Is a BOW fast enough to save a life?

depth · 6th June 2007, 09:24

Hi RW

For some time now, I have enjoyed reading the many posts regarding many different subjects on RW. Especially the forum describing accidents and incidents has caught my attention, because i belive that lessons learned from others is priceless information.

During my Meg course, my instructor Rasmus Lauritsen from Nordtechdiving.dk (very recomendable instructor), stressed that bailout to OC should be performed very fast if something feels wrong during a dive.

When reading the posts from Rebreather divers involved in O2 or CO2 problems, they barely have time to think "bailout" before passing out.

If I suddently feel that something is wrong, my thoughts on OC bailout are:

- There is NO WAY I have time to reach down for my OC bailout second stage and switch
- There is little chance I have time to reach up for a BOW and turn a handle

Are these assumptions wrong?

Currently I am diving my Meg standard, but I am considering buying a BOW in the near future.

Safe diving....

Rebreatherlab · 6th June 2007, 10:24

As with most things this is also relative to what the problem is and how long it takes you to "feel" something is wrong. If you carry a snd stage on a bungee and dive with the bail valve open it should not take long to get a fresh breath of OC. Still a good quality BOV would cut the time further.
Who can say it this is fast enough? Good question, but at the moment there are no faster alternatives.

I use my BOV for standard DIL additions during the dive and hope that as the motor skill of operating the BOV gets so hammered in that it will further reduce the respond time in a bail scenario.

For 950 USD you can have our high performance BOV that is the most compact out there. It also uses flapper valves made for rebreathers, not standard 2nd stage exhaust valves like you have in your standard Meg DSV. This reduces WOB. This BOV will fit your Meg hoses out of the box and you can swap the mouth piece plate for another to fit a Draeger Panorama fullface mask. This would at least prevent drowning if you dont turn the barrel quick enough. The BOV mechanism comes from a balanced Scubapro S600 regulator and provides easy breathing also at depth.

Please PM or email if you are interested.

All the best,

Andy
REBREATHER LAB

Quote: (Originally Posted by depth)

Hi RW

For some time now, I have enjoyed reading the many posts regarding many different subjects on RW. Especially the forum describing accidents and incidents has caught my attention, because i belive that lessons learned from others is priceless information.

During my Meg course, my instructor Rasmus Lauritsen from Nordtechdiving.dk (very recomendable instructor), stressed that bailout to OC should be performed very fast if something feels wrong during a dive.

When reading the posts from Rebreather divers involved in O2 or CO2 problems, they barely have time to think "bailout" before passing out.

If I suddently feel that something is wrong, my thoughts on OC bailout are:

- There is NO WAY I have time to reach down for my OC bailout second stage and switch
- There is little chance I have time to reach up for a BOW and turn a handle

Are these assumptions wrong?

Currently I am diving my Meg standard, but I am considering buying a BOW in the near future.

Safe diving....

Mark Chase · 6th June 2007, 10:30

Use a BOV and a gag to keep it in then its your buddies job to turn the knob. Or alternativly use a full face mask.

ATB

Mark Chase

**nigelh** · 6th June 2007, 10:45

Quote: (Originally Posted by depth)

During my Meg course, my instructor Rasmus Lauritsen from Nordtechdiving.dk (very recomendable instructor), stressed that bailout to OC should be performed very fast if something feels wrong during a dive.

When reading the posts from Rebreather divers involved in O2 or CO2 problems, they barely have time to think "bailout" before passing out.

Huh?
If you're watching the shop oxygen problems shouldn't sneak up on you.

CO2 is more of a worry as deep it can apparently start with unconsciousness as the first major sign but the usual complaint shallower is that you can't do anything that stops your hyperventilating breathing. The hope with a BOV is that you can just snap it over and try it on the 'sense of unease' that tends to precede this sort of thing and realise that everything suddenly got better. It isn't a magic cure all but a quicker, easier tool than swapping regs.

Gilles · 6th June 2007, 10:49

Quote: (Originally Posted by depth)

Hi RW

If I suddently feel that something is wrong, my thoughts on OC bailout are:

- There is NO WAY I have time to reach down for my OC bailout second stage and switch
- There is little chance I have time to reach up for a BOW and turn a handle

Currently I am diving my Meg standard, but I am considering buying a BOW in the near future.

