Standard Bailout Mixes

PCDiver · 3rd September 2007, 17:26

Quote: (Originally Posted by Fun Under Pressure)

i think standards gases don´t bring any benefit. The DIR guy´s use it to have the best END´s and MOD´s . But for my (only air diluent dive´s at this time) a use gases that i can breath at my max. deep.
Ali 80 21/00 ; Ali 80 50/00 ; Ali 7L 100/00

For deeper dive´s i think one bailout tank with a gas i can breathe at the MOD and one or two tank´s for deco on OC and one tank with 100 % for last deco. I think that´s a lot of tanks, and i must do any training dive´s befor i do deeper dive´s, but i have children´s and the safety is importend for me.

Cheers Markku

Markku,

That's a lot of bailout gas. What kind of depths, bottom times are you talking about? Don't forget that schlepping too many tanks with you can also cause problems.

Peter

***jradomski*** · 3rd September 2007, 19:01

Quote: (Originally Posted by wedivebc)

So are you concerned that a cell can current limit during a dive and therefore must be validated regularly even though it made 1.6 at the start of a dive?
What I am reading here is you select your gas on the basis of cell validation ability. In my mind other than validating the cells at a known gas pressure to ensure they are all still functioning I can't see why a high PO2 flush is needed. I was not aware cells would drop out at the high end that fast.

Fisrt of all.. yes than can drop out during a dive and If I believe their may be an issue that forces me to validate them I should be able to properly validate them.. They act just like batteries.. early on they can work fine since they get a recovery just like a regular battery.. It may not happen often, but one time is enough for me.. Like I said.. If something makes you think you have to validate them, then you have to do it.. Validating to a low po2 only validates it to that po2..

Also in practice how many people actually test their cells to a 1.6 at the start of the dive.. alot of people have good intentions but I have RARELY seen it done consistently even by divers who swear they do it..

and 2 its not only for cell verification, a low fo2 mix makes a poor oc bailout gas than can significanly increase the required deco.. especially for those that have been taught to carry bottom breathable gas and oxygen.. Look at the number I posed for a simple 60m 45 minute dive.. Someone carrying just a "10/50" mix and Oxygen bailing to OC probably wount make it unless lots of extra gas can be brought to him/her.. Personally I rather plan for as many contingencies as I can instead of relying that things work as designed and if on choice can cover 2 failure modes, all the better..

kieranu · 4th September 2007, 00:52

Quote: (Originally Posted by jradomski)

and 2 its not only for cell verification, a low fo2 mix makes a poor oc bailout gas than can significanly increase the required deco.. especially for those that have been taught to carry bottom breathable gas and oxygen.. Look at the number I posed for a simple 60m 45 minute dive.. Someone carrying just a "10/50" mix and Oxygen bailing to OC probably wount make it unless lots of extra gas can be brought to him/her.. Personally I rather plan for as many contingencies as I can instead of relying that things work as designed and if on choice can cover 2 failure modes, all the better..

Indeed, again still a virgin so got my theoretical hat on, but I think these three of JonO's standard bailout gases would be best-suited for such a dive.

100%
50%
30/20ish
21/35
18/45
12/62

Or if you're game and assuming you have a clear path to the surface, you could possibly dispense with the 21/35 and have a BOV / second-stage on the onboard. Bailing to 10/50 and 100 also doesn't seem like a viable option to me unless additional gases can be dropped down.

Joe · 4th September 2007, 03:14

My preference is for appropriate bailout gas plus 50/50 for deco gas. Were you to bail out in the given scenario and you used a set point similar to an OC bottom mix PO2, the profile would be about the same as on OC as would the total run be about the same. IMO 50/50 is much more versatile than the O2 in that you can get on it deeper. This not only aids in your deco but also provides a bit of redundancy for deeper bailouts in that you don't have to wait to 20 feet to use it.

Given a choice, rather than carry the extra bottle for O2 I'd prefer a greater reserve of 50/50

Quote: (Originally Posted by kieranu)

Indeed, again still a virgin so got my theoretical hat on, but I think these three of JonO's standard bailout gases would be best-suited for such a dive.

100%
50%
30/20ish
21/35
18/45
12/62

Bailing to 10/50 and 100 also doesn't seem like a viable option to me unless additional gases can be dropped down.

JS1scuba · 4th September 2007, 04:24

You could always take a page from the USN Mixed Gas Manual for diving the MK15 or MK16 fly a set point of .70 PO2 and you can bail to air and have a pretty close decompression.

Run some scenarios and you will see you are very close........ and LONG.

For dives shallower than 150 fsw I'm carrying a bailout gas that gives me an MOD of about 1/2 my max depth. For dives deeper than 150 fsw i'm carring a 40 of a mix that's as close to 21% as possible with 1/2 the helium of the diluent and then something in the 50-60% ean range.

