Is Rebreather diving inherently more dangerous than OC?

Mark Chase · 6th January 2007, 12:59

Quote: (Originally Posted by CharlieT)

Janos

I don't disagree that in the few instances you mention, Rebreather diving is generally safer. Of course also for dives like the very deep ones DrMike does.

Charlie

I don't disagree that CCR is more challenging to dive than OC but I disagree with your depth range.

I have already been in situations where problems have occurred and yet you can stay perfectly relaxed because your not time limited. Its a nice feeling.

I suggest that deep OC diving takes a lot of discipline and equipment monitoring / preparation. As such it compares with CCR in terms of complexity. Divers die OC because they run out of gas or switch to the wrong mix, don't analise their gas and dive the wrong mix. Divers die on CCR because they don't switch their 02 on or they ignore warnings on the hand sets.

Simple stuff. KISS type divers have decided to purchase a unit which demands constant observation. Eccr divers chose a unit that doesn't. This may reflect something about the nature of the divers them selves. I personally believe that a properly monitored ECCR is safer then a MCCR. In time of distraction and chaos the unit can take over and keep you alive.

However i don't believe that for general diving the ECCR diver can afford to be any less vigilant than the MCCR diver.

ATB

Mark Chase

CharlieT · 6th January 2007, 13:26

Quote: (Originally Posted by Mark Chase)

I don't disagree that CCR is more challenging to dive than OC but I disagree with your depth range.

I have already been in situations where problems have occurred and yet you can stay perfectly relaxed because your not time limited. Its a nice feeling.

I suggest that deep OC diving takes a lot of discipline and equipment monitoring / preparation. As such it compares with CCR in terms of complexity. Divers die OC because they run out of gas or switch to the wrong mix, don't analise their gas and dive the wrong mix. Divers die on CCR because they don't switch their 02 on or they ignore warnings on the hand sets.

Simple stuff. KISS type divers have decided to purchase a unit which demands constant observation. Eccr divers chose a unit that doesn't. This may reflect something about the nature of the divers them selves. I personally believe that a properly monitored ECCR is safer then a MCCR. In time of distraction and chaos the unit can take over and keep you alive.

However i don't believe that for general diving the ECCR diver can afford to be any less vigilant than the MCCR diver.

ATB

Mark Chase

It takes no skill to not run out of gas but if you are a "run out of petrol in a car" type, perhaps you shouldn't be diving at all?

Again, I know of a OC diver who put his 100% reg instead of his 50% reg in his mouth at 20m. The obvious happened. He was diving DIR style with both cylinders on his left. For a simpleton like me, when I was on OC, I used to cope very nicely with lean on left, rich on right!

If an OC diver can't dive on the right bottom mix, I don't know what to say?
It's a very simple calculation.

When I dived the FE on 30 October there were two guys on board with 12L twinsets and a couple of 7's each. It's true they only had a 15 min BT whereas the Rebreather divers were doing between 30 & 40 mins but there was nothing complex about their OC dive.

Want to do longer BT on OC, buy 15's or 18's and bigger sides, 10L steels or ali 80's.

Beyond 85m, I agree with you Mark, I am sure OC diving is as complex as CCR.

I have generously assumed that our OC and CCR divers have all been able to turn on their cylinders. Perhaps I'm being a little too generous

If a Rebreather isn't a complex and unreliable bit of kit compared to OC, why am I thinking of buying a BOV (another £600 or so) and possibly an additional O2 monitor at £x extra?

Why are so many Rebreather members saying that we can all expect our units to go wrong underwater, it's just a question of when not if?

No one said this to me when I was a noisemaker

Charlie

Janos · 6th January 2007, 13:33

Quote: (Originally Posted by CharlieT)

It takes no skill to not run out of gas but if you are a "run out of petrol in a car" type, perhaps you shouldn't be diving at all?

It depends if you run out of petrol through your own neligence, or for circumstances beyond your control.

Rebreathers give you time. As you say, the OC FE divers have a 15 min bottom time. What happens if after 15 minutes the line breaks; they get trapped in monofilament; etc etc?

Equipment failure is not the only thing that can go wrong.

Janos

CharlieT · 6th January 2007, 13:37

Quote: (Originally Posted by Janos)

It depends if you run out of petrol through your own neligence, or for circumstances beyond your control.

Rebreathers give you time. As you say, the OC FE divers have a 15 min bottom time. What happens if after 15 minutes the line breaks; they get trapped in monofilament; etc etc?

Equipment failure is not the only thing that can go wrong.

