How do you back up your computer?

[ReefHound]

It doesn't an inordinate amount of attention.

It's little different than when a police officer says "do you know how fast you were going?"

Does it take your focus off driving to be aware of what your gauges are telling you and have told you? I don't think so, at least not after one has been driving for a few years. Diving is no different.

Being aware of your surroundings and readings at the time is quite different from committing it to memory for future reference. When I get home from work, I probably won't be able to tell you that at mile marker xx I was going yy mph and had zz gallons of gas in my tank. While I will be monitoring those variables during the drive, remembering them after the drive is pointless. Of course, I don't log my drives.

I didn't mean to suggest that nobody ever records their progress on a slate but within the context of normal recreational diving I stand by my statement that I don't know anybody who does this for the purposes of "backing up" their computer to be able to recreate their profile manually.

 

[texdiveguy]

I agree, but the OP asked "Is there any system people have when diving multilevel to keep up with all the depths and times, and another member asked "Ok how? how do you keep track of the various depths and times at those depths?"

That question isn't covered in any 'basic' training I'm aware of. Sure, most of us use a dive computer, but since the question involves preparations for that computer to fail, "use the computer" doesn't seem like a good answer.

AFAIC, the answer is either:

1. Carry a redundant computer,
2. Make notes of your profile, or
3. Pre-plan the dive, and accurately dive the plan.

If you choose 2, you can either:

A. Do it in your head, or
B. Write it down.

Personally, I find 2A to be far less cumbersome than 2B. If either takes your attention off what you are doing (diving), opt for 1. 3 is next to impossible for anyone at an unknown dive site, and doesn't take into account extenuating circumstances.

Correct........... I was under the impression we had given the OP responses that addressed his question in various forms and options.

I concur that note taking for recreational multi level diving is very cumbersome. For many of us a second dive computer is the best back-up.....but even with the addition of this piece of redundant gear one should always be aware of the fore mentioned basics.....with this and that 'gray' matter between the ears a diver should be able to ascent safely barring any other conflicts out of the ordinary. A dive computer failure is nothing more than a slight inconvenience easily addressed and responded to.

Happy-safe and always fun diving!!

 

[NudeDiver]

A dive computer failure is nothing more than a slight inconvenience easily addressed and responded to.

It can also be a big expense. When mine failed, it cost some $450 to replace. If you're out on a liveaboard, without a backup - you can sit out for 24 hours and then "start over" with tables - a real drag, esp. for whomever you are diving with, if they are using a computer and then get limited by your tables.

For local diving - do whatever. But for trips, which can be very expensive, a backup computer really seems like the way to go.

 

[texdiveguy]

It can also be a big expense. When mine failed, it cost some $450 to replace. If you're out on a liveaboard, without a backup - you can sit out for 24 hours and then "start over" with tables - a real drag, esp. for whomever you are diving with, if they are using a computer and then get limited by your tables.

For local diving - do whatever. But for trips, which can be very expensive, a backup computer really seems like the way to go.

My comment regarded the act of the computer failure during the dive.

Yep it can be costly if you are not properly prepared for such event afterwards. But if you have invested such monies I would also hope one would take prudent safeguards in respect to a back-up dive computer.....I even wear the back-up computer during all those dives.

 

[NudeDiver]

I even wear the back-up computer during all those dives.

Yeah - if you're not actually wearing it, it's just a "second" computer rather than a backup

 

[Blackwood]

In the meantime, I dive with two computers now

Perfectly fair.

While I will be monitoring those variables during the drive, remembering them after the drive is pointless.

I agree. But IF there were a point to it, I have no doubts that you could do it.

 

[ianr33]

It can also be a big expense. When mine failed, it cost some $450 to replace. If you're out on a liveaboard, without a backup - you can sit out for 24 hours and then "start over" with tables -

Why do you need to sit out 24 hours?

Worst case you are Pressure Group N?? after an NDL dive in which your computer died. Just plan your next dive accordingly.

(Its been a long time since I used tables,sorry if I got the letter wrong but you get the idea)

 

[texdiveguy]

Why do you need to sit out 24 hours?

I am betting cause some O/W Instructor told him that.........

 

[NudeDiver]

I am betting cause some O/W Instructor told him that.........

Maybe. I dunno. I don't think we covered the use of computers in my O/W class. But if my computer died on me, and I didn't have a backup, I would be inclined to treat it the same as if the computer had gone into "error" mode. My protocol for that is to wait for 24 hours before diving again.

 

[Charlie99]

NudeDiver, I'll bet that if you really did have a computer failure that you'd apply some common sense, which may or may not have you sitting out for 24 hours.

Whether or not you formally and officially track your profile, after a while you will indeed have a pretty good "feel" for your profile and loading. If you just did a relatively shallow dive and know your loading is relatively low, then sitting out 24 hours is IMO overly conservative. In addition to having a crude mental estimate of how heavily loaded your are or how hard you were pushing up against NDL, you also have other ways to confirm you estimate, such as what your buddy's computer is saying.

Adding some extra time in the shallows (30' or shallower) will compensate for pretty severe errors in guessing at your N2 loading. Indeed, this is exactly how the ratio deco or "depth averaging" guys account for repetitive dives. They just have a minumum SI of an hour or 90 minutes, and then extended the shallow stops.

While it isn't really "backing up the computer", my simple plan for handling a computer failure is to simply assume that I exited the dive in PADI pressure group Z and go from there. The penalty for assuming pressure group Z rather than the correct pressure group is not a bad as you might think. In 30 minutes you will go from Z down to Q .. so if your "real" pressure group were Q, then assuming Z just makes you extend your SI for an extra 30 minutes.

I'll take my backup computer out of the dive bag, pop it into my console and bring it along for the next dive. I'll start using the computer for deco calculations after an overnight break.

Charlie Allen

p.s. There are a couple of assumptions associated with assuming PADI pressure group Z. One is that I assume that I have not gone into deco. If I haven't gone into deco, then the 60 minute compartment is within limits which is equivalent to saying that my PADI pressure group is Z or less. (The PADI pressure groups are based solely upon the 60 minute halftime compartment.) There is another set are rules having to do with 3 or more dives in a day with one or more reaching pressure group W or higher. You only reach these pressure groups through very long dives with relatively shallow average depths. These special rules invoke either a 1 hour minimum or 3 hour minimum SI between dives. I have never approached the requirment for 3 hour SI, even when doing multiple repetitive dives with an AL80 and a SAC just under 0.4cfm.