VR3 BUH or VPM

tecdivertraining · 10th April 2008, 09:35

Quote: (Originally Posted by Drmike)

This is one of the reasons I dive with a couple of comps (3) I figure chances of all 3 going south are small - if they do its gonna be a loooong deco

PS you dont have time to have a McDECO you have too many students waiting! - how many certs you done this month?

Yes I'm Mcnackered at the moment I've just finished my 8th meg student plus 3 inspirations and a rather big bundle of OC classes to boot. I think over 20 certs in the last four weeks.

I am looking forward to some summer fun in mexico and then its back to Song Hong, fancy making me that BOB for the dives

.

Meng_Tze · 10th April 2008, 12:21

Quote: (Originally Posted by Mark Chase)

I did exactly this prety much all the time i owned VR3s I went to the first deep stop then added stops inbetween the jumps.

Isn't that strange? That a diver needs to add stops, change the ascend profile on a such a very expensive computer? You did it, I did it, many others do it....... what does that tell us about how this computer fits in the real world? I am sure they did good market research, planned for some conservatism and then implemented and messed things up.....

nobody · 10th April 2008, 13:35

I recal seeing some paper that the NEDU did on deco. It found that deeper stops increased the chance of DCS (11 out of 130 divers vs 1 in the other group or something like that). If that paper does exist and im not going crazy then wouldn't that suggest saving some money and not springing for VPM?

stuey · 10th April 2008, 16:11

Hi Lance,
interesting topic, as you know I was always ahead of you on the deco, FYI guys I'm also running a Vr3 buh with 4th cell alongside the vision, set at 15/85. I noticed that the Vr3 after my 2 deep stops wanted to then take me shallow quite quickly but the vision wouldn't let me go to these stops. I expect it would have if I wasn't using GF, and I could probably have used the diver on the line (Vr3) alongside the ceiling depth on the vision.
What I was doing was stopping every 3 mtrs for 1 min and by the time I got up to the Vr3 stop the vision would be OK at that depth. However on the 6m and 3m stops the TTS on the vision would be considerably more than the Vr3, but the vision at this point either counted down a fast minute or the Vr3 a slow minute, as the vision always cleared approx 8-10 mins before the Vr3. I don't consider the 8-10 mins a big deal. I think by comparing the times on both our buh Vr3's the difference would possibly have been that mine was on the 4th cell and yours was on a fixed setpoint. This was the first opportunity to undertake some lengthy deco and it was also interesting to watch how the Vr3 responded to changes in P02. By manually adding 02 to 1.3 and then watching the TTs suddenly drop 2-3 mins.
As a matter of interest has anyone out there made similar observations?

Ooo az zee zorb

**aainslie** · 10th April 2008, 16:34

Quote: (Originally Posted by Meng_Tze)

Isn't that strange? That a diver needs to add stops, change the ascend profile on a such a very expensive computer? You did it, I did it, many others do it....... what does that tell us about how this computer fits in the real world? I am sure they did good market research, planned for some conservatism and then implemented and messed things up.....

Freddy, you can't entirely blame them. When they initially set those up they were essentially implementing "Pyle Stops". Richard himself set these up based on intuition. THe bubble models THEN came along and gave slower initial ascent profiles - at which point it became obvious that while Pyle stops were a great idea, a smoothed slow ascent was even better.

My view of the VR3's so-called VPM implementation is that they've now tweaked the Buhlmann model to give a more gradual ascent. Which frankly sounds more like GF than VPM to me, but I'm sure they figured they could charge more for it by pretending it's VPM.

Oh - and Mike, going waaay back to your earlier point, I suddeenly realized why you think VPM looks more and more like Buhlmann - it's because in your VR3 implementation, it IS a tweaked Buhlmann. Hardly surprising as a result. Try running it side by side with an X1 and I think you'll see big differences, especially on a non-square profile.

Meng_Tze · 10th April 2008, 17:14

Quote: (Originally Posted by aainslie)

Freddy, you can't entirely blame them. When they initially set those up they were essentially implementing "Pyle Stops". Richard himself set these up based on intuition. THe bubble models THEN came along and gave slower initial ascent profiles - at which point it became obvious that while Pyle stops were a great idea, a smoothed slow ascent was even better.

Even with the added knowledge and data from the field, nothing (that I am aware of) was done to update this...? They may have been initially led by Dr. Pyle's intuition, the shape of the ascend, deep stop calculations etc. became matter of public domain and common knowledge....not updating this as a manufacturer constitutes 'messing up an implementation' in my book. If I would miss that boat, I would fire myself!

Quote:

Oh - and Mike, going waaay back to your earlier point, I suddeenly realized why you think VPM looks more and more like Buhlmann - it's because in your VR3 implementation, it IS a tweaked Buhlmann. Hardly surprising as a result. Try running it side by side with an X1 and I think you'll see big differences, especially on a non-square profile.

