Am I the only one that dives with 2 computers?

[halocline]

I never use two computers, but I do tend to plan my dives and I have a good idea of how conservative vs aggressive they are. If my computer broke down on the first day of a trip to Cozumel, for example, I'd be perfectly happy diving the rest of the week with just a watch and depth gauge. But, I'm very familiar with the profiles I dive there and know that I'm nowhere near mandatory deco.

Computers do nothing to prevent DCS, they only give you the data so you can dive in a way to minimize risk for DCS. Computers know nothing about your actual N2 loading or a variety of other factors in taking a hit, like physical fitness, dehydration, etc. Any competent diver should be able to plan and execute profiles that are WELL within NDL limits. And studies show that an extended (10minute) stop at 10-15 ft is extremely efficient at safely off gassing in recreational profiles. So if your computer goes belly up, dive a reasonable profile and spend 10-12 minutes hovering at 10 ft at the end of your dive. Life goes on.

Personally, I think the beav's insistence that divers without a back up computer sit out 24 hrs on "his" trips is really just to make them sit in a corner and consider the consequences for not having spent the money on a 2nd computer. Especially when he was giving them a SPECIAL SCUBABOARD DEAL!!!!!

 

[KBDNP]

I am a recreational diver and dive with a wrist computer and another dive computer on my gauge--- was taught by tech divers. It comes in handy as my wrist computer malfunctioned in Bonnaire last month so was glad I had the gauge. Have also set up previously one for air and one for Nitrox so that even if diving nitrox I could decide to follow the more conservative

 

[Centrals]

In that case your answer of 115' for 63mins is perfectly acceptable.

---------- Post added September 11th, 2015 at 09:40 AM ----------

Please note: We always dive nitrox, especially on a live-aboard. We may choose a lighter mix for deeper dives.

You didn't mention it in the first place.
How deep is the 'deeper' dive?
BTW, what would you do in your given example?

 

[beaverdivers]

How deep is the 'deeper' dive?

It just depends on the site. 110'+

BTW, what would you do in your given example?

I would continue diving because I always dive with at least two dive computers.

Here's an example:
Please Note: This video began half way through the dive. This dive's plan changed once the whale shark showed up which maybe a shock to some of you:shocked2:!
This 6 minute video is raw & unedited. Watch at your own risk. The depths ( 40' - 100' ) were determined by the whale shark. This dive was not a solo dive, I was with the juvenile whale shark the whole time!

What would you do if your only dive computer failed at the beginning of this video?[video]https://youtu.be/s0NvZi7P0pM[/video]

 

[scubafreakIN]

Two is one and one is none...

My primary is a Nitek Q, with an Aeris Manta as backup (in gauge mode if it's a deco dive). Before I needed a multi-gas computer, I used the Manta as primary and an XR1-NX as backup.

Your thinking is sound in that it's nice to know that if one fails, your dives can continue unchanged. Reverting to tables is an option, certainly, but as with all table diving, will result in seriously shorter bottom times.

If your back up is in gauge mode, is it still monitoring nitrogen load? I was under the assumption that gauge mode is just that, gauge only, leaving you with only ONE computer monitoring tissue compartments...

 

[stuartv]

If your back up is in gauge mode, is it still monitoring nitrogen load? I was under the assumption that gauge mode is just that, gauge only, leaving you with only ONE computer monitoring tissue compartments...

The manual for my Atom explicitly says it does not track tissue loading when in Gauge mode. However, I don't understand why they do that. I don't see any reason why I couldn't still set it for whatever mix I'm breathing (as long as its Nitrox, since my Atom doesn't support trimix) and have it track the tissues, even though I would not be asking it to tell me NDLs or deco obligations.

That said, I can see where it would be an extremely rare circumstance where doing that would really be of any benefit.

