Is a computer actually necessary?

[Diver Dennis]

It's not about smart. On the rec level, it's pretty basic. Min deco, rock bottom, depth averaging and the rule of 120 are all very easy concepts to grasp and employ.

How many rec level divers do you think do more than 10 dives a year? The concepts may be easy but since most divers are vacation divers and only do 10 or less dives per year, a computer makes sense for them. Diving only one week out of 52 can make a person pretty rusty planning a dive and remembering everything from a year ago.

No one, who understands the concepts needs a computer but if you don't dive often, it makes it a lot easier to dive for the majority of divers.

 

[porsc]

well, the main point is that rather you dive every day, or once a year, very few people care to have to stick to such a militaristic dive profile, when most creatures of interest are not going to.
i understand those concepts perfectly well, but would never employ them over using my computer. that would make diving soooo limited, as to take all the fun and freedom out of it. with my computer, i can go just about where i want, and have the freedom to change up what i am doing under there, if there is marine life that takes me in a different direction, or different depths.
i am living in samoa now. if i want to come home for a visit, i could take a sailing vessel, that might make the trip in three weeks (being seasick most of the time, trying not to catch diseases, ect...), because navigation/sailing concept's are fairly easy to use, and because taking a jetliner isn't NECESSARY. or i could buy airfare and make the trip in 14 or 15 hours. which do you think i will use?

sorry guys, i was being pretty sarcastic there to make my points. just having a little fun with ya.

 

[MikeFerrara]

well, the main point is that rather you dive every day, or once a year, very few people care to have to stick to such a militaristic dive profile, when most creatures of interest are not going to.
i understand those concepts perfectly well, but would never employ them over using my computer. that would make diving soooo limited, as to take all the fun and freedom out of it. with my computer, i can go just about where i want, and have the freedom to change up what i am doing under there, if there is marine life that takes me in a different direction, or different depths.

I'm afraid that you don't understand "those concepts" very well because those of us who use them don't worry about sticking to any "militaristic dive profile". I dive where I want or where the cave goes and I do it without a computer.

Your analogies don't work. I don't dive without a computer to make things harder or to do things the "old fashioned" way. I dive without a computer because I don't need one. I started out diving with computers and as my diving progressed I realized that the computer didn't add anything.

I don't dress for shallow diving and then try to make a deep dive out of it by bouncing deep and riding a computer up to try to eek out some no-stop time. Resort diving seems to have evolved into that but I don't need to dive that way. If I want to dive a deep reef, wreck or cave, I dress for deep diving so I can spend some time there and enjoy it.

I'm not getting cheated out of any bottom time and I'm not spending the dive doing any brain-racking calculations.

 

[MikeFerrara]

I'm with porsc, here. I'm sure a computer isn't absolutely necessary, but I'm sure not diving without one.

I think it's great that we can all dive how we want.

Just let the computer keep up with those data points. It can do it better and faster than any diver can.

That sounds good but I'm not so sure that it stands up under close examination. Reference 3 or 4 different tables and note that the NDL can vary by as much as 40% or so...would the real NDL please step forward? Play with some decompression software and nopthe the DRAMATIC difference in ascent profiles you'll get just by changing the user setable parameters...would the "correct ascent profile please step forward? all that precision you think you're getting is a myth. You're trying to measure with a micrometer something that's being cut with an axe.

Dive computers allow the vast majority of recreational divers to get more bottom time safely. And bottom time it what it's all about.

-Charles

Sounds like a straw-man arguement to me. I think the "majority of recreational divers" that you speak of would dive "safer" if they dived more conservative profiles at depths that are well within the limits of their equipment and skills...and they could get plenty of bottom time doing it.

 

[Rick Murchison]

4½ years ago I posted this in this thread.
Haven't changed my mind.
Rick

Is a computer actually necessary?
No.
Useful?
Yes.
Believable?
Sometimes... often... you just have to know when.
The "end-all" and "be-all" to guide you in your diving profile?
Absolutely not!
Do I use one?
Yes, sometimes two.
Rick

 

[ahava]

Electricity is not necessary either.

 

[jviehe]

What will be funny is in the next 10 years, when tables are no longer taught in most OW classes, the answer will be YES. A computer will be required dive equipment, same as an Octo.

