analog vs digital gauge (SPG vs Air Integrated Dive Computer)

[CuzzA]

What does the Petrel technical screen look like compared to the Icon? I've attached some pics for reference of the Icon.

 

[tbone1004]

so the first is the technical screen. Top row is fixed with depth, *you get to choose between fresh/salt/EN*. EN is the "average" of the two, this selection only changes the accuracy of the number, but does not change your decompression obligation. Will show the ascent graph next to it when you are ascending, but goes away otherwise. Your bottom time *the line under the time goes in 15 second chunks so you can see seconds*, the battery gauge, and deco stop depth/time depending on where you are. Shows the surface interval if you're at the surface.

Center row changes depending on what is going on. Will either show your current PO2 if on OC, or your CC setpoints in the middle. The two open spots can show Max Depth, Avg Depth, @+5 *super useful to show your Time to Surface if you stay where you are for another 5 minutes*, deco ceilings, GF99 *your current tissue loading*, CNS clock, Time of Day, Dive End Time *in time of day not duration*, mini compass, Dil PPO2 and FiO2 for CCR. Mine has average depth and time of day most of the time. All of the other info is available during the dive, just not on the front screen.

Bottom row shows what mode you are in, what gas you are breathing, your NDL, and your TTS. Super nice.


Second picture is recreational nitrox mode shows your current depth in big ass numbers in the top left with your dive time in minutes and seconds below it. To the right is the decompression section where safety stops, deco stops, NDL's, and your nitrogen loading graph are shown. Bottom section is again configured by the user where you see what gas you are breathing, and then TTS, CNS Clock, PPO2, MOD, temp, time, Max depth, temp and time, PPO2 and CNS, or Max and Avg depths. You get to choose. One button clicks over to the other screens where all of the rest of the info is easily available, gas switches are two button presses since it automatically goes to the best gas for your current depth, etc etc.

 

[CuzzA]

Nice. For me it really was a toss up between the Petrel 2 and Icon HD. I don't have any buyers remorse on the Icon. Mares has also proved they are able and willing to make this computer backwards compatible and intend on doing firmware updates, same goes for the Petrel. I like that these companies are taking the smart phone approach where you can upgrade the operating system and not have to buy a new device.

I think the future of dive computers is going to be awesome and very exciting. I know some will argue against a computer altogether, but I believe a good computer can also be a learning tool. Especially those that display tissue compartment loading on the bar graph and are also explained in text. This is really great if you want to go back and review how different profiles affect your body.

 

[TMHeimer]

I learned of the purging thing in Rescue Course. I actually can't recall ever seeing anyone else do it.

 

[tursiops]

Deleted - Cockpit error

 

[tcphil]

Agree completely that if you ever look at your pressure gauge, regardless of type, and the pressure is other than expected, something is wrong. Some point out it is likely a training issue. While the more dives one has the more one can predict, we still have the gauges just in case. It could also be some type of undetected failure. If I am taking a single tank down below 100 ft, you bet I will be reading it more often, regardless of training.

Air integrated computers do make it more easy to have all information in one place. Does it make one lazy or less intelligent? It could, but that doesn't mean we shouldn't use them. I went to Nuclear Power School when they were still using slide rule. My first camera had to have all settings done manually. Was I better at estimating reactor physics results and better at capturing pictures than those after me using calculators and auto settings? Probably yes at the gut level, but calculators and auto settings sure took over for most people. Heck when I first started diving as a Navy diver, you knew you were low on air when the J valve clicked. You darn well had to plan your dives correctly then. So glad we have gotten a little more advanced.

I do not use wireless transmitters. Had one new VT 4.1 once for a few months. Tried it with several configurations. Regardless of configuration, during each dive there was at least some period where there was no signal. Was I worried I would magically run out of air? Heck no. But what good is a gauge if you have to hope it is working the few times you want to read it. I know many have had no issues, but many have and this is a demonstrated risk that is just not worth it for me.

I also don't like digital compasses. Not as fast, prone to failure etc. However, connected AI has proven itself pretty well.


Regarding cost. What about used? I see used Pro Plus 2.1s come up fairly regularly and the prices are pretty good. Yes it is big, but not much bigger than some wrist displays now. Battery life is excellent, and they are proven.

I am not a tech diver, so will not speak for or against it under those conditions. For OW NDT, connected AI is nice tool.

 

[scubadada]

For me it really was a toss up between the Petrel 2 and Icon HD.

Personally, I would not choose the proprietary Mares-Wienke RGBM decompression algorithm, conservative with two additional, more conservative options

 

[CuzzA]

Can you clarify this? If I brought both the Icon and Petrel on the same dive what would be the difference in the NDL clock.

 

[Jim Lapenta]

Depends on where you have the shearwater set. Using either gradient factors or vpm-b shearwater gives me virtually unlimited options to decide what level of conservatism I want to use. Paired with my use of multi-deco I decide how my computer uses the info it is given. There are 6 levels of conservatism, 0-5, and I set the parameters. One factor is I'm 56 years old, soon to be, and didn't take the best care of myself when I was younger, so I use a level 2 as a minimum. That would be for say a 40 ft dive in bonaire. Teaching in our local colder quarries? +3. At the bottom of Lake Erie in 36 degree water ? +4. All of those could have very different ndl's depending on the other parameters I set. Max po2, stops, gas, etc.

 

[CuzzA]

So where does the RGBM's least conservative algorithm compare to one of the 5 Petrel settings?