Incident on the surface - mCCR

Mark Chase · 26th March 2008, 15:46

The Hammer Head DIVA vibrating HUD has my vote for this situation. On the surface all HUD's are hard to see. Kevin and the Borris/Sentinal boys have got it right IMHO.

The only place i dont like being on a MCCR is on the surface.

Well done for surviving and posting this.

ATB

Mark

Scubascooby · 26th March 2008, 16:02

Good to hear that you survived such a low ppO2.

On the surface I never let my ppO2 drop below 0.7-ish. So far I've not had
to do any hard work on the surface but in an emergency my plan has been to switch to OC either on the KISS BOV or bail-out tank.

When entering the water I still keep it quite high, the swim to the shot in a slight current and swell can be an exertion after the faff of kitting up on a boat. Then I vent a mouthful from the loop to quickly get out of the surface slop and the rope tangle under the buoy. 2m down, a bit of dil gets pulled in via the ADV and prevents any O2 spike.

ps. Don't be too hard on your daughter. She probably saw you dealing well
with the situation and decided to stay out of the way. Had I been in that
situation I would have lurked alongside to assist if needed.

mempilot · 26th March 2008, 16:41

Thank you for sharing. More food for thought while I sit here couch diving. Some green your way.

.09 PPO2! That is way freaking low. I'm glad you are alive brother. I'm not familiar with the where in the loop the KISS takes it's readings, but anyway you slice it, you where lucky to be able to diagnose it and react. Like you say, maybe your cardiovascular health played a role. From chamber rides, I know I would never be able to respond at a PO2 that low. That is why I like the alpha floor protection of .2 on my Meg.

I like the idea mentioned in an above post about a hybrid m/eCCR with an orfice and solenoid. I sometimes fly my Meg manually, and enjoy the sense of security on the low end. Doesn't Gorilla Diving Products make a constanct flow device that can be rigged to a p-port on an eCCR? I think my buddy bought a used standard Meg that had been equipped with one, but opted not to buy the add-on.

Anyway, glad to hear all ended up well and the only damage was your friends bruised ego.

Eric

**Gill Envy** · 26th March 2008, 16:47

Adrian, it's not a stupid question at all. I had a very narrow understanding of mCCR's until I owned and dove one. You are probably referring to the mass flow orifice which can't be adjusted on the fly (It's determined by the IP in the first stage- which is adjusted pre dive), it's adjusted to below the minimum metabolic rate for the diver at rest with the understanding that manual top off will be necessary during regular dive mode. While it adds a buffer in general, it does not safeguard against a sudden and dramatic increase in metabolic rate as would be common in a heightened state of anxiety and physical exertion typical of things like a rescue or swimming heavy against a current... in these scenarios an increase in o2 injection rate is required. Luckily training and experience make this an ever more intuitive process.

A needle valve may have given this diver the option to go longer hands free but until I get my hands on one and get some hours on it, i'll hold off from speculation.

Since I added a HUD to my copis that shows real time po2 on all three cells simultaneously, I never rely on any kind of alarm to tell me po2, i'm directly reading it pretty much continuously. Over time I have learned to bump up the manual injection rate any time I either ascend or increase my work load. If I'm doing something like filming, or photographing I'll bump up the po2 a bit and be extra anal about monitoring the HUD as it drops while on task.

g

Quote: (Originally Posted by sfldiver)

I'm glad it all worked out in the end and it never escalated to a more serious issue, but it sounds like it got very very close to that point.

Thanks for sharing!

I apologize in advance for the ignorance of my question, because I am not familiar with your rebreather, but isn't there some type of backup system to assist you in avoiding that scenario?

I often hear how manual rebreathers are the only way to go, because they're so much safer; however, in this scenario, my electronic rebreather (Dive Rite Optima) would have notified me with the vibrating mouthpiece and automatically fired the selanoid and kept my loop PO2 within the life supporting zone. Does your rebreather have any similar features?

Again, glad you're here to tell the story and appreciative of the fact that you decided to post and allow us to learn from your experience!

Adrian

**Gill Envy** · 26th March 2008, 16:53

Quote: (Originally Posted by brockbr)

I've been asked about my HUD, so I wanted to respond to that:

I do have a C2R HUD on my Classic KISS. This HUD uses 2 LED's. Green for pO2, and red for Decompression.

