Incident on the surface - mCCR

gerstl_ossi · 26th March 2008, 21:08

Nice to hear averyting went for the best way. Thanks for posting.

Save diving and chears Ossi

**Dave Sutton** · 26th March 2008, 23:10

Well done, and well shared. Green sent.

Bet it's Pure 02 in the loop above 20 feet at all times in the future? Stake your life on it.....

Dave

OceanOpportunity · 27th March 2008, 00:15

Dave...you beat me to it.

But to elaborate.... I am confused by this statement from the original post:

"4) My HUD was working, but being at the surface, my flashing green warning didn't mean anything to me since my set point was 1.0 (unmaintainable directly at the surface)"

A PO2 of 1.0 should be incredibly easy to maintain at the surface, as 100% O2 at 1ATA is 1.0. My practice on mCCR is to calibrate, then dive the unit exclusively with O2 at the surface and down to 20 feet or so, do my S-drill/final bubble check, then commence the dive. At 20 feet, your PO2 is about 1.6ATA. Dont futz with finding your setpoint in the shallows...leave everything rich during the descent, while adding your dil to make up volume, and you will eventually metabolize the O2 down to where it needs to be. Generally speaking, once you begin the descent, you probably wont have to touch your manual O2 til you're on the bottom since you have plenty of O2 in the mix to begin with. Oxygen is a good thing...small blips to 1.6 arent going to hurt anyone.

Glad to hear that the situation was dealt with ok and that everyone is safe.

ML

**kevin stone** · 27th March 2008, 00:15

Thanks for sharing
I had a similar experience last year when helping another diver.
My initial reaction was to help my buddy drew all my attention from my own
falling p02.
I now keep my p02 as high as possible and if it spikes on decent so what!
I just flush a little dil and down it comes and all is good.
But to hedge my bets when I got home from my trip I called Kevin J the next day and bought a Hammer head secondary and installed it on my Sport KISS so now if my p02 gets low the DIVA shakes so hard it scares the shit out of you.

Kevin

PCDiver · 27th March 2008, 04:44

Quote: (Originally Posted by OceanOpportunity)

A PO2 of 1.0 should be incredibly easy to maintain at the surface, as 100% O2 at 1ATA is 1.0.

As far as I know, training agencies don't teach using high PO2 at the surface, which is a real shame. There have been too many incidents (accidents?) with rebreather divers and hypoxia at the surface.

**Dave Sutton** · 27th March 2008, 10:30

Quote: (Originally Posted by PCDiver)

As far as I know, training agencies don't teach using high PO2 at the surface, which is a real shame. There have been too many incidents (accidents?) with rebreather divers and hypoxia at the surface.

Uhh............. I can tell you that if I teach you to dive a mCCR, you'll have pure 02 in the loop *anytime* you are above 6 M. I'd call this "normal" and anything other than that "abnormal". I'd be surprised to find any competent mCCR Intructor (is there any other type?

) teaching otherwise. Heck, you ought to be fully flooding the loop with pure 02 to check the sensors before the dive: Leave the bag that way and go diving.

On an eCCR... the loop should be at MINIMUM at the surface setpoint, assuming a switchable setpoint controller.

Dave

.

PCDiver · 27th March 2008, 10:38

Quote: (Originally Posted by Dave Sutton)

On an eCCR... the loop should be at MINIMUM at the surface setpoint, assuming a switchable setpoint controller.

Why minimum?

**Dave Sutton** · 27th March 2008, 10:48

Quote: (Originally Posted by PCDiver)

Why minimum?

You ideally want the rig settled in "on setpoint" with the controller holding setpoint during your pre-breathe period on the surface to make sure the thing works, and to have sufficient 02 in the loop to deal with a failure of the controller at the moment you jump into the water (IE the old Inspiration "Battery Bounce" scenario) at a phase of the dive where your task loading is high.

Should likely be more than the setpoint as you make your jump, but at minimum, it should be on surface setpoint (0.7 or so) and fully stabilized and holding that setpoint for at least 3 minutes before you dive. I'd be shocked if anyone was teaching it differently.

