Question Perdix Experts - Question for You...

[arkstorm]

When diving with back gas and a deco bottle (or two), under what circumstances would I want to use the Perdix (Perdix Ai/Perdix 2) in "3-Gas Nitrox" mode as opposed to "Open Circuit Tech" mode?

I realize the manual says 3-gas mode is for those beginning into tech diving, but why wouldn't you just use OC tech mode from the start?

I came to realize today that in 3-gas mode you can't change GF during a dive (which was an exercise we had planned during a training dive today).

Also noticed that in 3-gas mode the Perdix still gives you a safety stop after the deco obligation is cleared.

So what is 3-gas mode really there for?

 

[inquis]

Guessing... 3-nitrox may save you from having to skip over the helium numbers?

 

[arkstorm]

Guessing... 3-nitrox may save you from having to skip over the helium numbers?

I don’t see the benefit. It’s just as easy to set the He number to zero in OC Tech mode when defining the gasses.

Why have a whole additional quasi tech mode just to avoid that nominal step?

 

[inquis]

My opinion is they added that to compete with various other recreational-oriented computers. Functionally, no difference. On the advertising spiel, it is golden.

 

[arkstorm]

My opinion is they added that to compete with various other recreational-oriented computers. Functionally, no difference. On the advertising spiel, it is golden.

That is a possibility.

 

[GF99/99]

My opinion is they added that to compete with various other recreational-oriented computers. Functionally, no difference. On the advertising spiel, it is golden.

I think that is exactly what it is. A sales grab to novice diver.

Lets be honest since the Predator to Perdix not much has changed and even just a couple years ago the amount of people that knew what a Perdix/Shearwater computer was pretty small. So Shearwater needed to jump on the band wagon with all the other computer companies and come out with some kind of sales grab and get there name out there.

I think every since Shearwater got bought out there is a big push to up sales especially in the recreational market. And the only way to do that was to come up with sales gimmicks like "3 gas mode"

Can't wait to see what comes out at next years DEMA show. Maybe a "light tec mode" "medium tec mode" hardcore tec mode" and heck while were at it make a "4 gas mode" "5 gas mode" etc. etc.

 

[Belzelbub]

My opinion is they added that to compete with various other recreational-oriented computers. Functionally, no difference. On the advertising spiel, it is golden.

That was likely the reason for the rec mode originally. 3 gas Nx mode was originally called OC rec mode and most likely dates back to when the Perdix was first introduced, so it’s been around for a while. Perhaps even earlier.

When the Peregrine was introduced, which was definitely aimed at the rec market, OC rec was renamed to 3 gas Nx. That was because single gas modes for air and Nx were introduced.

I’m a recreational diver with a Perdix AI. I prefer the display of the rec modes, so that’s what I’ve used since I got it.

 

[arkstorm]

3 gas Nx mode was originally called OC rec mode and most likely dates back to when the Perdix was first introduced, so it’s been around for a while. Perhaps even earlier.

Are you saying that when the Perdix was first introduced there was no single gas "Air" mode or single gas "Nitrox" mode?

Why would any non-tech diver need a 3-gas mode since gas switching (for whatever purpose, e.g., accelerated deco) is strictly a tech diving practice?

There must be some reason for it other than just a marketing ploy, or am I giving Shearwater too much credit?

Perhaps someone from Shearwater can chime in here and explain when I might want to use 3-gas Nx mode over OC Tech mode when diving with multiple mixes?

 

[inquis]

Perhaps someone from Shearwater can chime in here

They are pretty responsive to emails: info@shearwater.com

 

[BoltSnap]

Why would any non-tech diver need a 3-gas mode since gas switching (for whatever purpose, e.g., accelerated deco) is strictly a tech diving practice?

There are probably more people doing switching gases without tech c-cards than the ones with tech c-cards around the world especially with one deco bottle.