Shearwater Perdix AI dive log: starting/ending tank pressure?

[NAM001]

But which one? Should they use PADI tables to determine your PG? Or SDI? Or US Navy? Or NOAA? Etc..



It would also be nice just to save you from needing to either remember or carry some other means of recording your tank pressures.

In other words, I go out on a boat for a 2 tank dive. I don't really want to take pen and paper with me and get it out after each dive to note down the tank's start and end pressures of the dive I just did. If I had a non-AI computer and I could go into the dive log on the computer and enter that data, to have it included in the download to my desktop computer later, that seems like it would be pretty handy.



And you were far from the first to do so...

I have been lobbying them for that plus:

- include all stops that the computer will prompt for in its calculation of Gas Time Remaining. Currently, it will prompt for a safety stop, but it does not include the time you will spend at the safety stop in its calculation of your GTR. It only makes a small difference, but still.

- Continue to display GTR after the computer goes into deco. Since you don't tell the Perdix AI what your tank sizes are, it cannot predict GTR using gases that you have not breathed from yet. So, make GTR only displayed in the case that you only have 1 gas Enabled. If you have more than 1 gas enabled, it can't predict GTR, so don't show GTR at all, in that case. But, if you do have only 1 gas Enabled, then I can't see any reason it should stop displaying GTR at the point you go into deco.

The reported gas GTR is not related to the tank you are using. if sensor is on back gas and you are using deco 70 then as the deco runs empty your puter says you still has gas.

 

[Pkishino]

Well, like most people I dive with, we leave our phones at home or in the car.. Sure, now I always note the pressures down on my slate but it would be interesting to be able to input and save on the dc as well as use as a second check during a dive on how your gas usage compares to entered sac rate usage

 

[Joneill]

Well, like most people I dive with, we leave our phones at home or in the car.. Sure, now I always note the pressures down on my slate but it would be interesting to be able to input and save on the dc as well as use as a second check during a dive on how your gas usage compares to entered sac rate usage

I'm confused - we're talking the Perdix AI in this thread and it already captures the pressure info automatically so why would you need/want to enter it manually? The "issue", and I use thst term loosely, is that you can't see that info when you look at the dive log directly on the DC post dive - only when you download it to your PC or to the Shearwater Cloud app on your mobile device.

With respect to checking gas usage during a dive, the Perdix AI displays the real time pressure info and current SAC - so, if you are monitoring that info periodically, what more would you want?

Also, why leave your phone at home or in the car (unless you are shore diving)? Get a waterproof case and keep it in your dive bag. Of course that's just a suggestion and you might have good reasons as to why you wouldn't want to/don't do this.

 

[daduls]

To me, it's odd that they added a feature but did not add the collected data to the log you can see on the DC itself.

While not supercritical, it would be a nice feature ...

Not a big deal - but it would be nice and I would think, rather easy to implement?

The black box on aircraft (that’s not black) captures tons of info that not required to fly the plane or available to the pilots.

Some may have a desire or use for this info, for me it’s not necessary.

 

[scubadada]

I don't need to see the starting and end pressure in the computer log, having it in the download is fine with me. I would like to see Shearwater include choosing a primary cylinder in the download and auto calculation of the RMV. I'm also still holding out for a real GTR that includes ascent, SS, or deco. My 7+ year old Oceanic VT3 does both of these for me, it won't last forever

 

[Pkishino]

Ah, sorry, my bad.. I was taking about non AI shearwater.. Wishful thinking.
Regarding phone.. Cause when we dive we want to get away from phones and anyone reaching us (except captain and backup phone of course..)

 

[stuartv]

The reported gas GTR is not related to the tank you are using. if sensor is on back gas and you are using deco 70 then as the deco runs empty your puter says you still has gas.

Right. That's why I suggested to not show GTR when there is more than one gas enabled. So, if you have a deco gas, you would have it and your back gas enabled and it would not show a GTR at all.

 

[scubadada]

I don't need to see the starting and end pressure in the computer log, having it in the download is fine with me. I would like to see Shearwater include choosing a primary cylinder in the download and auto calculation of the RMV. I'm also still holding out for a real GTR that includes ascent, SS, or deco. My 7+ year old Oceanic VT3 does both of these for me, it won't last forever

Right. That's why I suggested to not show GTR when there is more than one gas enabled. So, if you have a deco gas, you would have it and your back gas enabled and it would not show a GTR at all.

As a rec diver, diving a single cylinder, I'm biased/selfish for my wishes. It is much easier to implement the primary cylinder/RMV calculation and the real GTR when you are diving a single cylinder, with or without light deco.

 

[NAM001]

Right. That's why I suggested to not show GTR when there is more than one gas enabled. So, if you have a deco gas, you would have it and your back gas enabled and it would not show a GTR at all.

That is not necessary, GTR reflects the back gas and that number is always good as long as you are not on the deco tank. the deco tank should have a spg on it and not another AI unit on it. I'm not sure what yo mean by more than one gas enabled. My back gas is the only gas enabled even with 1 or 2 deco tanks of say 50 and 100% with me. I look at it as the GTR is the time remaining to the next gass source which is the surface as programmed. The deco process is not a casual event. it is continual monitoring of time and psi. for a DC to say that you only have 5 min gtr on a deco tank int he middle of a 10 min deco is not real. You have a schedule that says 70 ft 50% for 5 min and 40 ft 3 min on 50% and 20 ft for 15 min on 100%. When you do deco you remove your self from the baby sitte of the DC in regards to the GTR. Now when you return to back gas it becomes a working value. That IMO is why you are locked out from changing the GTR tank during the dive. To work around the the lock out you use the selected GTR tank as your last tank to use. So your whole dive your GTR would be say 200 min till you switch to your final tank that is the GTR tank and then it will read a valid number, say 45 min. The only time you care about GTR is on the last available tank. Most people dive singles and not side mount so the logic of only no GTR selection during the dive is moot.

 

[wetb4igetinthewater]

If your suggestion is accepted then that sensor can not be used on another divers tank. I think that would lead to a problem if not used right.

I’m missing something as that information is available in the desktop app, so I don’t think such an issue exists. Please clarify