PADI tables finally going away?

[The Chairman]

I agree, compasses fail with alarming regularity. I still have 4 out of the 10 plus I have seen fail. One was brand new and pointed almost due West. I simply fail to understand why they are so expensive and still so stinking cheaply built. [/rant]

 

[Ann Marie]

I've had a computer fail. It had failed prior to the dive. The spg was working perfectly on the computer (AI) but the depth gauge had me at 100' while I was gearing up. Hmmmm...if I'm standing on the beach and my computer is with me, how did the beach get to 100'?

 

[kgault]

I would imagine that %99 of all problems with PDCs are them not working at all. With all of my dives on PDCs, I have only had one fail. Of all of the peeps diving around me, I have witnessed one other failure. I have seen more SPGs fail, but only one depth gauge fail and not read right. Of course, the numbers are not equal, and I have yet to see near as many depth gauges as I have PDCs. Most PDCs calibrate at the surface which is something that depth gauges can not do.

But really, if the dive master told me we were on a 60 fsw max reef, then I would expect to see just that. If there is a discrepancy, as there often is, I check against another PDC or depth gauge. I find that dive masters often "lie" as I tell my students. No, they aren't trying to, but my PDC is far more reliable than their dive briefings.

I am suprised to read how few failures you have witnessed for dive computers. You and your friends must be luckier than me and mine

I have sent back many of my own dive computers for failures (many brands), in addition to those for shop customers.

Some of the more interesting failures I have experienced are:
At deco ia computer stopped displaying the top half of every value (BT, Deco Time, Depth, etc).
Calculating Surface Intervals using Nitrox => making a repetitive deco dive require no stops.
Bottom Time accumulation froze for a few minutes.
Clear the nitrogen compartments at the start of each dive.

Many of the older dive computers can be damaged to give false depth readings by subjecting them to dry pressurization.


How do you teach your students to spot the different types of dive computer failures? Using the more conservative output of the two dive computers in a buddy team will limit the possibility of an adverse dive outcome.

Keith

 

[Atom]

People on this thread have said that computers usually don't crap out on you, and fair enough, they usually don't. Even if they do, slowly ascend to 15ft, do a safety stop and you'll be fine. I totally agree up until this point.

Now, consider this scenario :

30meter dive done by a diver who isn't an air hog and its possible for him to exceed the 15min NDL with his AL80 tank.

Scenario 1 (using a dive com) : What if on a dive your dive computer doesn't fail on you but gives you the wrong depth? This is not uncommon judging from what I've read on the forum. Lets say you don't know the tables AT ALL and hence it is safe to assume that you do not know the NDLs at various common depths. The dive com shows you 20meters instead and you hang around past your NDL without realising it, come up, get the bends and DIE DIE DIE DIE.

Some critics might say that he didn't check against his depth against his console, but come on which recreational diver carries backup depth gauges and timers?

Scenario 2 (tables) : You know your tables, you know about the various NDLs (roughly) and you use less fail prone items like brass and glass SPGs and depth gauges and simple bottom timers. I've been using a $15 casio watch as my bottom timer (backup) for 3 years now with no hitch. Its nearly impossible for you to exceed your NDL as you know the NDL in your head and the casio watch won't give you the wrong time (digital watches don't slow down or speed up).

In both cases, if you equipment screws up you abort the dive with no problems. The problem comes when you don't KNOW that your equipment has failed, something that is obvious to spot in brass and glass and quartz, but not so obvious with a fancy dive computer.

Personally, I use a dive computer and love its versatility. I hate to use tables. They're very inefficient. But the simple act of knowing a few of the NDLs in my head and a $15 watch could save my life in the event my dive computer screws up.

You're always more secure with backups, whether your equipment is analog or digital it makes no difference. My depth gauge (analog) failed after 15-20 dives, my computer is fine after more dives than that. This is of course very anecdotal.

But remember... you're almost always diving with a backup, your buddy, if your computer craps out and reads a wrong depth, you'll probably go up with him since he'll approach the end of his no dec time before you.

With all that said, the real solution (to me anyway) would be to have a plan for your dive and know approximately how long you can stay. Using a computer or a table to plan the dive doesn't make that big of a difference.