Green Slow Flash = Low pO2 (.2 or more under set point)
Green Solid - Within .2 of set point (high or low)
Green Fast Flash = High pO2 (.2 or more over set point)

Red relates only to deco and stops.

It seems like having a set point integrated into the HUD, on an mCCR in particular, leaves one very vulnerable in the shallows to just such a scenario and is just a bad design idea for mCCR's altogether.

If it sounds like i'm bashing your kit, please don't take it that way, just trying to learn and share ideas.

g

Dutchy · 26th March 2008, 17:09

Quote: (Originally Posted by Gill Envy)

It seems like having a set point integrated into the HUD, on an mCCR in particular, leaves one very vulnerable in the shallows to just such a scenario and is just a bad design idea for mCCR's altogether.

If it sounds like i'm bashing your kit, please don't take it that way, just trying to learn and share ideas.

g

It is never a single thing. If the HUD had had a bright red flash for anything under .4 there would have been a trigger for injecting. (there are leds that you CAN see in bright sunlight)

My lesson from a scare at .14 is to operate on O2 above 6m. Once on O2 if I can't breath then I have a few options:
a) inject O2 (not possible when climbing stairs)
b) go OC on BOV (ditto)
c) Let go of the loop (not ideal as one could fall off the stairs with an immeate flood as result result in a potential boyancy issue)

Andy Del · 26th March 2008, 18:44

Quote: (Originally Posted by brockbr)

Prior to putting my head under, I would flush with Dil so I didn't enter the water with a high pO2 in my loop that I can't burn off fast enough, thus spiking my pO2 on decent. To illustrate this, if I started with a true .5 or higher, an immediate decent to depth will easily spike the pO2.

Also, in getting ready to do CCR Trimix, I've read this step is especially import so that the gas mix is correct in your loop, and not some weird mix of air + dil, which could make your N2 higher then your Dil.

Good to read you dodged the bullet!

It's always rather sobering to realise things went awry. However, I would personally question your approach to dil flushes on the surface, as I too have had one 'low PO2 on the surface' incident that made certain I changed my practices.

It is now:

Get onto the loop and do a dil flush (with some level of efficiency on hypoxic mixes)
Exhale all gas from the loop
Manually inject O2 so you geta high PO2, 0.7 - 0.9
Complete pre-breathe
Jump in the drink, monitor for a high PO2, particularly during/after exertion
Use ADV on descent, no dil flush before (you already did this)

This has proven to be a simple, thus-far fool-proof* way to ensure you have a good loop to start with WRT diluent content, a high PO2 to start the dive with and less chance of going hypoxic quickly on the surface. It works on air dil on 5m dives and mix dives to 120m.

*in the case of this fool at least.

Quote:

HUDs are great tools, but to paraphrase Dave Sutton who recently said "given all the right tools, the diver can still kill themselves" - Vigilance is the only way.

akscubainst · 26th March 2008, 18:57

Glad you are ok and this can be chalked up to lesson(s) learned.

Rebreather issues aside, besides yelling at your daughter, have you assessed your own responsibility as a buddy?

Not being there, but reading your story, it sounds as if you and your daughter abandoned your 3rd buddy who felt rushed to catch up and didn't properly prepare himself for the dive. Then to jump in the water half dressed, why didn't he just step aside? Hopefully he learned something too.

Couldn't all 3 of you have waited for the groups to pass, assisted each other to get dressed then proceeded to the water together?

Just my armchair quarterbacking - again, I'm glad you're safe!

Dave

brockbr · 26th March 2008, 19:27

Quote: (Originally Posted by akscubainst)

Glad you are ok and this can be chalked up to lesson(s) learned.

Rebreather issues aside, besides yelling at your daughter, have you assessed your own responsibility as a buddy?

Not being there, but reading your story, it sounds as if you and your daughter abandoned your 3rd buddy who felt rushed to catch up and didn't properly prepare himself for the dive. Then to jump in the water half dressed, why didn't he just step aside? Hopefully he learned something too.

Couldn't all 3 of you have waited for the groups to pass, assisted each other to get dressed then proceeded to the water together?

