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A VS Cash Cow
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Discussion Starter · #1 ·
I was messing bout with my VR3 last night in simulate mode, just to check over some numbers and see what it might say for some upcoming dives. I don't much like a computer to do anything unexpected.

so i simulated a dive to 40m for 30mins running a PPO2 of 1.2, with around 22min time to surface, i then simulated a bailout to 32% at maximum bottom time and began the ascent, the time to surface of course changed to about 45mins which was what i expected. It may of been late and i was probably tired but as i ascended it gave me the various deepstops to do, which i found that if i did the deepstops on my bailout it would increase the deco obligation so from 45 minutes it began to increase the deco but if you went through the deepstops and went to get as shallow as possible to conserve your bailout gas, the VR3 put its virtual hands up and say 'go to tables' but still keeps monitoring your deco anyway.

so is the VR3 to be 'trusted' when you bailout from CCR?

if you miss the deepstops and get shallow quick can you use the VR3 still.

Is the 'go to tables' message a get out for the VR3?

edit - lets not argue over the term trusted please,it was the best word i could come up with.
 

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Mad as a Haddock
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AFAIK, if you miss stops, it does it's best to get you out rather than dropping into SOS mode. Never tried it, but obviously interesed.
 

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A VS Cash Cow
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Discussion Starter · #3 ·
it just occured to me as an odd function to have if the computer will not function correctly in that mode and your not able to be confident in what its saying.
 

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Trying to get the sim to match an actual dive is very tough, so I am not convinced that the results of teh sim will be reflected in teh dive, but it can give you an idea and certainly the TTS at the point of bailout should be correct.

Juz
 

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I was messing bout with my VR3 last night in simulate mode, just to check over some numbers and see what it might say for some upcoming dives. I don't much like a computer to do anything unexpected.

so i simulated a dive to 40m for 30mins running a PPO2 of 1.2, with around 22min time to surface, i then simulated a bailout to 32% at maximum bottom time and began the ascent, the time to surface of course changed to about 45mins which was what i expected. It may of been late and i was probably tired but as i ascended it gave me the various deepstops to do, which i found that if i did the deepstops on my bailout it would increase the deco obligation so from 45 minutes it began to increase the deco but if you went through the deepstops and went to get as shallow as possible to conserve your bailout gas, the VR3 put its virtual hands up and say 'go to tables' but still keeps monitoring your deco anyway.

so is the VR3 to be 'trusted' when you bailout from CCR?

if you miss the deepstops and get shallow quick can you use the VR3 still.

Is the 'go to tables' message a get out for the VR3?

edit - lets not argue over the term trusted please,it was the best word i could come up with.
Your description does not make sense.

When you change from CC to OC the VR3 gives you the deco plan using the gases that are configured as "ON".

If it gave you 45minutes and you followed the plan then it would be 45 minutes to surface.

If you go ascend more slowly than the VR3 is expecting your TTS will increase, if you go above the deco "ceiling" for more than 1 minute it will display "refer to tables". You are effectively on your own you have blown a compartment and have to make up your own mind as to what the best course of action would be.

In reality if you redescend and redo stops that it considers you have missed then the plan it gives you is probably quite usful info.

For 24hours afterwards the VR3 will show "Missed Stops" but still gives appropriate deco for subsequent dives.

I am stuggling to understand what you think the VR3 should say when you have missed stops that it wanted you to do.

Do you think that the VR3 should show you the phone number for the nearest chamber instead of "refer to tables"? would this be more useful to you? :angel:



What do you mean by a "get out"? would it be something like - "if you dont follow the advice of the computer you are on your own."

Do you know of a better way of communicating with the user that they have blown it according to the algo that they have chosen?
 

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A VS Cash Cow
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Discussion Starter · #6 ·
Do you think that the VR3 should show you the phone number for the nearest chamber instead of "refer to tables"? would this be more useful to you? :angel:
Gibbon i'll run it again tonight but from what i saw (it was late) it gave 45min TTS at the start of ascent and then when i simulated stopping at the deepstops instead of ticking off deco it increased the TTS. I was following the ascent rate as i was only simulating the dive to get an idea of what the computer could show me.


if it all really goes wrong i'd like my VR3 to show me a picture of some cute kittens or something. :)
 

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Gibbon i'll run it again tonight but from what i saw (it was late) it gave 45min TTS at the start of ascent and then when i simulated stopping at the deepstops instead of ticking off deco it increased the TTS. I was following the ascent rate as i was only simulating the dive to get an idea of what the computer could show me.


if it all really goes wrong i'd like my VR3 to show me a picture of some cute kittens or something. :)
best get a colour one then :angel:

Following Juz's post, I don't know much about the simulator mode but have had my VR3 showing "refer to tables" and "missed deco" a number of times mostly when following VPM tables.
 

