Multigas Computer is backup plan?

[Jason Ooi]

Hi Joel, In HK hard to find great multigas computers, we only can see VR3, Nitek He and Sunto, No Conchran, HS explorer dealer in HK market.
I heard that Cochran EMC-20 very compact, user -friendly stuff the only thing is CCR can't switch to OC bailout, therefore I chose Delta P VR3 C4 the only multigas computer for CC switched to OC, nevertheless I believe both are very good computers.

 

[Jason Ooi]

Joel, I just want to learn more from any professional tech divers, It seemed you voted multigas computer + dive table, How your backup plan can u share with me, did you bring both same computers?

Thanks

 

[karstdvr]

The Nitek HE is a nice unit. But it has limitations, first being the tiny hard to read screen, the second being the extremely unforgiving algorithm. The shallow stops can be WAY too long and you are penalized heavily for deeper stops or slower ascents. But like all tools once you know how to use them you get used to limitations that sometimes become comfort zones.

I remember when switching from classic Hamilton (haldanean) models to the bubble model. The decompression was cut by almost 30% that caused me some angst at first, now it's just a shape of decompression I have grown to enjoy.

Sounds like your buddy needed some better clips on his stages !

Cheers
JDS

The small screen of the HE doesn't bother me,as much as the weak back light,but I haven't found the algorithm to be unforgiving,in fact it has gotten me out ahead of the VR3s in some cases. I do like the ease of gas switch especially when I have a lot of tasks going on I don't have to dwell on that too long. You make a valid comment about used something will give you that warm and fuzzy.

Maybe a good product for you to R&D is the "tractor beam" for run away stage bottles...

 

[Jason Ooi]

VR3 VPM vs Cochran EMC20H..by Cerdic Verdier
Just click in the link http://www.cedricverdier.com/CochranVR3.pdf

 

[karstdvr]

Joel, I just want to learn more from any professional tech divers, It seemed you voted multigas computer + dive table, How your backup plan can u share with me, did you bring both same computers?

Thanks

Jason I thinking voting on your poll will be seriously skewed since it first appeared on the DIR board.

 

[Jason Ooi]

Jason I thinking voting on your poll will be seriously skewed since it first appeared on the DIR board.

Sorry about that, should be in technical specialty thread

 

[karstdvr]

VR3 VPM vs Cochran EMC20H..by Cerdic Verdier
Just click in the link http://www.cedricverdier.com/CochranVR3.pdf

Interesting review,but perhaps a little too superficial. To give a better side by side comparison I'd like to see it tested in several different depth/duration situations. Although the algorithms should be predictible,the conservatism built in by the manufacturer can't be predicted to generate a side by side curve,that is what I'd love to see a several test dive comparison.

 

[Jason Ooi]

Multigas computers comparison
Cochran EMC family comparison http://www.divecochran.com/computers/EMC-20H/comparisons.html
VR3 vs HS explorer and Nitek HE http://www.vr3.co.uk/vr3/main.php?content=comparison

 

[roakey]

Multigas computers comparison
VR3 vs HS explorer and Nitek HE http://www.vr3.co.uk/vr3/main.php?content=comparison

The VR3 is a clear winner because it has games (last row)

Roak

 

[*Floater*]

VR3 vs HS explorer and Nitek HE http://www.vr3.co.uk/vr3/main.php?content=comparison

What exactly do "Adjustable Shallow Stop Depth" and "Dynamic Decompression Ceiling" mean as computer features? Unlike the VR3, the HS Explorer doesn't have those features even though they sound like something one might want to have?

I'm just a novice tech diver. All my dives tech have been around 40-60m for bottom times of 20-40 minutes, mostly on air and EAN50 for deco, though I did try 21/35 and some of the weak nitrox mixes for bottom gas (EAN26 for 45m type of thing), but it just wasn't worth it. I use GAP-RGBM now and for deco, but I start the stops a little deeper and add time at the oxygen window. I write the deco schedule on my wriist stale, and I write the min to add for +5m of depth and +5min of time. That's my contingency.

For backup, I've ran GAP-RGBM profiles for from 30m to 70m at 3m intervals and from 10 min to 60 min at 5 min intervals. I then recorded the total required deco into a table in my wetnotes (for air and EAN50) and that's my backup. The shape of the curve for my dives is pretty much always the same. Short deep stops (around 1 min) starting at 80% ATA until I reach 21m, ~4-5 minutes spent there for oxygen window, then 2min per each 3m up until I'm at 15m or 12m, and from there to surface I spread the deco time in my tables in a roughly exponential curve.

This works okay as a backup for the types of dives I do and I use a weighted average depth so I don't get penalized too bad for deviating from square profiles. It wouldn't work at the edges of my tables (say 60min at 60m), but I don't really do those types of dives yet and I do adjust it a bit based on what makes sense. This backup also works on the surface or on the boat if for some reason the plan changes and I have to come up with a new schedule but don't have my (pocket) PC on me or the batteries died or something.

I wouldn't mind having an HS Explorer, since it also uses RGBM, but they are expensive and I don't really feel like I need one. So far I've never needed to go to a backup plan anyway.