Overheard an Interesting Conversation at the LDS

[jmorriss]

While looking for some beefy Kevlar gloves at one of the North GA Dive shops I overhead the owner explaining to a prospective OW student that they no longer teach the tables but exclusively use the calculator. Maybe its my educational background (engineer), but my opinion would tend to be that if you can't figure out the table, you shouldn't be diving. Its waterproof, the batteries don't run out and has been the standard for years. While I understand that some people don't pick it up as fast as others and that the eRDP can assist in teaching my point remains-learn how to use the table. I just recently got my first computer (n2ition, can't wait to break it in in Panama City for the 4th :eyebrow: ) I dutitifully brought my tables along on my first 32 dives and tracked my progress on them. It just seems along the lines of some other concerns on here that the agencies may be dumbing down the OW classes. I'd really like to see some comments from instructors on this one.

[gypsyjim]

:shocked2: I am not an instructor, but it seems that learning how to use the tables is part of learning and understanding the processes your body is going threw at depth and over time. It's difficult enough for a new diver to grasp things like residual nitrogen, etc without allowing the student to rely completely of electronic technology to keep them safe. :shakehead:

[alewar]

We can also stop teaching how to do simple arithmetic operations at school, after all children can use a calculator...

[Riger]

Except for EANx training, I have never used tables after OW training.

I am absolutely pro-computer, however, IMO there is nothing that can provide a solid understanding of NDL's like mastering tables.

I think that removal of that aspect of training does 2 (bad) things; (1) it increases the risk of reduced comprehension of NDL's and (2) it forces students to buy computers or electronic tables in order to dive post certification. I have never used the e-planner, so I am not sure if it can be used without a basic understanding of the tables.

I sense a commercial motivation (Sale of Computer or e-planner)......

Best Regards
Richard

[tstormdiver]

I am absolutely pro-computer, however, IMO there is nothing that can provide a solid understanding of NDL's like mastering tables.

I think that removal of that aspect of training does 2 (bad) things; (1) it increases the risk of reduced comprehension of NDL's and (2) it forces students to buy computers or electronic tables in order to dive post certification. I have never used the e-planner, so I am not sure if it can be used without a basic understanding of the tables.

I sense a commercial motivation (Sale of Computer or e-planner)......

Best Regards
Richard

I agree. Our shop still teaches tables but advocates the use of computers with the understanding that tables can be ultra conservative, thus cutting bottom time. It does help the student to understand better the concept of NDL's & also gives them an idea of how the computer tracks your NDL's.

[jmorriss]

Except for EANx training, I have never used tables after OW training.

I am absolutely pro-computer, however, IMO there is nothing that can provide a solid understanding of NDL's like mastering tables.

I think that removal of that aspect of training does 2 (bad) things; (1) it increases the risk of reduced comprehension of NDL's and (2) it forces students to buy computers or electronic tables in order to dive post certification. I have never used the e-planner, so I am not sure if it can be used without a basic understanding of the tables.

I sense a commercial motivation (Sale of Computer or e-planner)......

Best Regards
Richard

IIRC the eRDP is an extra $25 in the LDS's pocket.

[Rick Inman]

This has been talked about here on SB a LOT. Our own NetDoc (board owner) is a computer-no-tables guy. They always use the slide ruler analogy.

I'm in favor of knowing the tables, understanding how to use them and what they are telling us. Just being able to follow your finger across, turn the card over and let it tell you how long you can dive at a depth on the second dive isn't enough. I think divers should know what they are looking at and why. Applying the concept with understanding to your diving is power. It makes thinking through decisions possible, making a safer diver. I think it's insulting to think that people are too stupid to get it. Could it possibly be that training it is difficult, and that rather then becoming good at teaching, some people would rather just cut the material?

[jmorriss]

I agree. Our shop still teaches tables but advocates the use of computers with the understanding that tables can be ultra conservative, thus cutting bottom time. It does help the student to understand better the concept of NDL's & also gives them an idea of how the computer tracks your NDL's.

I am not evening talking about a dive computer-all that thing is a calculator that replicates the tables on the surface-it may have the multi level stuff built into the computer but its still probably more conservative then a real dive computer. Dive computers are awesome IMHO but unless you have the tables to back it up you could have a very expensive and very boring boat ride on the day your battery takes a dump.

[jmorriss]

This has been talked about here on SB a LOT. Our own NetDoc (board owner) is a computer-no-tables guy. They always use the slide ruler analogy.

I'm in favor of knowing the tables, understanding how to use them and what they are telling us. Just being able to follow your finger across, turn the card over and let it tell you how long you can dive at a depth on the second dive isn't enough. I think divers should know what they are looking at and why. Applying the concept with understanding to your diving is power. It makes thinking through decisions possible, making a safer diver. I think it's insulting to think that people are too stupid to get it. Could it possibly be that training it is difficult, and that rather then becoming go at teaching, some people would rather just cut the material?

I agree 100%. The tables aren't rocket science-its arguably easier then doing your own taxes by hand :rofl3: It would be foolish for any dry behind the ears newbie to jump in the water with something attached to their wrist or console without understanding the concepts behind the basics- dive computer theory is pretty advanced IMHO, but in laymen's terms the understanding should be passed down to any level of rec diver. I have borrowed the GF's computer on a few dives that I went on without her :D and still tracked with tables-for all the good it did once I was off them, but nonetheless. Would it be too harsh to say that if you can't learn the tables GTFO? If it were my liability on the line I would want to make sure I had all my ducks in a row. I am a civil engineer by profession-if I were to design a bridge solely in a computer program without ever touching pencil to paper I would be in a world of trouble should god forbid anything ever happen-that being said on stuff like that I do a simpler calculation to check a controlling case or something to make sure my answers are reasonable and THEN have someone else look at the thing to make sure I didn't make the same stupid mistake in two different ways. This eRDP thing just seems to be another example of people looking for the easy way out of things w/o fully understanding the consequences.

[Teamcasa]

I overhead the owner explaining to a prospective OW student that they no longer teach the tables but exclusively use the calculator.

It just seems along the lines of some other concerns on here that the agencies may be dumbing down the OW classes. I'd really like to see some comments from instructors on this one.

The dumbing down is one thing, teaching how to read and understand the tables vs computers is another.

Most recreational divers use their computers more than the tables but that does not mean they were not taught what nitrogen loading is and how to use the tables.

The problem I sometimes see is new divers that don't use the tables AND do not know how to operate and read their computers.

[jmorriss]

The dumbing down is one thing, teaching how to read and understand the tables vs computers is another.

Most recreational divers use their computers more than the tables but that does not mean they were not taught what nitrogen loading is and how to use the tables.

The problem I sometimes see is new divers that don't use the tables AND do not know how to operate and read their computers.

This isn't a computer vs. tables debate-its about the substitution of the dive tables with a calculator. Computers are cool :dork2:

[RoatanMan]

I am not evening talking about a dive computer-all that thing is a calculator that replicates the tables on the surface-it may have the multi level stuff built into the computer ......