 

[Sinbad the Diver]

The tables should be taught because even if you fly a computer, it can crap out. Knowing the tables could save your dive vacation.

But I think use of computers should also be taught. People who get out of OW class knowing tables but not computers can buy a nice computer and make some bad mistakes with it.

- Believing the computer senses ACTUAL nitrogen accumulation instead of modeling it
- Disregarding or misunderstanding the computer's instructions, like ascent alarms
- Believing that following the computer's advice makes them awesome deco divers
- Crazy stuff like alternating computers for more bottom time (Yes! Saw that story on another thread. OMG.)

You can't teach how to operate every computer, but they all work the same way, mathematically modeling nitrogen loading. Understanding that will improve diver safety. More understanding always does.

The part of this arguement I can't understand is why can't other's have different goals and reasons for diving and thus have different needs than you? The OP is talking about OW training, not tech, not even AOW. If you are one of the vast majority of divers you want to dive a few times a year, see pretty fish and stuff and go home. When you do that, IMO tables become less safe simply because you are less experienced and the likelihood of making an error using the table increases, to a point where I would think it's more likely than a computer failing. The computer fails, the dive is over as with any other piece of gear you own.

If you like tables and like to use them great, but the idea that there aren't other safe and reasonable ways to dive than what you were taught or the way you dive is silly.



- Believing the computer senses ACTUAL nitrogen accumulation instead of modeling it

Anyone that thinks that wasn't taught or wasn't paying attention in their training, if they were taught tables would they be able to use them if they don't pay attention to something this simple?

- Disregarding or misunderstanding the computer's instructions, like ascent alarms

I believe the OP's point was teach people to use computers, makes this issue less of a problem, but again if someone is willing to dive with equipment they don't know how to use, do think they truely understand tables or spend the time to learn them properly.

- Believing that following the computer's advice makes them awesome deco divers

Nobody said anything about deco, this discussion is about OW divers

- Crazy stuff like alternating computers for more bottom time (Yes! Saw that story on another thread. OMG.)

Again, they are either not trained or ignoring their training, they will do the same ignorant things with tables.

To the OP, there is an agency that already does this, SDI. They are very up front about it and the focus their program on diving with a computer and how to do it safely. They teach that tables exist, they are part of diving and give a basic exercise in their use, both in OW and in the Nitrox course (which they call "Recreational Computer Nitrox Diving" because it's to teach recreational divers how to dive safely with Nitrox).

 

[Tigerman]

...
The computer fails, the dive is over as with any other piece of gear you own.
...

Any other piece of gear can fail all it want and Ill happily continue the dive just fine, except if its my gas supply of course..
Infact as long as Im diving with a buddy and stay no deeper than (s)he does for no longer (providing were both at the same saturation level) than (s)he I dont really need anything but a SPG. Not the way I like to dive, but fully doable and fully possible to do safely.

 

[DevonDiver]

But I think use of computers should also be taught. People who get out of OW class knowing tables but not computers can buy a nice computer and make some bad mistakes with it.

In which case...the arguement exists whether computers are 'core' OW diving equipment or a more advanced, specialist or optional item.

If computers are going to be deemed 'core' diving equipment, that is integral within any scuba divers configuration, then they should be taught at entry-level.

If they are going to be deemed 'optional' or 'upgrade' from the basic equipment configuration, then the appropriate training for them can be taught as an 'upgrade' also.

That facility already exists.... as PADI have the Mulit-Level/Computer Adventure Dive and Speciality Course....

 

[waterman2000]

I am fairly new to diving and I wish they would of gave me a crash course on how to use a computer. I ended up teaching my self.

 

[DiveNav]

I am fairly new to diving and I wish they would of gave me a crash course on how to use a computer......

This is going to happen soon
We are working with several manufacturers to put together comprehensive online classes for real dive computers. We plan to release the first ones by DEMA 09

Alberto

 

[hbhobby]

I was reviewing the tables with a new open water student and found a large discrepency between two different ageny's (PADI and SSI) tables both had comprable bottom times but the surface intervals were over and hour and a half different. weren't all tables based on the navy dive tables? if so why the difference?