Just my armchair quarterbacking - again, I'm glad you're safe!

Dave

Given the entry area, I was as close as practicable for the very reason to assist my buddy (there were also people queueing to exit, so I was as close as I thought I could get without causing a problem).

All of us finishing on the step wasn't possible, since there is only room for one person, group or no group.

I'd also like to point out (in my defense of course

) that my buddy's situation didn't go unmonitored for an instant - I saw him jump into the water, I saw him roll, I saw him drop stuff etc - I am a good buddy

I just needed a buddy to watch my pO2

Still, a very good point that buddies should stick together.

PCDiver · 26th March 2008, 20:58

I'm not diving mCCR but eCCR, but the rule I use applies to both. The rule is simple: at the surface before the dive, the loop should mostly contain O2 and as little diluent as possible. Why?

1. The shrinking loop volume will alert you if you forget to add O2 or if your eCCR controller isn't working. This will happen before you pass out because of hypoxia. Not being able to breath is a very distinctive and impossible to miss signal.
2. You can easily test your cells for being current limited. Just go down to 4 to 6 meters and the cells should go above 1.3. Deeper than six you just add diluent.

Have some green for posting this story.

Peter

EDIT <sorry for repeating what Andi said, I missed it completely. But he is absolutely right!>

26th March 2008, 15:46	#21 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,564	Re: Incident on the surface - mCCR The Hammer Head DIVA vibrating HUD has my vote for this situation. On the surface all HUD's are hard to see. Kevin and the Borris/Sentinal boys have got it right IMHO. The only place i dont like being on a MCCR is on the surface. Well done for surviving and posting this. ATB Mark __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
(Offline)

26th March 2008, 16:02	#22 (permalink)
Scubascooby Better Off Out of the EU Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Nov 2005 Location: Great Britain Posts: 367	Re: Incident on the surface - mCCR Good to hear that you survived such a low ppO2. On the surface I never let my ppO2 drop below 0.7-ish. So far I've not had to do any hard work on the surface but in an emergency my plan has been to switch to OC either on the KISS BOV or bail-out tank. When entering the water I still keep it quite high, the swim to the shot in a slight current and swell can be an exertion after the faff of kitting up on a boat. Then I vent a mouthful from the loop to quickly get out of the surface slop and the rope tangle under the buoy. 2m down, a bit of dil gets pulled in via the ADV and prevents any O2 spike. ps. Don't be too hard on your daughter. She probably saw you dealing well with the situation and decided to stay out of the way. Had I been in that situation I would have lurked alongside to assist if needed. __________________ "dove" is NOT the past tense of "dive" Better off OUT of the EU !
(Offline)

26th March 2008, 16:41	#23 (permalink)
mempilot What is this..terrafirma? Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 1,269	Re: Incident on the surface - mCCR Thank you for sharing. More food for thought while I sit here couch diving. Some green your way. .09 PPO2! That is way freaking low. I'm glad you are alive brother. I'm not familiar with the where in the loop the KISS takes it's readings, but anyway you slice it, you where lucky to be able to diagnose it and react. Like you say, maybe your cardiovascular health played a role. From chamber rides, I know I would never be able to respond at a PO2 that low. That is why I like the alpha floor protection of .2 on my Meg. I like the idea mentioned in an above post about a hybrid m/eCCR with an orfice and solenoid. I sometimes fly my Meg manually, and enjoy the sense of security on the low end. Doesn't Gorilla Diving Products make a constanct flow device that can be rigged to a p-port on an eCCR? I think my buddy bought a used standard Meg that had been equipped with one, but opted not to buy the add-on. Anyway, glad to hear all ended up well and the only damage was your friends bruised ego. Eric __________________ MEM "Da Pilot" Black holes are where God divided by zero. "If at first you don't succeed, don't dive silent." "Would you mind not shooting at the thermo-nuclear weapons." ~ Vic Deakins "Donkey's kill more people annually than plane crashes."
(Offline)