It is a way for training agencies to slowly step back from the tables, so in that light, it further validates your stance of: "knowledge is good" (Faber College)

For the vast majority of newly trained divers, they're the people who are heading to paradise and embarking on a weeklong program of repetetive dives.

The tables will indeed have their application for the guys that do their 5 in a weekend, but the use of tables for that more common critter- the week long warm-water pretty fish diver is very limited.

People who want to get certified (the vast majority) want to prepare for their big weeklong multi dive trip. They do not want to screw around with paper tables when a computer (something they are well used to), will do the job more efficiently.

This typical new diver is why e-Learning is the future. PADI and others see that LDS will be less accessible and they have put all their marketing efforts into the obvious future: expanding the "open water referral" logic to "confined/open water referral" in paradise model.

If this new diver headed to Cayman and got certified by Thursday, if he was working tables, it would be telling him that by the end of the week- he ought to be quite dead.

On a week in paradise of repetitive diving, if you are running the tables, you're dead by Tuesday. Computers let you live on to tell tales of the briny deep around the water cooler.

It's a marketing move, brought about by the needs of the bulk of new incoming divers. Learn the tables if they are useful in your type of diving, but for the vast majority of warm water pretty fish divers, they will be a thing of the past.

[Riger]

This isn't a computer vs. tables debate-its about the substitution of the dive tables with a calculator. Computers are cool :dork2:

I agree that computers are cool, however in my case, the moment I was able to correctly plan 3 repetitive dives on the tables, I got more than the correct answer, I understood the impact of nitrogen loading with respect to depth and time.

Best Regards
Richard

[sabbath999]

We took our Nitrox training at a different LDS than where we learned our OW.

Our OW shop is very old fashioned, and the classes are all taught by people who have been cave divers for 20+ years... very conservative folks. We did tables in OW, and nothing but tables.

We took our Nitrox class with a shop in a different city, and the instructor pulled out a table and said to the class "This is something you all have never used before...", assuming that we had all graduated from that shop's OW program... they teach calculator only.

Not surprisingly, we had a lot less trouble learning the Nitrox tables than the rest of the class.

I don't use the tables, at all... but I carry them with me "just in case"

[jmorriss]

I agree that computers are cool, however in my case, the moment I was able to correctly plan 3 repetitive dives on the tables, I got more than the correct answer, I understood the impact of nitrogen loading with respect to depth and time.

Best Regards
Richard

As did I, I planned two 4 tank boat dives and a long day of 5 dives @ Ginnie on tables.

[awap]

Do any of today's dive computers support planning for anything more than the next dive baseds on the current surface interval?

[jmorriss]

Do any of today's dive computers support planning for anything more than the next dive?

You mean as if "if I do this dive to x feet for y time, what can I do after that"?

My zeagle won't.

[sabbath999]

Do any of today's dive computers support planning for anything more than the next dive baseds on the current surface interval?

Yes, but only for dives done with split fins :)

Alas, my Scubapro wont... (it is Jet Fin oriented)

[gr8fuldiverNC]

Do any of today's dive computers support planning for anything more than the next dive baseds on the current surface interval?

kind of; every dive computer ive ever used (and thats over 20 models), will allow you to add surface interval on top of current surface interval when planning your next dive. however, i dont think any of them will allow for planning multiple dives ahead of time, that is you can only plan the next dive.

[rstofer]

Another failing of the eRDP: it doesn't provide RNT. But it will let you plan a long sequence of dives.

The eRDP isn't waterproof so it can't be used to plan on-the-go. In the early days (circa '88), I would write the Adjusted NDLs on a slate for all probable depths. I could just look at my bottom timer, depth gauge and slate to figure out when it was time to surface. That, and it's tough to get into trouble with an Al 80. It's possible, but you have to work at it.

The eRDP-ML will work multi-level dives. I haven't used that feature but it seems more useful after the dive than before. Somehow, I never knew how deep I would be going or what the profile would look like. I guess I just jumped in, swam down and around and came back up.

Like several folks above, I like the way the tables keep you involved with your nitrogen loading. I'm not a fan of the eRDP and I like computers only slightly more. Sure, I have a computer. But I bought it to keep track of the Nitrox thing. Nitrox seemed to add more complications than I was willing to solve by hand. I just got lazy...

Richard

[awap]

The ones I have used (EDI, IQ-300, and Oceanic Data+) don't even allow me to vary (add) SI. Tables (and experience) are more useful for multiple dive planning.

[djanni]

We learned the tables but haven't looked at them since the written test. We bought computers right from the start and that's all we've used since. I doubt I could read tables anymore. Change that, I'm sure I couldn't.

I'm glad we learned them. It put emphysis on the importance of following the time/depth guidelines.

We got our Nitrox Cert through SSI and while we went over the Nitrox tables it wasn't a detailed review.

We're recreational divers and if equipped with a computer, I think the tables are useless. I can understand why, on some technical dives, divers would want to use tables and it's probably a good idea.

[Alex Dailey]

Up until my last set of dives, I've used the dive tables exclusively. True, they are conservative time-wise in regards to bottom time with being a square profile, but knowing how to use them and not having to worry about electronic failure is comforting.

That said, using a computer this last set of dives was very nice. Bottom time was increased quite a bit, and having the computer to keep track of surface intervals was nice (even though I kept track as well, never quite trust electronics entirely). I do miss not having the end of dive letter group, and don't quite know if the computer takes into account if the water is cold or you are exerting yourself more (which moves you up a letter on the NAUI dive tables). Computers can also store your dives, but I keep a log book - never know if computer fails and then you loose all dives (which has happened to people I've talked to). Plus, I like being able to flip through all my past dives and see how much weight I used, what I saw, remarks regarding the dive, etc.

I'm of a mixed opinion...I like using the dive tables, but using a computer does allow for more dive time. It is another piece of equipment to worry about, and if it fails halfway into your dive and you aren't familiar with/don't know the dive tables, then what do you do?

I had a conversation about this with a coworker, who stated that he hadn't used the tables in years and didn't think you needed them. Quite a few other people I've asked have a similar opinion. I tend to view it with the same philosophy as my instructor - never use equipment to overcome a lack of skill or inability to perform a skill. If you want to use a computer - fine. Want to use a dive table - fine. Just make sure you know how to use the basics before moving on to something else.

[jmorriss]

... and don't quite know if the computer takes into account if the water is cold or you are exerting yourself more (which moves you up a letter on the NAUI dive tables).


Most computers have an adjustable safety factor that you can increase.


I had a conversation about this with a coworker, who stated that he hadn't used the tables in years and didn't think you needed them. Quite a few other people I've asked have a similar opinion. I tend to view it with the same philosophy as my instructor - never use equipment to overcome a lack of skill or inability to perform a skill. If you want to use a computer - fine. Want to use a dive table - fine. Just make sure you know how to use the basics before moving on to something else.

My point exactly.

