PADI tables finally going away?

[Thalassamania]

In thinking about the replies to this thread in support of teaching tables to OW students, it seems to me that they fall into three categories:
1) The "it's important in principle" reasons, i.e., people should have a solid understanding of decompression theory before using a dive computer, and tables are instrumental in learning that theory.
2) The "we shouldn't ask people to use unnecessary equipment" reasons, i.e., not all divers have access to dive computers, and so all divers must be instructed in an alternative low-tech method of dive planning, just in case they wind up in a situation in which there's no computer for them to use.
3) The "I paid good money for this dive trip and I don't want to miss the next dive" reasons, i.e., what if my computer fails and I want to keep diving?

The response to the first category of reasons that most appeals to me is something like, It's not necessary to understand how an internal combustion engine works in order to safely operate an automobile. Decompression theory is fascinating, but I think a general understanding of it is sufficient for open water students, and further, I think the same level of understanding is needed whether learning to plan dives with tables or with a computer. For those who want more, there are books like Deco for Divers that lay the theory out in non-technical terms without any reference to dive tables.

I feel that is is more than "important in principal" for people to have a solid understanding of decompression theory. Exposing oneself to a hyperbaric environment is a medical decision that (at least within my ethical system) should not be made without the person being so exposed being able to provide informed consent that goes way beyond a vague knowledge that diving may be dangerous and that you can expect a bends rate (with normal recreational practices) of about one in ten thousand dives.

I think that your analogy is fatuous, driving or riding in a car is not a medical decision that may, even if everything is done correctly by everyone, result in injury or death on a stochastic basis.

The response to the second category of reasons that most appeals to me is that we should be teaching what students need. If we are teaching students who have limited or no access to dive computers, then of course we need to teach tables, but if we are teaching students who already own/plan to purchase dive computers or who intend to rent computers for their dives, I see no reason to force them to study table use. We should be teaching what students need and are most likely to use, not what some well-intentioned but misguided it's-important-in-principle view mandates.

Computer and table are two ways to look at the same information. In today's world all divers need to understand how to use both, regardless of what the students think their future diving needs might be.

In response to the third category of reasons, this is where it gets really muddy. Assuming a dive computer fails during a multi-level dive and assuming there is a set of tables accessible to the diver, and assuming the diver has the data from the previous dive(s), yes, s/he could try to plan a subsequent dive using the tables. However, in my experience here, many, if not most, of our multi-level dives that are perfectly okay on a computer violate the NDL on a table. This violation will prevent the diver from doing any subsequent dive anyway, if the table rules are adhered to. So even knowing how to use the tables won't help in most cases, unless the diver has conscientiously tracked average depth throughout the previous dive(s) and can use a rule of thumb, like the 120 rule, as a way to interpolate the data and apply it to planning the next dive according to the tables. For most people, diving is a recreational pursuit. As such it's not worth risking one's physical well-being just to avoid missing a dive. When a computer fails, just sit the next dive or two out. It's the prudent thing to do in the same way that skipping a dive day when you're congested rather than stuffing yourself with decongestants is the prudent thing to do. Yes, some people will try to dive anyway by self-medicating when they've got a cold, and some people will try to do a dive using another means of dive planning after a computer failure. But just because some people do it does not make it advisable.

See previous comment, if divers have the knowledge required to use either computers or tables your entire scenario is irrelevant. So what is that prevents providing both? Divers who are too stupid to learn? Or is it Instructors who lack the willingness or competence to teach? Or is it shop owners who are too greedy to permit their employees the little extra time that it takes? Or ... what?

 

[Pullmyfinger]

I cannot believe that this thread is still going on after 1100 posts. I also cannot believe how strongly some of you cling to the tables.

Yes tables are great, and I still carry mine, but lets be honest that is not how divers dive. And at the end of the day, your average open water student wants to learn how to dive. She does not care about deco theory, as long as she doesn’t get sick.And at the end of the day in practical diving, there is no difference between tables and a dive computer. They are both representations of deco theory that are simple enough for a lay-person to use.

Not all divers aspire to be average divers, I'm not looking at the "average" as my performance standard. I'm willing to spend additional time and money to pursue the better/higher quality training.
For the average diver that is looking for average instruction....there are plenty of average instructors that will provide what they want.
Threads like this one highlight the differences.
Clearly there are different approaches, we all find exactly which one appeals to us.
Computers vs. tables...doesn't matter really, they both work fine. In many ways a computer IS the better tool.....I'll still cling to my tables. ;-)

I'm not disagreeing with you, just pointing out that the average doesn't necessarily represent a "standard" for some.