Dave

.

AM · 27th March 2008, 11:38

Hi - I haven't read the whole thread so apologies if I'm repeating something someone else already said.

I'll go a step further than what the manual training courses teach and say, when you're on the surface, whack your O2 up to 1.00 bar. That way, should there be any issue with delay, user mistake i.e. O2 not switched on etc, you have a little margin of error to play with.

There is no good reason not to be on 100% above 6m, it will do you no harm on a surface swim or waiting to enter water to be on 100%.

Here's an exercise for you - try getting all your gear on and standing on a rocking boat waiting to get in. Don't actually get in though straightaway. Try doing this with your O2 off and watch just how quickly you metabolise the O2 in the loop. When you're breathing hard, that O2 just disappears.
Make sure you turn your O2 on before you get in! Then jack it up to 1.00 bar. 0.70 isn't good enough on a manual rebreather on the surface. This is why it's a safer practice to start from your highest possible O2 position on the surface.

Once underwater you can dump it or trigger ADV to avoid spiking on descent.

The other thing that struck me from your post is that all the stress/rushing resulted because of the people waiting to get in and their comments. I suggest that managing peer pressure is also an issue here. If a similar situation occurs, either ignore them and take as much time as you need or stop what you're doing and start again. Your life is more important than a couple of impatient people with a bad attitude. Can you imagine what would have happened if you did not have any physiological warning and just went to sleep. Those people sure as hell wouldn't have been getting in the water then!

So, next time *anyone* exerts pressure to get into the water or rush the process, politely tell them that you/your buddy are not prepared to rush a pre-dive sequence, which if done wrong, will cost your life. I must admit, I wouldn't be quite so polite...but that's another story

The alternative position to manual CCR on the surface is go OC if waiting for long periods, just make sure you don't switch to hypoxic inboard dil! Having an OC/DSV does make the OC/CCR switch process extremely easy.

Glad you managed to take corrective action. Most mistakes on CCR do seem to happen when the pre-dive sequence is rushed or you become distracted. This is the most dangerous part of any CCR dive.

Regards

AnneMarie

PCDiver · 27th March 2008, 12:32

Quote: (Originally Posted by Dave Sutton)

Should likely be more than the setpoint as you make your jump, but at minimum, it should be on surface setpoint (0.7 or so) and fully stabilized and holding that setpoint for at least 3 minutes before you dive. I'd be shocked if anyone was teaching it differently.

I still fail to see the difference between eCCR and mCCR. If on eCCR you let the controller manage the O2, what would give you a PPO2 around the setpoint, you loose one important alert mechanism, which is the lung volume reduction in case something is not right (oxygen turned off, controller not working). Ofcourse the proper working of the controller needs to be verified, but that is done in the predive check. After the check, a couple of thorough flushes with O2. Then you jump in. The first time dil is added is at 6 meters.