26th March 2008, 16:47	#24 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,302	Re: Incident on the surface - mCCR Adrian, it's not a stupid question at all. I had a very narrow understanding of mCCR's until I owned and dove one. You are probably referring to the mass flow orifice which can't be adjusted on the fly (It's determined by the IP in the first stage- which is adjusted pre dive), it's adjusted to below the minimum metabolic rate for the diver at rest with the understanding that manual top off will be necessary during regular dive mode. While it adds a buffer in general, it does not safeguard against a sudden and dramatic increase in metabolic rate as would be common in a heightened state of anxiety and physical exertion typical of things like a rescue or swimming heavy against a current... in these scenarios an increase in o2 injection rate is required. Luckily training and experience make this an ever more intuitive process. A needle valve may have given this diver the option to go longer hands free but until I get my hands on one and get some hours on it, i'll hold off from speculation. Since I added a HUD to my copis that shows real time po2 on all three cells simultaneously, I never rely on any kind of alarm to tell me po2, i'm directly reading it pretty much continuously. Over time I have learned to bump up the manual injection rate any time I either ascend or increase my work load. If I'm doing something like filming, or photographing I'll bump up the po2 a bit and be extra anal about monitoring the HUD as it drops while on task. g Quote: (Originally Posted by sfldiver) I'm glad it all worked out in the end and it never escalated to a more serious issue, but it sounds like it got very very close to that point. Thanks for sharing! I apologize in advance for the ignorance of my question, because I am not familiar with your rebreather, but isn't there some type of backup system to assist you in avoiding that scenario? I often hear how manual rebreathers are the only way to go, because they're so much safer; however, in this scenario, my electronic rebreather (Dive Rite Optima) would have notified me with the vibrating mouthpiece and automatically fired the selanoid and kept my loop PO2 within the life supporting zone. Does your rebreather have any similar features? Again, glad you're here to tell the story and appreciative of the fact that you decided to post and allow us to learn from your experience! Adrian __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
(Offline)

26th March 2008, 16:53	#25 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,302	Re: Incident on the surface - mCCR Quote: (Originally Posted by brockbr) I've been asked about my HUD, so I wanted to respond to that: I do have a C2R HUD on my Classic KISS. This HUD uses 2 LED's. Green for pO2, and red for Decompression. Green Slow Flash = Low pO2 (.2 or more under set point) Green Solid - Within .2 of set point (high or low) Green Fast Flash = High pO2 (.2 or more over set point) Red relates only to deco and stops. It seems like having a set point integrated into the HUD, on an mCCR in particular, leaves one very vulnerable in the shallows to just such a scenario and is just a bad design idea for mCCR's altogether. If it sounds like i'm bashing your kit, please don't take it that way, just trying to learn and share ideas. g __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
(Offline)

26th March 2008, 17:09	#26 (permalink)
Dutchy SK#007 Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: Apr 2006 Location: Nieuwegein (The Netherlands) Posts: 730	Re: Incident on the surface - mCCR Quote: (Originally Posted by Gill Envy) It seems like having a set point integrated into the HUD, on an mCCR in particular, leaves one very vulnerable in the shallows to just such a scenario and is just a bad design idea for mCCR's altogether. If it sounds like i'm bashing your kit, please don't take it that way, just trying to learn and share ideas. g It is never a single thing. If the HUD had had a bright red flash for anything under .4 there would have been a trigger for injecting. (there are leds that you CAN see in bright sunlight) My lesson from a scare at .14 is to operate on O2 above 6m. Once on O2 if I can't breath then I have a few options: a) inject O2 (not possible when climbing stairs) b) go OC on BOV (ditto) c) Let go of the loop (not ideal as one could fall off the stairs with an immeate flood as result result in a potential boyancy issue) __________________ = This post is environmentally friendly. It is composed of 100% recycled electrons only. = SK #007
(Online)

