Ascent rate on O2 unit

Digger · 22nd February 2005, 21:23

OK guys, here's one to get a bit of debate going, as I've been thinking again. I know, bad idea.

Anyway, I was reading in Bozenich's book (very goo read by the way for early on Rebreather diving) that you can dive an O2 RB any time right up to flying, as obviously there's no N2 to cause a bend in the aircraft, so all the better.

So I got me to thinking about things. If you're diving an O2 unit, does this mean (lung injuries aside, assuming you are breathing out on the way up and all that PADI guff) that you can yoyo like a madman on an O2 unit in the shallows, provided you've not been off diving beforehand, that is.

Could I do the polaris ascent I've been planning as part of a rescue scenario and actually get myself well clear of the water doing this, only to then sink gently back into the deep? I just like making things nice and realistic for drills! I mean coming up at 100m/min, reckon it's possible if I was to attatch myself to something big and inflate everything? Was thinking about the cockpit in Stoney.

So, let opinions roll in, I want to know whether this is bad. Can't be possible to get an O2 bend, so what would I get? Other than burst lungs, that is. We left that out further up the page.

Digs.

***EBT*** · 22nd February 2005, 21:27

You can get an O2 bend, although obviously by their very nature they're transient. I'll have a dig around and see if I can find you a reference......

/Z

Diving Dude · 22nd February 2005, 23:29

l'm sorry Digger mate l can't help with your question, but can l please be your buddy when you try this out, l'll just sit by the cockpit and watch.

Duncan Price · 23rd February 2005, 08:07

Quote: (Originally Posted by wreckweasel)

You can get an O2 bend, although obviously by their very nature they're transient. I'll have a dig around and see if I can find you a reference......

I've seen film footage of an O2 bend duirng the Wakulla 2 project. Not nice. Happened to Jason Richards (rchrds - on this forum) though maybe he won't remember it as he was too busy convulsing at the time. He did go awfully deep (the bottom of the spring) on pure O2 by accident.

aquaholic · 25th February 2005, 14:27

Quote: (Originally Posted by Digger)

Can't be possible to get an O2 bend, so what would I get? Other than burst lungs, that is. We left that out further up the page.Digs.

Hi Digger,

Here is my take, I'm sure somebody will tell me if I'm talking rubbish..

Bends are about bubble formation. _ANY_ gas can bubble if you ascend too fast. So yes, you can get an O2 bend. Your venous blood will always have less O2 than your tissues even if you breathe 100% O2, so you still have a gradient, even if small - hence you can get O2 bubbles forming... I would say - fast ascent is a no-no on any gas.

Take care

A

***Decodiver*** · 26th February 2005, 15:53

Quote: (Originally Posted by Digger)

OK guys, here's one to get a bit of debate going, as I've been thinking again. I know, bad idea.

Anyway, I was reading in Bozenich's book (very goo read by the way for early on Rebreather diving) that you can dive an O2 RB any time right up to flying, as obviously there's no N2 to cause a bend in the aircraft, so all the better.

So I got me to thinking about things. If you're diving an O2 unit, does this mean (lung injuries aside, assuming you are breathing out on the way up and all that PADI guff) that you can yoyo like a madman on an O2 unit in the shallows, provided you've not been off diving beforehand, that is.

Could I do the polaris ascent I've been planning as part of a rescue scenario and actually get myself well clear of the water doing this, only to then sink gently back into the deep? I just like making things nice and realistic for drills! I mean coming up at 100m/min, reckon it's possible if I was to attatch myself to something big and inflate everything? Was thinking about the cockpit in Stoney.

So, let opinions roll in, I want to know whether this is bad. Can't be possible to get an O2 bend, so what would I get? Other than burst lungs, that is. We left that out further up the page.

Digs.

Digs you Lunatic!

You better have a good flush technique going to be on pure O2, including your prebreathe protocols......

As someone with many hundreds of hours on O2 RBs, I was always taught to reduce my ascent rates accordingly, having said that we were allowed to go to a PPO2 of 5 bar for 45 seconds if necessary! Gas physics, physiology aside, mean that we should always minimise our ascent rates regardless of breathing mix.

Cheers

Dave Cooper

Digger · 1st March 2005, 17:10

Aaah, I reckon you're all being big jessies about it.

I don't much like the sound of an O2 bend though.

I must be able to find a way. If we got a FFM I could try it a bit deeper too. Anyone for the SETT tank? 30m on O2 must be possible, if a little ill-advised...