I have a few sets of bail out tables in my pocket and pull one if needed. But, I have run two Cochrans side by side one on OC the other on CCR and they do match up close to my carry gases so i am pretty comfortable just bailing to my OC gas and flying the puter. I don't carry O2 with me as bail out mostly because its pretty limited and we drop surface supply O2 from our boats so i always have that should I want to supplement the deco.

Cheers

JDS

***jradomski*** · 4th September 2007, 04:35

Quote: (Originally Posted by kieranu)

Indeed, again still a virgin so got my theoretical hat on, but I think these three of JonO's standard bailout gases would be best-suited for such a dive.

100%
50%
30/20ish
21/35
18/45
12/62

Or if you're game and assuming you have a clear path to the surface, you could possibly dispense with the 21/35 and have a BOV / second-stage on the onboard. Bailing to 10/50 and 100 also doesn't seem like a viable option to me unless additional gases can be dropped down.

My whole reason for discussing the 10/50 and o2 combination is that there are many CCR divers trained this way.. I run into all the time.. I usually try and point out the benefit of 50% over o2 but they say they were trained to carry oxygen, I know I would never dive that combination..

50% gives you lots of options, and you can generally keep a balanced bailout of bottom and deco gases.. O2 realy isnt needed and is a limited use gas.. On really big dives, I'll add a 3rd bottle, which is usually a normoxic mix.. SO that I end up with a breathable deep mix, and intermediate trimix for 60m up, then finally 50%...

then as long as the loop is intact, I'd switch to an o2 rebreather at 6m and switching back to the 50% for low(er) fo2 breaks..

JonORunde · 4th September 2007, 08:20

Quote: (Originally Posted by jradomski)

My whole reason for discussing the 10/50 and o2 combination is that there are many CCR divers trained this way.. I run into all the time.. I usually try and point out the benefit of 50% over o2 but they say they were trained to carry oxygen, I know I would never dive that combination..

I bring O2 for one reason -I dive a COPIS, and when the internal O2-1.stage stops working, my s40 of O2 is plugged into the manual O2-add, and gives me O2 at depth -which is a good thing

Up to that depth, 50% in normally chosen.

jon o

***jradomski*** · 4th September 2007, 08:37

Quote: (Originally Posted by JonORunde)

I bring O2 for one reason -I dive a COPIS, and when the internal O2-1.stage stops working, my s40 of O2 is plugged into the manual O2-add, and gives me O2 at depth -which is a good thing

Up to that depth, 50% in normally chosen.

jon o

You can maintain the loop with 50% quite well, plus then you gain a gas you can use over a much wider range of depths.. IF you really want o2 for that purpose a small .5 to1l bottle is more than enough and takes up virtually no space..

JonORunde · 4th September 2007, 10:00

Quote: (Originally Posted by jradomski)

You can maintain the loop with 50% quite well, plus then you gain a gas you can use over a much wider range of depths.. IF you really want o2 for that purpose a small .5 to1l bottle is more than enough and takes up virtually no space..

I probably could, but I like it this way.
It is easy to work with the s40, clipping on/off, giving to a buddy if needed, and to use OC as deco-gas. In addition of course to other decogases.
And I almost do not use any O2 when diving, so my 3-liters works forever!

jon o

KevDD · 4th September 2007, 11:45

I can see the point of gas matching with your regular dive buddies just incase there is a bailout then you know what gas your buddy has and it matches your own.

Personally i wouldn't drain a cylinder to blend an optimal bailout mix for each dive. That would be a crazy waste of helium! I blended my deep bailout 8 months ago and other than i had to bailout as a skill on a course it would still be the same gas no matter if i was on a 40m or 90m dive.

Once i have enough volume of gas to get me to the deco station without doing a polaris I'm pretty happy as there will either be gas hanging on the station (O2 at 6m) waiting for me or other divers coming back to the station all carrying bailout.

i know in an ideal world we would all be blending gases to give us the best deco profile before every dive but thats an ideal world. I live in the real world.