Safe diving....

Another important reflex (and extremely simple) is to hit your ADV and flush your loop.

I have both my BOV/ADV connected to offboard bailout so I often "waste" dil to check my sensors at depth, or just practise to maintain the skill without affecting bouyancy.

depth · 6th June 2007, 11:36

Ok, I see the points above. But I have never heard of a Rebreather diver actully identifying O2 or CO2 problems and succesfully switching to OC on a normal 2. stage or a BOW and recover! (but maybe i'm just not searching hard enough ;-) I found articles that describes how the RB diver senses that something is wrong, and the next thing he/she wakes up in a hospital thanks to the buddy.

But maybe switching to OC when you feel something is not like it is supposed to be, it is allready to late, and breathing from OC will not suppress the reaction of the buddy (convulsion)?

diverklondike · 6th June 2007, 12:15

Here are a couple things to keep in mind...

1) Good training teaches you how to recognize a potential problem...

2) Practicing the drills you learned during training helps makes these responses closer to a "reflex" action...

3) Diving with a "trained dive buddy" OC or CCR on how to handle an emergency problem helps improve your odds in any situation...

Now given the choice of a 2nd stage hanging around your neck or a BOV, the BOV is a faster/better solution to "clean gas" for all of the above... 1,2 and 3.

I think if you read many of the posts on the list about O2 and CO2 problems you will hear that some people feel the problem coming on and others do not so there is no easy answer other than making sure that you are covered on 1 & 2 as mentioned above and 3 when ever possible....

Dive Safe..

Mark

Ben Field · 6th June 2007, 12:25

Quote: (Originally Posted by depth)

Ok, I see the points above. But I have never heard of a Rebreather diver actully identifying O2 or CO2 problems and succesfully switching to OC on a normal 2. stage or a BOW and recover! (but maybe i'm just not searching hard enough ;-) I found articles that describes how the RB diver senses that something is wrong, and the next thing he/she wakes up in a hospital thanks to the buddy.

I've seen my PPO2 not responding correctly and bailed ot OC to be on the safe side (O2 valve not fully open, opened and returned to CC) I've been breathing hard and thought I might be overbreathing (unable to slow rate after fast descent to 50mtrs) so bailed and caught my breath, eventually!

I also dived with the OPV set open instead of closed and was firing the ADV on every breath, very disconcerting, bailed out and surfaced, thats the only time I've canned a dive on the rebreather but not as potentially dangerous as the first two.

One of my buddies O2 started to overflow, he bailed then isolated the O2 and returned the the loop diving with the O2 valve on/off technique.

Maybe its easy to spot on the KISS as we're glued to our PPO2 displays?

I know those aren't very exciting examples but in each case an O2 or CO2 problem was detected and bailing out either allowed time to fix it or surface.

However you are right in that I too have heard of several instances where divers have gone from seemingly ok to unconsious very rapidly, the only way around that I can see is an Automatic BOV based on CO2 detection... or a full face mask/gag, otherwise your sucking sea, which is abit grim

I guess the rest of us are getting by with good packing, observing the scrubber time limits and avoiding too much work (never a bad thing

)

BEN

Mark Chase · 6th June 2007, 12:38

Quote: (Originally Posted by depth)

Ok, I see the points above. But I have never heard of a Rebreather diver actully identifying O2 or CO2 problems and succesfully switching to OC on a normal 2. stage or a BOW and recover! (but maybe i'm just not searching hard enough ;-) I found articles that describes how the RB diver senses that something is wrong, and the next thing he/she wakes up in a hospital thanks to the buddy.

But maybe switching to OC when you feel something is not like it is supposed to be, it is allready to late, and breathing from OC will not suppress the reaction of the buddy (convulsion)?

Its not hapened to me (YET) but I have buddied two divers who bailed on to OC. Neither wrote up the incident as nothing hapened. They just didnt feel right and bailed out and we ended the dive. Job done.

Only the interesting / exciting ones get writen about I supose.