[TMHeimer]

I'm currently taking the DM course and the new eRDPml is required (PADI) in place of the outdated and apparently difficult to use "Wheel" (though their books still refer to The Wheel). You can calculate multi-level dives with this new gadget. It would seem you wouldn't need to be able to use the tables now as long as your eRDPml is working. I do agree, though, that knowledge of the RDP certainly gives you visual help in understanding decompression models. I do one problem every day with either the RDP or Nitrox tables. Takes about a minute. Interestingly, when I took the Nitrox course 3 years ago, the instructor had to spend a lot of wasted time re-explaining the AIR RDP to 2 in the class who couldn't use it.....

[Slonda828]

There's always three points I make on any charter with new divers:

1.) If your computer breaks, you have to dive tables and you've already paid. If you cannot use tables, you just threw 150 bucks in the ocean to get seasick and sunburned. Plus, you feel like a waterhead because you cannot comprehend something simple, like dive tables.

2.) Dive tables are not "ultra-conservative" on square profile dives. I've dove tables and still used my N2ition on wreck dives, and there is not a marked difference. The models are the models. If you are using the Buhlman model, then it doesn't matter if the computer tracks your NDL or you do. The only reason the computer gives you more bottom time is because it credits you for shallow time (we know this). So if you are diving to one set depth and then returning, there is not a great difference in time. The PADI RDP for example, uses the 6 hour compartment as the controlling compartment. This puts it right up there with many dive computers.

3.) I tutor kids professionally in math who only learned how to use calculators instead of doing it with a pencil. Most of them do math on a 5th grade level, and they are usually old enough to drive. There is something to be said for learning how to do something yourself without the help of a computer to think for you. Waging wars, love making, and dancing are all examples of this. Ask your kid to convert a fraction to a decimal with just a pencil tonight and see what I mean.

:D

[jmorriss]

3.) I tutor kids professionally in math who only learned how to use calculators instead of doing it with a pencil. Most of them do math on a 5th grade level, and they are usually old enough to drive. There is something to be said for learning how to do something yourself without the help of a computer to think for you. Waging wars, love making, and dancing are all examples of this.

:D

My argument would be that I still can't do Calc 2 + without my calculator :D

[fnfalman]

I have TWO dive computers and I still pack my tables with me whenever I go diving. One set (RDP, EANX 32, EANX 36, Air Equivalence, altitude adjustment) stays with my log book and an identical set stays with my save-a-dive-kit.

[jmorriss]

I have TWO dive computers and I still pack my tables with me whenever I go diving. One set (RDP, EANX 32, EANX 36, Air Equivalence, altitude adjustment) stays with my log book and an identical set stays with my save-a-dive-kit.

My set sits topside with my logbook and I will make a note of the NDL for the site depths on my slate.

[Teamcasa]

Most computers have an adjustable safety factor that you can increase.

This isn't a computer vs. tables debate-its about the substitution of the dive tables with a calculator. Computers are cool :dork2:

Which calculator would that be?

[jmorriss]

Which calculator would that be?

http://4.bp.blogspot.com/_NvN8AWYQavg/SHP10l7MvEI/AAAAAAAAApk/38QclfJpjEY/s400/eRDPMLJly08_10.jpg

PADI Instructor News: Introducing the eRDPML (http://www.padiinstructorinfo.com/2008/07/introducing-erdpml.html)

[Slonda828]

My argument would be that I still can't do Calc 2 + without my calculator :D

Very true, but you have to admit that using a dive table is not equal to the complexity of performing complicated levels of math with just a pencil.:coffee:

As an aside, the ERDPml is just the wheel and RDP's love child. If you already know how to use either both, or either, then it is nothing earth-shattering. I used it for my DM exams, but that was only because the wheel that the academy had was the size of a truck hood. Also, it's not waterproof. We found that out the hard way...

[jmorriss]

Very true, but you have to admit that using a dive table is not equal to the complexity of performing complicated levels of math with just a pencil.:coffee:

Heck no :cool2:

[Slonda828]

Heck no :cool2:

I never laugh out loud when I am alone, but you just got a laugh out of me. You're a pretty cool customer man! :rofl3:

[jmorriss]

I never laugh out loud when I am alone, but you just got a laugh out of me. You're a pretty cool customer man! :rofl3:

Gotta do something to make work go by faster :D

Now if I could only get my company to pay for commercial training....:eyebrow:

[jwc3]

I overhead the owner explaining to a prospective OW student that they no longer teach the tables but exclusively use the calculator.

This is not a debate about tables versus computers. As with most things, this is really about money. By requiring all students to buy a computer, the LDS is trying to increase their equipment sales (and thus their profit).

[T2medic]

Everyone is looking to make things easier! I feel that the RDP is completely neccesary in the learning process. If that means spending 2-3 hours making sure everyone in your class has a perfect understanding then so be it. I have personally spent this much time because I believe in it. If your on a trip and batteries go bad, or your eRDPml gets dropped in the water, what are you going to do? My students know the RDP both forward and backwards. We go all the way through the O/W class using nothing but the RDP for calcs. We don't even order the crew paks with the eRDPml. We do however show the student the eRDPml and thoroughly explain it's use and it's advantages after their last dive while they are filling out their pic cards. It does make calculating indepth dive plans much quicker thereby saving valuable time and it's multilevel abilities are very useful. The AOW multilevel adventure dive should not be the first time a diver gets exposed to calculating ML dives. The wheel is one way, but IMO, the eRDPml does have it's place and is much quicker. I think everyone should carry the RDP, but I also think that everyone should be able to at least see what the eRDPml brings to the tools a diver has at his disposal.

[boulderjohn]

Warning: Far flung analogy to follow.

As far back as the 1700's people were arguing the value of requiring students to learn Latin. Benjamin Franklin weighed in on this argument in his autobiography (which is still one of the most influential books I have ever read). The most common argument for requiring Latin was that it made it easier for students to learn other romance languages, like French. Franklin pointed out that the opposite is also true. If they learned French, they would have an easier time learning Latin later, and if they stopped after one language, they would have someone to talk to.

In general, the argument for teaching concept A because it helps you learn concept B is undercut by the fact that it just might be better to teach concept B in the first place. You have to look at concept A by itself to see if it has a value.

When you teach the tables, you are teaching a mechanical process by which dives can be planned. It is one way of doing it. There are others.

Can a student learn other things as as a side benefit to that process? Nitrogen loading is often mentioned. I am not sure what else might be there. If you want to teach those other things (concept B), it is more efficient to teach them as the primary purpose of a lesson rather than a hoped-for side benefit of teaching something else.

I think nitrogen loading is very important, and so it is stressed in my class from the first academic lesson, which includes Boyle's law (the basic reason we end up with residual nitrogen). My students understand the concept that they have residual nitrogen after a dive long before we talk about the tables. Thus, when we teach the tables, they are learning one way of accounting for that residual nitrogen about which they have already been instructed. If I were to teach the eRDPml instead, they would be learning another way, one that would take much less instructional time that could be devoted to other purposes.

The argument should be on the value of one planning process against the other for that reason alone. Any other attached learning can still be taught, and probably more efficiently if made the primary goal.

[ivobj]

You can use the calculator to check your conclusions, but learning the tables is fundamental, rock solid, calculator can fail, not the tables. IMO not teaching tables in an OW course is unthinkable.

