Should Shearwater add Air Integration to its computers?

[stuartv]

It comes with different failure modes but I don't think it's "safer" or "less safe" for any practical meaning of the word. As in I don't consider 1/10,000 vs 1/10,001 a practical difference -- someone else's MMV.

I think failure modes for any SPG break down into:

- no reading
- false low reading (by more than the acceptable accuracy variance)
- false high reading (by more than the acceptable accuracy variance)
- lose gas

Am I missing any? I suppose the reading could be intermittent, but accurate. At some point of increasing frequency or period, that just falls into no reading.

If those are complete and correct, I would class 2 of them as being inconvenient and 2 as being safety issues.

False high and lose gas are safety issues. I am skeptical that the likelihood of those on mechanical versus wireless AI is a much difference akin to 10,000 versus 10,001. It seems to me that those two together would yield a much higher incidence of safety-related failures on mechanical gauges. But, that's just a guess in the face of my own lack of hard data or even long-term experience.

Thus why I continue to ask the people saying WAI is not as safe to support that statement with some hard data - or even "soft" data that is based on years of experience.

Anyway, we clearly agree that wireless AI is safe and reliable enough for anyone that wants to pay for it to use. Not that that means anything to anyone else... LOL

 

[DevonDiver]

I asked Andy this over in another thread, but it seems relevant to pose the question here:

- What did you use for a depth gauge 30 or 40 years ago?

When I started diving (1991), I used analogue depth gauges. I still have one of them, wrist mounted, that I wear occasionally (it still works).

- Which is more important to you? Knowing your depth or your tank pressure? I mean, many of you are so experienced and plan your dives so well that you don't really need to look at your pressure gauge at all, right?

I tend to check tank pressure at logical stages during dives. This is merely to confirm my prediction. Those stages might be on initial descent, on reaching the bottom, at the mid-way turn point, 5 minutes prior to the end of planned bottom time. On a wreck penetration, I will also check gas before entering a new compartment/section and, definitely, before passing restrictions.

Depth is checked during descent, on reaching the bottom... and whenever bottom depth changes (especially on wrecks... as part of learning the layout). On ascent, I'm obviously checking depth for stops; especially if blue water.

- Do you carry a mechanical depth gauge now? If you are an instructor, do you require your students to have a mechanical depth gauge for backup or is it okay to have 2 electronic depth gauges and no mechanical?

Yes, I often carry a mechanical depth gauge. That's a personal thing... a quirk... and it's not something I require. I also wear a dive watch. The two analogue gauges for a tertiary back-up. Electronic gauges; computers or bottom timers are fine, for me or students.

I find that depth gauges are often the first component failure in dive computers. I've suffered double computer failure before. As I always wear a dive watch, it's easy to sling an analogue depth gauge in my pouch, or on my forearm, for a very reliable contingency.

And, lastly, if you do not carry a mechanical depth gauge, what is your rationale for trusting the depth readout on your computer, but not trusting a pressure readout on your computer?

Simply, I don't trust a depth reading on the computer. But I wear, at least, two computers/bottom-timers, so I can cross-reference and confirm the info I am relying upon. I guess my analogue depth gauge provides some reliable 'voting logic' when those electronic gauges read differently.

 

[AJ]

[QUOTE="DevonDiver, post: 7596014, member: 82070But I wear, at least, two computers/bottom-timers, so I can cross-reference and confirm the info I am relying upon. [/QUOTE]
Is'nt that exactly what this whole discussion is about. It seems to me there are two groups in this discussion:
1. We trust on our electronic instruments. We want them to tell us what to do.
2. We use our instruments to confirm what we experience what is happening and if our plan is still valid.

Roughly speaking group 1 is rec, group 2 is tec. Both options are fine on their own. Problems arise if group 2 would follow group 1 way of thinking. Things could go very bad with deco or cave dives with complex gasmanagement. Am I right or wrong?

 

[The Chairman]

Aner]d then there are people (maybe a different set of people?) that are strident in their insistence that tank pressure has no place on the screen of their dive computer.

There's a FIGJAM principle at work here: "If I don't dive it, sell it or teach it, it must be crap!"

For a few divers, the only way to show that they are techier than anyone else is simply to disparage others for how they dive or what equipment they use. It's nothing but a FIGJAM response that's thinly disguised to show that they, and they alone are the expert in the thread. It's tiresome and you can spot them by their OtT (Over the Top) responses that attack others and their decisions. If you don't know what FIGJAM means, click the link below, but it's NSFW!!!

Spoiler

**** I'm Good: Just ask me!​

FWIW, I don't dive a Shearwater because it is not AI. I don't like lollipops when I sidemount. I dive with two PDCs, one on each wrist and two transmitters, one on each tank. There's also a small button gauge on each tank, but I really don't need them. I far prefer this over dangling or protruding SPGs that seem to catch on almost everything. I also went to a less techy PDC that accommodates two transmitters. I understand that there's a tech PDC coming out that will support multiple transmitters and you can bet that I'll be going that route when it comes out.