Janos

Rule of thirds?

Charlie

paulraymaekers · 6th January 2007, 13:55

I don't think there is a simple yes or no..

shallow diving, no overhead, good viz, no current... OC is less dangerous (less things that can go wrong)

worse conditions, Rebreather gives you the advantage of time in case of a problem

regards
paul

Mark Chase · 6th January 2007, 14:25

Quote: (Originally Posted by CharlieT)

Rule of thirds?

Charlie

Nice idea but not many follow this cave diving / penitration concept when diving OW. Being tight on back gas was very common when we were all on OC. Twin 12s were regularly used for 30min + run times at 70m. Twin 15s for 40min+ bottom times.

I only knew one diver who used 18s and he dived air and decoed out on back gas.

Trimix analisors were not common unitll recently As a result stories of dodgy bottom mixes were common. We did a dive out of Weymouth and after picking up the gas from the shop we analised it with our own Trimix analisor and foungd the 21/35 back gas requested had errrrr no Helium in at all

. The planned 55m dive would have had Dave narked out of his head as he suffered quite badly below 40m.

I have had 15/55 shop fills that i took arround to Pete and found once analised were 15/30 so i know for a fact that divers have ignorantly been narked stupid at depth but that they beleived thay had adiquate helium for the dive.

After the above incident I refused to get mix fill anywhere where I couldent analise them. Last year I baught my own Trimix analisor. The shop in question STIL dosent have one.

Errors on deco mixes are a common cause of death or near death on OC deep dives. I had a cloase call once when i switched from back gas to a deco mix that was presurised but switched off. Spit purge the reg breath in no gas at 40m. Bugger. Turn on gas swallow loads of water cough a lot then continue deco. Sounds simple enough but i recall it being a touch and go situation.

On CCR were not exposed to the risks of gas switching we stay on loop for the whole dive and this makes deco safer IMHO. asuming the unit is functioning corectly.

Lets face it If someone OW qualified wanted to go to 100m if they used a CCR all they had to do is breath and folow the instructions on the wrist unit. What could be safer than that.

atb

Mark Chase

CharlieT · 6th January 2007, 15:19

Quote: (Originally Posted by Mark Chase)

Nice idea but not many follow this cave diving / penitration concept when diving OW. Being tight on back gas was very common when we were all on OC. Twin 12s were regularly used for 30min + run times at 70m. Twin 15s for 40min+ bottom times.

I only knew one diver who used 18s and he dived air and decoed out on back gas.

Trimix analisors were not common unitll recently As a result stories of dodgy bottom mixes were common. We did a dive out of Weymouth and after picking up the gas from the shop we analised it with our own Trimix analisor and foungd the 21/35 back gas requested had errrrr no Helium in at all

. The planned 55m dive would have had Dave narked out of his head as he suffered quite badly below 40m.

I have had 15/55 shop fills that i took arround to Pete and found once analised were 15/30 so i know for a fact that divers have ignorantly been narked stupid at depth but that they beleived thay had adiquate helium for the dive.

After the above incident I refused to get mix fill anywhere where I couldent analise them. Last year I baught my own Trimix analisor. The shop in question STIL dosent have one.

Errors on deco mixes are a common cause of death or near death on OC deep dives. I had a cloase call once when i switched from back gas to a deco mix that was presurised but switched off. Spit purge the reg breath in no gas at 40m. Bugger. Turn on gas swallow loads of water cough a lot then continue deco. Sounds simple enough but i recall it being a touch and go situation.

On CCR were not exposed to the risks of gas switching we stay on loop for the whole dive and this makes deco safer IMHO. asuming the unit is functioning corectly.

Lets face it If someone OW qualified wanted to go to 100m if they used a CCR all they had to do is breath and folow the instructions on the wrist unit. What could be safer than that.

atb

Mark Chase

I do so love reading your posts

There's always an adventure, I feel a very dull person

My LDS is about to start using a trimix analyser so, like you, I bought one last year at LIDS.

If we dive together sometime this year, will my kit start behaving like your's

Charlie

Janos · 6th January 2007, 19:23

Quote: (Originally Posted by CharlieT)

Rule of thirds?

It depends how severe the problem is. For a 15 minute bottom time, then you've got an extra 7.5 minutes to sort it out. If you can keep your breathing under control.

Good conditions I'm not so worried about, but it's the 2-3m of viz and pitch black dives that concern me. There's something reassuring about having several hours to sort something out.

