PADI not teaching dive tables anymore?

[Dr. Lecter]

Tables will always work, computers may fail.

A fine expression containing a kernel of truth: printed wet notes will always display the data written on them (assuming you can see them and don't lose them). But it glosses over the fact that an ascent plan requires three things -- ascent profile, timer, and depth fix -- and tables provide only one of those. I suppose you could try to use just the tables to do a free ascent, guesstimating stop depth and time... but you'd probably be so far off that the tables would be irrelevant.

Tables require at least one (bottom timer) or two (watch and depth gauge) other working pieces of gear just to do what a computer does. Each of those pieces of gear is an independent failure point--if you're going to bring along a digital bottom timer, then why not just bring along an extra computer? And of course, all this assumes that when the tables come out, your brain or some other piece of redundant gear has preserved the dive data you need to confirm that the ascent profile provided by the tables fits what you've done up 'til that point.

Tables have their place. I do write out planned and contingency profiles before I do a deco dive. But I recognize that my wet notes, dive watch, analog depth gauge, and brain all combine to provide (at best) a sloppy, multitasking-required tertiary ascent plan. Which is why I bring a backup computer, too, and can't quite let something as simplistic as "tables will always work" pass without comment.

 

[drrich2]

Tplyons:

Nowadays, the tables are a backup for me, but for practice, I still plan/dive with a computer, but calculate pressure groups and oxygen exposure using tables during my SI. I know several other divers that do the same.

Definitely not my experience, so I looked over your posting a bit, and noticed you are in Jersey. Any chance you dive locally? Are the divers you're referring to doing wreck dives &/or roughly square profiles?

Richard.

 

[lowviz]

...//...Tables require at least one (bottom timer) or two (watch and depth gauge) other working pieces of gear just to do what a computer does. ...//...

Terminal tables are nice in that all you need is a working SPG to tell you (in get me back alive terms) what "time" it is. Your SAC (RMV) is the timing device, and it tends to run conservatively fast when things get stressful.

 

[Dr. Lecter]

Terminal tables are nice in that all you need is a working SPG to tell you (in get me back alive terms) what "time" it is. Your SAC (RMV) is the timing device, and it tends to run conservatively fast when things get stressful.

That's a nice theory. I do wonder how well the method you describe would compare in accuracy as against counting one-one thousand...two-one thousand... to yourself.

Regardless of whatever kludge you think will get around the need for a timing device for tables to be any more useful than 'gee, I guess I'll just go up nice and slow, until whenever I run out of air at 10' is', you still need a depth fix. Perhaps you'd like to suggest that one can roughly tell what depth they're at based on ambient light, temp, currents, how buoyant they feel, and the smell of the seawater?

 

[lowviz]

That's a nice theory. I do wonder how well the method you describe would compare in accuracy as against counting one-one thousand...two-one thousand... to yourself.

Regardless of whatever kludge you think will get around the need for a timing device for tables to be any more useful than 'gee, I guess I'll just go up nice and slow, until whenever I run out of air at 10' is', you still need a depth fix. Perhaps you'd like to suggest that one can roughly tell what depth they're at based on ambient light, temp, currents, how buoyant they feel, and the smell of the seawater?

-you sound a lot like theory rather than practice.

 

[Lorenzoid]

I'm reading the on topic replies about the value of tables vs non with interest and getting my hands on the new training materials. What I have had enough of is those skimming my comments and misrepresenting them.

The first sentence of your post accused me of "conflating" tables with deco thoery, or in laymans terms suggesting there is a relationship between the two things. I put the citations there for the benefit of the new divers who may be interested, and to illustrate that there is a relationship between the two.

It really has nothing to do with the discussion, but you brought it up. Perhaps you'd like to clarify your original post?

Maybe I misused the word "conflate." I meant that tables and deco theory, while certainly not unrelated, are not the same thing, and teaching one doesn't teach you much, if anything, about the other. I believe this is the point that some others immediately made. I'm in the camp that believes there is little about deco theory that is readily picked up as a result of learning tables, and to the extent that one can pick up something useful about deco theory from learning tables, there are surely better methods for teaching that aspect.

Citations for benefit of new divers--I see. It's a sad state of affairs if there are divers who used tables in the PADI OW course and didn't understand that there is some underlying relationship between tables and decompression (that is, the basic concept that one's body absorbs and releases nitrogen in some relation to depth and time). I suppose there may be some!

 

[lowviz]

...//... counting one-one thousand...two-one thousand... to yourself.

Did that on the Sea Lion in winter. Pretty linear.
View attachment 146152

 

[Dr. Lecter]

-you sound a lot like theory rather than practice.

Instead of responding to my points you want to put them on the table and measure? That's so cute. I'll leave the digression here, then.

 

[lowviz]

Internet history shows that you spoil for a good virtual fight. You aren't worth it.

---------- Post added January 29th, 2013 at 06:39 PM ----------

Reviewed your recent history, nothing of value.

 

[RJP]

Tplyons:


Definitely not my experience, so I looked over your posting a bit, and noticed you are in Jersey. Any chance you dive locally? Are the divers you're referring to doing wreck dives &/or roughly square profiles?

Richard.

The vast majority of people that dive locally here in NJ (which means wrecks) fall into two groups:
- People who dive their computers
- People that cut custom schedules using V-Planner or similar

The only people I've ever seen diving locally (and I crew on a dive boat, so I've seen an awful lot) using agency-provided tables were taking a class. And it's been quite a while since I've seen that. eRDP's are the norm in recreational classes at the local quarry.