BTW, the easiest in water failure to avoid and the one I see most often is a leak on the SPG spool. I have yet to see a transmitter leak.

As an aside: my first depth gauge on my first dive in 1969 was a red ribbon. Kudos if you get it.

 

[stuartv]

Is'nt that exactly what this whole discussion is about. It seems to me there are two groups in this discussion:
1. We trust on our electronic instruments. We want them to tell us what to do.
2. We use our instruments to confirm what we experience what is happening and if our plan is still valid.

Roughly speaking group 1 is rec, group 2 is tec. Both options are fine on their own. Problems arise if group 2 would follow group 1 way of thinking. Things could go very bad with deco or cave dives with complex gasmanagement. Am I right or wrong?

I don't think so. I think there are 3 groups:

1. We don't trust any electronic instruments. (this is a pretty small group)
2. We trust an electronic pressure gauge for depth, but we don't trust an electronic pressure gauge for tank pressure.
3. We trust electronics for depth and tank pressure. (a number of people in this group still don't actually use AI, but for other reasons - e.g. cost)

BTW, the easiest in water failure to avoid and the one I see most often is a leak on the SPG spool. I have yet to see a transmitter leak.

Funny! I think I posted earlier in this thread that my only failure I've had, in my vast 1 year of experience , is my SPG unscrewed itself just enough for the spool to pop an O-ring.

 

[The Chairman]

Funny! I think I posted earlier in this thread that my only failure I've had, in my vast 1 year of experience , is my SPG unscrewed itself just enough for the spool to pop an O-ring.

Somehow I just can't picture an SPG unscrewing itself! Was it trying to escape? This is definitely an operator error and I'm sure you learned from it. As a rule, the only fitting that is finger tight on my regs are my second stages. I've learned to insure that they are screwed all the way down before each dive. The instinct when they do leak, is to simply tighten them up, which will nip the o-ring. So, I turn off the offending reg, unscrew the second stage, screw it back on and then re-pressurize. That said, the best way to handle this is to avoid it by checking the fittings before I dive. It's just a part of my routine now. If I encounter a leak while diving it's all on me anyway, so it's best to own the failure as my own.

 

[stuartv]

Somehow I just can't picture an SPG unscrewing itself! Was it trying to escape?

Probably. Who would want to be MY SPG?!

It was an SPG that I bought brand new, pre-assembled as part of a complete new doubles reg set.

I did learn from it, in that I didn't put a wrench on any of the connections in the reg set after I received it. I assembled it with the rest of my rig and verified that it was working before I got in with it. In the future, I will put a wrench on pre-assembled gear like that to make sure it's tight, not just finger tight.

The SPG backed itself off after about 5 or 6 dives. It's normal to turn the SPG to face me, so I can read it, so I can see how, if the connection to the HP hose wasn't tight, I could have been slowly unscrewing it over time - particularly if I turned the gauge with the cylinder pressure off.

I'm just glad it popped a few seconds after pressurizing the reg set during pre-dive assembly, instead of during a dive. I had a spare spool O-ring, so it was only a couple of minute delay instead of ruining a dive.

 

[DevonDiver]

In terms of what AI can, or cannot, do.... here are two safety checks I perform on equipment prior to diving:

1. Positive/Negative Pressure Test (Pre-dive check). When I set up my equipment each day, I do a positive/negative pressure test on the system. Amongst other tests, on stage of this is to pressurize the reg, turn off, walk away and then have a coffee. After the coffee, I will return to the rig and see if the SPG needle has dropped. If so, it indicates a lack of integrity in the gas system.

2. Pre-Dive Reg Check. Breath from both 2nd stage regulators, whilst watching the SPG needle. Both regulators should deliver gas, but watching for needle fluctuation also indicates potential 1st stage/valves issues that might only manifest on descent.

How would using AI impact my ability to conduct those functionality tests before committing to a dive with my equipment?

(not a loaded question - I am genuinely interested in how AI users satisfy themselves on equipment functionality pre-dive, and whether AI hinders these checks, or whether different processes exist, or none?)

 

[undrwater]

While I don't frequently go get coffee after I've set up my gear, I have been known to have a conversation or two. When I return to the gear, I am often curious if there has been a change in pressure (frequently attributed to a change in tank temperature after it has been removed from the car). The computer will show a difference. The computer will also show a fluctuation if you breathe when the gas has been shut off or is restricted.

 

[The Chairman]

How would using AI impact my ability to conduct those functionality tests before committing to a dive with my equipment?

My alarms go off if the air is restricted. I know because I've tried breathing on my reg with the tank barely cracked when I first went to wireless AI. I have to say I was pleasantly surprised. Of course, on sidemount, it's a lot easier to make sure everything is open completely simply by spinning valves.