Computer dies, why can’t I continue to dive on tables?

[Cave Diver]

People keep indicating that you would have to re-evaluate all your previous dives and work the tables. I don't think that is necessary at all.

Why would you not simply pick the max NDL for your last dive depth and work from there? As long as you know you never went into deco, the prior dives are inconsequential.

Except of course from an oxygen exposure standpoint, but I typically run less than 1.4 ATM of Oxygen for most of my dives and i have never violated my computer wrt oxygen exposure when taking resonable surface intervals, so oxygen exposure would not be a huge concern.

Interesting idea, I see where you're going with that. I'd say part of the answer to your question revolves around the concept of theory and liability. NDL's are based off of a theory. Even though deco is really just theory, the tables and algorithms that are developed for it have statistically been proven to have a good safety record for the overwhelming majority of people.

While you may be willing to assume the potential risk for developing your own theory by translating the information on your dives, that doesn't mean the dive op will be willing to do so.

So, if you're on a liveaboard, I would expect they wont let you try this experiment. But if you're doing nothing but shore diving in Bonaire and you're willing to be a goat, there's nothing to stop you.




* Do NOT attempt the following without a good understanding of tables and deco. If you're stupid, you try it and you get hurt, it's your own damn fault! *

It actually might prove to be an interesting exercise. You could conduct some experiments with "simulated computer failures." Do 3 days of computer diving then pick a dive that your computer "fails" on. From that point on, extrapolate to tables with your method and plan your dives accordingly. Do those dives still using your computer as a backup to your tables and follow whichever plan is most conservative. If the tables keep you out of deco on the computer, you'll have a good idea how well this theory works.

 

[LiteHedded]

this thread sounds like a good argument against using computers altogether

 

[Cave Diver]

this thread sounds like a good argument against using computers altogether

But, then how would you post?

 

[Blackwood]

I have not yet done a liveaboard and not sure when I'll get the chance.

Nor have I, but I was doing 3-5 dives a day (with one 2fer during el norte) in COZ for 9 days.

I did there what I do here:

Dive 1: ascend to half the bottom depth at 30FPM, and go 10FPM from there (30 second stops / 30 second 'slides' per 10 ft).
Repet (less than 90 minute SIT): ascend to half the bottom depth at 30FPM, and go 5FPM from there (90 second stops / 30 second 'slides' per 10 ft).

As long as I stick to my routine, I don't concern myself with residual gas loading. Eventually the slow tissues may start to bite, but they haven't been an issue yet.

My buddy for every dive was using a computer. I was using a "bottom timer" (computer in gauge mode). It wasn't until the last dive of the trip that his went into ceiling mode (which we cleared per my profile, which was an short exponentially-shaped ascent, not its linear buhlmann mumbo jumbo).

Some may not be comfortable with that methodology, but it's working for me.

 

[Thalassamania]

...

It was very interesting to read Thal's post about the AAUS procedure for a failed computer. Taught me a few things. I like to learn new things, and plan to read the entire proceedings. Maybe it is my training as a tech diver, maybe it is being jaded from so many years of running a liveaboard, but in my experience, most divers strap on a tank without knowing what is in it, using regs that just came back from service without testing in the pool, and bought a computer that their sales person recommended based on price or the brand that the store sells, as if all computers were created equal. No one has ever taught them to use it, and they haven't read the manual until 11 PM after boarding. Then they ask me or Melanie to set it for them. This is not an aware diver, this is someone looking for an experience.

...

In the science community ship time costs a LOT of money, $15 to $20K per day, so loosing dives and time due to a computer crapping out is unacceptable. Emmerman and Sharkey's techniques were developed back in the early days of computers, when a single EDGE cost $600 and when $600 was real money. Today I think we'd all suggest just wearing a backup (I can still remember how good it felt when I added a "Skinny Dipper" to my EDGE. The cost of ship time was also why we considered a two hour oxygen washout followed by going back into the water in Group A.

 

[LiteHedded]

but, then how would you post?

oh you!

 

[highdesert]

I still argue for full redundancy ...

We dive with an AI computer on a hose (Oceanic Pro Plus 2), a wrist computer of the same brand/algorithm (Oceanic Veo 250), an SPG, and a watch/bottom timer. Odds are good we'll get through the dive/trip. We've (wife/buddy and I) both had failures of our primary AI computers on an extended, expensive trip, and had to fall back on the backups. I'm glad we had them.

 

[redacted]

this thread sounds like a good argument against using computers altogether

Well, sure. But as long as you are doing planned deco, what difference does it make if you slip in some unnecessary planned deco or planned unnecessary deco?

 

[LiteHedded]

Well, sure. But as long as you are doing planned deco, what difference does it make if you slip in some unnecessary planned deco or planned unnecessary deco?

do what now?

 

[Cave Diver]

Well, sure. But as long as you are doing planned deco, what difference does it make if you slip in some unnecessary planned deco or planned unnecessary deco?

do what now?

He means it doesnt matter if you hang a little bit longer just to be sure.