3rd September 2007, 17:26	#51 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 968	Re: Standard Bailout Mixes Quote: (Originally Posted by Fun Under Pressure) i think standards gases don´t bring any benefit. The DIR guy´s use it to have the best END´s and MOD´s . But for my (only air diluent dive´s at this time) a use gases that i can breath at my max. deep. Ali 80 21/00 ; Ali 80 50/00 ; Ali 7L 100/00 For deeper dive´s i think one bailout tank with a gas i can breathe at the MOD and one or two tank´s for deco on OC and one tank with 100 % for last deco. I think that´s a lot of tanks, and i must do any training dive´s befor i do deeper dive´s, but i have children´s and the safety is importend for me. Cheers Markku Markku, That's a lot of bailout gas. What kind of depths, bottom times are you talking about? Don't forget that schlepping too many tanks with you can also cause problems. Peter
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3rd September 2007, 19:01	#52 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,001	Re: Standard Bailout Mixes Quote: (Originally Posted by wedivebc) So are you concerned that a cell can current limit during a dive and therefore must be validated regularly even though it made 1.6 at the start of a dive? What I am reading here is you select your gas on the basis of cell validation ability. In my mind other than validating the cells at a known gas pressure to ensure they are all still functioning I can't see why a high PO2 flush is needed. I was not aware cells would drop out at the high end that fast. Fisrt of all.. yes than can drop out during a dive and If I believe their may be an issue that forces me to validate them I should be able to properly validate them.. They act just like batteries.. early on they can work fine since they get a recovery just like a regular battery.. It may not happen often, but one time is enough for me.. Like I said.. If something makes you think you have to validate them, then you have to do it.. Validating to a low po2 only validates it to that po2.. Also in practice how many people actually test their cells to a 1.6 at the start of the dive.. alot of people have good intentions but I have RARELY seen it done consistently even by divers who swear they do it.. and 2 its not only for cell verification, a low fo2 mix makes a poor oc bailout gas than can significanly increase the required deco.. especially for those that have been taught to carry bottom breathable gas and oxygen.. Look at the number I posed for a simple 60m 45 minute dive.. Someone carrying just a "10/50" mix and Oxygen bailing to OC probably wount make it unless lots of extra gas can be brought to him/her.. Personally I rather plan for as many contingencies as I can instead of relying that things work as designed and if on choice can cover 2 failure modes, all the better.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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4th September 2007, 00:52	#53 (permalink)
kieranu Apprentice Meg Pilot Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: WA, Australia Posts: 235	Re: Standard Bailout Mixes Quote: (Originally Posted by jradomski) and 2 its not only for cell verification, a low fo2 mix makes a poor oc bailout gas than can significanly increase the required deco.. especially for those that have been taught to carry bottom breathable gas and oxygen.. Look at the number I posed for a simple 60m 45 minute dive.. Someone carrying just a "10/50" mix and Oxygen bailing to OC probably wount make it unless lots of extra gas can be brought to him/her.. Personally I rather plan for as many contingencies as I can instead of relying that things work as designed and if on choice can cover 2 failure modes, all the better.. Indeed, again still a virgin so got my theoretical hat on, but I think these three of JonO's standard bailout gases would be best-suited for such a dive. 100% 50% 30/20ish 21/35 18/45 12/62 Or if you're game and assuming you have a clear path to the surface, you could possibly dispense with the 21/35 and have a BOV / second-stage on the onboard. Bailing to 10/50 and 100 also doesn't seem like a viable option to me unless additional gases can be dropped down. Last edited by kieranu : 4th September 2007 at 03:02. Reason: Onboard option
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4th September 2007, 03:14	#54 (permalink)
Joe Custom Title Allowed! Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Oct 2005 Location: Florida, USA Posts: 271	Re: Standard Bailout Mixes My preference is for appropriate bailout gas plus 50/50 for deco gas. Were you to bail out in the given scenario and you used a set point similar to an OC bottom mix PO2, the profile would be about the same as on OC as would the total run be about the same. IMO 50/50 is much more versatile than the O2 in that you can get on it deeper. This not only aids in your deco but also provides a bit of redundancy for deeper bailouts in that you don't have to wait to 20 feet to use it. Given a choice, rather than carry the extra bottle for O2 I'd prefer a greater reserve of 50/50 Quote: (Originally Posted by kieranu) Indeed, again still a virgin so got my theoretical hat on, but I think these three of JonO's standard bailout gases would be best-suited for such a dive. 100% 50% 30/20ish 21/35 18/45 12/62 Bailing to 10/50 and 100 also doesn't seem like a viable option to me unless additional gases can be dropped down.
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4th September 2007, 04:24	#55 (permalink)
