CCR Trimix Simplified by Mel Clark question

wondersea · 21st December 2007, 06:46

Hi,

I think also, it's better to stay on loop or SCR as long as I can and bailout is the last way.

When on bailout, it's really hard to go back to the loop in my mind and if I go to OC, then immediatly I start OC procedure and forget the loop. It's an emergency situation where you have lot of think to do quickly and don't have time to think, just act and get out of here.

Anyway my X1 can't go back to CCR mode if you switch to bailout plan !
You decide bailout, you stay bailout.

And I think it's a good way.

Mikel-Deko · 21st December 2007, 07:48

Hi

NAD: sorry if you think that i've been complaining about the book.
It is just a thought, a feeling that sometimes the easyest solution is not the best.
In the other hand, i've been writing also one manual and i'm always open to hear people pointing me some ideas.
If you read my posts, you will see that i said the book is fenomenal. It is just that i wanted to open a discusíon about something that i think is not absolutely correct.

JOE: i agree with you absolutely. 30 minutes deco ahead with enaught bailout is not the scenario that we wanted to disccus.
Say 90 minutes deco with just the necesary bailout.

For how to bailout there have been some discusion. Alpin stile, team bailout, etc...

Been the easyest is the best to go to OC?

Well i don't think that is easier to go to OC.

Maybe can be the way than some people have been teach. Any problem===> OC.

Just thoutgh that come to my head.

Best

Merry Christmas.

Mikel

scubagrunt · 21st December 2007, 08:23

Quote: (Originally Posted by Mikel-Deko)

Hi,

Maybe is my fealing but i don't think that the best solution for some problems in CCR trimix is going to OC as Mel sais in the book.

I think that for air dives, i mean maximum of 40 mtrs, it could be a goog solution, but for Trimix dives, i don't think so.

Please, any commentary will be welcome.

Best

Mikel

Happy hollidays !!!

Hi Guys,
I want to clear up some perhaps misunderstanding here. First off I say in the book EITHER go to OC or do a vigilant loop flush, then decide. The reason I do not say just do a loop flush is because there are some units out there that are harder to flush than others and if you FEEL FUNNY and tried to do a loop flush before doing OC “sanity” breathes you would be dead. Remember some units have BOV’s and some flush fast. So it depends on the unit. But what I am saying is get some good gas FAST. So I say either do a loop flush or go to OC now you have bought time, albeit only a little. Now decide. Of course I say OC is the best option, it really is. When you FEEL FUNNY you have just been given a second chance at life, don’t waste it on second-guessing a loop that made you FEEL FUNNY. There is a difference here between noticing something is wrong i.e. Seeing a PO2 of 1.7 and FEELING FUNNY. If you notice a PO2 of 1.7 and don’t feel funny then yes just do a loop flush and trouble shoot why the PO2 made it to 1.7. If however you feel funny or feel funny and notice a high (or low) PO2 then you had better move fast. So I suggest OC for CCRs with BOV’s and a loop flush for CCRs with a high flow ADV. Then OC bailout, or if you must (because you did not carry enough bailout gas to complete a safe assent) go back to the loop and trouble shoot and perhaps fix the problem. I do in the manual suggest OC as the number one choice, then I also go into details of other methods to stay on the loop. I call it adding tools to your toolbox, so when you are in the situation you can respond faster and with better accuracy. Now some of those options that I suggested in the manual include:

Open loop
Flushing a flooded loop (assuming this is possible on the specific CCR)
SCR mode
Oxygen CCR mode
Dealing with oxygen sensor failure and still staying on the loop
Dealing with the three H’s and still staying on the loop
Complete electronic failure and staying on the loop
Caustic cocktail sorry this means get off the loop!
Dealing with an internal and a external “BOOM” and staying on the unit
What if game for PO2 issues and staying on the unit
What if game for display issues and staying on the unit
What if game for fuel cell issues and staying on the unit