I saw that. For a little while I ran my VR3 as a backup to the X1 (I predominantly dive caves) and saw dramatic differences between VR3VPM and Vplanner. Dr Jekyll and Mr Hyde at play

Serge · 10th April 2008, 22:57

Quote: (Originally Posted by nobody)

I recal seeing some paper that the NEDU did on deco. It found that deeper stops increased the chance of DCS (11 out of 130 divers vs 1 in the other group or something like that). If that paper does exist and im not going crazy then wouldn't that suggest saving some money and not springing for VPM?

Or, did you mean just the opposite? VPM does not do "deep stops" as does the Buh (VR3).

Serge · 10th April 2008, 22:58

Quote: (Originally Posted by Meng_Tze)

... For a little while I ran my VR3 as a backup to the X1 (I predominantly dive caves) and saw dramatic differences between VR3VPM and Vplanner. Dr Jekyll and Mr Hyde at play

Would you mind posting some data for comparison?

Meng_Tze · 10th April 2008, 23:04

Quote: (Originally Posted by Serge)

Would you mind posting some data for comparison?

I cant really, never had any download facilities for the VR3, but when something 'major' happened, I logged it in my log book. I will check and see if I can find something. I do remember that the VR3 was always behind, or depending on your perspective, the X1 was alway in front.

Serge · 10th April 2008, 23:09

Quote: (Originally Posted by Meng_Tze)

I cant really, never had any download facilities for the VR3, but when something 'major' happened, I logged it in my log book. I will check and see if I can find something. I do remember that the VR3 was always behind, or depending on your perspective, the X1 was alway in front.

Thanks. Also please post what conservatism settings you had those on. According to my calcs, v-planner +5 gave me the same values as the VR3 on the most aggressive setting (Safe 0). Otherwise they are spot on.

10th April 2008, 09:35	#51 (permalink)
tecdivertraining RebreatherWorld Sponsor Current Rebreather/s: Inspiration Classic Inspiration Vision Evolution Megalodon Ouroboros Dolphin Other Rebreather/s: Not Bought Yet Dolphin Join Date: May 2005 Location: Phuket, Thailand Posts: 462	Re: VR3 BUH or VPM Quote: (Originally Posted by Drmike) This is one of the reasons I dive with a couple of comps (3) I figure chances of all 3 going south are small - if they do its gonna be a loooong deco PS you dont have time to have a McDECO you have too many students waiting! - how many certs you done this month? Yes I'm Mcnackered at the moment I've just finished my 8th meg student plus 3 inspirations and a rather big bundle of OC classes to boot. I think over 20 certs in the last four weeks. I am looking forward to some summer fun in mexico and then its back to Song Hong, fancy making me that BOB for the dives. __________________ Mathew Partridge Technical Director Pro-Tech Dive College www.protechdivers.com www.tech-ccr.com
(Offline)

10th April 2008, 12:21	#52 (permalink)
Meng_Tze 246 Bubbleless Cove Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2007 Location: FL, USA Posts: 111	Re: VR3 BUH or VPM Quote: (Originally Posted by Mark Chase) I did exactly this prety much all the time i owned VR3s I went to the first deep stop then added stops inbetween the jumps. Isn't that strange? That a diver needs to add stops, change the ascend profile on a such a very expensive computer? You did it, I did it, many others do it....... what does that tell us about how this computer fits in the real world? I am sure they did good market research, planned for some conservatism and then implemented and messed things up..... __________________ Homo Bonae Voluntatis
(Offline)

10th April 2008, 13:35	#53 (permalink)
nobody New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Aug 2007 Posts: 8	Re: VR3 BUH or VPM I recal seeing some paper that the NEDU did on deco. It found that deeper stops increased the chance of DCS (11 out of 130 divers vs 1 in the other group or something like that). If that paper does exist and im not going crazy then wouldn't that suggest saving some money and not springing for VPM?
(Offline)

10th April 2008, 16:11	#54 (permalink)
stuey New Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Aug 2006 Location: Thailand Posts: 49	Re: VR3 BUH or VPM Hi Lance, interesting topic, as you know I was always ahead of you on the deco, FYI guys I'm also running a Vr3 buh with 4th cell alongside the vision, set at 15/85. I noticed that the Vr3 after my 2 deep stops wanted to then take me shallow quite quickly but the vision wouldn't let me go to these stops. I expect it would have if I wasn't using GF, and I could probably have used the diver on the line (Vr3) alongside the ceiling depth on the vision. What I was doing was stopping every 3 mtrs for 1 min and by the time I got up to the Vr3 stop the vision would be OK at that depth. However on the 6m and 3m stops the TTS on the vision would be considerably more than the Vr3, but the vision at this point either counted down a fast minute or the Vr3 a slow minute, as the vision always cleared approx 8-10 mins before the Vr3. I don't consider the 8-10 mins a big deal. I think by comparing the times on both our buh Vr3's the difference would possibly have been that mine was on the 4th cell and yours was on a fixed setpoint. This was the first opportunity to undertake some lengthy deco and it was also interesting to watch how the Vr3 responded to changes in P02. By manually adding 02 to 1.3 and then watching the TTs suddenly drop 2-3 mins. As a matter of interest has anyone out there made similar observations? Ooo az zee zorb
(Offline)

