VR£ Bailout gases - is it OK to leave them ON all the time?!!

Mdemon · 8th May 2005, 13:59

Switching on gases so you can select them seems to be just a bit more work than I really want to be doing having bailed out. Reading through the manual, I am getting the impression that if I leave my OC bailout gases switched On, although it will screw the Prediction, the actual deco will be correct.

So, the theory is to leave e.g. 10/52, 18/35, 60% and 99% switched ON all the time. On the understanding that I never plan dives on the VR£ but on my laptop, am I right in thinking my usual CCR deco will be correct and if I bailout, my OC deco will also be correct?

So, my loop floods...

To go OC:
Long Left Click
Long Both (goto OC)
Short LC (scroll through gas list)
Short RC (select Gas and return to main screen on OC)

To choose next OC gas manually:
Long LC
Short LC (scroll through gas list)
Short RC (select Gas and return to main screen on OC)

Still a lot of buttons, but I think less effort than switching 3 gasses on...

New to VR£ - any thoughts on this please?

From the VR£ manual...

Quote:

The VR3 assumes that the P02 selected is the P02 that the rebreather will
maintain as its setpoint during the dive and it will calculate decompression
based on this and the diluent set.

Example
A Trimix rebreather dive is planned with 18/35 as the diluent. The diver
will use closed circuit Trimix throughout and then switch to open circuit
surface-supplied oxygen at the 6m stop. In the event that an open circuit
bailout is required the diver plans to carry an 18/35 cylinder and a Nitrox
36 cylinder. 18/35, Nitrox 36 and oxygen are selected as the three gases.
The Nitrox 36 and oxygen remain OFF leaving Trimix 18/35 as the only
ON gas. This will be seen as the DIL when the diver chooses the
CLOSED CCT screen. In the CLOSED CCT screen the diver selects a
P02 of 0.7 for the start of the dive, then exits and re-enters the screen to
select a second P02 setpoint of 1.3 which can then be switched to at
depth.
If the diver were to leave 36 and 02 ON then they would be factored into
the decompression prediction. Having said this, even if they were left ON
accidentally the actual decompression would still be based on the gas
selected as the DIL. In other words the prediction would be wrong but the
actual decompression would be correct.
In the event of an Open Circuit bailout becoming necessary all three
gases are now available as Open Circuit gases but must be turned ON to
obtain an accurate prediction. Setting the MODs correctly will
automatically trigger prompts for the correct gas switches as the diver
ascends.

(EDIT: 10/52, 18/35, 60% and 99% chosen as I have access to all these gases - the middle two being the gasses I'd plan to use for bailout, the others for last-gasp bailout.)

Mark Chase · 8th May 2005, 15:52

To the best of my knowledge you can’t do this. If you do the VR3 will assume that you’re switching dills throughout the dive and calculate the deco accordingly.

I tried it with Profiles as well but that didn’t work well either

A single push button bail out option was requested in writing by Dave Shaw but as far as I am aware DeltaP have not addressed the issue.

ATB

Mark Chase

***Decodiver*** · 8th May 2005, 15:59

As far as I know you should only have the current Diluent switched on.

I put the bailouts adjacent to my current Dil.

Leftside mix before it and rightside mix after it.

Yes it is a pain in the jacksie, but no-one ever said it was going to be easy......

Cheers,

Dave Cooper

Mdemon · 8th May 2005, 16:35

Mark, I can't see it changing Dils without asking - it doesn't on OC?

I wonder if Delta P will respond...

I have my gases Hardest through to deco (99%) - each switch is just another click away...

Padowan · 8th May 2005, 16:48

If you leave more than one gas on, then the VR3 will assume that you are going to switch diluent to each gas at your specified MODs. The TTS that the VR3 will give you will be based on this presumption. HOWEVER, until you switch to each gas the rate that the TTS drops taken into account the CURRENT gas, so you may see a TTS of 30 mins, but it might take 45 mins to clear, even if you change stops exactly when it tells you.

