YBOD in SCR with Deco mix

Pierre Farrugia · 22nd July 2006, 18:37

Hello,

I am not sure if I did this in my course! I know and practise how to use Insp. as an Oxygen rebreather! Can someone here explaine to me how can I use my Insp in SCR with deco mix of 70%! Does 4th cell reading be good.

I remember something about first flush rebreather with eg. 70% ,use for 3 breaths and then flush out from nose! Is this all ? If using a VR3 how can I calculate this, in terms of deco ? Do you have to flush with new gas every deco stop? Ascent on OC , due to dec. in PpO2?

**wedivebc** · 22nd July 2006, 20:21

Quote: (Originally Posted by Pierre Farrugia)

Hello,

I am not sure if I did this in my course! I know and practise how to use Insp. as an Oxygen rebreather! Can someone here explaine to me how can I use my Insp in SCR with deco mix of 70%! Does 4th cell reading be good.

I remember something about first flush rebreather with eg. 70% ,use for 3 breaths and then flush out from nose! Is this all ? If using a VR3 how can I calculate this, in terms of deco ? Do you have to flush with new gas every deco stop? Ascent on OC , due to dec. in PpO2?

Not sure why you would want to but if you have a VR3 (or another computer) tied into the 4th cell then yes it should track your deco however the resultant fiO2 will be something less than 70% and may not be your best gas choice for deco. If you are doing this for bailout then you would have to rely on your computer to get you back as you could not cut tables on a mix you could not accurately predict.

Pierre Farrugia · 22nd July 2006, 20:40

Quote: (Originally Posted by wedivebc)

Not sure why you would want to but if you have a VR3 (or another computer) tied into the 4th cell then yes it should track your deco however the resultant fiO2 will be something less than 70% and may not be your best gas choice for deco. If you are doing this for bailout then you would have to rely on your computer to get you back as you could not cut tables on a mix you could not accurately predict.

About the procedure described above is it correct ? And yes this will be only for bailout!

**wedivebc** · 22nd July 2006, 21:53

Quote: (Originally Posted by Pierre Farrugia)

About the procedure described above is it correct ? And yes this will be only for bailout!

The procedure you describe was taught to me on my inspiration course and I had to dive in SCR mode for about 15 minutes on my course. I have never used that method since and my meg instructor (Leon) was opposed to using that at all.

Pierre Farrugia · 25th July 2006, 05:55

Any more help on this topic, please

jhaaja · 25th July 2006, 06:46

Quote: (Originally Posted by Pierre Farrugia)

Hello,

I am not sure if I did this in my course! I know and practise how to use Insp. as an Oxygen rebreather! Can someone here explaine to me how can I use my Insp in SCR with deco mix of 70%! Does 4th cell reading be good.

I remember something about first flush rebreather with eg. 70% ,use for 3 breaths and then flush out from nose! Is this all ? If using a VR3 how can I calculate this, in terms of deco ? Do you have to flush with new gas every deco stop? Ascent on OC , due to dec. in PpO2?

You use it as normally would do in SCR. When in constant depth maybe exhale every fifth breath through your nose. When accending maybe every third, because the ppO2 is droppin because the ambient pressure is dropping. If you need to ascent really fast then it would be wise to use OC on the ascent.

VR3 4th cell will calculate the deco correctly because it sees the drop in ppO2 if you have the 4th cell on and working. You don`t have to do any special flushes. The flush happens when you exhale the loop content through your nose and take fresh gas through the ADV.

Hope this helps!

I have only done scr on the course, never had to do a real bailout with it.

JH

Pierre Farrugia · 26th July 2006, 22:56

Hello,

To what you switch your VR3 as diluent 70% or air ?

jhaaja · 27th July 2006, 05:50

Quote: (Originally Posted by Pierre Farrugia)

Hello,

To what you switch your VR3 as diluent 70% or air ?

It should be on 70%.

