Dead computer - No backup

[donnad]

just to make sure i'm thinking correctly. i have a non-air integrated computer, and an SPG. now...........if i also wear my dive watch, and turn that bezel right before descending.......that will give me the length of time of my dive, and if i take note of my max depth of the dive, then if my computer went bonkers for some reason.......then using my max depth, and the time of my dive from the dive watch, i could then go to tables, and not have to stop diving for 24 hrs., correcto? ( my hubby uses an air integrated, but is not currently doing anything for a backup. i just wouldn't want to take that chance of having to stop diving.........or actually, what would happen is, he would be able to use my info, and go to tables afterward if his computer failed. but if i were him, i would be using some sort of backup.)

 

[peterbj7]

In normal use the Stinger battery symbol doesn't show. Once it starts to show you're nearing the end, but in my experience you can probably do 4 or 5 more (warm water) dives before it gives out.

And donnad, your thinking is correct. So long as you know what your profile has been to date you can slot into the tables, and so long as you then don't infringe them you can do your next dive after a normal interval. But how many people keep track of their nitrogen exposure so that they CAN slot into the tables when their computer fails? I know I don't.

IMO there's no substitute for a small slate. Write on it the clock time when you started each dive, to aid switching to tables if necessary. The bezel on a watch can be knocked, and most don't have much friction.

And of course carry the tables!

 

[mruseless]

Not just the Cochrans. Any computer that has a mid-level battery, in a warm atmosphere and then put in cold water has the potential for battery failure.

Haven't you ever noticed that it seems to be the coldest, rainest, snowiest day of the year when your car battery fails?

Good point. From now on, I'm going to put my computers in the refridgerator for about an hour prior to the battery test. Seriously.

Now, I know this is going to sound spooky, and it's possible it was my lack of attention earlier, but my battery is now showing 3 bars as opposed to Max yesterday. Is this an example of observation affecting the experiment?

Thinking about leaving it til it gets to two bars before sending it off. I don't normally dive in cold water (although just about to start, if one considers 15C cold) so hoping that it won't go from a 75% reading to 0% when 30m in the sludge with 1m viz.

I have sent in my Stinger on 3 bars, if before a liveaboard trip, since I didn't have a backup computer at the time. If I do the refridgerator thing, I'll probably wait until its at 2 bars to send it.

just to make sure i'm thinking correctly. i have a non-air integrated computer, and an SPG. now...........if i also wear my dive watch, and turn that bezel right before descending.......that will give me the length of time of my dive, and if i take note of my max depth of the dive, then if my computer went bonkers for some reason.......then using my max depth, and the time of my dive from the dive watch, i could then go to tables, and not have to stop diving for 24 hrs., correcto? ( my hubby uses an air integrated, but is not currently doing anything for a backup. i just wouldn't want to take that chance of having to stop diving.........or actually, what would happen is, he would be able to use my info, and go to tables afterward if his computer failed. but if i were him, i would be using some sort of backup.)

You might find that you are beyond the limits for tables even after your first dive or two. There was a thread on this recently:
http://www.scubaboard.com/forums/ba...late-pressure-groups-if-you-use-computer.html

As far as a backup goes, I don't worry about it too much. If the transmitter fails, you could just abort the dive (I have a spare SPG in my repair kit). No need to stop diving unles the whole computer fails, which is unlikely. But I might be carrying a backup computer soon, since now we have 3 dive computers.

 

[peterbj7]

I wouldn't worry too much even if my sole SPG failed (other than for the implications for the next dive). I always have a pretty good idea how much air I have, and I rarely use more than half a tank anyway, so I know I can make a nice gentle and slow ascent. I wouldn't normally just carry on with the dive though, though I have done when I was with a friend on an open ocean dive and I knew his air consumption was around the same as mine. I assumed I had about the same as his SPG showed, knowing that if I was wrong he was nearby with an octopus, and we had no ceiling above us.

But as they say on TV, "don't do this at home"! Do what I say, but most certainly NOT what I do!

 

[mruseless]

I wouldn't worry too much even if my sole SPG failed (other than for the implications for the next dive). I always have a pretty good idea how much air I have, and I rarely use more than half a tank anyway, so I know I can make a nice gentle and slow ascent. I wouldn't normally just carry on with the dive though, though I have done when I was with a friend on an open ocean dive and I knew his air consumption was around the same as mine. I assumed I had about the same as his SPG showed, knowing that if I was wrong he was nearby with an octopus, and we had no ceiling above us.

But as they say on TV, "don't do this at home"! Do what I say, but most certainly NOT what I do!

A half a tank <drool>... maybe someday I'll be there. I come up from most dives with about 900-1000 psi, which is a lot better than I used to do.

 

[CoralSeaMan]

just to make sure i'm thinking correctly. i have a non-air integrated computer, and an SPG. now...........if i also wear my dive watch, and turn that bezel right before descending.......that will give me the length of time of my dive, and if i take note of my max depth of the dive, then if my computer went bonkers for some reason.......then using my max depth, and the time of my dive from the dive watch, i could then go to tables, and not have to stop diving for 24 hrs., correcto? ( my hubby uses an air integrated, but is not currently doing anything for a backup. i just wouldn't want to take that chance of having to stop diving.........or actually, what would happen is, he would be able to use my info, and go to tables afterward if his computer failed. but if i were him, i would be using some sort of backup.)

You are correct. As long as you know the depth and the time you can keep track of your nitrogen exposure (or O2 exposure) with tables. I agree that the bezel might not be all that reliable. Still, if you know the start of your dive you will be diving just like the time before computers.

 

[Charlie99]

I agree that the bezel might not be all that reliable. Still, if you know the start of your dive you will be diving just like the time before computers.

Even without formal SAC calculations, most divers know how long their air lasts at varous depths. This can serve as a sanity check of whether or not the bezel has moved or whether you remember the dive start time correctly.

 

[InTheDrink]

postscript: my Stinger now reads Max again. Must have been having an off day.

Either that or I'm going mad, neither of which is particularly reassuring. Oh well, if the Stinger pulls a fast one underwater, hopefully the voices in my head will tell me my depth

 

[peterbj7]

I once dropped a watch-style computer and it behaved most oddly for a while afterwards. I think the shock had merely dislodged the battery, probably caused a voltage surge, and upset the circuits. After a while it settled down again.

 

[Doc Harry]

The title of this thread says it all "Dead computer - no backup."

The computer should be the backup device, not the primary device for depth/time/gas.

When my computer failed, I slid it up my arm onto my bicep to get it out of the way and never looked at it again. The failure didn't affect my dive whatsoever.