26th March 2008, 21:08	#31 (permalink)
gerstl_ossi Custom Title Allowed! Current Rebreather/s: RB80 / Clone Home Build Other Rebreather/s: Not Bought Yet RB80 / Clone Home Build Join Date: Dec 2006 Location: Italy Posts: 272	Re: Incident on the surface - mCCR Nice to hear averyting went for the best way. Thanks for posting. Save diving and chears Ossi
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26th March 2008, 23:10	#32 (permalink)
Dave Sutton Living on Animal Farm 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: 2,463	Re: Incident on the surface - mCCR Well done, and well shared. Green sent. Bet it's Pure 02 in the loop above 20 feet at all times in the future? Stake your life on it..... Dave __________________ . "All animals are equal, but some animals are more equal than others" Professional Small Boy: Never Successfully Cubicled.
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27th March 2008, 00:15	#33 (permalink)
OceanOpportunity for a world of water Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Other CCR Dolphin Home Build Join Date: Nov 2006 Location: Providence, RI USA Posts: 465	Re: Incident on the surface - mCCR Dave...you beat me to it. But to elaborate.... I am confused by this statement from the original post: "4) My HUD was working, but being at the surface, my flashing green warning didn't mean anything to me since my set point was 1.0 (unmaintainable directly at the surface)" A PO2 of 1.0 should be incredibly easy to maintain at the surface, as 100% O2 at 1ATA is 1.0. My practice on mCCR is to calibrate, then dive the unit exclusively with O2 at the surface and down to 20 feet or so, do my S-drill/final bubble check, then commence the dive. At 20 feet, your PO2 is about 1.6ATA. Dont futz with finding your setpoint in the shallows...leave everything rich during the descent, while adding your dil to make up volume, and you will eventually metabolize the O2 down to where it needs to be. Generally speaking, once you begin the descent, you probably wont have to touch your manual O2 til you're on the bottom since you have plenty of O2 in the mix to begin with. Oxygen is a good thing...small blips to 1.6 arent going to hurt anyone. Glad to hear that the situation was dealt with ok and that everyone is safe. ML __________________ Michael Lombardi Oceans of Opportunity www.oceanopportunity.com Elected Director, Society for Human Performance in Extreme Environments MN'07, The Explorers Club Project Manager, Diving a Dream
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27th March 2008, 00:15	#34 (permalink)
kevin stone Supporting Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: us ct. Posts: 157	Re: Incident on the surface - mCCR Thanks for sharing I had a similar experience last year when helping another diver. My initial reaction was to help my buddy drew all my attention from my own falling p02. I now keep my p02 as high as possible and if it spikes on decent so what! I just flush a little dil and down it comes and all is good. But to hedge my bets when I got home from my trip I called Kevin J the next day and bought a Hammer head secondary and installed it on my Sport KISS so now if my p02 gets low the DIVA shakes so hard it scares the shit out of you. Kevin
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27th March 2008, 04:44	#35 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 885	Re: Incident on the surface - mCCR Quote: (Originally Posted by OceanOpportunity) A PO2 of 1.0 should be incredibly easy to maintain at the surface, as 100% O2 at 1ATA is 1.0. As far as I know, training agencies don't teach using high PO2 at the surface, which is a real shame. There have been too many incidents (accidents?) with rebreather divers and hypoxia at the surface. __________________ >>>>> www.submergeproductions.com dedicated to promoting technical diving >>>>> Check out our dive show video interviews at http://www.submergeproductions.com/A...nterviews.aspx >>>>> Wreck dive videos http://www.submergeproductions.com/A...omthedeep.aspx
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27th March 2008, 10:30	#36 (permalink)
Dave Sutton Living on Animal Farm 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: 2,463	Re: Incident on the surface - mCCR Quote: (Originally Posted by PCDiver) As far as I know, training agencies don't teach using high PO2 at the surface, which is a real shame. There have been too many incidents (accidents?) with rebreather divers and hypoxia at the surface. Uhh............. I can tell you that if I teach you to dive a mCCR, you'll have pure 02 in the loop anytime you are above 6 M. I'd call this "normal" and anything other than that "abnormal". I'd be surprised to find any competent mCCR Intructor (is there any other type? ) teaching otherwise. Heck, you ought to be fully flooding the loop with pure 02 to check the sensors before the dive: Leave the bag that way and go diving. On an eCCR... the loop should be at MINIMUM at the surface setpoint, assuming a switchable setpoint controller. Dave . __________________ . "All animals are equal, but some animals are more equal than others" Professional Small Boy: Never Successfully Cubicled.
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27th March 2008, 10:38	#37 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 885	Re: Incident on the surface - mCCR Quote: (Originally Posted by Dave Sutton) On an eCCR... the loop should be at MINIMUM at the surface setpoint, assuming a switchable setpoint controller. Why minimum? __________________ >>>>> www.submergeproductions.com dedicated to promoting technical diving >>>>> Check out our dive show video interviews at http://www.submergeproductions.com/A...nterviews.aspx >>>>> Wreck dive videos http://www.submergeproductions.com/A...omthedeep.aspx
(Online)