ATB

Mark Chase

Drmike · 6th June 2007, 13:01

Quote: (Originally Posted by depth)

If I suddently feel that something is wrong, my thoughts on OC bailout are:

- There is NO WAY I have time to reach down for my OC bailout second stage and switch
- There is little chance I have time to reach up for a BOW and turn a handle

Are these assumptions wrong?
..

yes and no

it depends

not all hits/reason to bail, are the same not all come on fast or are undetectable before its too late.

Personally my first reaction/habit to any feeling of weirdness or inappropriate increased breathing rate is to exhale through my nose a few times and fire the adv. Aware now and sensitive of a possible issue I am ready to turn the bov (if im using one) or go to OC if the fresh gas doesnt show signs of illeviating the problem to a manageable level

the main benefit to me in using a bov is the fact that with the increase breathing rate associated with a co2 hit divers are sometimes known (and i have personally experineced this) to be unable to force themselves to remove the dsv their panting from and switch to oc.

As an aside with the Panorma ffm its even easier. I just breath through my nose for instant blast of OC gas without changing anything whenever i feel weird.

Panorma FFM with side OC reg - good combo imho. I dont even use a bov with this mask for this reason as it gives me something to breathe OC whilst fumbling for my OC 2nd stages. The ability to keep breathing (through the nose) is a large stress reducer I find during times of stress/gas switching etc

6th June 2007, 09:24	#1 (permalink)
depth Christian Rasmussen Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Denmark Posts: 195	Is a BOW fast enough to save a life? Hi RW For some time now, I have enjoyed reading the many posts regarding many different subjects on RW. Especially the forum describing accidents and incidents has caught my attention, because i belive that lessons learned from others is priceless information. During my Meg course, my instructor Rasmus Lauritsen from Nordtechdiving.dk (very recomendable instructor), stressed that bailout to OC should be performed very fast if something feels wrong during a dive. When reading the posts from Rebreather divers involved in O2 or CO2 problems, they barely have time to think "bailout" before passing out. If I suddently feel that something is wrong, my thoughts on OC bailout are: - There is NO WAY I have time to reach down for my OC bailout second stage and switch - There is little chance I have time to reach up for a BOW and turn a handle Are these assumptions wrong? Currently I am diving my Meg standard, but I am considering buying a BOW in the near future. Safe diving.... __________________ I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not.............
(Online)

6th June 2007, 10:24	#2 (permalink)
Rebreatherlab RebreatherWorld Sponsor Current Rebreather/s: Pelagian Other Rebreather/s: Not Bought Yet Classic Kiss Pelagian Join Date: Sep 2005 Location: Thailand Posts: 202	Re: Is a BOV fast enough to save a life? As with most things this is also relative to what the problem is and how long it takes you to "feel" something is wrong. If you carry a snd stage on a bungee and dive with the bail valve open it should not take long to get a fresh breath of OC. Still a good quality BOV would cut the time further. Who can say it this is fast enough? Good question, but at the moment there are no faster alternatives. I use my BOV for standard DIL additions during the dive and hope that as the motor skill of operating the BOV gets so hammered in that it will further reduce the respond time in a bail scenario. For 950 USD you can have our high performance BOV that is the most compact out there. It also uses flapper valves made for rebreathers, not standard 2nd stage exhaust valves like you have in your standard Meg DSV. This reduces WOB. This BOV will fit your Meg hoses out of the box and you can swap the mouth piece plate for another to fit a Draeger Panorama fullface mask. This would at least prevent drowning if you dont turn the barrel quick enough. The BOV mechanism comes from a balanced Scubapro S600 regulator and provides easy breathing also at depth. Please PM or email if you are interested. All the best, Andy REBREATHER LAB Quote: (Originally Posted by depth) Hi RW For some time now, I have enjoyed reading the many posts regarding many different subjects on RW. Especially the forum describing accidents and incidents has caught my attention, because i belive that lessons learned from others is priceless information. During my Meg course, my instructor Rasmus Lauritsen from Nordtechdiving.dk (very recomendable instructor), stressed that bailout to OC should be performed very fast if something feels wrong during a dive. When reading the posts from Rebreather divers involved in O2 or CO2 problems, they barely have time to think "bailout" before passing out. If I suddently feel that something is wrong, my thoughts on OC bailout are: - There is NO WAY I have time to reach down for my OC bailout second stage and switch - There is little chance I have time to reach up for a BOW and turn a handle Are these assumptions wrong? Currently I am diving my Meg standard, but I am considering buying a BOW in the near future. Safe diving....
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6th June 2007, 10:30	#3 (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: 2,700	Re: Is a BOW fast enough to save a life? Use a BOV and a gag to keep it in then its your buddies job to turn the knob. Or alternativly use a full face mask. ATB Mark Chase __________________ 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
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6th June 2007, 10:45	#4 (permalink)
nigelh New Member Current Rebreather/s: Inspiration Vision Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Mar 2005 Location: Brighton, Sussex, UK Posts: 839	Re: Is a BOW fast enough to save a life? Quote: (Originally Posted by depth) During my Meg course, my instructor Rasmus Lauritsen from Nordtechdiving.dk (very recomendable instructor), stressed that bailout to OC should be performed very fast if something feels wrong during a dive. When reading the posts from Rebreather divers involved in O2 or CO2 problems, they barely have time to think "bailout" before passing out. Huh? If you're watching the shop oxygen problems shouldn't sneak up on you. CO2 is more of a worry as deep it can apparently start with unconsciousness as the first major sign but the usual complaint shallower is that you can't do anything that stops your hyperventilating breathing. The hope with a BOV is that you can just snap it over and try it on the 'sense of unease' that tends to precede this sort of thing and realise that everything suddenly got better. It isn't a magic cure all but a quicker, easier tool than swapping regs. __________________ nigelh
(Online)