[Teamcasa]

Which calculator would that be?

http://4.bp.blogspot.com/_NvN8AWYQavg/SHP10l7MvEI/AAAAAAAAApk/38QclfJpjEY/s400/eRDPMLJly08_10.jpg

PADI Instructor News: Introducing the eRDPML (http://www.padiinstructorinfo.com/2008/07/introducing-erdpml.html)

I like it John.

Why are divers taught about Nitrogen Loading in the first place? Because it is a very important effect that all divers must understand and consider.

How is it explained in class? Most are given tests and knowledge reviews along with instruction on how to use the tables, be they hand cards or eRDP's while some get instruction on their computers as well.
The method is not as important as the information the student leaves with.

I was taught to use a slide rule (back before time began), then HP came out with the nifty HP-65. Out went the slide rule. Do I still understand calculus and trig, I hope so. I also used an Vemco Vtrack now AutoCad and Solidworks are the standard. Can I still design a component, I hope so.

The point is I could care less how or what method the instructor uses to teach about Nitrogen Loading. All I do care about is that the student learns and understands how it will affect their diving profile. I also care that they know and understand how to use whatever tool they employ to plan their dives.

[RoatanMan]

http://4.bp.blogspot.com/_NvN8AWYQavg/SHP10l7MvEI/AAAAAAAAApk/38QclfJpjEY/s400/eRDPMLJly08_10.jpg

I still have a small supply of custom fitted Ikelite U/W Housings available.

[jmorriss]

I still have a small supply of custom fitted Ikelite U/W Housings available.

:rofl3:

[Teamcasa]

I still have a small supply of custom fitted Ikelite U/W Housings available.

Sweet!;):rofl3:

[JTH2711]

I plan to do cert in a few months. I want to know the tables. I trust my math better than the computer's. Also a computer is only a tool and sometimes tools do fail. My Multimeter at work has to be calibrated twice a year. If I have stick my hand in a 277v cabinet, I am going trust myself to turn off the breaker and then what the meter says. Not vice versa

[Slonda828]

I plan to do cert in a few months. I want to know the tables. I trust my math better than the computer's. Also a computer is only a tool and sometimes tools do fail. My Multimeter at work has to be calibrated twice a year. If I have stick my hand in a 277v cabinet, I am going trust myself to turn off the breaker and then what the meter says. Not vice versa

That's a good way to look at it. It sounds like you are fully prepared to be responsible for yourself. BTW, I trusted a multimeter once when we were working on a P-3C Orion aircraft's main load center. I woke up in the aid station with a corpsman checking the soles of my feet :D

It's always good to know what to do when the equipment does not work.

[boulderjohn]

I plan to do cert in a few months. I want to know the tables. I trust my math better than the computer's. Also a computer is only a tool and sometimes tools do fail. My Multimeter at work has to be calibrated twice a year. If I have stick my hand in a 277v cabinet, I am going trust myself to turn off the breaker and then what the meter says. Not vice versa

It really isn't as simple as that.

When you learn your tables, you may be surprised to learn that there is very little math involved. What you learn is a multi-step process that many people find very confusing. In planning a single dive, there is no math whatsoever. In planning multiple dives, one step requires very basic addition. That's it.

I do a pretty good job teaching the tables, if the fact that I rarely have a student get a table problem wrong on the final exam is an indication. I do have students who struggle to learn the tables, but they can all add just fine. They struggle to learn the sequence of the many steps required. I would say 1/3 of the mistakes students do make on the exams come from misreading the very fine print on the tables and picking the answer from the wrong column.

The "calculator" version pretty much walks students through the steps so that they are never confused by that problem, and it keeps them from making a mistake by reading from the wrong column. It does do that one addition step for them.

Computers really serve a different purpose--they are not just doing the math calculations for you.

You will learn this in your class, but I will give you a preview.

With the tables, you have to assume that your deepest depth is the depth at which you spent your entire dive. (Yes, it is possible to do multiple depths, but that is a very advanced skill that is not taught in the classes and is rarely done.) If you do a dive to 100 feet for 2 minutes to look at some garden eels and then ascend to 50 feet for some of the dive and then survey the top of the reef at 20 feet for the remainder, you must still plan as if you spent the entire dive at 100 feet. With the PADI tables, you have a maximum time of 20 minutes for all phases that dive combined. You might get on the boat with half your air still in the tank.

If you use the PADI eRDPml to plan that dive, you can enter time at 100 feet, 50 feet, and 20 feet, and you will get much more than 20 minutes total time on that dive, because it essentially (and over simplistically) treats it as 3 consecutive dives. Like the basic table, you have to plan the time at each depth before you dive, and then follow that plan to be sure of staying within limits.

If you are planning a dive using a computer's planning function, you enter your depth and it tells you what you maximum time at that depth will be if you spend your entire time there. But that is not why most people use them. Unlike the tables and the eRDPml, you take the computer with you, and it constantly adjusts and recalculates based on your actual changing depths. You could easily end up doing an 80 minute dive with a maximum depth of 100 feet, assuming you do not spend too much time at the greater depths.

[Coldwater_Canuck]

I'm absolutely for a computer and feel that they should be standard diving equipment (helps in a number of ways).

However, one area the tables are much better is making rough dive plans. Weeks ahead of a dive you can figure out rough surface intervals, what depths you should dive to, if you require Nitrox, etc. In fact, just yesterday I took them out to make sure that I'd be able to fit all the dives I wanted into the time I wanted.

Computers have the advantage of giving specifics, tables are great for giving a general idea. I'll dive on my computer, but the tables are really useful to know. I also feel just teaching the computer without the underlying theory isn't the best way to understand it.

[jmorriss]

However, one area the tables are much better is making rough dive plans. Weeks ahead of a dive you can figure out rough surface intervals, what depths you should dive to, if you require Nitrox, etc. In fact, just yesterday I took them out to make sure that I'd be able to fit all the dives I wanted into the time I wanted.



I usually jot down prospective dive plans on a 4x8' marker board. Speaking of which I should get started for our next adventure...

[JTH2711]

My point is is that I think it is a good skill to have in your back pocket. I want to be a self sufficient and responsible diver. Mistakes in water could easily get me or someone else hurt. I just feel it is another tool to have in the tool box. Most computers I see will be out of my budget for a while. That being said I am perfectly fine with adjusting to the learning curve at a safe depth until I have the confidence to go to deeper. Thank you for the tutorial on tables I appreciate it.

[roturner]

:shocked2: I am not an instructor, but it seems that learning how to use the tables is part of learning and understanding the processes your body is going threw at depth and over time. It's difficult enough for a new diver to grasp things like residual nitrogen, etc without allowing the student to rely completely of electronic technology to keep them safe. :shakehead:

There's a big discussion about this in the I2I forum right now. It would appear that PADI is going to change standards to make teaching tables optional.

To summarise how I understand the discussion there seems to be a few main points.

