dave for this technical post and replacing the subject at his just value. You are right, that is a keystone skill.

It goes the way I want to read many point of vue on a subject as important as emergency skill. And fortunatly , it's in the same way I had learn it with my instructor but with another angle which make me better and stronger.

There is some few emergency pratice that can allowed you to stay on the loop in almost anycase (except maybe total innondation, but hard to arrive to this issue!) and by the way be safe, the good way to use a CCR

. You must choose the most elegant solution for each specific problem. Bail out is just to take time to be cool and make the good decision after analyze the problem if panic.

That's those one that I am praticing hard actually with my meg so my brain react the most quickly as possible without thinking.

For that, there will be no shadow or question in my mind. Just react

Even if people seems know the practice and why, I am not sure all are clean on it

I think it is profitable not only for me, new Rebreather diver, but for many RB divers.

More we read about emergency pratice, read and read and read, pratice and pratice and pratice again and again, more we can be cool, safe and a good diver !

There is all time a little bit more you can learn with sharing experiences.

Thank's to take time with us.

**wedivebc** · 2nd May 2007, 18:01

Quote: (Originally Posted by paulraymaekers)

eeuuhh.... I suggest you can go into SCR mode when you fall completely without electronics, but your mechanics still work perfect... no??

Right, sorry for the morning pre-coffee post.

2nd May 2007, 08:28	#1 (permalink)
wondersea New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2006 Location: France - Gerzat (63) - Sanary (83) Posts: 78	5:1 SCR Mode from a CCR Hi all, I read in a thread some procedures to get in a SRC mode when you use your CCR. In few word, I learned that you diluent flush every 5 breaths (5:1). I read also that it depends of the depth you are and this ratio 5:1 is not allways the same. A formula can tell you this ratio. I can't find this thread anymore neither the formula. Is it in Rebreather World or else ???? Some of you could tell me where is this discussion and / or develop and explain me about that. __________________ Antoine Pannetier DirRebreather member www.DIRRebreather.com
(Offline)

2nd May 2007, 08:40	#2 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,498	Re: 5:1 SCR Mode from a CCR Quote: (Originally Posted by wondersea) Hi all, I read in a thread some procedures to get in a SRC mode when you use your CCR. In few word, I learned that you diluent flush every 5 breaths (5:1). I read also that it depends of the depth you are and this ratio 5:1 is not allways the same. A formula can tell you this ratio. I can't find this thread anymore neither the formula. Is it in Rebreather World or else ???? Some of you could tell me where is this discussion and / or develop and explain me about that. the discussion is even more difficult: would the 5:1 ratio also hold for units that give a constant oxigen flow??? I suppose, if you're sure that the CMF is working, you could take a far higher ratio, not?? paul __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...
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2nd May 2007, 13:17	#3 (permalink)
CharlieT Custom Title Allowed! Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Nov 2005 Location: London Posts: 449	Re: 5:1 SCR Mode from a CCR Quote: (Originally Posted by wondersea) Hi all, I read in a thread some procedures to get in a SRC mode when you use your CCR. In few word, I learned that you diluent flush every 5 breaths (5:1). I read also that it depends of the depth you are and this ratio 5:1 is not allways the same. A formula can tell you this ratio. I can't find this thread anymore neither the formula. Is it in Rebreather World or else ???? Some of you could tell me where is this discussion and / or develop and explain me about that. Antoine I am sorry if this reply is unhelpful but you learn how to use your unit SCR during Mod 1 or Mod 2. Isn't it best (and safer) for you to ask your instructor about this procedure? Charlie
(Offline)

2nd May 2007, 14:30	#4 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Classic Kiss rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,689	Re: 5:1 SCR Mode from a CCR Quote: (Originally Posted by wondersea) Hi all, I read in a thread some procedures to get in a SRC mode when you use your CCR. In few word, I learned that you diluent flush every 5 breaths (5:1). . 5:1 is a pretty rough guess. It all depends on (1) depth, (2) exertion, and (3) the F02 in the diluent. Low 02 diluents don't give anywhere near the same advantage here as higher 02 diluents. Using 5:1 at 30 meters with 21% diluent is going to be a huge waste of gas. Trying 5:1 with 10% 02 diluent near the surface, for example, isn't going to work... not even for 1:1, never mind 5:1....... Dave __________________ "Changes in Lattitudes, Changes in Attitudes, Nothing remains quite the same".... www.nobubblediving.com
(Offline)