22nd February 2005, 21:23	#1 (permalink)
Digger Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Not Bought Yet Inspiration Classic Classic Kiss Join Date: Feb 2005 Location: Midlands UK Posts: 206	Ascent rate on O2 unit OK guys, here's one to get a bit of debate going, as I've been thinking again. I know, bad idea. Anyway, I was reading in Bozenich's book (very goo read by the way for early on Rebreather diving) that you can dive an O2 RB any time right up to flying, as obviously there's no N2 to cause a bend in the aircraft, so all the better. So I got me to thinking about things. If you're diving an O2 unit, does this mean (lung injuries aside, assuming you are breathing out on the way up and all that PADI guff) that you can yoyo like a madman on an O2 unit in the shallows, provided you've not been off diving beforehand, that is. Could I do the polaris ascent I've been planning as part of a rescue scenario and actually get myself well clear of the water doing this, only to then sink gently back into the deep? I just like making things nice and realistic for drills! I mean coming up at 100m/min, reckon it's possible if I was to attatch myself to something big and inflate everything? Was thinking about the cockpit in Stoney. So, let opinions roll in, I want to know whether this is bad. Can't be possible to get an O2 bend, so what would I get? Other than burst lungs, that is. We left that out further up the page. Digs.
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22nd February 2005, 21:27	#2 (permalink)
*EBT* Apprentice Luddite Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: UK, Brighton Posts: 1,903	You can get an O2 bend, although obviously by their very nature they're transient. I'll have a dig around and see if I can find you a reference...... /Z __________________ Eagles May Soar, but weasels don't get sucked into jet engines! Rebreather World Terms of service Real diving t-shirts for real divers
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22nd February 2005, 23:29	#3 (permalink)
Diving Dude New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Stanmore, SE England Posts: 23	l'm sorry Digger mate l can't help with your question, but can l please be your buddy when you try this out, l'll just sit by the cockpit and watch. __________________ Howard
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23rd February 2005, 08:07	#4 (permalink)
Duncan Price Sump Monster Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Feb 2005 Location: Wells, Somerset, UK Posts: 336	Quote: (Originally Posted by wreckweasel) You can get an O2 bend, although obviously by their very nature they're transient. I'll have a dig around and see if I can find you a reference...... I've seen film footage of an O2 bend duirng the Wakulla 2 project. Not nice. Happened to Jason Richards (rchrds - on this forum) though maybe he won't remember it as he was too busy convulsing at the time. He did go awfully deep (the bottom of the spring) on pure O2 by accident.
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25th February 2005, 14:27	#5 (permalink)
aquaholic hohum Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: UK Posts: 100	Quote: (Originally Posted by Digger) Can't be possible to get an O2 bend, so what would I get? Other than burst lungs, that is. We left that out further up the page.Digs. Hi Digger, Here is my take, I'm sure somebody will tell me if I'm talking rubbish.. Bends are about bubble formation. _ANY_ gas can bubble if you ascend too fast. So yes, you can get an O2 bend. Your venous blood will always have less O2 than your tissues even if you breathe 100% O2, so you still have a gradient, even if small - hence you can get O2 bubbles forming... I would say - fast ascent is a no-no on any gas. Take care A
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26th February 2005, 15:53	#6 (permalink)
*Decodiver* Administrator Current Rebreather/s: Megalodon Ouroboros rEvo Other CCR Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Classic Kiss rEvo Other CCR Join Date: Jan 2005 Location: Geneva Posts: 2,178	Quote: (Originally Posted by Digger) OK guys, here's one to get a bit of debate going, as I've been thinking again. I know, bad idea. Anyway, I was reading in Bozenich's book (very goo read by the way for early on Rebreather diving) that you can dive an O2 RB any time right up to flying, as obviously there's no N2 to cause a bend in the aircraft, so all the better. So I got me to thinking about things. If you're diving an O2 unit, does this mean (lung injuries aside, assuming you are breathing out on the way up and all that PADI guff) that you can yoyo like a madman on an O2 unit in the shallows, provided you've not been off diving beforehand, that is. Could I do the polaris ascent I've been planning as part of a rescue scenario and actually get myself well clear of the water doing this, only to then sink gently back into the deep? I just like making things nice and realistic for drills! I mean coming up at 100m/min, reckon it's possible if I was to attatch myself to something big and inflate everything? Was thinking about the cockpit in Stoney. So, let opinions roll in, I want to know whether this is bad. Can't be possible to get an O2 bend, so what would I get? Other than burst lungs, that is. We left that out further up the page. Digs. Digs you Lunatic! You better have a good flush technique going to be on pure O2, including your prebreathe protocols...... As someone with many hundreds of hours on O2 RBs, I was always taught to reduce my ascent rates accordingly, having said that we were allowed to go to a PPO2 of 5 bar for 45 seconds if necessary! Gas physics, physiology aside, mean that we should always minimise our ascent rates regardless of breathing mix. Cheers Dave Cooper __________________ CCR/OC Trimix Instructor Trainer CCR Training to Mixed Gas in Switzerland, France, UK & Germany on Megalodon/COPIS-Megalodon/KISS/Sport KISS/Ouroboros/rEvo/Inspiration/Evolution/Sentinel www.zerogravitydiving.com Rebreather World Terms & Conditions
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1st March 2005, 17:10	#7 (permalink)
Digger Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Not Bought Yet Inspiration Classic Classic Kiss Join Date: Feb 2005 Location: Midlands UK Posts: 206	Aaah, I reckon you're all being big jessies about it. I don't much like the sound of an O2 bend though. I must be able to find a way. If we got a FFM I could try it a bit deeper too. Anyone for the SETT tank? 30m on O2 must be possible, if a little ill-advised...
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