Must I abort if computer fails?

[Atom]

One thing to consider though, is that if the computer fails, you need backups for depth and time, so a bottom timer is important to have to back up the computer, and if the computer is an inexpensive hockey puck design, a back up conmputer is only going to be another $100-$150 more than the bottom timer.

I think this is the key take away, especially if you want your bottom timer/depth gauge on your wrist.

I'd still like it if my computer would output a dive table pressure group at the end of the dive, and if that pressure group would be something that could be set as an input into another computer. This could be helpful when you're on vacation and your computer fails (either continue with another computer or continue with table).

 

[Malene]

If your computer craps out during a dive, you don't have to worry about any incompatibility between your computer's concept of the residual nitrogen in your system, and the tables. In fact, you don't need the tables to compute a square profile that takes into account your previous dives.

All you have to do is go into the plan mode of your computer just before your dive and punch in your planned maximum depth. The computer will tell you your maximum time at that depth with a square profile, taking into account your previous dives and your surface interval. If you can remember that number, you can complete the dive on backup gauges if you lose the computer during the dive.

That's a lot of "if"...
I think that in most cases, the diver did not plan that his/her computer would stop working. Without a back-up plan and unless it is the first dive, I would abort the dive. What is one missed dive against an accident?

I would also have a back-up computer. I think it is the safer, simpler solution (yes, diving is an expensive activity ! )

 

[Garrobo]

Although I use two computers, one in a console and the other on my wrist, I don't really depend on them entirely. Mostly out of curiosity as to my actual depth and the water temperature. I keep an eye on my pressure guage and watch. If my watch craps out I always have a computer to look at. No matter what my computer says I always do my safety stops exactly the same. If I am down around 120-130 feet I do a two minute stop at 70ft, a two minute at 50ft a two minute at 30ft and a three minute at 15ft. At shallowerdepths, say 60-40ft, it's the same routine on the way up. Manytimes I have other divers passing me on the way up since they don't take as much time as I do. While I am hanging around I check my computers to see if my ascension plan coincides with their information. Worksfor me.

 

[boulderjohn]

I'd still like it if my computer would output a dive table pressure group at the end of the dive, and if that pressure group would be something that could be set as an input into another computer. .

Which table? There are a number. Different computers use different algorithms that are not necessarily compatible with any specific table, let alone another computer from another manufacturer.

If you have a second computer, just wear them both when you dive and all problems are solved.

 

[Peter Guy]

If you have a second computer, just wear them both when you dive and all problems are solved.

Or learn to use a different recreational profile decompression strategy (for example, "Minimum Deco") and then the only "computer" you need is the one between your ears and the one on your wrist becomes ITS backup. As long as you know your depth(s) and time(s), the ascent profile is easy.

 

[The Kraken]

ScubaSailor,

It's refreshing to see someone think for a change.

the K

 

[scubadada]

If your computer craps out during a dive, you don't have to worry about any incompatibility between your computer's concept of the residual nitrogen in your system, and the tables. In fact, you don't need the tables to compute a square profile that takes into account your previous dives.

All you have to do is go into the plan mode of your computer just before your dive and punch in your planned maximum depth. The computer will tell you your maximum time at that depth with a square profile, taking into account your previous dives and your surface interval. If you can remember that number, you can complete the dive on backup gauges if you lose the computer during the dive.

Exactly what I used do. I never had to use it but could have. Of course, this does not help you for subsequent dives with regard to residual nitrogen. For the past 5 years, I've carried a backup computer. I've never had to use it either, but sure could. This would nicely take care of subsequent dives.

Good diving, C

 

[halocline]

The solution is a redundant computer. Not a buddy's computer, their profiles may not match (we already discussed computer sharing) but an actual second computer that has been on every dive.

Richard

This is a "more gear" solution to a gear failure problem. While redundancy is certainly crucial in life-threatening situations like an overhead environment, an extra computer when the first one isn't a necessity is not IMO the right way to think about this scenario.

It's simple; if you plan dives and execute your plan, there's no problem finishing a dive with a computer failure in recreational diving. In this case, use your buddy for depth/time info and complete the dive. If you want to increase your chances of not getting a DCS hit, do what's prudent on all aggressive NDL profiles; take an extended safety stop.

People seem to think there is some magic line between NDL and required deco, as if there's a specific point, that the computer somehow knows, at which you will either get bent or not. There isn't. There's a range of risk that increases as you get more aggressive. This is why A) different dive computers use widely varying algorithms, and yet none is statistically any safer than any other, and B) it's good dive practice to a few things about basic decompression theory, particularly what kinds of deco obligations are typically incurred when someone slips from NDL into deco. That way, you can fulfill those obligations regardless of which side of the non-existent-magic-line your computer might be on.

There's a parallel here with gas management skills; while a redundant SPG could be considered useful in some situations, most experienced divers are able to have a reasonable idea of their gas consumption. Good gas management comes from awareness and planning. N2 loading/offgassing is really not that different.

 

[SCUBASailor]

Thank for all your responses. I knew it couldn't be as simple a just aborting the dive. I can see instances where it might be necessary, but also many times where a decent dive might be salvaged.

 

[rstofer]

It's simple; if you plan dives and execute your plan, there's no problem finishing a dive with a computer failure in recreational diving. In this case, use your buddy for depth/time info and complete the dive. If you want to increase your chances of not getting a DCS hit, do what's prudent on all aggressive NDL profiles; take an extended safety stop.

But if the plan was to ride the computers then there was no plan. Thumbing that dive may or may not be necessary but my point was that there is no practical way to suddenly revert to tables after diving with a computer.

The idea that you can take the computer pre-dive plan (if a diver even wrote it down) and somehow work into a pressure group seems problematic. If it was a viable practice, it would be written down in some agency or manufacturer's manual. It's absolutely certain that I won't do it. Diving is just something to do, it isn't worth taking any risk.

The redundant computer isn't there for redundancy on a single dive but rather as a way of saving a trip.

Besides, how many new OW divers even learned how to use tables? It seems the agencies are running away from them as fast as they can. And the new eRDP won't even work underwater. To be fair, I can't read the tables underwater either. Old age...

In the old days (pre-computer), I would simply write all the NDLs on my slate and with my trusty depth gauge and bottom timer, I was good to go. The nature of square profile dive planning kept me a long way from DCS because all the dives were really multi-level.

I would encourage people to make their own choices. I have made mine.

Richard