27th March 2008, 10:48	#38 (permalink)
Dave Sutton Living on Animal Farm 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: 2,463	Re: Incident on the surface - mCCR Quote: (Originally Posted by PCDiver) Why minimum? You ideally want the rig settled in "on setpoint" with the controller holding setpoint during your pre-breathe period on the surface to make sure the thing works, and to have sufficient 02 in the loop to deal with a failure of the controller at the moment you jump into the water (IE the old Inspiration "Battery Bounce" scenario) at a phase of the dive where your task loading is high. Should likely be more than the setpoint as you make your jump, but at minimum, it should be on surface setpoint (0.7 or so) and fully stabilized and holding that setpoint for at least 3 minutes before you dive. I'd be shocked if anyone was teaching it differently. Dave . __________________ . "All animals are equal, but some animals are more equal than others" Professional Small Boy: Never Successfully Cubicled.
(Offline)

27th March 2008, 11:38	#39 (permalink)
AM Gone diving!! Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Inside my cage Posts: 483	Re: Incident on the surface - mCCR Hi - I haven't read the whole thread so apologies if I'm repeating something someone else already said. I'll go a step further than what the manual training courses teach and say, when you're on the surface, whack your O2 up to 1.00 bar. That way, should there be any issue with delay, user mistake i.e. O2 not switched on etc, you have a little margin of error to play with. There is no good reason not to be on 100% above 6m, it will do you no harm on a surface swim or waiting to enter water to be on 100%. Here's an exercise for you - try getting all your gear on and standing on a rocking boat waiting to get in. Don't actually get in though straightaway. Try doing this with your O2 off and watch just how quickly you metabolise the O2 in the loop. When you're breathing hard, that O2 just disappears. Make sure you turn your O2 on before you get in! Then jack it up to 1.00 bar. 0.70 isn't good enough on a manual rebreather on the surface. This is why it's a safer practice to start from your highest possible O2 position on the surface. Once underwater you can dump it or trigger ADV to avoid spiking on descent. The other thing that struck me from your post is that all the stress/rushing resulted because of the people waiting to get in and their comments. I suggest that managing peer pressure is also an issue here. If a similar situation occurs, either ignore them and take as much time as you need or stop what you're doing and start again. Your life is more important than a couple of impatient people with a bad attitude. Can you imagine what would have happened if you did not have any physiological warning and just went to sleep. Those people sure as hell wouldn't have been getting in the water then! So, next time anyone exerts pressure to get into the water or rush the process, politely tell them that you/your buddy are not prepared to rush a pre-dive sequence, which if done wrong, will cost your life. I must admit, I wouldn't be quite so polite...but that's another story The alternative position to manual CCR on the surface is go OC if waiting for long periods, just make sure you don't switch to hypoxic inboard dil! Having an OC/DSV does make the OC/CCR switch process extremely easy. Glad you managed to take corrective action. Most mistakes on CCR do seem to happen when the pre-dive sequence is rushed or you become distracted. This is the most dangerous part of any CCR dive. Regards AnneMarie __________________ Attitude keeps you alive Last edited by AM : 27th March 2008 at 11:47.
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27th March 2008, 12:32	#40 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 885	Re: Incident on the surface - mCCR Quote: (Originally Posted by Dave Sutton) Should likely be more than the setpoint as you make your jump, but at minimum, it should be on surface setpoint (0.7 or so) and fully stabilized and holding that setpoint for at least 3 minutes before you dive. I'd be shocked if anyone was teaching it differently. I still fail to see the difference between eCCR and mCCR. If on eCCR you let the controller manage the O2, what would give you a PPO2 around the setpoint, you loose one important alert mechanism, which is the lung volume reduction in case something is not right (oxygen turned off, controller not working). Ofcourse the proper working of the controller needs to be verified, but that is done in the predive check. After the check, a couple of thorough flushes with O2. Then you jump in. The first time dil is added is at 6 meters. __________________ >>>>> www.submergeproductions.com dedicated to promoting technical diving >>>>> Check out our dive show video interviews at http://www.submergeproductions.com/A...nterviews.aspx >>>>> Wreck dive videos http://www.submergeproductions.com/A...omthedeep.aspx
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