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

Mdemon · 8th May 2005, 23:46

Thanks for your post, Andy.

Quote: (Originally Posted by Andy Del)

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..

OK, have I got this straight? The VR3, in CCR mode, will assume all I am breathing is the dil I have selected, regardless of the other gasses I have switched on?

And if the answer is yes, then will the TTS be correct and show correct if I continue as CCR?

Final question (prepared to be slagged for being thick, but it's late and I'm a bit slow...) - if I switch to OC then it will still only use the gas selected. And TTS will show for that gas OK? And if I switch to the next gas, will the TTS change?

Going to bed now.

Night all!

Andy Del · 9th May 2005, 04:29

Quote: (Originally Posted by Mdemon)

Thanks for your post, Andy. OK, have I got this straight? The VR3, in CCR mode, will assume all I am breathing is the dil I have selected, regardless of the other gasses I have switched on?

Short answer - no. Longer answer - No, what the computer is considering on the bottom is:

1. your breathing gas as far as the decompression obligation you are racking up
2. the setpoint you have set, or the PO2 of the connected cell.

On ascent, the computer has:

1. recorded your deco obligation,
2. is calculating your deco stops accordign to the gas you are breathing and the current PO2 setpoint.
3. is estimating your TTS by taking into account all available (turned on) gasses.

So your stop lengths and TTS will not be accurate. You'll need to wait until each stop clears, or follow the little man up the slope.

Very long answer - Delta-P have to put me on the payroll!

Quote:

Final question (prepared to be slagged for being thick, but it's late and I'm a bit slow...) - if I switch to OC then it will still only use the gas selected. And TTS will show for that gas OK? And if I switch to the next gas, will the TTS change? Going to bed now. Night all!

Not really, if you have the gasses you are going to use for deco activated (turned on) then the TTS will reflect the use of those gasses. If they re off, it will only estimate the TTS based on what is on. The gas switches don't effect the TTS, they effect your body. The settings on the computer will effect the deco prediction/TTS. (Hey, prediction is a pretty good word to use!) In short, the computer doesn't know the gasses which are turned off exist at all, and expected the ones switched on to be used during ascent, based on their MOD.

I hope that makes sense - it's afternoon here, and I need my nap.

Mdemon · 9th May 2005, 19:54

Thanks Andy.

DeltaP would get a lot less flack for their manuals if they DID put you on the payroll!

Andy Del · 10th May 2005, 20:57

Quote: (Originally Posted by Mdemon)

Thanks Andy.

DeltaP would get a lot less flack for their manuals if they DID put you on the payroll!

Just don't tell work, they're already suspicious of what I do in my free periods!

Mark Chase · 11th May 2005, 13:41

Quote: (Originally Posted by Andy Del)

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.

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, ..

??? I kind of understand what you're saying but its a bit contradictory. I used to have a Vytec. Now THAT only calculated deco on the gas you were breathing. As a result on 21/35 it would show me a TTS deco figure of 120mins. Then I switch to 32% at 40m and it shows me a new TTS figure of 80mins on 32% then I switch to 80% at 10m and it shows me another new TTS figure of 30mins.

Total deco would be something like 60mins..

The VR3 doesn’t do this at all. It calculates my deco TTS on ALL the gasses switched ON. On OC it gives me a TTS figure of 60mins based on bottom gas and two gas switches to 32% and 80%. I have to confirm the gas is switched by ticking it with a push of the right hand button but doing this does not alter my TTS in any way.

I haven’t done this on CCR but I am assuming it’s the same. If I had 32% and 80% marked as ON gases the VR3 will calculate my deco assuming a switch of diluents at 40m and at 10m. It will ask me to confirm that I have switched diluents at the correct depths but this will not alter the deco.

What will happen is if I forget to confirm the gas switch the TTS figure of 60mins will stay as 60mins but it will take much longer than that to clear as it will correctly assume I am on He for all deco.

So a dive to 60m for 60mins on 10/50 diluient should show 161mins TTS

However a Dive to 60m for 60min will show a TTS of 139mins if you tell the VR3 that your switching to 32% at 35m and 80% at 10m.

As a result despite the fact your VR3 shows 139mins to the surface you will be waiting for 161mins unless you confirm the gas switches.

Confusing bit is unless you switch off the 32% and 80% you will have no idea how long you will be in the water for.

Does this make sense?

ATB

Mark Chase

Nad · 11th May 2005, 14:33

Quote: (Originally Posted by Mark Chase)

The VR3 doesn’t do this at all. It calculates my deco TTS on ALL the gasses switched ON. On OC it gives me a TTS figure of 60mins based on bottom gas and two gas switches to 32% and 80%. I have to confirm the gas is switched by ticking it with a push of the right hand button but doing this does not alter my TTS in any way.

