Can we rely only in a computer?

[jhelmuth]

Wireless AI bothers me a bit, but I'm fine with my AI Uwatec SmartCOM. I've been lead to believe that the RF wireless AI can be problematic in steel shipwrecks, and when in close proximity to same type units.

[DeepTrip]

I'm wondering if there is any hard data to support the opinion that digital SPG's fail more often than analog SPG's. It is a fact of scuba diving that the majority demographic is middle age males who supposedly don't trust technology. Is this just more distrust of "computers"?

Thats probably one of the contributing factor against electronic SPG. I will try to comment from logical point of view.
1. Digital SPG requires battery, analog one doesn't
2. Digital SPG employs additional compartment to keep the electronic part and battery, another point of failure
3. My analog SPG was leaking in a dive. It didn't leak air, but water got into the display. I know I was gambling by using it for 2nd dive, but I'm sure the digital one won't survive the leak.

Benny

[jonahfab]

Any piece of equipment can fail you on any dive, thats why it is important to check equipment and have it anually inspected. I use a suunto cobra and love it, never had any problems. I know guys who have had spg's crap out on them so it just shows nothing is infailable.

[lairdb]

Thats probably one of the contributing factor against electronic SPG. I will try to comment from logical point of view.
1. Digital SPG requires battery, analog one doesn't
2. Digital SPG employs additional compartment to keep the electronic part and battery, another point of failure
3. My analog SPG was leaking in a dive. It didn't leak air, but water got into the display. I know I was gambling by using it for 2nd dive, but I'm sure the digital one won't survive the leak.

Logic isn't always the best tool; Occam's razor is fairly sharp, but sometimes you cut yourself.

Without going through a full fault tree, this doesn't take into account the question of different kinds of failures, how detectable each is, and what the consequences are.

Broadly though, the most common in-water mechanical SPG failure would seem to be stuck-at-3000; the most common digital SPG failures would seem to be total failure. There's a fairly make-able argument that the latter is much more immediately detectable and less likely to lead into an incident pit.

[O2BBubbleFree]

Broadly though, the most common in-water mechanical SPG failure would seem to be stuck-at-3000; the most common digital SPG failures would seem to be total failure. There's a fairly make-able argument that the latter is much more immediately detectable and less likely to lead into an incident pit.

Well put, for comps in general.

WRT wireless, if a wireless comp lost comms it may continue to display the last known PSI/Bar, which would be an equivalent situation to a 'stuck-at-some-pressure' SPG. Either should be readily evident to an observant diver. "hey, I haven't used any air in the last 10 minutes. I gotta figure this out and market it!"

However, I would expect any well-designed comp to realize that it hasn't updated, and give a warning to the diver.

I would argue that the comp is safer in either instance.

[Tom Az]

FWIW I have had 4 wrist mounted computers die on me over the last year. These have all been AI ones. All 4 have had different failures. Once it just went blank. Then no tank psi and so on. Never again will I trust any piece of electronic equipment with my life. Just am glad I had an SPG, old fashioned depth gauge and watch with me at all times. Nothing like backup.

[lairdb]

Well put, for comps in general.

WRT wireless, if a wireless comp lost comms it may continue to display the last known PSI/Bar, which would be an equivalent situation to a 'stuck-at-some-pressure' SPG. Either should be readily evident to an observant diver.[...]

However, I would expect any well-designed comp to realize that it hasn't updated, and give a warning to the diver.

If the wireless comp displays a "lost comm" indicator that is sufficiently obvious, I'd be inclined to argue that it's not equivalent to a stuck needle. A stuck needle's only warning comes when you think "that's funny" and tap on it.

(Incidentally, don't they teach tapping the gauge to make sure the needle vibrates any more?)