"Best" backup wrist computer?

[BoatingDave]

So I use a Teric with wireless AI, which I love, and have an analog SPG.

Suggestions for a backup computer to prevent me from missing subsequent dives if my computer were to die? I guess AI would be best, but not required. Don't want to spend a ridiculous amount but I'd spend to prevent missing dives....

Thoughts?

 

[RainPilot]

In a perfect world, you would have something that can match the algorithm in your primary so that both are saying the same, every dive. However, shy of getting another Shearwater, that would require a computer with adjustable GF which thins the options a lot, and none of them are really cheap.

The other alternative would be to get a cheapish computer that is more liberal than your Teric settings, so that your Teric will always be the overriding computer (if you have 2, you always follow the most conservative one).

Then, if you do need to use only that computer, you can adjust the conservancy to your normal preference and go from there.

IF you think you may go to technical diving in future, then bear in mind that you will want a custom GF backup for that, and any cheap Suunto / Oceanic etc is going to be very hard to use in that role, except for gauge mode.

 

[BoatingDave]

Yes exactly what I was thinking. I had looked at a Suunto Vyper Novo for example, but the algorithms are different. I would always go with the more conservative computer, but I could imagine that the second could be beeping unhappily if I were following the Teric for some reason....

 

[MikadoWu]

So I use a Teric with wireless AI, which I love, and have an analog SPG.

Suggestions for a backup computer to prevent me from missing subsequent dives if my computer were to die? I guess AI would be best, but not required. Don't want to spend a ridiculous amount but I'd spend to prevent missing dives....

Thoughts?

I would look at the Oceanic Geo 2 or maybe the OCi. I own a Geo2 (daughters backup computer) and 2 OCi's (Daughters main and my Backup and old main). The algorithm of the Teric and these Oceanic's are almost identical. The Benefit of the OCi is it uses the AI transmitter as the Teric, where the Geo 2 has no AI abilities. I found my OCi for $500 3 years ago, so I am sure you can find a deal now. That said, if you need Tri-mix then I'd just buy a second Teric or Perdix.

 

[tmassey]

I have a Perdix set to 40/80 or /85 (I can't remember which). My backup is a very simple one-gas Oceanic Veo 180NX. I've used it as my backup for a dozen or so oxygen- or EAN50-accelerated deco dives, plus lots of others. Because it's a single gas computer, it has to stay in Nitrox when I switch my Perdix to deco gas.

Here's the fun part: I've bent the computer exactly once: on a dive with 19 minutes of O2-accelerated deco. And even in that case, it was 3 minutes from clear (as the computer download later showed) -- even though the Oceanic was simply in Nitrox the whole time! Even 4 dives a day, each below 100': doesn't matter, the Oceanic always has more bottom time than the Shearwater.

I don't actually care if I violate the backup computer: I'm really just using it as a backup bottom timer, but if it *will* record a safe dive profile for me, why not?

So, if you're looking for a backup to a reasonably-configured Teric, to me the Oceanic is one to consider. If you're not doing deco, I highly doubt you'll ever violate the Ocanic before the Shearwater. If you *are* doing reasonable deco, your training should have taken care of fallback options, anyway, so you just need a bottom timer. So either way, a cheap Oceanic will work outstandingly.

 

[Marie13]

Does anyone know how to put the Geo 2.0 into gauge mode? It's my current backup to a Perdix and I'm planning on using it in gauge mode once I start tech. The Oceanic manual is awful.

Thanks!

 

[tmassey]

I can't speak for the Geo 2.0. On my Veo 180, you put the thing into settings mode, then cycle through the different settings. One is Gau Off, which you would click to turn to On if you wished.

Or simply leave it as a dive computer. It will hurt *NOTHING* to leave it in computer mode, and if you wanted you could simply use it if your primary fails. Why not? And if you *do* violate it like I described above, then it's simply in gauge mode for you!

 

[tmassey]

The only time it's troublesome having a single-gas Nitrox-only computer as a backup is when you're diving trimix. I've only done 2 light trimix dives (25/25). For now anyway, Helium tracking is done very differently than Nitrogen tracking, so no matter what Nitrox number you put into the computer the calculations will be purely fictional. In that case, you're going to be limited to treating it like gauge mode.

In my case, I cheated. I ran Nitrox profiles and Trimix profiles that covered the parameters I was going to do on the dive: depth, time, etc. I found a Nitrox profile that was very similar to the profile for the Trimix dive I was doing, and I used that on the backup computer. It was within 2 minutes (and usually to the better) for a wide variety of parameters centered on my target dive.

I do not claim that this is smart, or that *anyone* should do that. But it worked for my application.

 

[stuartv]

The "best" would be another Teric.

The "best" on a budget would be an AI-enabled Oceanic. I have used an Atom in that role for years and it is great for that. As has been noted, it will pretty much always allow you more bottom time than the Teric, unless you set the Teric to custom GFs of around 90/90 or higher. And an AI-enabled Oceanic will read the same transmitter as the Teric, so even if the Teric dies during a dive, you don't have to end the dive early (nor have a backup SPG on your 1st stage).

I'm going to post my Atom 3.0 and transmitter for sale as soon as I can get around to taking some pictures. Now that I have 2 Terics and extra transmitters, I don't have any further use for the Atom. But it has worked fine on numerous tech dives as backup to the different Shearwaters I've had.

Does anyone know how to put the Geo 2.0 into gauge mode? It's my current backup to a Perdix and I'm planning on using it in gauge mode once I start tech. The Oceanic manual is awful.

Thanks!

There is really no need to put the Geo into Gauge mode. The WORST case is that you bend it. That will mean that it puts itself into Violation Gauge Mode. And that is the same as regular Gauge mode except that you can't switch it out of VGM for 24 hours (or whatever the time limit is). In other words, it will put itself in Gauge mode if it gets bent. And, as @tmassey says, you'll have to do some serious accelerated deco (i.e. breathing O2 or some other rich deco gas) before you'll have any real chance of bending the Geo.

 

[stuartv]

The only time it's troublesome having a single-gas Nitrox-only computer as a backup is when you're diving trimix.

For any dive where I have used a non-tech computer as backup, I write my plan down in my wet notes and carry them with me. If my tech computer died during the dive, I would rely on the written plan and depth and time info from the non-tech computer - but not the deco info from the non-tech computer. For that matter, I normally write down my dive plan in my wet notes, regardless. I don't trust myself not to pull a bonehead move someday and get confused about what my planned max depth or max bottom time is. Wet notes are there in case I need to check myself/my memory.