PADI not teaching dive tables anymore?

[TSandM]

I reread this thread this morning, and it reminded me very much of my first college chemistry class. There was one guy in the class who had this really cool device for doing all the math . . . it was small and had buttons and did the calculations for you. It was made by Texas Instruments, and we all wanted one. But we had slide rules, devices that were really kind of complicated to use and required a fair bit of learning and practice. I'm glad I learned to use one, but they are curiosities today, and the successors to that very expensive Texas Instruments device are now so cheap and so small that you can hang one off your keyring. There is no way that I would recommend that every high school student learn to use a slide rule today -- they actually taught you a fair bit about logarithms, if you understood how they worked, but they're really irrelevant in the real world.

 

[Atom]

What does the nitrogen loaded diver, whose computer fails on the surface interval do? Without some manual back-up (tables don't run on batteries), the computer dependent diver is helpless, and totally dependent, on the knowledge and good graces of a better prepared diver or boat crew. Fact is computers are great, but they fail. You need a back-up plan, and "hoping for the best" won't cut it.

You do the same thing you'd do if your depth gauge had failed or if you watch had failed, skip the dive.

In reality, most dive profiles are multilevel. These are trickier to fit to tables, and assuming the diver remember its dive profiles, going from failed computer to table is not something the average diver will be able to do.

 

[DiveNav]

.....In reality, most dive profiles are multilevel. These are trickier to fit to tables, and assuming the diver remember its dive profiles, going from failed computer to table is not something the average diver will be able to do.

Problem solved.

Alberto (aka eDiver)

 

[lowviz]

...//...slide rules...//... ...//...they're really irrelevant in the real world.

But don't forget one of their particular charms. You could get your answer correct to three decimal places while being off by orders of magnitude. Since this was so easy to do, we were taught to estimate our answer before we took out the 'ol slipsticks.

Then computers happened and estimating became an endangered art until graphing calculators recaptured the day.

The ability of a dive student to estimate the end of a successful dive from any point along the way is what a lot of this discussion is about, isn't it?

 

[TSandM]

Yes, but the only way a table user can estimate without the tables is to have used them enough to know roughly what they are going to say, before they say it -- and the same is true of the use of a computer. It's not difficult to find some very rough methods of estimating no-deco time (the rule of 120 comes to mind) and if your computer is WAY off what that comes up with, you'd recognize it. Way off in the too-conservative direction is only annoying, as it shortens your dive; way off in the other direction has potential for harm, so it is more important to recognize those errors. But most computer malfunctions aren't miscalculations. The commonest failure modes are complete failures -- the battery runs out, the screen fails, the computer floods, or somehow otherwise becomes inoperative. The one exception is the person who fails to reset the computer to air after having used Nitrox, and that's one place where recognizing the bad information is really important. It was that error (in the other direction) that made me stop using a computer.

 

[ScottyK]

January 26th, 2013 at 09:58 PM ----------
I'm sorry no one has taught you how to do the same thing with a computer. If you take the new PADI OW course, you will learn how.

I know how to do it both ways, and am fairly certain that I have the information I need now.... Thanks to you and all who took the trouble to answer...

---------- Post added January 27th, 2013 at 02:05 PM ----------

Does that chip on your shoulder effect your buoyancy/trim?

Nope, trims me out perfectly.

Maybe a thread with a guy asking a serious question about training for his children is not the place for a snarky, smart @ss comment. Does your lack of common sense ever effect your diving experience???

 

[wildlifephotog]

I used to carry my tables (inc nitrox) on every dive, on the assumption that if my computer failed I could use them as a backup. Earlier in this year was my first ever failure, at 25m, in Bonaire. I didn't use the tables, I ascended at a regular rate, did a safety stop, and finished the dive.

When we're doing minimum deco or 'no stop' diving, that's how it works. Hence using a dive computer is probably more important than knowing how to work it all out manually.

Now if you're doing a deco dive, where you don't have the option to just ascend, then clearly one of the options is to take (a different set of) tables and a bottom timer, but equally you could take a backup computer.

Time's moved on. I no longer carry my tables, and while I quite like teaching their secrets and how to understand them, my students don't need to know and some of them aren't so fond of the mechanics.

 

[lowviz]

...//...Now if you're doing a deco dive, where you don't have the option to just ascend, then clearly one of the options is to take (a different set of) tables and a bottom timer, but equally you could take a backup computer....//...

No.

You could also teach to the dark side and inform your students that they have a graded (increasingly effective) set of options that are available to them. Start with the 10 min omitted deco procedure. You are a dive professional, I am not. Please offer something of substance...

 

[boulderjohn]

My very first dive trip after certification, back in another millennium, was to Cozumel. I was a brand new diver trying to figure out how diving in the real world worked. In accordance with the local law, we were required to follow a DM. To cut to the chase, I quickly realized that the tables could not be used on the dives there. The only way I could use tables on those (multilevel) dives would have been to leave the group and ascend much earlier than they did. On the boat, the rest of the dives laughed when they saw the tables in my hand. One told me it made a passable Frisbee if I wanted to get some use from it. I bought a computer. I do believe that in all my dives, the time I brought my RDP out so very futilely was the only time I have ever seen a diver actually attempt to use one on a dive, other than when required on a training dive. It seems wise to me to train people for the tools they will actually use.

 

[Badge353]

Having just gone through the knowledge based section of PADI OW\, I can say I never saw a table. We were thought some computer but mainly using the the eRDLml as a backup to the computer.