Trusting a computer

[Fedaykin]

@Fedaykin: what do you mean by DC?

One should never get separated from his/her body. But to be separated from a group can happen, especially if you have current and/or low visibility. Not a big deal if you are an experienced diver, but it has happened to me .

I have tried to shorten Diving Computer. Sorry for my bad english if DC means a completely different think.

Yes sometimes this kind of separations might happen but what I tried to mean is that this can't be a standard thing and cannot be seen as normal during sportive diving.

Of course there are exceptions. If you are planning it from the beginning than there is no problem. Like a month ago my wife had problems at her ear. Before the start of diving I have told the leader that we might turn back to boat separately if her problem continues. He was knowing that I will have no problem with turning back to boat that he accepted it when his foots were still dry. When her ear started to become problematic I informed the leader and we turned back separately to the boat.

 

[Coztick]

AI= all inclusive (resort)
DC=dive computer

 

[Freewillow]

Thank you, because for me AI, means Air intergration in a console or Dive computor .

 

[drbill]

I didn't get my first dive computer until I had been on SCUBA for over 30 years. I wouldn't dive without one today. However, I dive semi-redundant dive computers, one set fairly conservatively and the other on an average setting, giving me a range of values between the two. I initially started diving two when I had my single computer fail on me at 150 ft during a deco dive. I didn't have enough fingers to count up the minutes on the deco obligation. As far as trusting my computers goes, the only thing I don't trust is battery life so I always have reasonably fresh batteries on a trip.

 

[Centrals]

Two is one and one is none.

 

[Stoo]

It's been mentioned before, your computer is doing real time tracking of your tissue loading whereas a table will only do your deepest,

"Technically" this isn't quite correct. What the computer is doing is tracking your depth and time, and offering a decompression profile based on some specific algorithm. (JohnnyC, I know you know this, but I wanted to mention it for the "less informed"...)

I know this sounds like splitting hairs, but it's important to understand this and make adjustments to account for whatever unique traits that you, the diver, might have... Old, fat, old AND fat, dehydrated, tired, cold, working hard... These are all important factors that computers do not track (with the odd exception) and which can seriously alter your decompression profiles.

They have yet to come up with a computer that actually tracks the real-live-flesh-and-bones diver's tissue loading. It's all just a theory after all...

 

[JohnnyC]

You're right, it's an estimation of tissue loading based on depth, time, gas mix, I don't know if any take temperature into consideration yet, but yes, the distinction is important. Thanks for pointing that out, I should have worded it more clearly.

 

[Jonn]

"Technically" this isn't quite correct. What the computer is doing is tracking your depth and time, and offering a decompression profile based on some specific algorithm. (JohnnyC, I know you know this, but I wanted to mention it for the "less informed"...)

I know this sounds like splitting hairs, but it's important to understand this and make adjustments to account for whatever unique traits that you, the diver, might have... Old, fat, old AND fat, dehydrated, tired, cold, working hard... These are all important factors that computers do not track (with the odd exception) and which can seriously alter your decompression profiles.

They have yet to come up with a computer that actually tracks the real-live-flesh-and-bones diver's tissue loading. It's all just a theory after all...

That's the idea behind the heart rate monitor some fancier computers come with. It's not exactly a fat-o-meter or old-o-meter but it (supposedly) gives the computer some idea that you are not the ideal navy swimmers in a chamber the algorithms were originally based on. Would be nice to see how Scubapro calculates that...
But even if you have a cheaper unit you can usually ad some conservatism manually if you think you need it.

 

[Stoo]

"Fat-o-meter" would certainly be a big selling feature. I'd love to be the marketing genius tasked with making that sound fun.

You're right about the heart rate thing. In light of so many fatalities in recent months of old geezers, I wonder if we'll see one where you enter your age as well as your mix. The elliptical trainer in my basement requires that and lowers my target heart rate accordingly. It's about the only benefit of yet another birthday. :-(

In all seriousness, a heart rate reading combined with age could provide a meaningful parameter for a computer to adjust conservatism.

 

[kcprofessor]

First off, I may be an old fuddy-duddy, but I teach all my students tables. Aside from the fact that they should not rely on a divemaster guiding them, there are several reasons. First, learning table use teaches a bit about tissue loading and residual nitrogen. I don't go into decompression theory, compartments, half-times, etc. as I don't want to fry their brains. (that's what the Science of Diving class is for!) Secondly, computers give you a reasonable estimate of your deco staus at the point in time that you look at it. You can't plan tomorrow's dives on it. If you have a reasonable idea of where you are going, you can at least get a rough plan with tables.
After that, I tell them to get a computer, since it will be more accurate and they now cost about the same as a good bottom timer and depth gage. As for me, I always use a backup, even if it's only a no deco dive. If I want to do a repetitive dive and one craps out, I can keep going. Had that happen on at least three occasions and it wasn't a battery issue. Just in case you think two "identical" computers will give you the same reading, consider that all of the data presented is based on time and depth and depth sensors have a variance. I have had two otherwise identical computers give depth readings that varied by 6 feet, but they were 3 inches apart on my arm.