Shearwater Perdix AI

[Joneill]

Can't you just calculate in your head your safety stop gas consumption? Then just add to the GTR.

Personally, I never depend on GTR as others have said before. I know I will get flamed for this comment.

Or you could just increase the reserve pressure you set to cover a safety stop as well?

 

[stuartv]

The problem with GTR is that most of us seem to agree that what GTR should be telling you is how long you have at the current depth until you have to start your ascent, in order to arrive at the surface with the configured reserve (in psi or bar) left. Assuming you only use the tank you are currently using, and assuming you ascend at 30 ft/min, and assuming you do all stops that the Perdix tells you to (including required and optional).

And that is not how GTR works (on the Perdix). Instead, it doesn't factor in the (optional) safety stop and it doesn't even display a GTR if you have a mandatory deco stop.

 

[Kevrumbo]

The problem with GTR is that most of us seem to agree that what GTR should be telling you is how long you have at the current depth until you have to start your ascent, in order to arrive at the surface with the configured reserve (in psi or bar) left. Assuming you only use the tank you are currently using, and assuming you ascend at 30 ft/min, and assuming you do all stops that the Perdix tells you to (including required and optional).

And that is not how GTR works (on the Perdix). Instead, it doesn't factor in the (optional) safety stop and it doesn't even display a GTR if you have a mandatory deco stop.

@stuartv -To have any future value added utility for you and your tech/wreck diving interests, the wireless AI/GTR feature has gotta have a lot more function capability than it does right now. Since Shearwater caters to the technical diving market as well, here are some suggested features to develop for the next product improvement cycle. . .

For Tech Open Circuit training & novice tech divers, some preferred practical GTR functionality & info examples for a user entered Minimim Gas Reserve/Rock Bottom pressure value:

• Based on this Minimum Gas Reserve, for overhead cave/wreck diving, the GTR utility would also calculate & display when prompted, a time remaining or countdown to Modified Third's (or Sixth's or "1/n") Turn Pressure. (Stage bottle Modified Third's support -i.e. Half plus 15 bar AL80 Stage cylinder(s)- would be useful, but requires more transmitters to monitor each stage cylinder used, or in lieu of additional transmitters, a user entered value for the number of stages used and each of their volume "tank factor" capacities.)
• A calculation & prompted display of time remaining or countdown to perform an emergency Lost Buddy Search based on one-half the above Modified Turn Pressure calculation.
• A tank switch reminder/indicator based on user entered delta pressure value for doubles sidemount diving.

IMO, these are useful & vital GTR features to have for open circuit Tech/Overhead Diving, and easy algorithms to develop and implement for the next generation wireless AI product model. I would still back it all up with SPG's however along with manually knowing all the critical pre-dive plan values of Minimum Gas Reserve, Modified Third's, sidemount tank switch pressures, and figuring out gas turn pressures on-the-fly as needed in a Lost Buddy Search. But then again knowing all these parameters as you should in back-up:

Why do you need an expensive complex digital wireless AI/GTR unit when you can economically use the more practical, more reliable, no batteries needed analog SPG manometer to start with in the first place?

 

[luscioman]

I always said that I would get a Shearwater if they had AI. I just ordered mine today and will hopefully test it out this weekend. I am very excited.

 

[Neilwood]

I will probably make my purchase of one in January once Xmas spending is over - my present to myself (as well as a nice new MTM drysuit).

That is assuming I can find a price for the Perdix AI as no UK stockists appear to have it listed yet.

 

[stuartv]

@stuartv -To have any future value added utility for you and your tech/wreck diving interests, the wireless AI/GTR feature has gotta have a lot more function capability than it does right now.
...

IMO, these are useful & vital GTR features to have for open circuit Tech/Overhead Diving

You don't seem to think these things would be useful to you. They certainly aren't vital to me. So, who exactly are you saying these things are vital to?

I just want wireless AI to work like it "should" when I am diving with a single gas supply. That would cover most of my diving and 100% of the diving that the vast majority of divers in the world actually do.

Why do you and a few others seem to constantly harp on AI and push this valuation of "if it can't do everything and the kitchen sink for my expeditionary cave dives, then it is worthless"? Fine. You don't have a use for it. Do you not "get" that the diving you're doing represents a TINY fraction of all the diving that happens every day around the world? You're a 1%-er. Why do you post stuff that carries the very strong implication that something is worthless to you and, therefore, it should be worthless to everyone else, and anyone who finds value in it is clearly an inferior diver who needs to get more training, be smarter, and/or work on their skills?

