computers and dive tables

[cummings66]

Tables and computer models will give you the same profile given the same decompression model. (and I am not talking about a few minutes here or there)

Sure they can do that, but many computers are based on modifed versions of tables to boot, and in the midwest it's hard to dive a square profile. In our lakes the bed is usually not very level and if you're looking at the rock formations you'll defintely dive something other than a square profile.

You can do that, but you'll discover multilevel dives are the norm and for that a table isn't workable, you need to use a wheel for that.

I suppose I should have prefaced the profiles common around here.

So, it all just depends on the profile you dive as to how useful a computer is to you.

 

[Meng_Tze]

Yes and no - you're assuming that you dive a perfect square profile. Further assuming that it takes ZERO time to descend and ascend.

Look at your computer as you ascend and watch it "give NDL back" to you.

I dont dive a computer, but yes, that is what I said. A computer will give you 'where you are now in a dive data'. It is the same model and the same profile... but more accurately tracked. I was commenting on the statement that tables and computers seem mutually exclusive... to leave tables out of the equation when using a computer and visa versa.


If you dive a computer, tables are your back up and will generally be more conservative and thus would be good for use when the computer fails.

I am also not sure that tables use an immediate descent and ascent.....

 

[Meng_Tze]

Sure they can do that, but many computers are based on modifed versions of tables to boot, and in the midwest it's hard to dive a square profile. In our lakes the bed is usually not very level and if you're looking at the rock formations you'll defintely dive something other than a square profile.

You can do that, but you'll discover multilevel dives are the norm and for that a table isn't workable, you need to use a wheel for that.

I suppose I should have prefaced the profiles common around here.

So, it all just depends on the profile you dive as to how useful a computer is to you.

There are ways around this by using average depth calculations rather than max depth. What do you think a computer does when it tracks your actual dive profile...???
But, what kind of modifications do you refer to for the 'tables' in the computer? Maybe my understanding of the coding in computers is off.

 

[Charlie99]

There are ways around this by using average depth calculations rather than max depth. What do you think a computer does when it tracks your actual dive profile...???

Dive computers use signfiicantly more info about the dive that just the average depth. If your instructor told you that computer calculations are based upon average depth, then he is either mistaken or you misunderstood what he said.

Average depth calculations can be used to make a better mental estimate of your decompression status than does a dive table; but in many cases, particularly in reverse profiles, it is a very poor estimate.

Particularly in dives where you have spent time shallow and then deep, average depth calculations will indicate less loading than reality. In other words, average depth calculations for this sort of profile understimate the amount of decompression one must do to safely ascend to the surface.

 

[cummings66]

There are ways around this by using average depth calculations rather than max depth. What do you think a computer does when it tracks your actual

What you have to understand is that this thread is about tables and computers, not averaging or any advanced methods of using tables. Given that limitation what I said makes sense.

I understand what you're saying however.

 

[Meng_Tze]

removed comments to stay within frame of thread

 

[Meng_Tze]

What you have to understand is that this thread is about tables and computers, not averaging or any advanced methods of using tables. Given that limitation what I said makes sense.

I understand what you're saying however.

I agree and apologize.. and should stay within the limits of the thread. I will remove my other statements.....

 

[cummings66]

I wouldn't have removed the comments, it all adds to the discussion and does show that there are other ways to utilize tables. However it's not something to be taken lightly. I would venture a guess and say if you don't know what you're doing in that regards a computer is safer.

By the way, from what I know of the Oceanic computer I have it's based on a 20 tissue compartment and the older Oceanic's uses a 12 tissue compartment and they're both based on Modified Haldanean. It's one of those catch all phrases IMO.

 

[Damselfish]

If you dive a computer, tables are your back up and will generally be more conservative and thus would be good for use when the computer fails.

If you dive a computer and are doing multilevel dives, chances are the tables are not much use for backup - you'll probably be off your tables.

 

[Meng_Tze]

yes you are going to be off on your tables....but I would venture to say that if correctly using the tables... you would be off on the conservative side of things....