NOW, if you have planned your bailout gasses well, such that you are optimising PPO2 and keeping a constant PPN2 during each switch, then my theory goes that each time that the VR3 thinks you are switching Dil, the resultant PPO2, N2 and He are pretty much constant throughout the ascent (ie, 1.3bar PPO2 and the remainder split correctly between the inerts) so the ascent times should tally quite closely. If you're a bad man, and you do tell it that you're doing silly things like switch to air dil at 50m or something the profiles will be further apart - but we all know that diluent switches from high He to high N2 mixes is bad so we'd never do that right...?!.

Caveat - I've not run any of this through the VR3, it's just from my understanding of how it works.

Mark Chase · 8th May 2005, 17:07

Quote: (Originally Posted by Mdemon)

Mark, I can't see it changing Dils without asking - it doesn't on OC?

..

Yes it does.

You have to confirm the dill switches but it will auto switch and it will calculate deco on all available (ie ON) diluents or OC gases

ATB

Mark Chase

Mdemon · 8th May 2005, 17:23

Quote: (Originally Posted by Padowan)

If you leave more than one gas on, then the VR3 will assume that you are going to switch diluent to each gas at your specified MODs. .

How do you know this? Does it show this in the manual? The quote suggests otherwise...

As you say, if you use the right gasses that looks quite positive. I guess I can do a dive on tables and see what the VR£ tells me. I can't see it switching without asking as per OC though. As the manual (and you) points out, the VR£ uses the actual dil for calculating, so if you can ignore the TTS and just run as per the stops and the diver on the wire, it should work...

Anyone else able to add anything, before I fire off e-mails to DeltaP?

Mdemon · 8th May 2005, 17:27

Quote: (Originally Posted by Mark Chase)

Yes it does.

You have to confirm the dill switches but it will auto switch and it will calculate deco on all available (ie ON) diluents or OC gases

ATB

Mark Chase

Sorry Mark, you squeezed that in while I was posting!

Have you seen this work? Or could you point me to the bit in the manual which explains this please? Shame, it was a nice idea...

Mark Chase · 8th May 2005, 17:51

Quote: (Originally Posted by Mdemon)

Sorry Mark, you squeezed that in while I was posting!

Have you seen this work? Or could you point me to the bit in the manual which explains this please? Shame, it was a nice idea...

No this is from experience on OC. As previously posted it will show TTS based on all ON gasses but unless you confirm the switch it won’t count down deco on the TTS figure. I haven’t tried multiple diluents on CCR yet so I don’t know how it works on that level. I did a diluient switch on CCR in the red sea but as it was an off the cuff decision I manually altered the gas during deco. Quite interesting results I must say

ATB

Mark Chase

Andy Del · 8th May 2005, 20:56

Quote: (Originally Posted by Mark Chase)

Yes it does.

You have to confirm the dill switches but it will auto switch and it will calculate deco on all available (ie ON) diluents or OC gases

ATB

Mark Chase

Ah, actually no it will not. Sorry but there's no auto switching at all on a VR3. All switches have to be confirmed manually. You'll get an alert to change gas at your MOD on ascent (and descent too if you look) but it won't alter the gas form you.

We can all blame a manual written in 'English' instead of 'English' (if you get my drift) as it is as poorly written as anything translated from SE Asia. Even after following through with requests for manual corrections, it's simply dense. Another major problem is that while customer service is quite nice and prompt, especially via email, they don't seem to be able to answer specific questions with concise answers.

Simply put, a VR3 will not calculate your you real time deco during a dive on anything bar what you have selected as the breathing gas. It will predict your deco time for all gasses which are ON at the time, but I don't se how you can run the dive planner in CC mode for bottom time and OC mode for bailout ascent.

It does use all gases set to ON when in dive plan mode. It won't use more than 1 PO2 in dive plan mode that I have been able to see.

It depends on what you like to see during the dive. I like to have a vague idea of how long and ascent I have to do, so the TTS figure is important to me. I carry bailout tables in case I have no computer to work from, or I can't afford the time to change settings. These would take about 20 seconds? (Someone needs to time this!)

I think if one sets out all the options, it look like a VR3 is great OC, great CC, but not so pliable in a CC dive with OC bailout and high task loading. Maybe this is something to do while at work today...