2nd May 2007, 14:56	#5 (permalink)
wondersea New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2006 Location: France - Gerzat (63) - Sanary (83) Posts: 78	Re: 5:1 SCR Mode from a CCR Quote: (Originally Posted by CharlieT) Antoine I am sorry if this reply is unhelpful but you learn how to use your unit SCR during Mod 1 or Mod 2. Isn't it best (and safer) for you to ask your instructor about this procedure? Charlie Charlie, Come on, Not agree with you In fact, I did the mod1 on Meg and dive with it conformly as my instructor teach me. For instance, in emergency case, I know that I can back in semi closed mode with one air diluent flush every 5 breaths and so on. I practice that way. But, in order to progress you need also, by yourself, to have a better comprehension of the procedure not only by the only point of view of your instructor but sharing many experiences of other divers and other instructor. The goal of Rebreather World is for that need, so I presume. If not, no need of RBW, no need to share, just be dummy diver with the only reference of your instructor and what you are understanding during 4 or 5 days. Now, if the diver is so fool to do all what he read on any site and from anybody. He is a dead diver ! Safe diver has to select all informations he get even if they are coming from the best diver of Rebreather World or from his good instructor and he should improve his skill carefuly. It's not because you know a skill or understand a problem that you will do it. But it's interesting to understand why people do that or that way and how. I think more informations will be share, less accidents will be appears. For an other example, I am not diving Trimix diluant because I am not yet train with it, but I can have some pertinent and technical question about it, because I study it a lot by myself ! So why don't answer me about this subject. It's not dangerous for me. But when I will do the course, I will be good prepared and the training will be more profitable. So, I thing better, for well advised diver, to have answer to his questions by sharing experiences. Even if the answer may be difficult to understand or dangerous to experiment. In this kind of technical diving, I really hope that divers are not dummy Well, if you don't want to reply, it is your choice. But I don't think it's the spirit of Rebreather World. __________________ Antoine Pannetier DirRebreather member www.DIRRebreather.com
(Offline)

2nd May 2007, 15:48	#6 (permalink)
wedivebc Dave Tomblin Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,447	Re: 5:1 SCR Mode from a CCR Quote: (Originally Posted by paulraymaekers) the discussion is even more difficult: would the 5:1 ratio also hold for units that give a constant oxigen flow??? I suppose, if you're sure that the CMF is working, you could take a far higher ratio, not?? paul If the CMF is working why are you in SCR mode? I think it all depends on what PPO2 your are happy with, both from a metabolic and decompression point of view. I would suggect 1:5 would be OK at 30 meters but the ratio should decrease as you ascend. __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
(Online)

2nd May 2007, 16:02	#7 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,498	Re: 5:1 SCR Mode from a CCR Quote: (Originally Posted by wedivebc) If the CMF is working why are you in SCR mode? I think it all depends on what PPO2 your are happy with, both from a metabolic and decompression point of view. I would suggect 1:5 would be OK at 30 meters but the ratio should decrease as you ascend. eeuuhh.... I suggest you can go into SCR mode when you fall completely without electronics, but your mechanics still work perfect... no?? and than at 6m you go to oxigen CCR .. and in that case it makes a difference if you have a CMF or not you can go into SCR when out of oxigen too :-) paul __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...
(Offline)