JH

22nd July 2006, 18:37	#1 (permalink)
Pierre Farrugia Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Malta Posts: 636	YBOD in SCR with Deco mix Hello, I am not sure if I did this in my course! I know and practise how to use Insp. as an Oxygen rebreather! Can someone here explaine to me how can I use my Insp in SCR with deco mix of 70%! Does 4th cell reading be good. I remember something about first flush rebreather with eg. 70% ,use for 3 breaths and then flush out from nose! Is this all ? If using a VR3 how can I calculate this, in terms of deco ? Do you have to flush with new gas every deco stop? Ascent on OC , due to dec. in PpO2? __________________ Pierre Farrugia My wife told me " If you don't quit diving I'm going to leave you" My reply " God, I'll miss you" www.atlam.org www.divemed.com
(Offline)

22nd July 2006, 20:21	#2 (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: 1,493	Re: YBOD in SCR with Deco mix Quote: (Originally Posted by Pierre Farrugia) Hello, I am not sure if I did this in my course! I know and practise how to use Insp. as an Oxygen rebreather! Can someone here explaine to me how can I use my Insp in SCR with deco mix of 70%! Does 4th cell reading be good. I remember something about first flush rebreather with eg. 70% ,use for 3 breaths and then flush out from nose! Is this all ? If using a VR3 how can I calculate this, in terms of deco ? Do you have to flush with new gas every deco stop? Ascent on OC , due to dec. in PpO2? Not sure why you would want to but if you have a VR3 (or another computer) tied into the 4th cell then yes it should track your deco however the resultant fiO2 will be something less than 70% and may not be your best gas choice for deco. If you are doing this for bailout then you would have to rely on your computer to get you back as you could not cut tables on a mix you could not accurately predict. __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
(Offline)

22nd July 2006, 20:40	#3 (permalink)
Pierre Farrugia Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Malta Posts: 636	Re: YBOD in SCR with Deco mix Quote: (Originally Posted by wedivebc) Not sure why you would want to but if you have a VR3 (or another computer) tied into the 4th cell then yes it should track your deco however the resultant fiO2 will be something less than 70% and may not be your best gas choice for deco. If you are doing this for bailout then you would have to rely on your computer to get you back as you could not cut tables on a mix you could not accurately predict. About the procedure described above is it correct ? And yes this will be only for bailout! __________________ Pierre Farrugia My wife told me " If you don't quit diving I'm going to leave you" My reply " God, I'll miss you" www.atlam.org www.divemed.com
(Offline)

22nd July 2006, 21:53	#4 (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: 1,493	Re: YBOD in SCR with Deco mix Quote: (Originally Posted by Pierre Farrugia) About the procedure described above is it correct ? And yes this will be only for bailout! The procedure you describe was taught to me on my inspiration course and I had to dive in SCR mode for about 15 minutes on my course. I have never used that method since and my meg instructor (Leon) was opposed to using that at all. __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
(Offline)

25th July 2006, 05:55	#5 (permalink)
Pierre Farrugia Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Malta Posts: 636	Re: YBOD in SCR with Deco mix Any more help on this topic, please __________________ Pierre Farrugia My wife told me " If you don't quit diving I'm going to leave you" My reply " God, I'll miss you" www.atlam.org www.divemed.com
(Offline)

25th July 2006, 06:46	#6 (permalink)
jhaaja Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Mar 2005 Location: Finland Posts: 885	Re: YBOD in SCR with Deco mix Quote: (Originally Posted by Pierre Farrugia) Hello, I am not sure if I did this in my course! I know and practise how to use Insp. as an Oxygen rebreather! Can someone here explaine to me how can I use my Insp in SCR with deco mix of 70%! Does 4th cell reading be good. I remember something about first flush rebreather with eg. 70% ,use for 3 breaths and then flush out from nose! Is this all ? If using a VR3 how can I calculate this, in terms of deco ? Do you have to flush with new gas every deco stop? Ascent on OC , due to dec. in PpO2? You use it as normally would do in SCR. When in constant depth maybe exhale every fifth breath through your nose. When accending maybe every third, because the ppO2 is droppin because the ambient pressure is dropping. If you need to ascent really fast then it would be wise to use OC on the ascent. VR3 4th cell will calculate the deco correctly because it sees the drop in ppO2 if you have the 4th cell on and working. You don`t have to do any special flushes. The flush happens when you exhale the loop content through your nose and take fresh gas through the ADV. Hope this helps! I have only done scr on the course, never had to do a real bailout with it. JH
(Offline)

26th July 2006, 22:56	#7 (permalink)
Pierre Farrugia Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Malta Posts: 636	Re: YBOD in SCR with Deco mix Hello, To what you switch your VR3 as diluent 70% or air ? __________________ Pierre Farrugia My wife told me " If you don't quit diving I'm going to leave you" My reply " God, I'll miss you" www.atlam.org www.divemed.com
(Offline)

27th July 2006, 05:50	#8 (permalink)
jhaaja Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Mar 2005 Location: Finland Posts: 885	Re: YBOD in SCR with Deco mix Quote: (Originally Posted by Pierre Farrugia) Hello, To what you switch your VR3 as diluent 70% or air ? It should be on 70%. JH
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