Shearwater Perdix Air Integrated...Opinions

[beester]

Your whole post simply confirms it is not simple doing it that way. The correct answer is litres per minute, not bar per minute. Litres per minute works no matter the size of your tank, you are then comparing apples to apples. If you do it your way, you need to know the size of the tank and the multiplier effect needed to compare to someone else. Too hard.

Like Kev says, your manometer reads in BAR (or PSI) so why make it more difficult by calculating SAC in liters, which forces you to recalculate underwater. Most of us dive only a limited set of tank volumes, so if you've made the calculation once, and just note down the BAR per minute (or 5 minutes) at 1 ATA for those sets of tanks you are good to go.

I calculate per 5 min segment because that's when I normally check my status (every 5 minutes). My range of diving tanks is S80 (11,2L), 15L mono, Double 8,5L, Double 12L or Double 18L.

I know by heart my Bar consumption at surface for these tanks: 8 (S80 11,2L mono), 7 (15L mono), 6 (D8,5l), 4 (D12L), 2.5 (D18L). This is average, not exact, but good enough.

So diving my double 12 at 40m I know I'll use 20 bar per 5 minutes, I was at 180bar 5 minutes ago, I expect to be at 160, quick check, yes 160 all ok. Or 155, mmm my sac is quite high, what could be the reason (taskloading, cold, a lot of current)... adjust my plan.

It seems like a lot of mental taskloading, and maybe in the beginning it is, but you get accustomed to it, and it forces additional awareness.

 

[AJ]

Not everyone wants (or is able to) maintain that mental burden while enjoying a dive. I'm into post-analysis.

If you like post analysis as an integral part of the dive then there's no other option than AI. Totally agree on this.

Please consider this: Is is possible (for some people) that the more they offload the nuts and bolts of getting home safely, the more they can enjoy their dive?

No problem, if you just want to go diving without the mental burden, go ahead. Enjoy your dive, but please do not to attempt to do more demanding dives like deep (even 40m/120ft, let alone beyond that) or cave this way. That's what this is all about. Relying on a computer (does not matter AI or SPG) in these circumstances to stay save will get you in trouble sooner or later. That's why tech divers do things different than rec divers (plan your dive, dive your plan). Not better, just different.

 

[DevonDiver]

In principle, I don't have a problem with AI for tech. However....

I don't think that the transmitter technology is quite 'at that level' yet. They're relatively fragile and don't route well from many 1st stages. You can put them on short HP hoses, but that adds O-rings.

For sidemount, I don't think that having 'butt-plug' sized protrusions in your armpits is a recipe for comfort or avoiding snarling with other kit..

When transmitters are refined down to the size of button gauges.. and the connection is sufficiently reliable that I wouldn't be tempted to backup with analogue SPGs.... then it's something that'd have merit (for me).

Until then, at a tech level, they don't provide any tangible benefits in safety or functionality (that aren't already provided by good drills and skills) ... But there's still some drawbacks.... So nope, not for me yet.

 

[Macan]

In principle, I don't have a problem with AI for tech. However....

I don't think that the transmitter technology is quite 'at that level' yet. They're relatively fragile and don't route well from many 1st stages. You can put them on short HP hoses, but that adds O-rings.

For sidemount, I don't think that having 'butt-plug' sized protrusions in your armpits is a recipe for comfort or avoiding snarling with other kit..

When transmitters are refined down to the size of button gauges.. and the connection is sufficiently reliable that I wouldn't be tempted to backup with analogue SPGs.... then it's something that'd have merit (for me).

Until then, at a tech level, they don't provide any tangible benefits in safety or functionality (that aren't already provided by good drills and skills) ... But there's still some drawbacks.... So nope, not for me yet.

The Transmitter (at least the Suunto that I use) is actually very robust and routes well on Apeks regs. Never leaked. No need for short HP hoses. I've been using the Suunto D9 Transmitter on doubles for the past 11 years since they first came out. I assume newer transmitters are smaller and better than my old Suunto.

If ever you have to shutdown your left post on doubles, your analog SPG is gone but the WAI Transmitter (on the right post) will continue to give you gas pressure reading for both tanks. Had this happened once. Additionally, the ease of just flicking your right wrist to check remaining gas in challenging situations is among the many benefits of AI in Rec or Tec.

 

[DevonDiver]

Duplicate

 

[DevonDiver]

The Transmitter (at least the Suunto that I use) is actually very robust and routes well on Apeks regs. Never leaked. No need for short HP hoses

I guess this kinda depends on the diving (and abuse) that your kit suffers. For me, they're nowhere near robust enough. Hence, why I stated that in my opinion.

HP short hoses are needed on some cylinders and/or some 1st stages.. and many sidemount configurations...if you wish to route down the tank. As opposed to garishly protruding above the diver.

The reason is because some cylinder necks are too stumpy to allow the transmitter to fit.

Maybe your cylinders aren't. Or maybe you're happy with a butt-plug antenna vibe.. But that's certainly not universal.

But as I said, that's just my opinions, in the tech diving context. I'm not telling anyone else what to do... or attempting to promote any sort of 'facts'.

 

[Lorenzoid]

Using your analogy (for tech divers, not talking for recreational): It's like having parking sensors but only fitted to the front of your car, but not on the back/sides. No use having the sensor if I still need old Mark I Eyeball to measure distances to side and back before parking. . . .

But I still need to make the calculation and then visual check on manometer for my bottom stage and deco stages. That's me having to look over the back and sides of the car, because there are no parking sensors.

Have you seen the posts from the super-data-nerds proposing sensors on stage and deco tanks, automatically sensing which tank is being breathed from, etc.? It's all technologically possible. But it sure would seem to widen the room for error.

 

[Kevrumbo]

. . .
It seems like a lot of mental taskloading, and maybe in the beginning it is, but you get accustomed to it, and it forces additional awareness.

It only seems like a "mental burden" as @lowviz and others claim because just like learning anything new & unfamiliar, it takes time to read, comprehend and accommodate the process versus actually practicing it. And it takes a lot of time and effort to explain it all as well -for example you can write a whole page on how to sum a computer spreadsheet column for someone who is unfamiliar with Excel, a task which is just a few quick mouse clicks to do for us proficient in spreadsheet work. Same with performing CPR: it takes more time to explain, describe and write the process than to actually do it. . .

WAI/GTR function is the quick and easy solution, a "training wheel" that some retain for the "flick of the wrist" convenience to read. But that battery powered convenience is not worth it if you have to back it up with a SPG because of synch problems or signal loss. Might as well discard the WAI and keep the reliable practical SPG then, applying what you learned about gas consumption & management in the first place and should've been proficient in doing all along. . .

 

[Lorenzoid]

I guess this kinda depends on the diving (and abuse) that your kit suffers. For me, they're nowhere near robust enough. Hence, why I stated that in my opinion.

To me, "robust enough" would mean at least as robust as the rest of the computer--or perhaps the rest of my kit. I bought all that stuff based on a belief about how often it might suffer a failure, and if it fails whether the failure is serious or not. That thinking translates right down to having steel buckles rather than plastic, for example. I bought into the idea that I should have steel buckles even though only maybe once in 10,000 dives someone might step on my plastic buckle and break it. I'm sure I have set the threshold for the robustness of my gear higher than necessary to keep me safe, but this is part of the mindset that I have acquired over the past few years since making a decision to get more serious about my diving/safety, and I'm not going to ratchet it down now.

 

[DevonDiver]

To me, "robust enough" would mean at least as robust as the rest of the computer. .

True.... and also consider the location of the equipment; coupled with the relative likelihood and force of damaging contact with the environment.