Back up computer

[MMM]

Hopefully I've hit the right forum for this question. Here's the deal. When I was certified, computers weren't exactly commonplace and for me it was a non-issue since I blew through a tank of air long before my bottom time for tables had been reached. Later, I bought a Tusa computer (not nitrox compatible). Then, a few years later, I bought a Suunto Cobra and used the Tusa as a back-up. Then I got nitrox certified and so while I could use the Tusa as a back-up on my non-nitrox dives, it wasn't any good on the others, however it was fun to use it to see what was going on with the divers in the group using air. But sometimes, I'd end up locking it out.

So I concluded that I needed to get a nitrox capable computer for my backup. (I may still take the Tusa along just so I can gauge what's happening for divers on air.). Here's my question. Should I get another Suunto for my backup (it will need to be a wrist computer so probably a Vyper or Mosquito)? Pros are that it should closely parallel my Cobra and surfacing because the wrist computer is clear isn't going to be particularly helpful unless my Cobra is also since it won't perform its full functions on subsequent dives. Cons are that Suuntos are pretty conservative so if I buy something less conservative, I may know I'm OK to surface on a dive even though my Cobra isn't clear...just that I'll have some challenges using my Cobra on my subsequent dive. I think I've just talked myself into getting another Suunto, but would be interested in others' views.

 

[Jason Ooi]

Sunto Cobra for is nitrox ready mixtures 21% up to 50%, I don't thing is necessary buy another computers as a backup, just simple buy a Uwatec timer.
I used VR3, Uwatec timer as a backup plan reliable and cheap.

 

[bperrybap]

I guess it depends on what failures you are trying to be able to recover from.
Not that having a backup computer isn't useful, but
when you have an air integrated computer, just having
another non air integrated computer isn't good enough to
recover from many common failures.

A backup computer will only be able to provide backup
for those functions that it does.

In your case the Cobra is your SPG.
So if the cobra totally dies for some reason, you no longer
have an SPG. If you are under water the dive is over and
it is time to start ascending.
If you have a backup computer,
you could use it for depth monitoring and a safety stop timer
but you could also use your buddy for that as well if you had to.

If it dies before you dive (during trip travel) or between dives
on a trip (somebody drops tank on it),
You are kind of SOL even if you have a backup computer.

Unless you can scrounge up an SPG, you are done diving
even if you do have a backup computer.
However, if you can find an SPG (most dive ops will be able
to find one for you or rent you one), you will be able to
continue diving using your backup.

One area that a backup would help is for battery replacement
during a dive trip.
The Cobra doesn't remember settings during battery replacement,
so if the battery died and you had the battery kit and
you feel skilled enough to replace
it (to get your SPG back), you'll be done diving for 24 hours
unless you have a backup computer to use for the remainder
of the trip.

Another area that might be helpful to have a backup
is "lockout" or "permanent error" since it appears that
the SPG function continues to work during "permanent error".
If so (you'll have to verify this), and if the backup computer
were more liberal, then if for some reason the Cobra got
locked out, you could use your backup and use the SPG
function of the Cobra.
A drawback to having a more liberal backup is that you
can't really use it for NDL times.

Another use for a backup is for light travel *maybe* dive trips.
Say you are taking a vacation and think you *might* want
to dive. If you have a wrist computer, you could pack only
that instead of all your regs and rent the gear you need if
you do decide to dive.


Just some thoughts.

--- bill

 

[Charlie59]

I see no problem with either of the Suunto units you mention. I used a Cobra until I went crazy and bought a D9. I have always had a Mosquito and it serves as a great back-up. A Mosquito is relatively cheap and has nice functions.

I have never had trouble with my Cobra so a back up may be over kill, but not without merit.

As for the conservative nature of the Suunto, I don't see alot of people staying underwater longer than I do with my Suuntos. No worries whatever you do, enjoy.

 

[wunat]

Personally, I think you don't really need a backup computer. A dive computer should be used as a back up to your concious on the dive plan in the first place. But I think your Cobra is your primary gauges so getting a back up might make sense. The question is just with another computer of much cheaper bottom timer.

Anyway, going back to your questions regarding getting a back up computer, I would probably go with another Suunto unit since they should have the same calculation model so the no decompressioin time you are receiving on both your current Cobra and the backup Suunto should be pretty close if not identical.

 

[NJMike]

I've been thinking about getting a second one, also. I think I will get the same one I already have - an Oceanic VEO 180 Nx - only because it would avoid having to remember two sets of procedures, specs, operation, etc. It's a good computer, also.

 

[Divin'Papaw]

I decided that I wanted something different and more bullet-proof as a backup for my computer (Aeris Atmos 2). I went with a Uwatec bottom timer. Reliable, long lasting and pretty indestructible. In the event my computer dies, I'll simply use my bottom timer and tables until I can get the computer fixed or replaced. I take both on every dive.