8th May 2005, 13:59	#1 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,927	VR£ Bailout gases - is it OK to leave them ON all the time?!! Switching on gases so you can select them seems to be just a bit more work than I really want to be doing having bailed out. Reading through the manual, I am getting the impression that if I leave my OC bailout gases switched On, although it will screw the Prediction, the actual deco will be correct. So, the theory is to leave e.g. 10/52, 18/35, 60% and 99% switched ON all the time. On the understanding that I never plan dives on the VR£ but on my laptop, am I right in thinking my usual CCR deco will be correct and if I bailout, my OC deco will also be correct? So, my loop floods... To go OC: Long Left Click Long Both (goto OC) Short LC (scroll through gas list) Short RC (select Gas and return to main screen on OC) To choose next OC gas manually: Long LC Short LC (scroll through gas list) Short RC (select Gas and return to main screen on OC) Still a lot of buttons, but I think less effort than switching 3 gasses on... New to VR£ - any thoughts on this please? From the VR£ manual... Quote: The VR3 assumes that the P02 selected is the P02 that the rebreather will maintain as its setpoint during the dive and it will calculate decompression based on this and the diluent set. Example A Trimix rebreather dive is planned with 18/35 as the diluent. The diver will use closed circuit Trimix throughout and then switch to open circuit surface-supplied oxygen at the 6m stop. In the event that an open circuit bailout is required the diver plans to carry an 18/35 cylinder and a Nitrox 36 cylinder. 18/35, Nitrox 36 and oxygen are selected as the three gases. The Nitrox 36 and oxygen remain OFF leaving Trimix 18/35 as the only ON gas. This will be seen as the DIL when the diver chooses the CLOSED CCT screen. In the CLOSED CCT screen the diver selects a P02 of 0.7 for the start of the dive, then exits and re-enters the screen to select a second P02 setpoint of 1.3 which can then be switched to at depth. If the diver were to leave 36 and 02 ON then they would be factored into the decompression prediction. Having said this, even if they were left ON accidentally the actual decompression would still be based on the gas selected as the DIL. In other words the prediction would be wrong but the actual decompression would be correct. In the event of an Open Circuit bailout becoming necessary all three gases are now available as Open Circuit gases but must be turned ON* to* obtain an accurate prediction. Setting the MODs correctly will automatically trigger prompts for the correct gas switches as the diver ascends. (EDIT: 10/52, 18/35, 60% and 99% chosen as I have access to all these gases - the middle two being the gasses I'd plan to use for bailout, the others for last-gasp bailout.) __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"
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8th May 2005, 15:52	#2 (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: 2,699	To the best of my knowledge you can’t do this. If you do the VR3 will assume that you’re switching dills throughout the dive and calculate the deco accordingly. I tried it with Profiles as well but that didn’t work well either A single push button bail out option was requested in writing by Dave Shaw but as far as I am aware DeltaP have not addressed the issue. 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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8th May 2005, 15:59	#3 (permalink)
*Decodiver* Administrator Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jan 2005 Location: Geneva Posts: 2,181	As far as I know you should only have the current Diluent switched on. I put the bailouts adjacent to my current Dil. Leftside mix before it and rightside mix after it. Yes it is a pain in the jacksie, but no-one ever said it was going to be easy...... 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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8th May 2005, 16:35	#4 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,927	Mark, I can't see it changing Dils without asking - it doesn't on OC? I wonder if Delta P will respond... I have my gases Hardest through to deco (99%) - each switch is just another click away... __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"
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8th May 2005, 16:48	#5 (permalink)
Padowan Proper Boffin Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Kent, UK. Posts: 518	If you leave more than one gas on, then the VR3 will assume that you are going to switch diluent to each gas at your specified MODs. The TTS that the VR3 will give you will be based on this presumption. HOWEVER, until you switch to each gas the rate that the TTS drops taken into account the CURRENT gas, so you may see a TTS of 30 mins, but it might take 45 mins to clear, even if you change stops exactly when it tells you. NOW, if you have planned your bailout gasses well, such that you are optimising PPO2 and keeping a constant PPN2 during each switch, then my theory goes that each time that the VR3 thinks you are switching Dil, the resultant PPO2, N2 and He are pretty much constant throughout the ascent (ie, 1.3bar PPO2 and the remainder split correctly between the inerts) so the ascent times should tally quite closely. If you're a bad man, and you do tell it that you're doing silly things like switch to air dil at 50m or something the profiles will be further apart - but we all know that diluent switches from high He to high N2 mixes is bad so we'd never do that right...?!. Caveat - I've not run any of this through the VR3, it's just from my understanding of how it works. __________________ Padowan The future's bright, the future's Yellow .....for now padowan.net - Latest Video: Scapa Flow Rebreather Diving
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8th May 2005, 17:07	#6 (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: 2,699	Quote: (Originally Posted by Mdemon) Mark, I can't see it changing Dils without asking - it doesn't on OC? .. Yes it does. You have to confirm the dill switches but it will auto switch and it will calculate deco on all available (ie ON) diluents or OC gases 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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8th May 2005, 17:23	#7 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,927	Quote: (Originally Posted by Padowan) If you leave more than one gas on, then the VR3 will assume that you are going to switch diluent to each gas at your specified MODs. . How do you know this? Does it show this in the manual? The quote suggests otherwise... As you say, if you use the right gasses that looks quite positive. I guess I can do a dive on tables and see what the VR£ tells me. I can't see it switching without asking as per OC though. As the manual (and you) points out, the VR£ uses the actual dil for calculating, so if you can ignore the TTS and just run as per the stops and the diver on the wire, it should work... Anyone else able to add anything, before I fire off e-mails to DeltaP? __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"
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8th May 2005, 17:27	#8 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,927	Quote: (Originally Posted by Mark Chase) Yes it does. You have to confirm the dill switches but it will auto switch and it will calculate deco on all available (ie ON) diluents or OC gases ATB Mark Chase Sorry Mark, you squeezed that in while I was posting! Have you seen this work? Or could you point me to the bit in the manual which explains this please? Shame, it was a nice idea... __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"
(Offline)