1) tables have always been an integral way of teaching diving and some instructors will not let go of that. Other instructors see the reality on the ground and think we should be letting go. Making this change will take time and it will cause some instructors to need to find new ways of explaining things like dive planning and deco theory so I personally expect it will be a process analogous to removing wallpaper. (ie. a gradual shift as opposed to a sudden one)

2) adopting computers as mandatory dive gear pushes an extra cost onto the student but the flip side (dropping tables) addresses the reality that most divers use computers anyway.

In short, the instructors on the board have mixed feelings and mixed opinions about it.

Just to address the post I quoted, gypsyjim, it's a fallacy to think that you learn deco theory just by learning how to use tables--although admittedly many instructors use the tables as a framework to hang it on--and an even bigger fallacy to assume that if you *don't* learn tables that you will miss out on this. In fact, I personally think that if you aren't teaching tables that you may find more effective ways to get students to understand deco theory. In other words, this is, from my point of view, as much an "opportunity" as a "complication".

R..

[RonMurray]

Key quote "the owner of the dive shop was explaining..."

The guy has an interest in selling computers. I don't think any of the certifying agencies have stopped requiring a working knowledge of dive tables. But the shop owner was (understandably) both allaying the fears of the prospective student and greasing the skids for the sale of a nice air integrated computer.

Can you blame him?

[jmorriss]

Key quote "the owner of the dive shop was explaining..."

The guy has an interest in selling computers. I don't think any of the certifying agencies have stopped requiring a working knowledge of dive tables. But the shop owner was (understandably) both allaying the fears of the prospective student and greasing the skids for the sale of a nice air integrated computer.

Can you blame him?

Not talking about computers, simply talking about the Electronic recretational dive planner.

From what I hear out of PADI instructors this is the way PADI is headed.

[Blackwood]

I agree that computers are cool, however in my case, the moment I was able to correctly plan 3 repetitive dives on the tables, I got more than the correct answer, I understood the impact of nitrogen loading with respect to depth and time.

Best Regards
Richard

Similarly, if you merely watch your computer's "remaining NDL" display throughout a dive, you will understand the impact of depth and time on nitrogen loading. In fact, since the NDL display will change in real time, your understanding will (potentially) be better than that gained by running through square dives on a table. For example, how with a standard table will you demonstrate the effect ascending or descending has on your NDL?



Very true, but you have to admit that using a dive table is not equal to the complexity of performing complicated levels of math with just a pencil.:coffee:

The algorithms which spit out the numbers on the tables are rather complicated.

Personally, I find the suggestion that "you should learn tables to that you understand basic decompression theory" to be fallacious. 99.9% of divers who have learned to slide their fingers around on a piece of plastic have no understanding of the underlying principles. They merely know how to do something even more mundane than tying their shoes.


If your on a trip and batteries go bad, or your eRDPml gets dropped in the water, what are you going to do?

Go diving. 120-Depth=MBT.

[Sinbad the Diver]

I have never used tables, I was taught on a computer and never looked back. I understand the concept of how they are used, but I prefer to use my computer because it gives me updated info as I go along based on what has happened vs what I thought would happen. I can plan repetitive dives based on what I did on my dive (the whole dive, not just the deepest part of the dive). As someone mentioned earlier, with my computer I am able to see the impact on NDL as I go deeper and that was more valuable to me than seeing the numbers on a table on the surface (note, I said to me, everyone is different).

The only downside that I can see is that if the battery or the computer dies, my dive is over and I may miss a couple if I can't get it replaced.

Once I move beyond recreational, no deco dives, I'm sure I will want/need to increase my specific knowledge of tables and nitrogen loading and fizzzzzziology. Would it hurt me to have that knowledge now, no...but I don't see that having makes me any safer than not having it. I began diving not to be a great diver, but to see things I couldn't see without it.

That being said, I don't think that there is anything wrong with using tables, if that's what you know and what you prefer. Some people like stick shifts, some like automatics....to each his own.

[Sinbad the Diver]

Not talking about computers, simply talking about the Electronic recretational dive planner.

From what I hear out of PADI instructors this is the way PADI is headed.

SDI has relegated tables to the back of the book. They teach that they exist, give a quick tutorial on how they work and then explain that a computer algorithms use that information. That's the end of the table discussion with an SDI cert.

[Wrecks30]

I was just certified in May, and we were taught the tables, never even touched the calculator. I almost failed them dang tables at first...lol

[Slonda828]

Personally, I find the suggestion that "you should learn tables to that you understand basic decompression theory" to be fallacious. 99.9% of divers who have learned to slide their fingers around on a piece of plastic have no understanding of the underlying principles. They merely know how to do something even more mundane than tying their shoes.


I would agree, I never once said that you understand decompression theory if you learn tables. My point was that people who cannot dive when their computer's battery dies (or it floods, as I've seen recently) should either learn how to use tables or buy lots of sun block and hope that they do not get seasick.

[Slonda828]

SDI has relegated tables to the back of the book. They teach that they exist, give a quick tutorial on how they work and then explain that a computer algorithms use that information. That's the end of the table discussion with an SDI cert.

I'm not an SDI guy, so I'm genuinely curious. Is it implied that you should learn tables on your own, or do you just hope that you never break your computer, or that it never has a dead battery or bad o-ring? Do they encourage you to learn them as a backup, or are you just supposed to have blind faith in your computer?

[Blackwood]

I would agree, I never once said that you understand decompression theory if you learn tables. My point was that people who cannot dive when their computer's battery dies (or it floods, as I've seen recently) should either learn how to use tables or buy lots of sun block and hope that they do not get seasick.

That comment was directed towards a general idea found throughout this thread (and the boards), not specifically your post I quoted.

eg

"but it seems that learning how to use the tables is part of learning and understanding the processes your body is going threw at depth and over time"

"It would be foolish for any dry behind the ears newbie to jump in the water with something attached to their wrist or console without understanding the concepts behind the basics"

"I also feel just teaching the computer without the underlying theory isn't the best way to understand it."



The widely-accepted implication (one that I'm attempting to refute) is that learning how to use a table is the same as understanding the fundamental concepts and theories at its base.



I'd further question why blind faith in a computer is 'bad' whereas blind faith in a table is perfectly acceptable.

[Slonda828]

That comment was directed towards a general idea found throughout this thread (and the boards), not specifically your post I quoted.

eg

"but it seems that learning how to use the tables is part of learning and understanding the processes your body is going threw at depth and over time"

"It would be foolish for any dry behind the ears newbie to jump in the water with something attached to their wrist or console without understanding the concepts behind the basics"

"I also feel just teaching the computer without the underlying theory isn't the best way to understand it."



The widely-accepted implication (one that I'm attempting to refute) is that learning how to use a table is the same as understanding the fundamental concepts and theories at its base.



I'd further question why blind faith in a computer is 'bad' whereas blind faith in a table is perfectly acceptable.



I dig man, I did not realize that you were not talking "to" me since you quoted me. As for the whole blind faith thing, I guess I can sum up my opinions like this:

-With tables, the only thing you can screw up is reading them. Everything is right there in plain English on waterproof plastic.