;-)

-Mitch

 

[*dave*]

In thinking about the replies to this thread in support of teaching tables to OW students, it seems to me that they fall into three categories:
1) The "it's important in principle" reasons, i.e., people should have a solid understanding of decompression theory before using a dive computer, and tables are instrumental in learning that theory.
2) The "we shouldn't ask people to use unnecessary equipment" reasons, i.e., not all divers have access to dive computers, and so all divers must be instructed in an alternative low-tech method of dive planning, just in case they wind up in a situation in which there's no computer for them to use.
3) The "I paid good money for this dive trip and I don't want to miss the next dive" reasons, i.e., what if my computer fails and I want to keep diving?

For me, the tables are a tool. Divers have used them for decades and they are still widely in use today. It's a simple tool to teach, so why not give them that tool? My investment in lecture/discussion time consists of :20 on session 3, :10-20 session 4 and perhaps :10 on session 5. That's less than 10% of available lecture time.

There are divers looking to do single dives. My wife, for example, is totally fine with a single shallow reef dive. She has a Cobra, but it would be just as simple to look at the depth column on a dive table, check the Doppler Limit for that depth, plan the dive and execute it with her watch and a depth gauge. I've known more than a few folks who just want to flutter around a 40' hole for an hour, hang up their fins and do their land thing for the rest of the day. I'm pretty sure they could get by without that $1200 AI Cobalt.

While their lack of correlation to actual decompression models makes them less than ideal for teaching deco theory, they are pretty key component to teaching dive planning that doesn't result in divers flying their computer blind.

The tables are a tool, why wouldn't we give them that tool?

Not necessarily directed at you, Q. Just a couple random thoughts as I read your summary.

TBH, I might want to teach the tables because I'm good at it and I get something of a rush watching the lights go on when students grok the tables. I'm pretty sure I haven't damaged anyone in the process and I can't recall ever having heard a complaint, so I don't see a reason to stop.

 

[Quero]

I've known more than a few folks who just want to flutter around a 40' hole for an hour, hang up their fins and do their land thing for the rest of the day. I'm pretty sure they could get by without that $1200 AI Cobalt.

Yep. And even on much more aggressive dives, I manage to get by without that $1200 AI Cobalt, too!

I know you weren't necessarily engaging me specifically in your post Dave, and I do agree for the most part with what you've said. I'm pretty good at teaching tables, too and have never had any complaints (it's not really hard to teach people how to use them), but in my experience very few people actually do use them once they've been taught how to use them (and tested on their learning). Like most learned skills, without regular use, skill proficiency degrades, so in many ways it just seems like wasted effort when other ways of approaching the knowledge may be more effective in introducing deco theory. After all, the objective is to give students the the information they need to make educated decisions about planning and executing their dives.

If the tables really were correlated to decompression models, I'd certainly view teaching them in a different light. As it is, even when I'm teaching tables, I often get people started thinking about decompression theory by talking about the drying rates of various parts of wet blue jeans, and most people get the idea of theoretical tissue compartments more easily that way than through an explanation of columns of numbers on a plastic table. I've found that the same blue jeans lead-in works for teaching computer use, and I can assure you that my students recall the damp seams of a pair of otherwise dry blue jeans much more readily than the RNT boxes on the back side of the RDP. Before anybody gets all het up about my blue jeans analogy and decides to jump all over me with outcries of "false analogy," let me say simply that I don't stop there--that's just the door to the topic. :glad:

My point is simple: if a particular student is going to not use tables (especially those divers who already know they will be computer users), and if tables are not a particularly good teaching aid to understanding deco theory, I'd rather spend those 45 minutes which would be dedicated to table teaching to engage in discussion on why dive computers are programmed to indicate varying ascent rates, or why many computers take into account water temperature and workload in their calculations. Now if a student wants instruction in table use, no problem! That student gets tables!

 

[AfterDark]

Originally Posted by ekremer
Case 2) Private Boat.
This is where the divers themselves get to choose a spot and do the dive. This is my favorite type of diving
Step 1) find a location, (usually for us it is between 70 and 130 feet.)
Step 2) Dive till either A) gas or B) NDL runs out.
Step 3) return to boat and fish. and figure out your next location. (Usually for us it is between 30 and 60 feet. ) Here I will go into my computers plan mode, and figure out what surface interval I need to get me close to finishing my next tank, This is where we could do the same thing in the tables, and I do on occasion to keep my skills sharp.
step 4) repeat step 1 until out of tanks.


My post
Case 2) Private Boat.
This is where the divers themselves get to choose a spot and do the dive. This is my favorite type of diving
Step 1) find a location, (usually for us it is between 70 and 130 feet.)
Step 2) Dive till either A) gas or B) NDL runs out.
Step 3) return to boat and fish. and figure out your next location. (Usually for us it is between 30 and 60 feet. ) Here I will go into my tables and then to my computers plan mode, and figure out what surface interval I need to get me close to finishing my next tank, this is where I do both to keep my skills sharp and I have the data I need on my slate in case the PDC goes south.step 4) repeat step 1 until out of tanks.

