Any proof that dive computers improve safety?

[tarponchik]

This is, considering the distances, like asking if making calculations with a calculator is safer than doing them by hand, or with a calculator ruler or using the old logarithm tables.

Nope. My question was about existence of supporting evidence, not about general considerations.

 

[tarponchik]

Personally, I feel much safer diving my computer on days I'm doing repetitive dives, especially to significant depth. I even use redundant computers since I've had a battery fail prematurely on a long deco dive. I forgot to strap mine on for my first dive Sat (to 130 ft) and spent the rest of the day trying to compensate for that on my other two dives.

Tech diving is a different story.

 

[tarponchik]

The computer is a data recorder for the chamber operator so there's less guessing when trying to figure out what the diver did.

Now, Terry, I am getting confused. When I asked for stats I've been told that no unformation is ever recordered when a diver is taken to the chamber, so there can't be any stats. Now you tell me that comp contains valuable info for the doc at the chamber. And I know that docs record all info that is relevant to the case. So I incline to think that you are right, but then there must be some stats somewhere, right?

 

[tarponchik]

If you look at dive accident statistics (DAN has good info), you can look at the data and see a wide range of issues. Was the accident "caused" by the computer? I would venture to say that it most cases it was not.

Well, I am looking for a different kind of accidents. Nor for ones that could be caused by computers, but for those that could be PREVENTED by computers. So I would take as an evidence simply a statistically significant difference in odds ratio to have a DCS accident with and w/o a comp.

As for the rest of what you said, I agree with most of it except that non-square profile dives are not that complex with tables. In my estimate, approx. 3/4 of all Caribbean dives are done along corall walls (most of Bonaire, Curacao, Roatan, Utila, Grand Cayman off Turtle Farm and Cobalt Resort, etc) when you go one way at 55-75 ft and then return at 35-45 ft. These dives are fairly easy to plan since they could be treated as two square dives with zero surface interval. I bet comps use the same algorythm.

 

[scubajim311]

Now, Terry, I am getting confused. When I asked for stats I've been told that no unformation is ever recordered when a diver is taken to the chamber, so there can't be any stats. Now you tell me that comp contains valuable info for the doc at the chamber. And I know that docs record all info that is relevant to the case. So I incline to think that you are right, but then there must be some stats somewhere, right?

soo if there are stats and your so interested in proving computers are useless, why havent you got them yet?

 

[FishOutUvH2O]

Well, I am looking for a different kind of accidents. Nor for ones that could be caused by computers, but for those that could be PREVENTED by computers. So I would take as an evidence simply a statistically significant difference in odds ratio to have a DCS accident with and w/o a comp.

As for the rest of what you said, I agree with most of it except that non-square profile dives are not that complex with tables. In my estimate, approx. 3/4 of all Caribbean dives are done along corall walls (most of Bonaire, Curacao, Roatan, Utila, Grand Cayman off Turtle Farm and Cobalt Resort, etc) when you go one way at 55-75 ft and then return at 35-45 ft. These dives are fairly easy to plan since they could be treated as two square dives with zero surface interval. I bet comps use the same algorythm.

Here's the problem as I see it. What you're asking is akin to asking "has the desktop computer made people safer." That's all a PDC is. It's a computer. It runs software. So, it would be the software, more specifically, it's output, and not the computer that you would have to be looking at. Unfortunately, dive computers do not all run the same software. Different manufacturers use different data sets, factors, and algorithms to give the user a theoretical answer to "how much nitrogen has my body absorbed?". And that's the key, every computer is only giving you a theoretical answer. It gets no relevant data from your body (save the Galileo Sol, which can factor in a persons heart rate through a monitor). Science's understanding of an individual's unique physiology and decompression theory isn't to a point that an accurate prediction can be made when a particular person is in danger of getting bent. Right now it's simply based on statistics. In this particular range statistics shows less of a chance of getting DCS, kind of deal. Asking if PDC's have made people safer is literally like asking, "Is it safer for people to use a calculator than a pencil and paper?!" A PDC is just a fancier way of doing tables and an easier method of displaying information, not a device to add more safety to diving. And certainly, not a device that could prevent an accident. But, just for fun. . . Since a computer is only giving you theoretical answers, it could, at best, only prevent a theoretical accident. So, until HAL9000 is written across a computer, they just display information, it's up to the user to prevent accidents.

 

[Web Monkey]

Now, Terry, I am getting confused. When I asked for stats I've been told that no unformation is ever recordered when a diver is taken to the chamber, so there can't be any stats. Now you tell me that comp contains valuable info for the doc at the chamber. And I know that docs record all info that is relevant to the case. So I incline to think that you are right, but then there must be some stats somewhere, right?

The dive computer contains data that may be useful in treating the diver.

This is completely different from any sort of centralized reporting for SCUBA injuries or fatalities.

Terry

 

[Web Monkey]

And I know that docs record all info that is relevant to the case. So I incline to think that you are right, but then there must be some stats somewhere, right?

The doctors files contain individual patient information, however if you're talking about compiled statistics, AFAIK, the answer is still "no".

Terry

 

[drbill]

Tech diving is a different story.

What elicited this reply? I don't consider a 130' dive a tech dive, do you? Although I've done a lot of dives that some would consider tech, the profile on the dives I referred to were all within recreational parameters.

 

[drbill]

Now, Terry, I am getting confused. When I asked for stats I've been told that no unformation is ever recordered when a diver is taken to the chamber, so there can't be any stats. Now you tell me that comp contains valuable info for the doc at the chamber. And I know that docs record all info that is relevant to the case. So I incline to think that you are right, but then there must be some stats somewhere, right?

What he's referring to I believe is that the attendants and doctor at the chamber can review the dive profile in the computer to determine if the diver exceeded safe ascent rates, went too deep, etc.

When one of my dive buddies went to the chamber here on Catalina several years ago, I had already reviewed her computer and thought she was fine based on the recorded dive profile. She thought she had ascended too fast. The doctor at the chamber also reviewed her computer and said her profile was well within parameters considered safe and she was released.