That's it. Exactly what the VR3 do.

Quote:

I haven’t done this on CCR but I am assuming it’s the same. If I had 32% and 80% marked as ON gases the VR3 will calculate my deco assuming a switch of diluents at 40m and at 10m. It will ask me to confirm that I have switched diluents at the correct depths but this will not alter the deco.

Same, the TTS is calculated in consideration of the ON Dil.

Nad

Mark Chase · 11th May 2005, 14:36

Where does the VR3 hide this deco on back gas info? it not on the screen

TTS is the only deco information I can see. If I go on to stop list the stops are all shown asuming you use ALL the switched on gasses.

If the VR3 is actualy calculating deco on back gas only how does it come up with the TTS

It either does both but dosent show the back gas only option or it automaticly calculates for all available gases.

I dont see anything else making sense.

But then I never said i was clever

ATB

Mark Chase

Padowan · 11th May 2005, 15:23

Quote: (Originally Posted by Mark Chase)

Where does the VR3 hide this deco on back gas info? it not on the screen

TTS is the only deco information I can see. If I go on to stop list the stops are all shown asuming you use ALL the switched on gasses.

If the VR3 is actualy calculating deco on back gas only how does it come up with the TTS

It either does both but dosent show the back gas only option or it automaticly calculates for all available gases.

You can't see the "deco on back gas" value as you call it, but what happens is that the TTS will be giving you for example a 20 minute stop at 6m depth assuming you switch to O2, if you leave the VR3 in (say) 50% as the breathing gas, the 20 minute stop will count down a lot slower, so each minute of the TTS may take 1:30 to clear - BUT the TTS will still assume that you are switching, so it'll take (say) 1:30 to drop from a 20min TTS to a displayed 19min TTS.

The same thing applies to running CCR, with the difference in the speed that each minute of TTS reduces by, being a function of the relative off-gas "efficiency" of the Diluent that you are breathing (have told it you are breathing) compared to the "efficiency" of the gasses it thinks you are switching to (ie the bailout gasses in CCR mode)

Make sence?

Andy Del · 11th May 2005, 20:48

Quote: (Originally Posted by Mark Chase)

The VR3 doesn’t do this at all. It calculates my deco TTS on ALL the gasses switched ON. On OC it gives me a TTS figure of 60mins based on bottom gas and two gas switches to 32% and 80%. I have to confirm the gas is switched by ticking it with a push of the right hand button but doing this does not alter my TTS in any way.

You're exactly right.

Quote:

I haven’t done this on CCR but I am assuming it’s the same. If I had 32% and 80% marked as ON gases the VR3 will calculate my deco assuming a switch of diluents at 40m and at 10m. It will ask me to confirm that I have switched diluents at the correct depths but this will not alter the deco.
Mark Chase

A-ha! On CCR, you don't (generally) switch diluents.

If you are going to use the bailout gasses, then you'd be pretty well bailing out OC, not using them as diluents. If this happens, my first action is to get onto the correct gas,. then worry about computers, etc. if necessary. I've also got a bailout table ready and waiting if there's no time to push buttons and watch the flashing lights...
A longer answer exists... but there's little point writing it up.

Mark Chase · 11th May 2005, 22:40

Quote: (Originally Posted by jptaylor9)

I agree with Andy Del's view... The VR3 computes your actual deco on the gas your breathing, no auto switching. It then takes the remaining gas loading in each tissue & calculates how long it'll take to complete deco based on all "ON" gases & there MODs'. This is shown as the TTS.

JT

John if your VR3 doesn’t automatically switch diluents at the MODs you set prior to the dive then how do you activate a diluent switch?

On my unit it’s automatic. At the predetermined MOD it switches diluent and shows me on the screen the diluent it has switched to. It has already allowed for the switch in the TTS calculation and I all I have to do is tick it with a single right button push to confirm I have made the switch to have the decompression profile continue to follow the TTS shown.

If I were to fail to confirm the switch the TTS data becomes garbage. I believe that if I go into gas list at that point and switch the new dileunt off, the computer will recompute my deco based on the remaining gases on the switched on list.