-With a computer, you can mess up lots of settings like (on mine at least) altitude, personal fitness level, % of o2 for current mix, salinity of the water, whether you want a deep stop or a safety stop, etc. I'm not saying that computers are bad, I have a few, and I use them on all non-vintage dives. What I am saying is you should have a general idea of your NDL for the depth that you are going to dive, and tables are an easy way to do that for lots of recreational divers. If you use Vplanner or some other such software, then "good on ya". Most people do not use software though (myself included), and tables fit in the back of your log book in case you get ambushed by Murphy. The group of which I am a part of still trains all new divers to use both tables and computers, so that they can use either. We have had success with this method.

That is pretty much how I feel. If I'm woefully ignorant or missing something here, I'd love to hear about it, as you always have intelligent and well-thought out comments.

[Thalassamania]

Computer or tables, I really don't give a damn, both work. Tables are a series of snapshots of a computer, computers are a cartoon of a set of tables ... same, same. The problem is that many instructors now seem to feel that all they should to teach a diver about nitrogen absorption and release is that hey should keep a positive number on a display ... and that I think is wrong. How is a diver going to make an informed consent to subject himself or herself to a hyperbaric environment if that is all the information that they really have at their disposal?

What does it matter if someone learns to decipher the 20 odd datum displayed on a computer or to move from column to row to table to table? It's the same damn thing. The critical question with respect to teaching diving is, "was adequate background provided, and mastered, so that the student actually understands how to use the table or computer." If that was, in fact, done, then a student should be able to use either without a whole lot of trouble.

In my mind the real point is that a student needs to be able to explain the underlying principles of decompression theory. They need to know what an "M-Value" and a Surfacing Ratio is. If they don't, does it really matter if they use a set of tables or a dive computer ... they really do not know what they are doing or why they are doing it, they are just off on yet another "trust me dive" and it really does not matter what form the information controlling the dive is expressed in.

I am not satisfied with putting divers who have not read their dive computer's manual into the water. Without having done so they have no real idea of of how to properly interpret and properly respond to anything except the NDL window. I am not satisfied with that, I doubt if a court would be satisfied with that, no training agency should be satisfied with that.

I find that, having provided the basic information, it takes about the same time to get a classroom full of students to be able to use tables for multiple repetitive dives as it takes to completely go over the operation and interpretation of most dive computers.

But don't get me wrong, I am a strong advocate of using dive computers; but I do not see them as just one more way to scrimp on training. That was an eventuality that we warned the recreational community about in no uncertain terms back in 1988 (AAUS Dive COmptuer Workshop PDF) (http://si-pddr.si.edu/dspace/bitstream/10088/2720/1/proceedings_divecomputers.pdf).

[Blackwood]

That is pretty much how I feel...

Thal pretty much summed up what I would have said in his third paragraph above.


In my mind the real point is that a student needs to be able to explain the underlying principles of decompression theory. They need to know what an "M-Value" and a Surfacing Ratio is. If they don't, does it really matter if they use a set of tables or a dive computer [?] ... they really do not know what they are doing or why they are doing it, they are just off on yet another "trust me dive" and it really does not matter what form the information controlling the dive is expressed in."

(Caveat: I'm not hard over on it being crucial that divers understand m-values, etc.)

[mikemath]

I was taught on the RDP table and am very adept at using it. Now that the Wheel RDP is being phased out, PADI's only endorsed multi-level dive planner is the eRDPml calculator. I learned to use it for the multi-level questions in the DiveMaster RDP exam, and I have to say, it's a great tool and I would recommend it for new students with no hesitation whatsoever.

Two points to address some confusion earlier in the thread about the eRDP or eRDPml:

It is not a dive computer. It is a dive planner. It accepts the same inputs as the RDP (depth, bottom time, and surface interval), and outputs the same information (pressure group, no-decompression limits, minimum surface intervals, and what sort of safety stops are required)
For any given values, it will give you the same output as the table form of the RDP.


For practice while studying for the exams, I ran through problems using both the table and the eRDPml. Despite my experience and familiarity with the table, I was faster with the eRDPml, particularly for more involved calculations like minimum surface interval. I have helped many other divers figure out how and why the table works. The most common problems I've seen in new divers with tables are:

"carry-over" issues, where the user must flip over the table and remember their state. When they're doubting themselves, this is a common step that freaks them out.
RNT+ABT. It's simple addition, but when people are free-handing the table, instead of using a dive profile diagram to fill in numbers, I've seen it bite them frequently.
following the wrong row on the surface interval chart. They're color-alternated, but small enough that if you get distracted, your finger could plausibly be pointing to more than one.


Because the eRDP and eRDPml require only the direct entry of known factors, not the calculation of intermediate steps, I believe the error rate with the eRDP will be less than the table-form RDP. Other posters expressed concern about training students with the eRDP instead of the table. The major concepts that need to be covered are the effect of depth on no-decompression limits, the cumulative effect of nitrogen-loading on multiple dives (RNT), pressure groups, filling out a dive profile diagram, and the effects of surface intervals. All can be discussed theoretically without the use of the table or the eRDP. Either form of the RDP can be used to demonstrate practically using examples of how these concepts come together for particular dives. I think the ability to focus on why dive planning is important instead of how to calculate their dive plan is a great advantage.

[Thalassamania]

(Caveat: I'm not hard over on it being crucial that divers understand m-values, etc.)
I don't mean that the need to have a depth of understanding so as to be able to cut a new set of tables in their head from first principles, after all ... that'd break Billy-Bob's rice bowl.

I want them to understand what they are conceptually, and how they are used to construct a model, and how that model can be represented in many forms such as tables or a computer.

[Teamcasa]

..The point is I could care less how or what method the instructor uses to teach about Nitrogen Loading. All I do care about is that the student learns and understands how it will affect their diving profile. I also care that they know and understand how to use whatever tool they employ to plan their dives.


Computer or tables, I really don't give a damn, both work. Tables are a series of snapshots of a computer, computers are a cartoon of a set of tables ... same, same.
<snip>
But don't get me wrong, I am a strong advocate of using dive computers; but I do not see them as just one more way to scrimp on training.

I agree with Thal, again.;)

[boulderjohn]

I don't mean that the need to have a depth of understanding so as to be able to cut a new set of tables in their head from first principles, after all ... that'd break Billy-Bob's rice bowl.

I want them to understand what they are conceptually, and how they are used to construct a model, and how that model can be represented in many forms such as tables or a computer.

Assuming I understood you perfectly, I agree. As I have said in several forums that are discusing this, I teach the concept in conjunction with Boyle's Law. Once they get that concept, I show how diffusion works, why they on-gas at depth, why they off-gas on ascent, and why they cannot let the gradient get too large. (I do not use the term M-value, and I do not talk about the fact that different tissues have different M-values.) Including the concept of diffusion is very helpful for them to see why this happens.

By the way, this does not take long at all.

[Thalassamania]

Assuming I understood you perfectly, I agree. As I have said in several forums that are discusing this, I teach the concept in conjunction with Boyle's Law. Once they get that concept, I show how diffusion works, why they on-gas at depth, why they off-gas on ascent, and why they cannot let the gradient get too large. (I do not use the term M-value, and I do not talk about the fact that different tissues have different M-values.) Including the concept of diffusion is very helpful for them to see why this happens.