2nd May 2007, 16:03	#8 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Classic Kiss rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,689	Re: 5:1 SCR Mode from a CCR Quote: (Originally Posted by wondersea) In fact, I did the mod1 on Meg and dive with it conformly as my instructor teach me. For instance, in emergency case, I know that I can back in semi closed mode with one air diluent flush every 5 breaths and so on. I practice that way.. That ratio will work "OK' with air as diluent, is wasteful deeper and just "on the edge" at the surface. If you have the time and energy, do an experiment: Flush the loop with pure diluent, and then watch the PP02 drop at various depths without 02 injected. Try at surface (be CAREFUL!!), 3 meters, 6 meters, 10 meters, 15, 20, and 30. Shallower is more dangerous, but also more useful (in example, if you know what it does at 10 meters you can do that also at 30... but it is not as efficient, but no danger). This is a "no oxyygen available" emergency mode, and is something that EVERY advanced CCR diver must be able to do. It's THE way to survive "on the loop" after loss of ability to inject 02 AND a loss of electronics. Obviously, if you have the ability to monitor PPO02 it's not the best way.... simply SCC while watching the displays. Irrespective of if you know how to count breaths, or rely on uxse of electonics for SCC use, maintainence of emergency diluent only SCC capability is THE reason to use diluents that are not artificially hypoxic when not needed. Good discussion... keep asking questions. There are other emergency modes as well, but this ONE METHOD is THE KEYSTONE for the SCC mode, which is simply breath-counting. The thing that is nice is that the NUMBER of breaths is more or less constant at any depth without regard to workload. If you breath in a natural rythym (not "skip breathing"), your number of breaths per minute rises as your workload increases and falls as workload decreases. The oxygen extracted per breath remains almost constant. This means that you can learn to count for each depth of interest, and then use that count no matter what the workload. EXPERT use of this method allows survivability with either no 02 AND/OR no electroncs. It's THE FIRST KEY towards a move to more thoughtful alpinism, if that is the goal, and ought to be second nature to any expert Rebreather diver. The other required "Expert Survival Mode" is knowing how to maintain PP02 with 02 only AND no electronics..... that's a subject for another discussion. Juyst consider the following: An EXPERT Rebreather diver should be able to: Survive with diluent only and electronics (SCC) Survive with diliuent only and NO electronics (Beath-counting) Survive with 02 only and electronics (no brainer) Survive with 02 only and NO electronics (most tricky......) Survive with diluent and oxygen BUT NO ELECTRONICS. Master all of this, keep a dry loop, and you'll never need to go open circuit. Dave __________________ "Changes in Lattitudes, Changes in Attitudes, Nothing remains quite the same".... www.nobubblediving.com Last edited by Dave Sutton : 2nd May 2007 at 16:09.
(Offline)

2nd May 2007, 17:33	#9 (permalink)
wondersea New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2006 Location: France - Gerzat (63) - Sanary (83) Posts: 78	Re: 5:1 SCR Mode from a CCR Thank's Dave for this technical post and replacing the subject at his just value. You are right, that is a keystone skill. It goes the way I want to read many point of vue on a subject as important as emergency skill. And fortunatly , it's in the same way I had learn it with my instructor but with another angle which make me better and stronger. There is some few emergency pratice that can allowed you to stay on the loop in almost anycase (except maybe total innondation, but hard to arrive to this issue!) and by the way be safe, the good way to use a CCR . You must choose the most elegant solution for each specific problem. Bail out is just to take time to be cool and make the good decision after analyze the problem if panic. That's those one that I am praticing hard actually with my meg so my brain react the most quickly as possible without thinking. For that, there will be no shadow or question in my mind. Just react Even if people seems know the practice and why, I am not sure all are clean on it I think it is profitable not only for me, new Rebreather diver, but for many RB divers. More we read about emergency pratice, read and read and read, pratice and pratice and pratice again and again, more we can be cool, safe and a good diver ! There is all time a little bit more you can learn with sharing experiences. Thank's to take time with us. __________________ Antoine Pannetier DirRebreather member www.DIRRebreather.com
(Offline)

2nd May 2007, 18:01	#10 (permalink)
wedivebc Dave Tomblin Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,447	Re: 5:1 SCR Mode from a CCR Quote: (Originally Posted by paulraymaekers) eeuuhh.... I suggest you can go into SCR mode when you fall completely without electronics, but your mechanics still work perfect... no?? Right, sorry for the morning pre-coffee post. __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
(Online)

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