Backup for AI wristmount computers?

[BeachJunkie]

Hello,
I have decided to step up to a wrist mount computer. I have been using consoles for all of my other dives and want to get as streamlined and convenient as possible with my new gear purchases. I've decided on the Oceanic Atom 2 but may try and go with the larger VT3. I don't need a larger display, I'm just a bit nervous with all the negative reports I've heard about the Atom 2. To save myself from losing dives due to computer malfunctions I want to purchase a backup. I don't want to have to spend an additional 800 dollars on another air integrated computer though. If I were to get a cheaper wrist mount and an SPG would this be sufficient? How many LP and HP hose connections would I need on my 1st stage? Any suggestions are greatly appreciated. Thanks for your time.

 

[LowVizWiz]

If you're going that route all you need is the spare SPG in your dive bag. There's no need to attach the SPG and wireless transmitter to the first stage at the same time.

 

[BeachJunkie]

I guess that makes perfect sense. Just call the dive and attach the spg. I guess I was just overthinking it. Thanks.

 

[fppf]

I have over 150 dives on my atom, never needed to thumb a dive yet.

 

[Arizona]

You could wear a plain UW watch on your other wrist and note time of descent and ascent as a back up if a failure occurs. No doubt you monitor your air regularly so as the others suggest just call the dive.

 

[FishOutUvH2O]

If you're going that route all you need is the spare SPG in your dive bag. There's no need to attach the SPG and wireless transmitter to the first stage at the same time.

I dive a VT3 as my primary and this is exactly what I do. Just don't forget to have a wrench in your save-a-dive. I also don't have the option of keeping a SPG attached to my 1st stage. The other HP port is being used by a transmitter for my wife's Galileo Sol. I bought a small Zeagle SPG and an Oceanic Geo computer as my back-up (I bought it after my first VT3 flooded). I think the total was around $350.00. Not cheap, but worth the investment considering I tend to take dive vacations that thumbing one dive to switch equipment would be acceptable, but having to quit diving altogether would be awfully expensive. I'm not the worlds biggest fan of rental equipment, so the investment seemed worth it.

 

[BeachJunkie]

That was basically my thought process. I'm hoping that the Atom won't give me any issues. I just wanted to make sure I had something to cover me if anything went wrong. I was looking at the geo and a small spg as my backup as well. Thanks again for the info.

 

[RAWalker]

I use an Atom 2.0 myself and keep an SPG in my reg bag. The problem with the switch is you can't properly track your residual nitrogen or PO2. For this reason I have a backup computer an Atom 1.0 this allows me to continue diving unless I lose sync with the transmitter. I keep extra batteries and an extra transmitter in my reg bag. So chances are unless both computers die at the same time I'm back in the water after a short surface interval. If both do bite the dust the SPG and tables will be on the agenda for the next days diving.
As for the Atom computers I haven't had any problems with either Atom 1.0, the Atom 2.0 or the VT3 that I've had.
My wife now uses the VT3.

 

[FishOutUvH2O]

The problem with the switch is you can't properly track your residual nitrogen or PO2.

Which brings me to a couple of points that can't be stressed enough:

1. You have to make every dive with both your primary and back-up computer for the back-up to be useful. If you don't, you might as well switch the back-up to gauge mode and plan your next dive as a repetitive dive using tables. I hook my Geo to my right shoulder D-ring because I often wear a compass on my right wrist. But you could just as easily wear it on the other wrist if it's free.

2.You have to remember that if you're diving Nitrox to set both computers to the proper mix.

I also have a 3rd option. My everyday watch is a dive watch. So if worst comes to worst, I use that for depth and time, the SPG, and tables.

 

[RAWalker]

You have to make every dive with both your primary and back-up computer for the back-up to be useful. If you don't, you might as well switch the back-up to gauge mode and plan your next dive as a repetitive dive using tables.

Actually if you don't dive with both then you won't have the time and depth data to use the tables. So you wouldn't be able to use the backup even in gauge mode. You'd have to wait until you are sure your residual nitrogen and/or PO2 were zero to continue diving. A dive watch that tracks depth would allow you to make the switch but if you have the backup computer there is no real switch and would be that much easier.