Are dive computers making bad divers?

[Marie13]

i am a dinosaur. i started diving in 1973 have well over 200 dives and a computer of any kind was just a dream for much of my time underwater. i am with Bob who said the best question is "Can you properly plan a dive?". A dive computer is a wonderful and adaptable tool that can more accurately guide and record your underwater adventures and maybe keep you from harming yourself. Bad divers? A tool does not make a bad diver. Good instruction, thorough training in all your equipment and a humble "always learning" attitude will make a good diver.

You’ve been diving since 1973 and only have 200 dives? I hope that was a typo and you meant 2000!

 

[Akimbo]

i am a dinosaur. i started diving in 1973 have well over 200 dives and a computer of any kind was just a dream for much of my time underwater. i am with Bob who said the best question is "Can you properly plan a dive?".

Tables are quite adequate for working square-wave dives where a diver drops to a worksite and leaves when the job is done or reaches their maximum decompression for the conditions. That is what they were designed to accomplish. How do you plan a typical meandering recreational dive where you follow what is interesting without an excessive penalty?

Imagine you plan a dive to a maximum depth of 60' and you see a whale shark for the first time 32' below. You swim down to observe them but they swim off in 2 minutes. Do you end the dive, recalculate for 100' for a 92' dive and surface much earlier than planned with plenty of gas, or go back to 18m/60' and end the dive when your computer says you are low on gas or nearing the NDL? Non of these options are wrong or dangerous but a computer gives you more time to enjoy your expensive time underwater.

I was talking to some marine scientists that plan very deep dives on rebreathers and are able to productively work their way up the face of walls so their non-productive decompression times are minimal. You can't do that with tables either.

Computers are just a tool like BCs or drysuits. They are not required but can be pretty nice of a lot of dives.

 

[Wibble]

Tables are quite adequate for working square-wave dives where a diver drops to a worksite and leaves when the job is done or reaches their maximum decompression for the conditions. That is what they were designed to accomplish. How do you plan a typical meandering recreational dive where you follow what is interesting without an excessive penalty?

Imagine you plan a dive to a maximum depth of 60' and you see a whale shark for the first time 32' below. You swim down to observe them but they swim off in 2 minutes. Do you end the dive, recalculate for 100' for a 92' dive and surface much earlier than planned with plenty of gas, or go back to 18m/60' and end the dive when your computer says you are low on gas or nearing the NDL? Non of these options are wrong or dangerous but a computer gives you more time to enjoy your expensive time underwater.

I was talking to some marine scientists that plan very deep dives on rebreathers and are able to productively work their way up the face of walls so their non-productive decompression times are minimal. You can't do that with tables either.

Computers are just a tool like BCs or drysuits. They are not required but can be pretty nice of a lot of dives.

Which was the point of @boulderjohn's post #366. If that was calculated with a square profile, it is very much a technical dive requiring ANDP skills.

The reality was it's not a square profile and a computer was used to inform the diver of the deco limits, i.e. to keep within NDLs.

 

[EFX]

Should the title of this thread be "Are dive computers making safer divers"? How easy is it to jump rows or columns with tables and end up in a lower group? Yeah, I know. You can enter the wrong gas or conservatism factor in your DC but if you're that challenged maybe diving is not for you.

 

[2stroketony]

You can strap a spare PDC to a harness or keep it in a BC pocket for most NDL liveaboard diving. The backup is there in case one dies so you don't have to wait 24 hours to dive again — a rule that most liveaboards enforce when your only computer fails.

Of course having them both in view and easily compared is a good idea for more advanced technical dives, which argues in favor of identical PDCs or at least identical algorithms.

Now your talking. Instruments plus a computer or, two computers!!
Easy.

 

[Celt]

Should the title of this thread be "Are dive computers making safer divers"? How easy is it to jump rows or columns with tables and end up in a lower group? Yeah, I know. You can enter the wrong gas or conservatism factor in your DC but if you're that challenged maybe diving is not for you.

It's actually very hard to make a mistake of an entire group as when you're planning dives consistently with tables a mistake jumps out, but there has to be a reason people carry backup computers. Unless of course its to sell 2 computers instead of 1. I don't recall a recommendation to carry 2 watches or depth gauges.