JS1scuba RebreatherWorld Sponsor Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Classic Kiss MK 15.X Join Date: Oct 2005 Location: Lake Havasu City, AZ - USA Posts: 511	Re: Standard Bailout Mixes You could always take a page from the USN Mixed Gas Manual for diving the MK15 or MK16 fly a set point of .70 PO2 and you can bail to air and have a pretty close decompression. Run some scenarios and you will see you are very close........ and LONG. For dives shallower than 150 fsw I'm carrying a bailout gas that gives me an MOD of about 1/2 my max depth. For dives deeper than 150 fsw i'm carring a 40 of a mix that's as close to 21% as possible with 1/2 the helium of the diluent and then something in the 50-60% ean range. I have a few sets of bail out tables in my pocket and pull one if needed. But, I have run two Cochrans side by side one on OC the other on CCR and they do match up close to my carry gases so i am pretty comfortable just bailing to my OC gas and flying the puter. I don't carry O2 with me as bail out mostly because its pretty limited and we drop surface supply O2 from our boats so i always have that should I want to supplement the deco. Cheers JDS __________________ Joel Silverstein, VP COO Tech Diving Limited a Division of Scuba Training and Technology Inc. http://www.nautilusdiveplanner.com http://www.nobubblediving.com Last edited by JS1scuba : 4th September 2007 at 04:39.
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4th September 2007, 04:35	#56 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,001	Re: Standard Bailout Mixes Quote: (Originally Posted by kieranu) Indeed, again still a virgin so got my theoretical hat on, but I think these three of JonO's standard bailout gases would be best-suited for such a dive. 100% 50% 30/20ish 21/35 18/45 12/62 Or if you're game and assuming you have a clear path to the surface, you could possibly dispense with the 21/35 and have a BOV / second-stage on the onboard. Bailing to 10/50 and 100 also doesn't seem like a viable option to me unless additional gases can be dropped down. My whole reason for discussing the 10/50 and o2 combination is that there are many CCR divers trained this way.. I run into all the time.. I usually try and point out the benefit of 50% over o2 but they say they were trained to carry oxygen, I know I would never dive that combination.. 50% gives you lots of options, and you can generally keep a balanced bailout of bottom and deco gases.. O2 realy isnt needed and is a limited use gas.. On really big dives, I'll add a 3rd bottle, which is usually a normoxic mix.. SO that I end up with a breathable deep mix, and intermediate trimix for 60m up, then finally 50%... then as long as the loop is intact, I'd switch to an o2 rebreather at 6m and switching back to the 50% for low(er) fo2 breaks.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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4th September 2007, 08:20	#57 (permalink)
JonORunde New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2005 Location: Norway Posts: 88	Re: Standard Bailout Mixes Quote: (Originally Posted by jradomski) My whole reason for discussing the 10/50 and o2 combination is that there are many CCR divers trained this way.. I run into all the time.. I usually try and point out the benefit of 50% over o2 but they say they were trained to carry oxygen, I know I would never dive that combination.. I bring O2 for one reason -I dive a COPIS, and when the internal O2-1.stage stops working, my s40 of O2 is plugged into the manual O2-add, and gives me O2 at depth -which is a good thing Up to that depth, 50% in normally chosen. jon o
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4th September 2007, 08:37	#58 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,001	Re: Standard Bailout Mixes Quote: (Originally Posted by JonORunde) I bring O2 for one reason -I dive a COPIS, and when the internal O2-1.stage stops working, my s40 of O2 is plugged into the manual O2-add, and gives me O2 at depth -which is a good thing Up to that depth, 50% in normally chosen. jon o You can maintain the loop with 50% quite well, plus then you gain a gas you can use over a much wider range of depths.. IF you really want o2 for that purpose a small .5 to1l bottle is more than enough and takes up virtually no space.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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4th September 2007, 10:00	#59 (permalink)
JonORunde New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2005 Location: Norway Posts: 88	Re: Standard Bailout Mixes Quote: (Originally Posted by jradomski) You can maintain the loop with 50% quite well, plus then you gain a gas you can use over a much wider range of depths.. IF you really want o2 for that purpose a small .5 to1l bottle is more than enough and takes up virtually no space.. I probably could, but I like it this way. It is easy to work with the s40, clipping on/off, giving to a buddy if needed, and to use OC as deco-gas. In addition of course to other decogases. And I almost do not use any O2 when diving, so my 3-liters works forever! jon o
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4th September 2007, 11:45	#60 (permalink)
KevDD Custom Title Allowed! Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Oct 2005 Location: Dublin, Ireland Posts: 99	Re: Standard Bailout Mixes I can see the point of gas matching with your regular dive buddies just incase there is a bailout then you know what gas your buddy has and it matches your own. Personally i wouldn't drain a cylinder to blend an optimal bailout mix for each dive. That would be a crazy waste of helium! I blended my deep bailout 8 months ago and other than i had to bailout as a skill on a course it would still be the same gas no matter if i was on a 40m or 90m dive. Once i have enough volume of gas to get me to the deco station without doing a polaris I'm pretty happy as there will either be gas hanging on the station (O2 at 6m) waiting for me or other divers coming back to the station all carrying bailout. i know in an ideal world we would all be blending gases to give us the best deco profile before every dive but thats an ideal world. I live in the real world.
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