8th May 2005, 17:51	#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: 2,699	Quote: (Originally Posted by Mdemon) Sorry Mark, you squeezed that in while I was posting! Have you seen this work? Or could you point me to the bit in the manual which explains this please? Shame, it was a nice idea... No this is from experience on OC. As previously posted it will show TTS based on all ON gasses but unless you confirm the switch it won’t count down deco on the TTS figure. I haven’t tried multiple diluents on CCR yet so I don’t know how it works on that level. I did a diluient switch on CCR in the red sea but as it was an off the cuff decision I manually altered the gas during deco. Quite interesting results I must say 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)

8th May 2005, 20:56	#10 (permalink)
Andy Del Classic KISSer Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: Australia, Sunny Sydney Posts: 422	Quote: (Originally Posted by Mark Chase) Yes it does. You have to confirm the dill switches but it will auto switch and it will calculate deco on all available (ie ON) diluents or OC gases ATB Mark Chase Ah, actually no it will not. Sorry but there's no auto switching at all on a VR3. All switches have to be confirmed manually. You'll get an alert to change gas at your MOD on ascent (and descent too if you look) but it won't alter the gas form you. We can all blame a manual written in 'English' instead of 'English' (if you get my drift) as it is as poorly written as anything translated from SE Asia. Even after following through with requests for manual corrections, it's simply dense. Another major problem is that while customer service is quite nice and prompt, especially via email, they don't seem to be able to answer specific questions with concise answers. Simply put, a VR3 will not calculate your you real time deco during a dive on anything bar what you have selected as the breathing gas. It will predict your deco time for all gasses which are ON at the time, but I don't se how you can run the dive planner in CC mode for bottom time and OC mode for bailout ascent. It does use all gases set to ON when in dive plan mode. It won't use more than 1 PO2 in dive plan mode that I have been able to see. It depends on what you like to see during the dive. I like to have a vague idea of how long and ascent I have to do, so the TTS figure is important to me. I carry bailout tables in case I have no computer to work from, or I can't afford the time to change settings. These would take about 20 seconds? (Someone needs to time this!) I think if one sets out all the options, it look like a VR3 is great OC, great CC, but not so pliable in a CC dive with OC bailout and high task loading. Maybe this is something to do while at work today... __________________ Yellow - the colour of greatness!
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