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Is fully Mod 1'd up
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Its going to continue to add deco because at the deepstop depth on OC your still on gassing some tissue compartments right ?? From what I've been reading recently about deco that seems to be the case. If you go straight to 6m to do deco then your on a really aggressive deco profile...Hence the computer saying 'get out of this yourself pal'

I'm most probably wrong with all this but I think thats basically whats happening...

Cheers

Adam
 

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Nefarious Activist
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Ok, I dive boris taking my deco from the onboard primary display, I also run an offboard VR3 with a fixed setpoint .05 below that set on the primary. I often end up with a minute or two's difference in the deco and as I am following the onboard unit which is tracking the actual PO2 I sometimes "bend" the VR3 and get the "use tables" instruction. In my experience, admittedly limited, I find that the offboard still gives me deco information that is within a few minutes of that given on the primary so from my perspective I am happy to finish the dive on the offboard VR3's info in the event of a loss of my primary display (PO2 information still available on secondary & HUD)

Ian
 
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Gibbon i'll run it again tonight but from what i saw (it was late) it gave 45min TTS at the start of ascent and then when i simulated stopping at the deepstops instead of ticking off deco it increased the TTS.
I think this is quite normal. The computer is running a conventional tissue model to which has been added a rule to do deep stops. The computer tells you to stop because we know deep stops are a "good thing", not because the tissue model requires it. As far as the model is concerned, you are still ongassing, so up goes the TTS. In a normal dive, it may be able to anticipate the effect of the deep stops and allow for them in the TTS displayed before you get there but once you do something drastic like swithcing to open circuit I imagine it goes back to basics and shows what the base model predicts. Am I right in thinking we are not talking about the VPM option here?

At the other end, if you go past your decompression ceiling, the computer knows there's a rule that you shouldn't do that (ho-hum, he's bent) but as far as the tissue model is concerned, you just start offgassing faster. If you descend back below the ceiling, the model will now give a shorter TTS than if you had done what you were supposed to do. Sadly, your body is not as simple as a Haldanean tissue model, so following the new schedule may not be as safe as following the original one. The VR3 is a grown-up's computer: it will not shut down on you when you get into trouble - it will keep running the model. The "use tables" thing is just there to warn you that it is running a model who's rules you have violated, so its up to you how you interpret what it says. I am making an assumption here that the VR3 doesn't do something cleverer that that but I would be very surprised if it does.

Tony
 

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if you miss the deepstops and get shallow quick can you use the VR3 still.
Yes. I regularly ascend thru the VR3 deep stops, I'm using the Vision deco as my main deco computer. The deco in "Use Tables" is still valid, it's closer to straight Buhlmann. The VR3 normally requires a few extra minutes over the Vision, that's with VR3 on 0% conservitism.

My VR3 always says DECOM MiSSED when i'm back on the boat :)

JT
 

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it just occured to me as an odd function to have if the computer will not function correctly in that mode and your not able to be confident in what its saying.
Well not really, what the VR is saying is "I calculated your deco to include deep stops, you ignored those deep stops therefore I can't be sure that my calculations are correct".

It a bloody sight better than an error message, but the machine is saying my initial calculations are no longer valid so I'm giving you my best guess!

Best do the deep stops. :teeth:
 

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The deep stops aren't real Buhlmann stops, there just padding, in an emergency (i.e. bailout) I'd be happy to blow them & pad shallow stops with any bailout gas left over once VR3 buhlmann stops cleared. Anoyingly, you loose the "man on a rope" in this mode....

If your VR3 is your primary deco computer, of course, do them on normal ascents.

JT

Note: Have bailed from a 60m dive on Inspo Classic, used VR3 for deco on both CCR & OC phases.
 
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