 

[Puffer Fish]

Valid point, but if I followed that profile my dives would be a lot shorter than they are (OK Nitrox and the nasty computer have more to do with that). However some people are not terribly disposed to get DCS, so who knows, after all these years, I might be one of them. I do know that I have essentially no circulation issues (as in clogged arteries).

puffer fish
(note: I was taught the classic 60 ft = 60 minutes, and 60 ft per minute maximum ascent rate, and no safety stop, should I still be using that today?)

Did you take any hits using it? I never did. I do believe as we age it's probably best to use 30-60. I've always added 2-5 mins to the required time at the last shallow stop, deco not saftey. I do know if my life some how depended on getting to the surface quick during a NDL dive I'd do the 60-60 without a SS without fear,well much anyway.

 

[*dave*]

Yep. And even on much more aggressive dives, I manage to get by without that $1200 AI Cobalt, too!

My point is simple: if a particular student is going to not use tables (especially those divers who already know they will be computer users), and if tables are not a particularly good teaching aid to understanding deco theory, I'd rather spend those 45 minutes which would be dedicated to table teaching to engage in discussion on why dive computers are programmed to indicate varying ascent rates, or why many computers take into account water temperature and workload in their calculations. Now if a student wants instruction in table use, no problem! That student gets tables!

I think we're on the same page, but different paragraphs. Most of my posts relating to instruction are from the context of a mainstream, generic, 8 day course. There is no typical student and there could be a 14yo boy, 68yo man, 23yo man and a 30yo woman in the same class. I'd guess half of them aren't really sure what type of diving they'll ultimately be doing or even what is possible. As the course progresses, students typically start formulating an idea of what it is they would like to do with their new skills and those goals are typically pretty diverse between them. Here, it makes sense to me that I should teach tables and computers. I also instruct for a shop that is running very lean on rental computers available for classes.

In a private course, I spend much more time figuring out what that student is likely to do in the future. If I don't see tables in that future, I agree with you about time being better spent elsewhere.

I also agree with your observations on the degradation of the student's ability to effectively use the tables being an issue. I've also noticed infrequent divers having issues processing the info their computers were presenting and confusion over the operation. I've had questions on boats from divers about 6 yo computer operation. They've had it for 6 years and still can't remember how to set PO2, for instance.

None of this is to say I think one or the other is a better solution. I feel each has its own advantages over the other and students should understand the options in order to make an informed decision as to what best fits their diving.

 

[Kingpatzer]

Well good luck with that. . . . I plan my dives with the US Navy air tables modified by me for me. . . .

Just last week someone offered the use of their software to plan my dives for me. Thanks but no thanks. I'll do it myself.

So, using someone else's computer to print out your tables for you to modify is ok, but using your own computer to print out your tables is not.

Care to explain the logic of that?

 

[Quero]

I think we're on the same page, but different paragraphs. Most of my posts relating to instruction are from the context of a mainstream, generic, 8 day course. There is no typical student and ... I'd guess half of them aren't really sure what type of diving they'll ultimately be doing or even what is possible. As the course progresses, students typically start formulating an idea of what it is they would like to do with their new skills and those goals are typically pretty diverse between them. Here, it makes sense to me that I should teach tables and computers. I also instruct for a shop that is running very lean on rental computers available for classes.

In a private course, I spend much more time figuring out what that student is likely to do in the future. If I don't see tables in that future, I agree with you about time being better spent elsewhere.

I'm sure you're right. Our contexts do color what we "see" ourselves doing. In contrast to you, I teach only private courses, and as such I believe it's my responsibility to help students explore options for they kinds of diving they envision themselves doing. My courses aren't as cheap as the typical group classes around here, and I do include a dive computer as part of the standard gear rental package that's bundled in the course fee, (together with books, cert fees, and boat charters). I am easily able to tailor courses to students' needs. The ones who zip through the academics may need more time and hand-holding in the pool, and the ones who are fish in the water may need a lot of spiraling of information presented in a variety of ways in the classroom sessions before it "sticks." (I am also also able to vary the sequence in which the information is presented through different media depending on individual learning styles.) We always have time for table instruction--it's never a question of running out of time--but I do think that students get saturated with a lot of new information (or new applications of information they've learned elsewhere), and that they can become overloaded quite easily. But yeah, if I had group classes made up of rather heterogeneous learner-types, as you do, I'd probably stick to an approach like yours.

 

[Blackwood]

So, using someone else's computer to print out your tables for you to modify is ok, but using your own computer to print out your tables is not.

Care to explain the logic of that?

I don't think he's saying modifying Vplanner (for example) has less merit than modifying Navy tables.

He has modified the navy tables after years of personal use and feedback. Printing from software would be like starting at square one.

But yah, the post was contextually obtuse.