Backup Pressure Gauge ... thoughts?

[redacted]

You mean I can't just twist the valve handle all the way open to verify that my air is on?

But how do you check to make sure the "righty - tighty; lefty - loosy" brain cell was not AWOL.

 

[Jorgy]

I saw a what I thought was a neat setup on a live aboard out of Singapore.......

Diver was using a Suunto D9 and SP MK25/S600.......

He had a small 3/4" button gauge opposite his transmitter on his first stage........

On the boat he could check air pressure without linking his D9..........

On his pre-dive check he could verify that his D9 was reading correctly.......

Underwater, if he lost his link or his computer his buddy could read his air pressure......

No hoses, simple, easy to travel with and seemed to work pretty well......

Hope this helps......M

 

[RAWalker]

But how do you check to make sure the "righty - tighty; lefty - loosy" brain cell was not AWOL.

That's why you take a test breath if it is cranked all the way and you notice the pressure fade as you take a breath it is either not open, an empty bottle or something else is wrong.
If I take a breath and the valve is closed I'll see it on my Oceanic Atom 2.0 or VT3 within seconds.

 

[MMM]

I was scolded by a course director recently for not having a backup pressure guage with my AI wrist computer. Since I had a 2nd HP port, I dismantled my old console and just kept the pressure guage and attached it. I run the hose under my arm and BCD so it comes out mid chest and easy to read. I find that it usually registers me with slightly more gas than my computer shows.

 

[scubafanatic]

I was scolded by a course director recently for not having a backup pressure guage with my AI wrist computer. Since I had a 2nd HP port, I dismantled my old console and just kept the pressure guage and attached it. I run the hose under my arm and BCD so it comes out mid chest and easy to read. I find that it usually registers me with slightly more gas than my computer shows.

...not sure anyone had the right to 'scold' you about that, but bottom line is he convinced you to do the 'right' thing.....I know you're all too familiar with wireless AI computers going 'flaky', either not syncing-up before the dive or losing contact during the dive...an old-fashioned SPG is cheap insurance.

 

[RAWalker]

...not sure anyone had the right to 'scold' you about that, but bottom line is he convinced you to do the 'right' thing.....I know you're all too familiar with wireless AI computers going 'flaky', either not syncing-up before the dive or losing contact during the dive...an old-fashioned SPG is cheap insurance.

Anyone that is truely knowledgeable about the use of AI computers within the limits of recreational diving can safely dive without an additional pressure gauge.
You just simply must be aware of the risks present if the computer looses sync and how those risks increase at depth so you can make a proper judgement on how much time to give the computer to re-establish sync or thumb the dive.
Being an AI computer user myself I am aware of these factors and during dive trips will wear a second computer as a backup to computer failure, pack a spare transmitter and SPG in my gear for use with my computer or in the event sync cannot be established. I've never needed to thumb a dive because of the computer. When diving locally I don't feel the need to have backup.
So IMHO and those of many other AI computer users that are well trained in the hazards associated with using AI computers for recreational diving the SPG as a backup isn't a necessity at all. So the right thing will depend on your knowledge, experience, and dive profile and may not include a SPG.

 

[mpgunner]

I think this is a good idea. I have a VT3 and an analog gauge for backup. If the computer fails I can still continue the dive. My dive buddy group likes to do 110+ dives and I like having this option. Sometimes I dive just using the gauge for practice.

 

[scubafanatic]

Anyone that is truely knowledgeable about the use of AI computers within the limits of recreational diving can safely dive without an additional pressure gauge.
You just simply must be aware of the risks present if the computer looses sync and how those risks increase at depth so you can make a proper judgement on how much time to give the computer to re-establish sync or thumb the dive.
Being an AI computer user myself I am aware of these factors and during dive trips will wear a second computer as a backup to computer failure, pack a spare transmitter and SPG in my gear for use with my computer or in the event sync cannot be established. I've never needed to thumb a dive because of the computer. When diving locally I don't feel the need to have backup.
So IMHO and those of many other AI computer users that are well trained in the hazards associated with using AI computers for recreational diving the SPG as a backup isn't a necessity at all. So the right thing will depend on your knowledge, experience, and dive profile and may not include a SPG.

...well, given how much scuba gear one usually dives with, tacking on an SPG is a trivial increase in weight/complexity...so why not? ....by the way, I use a 'hosed' AI Oceanic DataMax Pro Plus II clipped to a right-side D-ring.....a Cochram Gemini 'wireless' AI computer on my left wrist...AND an Halcyon analog/brass SPG clipped to a left-side D-ring....so I have THREE 'sources' of gas pressure on all dives.

 

[fnfalman]

All jokes aside, I'm a recreational diver in open water. If my hoseless AI computer (or hosed AI computer) were to fail, I'd simply surface. How do I know if I will have enough air to do safety stop with? I don't, but since that I'm not doing deco diving, the safety stop is a nice-to-have step and not a necessity.

How can I tell if I go up too fast without the cute little electronic brain telling me? I'd simply watch my bubbles. If I keep up with them or go past them, something is wrong and I need to slow down.

What happen if my SPG or dive computer's pressure sensor were to conk out and give me false readings? Since that I should know what my air consumption rate is with my own style of diving, and since that I have a dive watch on, I should know how much air is left when I reach a certain amount of time. If I were to know that my tank usually lasts me 40-minutes plus ascension & safety stop, comes around 35-minutes and I still see 2000-psi in the pressure readout be they gauge or computer, I think that I better get the hell up. Or if I start to hear the echoing sound in my tank when I breath in and out, that should tell me that my tank is getting low and it's time to boogey.

I like my gadgets but they don't govern my dives. I govern my dives.

And what if my AI computer were to conk out? Will that become the end of my dive for the rest of the day or the holiday vacation? Nope. That's why I carry an SPG console, a dive watch and the dive tables for.

 

[dheuring]

I do a lot of tech diving. I like the redundancy in everything.
I dive 2 computers. 1 wrist-air integrated, 1 hard lined-air integrated, with QD and an additional Old School Needle SPG. If you are diving a computer profile and have a good idea where you are in it, a backup SPG will determine if it is a direct ascent or grab my divers and ascend.
With just 1 SPG, bail and see them at the boat.