Janos

**jmurba** · 6th January 2007, 20:56

Quote: (Originally Posted by sabgia)

A properly managed eCCCR is safer than a properly managed mCCR.

to be perfectly honest
I find you really presumptuous to do such a statement, rebreatherworld is not a boxing ring with passive scr divers, constant mass flow scr divers, eccr divers , and mccr divers on it .

regards

jean mi

Gilles · 6th January 2007, 23:20

Quote: (Originally Posted by Mark Chase)

Divers die OC because they run out of gas or switch to the wrong mix, don't analise their gas and dive the wrong mix. Divers die on CCR because they don't switch their 02 on or they ignore warnings on the hand sets.

Simple stuff. KISS type divers have decided to purchase a unit which demands constant observation. Eccr divers chose a unit that doesn't. This may reflect something about the nature of the divers them selves. I personally believe that a properly monitored ECCR is safer then a MCCR. In time of distraction and chaos the unit can take over and keep you alive.

However i don't believe that for general diving the ECCR diver can afford to be any less vigilant than the MCCR diver.

ATB

Mark Chase

I almost share your view.

I think all electro-chemical cell controlled systems are susceptible to current limitation, thus giving you all the right readings while toxing you out. Thus treachery even with adequate monitoring, e- or m- CCR.

Quote: (Originally Posted by jmurba)

to be perfectly honest
I find you really presumptuous to do such a statement, rebreatherworld is not a boxing ring with passive scr divers, constant mass flow scr divers, eccr divers , and mccr divers on it .

regards

jean mi

In quoting me, I request you include the reason why I think this is so.

That way I won't seem so presumptuous

.

Selective quotations can be dangerous. Please handle with care.

View Poll Results: Is Rebreather diving more dangerous than OC?
Yes, of course!	81	50.63%
No.	61	38.13%
Don't really know ...	17	10.63%
I don't have an opinion ...	1	0.63%
Voters: 160. You may not vote on this poll

