Perdix Settings to Match Oceanic Geo / Veo

[MargaritaMike]

I am about to go diving with a new buddy. I asked her what computer she uses and she said a newer Oceanic wrist mode that is NOT AIl. I am considering setting one of my Perdix GF settings to match hers so I will see the same readings as she does. I'll set my Perdix on OC Tec. We will be doing rec diving in Cozumel. My previous buddy (my wife) quit diving, which is where I got the 2nd Perdix.
I know this has been discussed in multiple threads, but I can't find anywhere that says "these GF settings will give ('almost') the same profile as the Geo / Veo. This may not exist, but if someone knows, can you please let me know? Otherwise, I get to do a lot of experimentation (on paper).

Thanks for not calling me stupid.

Cheers -

 

[rongoodman]

Why not loan her one of the Shearwaters and choose whatever settings you like for both?

 

[Cyborg Pirate]

leave it in OC REC. but change it to low conservatism

if you change it to OC Tec it will not give you a safety stop, also the timer is not displayed other then a bar running under the minutes.

If you are not used to using the OC Tec mode don't use it.

 

[jgttrey]

Depends on which algorithm she selects on her oceanic, but unless she adds conservative factors, her computer will be way more aggressive than your Perdix with any reasonable GF.

I use one my kids Atom 3.1s for a watch on some trips along with my Perdix or Petrel, which usually at 30/70. I don't try to match them - watching differences just for fun. I'll be into deco on the Shearwater with many minutes of NDL left on the Oceanic. I follow the Shearwater.

 

[stuartv]

On the Shearwater, GF Lo will not be used unless you go into deco, so setting GF Hi is all that matters for trying to match an Oceanic (when doing NDL dives).

@scubadada has a lot of experience with this. But, I believe a GF Hi of 90 or 95 will come the closest to matching an Oceanic that is running the DSAT algorithm. If it's running PelagicZ (or whatever they call it), then I don't know what GF Hi would be close.

For matching DSAT, GF Hi whether 90 or 95 comes closest just depends on the dive profile. Personally, in your situation, I would probably go for GF Hi of 90 (vs 95).

Also, the more dives you do in a row (or on consecutive days), the more they (the Shearwater and they Oceanic) will start to diverge.

 

[scubadada]

Thanks @stuartv

I have dived a couple hundred dives with an Oceanic VT3 and a Dive Rite Nitek Q. My conclusion is that it is not possible to "match" DSAT with Buhlmann ZH-L16C with GF. Don't get me wrong, you can get close, you just can't really match. The two algorithms perform somewhat differently based on depth and repetitive dives, just to name 2 important variables. I dive my Nitek Q at a GF hi of between 90-100. I've learned a lot but it's become so annoying to always be adjusting my Nitek Q, that I have gone back to diving my Geo2 as backup, it matches my VT3 within 30 seconds. When my 8 year old VT3 finally dies, I will move on to Buhlmann and will use my Nitek Q for backup. I am currently quite covetous of a Teric, heck, I already have a couple of PPS transmitters.

If anyone has specific questions regarding my quest to match, send me a PM, I'd be glad to respond

 

[Marie13]

I have my backup Geo set to DSAT (as it always has been) and my Perdix is at medium. I’ve never bothered to compare them yet.

 

[scubadada]

I have my backup Geo set to DSAT (as it always has been) and my Perdix is at medium. I’ve never bothered to compare them yet.

Your Geo2 running DSAT will likely always be more liberal than your Shearwater at 40/85. This is probably not far off from PZ+

 

[MargaritaMike]

Thanks to everyone. This is some great information. I will make some adjustments and then see how it works. I may set the two Perdix a little different (one high - one medium). It won't hurt this old body to be a little more conservative. I just hope my broken back holds up.

Thanks again.
Cheers -

 

[outofofficebrb]

I have my backup Geo set to DSAT (as it always has been) and my Perdix is at medium. I’ve never bothered to compare them yet.

I have the same setup but with a Veo 2. I dive in medium conservativeness if I am remote and if I am in an easily accessible area, I go low.

Forgive me, @MargaritaMike, if this is a dense question but it is mostly out of curiosity. My buddy/partner is still diving a Suunto and I have moved on to the above setup. While our algorithms yield very different results, we communicate and have a mutual understanding at what point we communicate to the other diver that we have a certain amount of NDL left and what those signals are and what they mean. It is not necessary for us to match, though I understand why that would be convenient...

I sometimes will dip down a little deeper than him, etc., but I always try to keep above a 5 min NDL. We both tap our computers, signal 5, and signal to shallow up a bit. We can also tap on our computer in the same manner but point to the other person and that is a way to ask how much NDL time left and have that person signal back. I kind of like this arrangement as it prevents one or both of us from making assumptions and becoming complacement. I am not suggesting you will do this by having matching algorithms; I’m merely saying the extra “hassle” prevents this for me and I like that. Especially with a new dive partner.