What scenario requires you to need to have a precise measurement of how much gas you have? 100psi is as granular as you ever will need to be. Showing a dive buddy an unfamiliar wrist display to show PSI only causes confuses.
Eyeballing halves is easy, quarters not much more difficult, and I sometimes do one or the other for my own info when I want to be more precise in calculating SAC/RMV. But I agree that knowing I've got 2,123 PSI and not 2,119 is more info than I need. For buddy purposes it's nearest (usually lowest) 100.
You will rarely if ever need to show a team member your depth gauge so the type of depth gauge used has no impact on the team.
In which case the type of display is irrelevant, as long as YOU understand it.
Why do you need to have PSI cluttering your display? This is DIR remember, brain is primary instrument, your pressure gauge is just to check that you are tracking gas consumption correctly. I dont see a scenario for an experinced diver - be it a tech diver or some DM on a cattle boat - to need to check their actual PSI more then a few times. PSI on your depth gauge just adds clutter.
What clutter? At least on the Uwatecs PSI is in small characters at the bottom of the screen, something that I have to specifically focus on to read. Whereas the depth and dive time/run time are the top line in the largest font, which is just what I want. And there's nothing that says you have to have PSI displayed on the main screen, if you find that clutters the display too much. UEMIS seems to be taking this approach, putting it on an alternate screen.
Wasnt the WKKP doing real world stress testing for Uwatec? What purpose does an AI computer serve for a cave diver doing stage diving that rarely touches his backgas? Do you really think any one diving with the WKKP really needs to rely on a AI computer? It's a toy, its not a tool in the toolbox.
Shouldn't all this be in a hog forum or something?
AI computers simply are not DIR, let's not try to shoehorn them into a faux DIR just to make everyone happy...
Guy, those pics you refer to were part of a test for uwatec. The diver was on an RB80 being run by drive bottles, not much backgas usage there FPRIVATE "TYPE=PICT;ALT="Also, mant folks dive doubles in relativly shallow water because of their stability, weighting (drysuit), and options they afford the diver underwater.
They do a lot of testing. Just because a picture catches JJ or Casey diving X or Y gear doesn't imply a particular gear endorsement...
(And yes, they're less dogmatic, but that doesn't mean that anything goes...)
My point was not that they were using it for a test (I'm aware of it) or endorsing it, but rather that they didn't say "Hey, we have absolutely no need for this, it's not DIR-compliant and it introduces an extra failure point, so we aren't going to take it into an overhead environment and put ourselves at (minimal) extra risk." No, they said "Sure we'll try it despite all the above, because it's not a big deal," and they felt comfortable enough to put pictures of Casey wearing such in the "Halcyon - DIR Dive Systems" catalog. And there are also shots of JJ and others wearing multiple gauges in the same catalog. Now, unless you think that they couldn't find ANY photos showing those two (and others) in notional fully DIR-compliant gear for the catalog, I'd say they don't get terribly worked up over the idea of an individual diver wearing redundant gauges.
Just to add a comment on this thread . . . for a variety of reasons that I won't go into, I was in the water with a newer diver today who was briefly diving some borrowed equipment for demonstration purposes. He was distressed because the pressure gauge (which was a Suunto Cobra) was clipped off to his waist strap, and he couldn't figure out how to get it loose. So I came over and checked his pressure for him (which was really unnecessary, as we were in 15 feet of water for less than 10 minutes). I found myself trying to read the screen on the Cobra with it upside-down, and with the pressure numerals being the smallest ones in the display, and it was really irritating. Grabbing an analog SPG, I wouldn't even have had to look at the numbers. I could just have looked at where the needle was on the dial, and that would have been enough.
And that's the beauty of an analog gauge, Lynne, where you're interested less in the specific numbers than in the relative position of the indicator. Speedometers are the same; it matter's very little whether the dial is calibrated in mph, kmh, or furlongs, what you're primarily interested in is that the relative position doesn't change. I see that Uemis has realised this with their AI display, which gives you both analog and digital pressure displays:
Extras / During the dive / Functions / uemis ZURICH / Products - uemis - THE UNDERWATER REVOLUTION
Of course, instead of a 'dial' face you could use a vertical or horizontal bar with appropriate index marks; I've seen some company's computer that uses this for ascent rate, and I think it's an excellent idea. The reason we find reading pointers on round or rectangular analog dials so easy is because we're accustomed to them, not because they're always the best possible display format. [Note: I used to have a girlfriend whose master's was in human factors engineering, and she was splitting her time between Nasa Ames and Lawrence Livermore. Her primary interest was in human perceptual issues, and she was working under an FAA contract at Ames on causes of aviation accidents/incidents. I've always been interested in ergonomics and displays, so I used to enjoy reading the proceedings of the human factors conferences she attended more than she did (but then I didn't have to actually listen to the lectures). And reading accident accounts that were partly or largely due to poor display design, like Three-mile Island, made me even more aware of the issues]
Guy