6th January 2007, 12:59	#41 (permalink)
Mark Chase RBW Member Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,858	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by CharlieT) Janos I don't disagree that in the few instances you mention, Rebreather diving is generally safer. Of course also for dives like the very deep ones DrMike does. Charlie I don't disagree that CCR is more challenging to dive than OC but I disagree with your depth range. I have already been in situations where problems have occurred and yet you can stay perfectly relaxed because your not time limited. Its a nice feeling. I suggest that deep OC diving takes a lot of discipline and equipment monitoring / preparation. As such it compares with CCR in terms of complexity. Divers die OC because they run out of gas or switch to the wrong mix, don't analise their gas and dive the wrong mix. Divers die on CCR because they don't switch their 02 on or they ignore warnings on the hand sets. Simple stuff. KISS type divers have decided to purchase a unit which demands constant observation. Eccr divers chose a unit that doesn't. This may reflect something about the nature of the divers them selves. I personally believe that a properly monitored ECCR is safer then a MCCR. In time of distraction and chaos the unit can take over and keep you alive. However i don't believe that for general diving the ECCR diver can afford to be any less vigilant than the MCCR diver. ATB Mark Chase __________________ See my "Doing It Chasey" video where I'm locked into a padded room, naked, with two ball bearings and within an Hour, I manage to lose one and break the other!!! Kevin Juergensen 16/11/08 [/quote]
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6th January 2007, 13:26	#42 (permalink)
CharlieT Custom Title Allowed! Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Nov 2005 Location: London Posts: 449	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by Mark Chase) I don't disagree that CCR is more challenging to dive than OC but I disagree with your depth range. I have already been in situations where problems have occurred and yet you can stay perfectly relaxed because your not time limited. Its a nice feeling. I suggest that deep OC diving takes a lot of discipline and equipment monitoring / preparation. As such it compares with CCR in terms of complexity. Divers die OC because they run out of gas or switch to the wrong mix, don't analise their gas and dive the wrong mix. Divers die on CCR because they don't switch their 02 on or they ignore warnings on the hand sets. Simple stuff. KISS type divers have decided to purchase a unit which demands constant observation. Eccr divers chose a unit that doesn't. This may reflect something about the nature of the divers them selves. I personally believe that a properly monitored ECCR is safer then a MCCR. In time of distraction and chaos the unit can take over and keep you alive. However i don't believe that for general diving the ECCR diver can afford to be any less vigilant than the MCCR diver. ATB Mark Chase It takes no skill to not run out of gas but if you are a "run out of petrol in a car" type, perhaps you shouldn't be diving at all? Again, I know of a OC diver who put his 100% reg instead of his 50% reg in his mouth at 20m. The obvious happened. He was diving DIR style with both cylinders on his left. For a simpleton like me, when I was on OC, I used to cope very nicely with lean on left, rich on right! If an OC diver can't dive on the right bottom mix, I don't know what to say? It's a very simple calculation. When I dived the FE on 30 October there were two guys on board with 12L twinsets and a couple of 7's each. It's true they only had a 15 min BT whereas the Rebreather divers were doing between 30 & 40 mins but there was nothing complex about their OC dive. Want to do longer BT on OC, buy 15's or 18's and bigger sides, 10L steels or ali 80's. Beyond 85m, I agree with you Mark, I am sure OC diving is as complex as CCR. I have generously assumed that our OC and CCR divers have all been able to turn on their cylinders. Perhaps I'm being a little too generous If a Rebreather isn't a complex and unreliable bit of kit compared to OC, why am I thinking of buying a BOV (another £600 or so) and possibly an additional O2 monitor at £x extra? Why are so many Rebreather members saying that we can all expect our units to go wrong underwater, it's just a question of when not if? No one said this to me when I was a noisemaker Charlie
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6th January 2007, 13:33	#43 (permalink)
Janos "Two Sheds" Current Rebreather/s: Classic Kiss Other Rebreather/s: Classic Kiss Join Date: Feb 2005 Location: East Surrey Posts: 632	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by CharlieT) It takes no skill to not run out of gas but if you are a "run out of petrol in a car" type, perhaps you shouldn't be diving at all? It depends if you run out of petrol through your own neligence, or for circumstances beyond your control. Rebreathers give you time. As you say, the OC FE divers have a 15 min bottom time. What happens if after 15 minutes the line breaks; they get trapped in monofilament; etc etc? Equipment failure is not the only thing that can go wrong. Janos __________________ You can lead a horse to water but you can't climb a ladder with a large bell in both hands - Vic Reeves www.hellfins.com/shed
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6th January 2007, 13:37	#44 (permalink)
CharlieT Custom Title Allowed! Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Nov 2005 Location: London Posts: 449	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by Janos) It depends if you run out of petrol through your own neligence, or for circumstances beyond your control. Rebreathers give you time. As you say, the OC FE divers have a 15 min bottom time. What happens if after 15 minutes the line breaks; they get trapped in monofilament; etc etc? Equipment failure is not the only thing that can go wrong. Janos Rule of thirds? Charlie
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6th January 2007, 13:55	#45 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,638	Re: Is Rebreather diving inherently more dangerous than OC? I don't think there is a simple yes or no.. shallow diving, no overhead, good viz, no current... OC is less dangerous (less things that can go wrong) worse conditions, Rebreather gives you the advantage of time in case of a problem regards paul __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...
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6th January 2007, 14:25	#46 (permalink)