I have never tried this so it’s just going on the info in the manual. As we all know that’s a dodgy thing to do

ATB

Mark Chase

8th May 2005, 23:46	#11 (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: 1,931	Thanks for your post, Andy. Quote: (Originally Posted by Andy Del) 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.. OK, have I got this straight? The VR3, in CCR mode, will assume all I am breathing is the dil I have selected, regardless of the other gasses I have switched on? And if the answer is yes, then will the TTS be correct and show correct if I continue as CCR? Final question (prepared to be slagged for being thick, but it's late and I'm a bit slow...) - if I switch to OC then it will still only use the gas selected. And TTS will show for that gas OK? And if I switch to the next gas, will the TTS change? Going to bed now. Night all! __________________ 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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9th May 2005, 04:29	#12 (permalink)
Andy Del Classic KISSer Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: Australia, Sunny Sydney Posts: 421	Quote: (Originally Posted by Mdemon) Thanks for your post, Andy. OK, have I got this straight? The VR3, in CCR mode, will assume all I am breathing is the dil I have selected, regardless of the other gasses I have switched on? Short answer - no. Longer answer - No, what the computer is considering on the bottom is: 1. your breathing gas as far as the decompression obligation you are racking up 2. the setpoint you have set, or the PO2 of the connected cell. On ascent, the computer has: 1. recorded your deco obligation, 2. is calculating your deco stops accordign to the gas you are breathing and the current PO2 setpoint. 3. is estimating your TTS by taking into account all available (turned on) gasses. So your stop lengths and TTS will not be accurate. You'll need to wait until each stop clears, or follow the little man up the slope. Very long answer - Delta-P have to put me on the payroll! Quote: Final question (prepared to be slagged for being thick, but it's late and I'm a bit slow...) - if I switch to OC then it will still only use the gas selected. And TTS will show for that gas OK? And if I switch to the next gas, will the TTS change? Going to bed now. Night all! Not really, if you have the gasses you are going to use for deco activated (turned on) then the TTS will reflect the use of those gasses. If they re off, it will only estimate the TTS based on what is on. The gas switches don't effect the TTS, they effect your body. The settings on the computer will effect the deco prediction/TTS. (Hey, prediction is a pretty good word to use!) In short, the computer doesn't know the gasses which are turned off exist at all, and expected the ones switched on to be used during ascent, based on their MOD. I hope that makes sense - it's afternoon here, and I need my nap. __________________ Yellow - the colour of greatness!
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9th May 2005, 19:54	#13 (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: 1,931	Thanks Andy. DeltaP would get a lot less flack for their manuals if they DID put you on the payroll! __________________ 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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10th May 2005, 20:57	#14 (permalink)
Andy Del Classic KISSer Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: Australia, Sunny Sydney Posts: 421	Quote: (Originally Posted by Mdemon) Thanks Andy. DeltaP would get a lot less flack for their manuals if they DID put you on the payroll! Just don't tell work, they're already suspicious of what I do in my free periods! __________________ Yellow - the colour of greatness!
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11th May 2005, 13:41	#15 (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: 2,691	Quote: (Originally Posted by Andy Del) 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. 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, .. ??? I kind of understand what you're saying but its a bit contradictory. I used to have a Vytec. Now THAT only calculated deco on the gas you were breathing. As a result on 21/35 it would show me a TTS deco figure of 120mins. Then I switch to 32% at 40m and it shows me a new TTS figure of 80mins on 32% then I switch to 80% at 10m and it shows me another new TTS figure of 30mins. Total deco would be something like 60mins.. The VR3 doesn’t do this at all. It calculates my deco TTS on ALL the gasses switched ON. On OC it gives me a TTS figure of 60mins based on bottom gas and two gas switches to 32% and 80%. I have to confirm the gas is switched by ticking it with a push of the right hand button but doing this does not alter my TTS in any way. I haven’t done this on CCR but I am assuming it’s the same. If I had 32% and 80% marked as ON gases the VR3 will calculate my deco assuming a switch of diluents at 40m and at 10m. It will ask me to confirm that I have switched diluents at the correct depths but this will not alter the deco. What will happen is if I forget to confirm the gas switch the TTS figure of 60mins will stay as 60mins but it will take much longer than that to clear as it will correctly assume I am on He for all deco. So a dive to 60m for 60mins on 10/50 diluient should show 161mins TTS However a Dive to 60m for 60min will show a TTS of 139mins if you tell the VR3 that your switching to 32% at 35m and 80% at 10m. As a result despite the fact your VR3 shows 139mins to the surface you will be waiting for 161mins unless you confirm the gas switches. Confusing bit is unless you switch off the 32% and 80% you will have no idea how long you will be in the water for. Does this make sense? 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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11th May 2005, 14:33	#16 (permalink)