 

[Lucy's Diver]

I think it's great that we can all dive how we want.

That sounds good but I'm not so sure that it stands up under close examination. Reference 3 or 4 different tables and note that the NDL can vary by as much as 40% or so...would the real NDL please step forward? Play with some decompression software and nopthe the DRAMATIC difference in ascent profiles you'll get just by changing the user setable parameters...would the "correct ascent profile please step forward? all that precision you think you're getting is a myth. You're trying to measure with a micrometer something that's being cut with an axe.

Sounds like a straw-man arguement to me. I think the "majority of recreational divers" that you speak of would dive "safer" if they dived more conservative profiles at depths that are well within the limits of their equipment and skills...and they could get plenty of bottom time doing it.

You're comparing apples and oranges. The fact that the computer works faster and more accurately than you has nothing to do with that fact that different tables and different computers varying their conclusions in the same profile. Just like PADI tables are more conservative than Navy tables, some computers are more conservative than others. This does not make them less accurate or slower in the calculations that they do actually do. Tables or computers, you are forced to accept the level of conservatism built into that system. What your argument does not address, but which it purported to, is the fact that a computer will (a) sample and calculate more often, thus being more true to its predetermined conservatism level and (b) do it faster and more accurately than a human. If you could take data points every ten seconds during a dive and work out your NDL time in real time in an instant, you'd be diving a computer, but you can't. That fact is not diminished by whatever set of tables you happen to be using at the time.

The axe cut is a cute analogy, and most computers and tables are so conservative that you are making an axe cut. But a computer will but you safely in the middle of the cut. No matter how wide it is human error or inattention can set you to the edge of it.

 

[MikeFerrara]

You're comparing apples and oranges. The fact that the computer works faster and more accurately than you has nothing to do with that fact that different tables and different computers varying their conclusions in the same profile.

I'm not sure you got the point I was trying to make. I doesn't matter if you sample data a million times/second and calculate out to 20 places when the decompression model is just a SWAG.

Just like PADI tables are more conservative than Navy tables, some computers are more conservative than others.

Be careful here. DSAT NDL's are a bit more conservative on the first dive but a 60 minute compartment is used for SI credit making repetative dives less conservative.

Tables or computers, you are forced to accept the level of conservatism built into that system.

No! You absolutely are not forced to accept it. You can always choose to dive more conservatively.

What your argument does not address, but which it purported to, is the fact that a computer will (a) sample and calculate more often, thus being more true to its predetermined conservatism level and (b) do it faster and more accurately than a human.

My point is that the speed and that supposed accuracy is of no real benefit.

If you could take data points every ten seconds during a dive and work out your NDL time in real time in an instant, you'd be diving a computer, but you can't.

I know where I'm at and what time it is. Why would I need a computer to tell me that? I not only know what my NDL (or appropriate ascent is) but I know what it will be BEFORE I even take an action for the computer to sample. You see, I know what I'm going to do and whether or not I think it's a good idea BEFORE I do it. I guess, you just do it and see what the computer thinks about it after the fact? It's a little late then isn't it?

Not only that but I know how much gas that action will require and whether or not I have enough including an adequate reserve should my buddy suffer a total gas loss at the furthest point in the dive. Lets see your dive computer do that. LOL

The axe cut is a cute analogy, and most computers and tables are so conservative that you are making an axe cut.

Who says those computers and tables are so conservative?

But a computer will but you safely in the middle of the cut.

Really? Why do so many divers get bent when using a computer if it puts them "safely in the middle of the cut"? Why would I want to be in the middle of the cut? I know what dives I've done and how I felt afterwards. I know where I set the parameters in my decompresion software and how I pad my decompression given the dive and conditions. How is some computer manufacturer supposed to know or account for that?

No matter how wide it is human error or inattention can set you to the edge of it.

LOL, you mean like if a diver just forgets where he/she is or where they've been? I can see where that would be a problem.

Use a computer if you want. I don't need one.

 

[MikeFerrara]

What will be funny is in the next 10 years, when tables are no longer taught in most OW classes,

I don't think that would be so funny.

the answer will be YES. A computer will be required dive equipment, same as an Octo.

Well, it won't have any bearing on what the rest of us consider as "required equipment.