Air Integrated Dive Computers and SPG's

[SanDiegoSidemount]

Depends on what fails, though. Right?

If the only thing that fails is tank pressure you're probably OK with an analog SPG as backup, but if the computer battery dies, even having a backup depth gauge probably means you're not diving your plan as a minimum. Did you check your NDL on the RDP before diving, or did you expect the computer to be there until the end of the dive?

My analog backups would be there to help me abort the dive safely. If it's the first dive of the day I'd need help calculating a safe second dive on an RDP if the first wasn't planned that way - bottom time & depth, etc. Even if you fix your computer it probably isn't reliable for planning the next dive since it wasn't there for the first.

Or not, tell me where I'm wrong.

You're not wrong at all, however, different people use computers in different ways. How you use the computer will dictate how screwed you are when it fails.

If you rely on your computer to give you on-the-fly NDL and track your N2 loading across repetitive dives, then you are totally dependent upon it. You'd better carry a second computer if you don't want to take a 12 hour break after a failure, or have a buddy who's diving all the same profiles with you.

On any dive, computer or not, nobody should enter the water without knowing their NDL for the planned depth. So with backup depth/time (yours or your buddy's) you should be able to finish the dive safely, without much urgency. In this case, it would be your choice whether to thumb the dive at the failure or finish as planned. (Of course, how many divers omit this basic pre-dive check?)

What happens after a computer failure depends on how you manage your repetitive dives. I personally use min deco, so my computer is just there to give me depth and time. (And gas pressure if I'm using my rig with the AI sender.) So I could carry on using the normal min deco repetitive calculations.

If you rely on your computer for repetitive dive profiles and have no backup computer, maybe you could reconstruct your repetitive dives with tables and info from your buddies? Seems pretty iffy to me. If you really care about your health, you'll want to sit out for 12 hours.

This issue (as well as the OP's original question) comes back to understanding the consequences and fall-backs if a critical piece of gear fails, and the risks (or inconveniences) you are willing to accept. Some divers don't think through failure points much, and accept more risk. I'm probably guilty of over-thinking failures, and being more risk-averse the older I get.

I think we can all agree we want to come back alive from our dives. Beyond that, it's a matter of personal preference.

 

[DanLW]

I dive both so that if my digital does fail, I can still go diving.

While diving, I cross check every 500psi to make sure everything is agreeing. That way, a failure in either can be detected early on if the readings start radically diverging. I mainly got the AI for convenience and so I could track it in my computerized logs. Not to get rid of a hose.

 

[NorCalDM]

I have two AI computers and have about 300 dives on each. I have only had one complete failure and that was before the dive started and since I have a back up no issues "my back up is always with me so no problems with multiple dives". The typical issue I and my buddies have had with our AI computers is that they don't link and can't read air pressure but still fully function as a computer this why I carry an SPG so I always have two ways to read air pressure and if my computer won't link I don't lose a dive that I've flown half way around the world to do.

 

[MWilliamson]

My first dive with my wireless transmitter was a disaster. The computer and transmitter worked great on the surface, as soon as i got to depth (20-30 fsw), they stopped communication. No, tank pressure reading at all.

I had planned my dive, so I knew how long I could stay down, but I didn't know my tank pressure. I thumbed the dive.

The next week, I went out and bought an SPG as a backup. I check it once or twice a dive just to confirm my computer reading. This week, I'm buying a Oceanic BUD as a backup to the computer.

Redundancy is a good thing. I'm not worried about being in danger. I don't want to lose a dive due to equipment failure. If both fail, dive over.

 

[Lorenzoid]

I recently purchased an air integrated wireless dive computer with the idea that I would remove my SPG and it would lighten the amount of crap I lug around the world and also streamline my setup for diving. One thing that has concerned me a little bit is what happens if the my dive computer fails? Do most people have a simple SPG connected to their 1st stage as a backup, or has the technology in the wireless air integrated (assuming the batteries are fully charged, etc.) progressed to where failures are pretty much non-existent?

Thanks in advance for everyone's input! I really value the knowledge I gain from this board!

Thanks,

D

I do think an AI computer can be a great way for us recreational divers to improve streamlining and conveniently have all their info on one screen. If you're going on a dive vacation, take along a small inexpensive SPG with you as a backup. As a recreational diver, you can always just surface and end the dive if your computer fails. If your AI computer fails, you can surface and end the dive, then disconnect the AI transmitter and connect the backup SPG in its place. Then plan the rest of your dives with tables or use an inexpensive backup non-AI computer (which you can probably rent from the dive op) until you have a chance to have the AI computer problem fixed.

I think having a backup SPG attached in addition to the wireless transmitter is overkill and impedes streamlining, which is one of the reasons you got the AI computer in the first place.

 

[dmoore19]

I think most people who travel to dive have a backup computer. I know I do. I also carry the back up SPG in the dive bag. If I need it I just miss the remainder of 1 dive. I have never had a failure, never been around anybody else that has had a failure of a computer or a transmitter. I replace batteries before the trip. Batteries for my Oceanic stuff are cheap and easy to replace.

 

[Nemrod]

For a "recreational" dive, as in no overhead (which includes deco obligation), then the wireless does not need an analog back up spg. However, the analog unit is far more dependable. If the wireless looses sync or data, the dive is over, up you go. But as soon as one is talking about deco/overhead or dives which might push limits, the wireless is a no go in my opinion.

N

 

[dmoore19]

I highly doubt anyone will argue that point. IF I ever was to dive in an overhead environment I would want an SPG.

For a "recreational" dive, as in no overhead (which includes deco obligation), then the wireless does not need an analog back up spg. However, the analog unit is far more dependable. If the wireless looses sync or data, the dive is over, up you go. But as soon as one is talking about deco/overhead or dives which might push limits, the wireless is a no go in my opinion.

N

 

[TecGirl]

After taking hundreds of people diving here in Hawaii, I have seen wireless systems fail to read tank pressure or read incorrectly too many times. Always have a backup SPG and hose either on and clipped off or in your dive bag. Seen too many people already at the boat , haven't looked at their gear until we were at sea and have a failure. Luckily there is usually a spare reg on board but if you can't read how much gas you have then no diving for you. Granted I am a technical diver and always use analog SPGs and redundant systems in my own gear, nice to have options underwater when the crap hits the fan.


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[susanlouise]

I use an AI computer, and it works most of the time! But sometimes there are problems. I always have on me the non-AI version of the computer and an SPG. No hassle at all and has saved several duves from being aborted.


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