Question about air integrated computers and transmitters

[divinh]

I bought an AI computer with the intention of having both the AI computer and an SPG connected, for redundancy. I was recommended that I should only need the AI computer since having the SPG connected as well would create another point of failure. On my most recent trip, the brand new AI computer failed to register the correct air pressure (thankfully before the dive) and I didn't have the SPG with me to just swap out. I ended up borrowing an SPG from the shop and put the AI computer away. It'll be sent back to the the retailer today for repair or replacement.

If I relied upon the AI computer alone, I would have been out-of-luck this trip. I have a wrist dive computer as the main computer and the AI computer was serving as the backup. The wrist computer is more conservative, which is why its the primary. If it's happy, the backup would be happy too; that's the idea.

Primary computer: wrist
Secondary computer: AI computer console

Primary air pressure: AI computer console
Secondary air pressure: SPG to swap out with

 

[scubadada]

To each their own. For the last 9 years, nearly 1400 dives, I have dived a wrist AI primary computer, a wrist computer backup, and a SPG. In that time, I have needed the computer backup, the SPG backup, or both, on only 12 dives. Most of these were my own fault, computer battery, transmitter battery, forgot to put transmitter on alternate reg set. Only 4 dives were lost to a transmitter failure.

I have improved my battery habits, chance of needing backup has probably decreased further. I dive the same configuration today, it is second nature to me. I start my week in Los Revillagigedos tomorrow

 

[caruso]

Depends on your risk tolerance, the type of diving you're doing and access to spare parts. Most importantly how important is it for you not to miss a dive due to equipment failure?

I carry 2 identical AI computers- one on wrist and another in a BCD pocket, and a mini SPG the size of a half dollar on a thin hose.

 

[scrane]

I went wireless AI because I was tired of dealing with an extra hose. But, I carry a small SPG in my kit and the tools I need to attach it to my first stage in case of transmitter failure.

 

[mmerriman]

i have an AI computer, but also a compact SPG

 

[caruso]

3 advantages of keeping the SPG with AI:

1- easy to check tank pressures predive
2- backup to AI transmitter
3- may be easier to check buddy's gas (depending on config)

A mini SPG on a thin hose tucked away behind the left side of the BCD leaves a really small footprint.

 

[purbeast]

Okay thanks for the replies. I think for now I will just get an SPG and down the road look more into AI.

On a related note, for depth, do most people have the physical depth gauges? Or do most people JUST use the computer for that?

Both of the setups I've rented thus far had both SPG and depth gauges.

I will say too, when I did my first attempt at my OW, my new (to me) dive computer (Suunto Vyper Novo) had an issue with the depth sensor and was not registering correct depth, so the gauge there helped for sure. But it's since been fixed and seems to be working fine.

 

[Landau]

I’ve never had a depth gauge other than on a computer. I notice no one above mentions a redundant analog depth gauge though some mention redundant computers

 

[jlcnuke]

Okay thanks for the replies. I think for now I will just get an SPG and down the road look more into AI.

On a related note, for depth, do most people have the physical depth gauges? Or do most people JUST use the computer for that?

Both of the setups I've rented thus far had both SPG and depth gauges.

I will say too, when I did my first attempt at my OW, my new (to me) dive computer (Suunto Vyper Novo) had an issue with the depth sensor and was not registering correct depth, so the gauge there helped for sure. But it's since been fixed and seems to be working fine.

I only use my computer, but I do have 2 of them at all times so I still have redundancy. As you're probably noticing, how much redundancy a given diver wants changes from person to person. On liveaboards, technical dives, etc, you'll find people tend to prefer more redundancy in things that could either impact their ability to keep diving (not knowing tissue loading would make doing the 5th dive of the day irresponsible so a backup computer is preferred by many for instance) or their ability to safely complete the dive.

 

[taimen]

If you are ready to thumb the dive immediately when you get an AI error, you don't need an SPG.
You won't be aborting too many dives with Shearwater AI (pelagic systems transmitter) if you change batteries and installation (transmitter orientation) is correct.