By the way, this does not take long at all.We're eye to eye on this one. It take less time to present the "add on" deco theory stuff than it does to read a Dive Computer manual in its entirety.

[jmorriss]

They need to know what an "M-Value" and a Surfacing Ratio is.



Is this something I can find in the Navy Dive Manual?

[Thalassamania]

Your best source may be some of the AAUS material that is up on will be Gene's Rubicon Foundation site.

[boulderjohn]

We're eye to eye on this one. It take less time to present the "add on" deco theory stuff than it does to read a Dive Computer manual in its entirety.

Much less. And I venture to say I can do it in a manner that is a bit more comprehensible than the average Dive Computer manual.

[Thalassamania]

I have not seen a comprehensible Dive Computer manual since the "Skinny Dipper."

[boulderjohn]

I have not seen a comprehensible Dive Computer manual since the "Skinny Dipper."

There was once a comprehensible dive computer manual? Wow! I would like to have seen it.

This is an example of the value that people with your experience bring to ScubaBoard. I would never have dreamed that this was true.

[RetMTFE]

Just another example of the "dumbing down" of America

1. Kids that can't tie shoe laces......Velcro
2. People that can't tell time looking at a regular clock......Digital
3. People that can't use a compass or read a map......GPS
4. Kids that can't perform simple math calculations.....Calculators allowed in schools

The list gets longer every day

[gypsyjim]

5. People that can't hold a real conversation with another person.....Internet and texting :D

[awap]

Just another example of the "dumbing down" of America

1. Kids that can't tie shoe laces......Velcro
2. People that can't tell time looking at a regular clock......Digital
3. People that can't use a compass or read a map......GPS
4. Kids that can't perform simple math calculations.....Calculators allowed in schools

The list gets longer every day

People who can't work a slide rule....damn those calculators
People who can't load and fire a muzzle loader....modern rifles
people who can't hand crank an automobile....modern cars
people who can't make their own soap....Dove
people who can't make a stone axe....the iron age

Are we dumbing down or changing?

[jmorriss]

People who can't work a slide rule....damn those calculators
People who can't load and fire a muzzle loader....modern rifles
people who can't hand crank an automobile....modern cars
people who can't make their own soap....Dove
people who can't make a stone axe....the iron age

Are we dumbing down or changing?

Its a little different-when you make a mistake on a math test b/c you had to do it by hand, your not going to die of the bends. At least I would hope not.

Think about it this way-how many people nowadays can make change? Tell me you haven't gotten a weird look when you hand the drive through person a penny and some bills :confused:

[roturner]

Well....

This is the generation gap. Every generation has one.

My grandparents wrote letters. My parents sent cards, I write emails

My grandparents shoveled coal into their furnace. My parents got theirs connected to gas. I don't even know what a coal furnace looks like. :)

My grandparents listened to the radio. My parents got a TV. I'm connected to the whole world through my computer

If you go back even further. A modern (civilized) westerner wouldn't last a week if they got lost in the forest. Our ancestors wouldn't have lasted a week in the city.

The point being here that change is a constant. Not wanting things to change won't stop it and *our* unwillingness or inability to keep pace with the change does *not* mean that the youth have issues. It means *we* get left behind.

BTW, teenagers I know keep a lot better tabs on what their friends are doing with twitter and texting than I ever did.... Not every change is for the worse.

R..

[gypsyjim]

I Tell me you haven't gotten a weird look when you hand the drive through person a penny and some bills :confused::rofl3::rofl3::rofl3:
Confused? They look lost at sea!:beerchug:

[Kingpatzer]

To my knowledge, PADI has allowed the electronic table calculator thing to be part of their training for some time. Both of my kids had one for their OW certifications.

The idea that using an electronic table / calculator defeats understanding is a difficult position to defend. The tables themselves are a simplified presentation of complex calculations. They are a short cut.

If the electronic table calculators decrease fundamental understanding, then the tables themselves do the very same thing for the very same reasons.

It is a spurious and hypocritical charge devoid of merit - unless one is advocating that students should do the base calculations to build their own NDL tables, then the students are already using pre-composed calculations. Those calculations are being presented on paper rather than on an LCD display, but there is no difference beyond that.

[Blackwood]

The idea that using an electronic table / calculator defeats understanding is a difficult position to defend. The tables themselves are a simplified presentation of complex calculations. They are a short cut.

If the electronic table calculators decrease fundamental understanding, then the tables themselves do the very same thing for the very same reasons.

It is a spurious and hypocritical charge devoid of merit - unless one is advocating that students should do the base calculations to build their own NDL tables, then the students are already using pre-composed calculations. Those calculations are being presented on paper rather than on an LCD display, but there is no difference beyond that.

I could not agree more. Well said.

[Kingpatzer]

Its a little different-when you make a mistake on a math test b/c you had to do it by hand, your not going to die of the bends. At least I would hope not.


I'm pretty sure many engineers, architects, physicians, pharmacologists and similar professions are actually quite likely to kill people with mathematical mistakes.

You will find that in those fields of study, calculators are not only encouraged, but typically required for even entry level courses.

[jmorriss]

I'm pretty sure many engineers, architects, physicians, pharmacologists and similar professions are actually quite likely to kill people with mathematical mistakes.

You will find that in those fields of study, calculators are not only encouraged, but typically required for even entry level courses.

Your right I think I would find that-because I am a Civil Engineer.

Engineering courses require calculators and encourage the use of the text book in the higher level design courses.

However, the higher level math (Calc I, II, III, Differential Equations) behind the theories forbids the use of even a simple 4 function calculator.


But we aren't talking about something that add, subtracts or integrates dive times for you in terms of adding residual nitrogen to your dive time-we are talking about a computer program that prompts you for a given set of conditions and spits out an answer-there is no thought involved, no back checking, no glancing at the nearby lines on the table to see if your answer makes sense-just "plug and chug."


In my line of work we have a wonderful set of tools to design pretty much anything with a few mouse clicks. This is a wonderful time saver-one could argue that you no longer even need a trained engineer to design this massive wonders.

That is until the computer gives you an answer that doesn't make sense, or you take it as pure gospel. It is the understanding of the how behind the electrons moving in your digital dive table that is important. Computer programs are tools-you put the wrong data in you will get crap out-there is no question. You have to be intelligent enough to know the basics of what is going on inside its 'brain.' Am I stating that you have to be able to derive the formula for nitrogen loading and dispersal from the body? No-but you should be comfortable enough in the basics to see what is going to happen on the table as you progress and comprehend the rather simple pattern before you.

Technology is a great thing-but it is not the be all and end all-its a tool to assist is in achieving an end result faster-not to replace something that isn't already there. Americas education system is a laughing stock to the knowledge received in other parts of the world-its the continued mentality of "Johnny, I am sorry you don't understand the basic math in front of you, we need to equalize you to the other students around you, so here is a calculator."

Standards in many areas of the public and recreational education system are getting lower and lower. The results are not promising.


As Ron White says "You can't fix stupid."