So I feel that yes I suggest going to OC is the best option and once again it is if you carry enough bailout, but then I also give the reader a lot of options of how to stay on the loop if they choose too. I think that anyone who decides to stay on a questionable loop after FEELING FUNNY is really asking for it. How do you know why you feel funny? Is it hyperoxia, is it hypoxia, is it hypercapnia? Take the warning and go home alive. All of us who CCR dive need to stop and remember our families and loved ones when we make decisions on staying on the loop or getting off the loop. The question in our heads should be how would my wife, husband, kids, parents etc feel about my decision. How would they feel if I did not come home tonight? Sorry to be so blunt here but this is a very important topic that most of us may have forgotten when we make decisions underwater. Also using SCR mode for a questionable scrubber is highly risky; why not go to OC and bailout? SCR can be used for say electronic loss, but for a crashed scrubber, not me! Also SCR mode is fairly unreliable for knowing the gas in the loop and the resulting decompression (assuming an electronics failure). So yes I explain SCR mode in the manual for completeness, but it really is a risky move that should only be completed if in a dire situation. I also want to point out that the manual is a generic rebreather trimix manual. As such it covers the basic principles of trimix on a CCR. Every different CCR has a different design and as such requires slightly different emergency responses. This is why this manual is meant to be used in conjunction with professional training so your instructor can go over unit specific differences and procedures.
Another thought on all of this is all of these skills are important, but they will not serve you any good if you do not practice them! So my advice to anyone who will listen is practice your skills, if you want to use SCR mode go ahead and practice it and watch your PO2 then maybe in a real emergency this skill may serve you well. Otherwise all this talk is just that talk. A final note on staying on the loop. Why is it we feel that in MOD 1 or air diluent that OC is the answer then once we move to MOD 2 and 3 or trimix we all of a sudden have the powers of a “gas mass spectrometer” and we can go back to a loop that made use FEEL FUNNY (i.e. tried to kill us) and analyze it and fix it. Once again all of this is just my humble opinions, everyone is entitled to there own opinions.
mel

jhaaja · 21st December 2007, 09:05

Great post and you seem to be on the same page as me! I think I need to buy your book too

Have some GREEN!

JH

***jradomski*** · 21st December 2007, 09:23

Quote: (Originally Posted by scubagrunt)

Also SCR mode is fairly unreliable for knowing the gas in the loop and the resulting decompression (assuming an electronics failure). So yes I explain SCR mode in the manual for completeness, but it really is a risky move that should only be completed if in a dire situation.
mel

Hi mel,
I have to strongly disagree here if you have done the proper practice.. if not all bets are off

On the ANDI L3 class we make a student do 30 mins on scr mode (using an offboard gas source) while doing a simulated deco (IE ascent starting at 21m), all the time they are recording their results (hi and low points).. If they cant keep it within .1 of the target po2 , they do another dive until they get it right.. Students when properly trained can usually maintain -.05 to -0.07 quite confortably at 9m or deeper.. I know I am usually around .03 of target on most rigs.. This makes deco bailout calcs easy..

The target does not necessarily have to be the po2 flush either, the key is CONSISTENCY.. This is what I mean, lets say on a flush a gas gives a 1.6, they get the 1.6 on a thorough flush but on a "refill breath" they only get a 1.5, BUT on subsequent refils they always get a 1.5 and not a constantly dropping po2 (lower on each refill)... This is also acceptable since they could plan the "deco" mix for this (using the lowest value).. If they are inconsistent they can do complete flushes at regular periods to get the loop back to a known value.. the key is the person learns their limits, if you have not done it this way you really don;t know what you are capable of, and therefore you don't know what your options really are.. This also needs to be practiced to remain proficient, not just taught, tried and filed for future use.. What normall happens is at the start people are a bit inconsistent but with a few minutes they get into a rythm and things usually get pretty stable..

I find it easist to do on a rig where the ADV can be fully disabled..

jo_c · 21st December 2007, 13:04

I don't know if it's just me, but it seems crazy to stay on the loop if I'm having CO2 breakthrough because *some* of the CO2 will get scrubbed out. Especially when you have perfectly good OC gas sat there.

Same as I don't think I'd be running SCR mode on ascent if I had no displays to tell me exactly what PO2 I'm breathing.

I have planned bailout gas for the dive.. obviously if you don't take enough bailout for the dive that's a different matter....

Just my opinion.

wondersea · 21st December 2007, 13:26

I can tell you, with a Meg, you can fine tune SCR mode even without electronique. Just practice skill and verify then trust you and the Meg. For deco, just make like OC diluent.

silentscuba · 21st December 2007, 16:04

So, what some of you are saying is that you use to much gas on OC bailout and you don't carry enough so you need to stay on the loop inorder to make things work out OK.