Nad Rebel to the Bone Current Rebreather/s: Ouroboros Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Other CCR Join Date: Mar 2005 Location: Europe Posts: 980	Quote: (Originally Posted by Mark Chase) The VR3 doesn’t do this at all. It calculates my deco TTS on ALL the gasses switched ON. On OC it gives me a TTS figure of 60mins based on bottom gas and two gas switches to 32% and 80%. I have to confirm the gas is switched by ticking it with a push of the right hand button but doing this does not alter my TTS in any way. That's it. Exactly what the VR3 do. Quote: I haven’t done this on CCR but I am assuming it’s the same. If I had 32% and 80% marked as ON gases the VR3 will calculate my deco assuming a switch of diluents at 40m and at 10m. It will ask me to confirm that I have switched diluents at the correct depths but this will not alter the deco. Same, the TTS is calculated in consideration of the ON Dil. Nad __________________ The Impossible is often the Untried
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11th May 2005, 14:36	#17 (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: 2,691	Where does the VR3 hide this deco on back gas info? it not on the screen TTS is the only deco information I can see. If I go on to stop list the stops are all shown asuming you use ALL the switched on gasses. If the VR3 is actualy calculating deco on back gas only how does it come up with the TTS It either does both but dosent show the back gas only option or it automaticly calculates for all available gases. I dont see anything else making sense. But then I never said i was clever 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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11th May 2005, 15:23	#18 (permalink)
Padowan Proper Boffin Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Kent, UK. Posts: 518	Quote: (Originally Posted by Mark Chase) Where does the VR3 hide this deco on back gas info? it not on the screen TTS is the only deco information I can see. If I go on to stop list the stops are all shown asuming you use ALL the switched on gasses. If the VR3 is actualy calculating deco on back gas only how does it come up with the TTS It either does both but dosent show the back gas only option or it automaticly calculates for all available gases. You can't see the "deco on back gas" value as you call it, but what happens is that the TTS will be giving you for example a 20 minute stop at 6m depth assuming you switch to O2, if you leave the VR3 in (say) 50% as the breathing gas, the 20 minute stop will count down a lot slower, so each minute of the TTS may take 1:30 to clear - BUT the TTS will still assume that you are switching, so it'll take (say) 1:30 to drop from a 20min TTS to a displayed 19min TTS. The same thing applies to running CCR, with the difference in the speed that each minute of TTS reduces by, being a function of the relative off-gas "efficiency" of the Diluent that you are breathing (have told it you are breathing) compared to the "efficiency" of the gasses it thinks you are switching to (ie the bailout gasses in CCR mode) Make sence? __________________ Padowan The future's bright, the future's Yellow .....for now padowan.net - Latest Video: Scapa Flow Rebreather Diving
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11th May 2005, 20:48	#19 (permalink)
Andy Del Classic KISSer Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: Australia, Sunny Sydney Posts: 421	Quote: (Originally Posted by Mark Chase) The VR3 doesn’t do this at all. It calculates my deco TTS on ALL the gasses switched ON. On OC it gives me a TTS figure of 60mins based on bottom gas and two gas switches to 32% and 80%. I have to confirm the gas is switched by ticking it with a push of the right hand button but doing this does not alter my TTS in any way. You're exactly right. Quote: I haven’t done this on CCR but I am assuming it’s the same. If I had 32% and 80% marked as ON gases the VR3 will calculate my deco assuming a switch of diluents at 40m and at 10m. It will ask me to confirm that I have switched diluents at the correct depths but this will not alter the deco. Mark Chase A-ha! On CCR, you don't (generally) switch diluents. If you are going to use the bailout gasses, then you'd be pretty well bailing out OC, not using them as diluents. If this happens, my first action is to get onto the correct gas,. then worry about computers, etc. if necessary. I've also got a bailout table ready and waiting if there's no time to push buttons and watch the flashing lights... A longer answer exists... but there's little point writing it up. __________________ Yellow - the colour of greatness!
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11th May 2005, 22:40	#20 (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: 2,691	Quote: (Originally Posted by jptaylor9) I agree with Andy Del's view... The VR3 computes your actual deco on the gas your breathing, no auto switching. It then takes the remaining gas loading in each tissue & calculates how long it'll take to complete deco based on all "ON" gases & there MODs'. This is shown as the TTS. JT John if your VR3 doesn’t automatically switch diluents at the MODs you set prior to the dive then how do you activate a diluent switch? On my unit it’s automatic. At the predetermined MOD it switches diluent and shows me on the screen the diluent it has switched to. It has already allowed for the switch in the TTS calculation and I all I have to do is tick it with a single right button push to confirm I have made the switch to have the decompression profile continue to follow the TTS shown. If I were to fail to confirm the switch the TTS data becomes garbage. I believe that if I go into gas list at that point and switch the new dileunt off, the computer will recompute my deco based on the remaining gases on the switched on list. I have never tried this so it’s just going on the info in the manual. As we all know that’s a dodgy thing to do 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
(Online)

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