6th June 2007, 10:49	#5 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: Is a BOW fast enough to save a life? Quote: (Originally Posted by depth) Hi RW If I suddently feel that something is wrong, my thoughts on OC bailout are: - There is NO WAY I have time to reach down for my OC bailout second stage and switch - There is little chance I have time to reach up for a BOW and turn a handle Currently I am diving my Meg standard, but I am considering buying a BOW in the near future. Safe diving.... Another important reflex (and extremely simple) is to hit your ADV and flush your loop. I have both my BOV/ADV connected to offboard bailout so I often "waste" dil to check my sensors at depth, or just practise to maintain the skill without affecting bouyancy. __________________ Gilles http://www.dirrebreather.com
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6th June 2007, 11:36	#6 (permalink)
depth Christian Rasmussen Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Denmark Posts: 195	Re: Is a BOW fast enough to save a life? Ok, I see the points above. But I have never heard of a Rebreather diver actully identifying O2 or CO2 problems and succesfully switching to OC on a normal 2. stage or a BOW and recover! (but maybe i'm just not searching hard enough ;-) I found articles that describes how the RB diver senses that something is wrong, and the next thing he/she wakes up in a hospital thanks to the buddy. But maybe switching to OC when you feel something is not like it is supposed to be, it is allready to late, and breathing from OC will not suppress the reaction of the buddy (convulsion)? __________________ I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not qualified to make my own meg batteries!!! I am not.............
(Online)