 

[boulderjohn]

It's actually very hard to make a mistake of an entire group as when you're planning dives consistently with tables a mistake jumps out, but there has to be a reason people carry backup computers. Unless of course its to sell 2 computers instead of 1. I don't recall a recommendation to carry 2 watches or depth gauges.

In my experience, the push to have 2 started in tech diving, which is ironic, because tech diving was slow to adopt computers at all.

With recreational diving, if a computer (or watch or depth gauge) fails, you just go to the surface, having lost only the remainder of that dive. In tech diving, if you need a piece of equipment for a dive, then you normally bring at least 2, because you must complete the dive or at least stay down long enough to complete decompression requirements. You must have backups for anything essential. When many tech divers started taking computers, they often used them to back up the normal custom tables for the dive. Then the computer became the primary instrument, and the custom tables became the backup. Then people started using two computers.

For me personally, I went through that all range in tech diving, from no computer at all to computer as backup to custom tables as backup to 2 computers. Once I had two computers for tech diving, it made sense for me to bring them both on recreational dives, too. I have them, so why not? The only thing being wasted is AA battery life. It would not, however, bother me to do a recreational dive with only one of them. The friends with whom I do most of my recreational diving only use one.

 

[scubadada]

...Once I had two computers for tech diving, it made sense for me to bring them both on recreational dives, too. I have them, so why not? The only thing being wasted is AA battery life. It would not, however, bother me to do a recreational dive with only one of them. The friends with whom I do most of my recreational diving only use one.

Ha, part of my post from another thread:

I have never lost part of a dive, a dive, or a series of dives because of a computer or transmitter problem. I started diving a computer in 2002 with an Oceanic Pro Plus 2 hosed AI. I started diving a backup computer in 2005 with a Cochran EMC-14. I switched to an Oceanic VT3 hoseless AI primary computer in 2010 and changed backup to an Oceanic Geo 2, along with adding a SPG. In 2016, I changed the backup to a Dive Rite Nitek Q because I wanted to learn Buhlmann with GFs. I changed the backup/2nd computer to the Shearwater Teric in 2019. The 2010 Oceanic VT3 is still going strong, 1743 dives/1842 hours. Since 2010, I have used a backup computer or SPG on 17 dives, 0.98%

 

[RIHappyDiver]

It's actually very hard to make a mistake of an entire group as when you're planning dives consistently with tables a mistake jumps out, but there has to be a reason people carry backup computers. Unless of course its to sell 2 computers instead of 1. I don't recall a recommendation to carry 2 watches or depth gauges.

Having learned to dive before computers, 1979, we were fine counting on our buddies watch, or depth gauge, if ours acted up. We would call the dive a little early, just to play it safe. I had a watch who’s minute arm started swinging freely during a dive.
Big difference is that it is not recommended to follow your buddies computer. Like boulderjohn, it doesn’t bother me to do a local rec dive without a backup, but I always take a backup when I go on a dive trip. Those trips cost too much to miss out on dives just because a computer acted up on you.

Erik

 

[Celt]

In my experience, the push to have 2 started in tech diving, which is ironic, because tech diving was slow to adopt computers at all.

With recreational diving, if a computer (or watch or depth gauge) fails, you just go to the surface, having lost only the remainder of that dive. In tech diving, if you need a piece of equipment for a dive, then you normally bring at least 2, because you must complete the dive or at least stay down long enough to complete decompression requirements. You must have backups for anything essential. When many tech divers started taking computers, they often used them to back up the normal custom tables for the dive. Then the computer became the primary instrument, and the custom tables became the backup. Then people started using two computers.

For me personally, I went through that all range in tech diving, from no computer at all to computer as backup to custom tables as backup to 2 computers. Once I had two computers for tech diving, it made sense for me to bring them both on recreational dives, too. I have them, so why not? The only thing being wasted is AA battery life. It would not, however, bother me to do a recreational dive with only one of them. The friends with whom I do most of my recreational diving only use one.

I never or still don't carry 2 watches, but on complex deep working dives we had the safety of a standby on the surface who would also have your time. Stops were done on a fixed cradle so you could complete the dive without watch or depth gauge. How would you rate the reliability of modern computer in your experience.