What happens if you can't stay on the loop!!! that can happen also. You now have a second problem to solve if you don't have enough bailout with you.

I still don't understand why someone would try and figure out a problem by staying on the loop risking their life and then on top of that not have enough bailout in case they can't.

We still need to plan for the worst case (carry enough bailout) and hope for the best (maybe staying on the loop) if you can work out the problem.

In any case, you should still have enough bailout, and should not take a risk staying on a loop if it is not very clear what is wrong.

Just my own opinion

.

Sounds like a Bail Out CCR would be a good thing!!!

wondersea · 21st December 2007, 16:28

I am talking for me, even if I think I can stay on the loop and OC bailout is the last option, I allways carry enough bailout for the worst case

If not, It's fool option and I want to be an old happy CCR diver

curt · 21st December 2007, 16:49

Hi Mel,

Thanks for the clarifications, and the great work on getting this book produced.

21st December 2007, 06:46	#31 (permalink)
wondersea New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2006 Location: France - Gerzat (63) - Sanary (83) Posts: 78	Re: CCR Trimix Simplified by Mel Clark question Hi, I think also, it's better to stay on loop or SCR as long as I can and bailout is the last way. When on bailout, it's really hard to go back to the loop in my mind and if I go to OC, then immediatly I start OC procedure and forget the loop. It's an emergency situation where you have lot of think to do quickly and don't have time to think, just act and get out of here. Anyway my X1 can't go back to CCR mode if you switch to bailout plan ! You decide bailout, you stay bailout. And I think it's a good way. __________________ Antoine Pannetier DirRebreather member www.DIRRebreather.com
(Online)