10th April 2008, 16:34	#55 (permalink)
aainslie So Cal Tech Diver Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Apr 2006 Location: LA Posts: 196	Re: VR3 BUH or VPM Quote: (Originally Posted by Meng_Tze) Isn't that strange? That a diver needs to add stops, change the ascend profile on a such a very expensive computer? You did it, I did it, many others do it....... what does that tell us about how this computer fits in the real world? I am sure they did good market research, planned for some conservatism and then implemented and messed things up..... Freddy, you can't entirely blame them. When they initially set those up they were essentially implementing "Pyle Stops". Richard himself set these up based on intuition. THe bubble models THEN came along and gave slower initial ascent profiles - at which point it became obvious that while Pyle stops were a great idea, a smoothed slow ascent was even better. My view of the VR3's so-called VPM implementation is that they've now tweaked the Buhlmann model to give a more gradual ascent. Which frankly sounds more like GF than VPM to me, but I'm sure they figured they could charge more for it by pretending it's VPM. Oh - and Mike, going waaay back to your earlier point, I suddeenly realized why you think VPM looks more and more like Buhlmann - it's because in your VR3 implementation, it IS a tweaked Buhlmann. Hardly surprising as a result. Try running it side by side with an X1 and I think you'll see big differences, especially on a non-square profile. __________________ Andrew Ainslie
(Online)

10th April 2008, 17:14	#56 (permalink)
Meng_Tze 246 Bubbleless Cove Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2007 Location: FL, USA Posts: 111	Re: VR3 BUH or VPM Quote: (Originally Posted by aainslie) Freddy, you can't entirely blame them. When they initially set those up they were essentially implementing "Pyle Stops". Richard himself set these up based on intuition. THe bubble models THEN came along and gave slower initial ascent profiles - at which point it became obvious that while Pyle stops were a great idea, a smoothed slow ascent was even better. Even with the added knowledge and data from the field, nothing (that I am aware of) was done to update this...? They may have been initially led by Dr. Pyle's intuition, the shape of the ascend, deep stop calculations etc. became matter of public domain and common knowledge....not updating this as a manufacturer constitutes 'messing up an implementation' in my book. If I would miss that boat, I would fire myself! Quote: Oh - and Mike, going waaay back to your earlier point, I suddeenly realized why you think VPM looks more and more like Buhlmann - it's because in your VR3 implementation, it IS a tweaked Buhlmann. Hardly surprising as a result. Try running it side by side with an X1 and I think you'll see big differences, especially on a non-square profile. I saw that. For a little while I ran my VR3 as a backup to the X1 (I predominantly dive caves) and saw dramatic differences between VR3VPM and Vplanner. Dr Jekyll and Mr Hyde at play __________________ Homo Bonae Voluntatis
(Offline)

10th April 2008, 22:57	#57 (permalink)
Serge New Member Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Dec 2007 Location: NY Posts: 93	Re: VR3 BUH or VPM Quote: (Originally Posted by nobody) I recal seeing some paper that the NEDU did on deco. It found that deeper stops increased the chance of DCS (11 out of 130 divers vs 1 in the other group or something like that). If that paper does exist and im not going crazy then wouldn't that suggest saving some money and not springing for VPM? Or, did you mean just the opposite? VPM does not do "deep stops" as does the Buh (VR3).
(Offline)

10th April 2008, 22:58	#58 (permalink)
Serge New Member Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Dec 2007 Location: NY Posts: 93	Re: VR3 BUH or VPM Quote: (Originally Posted by Meng_Tze) ... For a little while I ran my VR3 as a backup to the X1 (I predominantly dive caves) and saw dramatic differences between VR3VPM and Vplanner. Dr Jekyll and Mr Hyde at play Would you mind posting some data for comparison?
(Offline)

10th April 2008, 23:04	#59 (permalink)
Meng_Tze 246 Bubbleless Cove Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2007 Location: FL, USA Posts: 111	Re: VR3 BUH or VPM Quote: (Originally Posted by Serge) Would you mind posting some data for comparison? I cant really, never had any download facilities for the VR3, but when something 'major' happened, I logged it in my log book. I will check and see if I can find something. I do remember that the VR3 was always behind, or depending on your perspective, the X1 was alway in front. __________________ Homo Bonae Voluntatis
(Offline)

10th April 2008, 23:09	#60 (permalink)
Serge New Member Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Dec 2007 Location: NY Posts: 93	Re: VR3 BUH or VPM Quote: (Originally Posted by Meng_Tze) I cant really, never had any download facilities for the VR3, but when something 'major' happened, I logged it in my log book. I will check and see if I can find something. I do remember that the VR3 was always behind, or depending on your perspective, the X1 was alway in front. Thanks. Also please post what conservatism settings you had those on. According to my calcs, v-planner +5 gave me the same values as the VR3 on the most aggressive setting (Safe 0). Otherwise they are spot on.
(Offline)

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