Wireless AI with 1 transmitter is perfectly adequate to meet all the needs of the vast majority of divers ... if it's implemented correctly, of course. Please stop telling us all that using an SPG and doing the math in your head is easy. Please stop implying that we are somehow lazy or not smart enough or not well trained because we don't choose to do things that way for our single gas diving. Some of us don't want to get bent, so we actually make a choice to not put ourselves in a position where we ever have to do math while possibly narced. Having a computer that tells me my GTR (with all the stipulations that go along with that) could definitely save me from doing math in my head in some situations (where I'm comparing against what I "know" without doing actual arithmetic) - or serve as a sanity check to compare my mental math against (when they agree, good, when they disagree by much, I better re-check my math).

 

[rhwestfall]

Nice post

 

[Lorenzoid]

. . .

I just want wireless AI to work like it "should" when I am diving with a single gas supply. That would cover most of my diving and 100% of the diving that the vast majority of divers in the world actually do. . . .

As far as I have seen in these comments, nobody has mentioned any negatives to what you propose Shearwater modify. My prediction is that they will modify it.

As far as the issue of making the Perdix AI a tec diver's dream, it appears to me that Shearwater has gradually shifted or broadened its target market. Their early computers (Predator, etc.) were aimed squarely at those you refer to as "the 1%-ers." Recreational divers started buying Petrels because there was a convincing argument that despite all the extra power, the core design features--intuitive user interface, wonderful display, user-replaceable battery--were just as beneficial to rec divers as a tec divers. I see the Perdix AI as now aimed squarely at the recreational market. I think it would open a can of worms to try to fully automate tec diving gas usage, as there's almost no end to what could in theory be done with it when you put a transmitter on every bottle, etc. It could get real complicated real fast.

 

[stuartv]

As far as I have seen in these comments, nobody has mentioned any negatives to what you propose Shearwater modify. My prediction is that they will modify it.

I hope so (since I'm planning to buy one)!

As far as the issue of making the Perdix AI a tec diver's dream, it appears to me that Shearwater has gradually shifted or broadened its target market. Their early computers (Predator, etc.) were aimed squarely at those you refer to as "the 1%-ers." Recreational divers started buying Petrels because there was a convincing argument that despite all the extra power, the core design features--intuitive user interface, wonderful display, user-replaceable battery--were just as beneficial to rec divers as a tec divers. I see the Perdix AI as now aimed squarely at the recreational market. I think it would open a can of worms to try to fully automate tec diving gas usage, as there's almost no end to what could in theory be done with it when you put a transmitter on every bottle, etc. It could get real complicated real fast.

I see it a little differently. I see the PAI as one of the very rare products that can be all things to all people. I.e. instead of the worst of both worlds, it's the best of both worlds (or has the potential to be, anyway). Nothing about AI makes a Perdix AI any less useful than a non-AI Perdix or Petrel for the tech crowd. And having trimix and multi-gas support with GF does not make it any less useful or "good" for the recreational crowd.

What I see is that there are 2 crowds and 2 different uses for AI. For the recreational crowd, AI is useful for providing tank pressure (in a more convenient place) and GTR to people whose dives are more ad hoc. AI is useful for the tech crowd for a different reason - it's useful for simply gathering data for post-dive analysis... and the convenience of seeing your tank pressure alongside your other dive data (clearly, a minor thing). Both communities of divers have different reasons (though with some overlap) for why they might want AI, but the technology to support them both is the same.

I see your comment as suggesting that SW has changed its focus - meaning, deemphasize one area in favor of another. I see what SW has done as broadening its focus, not changing it. There is no less "value" to their traditional market. There is simply more value overall, which is of even more interest to a new(er) market.

 

[Basking Ridge Diver]

I see it a little differently. I see the PAI as one of the very rare products that can be all things to all people. I.e. instead of the worst of both worlds, it's the best of both worlds (or has the potential to be, anyway). Nothing about AI makes a Perdix AI any less useful than a non-AI Perdix or Petrel for the tech crowd. And having trimix and multi-gas support with GF does not make it any less useful or "good" for the recreational crowd.

Yesterday I bit the bullet and purchased a Perdix with AI and transmitter. I bought the AI and transmitter not necessarily because I will use it or wanted it. I bought it because the hype of folks dumping theirs Petrels or Perdix and buying AI (not just on scubaboard but on most every board I could find) - on resale - I don't want to be one of those that is looking to sell without AI. Because the market for a great computer with AI seems to be bigger than the market for just a great computer...

Hopefully I won't have to find out - if I decide to sell.