21st December 2007, 07:48	#32 (permalink)
Mikel-Deko Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: Basque Country -Sp- Posts: 448	Re: CCR Trimix Simplified by Mel Clark question Hi NAD: sorry if you think that i've been complaining about the book. It is just a thought, a feeling that sometimes the easyest solution is not the best. In the other hand, i've been writing also one manual and i'm always open to hear people pointing me some ideas. If you read my posts, you will see that i said the book is fenomenal. It is just that i wanted to open a discusíon about something that i think is not absolutely correct. JOE: i agree with you absolutely. 30 minutes deco ahead with enaught bailout is not the scenario that we wanted to disccus. Say 90 minutes deco with just the necesary bailout. For how to bailout there have been some discusion. Alpin stile, team bailout, etc... Been the easyest is the best to go to OC? Well i don't think that is easier to go to OC. Maybe can be the way than some people have been teach. Any problem===> OC. Just thoutgh that come to my head. Best Merry Christmas. Mikel __________________ Mikel-Deko Basque Country www.olatu.net "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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21st December 2007, 08:23	#33 (permalink)
scubagrunt CCR Diva Current Rebreather/s: Inspiration Classic Megalodon Classic Kiss Optima rEvo Other CCR Other SCR Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Evolution Megalodon Sport Kiss Classic Kiss Optima rEvo Other CCR Other SCR Join Date: May 2005 Location: Washington Posts: 429	Re: CCR Trimix Simplified by Mel Clark question Quote: (Originally Posted by Mikel-Deko) Hi, Maybe is my fealing but i don't think that the best solution for some problems in CCR trimix is going to OC as Mel sais in the book. I think that for air dives, i mean maximum of 40 mtrs, it could be a goog solution, but for Trimix dives, i don't think so. Please, any commentary will be welcome. Best Mikel Happy hollidays !!! Hi Guys, I want to clear up some perhaps misunderstanding here. First off I say in the book EITHER go to OC or do a vigilant loop flush, then decide. The reason I do not say just do a loop flush is because there are some units out there that are harder to flush than others and if you FEEL FUNNY and tried to do a loop flush before doing OC “sanity” breathes you would be dead. Remember some units have BOV’s and some flush fast. So it depends on the unit. But what I am saying is get some good gas FAST. So I say either do a loop flush or go to OC now you have bought time, albeit only a little. Now decide. Of course I say OC is the best option, it really is. When you FEEL FUNNY you have just been given a second chance at life, don’t waste it on second-guessing a loop that made you FEEL FUNNY. There is a difference here between noticing something is wrong i.e. Seeing a PO2 of 1.7 and FEELING FUNNY. If you notice a PO2 of 1.7 and don’t feel funny then yes just do a loop flush and trouble shoot why the PO2 made it to 1.7. If however you feel funny or feel funny and notice a high (or low) PO2 then you had better move fast. So I suggest OC for CCRs with BOV’s and a loop flush for CCRs with a high flow ADV. Then OC bailout, or if you must (because you did not carry enough bailout gas to complete a safe assent) go back to the loop and trouble shoot and perhaps fix the problem. I do in the manual suggest OC as the number one choice, then I also go into details of other methods to stay on the loop. I call it adding tools to your toolbox, so when you are in the situation you can respond faster and with better accuracy. Now some of those options that I suggested in the manual include: Open loop Flushing a flooded loop (assuming this is possible on the specific CCR) SCR mode Oxygen CCR mode Dealing with oxygen sensor failure and still staying on the loop Dealing with the three H’s and still staying on the loop Complete electronic failure and staying on the loop Caustic cocktail sorry this means get off the loop! Dealing with an internal and a external “BOOM” and staying on the unit What if game for PO2 issues and staying on the unit What if game for display issues and staying on the unit What if game for fuel cell issues and staying on the unit So I feel that yes I suggest going to OC is the best option and once again it is if you carry enough bailout, but then I also give the reader a lot of options of how to stay on the loop if they choose too. I think that anyone who decides to stay on a questionable loop after FEELING FUNNY is really asking for it. How do you know why you feel funny? Is it hyperoxia, is it hypoxia, is it hypercapnia? Take the warning and go home alive. All of us who CCR dive need to stop and remember our families and loved ones when we make decisions on staying on the loop or getting off the loop. The question in our heads should be how would my wife, husband, kids, parents etc feel about my decision. How would they feel if I did not come home tonight? Sorry to be so blunt here but this is a very important topic that most of us may have forgotten when we make decisions underwater. Also using SCR mode for a questionable scrubber is highly risky; why not go to OC and bailout? SCR can be used for say electronic loss, but for a crashed scrubber, not me! Also SCR mode is fairly unreliable for knowing the gas in the loop and the resulting decompression (assuming an electronics failure). So yes I explain SCR mode in the manual for completeness, but it really is a risky move that should only be completed if in a dire situation. I also want to point out that the manual is a generic rebreather trimix manual. As such it covers the basic principles of trimix on a CCR. Every different CCR has a different design and as such requires slightly different emergency responses. This is why this manual is meant to be used in conjunction with professional training so your instructor can go over unit specific differences and procedures. Another thought on all of this is all of these skills are important, but they will not serve you any good if you do not practice them! So my advice to anyone who will listen is practice your skills, if you want to use SCR mode go ahead and practice it and watch your PO2 then maybe in a real emergency this skill may serve you well. Otherwise all this talk is just that talk. A final note on staying on the loop. Why is it we feel that in MOD 1 or air diluent that OC is the answer then once we move to MOD 2 and 3 or trimix we all of a sudden have the powers of a “gas mass spectrometer” and we can go back to a loop that made use FEEL FUNNY (i.e. tried to kill us) and analyze it and fix it. Once again all of this is just my humble opinions, everyone is entitled to there own opinions. mel __________________ "No good deed goes unpunished!" www.silentscuba.com Last edited by scubagrunt : 21st December 2007 at 08:25.
(Offline)