As it is, my Atom seems to be less conservative than my Petrel, so I'm planning to dive them this weekend with the Petrel as primary and leave the Atom in Dive mode, instead of Gauge mode. I suspect that any dive that the Petrel approves of will result in the Atom being fine, too. I.e. the Atom won't lock out or tell me I've blown a deco obligation. That is, of course, as long as I do the same gas switches on the Atom as I do on the Petrel.

 

[Lorenzoid]

The manual for my Atom explicitly says it does not track tissue loading when in Gauge mode. However, I don't understand why they do that. I don't see any reason why I couldn't still set it for whatever mix I'm breathing (as long as its Nitrox, since my Atom doesn't support trimix) and have it track the tissues, even though I would not be asking it to tell me NDLs or deco obligations. . . .

With the computer in normal mode, you could put a piece of tape over the part of the screen where it displays NDL, and then you would have what you describe.

 

[Dhboner]

The manual for my Atom explicitly says it does not track tissue loading when in Gauge mode. However, I don't understand why they do that. I don't see any reason why I couldn't still set it for whatever mix I'm breathing (as long as its Nitrox, since my Atom doesn't support trimix) and have it track the tissues, even though I would not be asking it to tell me NDLs or deco obligations.

That said, I can see where it would be an extremely rare circumstance where doing that would really be of any benefit.



As it is, my Atom seems to be less conservative than my Petrel, so I'm planning to dive them this weekend with the Petrel as primary and leave the Atom in Dive mode, instead of Gauge mode. I suspect that any dive that the Petrel approves of will result in the Atom being fine, too. I.e. the Atom won't lock out or tell me I've blown a deco obligation. That is, of course, as long as I do the same gas switches on the Atom as I do on the Petrel.

Gauge mode is exactly that...gauge mode (as in depth gauge mode). It is no longer a PDC it is simply functioning as a depth and timing device (I run my Petrel in gauge mode a lot). If you want your tissue loading tracked you cannot use a computer in gauge mode...because...well it would be in gauge mode

 

[Lorenzoid]

Gauge mode is exactly that...gauge mode (as in depth gauge mode). It is no longer a PDC it is simply functioning as a depth and timing device (I run my Petrel in gauge mode a lot). If you want your tissue loading tracked you cannot use a computer in gauge mode...because...well it would be in gauge mode

Exactly. The very definition of "gauge mode" is not tracking tissue loading. However, I think I see what stuart is getting at: a computer in gauge mode could just as well still track tissue loading yet not compute or display any NDL value or give you any indications (alarms, lock-out, etc.) of your tissue loading relative to NDL. In other words, tissue loading could be tracked internally, transparently to the user.

 

[stuartv]

With the computer in normal mode, you could put a piece of tape over the part of the screen where it displays NDL, and then you would have what you describe.

Except for the part where it could potentially go into lock out due to missed deco obligations.

Gauge mode is exactly that...gauge mode (as in depth gauge mode). It is no longer a PDC it is simply functioning as a depth and timing device (I run my Petrel in gauge mode a lot). If you want your tissue loading tracked you cannot use a computer in gauge mode...because...well it would be in gauge mode

Just because the manufacturers (at least one, anyway) decided to define Gauge Mode as not tracking tissue loading, doesn't mean a PDC couldn't do it. They could have just defined Gauge Mode to be a PDC that does not display an NDL, does not display deco obligations, and, thus, never locks you out for any kind of violation.

If you program in your mix, the PDC in Gauge mode still has all the information it needs to track tissue loading and, thus, for example, possibly let you use it in Gauge mode for a deco dive in the morning with your Tech diving buddy and then take a nice long SI and do a Rec dive in the afternoon in Dive mode with your lovely/handsome significant other.

Writing down a definition (for Gauge Mode) in a manual does not suddenly make it where things can only work that way.

In other words:

you cannot use a computer in gauge mode...because...well it would be in gauge mode

No, the reason I cannot do it is because they decided to program Gauge mode that way - even though they didn't have to.