Mark Chase RBW Member Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,858	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by CharlieT) Rule of thirds? Charlie Nice idea but not many follow this cave diving / penitration concept when diving OW. Being tight on back gas was very common when we were all on OC. Twin 12s were regularly used for 30min + run times at 70m. Twin 15s for 40min+ bottom times. I only knew one diver who used 18s and he dived air and decoed out on back gas. Trimix analisors were not common unitll recently As a result stories of dodgy bottom mixes were common. We did a dive out of Weymouth and after picking up the gas from the shop we analised it with our own Trimix analisor and foungd the 21/35 back gas requested had errrrr no Helium in at all . The planned 55m dive would have had Dave narked out of his head as he suffered quite badly below 40m. I have had 15/55 shop fills that i took arround to Pete and found once analised were 15/30 so i know for a fact that divers have ignorantly been narked stupid at depth but that they beleived thay had adiquate helium for the dive. After the above incident I refused to get mix fill anywhere where I couldent analise them. Last year I baught my own Trimix analisor. The shop in question STIL dosent have one. Errors on deco mixes are a common cause of death or near death on OC deep dives. I had a cloase call once when i switched from back gas to a deco mix that was presurised but switched off. Spit purge the reg breath in no gas at 40m. Bugger. Turn on gas swallow loads of water cough a lot then continue deco. Sounds simple enough but i recall it being a touch and go situation. On CCR were not exposed to the risks of gas switching we stay on loop for the whole dive and this makes deco safer IMHO. asuming the unit is functioning corectly. Lets face it If someone OW qualified wanted to go to 100m if they used a CCR all they had to do is breath and folow the instructions on the wrist unit. What could be safer than that. atb Mark Chase __________________ See my "Doing It Chasey" video where I'm locked into a padded room, naked, with two ball bearings and within an Hour, I manage to lose one and break the other!!! Kevin Juergensen 16/11/08 [/quote]
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6th January 2007, 15:19	#47 (permalink)
CharlieT Custom Title Allowed! Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Nov 2005 Location: London Posts: 449	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by Mark Chase) Nice idea but not many follow this cave diving / penitration concept when diving OW. Being tight on back gas was very common when we were all on OC. Twin 12s were regularly used for 30min + run times at 70m. Twin 15s for 40min+ bottom times. I only knew one diver who used 18s and he dived air and decoed out on back gas. Trimix analisors were not common unitll recently As a result stories of dodgy bottom mixes were common. We did a dive out of Weymouth and after picking up the gas from the shop we analised it with our own Trimix analisor and foungd the 21/35 back gas requested had errrrr no Helium in at all . The planned 55m dive would have had Dave narked out of his head as he suffered quite badly below 40m. I have had 15/55 shop fills that i took arround to Pete and found once analised were 15/30 so i know for a fact that divers have ignorantly been narked stupid at depth but that they beleived thay had adiquate helium for the dive. After the above incident I refused to get mix fill anywhere where I couldent analise them. Last year I baught my own Trimix analisor. The shop in question STIL dosent have one. Errors on deco mixes are a common cause of death or near death on OC deep dives. I had a cloase call once when i switched from back gas to a deco mix that was presurised but switched off. Spit purge the reg breath in no gas at 40m. Bugger. Turn on gas swallow loads of water cough a lot then continue deco. Sounds simple enough but i recall it being a touch and go situation. On CCR were not exposed to the risks of gas switching we stay on loop for the whole dive and this makes deco safer IMHO. asuming the unit is functioning corectly. Lets face it If someone OW qualified wanted to go to 100m if they used a CCR all they had to do is breath and folow the instructions on the wrist unit. What could be safer than that. atb Mark Chase I do so love reading your posts There's always an adventure, I feel a very dull person My LDS is about to start using a trimix analyser so, like you, I bought one last year at LIDS. If we dive together sometime this year, will my kit start behaving like your's Charlie
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6th January 2007, 19:23	#48 (permalink)
Janos "Two Sheds" Current Rebreather/s: Classic Kiss Other Rebreather/s: Classic Kiss Join Date: Feb 2005 Location: East Surrey Posts: 632	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by CharlieT) Rule of thirds? It depends how severe the problem is. For a 15 minute bottom time, then you've got an extra 7.5 minutes to sort it out. If you can keep your breathing under control. Good conditions I'm not so worried about, but it's the 2-3m of viz and pitch black dives that concern me. There's something reassuring about having several hours to sort something out. Janos __________________ You can lead a horse to water but you can't climb a ladder with a large bell in both hands - Vic Reeves www.hellfins.com/shed
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6th January 2007, 20:56	#49 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by sabgia) A properly managed eCCCR is safer than a properly managed mCCR. to be perfectly honest I find you really presumptuous to do such a statement, rebreatherworld is not a boxing ring with passive scr divers, constant mass flow scr divers, eccr divers , and mccr divers on it . regards jean mi
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6th January 2007, 23:20	#50 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: Is Rebreather diving inherently more dangerous than OC? Quote: (Originally Posted by Mark Chase) Divers die OC because they run out of gas or switch to the wrong mix, don't analise their gas and dive the wrong mix. Divers die on CCR because they don't switch their 02 on or they ignore warnings on the hand sets. Simple stuff. KISS type divers have decided to purchase a unit which demands constant observation. Eccr divers chose a unit that doesn't. This may reflect something about the nature of the divers them selves. I personally believe that a properly monitored ECCR is safer then a MCCR. In time of distraction and chaos the unit can take over and keep you alive. However i don't believe that for general diving the ECCR diver can afford to be any less vigilant than the MCCR diver. ATB Mark Chase I almost share your view. I think all electro-chemical cell controlled systems are susceptible to current limitation, thus giving you all the right readings while toxing you out. Thus treachery even with adequate monitoring, e- or m- CCR. Quote: (Originally Posted by jmurba) to be perfectly honest I find you really presumptuous to do such a statement, rebreatherworld is not a boxing ring with passive scr divers, constant mass flow scr divers, eccr divers , and mccr divers on it . regards jean mi In quoting me, I request you include the reason why I think this is so. That way I won't seem so presumptuous . Selective quotations can be dangerous. Please handle with care. __________________ Gilles http://www.dirrebreather.com Last edited by Gilles : 6th January 2007 at 23:27.
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