21st December 2007, 09:05	#34 (permalink)
jhaaja Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Mar 2005 Location: Finland Posts: 884	Re: CCR Trimix Simplified by Mel Clark question Great post and you seem to be on the same page as me! I think I need to buy your book too Have some GREEN! JH
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21st December 2007, 09:23	#35 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,993	Re: CCR Trimix Simplified by Mel Clark question Quote: (Originally Posted by scubagrunt) Also SCR mode is fairly unreliable for knowing the gas in the loop and the resulting decompression (assuming an electronics failure). So yes I explain SCR mode in the manual for completeness, but it really is a risky move that should only be completed if in a dire situation. mel Hi mel, I have to strongly disagree here if you have done the proper practice.. if not all bets are off On the ANDI L3 class we make a student do 30 mins on scr mode (using an offboard gas source) while doing a simulated deco (IE ascent starting at 21m), all the time they are recording their results (hi and low points).. If they cant keep it within .1 of the target po2 , they do another dive until they get it right.. Students when properly trained can usually maintain -.05 to -0.07 quite confortably at 9m or deeper.. I know I am usually around .03 of target on most rigs.. This makes deco bailout calcs easy.. The target does not necessarily have to be the po2 flush either, the key is CONSISTENCY.. This is what I mean, lets say on a flush a gas gives a 1.6, they get the 1.6 on a thorough flush but on a "refill breath" they only get a 1.5, BUT on subsequent refils they always get a 1.5 and not a constantly dropping po2 (lower on each refill)... This is also acceptable since they could plan the "deco" mix for this (using the lowest value).. If they are inconsistent they can do complete flushes at regular periods to get the loop back to a known value.. the key is the person learns their limits, if you have not done it this way you really don;t know what you are capable of, and therefore you don't know what your options really are.. This also needs to be practiced to remain proficient, not just taught, tried and filed for future use.. What normall happens is at the start people are a bit inconsistent but with a few minutes they get into a rythm and things usually get pretty stable.. I find it easist to do on a rig where the ADV can be fully disabled.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated. Last edited by jradomski : 21st December 2007 at 10:40.
(Online)

21st December 2007, 13:04	#36 (permalink)
jo_c Custom Title Allowed! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Join Date: Jun 2006 Location: Hants, UK Posts: 158	Re: CCR Trimix Simplified by Mel Clark question I don't know if it's just me, but it seems crazy to stay on the loop if I'm having CO2 breakthrough because some of the CO2 will get scrubbed out. Especially when you have perfectly good OC gas sat there. Same as I don't think I'd be running SCR mode on ascent if I had no displays to tell me exactly what PO2 I'm breathing. I have planned bailout gas for the dive.. obviously if you don't take enough bailout for the dive that's a different matter.... Just my opinion.
(Offline)

21st December 2007, 13:26	#37 (permalink)
wondersea New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2006 Location: France - Gerzat (63) - Sanary (83) Posts: 78	Re: CCR Trimix Simplified by Mel Clark question I can tell you, with a Meg, you can fine tune SCR mode even without electronique. Just practice skill and verify then trust you and the Meg. For deco, just make like OC diluent. __________________ Antoine Pannetier DirRebreather member www.DIRRebreather.com
(Online)

21st December 2007, 16:04	#38 (permalink)
silentscuba rEvo CCR Driver Current Rebreather/s: Classic Kiss rEvo Other Rebreather/s: Inspiration Classic rEvo Join Date: Jun 2005 Location: Mill Creek, WA USA Posts: 590	Re: CCR Trimix Simplified by Mel Clark question So, what some of you are saying is that you use to much gas on OC bailout and you don't carry enough so you need to stay on the loop inorder to make things work out OK. What happens if you can't stay on the loop!!! that can happen also. You now have a second problem to solve if you don't have enough bailout with you. I still don't understand why someone would try and figure out a problem by staying on the loop risking their life and then on top of that not have enough bailout in case they can't. We still need to plan for the worst case (carry enough bailout) and hope for the best (maybe staying on the loop) if you can work out the problem. In any case, you should still have enough bailout, and should not take a risk staying on a loop if it is not very clear what is wrong. Just my own opinion . Sounds like a Bail Out CCR would be a good thing!!! __________________ Curt McNamee rEvo CCR Diver KISS CCR Diver www.silentscuba.com
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21st December 2007, 16:28	#39 (permalink)
wondersea New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2006 Location: France - Gerzat (63) - Sanary (83) Posts: 78	Re: CCR Trimix Simplified by Mel Clark question I am talking for me, even if I think I can stay on the loop and OC bailout is the last option, I allways carry enough bailout for the worst case If not, It's fool option and I want to be an old happy CCR diver __________________ Antoine Pannetier DirRebreather member www.DIRRebreather.com
(Online)

21st December 2007, 16:49	#40 (permalink)
curt New Member Current Rebreather/s: Other CCR Dolphin Other Rebreather/s: Not Bought Yet Inspiration Classic Classic Kiss MK 15.X Other CCR Dolphin Join Date: Jul 2006 Location: Rockville, MD USA Posts: 92	Re: CCR Trimix Simplified by Mel Clark question Hi Mel, Thanks for the clarifications, and the great work on getting this book produced. __________________ Curt Harpold US Representative Rebreathers Australia http://rebreathers.com.au/
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