Another Tables vs. Computers Thread

[minnesota01r6]

Lamont, I would agree that a computer may not be the best choice of equipment for technical diving because a computer doesn't know when you switch gasses (unless you tell it), doesn't necessarily use your prefered method of calculating deco obligations, etc.

But, since this is a thread about learning recreational diving with a computer (only gas is air, no deco, most people using PADI tables) couldn't you agree that it is a safe alternative to said tables, or atleast give an example of why it is unsafe that doesn't involve a dive more advanced than an OW certified diver is expected to make?

EDIT: also, if you choose to, please give an example of how learning to dive on a computer and then executing those dives is unsafe rather than just a possible inconveninece, as would happen if your computer broke and you could not dive for 24 hours because you couldn't track your residual nitrogen.

 

[lamont]

Lamont, I would agree that a computer may not be the best choice of equipment for technical diving because a computer doesn't know when you switch gasses (unless you tell it), doesn't necessarily use your prefered method of calculating deco obligations, etc.

But, since this is a thread about learning recreational diving with a computer (only gas is air, no deco, most people using PADI tables) couldn't you agree that it is a safe alternative to said tables, or atleast give an example of why it is unsafe that doesn't involve a dive more advanced than an OW certified diver is expected to make?

EDIT: also, if you choose to, please give an example of how learning to dive on a computer and then executing those dives is unsafe rather than just a possible inconveninece, as would happen if your computer broke and you could not dive for 24 hours because you couldn't track your residual nitrogen.

Honestly I don't care what anyone else does.

NetDoc posted that he thought that not using computers was all based on ego, and that's all I responded to.

I used a computer and my brain for 150-ish dives. At one point I wrote a step-by-step rebuttal of all the "bakers dozen" of DIR reasons why not to use a computer. I would never bother arguing that the use of a computer inherantly makes you an unsafe diver. I would even argue that a computer can be a useful tool for beginning divers provided they don't switch their brains off. OTOH, there are those out there that arguably need to have their computer taken away from them and only given back to them after they can plan a dive without having a crutch. Its just a tool, its not bad or good. Mine annoyed me, so I switched it off. YMMV.

 

[H2Andy]

Why do you say that you have to know decompression theory really well if you dive without a computer?

sorry, i meant "to dive without a computer or tables you need to know deco
theory really well."

i said that because what some guys do is figure out the "logic" behind the deco
stops and times, and then they can "predict" deco obligations for any dive
within paramaters. they don't carry computers or tables with them.

it's way too advanced for me

 

[The Chairman]

NetDoc posted that he thought that not using computers was all based on ego, and that's all I responded to.

That's not really what I said. Great twisting of my words though!

 

[limeyx]

This seems to be the most common problem --- you, Mike Ferrrara, and limyx all have reported this as being the big problem with computers.

When you were diving with a computer, when it was set to the proper mix, did it ever restrict your profile?

The only legititmate complaint I've seen about dive computers forcing a diver into an unwanted profile was a Suunto computer that wanted to see 3 minutes total stop time between 20' and 10'. The particular diver preferred an approximation of a 10fpm linear ascent to the surface, with 1 minute at 30', 20', and 10' so the Suunto was a minute short on stop time. (One can argue whether or not the straight line ascent is anywhere near the ideal shape of deco, but in any case, that's what that diver wanted to do).

-----------------

Good summary of points. I propose another one -----

Does diving with a computer force you to do a profile other than what you would do without it? No.

For a recreational dive, the worst the computer did was to try to make me stop at 15 feet for a safety stop.

For tech, I will never know.

What's the point of bringing a computer if I am doing all the work though? (addressing your final point). Unless it actually gives me something then I dont need it.

 

[limeyx]

Lamont, I would agree that a computer may not be the best choice of equipment for technical diving because a computer doesn't know when you switch gasses (unless you tell it), doesn't necessarily use your prefered method of calculating deco obligations, etc.

But, since this is a thread about learning recreational diving with a computer (only gas is air, no deco, most people using PADI tables) couldn't you agree that it is a safe alternative to said tables, or atleast give an example of why it is unsafe that doesn't involve a dive more advanced than an OW certified diver is expected to make?

EDIT: also, if you choose to, please give an example of how learning to dive on a computer and then executing those dives is unsafe rather than just a possible inconveninece, as would happen if your computer broke and you could not dive for 24 hours because you couldn't track your residual nitrogen.

I think, given the very low proportion of "serious" dive accidents, it's hard to argue a computer is necessarily "unsafe"

However, what does it mean when certain computers (as stated by someone else) can vary on an NDL by tens of minutes? If it were me, I think I'd like to know what is going on. Why dont they all say the same thing for the same dive? Is one diver going to get bent and the other not?

as lamont stated, at an abstract level, I couldn't really care less how people I dont dive with dive. I'm not an instructor or dive professional. As long as I have dive buddies who dive the way I like, what does it really matter to me?

 

[DivesWithTurtles]

To our casual readers and lurkers: Take note that it seems the only folks disdaining the use of computers here (completely aside from reliability issues) are talking about them in the context of technical diving: deco, deep, trimix, gas switches, etc.

BTW, the OP (me) was really asking a question in response to those that suggest that they learned more or understood more about decompression theory by learning to use tables, or that the only way an OW student will understand what's going on in their bodies or in a dive computer was to learn to read tables. The only one that I've seen directly address that was Mattboy way back in post #9. I think maybe this is because I didn't pose the question very well.

Then again, I like the way threads take on a life of their own, and I've been enjoying much (some, a little bit) of this discussion.

 

[Scubakevdm]

What's the point of bringing a computer if I am doing all the work though? (addressing your final point). Unless it actually gives me something then I dont need it.

For most rec diving profiles, a computer gives you more time. Some computers (Suuntos and Dive Rites come to mind) may not. The reason to use both the computer and the tables is that if you have backed your computer up with a table plan, you get to finish the dive based on that plan instead of either continuing blindly or aborting it if your computer poops.

I feel that it is less clever to do decompression dives with a computer not designed for such a purpose, and it is my choice not even to use ones that are made for deco. Generally, my deco dives are made on wrecks on which information concerning the depth of the decks and levels is known prior to the dive, which allows us to come up with a reasonable plan, and to plan for contingencies. I sometimes use a personal computer to develop this plan, but I carry the information on a slate, which has so far proven to be reliable. I'd hate to think what would happen if my slate crapped out on me.

Anyway, it seems like many of the anti computer types are tech folk, and the anti computer arguement is better made when disscussing that kind of diving. If you aren't doing deco dives, I think a computer makes life alot easier and gives you more time with the fish.

 

[DivesWithTurtles]

For a recreational dive, the worst the computer did was to try to make me stop at 15 feet for a safety stop.

Hmmm....

What's the point of bringing a computer if I am doing all the work though?

To give a diver a reasonable estimate of an NDL with credit for a multi-level profile on-the-fly where you may not know before-hand the profile that the dive will present, without doing all the work of keeping track of average depth and calculating an estimated NDL in your head.

Doing little things like setting a nitrox mix or adding your own deep safety stops (remember, we're not talking about tech diving) for a little nicer ascent profile isn't any more work than turning on your air. You do remember to do that, don't you?

 

[DivesWithTurtles]

...
However, what does it mean when certain computers (as stated by someone else) can vary on an NDL by tens of minutes? If it were me, I think I'd like to know what is going on. Why dont they all say the same thing for the same dive? Is one diver going to get bent and the other not?
...

For the same reasons that Decoplanner, V-Planner, Gap, your Ratio Deco, etc., don't pump out the same profile. And you know and understand that, so why ask?