26th March 2008, 18:44	#27 (permalink)
Andy Del Classic KISSer Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: Australia, Sunny Sydney Posts: 413	Re: Incident on the surface - mCCR Quote: (Originally Posted by brockbr) Prior to putting my head under, I would flush with Dil so I didn't enter the water with a high pO2 in my loop that I can't burn off fast enough, thus spiking my pO2 on decent. To illustrate this, if I started with a true .5 or higher, an immediate decent to depth will easily spike the pO2. Also, in getting ready to do CCR Trimix, I've read this step is especially import so that the gas mix is correct in your loop, and not some weird mix of air + dil, which could make your N2 higher then your Dil. Good to read you dodged the bullet! It's always rather sobering to realise things went awry. However, I would personally question your approach to dil flushes on the surface, as I too have had one 'low PO2 on the surface' incident that made certain I changed my practices. It is now: Get onto the loop and do a dil flush (with some level of efficiency on hypoxic mixes) Exhale all gas from the loop Manually inject O2 so you geta high PO2, 0.7 - 0.9 Complete pre-breathe Jump in the drink, monitor for a high PO2, particularly during/after exertion Use ADV on descent, no dil flush before (you already did this) This has proven to be a simple, thus-far fool-proof* way to ensure you have a good loop to start with WRT diluent content, a high PO2 to start the dive with and less chance of going hypoxic quickly on the surface. It works on air dil on 5m dives and mix dives to 120m. in the case of this fool at least. Quote:* HUDs are great tools, but to paraphrase Dave Sutton who recently said "given all the right tools, the diver can still kill themselves" - Vigilance is the only way. __________________ Yellow - the colour of greatness!
(Offline)

26th March 2008, 18:57	#28 (permalink)
akscubainst It's cold here! Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: May 2005 Location: Juneau, Alaska Posts: 64	Re: Incident on the surface - mCCR Glad you are ok and this can be chalked up to lesson(s) learned. Rebreather issues aside, besides yelling at your daughter, have you assessed your own responsibility as a buddy? Not being there, but reading your story, it sounds as if you and your daughter abandoned your 3rd buddy who felt rushed to catch up and didn't properly prepare himself for the dive. Then to jump in the water half dressed, why didn't he just step aside? Hopefully he learned something too. Couldn't all 3 of you have waited for the groups to pass, assisted each other to get dressed then proceeded to the water together? Just my armchair quarterbacking - again, I'm glad you're safe! Dave __________________ --------------------------------------- Dave Mitchell Classic KISS #200 Juneau, Alaska
(Offline)

26th March 2008, 19:27	#29 (permalink)
brockbr Train Wrecked ;) Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Dec 2007 Location: Alabaster, AL Posts: 224	Re: Incident on the surface - mCCR Quote: (Originally Posted by akscubainst) Glad you are ok and this can be chalked up to lesson(s) learned. Rebreather issues aside, besides yelling at your daughter, have you assessed your own responsibility as a buddy? Not being there, but reading your story, it sounds as if you and your daughter abandoned your 3rd buddy who felt rushed to catch up and didn't properly prepare himself for the dive. Then to jump in the water half dressed, why didn't he just step aside? Hopefully he learned something too. Couldn't all 3 of you have waited for the groups to pass, assisted each other to get dressed then proceeded to the water together? Just my armchair quarterbacking - again, I'm glad you're safe! Dave Given the entry area, I was as close as practicable for the very reason to assist my buddy (there were also people queueing to exit, so I was as close as I thought I could get without causing a problem). All of us finishing on the step wasn't possible, since there is only room for one person, group or no group. I'd also like to point out (in my defense of course ) that my buddy's situation didn't go unmonitored for an instant - I saw him jump into the water, I saw him roll, I saw him drop stuff etc - I am a good buddy I just needed a buddy to watch my pO2 Still, a very good point that buddies should stick together. Last edited by brockbr : 26th March 2008 at 19:32.
(Offline)

26th March 2008, 20:58	#30 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 939	Re: Incident on the surface - mCCR I'm not diving mCCR but eCCR, but the rule I use applies to both. The rule is simple: at the surface before the dive, the loop should mostly contain O2 and as little diluent as possible. Why? 1. The shrinking loop volume will alert you if you forget to add O2 or if your eCCR controller isn't working. This will happen before you pass out because of hypoxia. Not being able to breath is a very distinctive and impossible to miss signal. 2. You can easily test your cells for being current limited. Just go down to 4 to 6 meters and the cells should go above 1.3. Deeper than six you just add diluent. Have some green for posting this story. Peter EDIT <sorry for repeating what Andi said, I missed it completely. But he is absolutely right!> __________________ >>>>> 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 Last edited by PCDiver : 26th March 2008 at 21:02.
(Online)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode