Bailout Gases for long 60 metre dives

divetheworld · 30th September 2006, 08:53

Quote: (Originally Posted by decoweenie)

I have a hypothetical question...

If only 1% of the CCR dives resulted in requiring OC-bail-out from the bottom to surface, how many people would be willing to accept this risk for the sake of diving uncumbered without stages knowing that if they have a loop flood, they will die ?

That means 1 in 100 dives, so could be a high percentage. So let's reduce to 0.5%, that means 1 complete loop flood in 200 dives.

Or let's say 1 in 500 dives ? Remember it could happen anytime between dive 1 and 500..

Who would take this risk ?

I know a few alpinist divers. Some are just lazy and complacent, but some are fully aware of the risk but willing to accept the percentage.

I know you didn't ask about alpinist, but IMHO, there is no such thing as semi-alpinist (i.e. like semi pregnant) so either you have adequate OC bail-out or you don't. So having a small amount of off-board gas just to take "sanity breaths" is alpinist in my book.

What would someone do when after taking a few sanity breaths, they realize that they can't get back on the loop and not having adequate OC-bail-out ?

Back to the old chestnut of 'do you include inboard' in your bail plans or not?
Personally, I conside OC bail to be 'last line of defence' so assume complete and catastrophic failure. If the inboard is in tact then its a bonus in the fact that I have some 100% for the 6m stop. The rest of the inboard is just sanity breath to the BOV.
I tend to keep the He content of the primary bail the same as the Dil. How much bail is a matter of new debate for me. When my mate John had a Co2 hit, his RMV hit 90. I have to conclude that planning bail on normal to slightly elevated RMV is not the best idea.

Brent.

decoweenie · 30th September 2006, 09:00

Quote: (Originally Posted by divetheworld)

Back to the old chestnut...

If the inboard is in tact then its a bonus in the fact that I have some 100% for the 6m stop.

Speaking of old chestnut...

Some people are concerned about the additional connection (to breath on-board O2 as OC) to be a potential failure source. If the loop is intact but all O2 is lost, then the unit is potentially useless (unless you could plumb in off-board deco gas = another connector failure source)...

And so on, and so on...

divetheworld · 30th September 2006, 09:06

Quote: (Originally Posted by decoweenie)

Speaking of old chestnut...

Some people are concerned about the additional connection (to breath on-board O2 as OC) to be a potential failure source. If the loop is intact but all O2 is lost, then the unit is potentially useless (unless you could plumb in off-board deco gas = another connector failure source)...

And so on, and so on...

And they are right to give it consideration. I did.
The Dil and O2 go to a gas switching block which feeds my BOV. It is default switched to the dil for sanity breaths. If I need it at 6m then a quick switch. If the BOV or GCS to the BOV fails then I only loose the dil. Ho hum.
Failure of the pipework to the switch block or the switch block itself is an acceptable one to me. Then its off to the stages and out of the water sharpish.
I dont think hanging a reg off the inboard o2 is a good idea without a flow stop. Even then, I prefer my way because the pipes are short and well protected in this little frame thing I have.

Brent.

your frame - GRP Services
gas switching - GRP Services

pchanning · 30th September 2006, 12:22

Quote: (Originally Posted by decoweenie)

Speaking of old chestnut...

Some people are concerned about the additional connection (to breath on-board O2 as OC) to be a potential failure source. If the loop is intact but all O2 is lost, then the unit is potentially useless (unless you could plumb in off-board deco gas = another connector failure source)...

And so on, and so on...

Exactly. I lost my o2 from the 1st stage (right at the end of the dive). So I carried redundant o2 from that point. I later had BOTH handsets go down (Inspo) on the bottom (however, I never bothered with a 4th cells as they were rubbish) and so on, and so on. But, it has to end somewhere...

I have found that this 'counter culture', can be counter productive. I have seen a diver come unstuck (very deep) because of too many ideas and 'things' either getting in the way / badly configured. When it mattered, all the 'gear' was a real hindrance, not a help. That was where it ended for me (and him - nearly). I just carry OC and dive a clean unit. Life is simple and the diving all the more enjoyable for it.

Maybe I am like the perverbeal (sp?) donkey that when faced with two bails of hay, ends up starving.

Anyway, getting back to the thread title, the good thing about 3 optimised tins (which I have never tried) is that if one reg went wrong then it could be swopped out whilst staying OC. Which sounds quite sensible to me.

Cheers
Paul

Drmike · 30th September 2006, 18:54

Quote: (Originally Posted by lbihler)

Hi all,

I m going on a Deep Virgin Wreck diving livaboard south thailand next week. I just can t figure out which gases I would take for bailout. I m quite a beginner on deep wreck dives and wanted your opinion before doing a fatal mistake.
Profile is usually 60 metres for 40 minutes, 2 dives a day. Onboard I use 100% (98) and 14/44 trimix, 1.0 ppO2 bottom 1.4 ppO2 ascent for that mix.

Knowing that they have O2 at will at 6 metres under the boat and that I can not really count on other divers as I will probably be the only CCR diver and as everybody tends to go solo.
Last time I took 12litres Air and 12 litres 36% as bailout, which is enough for me to complete all my deco on OC. Thing is I ran out of O2 during the dive (stupid me, don t ask) with a fully functionning unit and had to ascent in semi closed, which took me ages to deco.

Question is, what would you guys use, knowing that available gases are any mix below 40% O2 including air and trimix, and 100% O2 ?

I was thinking about taking a 12litres Air at 200 bars
and a 12litres 02 at about 100 bars (no booster on the boat) so that even if I work a bit at the bottom I have enough O2 to finish in fully closed and I can
fly the unit manually and spare my back gas for emergencies.
I ll be a bit short on OC ascent if the problem occurs at the end of the dive and I do not find the deco bars (not a probable case, brilliant viz and no current). But again, in semi closed mode, I can even loose the down line and finish my deco without problem.

What are you guys thinking about it ? Any risk I forgot to consider ?

jeez your an
accident waiting to happen.

get trained

PCDiver · 1st October 2006, 07:43

Quote: (Originally Posted by Drmike)

jeez your an
accident waiting to happen.

get trained

Perhaps he has more lives than you Dr Cat.

Seriously, based on my limited CCR experience I have learned the following:

Take enough bailout. Calculate high RMV at the bottom. Don't expect to be able to get off the bottom immediately. You will loose time trying to determine/fix the problem, get out of the wreck, swim back to the line, ...
Take the proper bailout, forget air.
Don't count on onboard, it can go really quickly.
Dive with a reliable and experienced CCR buddy. He will know what to do if you need help.
Build up your experience SLOWLY. Don't push it. Two 60 meter dives and asking the questions you are asking seems pushing it.
Don't rely on past OC experience. You will make the wrong choices when faced with a problem on CCR.

Pelagian · 1st October 2006, 14:47

Tx 20/40
EAN 50
O2

Take enough to complete absolute worst case bailout, presumably completed total bottom time slightly deeper than expected and then have to get off the loop.

I don't have any OC access to my on board gases, by design, so I don't factor that in.

Cheers

Seb

Gilles · 2nd October 2006, 14:23

Quote: (Originally Posted by Pelagian)

Tx 20/40
EAN 50
O2

Take enough to complete absolute worst case bailout, presumably completed total bottom time slightly deeper than expected and then have to get off the loop.

As above but on the 2nd dive on the day (will require more deco time than if you bail out on first dive).

If you need to bail on the 1st, you probably won't feel like a 2nd dive of the same scale on the same day. Also assume high RMV (30+)

Dawktah · 23rd October 2006, 20:57

Hello!

I am a newbie reading this thread with curiosity. I am considering switching to CCR. The course requires that you provide bailout bottles. Which size should I purchase if in the future I may dive CCR-deco? This thread contains many sizes. My current plan is to dive CCR-no stop. Deepest depth I'll encounter is 100 fsw unless I travel. In the distant future I will gradually move to deeper depths while still taking photos.

I have my own boat and will most likely have a buddy diving OC while diving max. depth of 100 fsw. Can you hang your bailout on your descent line and carry a smaller bailout (e.g. 13cf) to get to the larger bailout you hung if diving solo?? I am using CCR for photography and I am just wondering how you carry all the bailout bottles and a camera? Most importantly dive reef friendly and don't damage reef trying to take photos with a deco bottle(s)?

My cameras housing is rated to 200 feet. With room for "Murphy" my max. depth will be 180 feet max.

30th September 2006, 08:53	#31 (permalink)
divetheworld Dive porn pimp Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Classic Kiss Other CCR Join Date: Mar 2005 Location: Leeds, England Posts: 1,586	Re: Bailout Gases for long 60 metre dives Quote: (Originally Posted by decoweenie) I have a hypothetical question... If only 1% of the CCR dives resulted in requiring OC-bail-out from the bottom to surface, how many people would be willing to accept this risk for the sake of diving uncumbered without stages knowing that if they have a loop flood, they will die ? That means 1 in 100 dives, so could be a high percentage. So let's reduce to 0.5%, that means 1 complete loop flood in 200 dives. Or let's say 1 in 500 dives ? Remember it could happen anytime between dive 1 and 500.. Who would take this risk ? I know a few alpinist divers. Some are just lazy and complacent, but some are fully aware of the risk but willing to accept the percentage. I know you didn't ask about alpinist, but IMHO, there is no such thing as semi-alpinist (i.e. like semi pregnant) so either you have adequate OC bail-out or you don't. So having a small amount of off-board gas just to take "sanity breaths" is alpinist in my book. What would someone do when after taking a few sanity breaths, they realize that they can't get back on the loop and not having adequate OC-bail-out ? Back to the old chestnut of 'do you include inboard' in your bail plans or not? Personally, I conside OC bail to be 'last line of defence' so assume complete and catastrophic failure. If the inboard is in tact then its a bonus in the fact that I have some 100% for the 6m stop. The rest of the inboard is just sanity breath to the BOV. I tend to keep the He content of the primary bail the same as the Dil. How much bail is a matter of new debate for me. When my mate John had a Co2 hit, his RMV hit 90. I have to conclude that planning bail on normal to slightly elevated RMV is not the best idea. Brent. __________________ Attitude and self praise is no reccomendation. Dont try to be a great man, just be a man and let history be the judge of you. CHECK OUT OUR INTERWEBS FOR CUSTOM REBREATHER UPGRADES *WWW.NARKEDAT90.CO.UK* *http://www.grpservices.com/pursuit/* Supporting Shearwater Research Products in Europe Last edited by divetheworld : 30th September 2006 at 08:58.
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30th September 2006, 09:00	#32 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,487	Re: Bailout Gases for long 60 metre dives Quote: (Originally Posted by divetheworld) Back to the old chestnut... If the inboard is in tact then its a bonus in the fact that I have some 100% for the 6m stop. Speaking of old chestnut... Some people are concerned about the additional connection (to breath on-board O2 as OC) to be a potential failure source. If the loop is intact but all O2 is lost, then the unit is potentially useless (unless you could plumb in off-board deco gas = another connector failure source)... And so on, and so on... __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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30th September 2006, 09:06	#33 (permalink)
divetheworld Dive porn pimp Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Classic Kiss Other CCR Join Date: Mar 2005 Location: Leeds, England Posts: 1,586	Re: Bailout Gases for long 60 metre dives Quote: (Originally Posted by decoweenie) Speaking of old chestnut... Some people are concerned about the additional connection (to breath on-board O2 as OC) to be a potential failure source. If the loop is intact but all O2 is lost, then the unit is potentially useless (unless you could plumb in off-board deco gas = another connector failure source)... And so on, and so on... And they are right to give it consideration. I did. The Dil and O2 go to a gas switching block which feeds my BOV. It is default switched to the dil for sanity breaths. If I need it at 6m then a quick switch. If the BOV or GCS to the BOV fails then I only loose the dil. Ho hum. Failure of the pipework to the switch block or the switch block itself is an acceptable one to me. Then its off to the stages and out of the water sharpish. I dont think hanging a reg off the inboard o2 is a good idea without a flow stop. Even then, I prefer my way because the pipes are short and well protected in this little frame thing I have. Brent. your frame - GRP Services gas switching - GRP Services __________________ Attitude and self praise is no reccomendation. Dont try to be a great man, just be a man and let history be the judge of you. CHECK OUT OUR INTERWEBS FOR CUSTOM REBREATHER UPGRADES *WWW.NARKEDAT90.CO.UK* *http://www.grpservices.com/pursuit/* Supporting Shearwater Research Products in Europe Last edited by divetheworld : 30th September 2006 at 09:13.
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30th September 2006, 12:22	#34 (permalink)
pchanning PFO free :) Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: fixed! Posts: 454	Re: Bailout Gases for long 60 metre dives Quote: (Originally Posted by decoweenie) Speaking of old chestnut... Some people are concerned about the additional connection (to breath on-board O2 as OC) to be a potential failure source. If the loop is intact but all O2 is lost, then the unit is potentially useless (unless you could plumb in off-board deco gas = another connector failure source)... And so on, and so on... Exactly. I lost my o2 from the 1st stage (right at the end of the dive). So I carried redundant o2 from that point. I later had BOTH handsets go down (Inspo) on the bottom (however, I never bothered with a 4th cells as they were rubbish) and so on, and so on. But, it has to end somewhere... I have found that this 'counter culture', can be counter productive. I have seen a diver come unstuck (very deep) because of too many ideas and 'things' either getting in the way / badly configured. When it mattered, all the 'gear' was a real hindrance, not a help. That was where it ended for me (and him - nearly). I just carry OC and dive a clean unit. Life is simple and the diving all the more enjoyable for it. Maybe I am like the perverbeal (sp?) donkey that when faced with two bails of hay, ends up starving. Anyway, getting back to the thread title, the good thing about 3 optimised tins (which I have never tried) is that if one reg went wrong then it could be swopped out whilst staying OC. Which sounds quite sensible to me. Cheers Paul __________________ Cheers Paul The key to enlightenment... is survival. Last edited by pchanning : 30th September 2006 at 12:26. Reason: speelling ;)
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30th September 2006, 18:54	#35 (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: Bailout Gases for long 60 metre dives Quote: (Originally Posted by lbihler) Hi all, I m going on a Deep Virgin Wreck diving livaboard south thailand next week. I just can t figure out which gases I would take for bailout. I m quite a beginner on deep wreck dives and wanted your opinion before doing a fatal mistake. Profile is usually 60 metres for 40 minutes, 2 dives a day. Onboard I use 100% (98) and 14/44 trimix, 1.0 ppO2 bottom 1.4 ppO2 ascent for that mix. Knowing that they have O2 at will at 6 metres under the boat and that I can not really count on other divers as I will probably be the only CCR diver and as everybody tends to go solo. Last time I took 12litres Air and 12 litres 36% as bailout, which is enough for me to complete all my deco on OC. Thing is I ran out of O2 during the dive (stupid me, don t ask) with a fully functionning unit and had to ascent in semi closed, which took me ages to deco. Question is, what would you guys use, knowing that available gases are any mix below 40% O2 including air and trimix, and 100% O2 ? I was thinking about taking a 12litres Air at 200 bars and a 12litres 02 at about 100 bars (no booster on the boat) so that even if I work a bit at the bottom I have enough O2 to finish in fully closed and I can fly the unit manually and spare my back gas for emergencies. I ll be a bit short on OC ascent if the problem occurs at the end of the dive and I do not find the deco bars (not a probable case, brilliant viz and no current). But again, in semi closed mode, I can even loose the down line and finish my deco without problem. What are you guys thinking about it ? Any risk I forgot to consider ? jeez your an accident waiting to happen. get trained __________________ 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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1st October 2006, 07:43	#36 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 970	Re: Bailout Gases for long 60 metre dives Quote: (Originally Posted by Drmike) jeez your an accident waiting to happen. get trained Perhaps he has more lives than you Dr Cat. Seriously, based on my limited CCR experience I have learned the following: Take enough bailout. Calculate high RMV at the bottom. Don't expect to be able to get off the bottom immediately. You will loose time trying to determine/fix the problem, get out of the wreck, swim back to the line, ... Take the proper bailout, forget air. Don't count on onboard, it can go really quickly. Dive with a reliable and experienced CCR buddy. He will know what to do if you need help. Build up your experience SLOWLY. Don't push it. Two 60 meter dives and asking the questions you are asking seems pushing it. Don't rely on past OC experience. You will make the wrong choices when faced with a problem on CCR.
(Online)