6th June 2007, 12:15	#7 (permalink)
diverklondike Just one of the Peasants Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Oct 2005 Location: Delaware, USA Posts: 1,613	Re: Is a BOW fast enough to save a life? Here are a couple things to keep in mind... 1) Good training teaches you how to recognize a potential problem... 2) Practicing the drills you learned during training helps makes these responses closer to a "reflex" action... 3) Diving with a "trained dive buddy" OC or CCR on how to handle an emergency problem helps improve your odds in any situation... Now given the choice of a 2nd stage hanging around your neck or a BOV, the BOV is a faster/better solution to "clean gas" for all of the above... 1,2 and 3. I think if you read many of the posts on the list about O2 and CO2 problems you will hear that some people feel the problem coming on and others do not so there is no easy answer other than making sure that you are covered on 1 & 2 as mentioned above and 3 when ever possible.... Dive Safe.. Mark
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6th June 2007, 12:25	#8 (permalink)
Ben Field CK+Shearwater Current Rebreather/s: Classic Kiss Other Rebreather/s: Sport Kiss Join Date: Aug 2005 Location: London, England Posts: 1,622	Re: Is a BOW fast enough to save a life? Quote: (Originally Posted by depth) Ok, I see the points above. But I have never heard of a Rebreather diver actully identifying O2 or CO2 problems and succesfully switching to OC on a normal 2. stage or a BOW and recover! (but maybe i'm just not searching hard enough ;-) I found articles that describes how the RB diver senses that something is wrong, and the next thing he/she wakes up in a hospital thanks to the buddy. I've seen my PPO2 not responding correctly and bailed ot OC to be on the safe side (O2 valve not fully open, opened and returned to CC) I've been breathing hard and thought I might be overbreathing (unable to slow rate after fast descent to 50mtrs) so bailed and caught my breath, eventually! I also dived with the OPV set open instead of closed and was firing the ADV on every breath, very disconcerting, bailed out and surfaced, thats the only time I've canned a dive on the rebreather but not as potentially dangerous as the first two. One of my buddies O2 started to overflow, he bailed then isolated the O2 and returned the the loop diving with the O2 valve on/off technique. Maybe its easy to spot on the KISS as we're glued to our PPO2 displays? I know those aren't very exciting examples but in each case an O2 or CO2 problem was detected and bailing out either allowed time to fix it or surface. However you are right in that I too have heard of several instances where divers have gone from seemingly ok to unconsious very rapidly, the only way around that I can see is an Automatic BOV based on CO2 detection... or a full face mask/gag, otherwise your sucking sea, which is abit grim I guess the rest of us are getting by with good packing, observing the scrubber time limits and avoiding too much work (never a bad thing ) BEN __________________ Know your PPO2, Pre-breath, Use checklists, Validate cells at 6mtrs, Use pure O2 at or near surface, Use a BOV, Don't dive Solo, Change Slime and Cells as recommended by Manufacturer and RTFM! Beware Fridge Suck! www.hugsac.org.uk
(Online)

6th June 2007, 12:38	#9 (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: 2,700	Re: Is a BOW fast enough to save a life? Quote: (Originally Posted by depth) Ok, I see the points above. But I have never heard of a Rebreather diver actully identifying O2 or CO2 problems and succesfully switching to OC on a normal 2. stage or a BOW and recover! (but maybe i'm just not searching hard enough ;-) I found articles that describes how the RB diver senses that something is wrong, and the next thing he/she wakes up in a hospital thanks to the buddy. But maybe switching to OC when you feel something is not like it is supposed to be, it is allready to late, and breathing from OC will not suppress the reaction of the buddy (convulsion)? Its not hapened to me (YET) but I have buddied two divers who bailed on to OC. Neither wrote up the incident as nothing hapened. They just didnt feel right and bailed out and we ended the dive. Job done. Only the interesting / exciting ones get writen about I supose. ATB Mark Chase __________________ 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)

6th June 2007, 13:01	#10 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,325	Re: Is a BOW fast enough to save a life? Quote: (Originally Posted by depth) If I suddently feel that something is wrong, my thoughts on OC bailout are: - There is NO WAY I have time to reach down for my OC bailout second stage and switch - There is little chance I have time to reach up for a BOW and turn a handle Are these assumptions wrong? .. yes and no it depends not all hits/reason to bail, are the same not all come on fast or are undetectable before its too late. Personally my first reaction/habit to any feeling of weirdness or inappropriate increased breathing rate is to exhale through my nose a few times and fire the adv. Aware now and sensitive of a possible issue I am ready to turn the bov (if im using one) or go to OC if the fresh gas doesnt show signs of illeviating the problem to a manageable level the main benefit to me in using a bov is the fact that with the increase breathing rate associated with a co2 hit divers are sometimes known (and i have personally experineced this) to be unable to force themselves to remove the dsv their panting from and switch to oc. As an aside with the Panorma ffm its even easier. I just breath through my nose for instant blast of OC gas without changing anything whenever i feel weird. Panorma FFM with side OC reg - good combo imho. I dont even use a bov with this mask for this reason as it gives me something to breathe OC whilst fumbling for my OC 2nd stages. The ability to keep breathing (through the nose) is a large stress reducer I find during times of stress/gas switching etc __________________ Cave diving is a sport Wreck diving is a sport Diving in general is a sport 'Rebreather diving' is not a sport its the delusional obsession with a highly dangerous and often inappropriate piece of equipment
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