1st October 2006, 14:47	#37 (permalink)
Pelagian Multi-Circuit Meg Monkey! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Optima Join Date: Feb 2005 Location: Leeds, England Posts: 282	Re: Bailout Gases for long 60 metre dives Tx 20/40 EAN 50 O2 Take enough to complete absolute worst case bailout, presumably completed total bottom time slightly deeper than expected and then have to get off the loop. I don't have any OC access to my on board gases, by design, so I don't factor that in. Cheers Seb __________________ 'Because... I was Inverted!'
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2nd October 2006, 14:23	#38 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: Bailout Gases for long 60 metre dives Quote: (Originally Posted by Pelagian) Tx 20/40 EAN 50 O2 Take enough to complete absolute worst case bailout, presumably completed total bottom time slightly deeper than expected and then have to get off the loop. As above but on the 2nd dive on the day (will require more deco time than if you bail out on first dive). If you need to bail on the 1st, you probably won't feel like a 2nd dive of the same scale on the same day. Also assume high RMV (30+) __________________ Gilles http://www.dirrebreather.com
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23rd October 2006, 20:57	#39 (permalink)
Dawktah New Member Current Rebreather/s: Inspiration Vision Evolution Other Rebreather/s: Join Date: Sep 2006 Location: Chicago Posts: 38	Re: Bailout Gases for long 60 metre dives Hello! I am a newbie reading this thread with curiosity. I am considering switching to CCR. The course requires that you provide bailout bottles. Which size should I purchase if in the future I may dive CCR-deco? This thread contains many sizes. My current plan is to dive CCR-no stop. Deepest depth I'll encounter is 100 fsw unless I travel. In the distant future I will gradually move to deeper depths while still taking photos. I have my own boat and will most likely have a buddy diving OC while diving max. depth of 100 fsw. Can you hang your bailout on your descent line and carry a smaller bailout (e.g. 13cf) to get to the larger bailout you hung if diving solo?? I am using CCR for photography and I am just wondering how you carry all the bailout bottles and a camera? Most importantly dive reef friendly and don't damage reef trying to take photos with a deco bottle(s)? My cameras housing is rated to 200 feet. With room for "Murphy" my max. depth will be 180 feet max. Last edited by Dawktah : 23rd October 2006 at 21:01.
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