[Kingpatzer]

Your right I think I would find that-because I am a Civil Engineer.

Engineering courses require calculators and encourage the use of the text book in the higher level design courses.

However, the higher level math (Calc I, II, III, Differential Equations) behind the theories forbids the use of even a simple 4 function calculator.


I'm not sure when or where you went to school.

In my own education, I was using calculators from geometry forward, from the calculus courses and right through graph theory and numerical methods. Indeed, from Calc III forward we were required to have symbolic calculators -- an HP graphic calculator was a department requirement for mathematics majors.

Once into areas of numerical analysis, multivariate calculus, applied fourier analaysis, and the real meat and potatoes of what constitutes mathematics we ditched the calculators for MatLab, Mathematica and other various high end mathematical computational tools.

I graduated in 1990.

I don't recall a college math course where we were not encouraged, if not required, to have a calculator on hand.




But we aren't talking about something that add, subtracts or integrates dive times for you in terms of adding residual nitrogen to your dive time-we are talking about a computer program that prompts you for a given set of conditions and spits out an answer-there is no thought involved, no back checking, no glancing at the nearby lines on the table to see if your answer makes sense-just "plug and chug."
The same is true for table usage. A table provides a set of numbers that you drop into a formula that has been given. The values in the table are derived from a set of underlying computations of which the user is typically grossly ignorant. There is nothing in the use of tables that dictates or creates understanding - it is merely 'plug and chug.' Everything is a lookup. There is no requirement for any external calculations or understanding -- which is why an average 12 year old is capable of being certified.

You are arguing against someone using a table to look up the sin 45* compared to pushing the buttons on a calculator. There is no difference in effect or understanding. None. There is no lost content or continuity in information here. There is no difference in process.

What you're arguing is that someone should not go through the same steps using buttons rather than using pencil and paper because paper is inherently superior because it is paper.


Again -- if you were arguing that the person should have to derive the underlying formulas used to build the tables, you'd have a case -- for then you would have a different content to the education that is being offered. But there is no change of content here, only of method.

Right and wrong answers from table usage, be those tables paper or electronic, comes not from an individual act of doing a lookup, nor from the inherent properties of the way the table is presented -- but from prolonged exposure and usage.

To that end, I'd offer that the electronic tables are a better pedagogical tool. Anecdotally, when my children where certified, they spent hours putting dive profiles into their little calculators and seeing the results. I certainly did not do that when learning with paper tables. I seriously doubt my kids would have either. They used those electronic tools repeatedly as a form of recreation because it was a new electronic toy, and was not seen as work. I completely believe that at the end of their OW courses, at the ages of 11 and 13, that they had a far superior understand of table relations than I did -- even though I have the education and background to actually understand the underlying formulas used to produce the tables and have a far superior understanding of table usage per se.

[simmonsjr]

From what I was told at two separate dive shops the switch to the eRDP was a PADI mandated issue that they did not have any control over. I don't think that the issue was financial; from what I remember the eRDP is not that much more expensive then the tables that I learned off of and about the same price as the Wheel. If I had to hazard an opinion I would have say that they are attempting to make the sport less intimidating for the "e-generation." That is not to say that I agree with the idea; there is a lot that is lost when the only thing you are doing is punching numbers on a screen, but how many people do anything longhand these days? Most of them expect to be able to use a calculator.

[roturner]

From what I was told at two separate dive shops the switch to the eRDP was a PADI mandated issue that they did not have any control over.

This is factually untrue.

The change PADI made makes teaching tables OPTIONAL

If a particular shop or instructor decides to stop teaching tables it their choice. PADI is not forcing anyone to change anything at this point.

R..

[simmonsjr]

Good to know. Thanks for clearing it up.

Jason

[Kingpatzer]

I suspect that the majority of shops will make the move away from the tables however. The eRDP is an up-sale, and few shops are going to pass up the option to turn this policy change into a way to demand more money from their customers.

[Blackwood]

To that end, I'd offer that the electronic tables are a better pedagogical tool.

I'd add to that:

Dive Computers have the potential to offer the most complete picture of applied decompression theory.

Yes, electronic tables make it quicker to run through examples, but they are still for the most part uncommon (i.e. square profile) examples.

A dive computer can show a diver in real time how the boundary conditions (depth and time) affect the theoretical gas loading maths for the profiles they are actually diving.

To the best of my estimation, that's far more valuable than the basic square dive table/e-table understanding which can be summarized as "the deeper I go, the shorter my stay."

[boulderjohn]

I

A dive computer can show a diver in real time how the boundary conditions (depth and time) affect the theoretical gas loading maths for the profiles they are actually diving.
"

Most computers also allow the user to download the profile to their computers and get a complete graphical display of their tissue loading throughout the dive. They can usually see bar graphs showing how each theoretical tissue ongasses and off gasses. They see which ones become saturated and when. They see which ones approach critical M-values during ascent.

Though to see that in a table.

[Teamcasa]

Most computers also allow the user to download the profile to their computers and get a complete graphical display of their tissue loading throughout the dive. They can usually see bar graphs showing how each theoretical tissue ongasses and off gasses. They see which ones become saturated and when. They see which ones approach critical M-values during ascent.

Though to see that in a table.

Like this from Oceanic

http://www.scubaboard.com/gallery/data/3840/DiveView.jpg

[Thalassamania]

Ya'll are having the wrong fight. It doesn't matter if someone uses tables, or a calculator, or a computer ... as long as they understand what they are doing, get the correct answer and act on that answer appropriately.

The real issue is not which is "best" since they all work and have pros and cons, the real issue is that computers and calculators have become emblematic of courses that rush people through and do not invest the time required to assure an understanding of the topic, they just check to see if it's the right answer or if the diver knows which which part of the display screen should control they should trust their well being too.

Knowing the propensities of the sports diving industry to cut corners, we offered a clear warning about this issue back in the early days of computers in the Proceedings of the AAUS Dive Computer Workshop, and I am not surprised to see that it has come to pass. "No tables" or "computer only" classes have become, in many cases, nothing more than code words for not providing an adequate background in decompression theory and models.

[jmorriss]

The real issue is not which is "best" since they all work and have pros and cons, the real issue is that computers and calculators have become emblematic of courses that rush people through and do not invest the time required to assure an understanding of the topic, they just check to see if it's the right answer or if the diver knows which which part of the display screen should control they should trust their well being too.



Thats what I was trying to get at :D

[Blackwood]

Most computers also allow the user to download the profile to their computers and get a complete graphical display of their tissue loading throughout the dive. They can usually see bar graphs showing how each theoretical tissue ongasses and off gasses. They see which ones become saturated and when. They see which ones approach critical M-values during ascent.

Sure. That's valuable and very interesting, but I think maybe superfluous to the general understanding necessary to identify 'bogus' numbers. I don't think that everyone necessarily needs to look at what's happening theoretically within each mathematical compartment.

What I was getting at is the 'end result' of NDL mathematics, i.e. The NDL, which is am abbreviation for all the constituent compartments, their associated loadings, and the ascent profile (quite often linear @ 60fpm).

A diver can bumble around for 20 minutes at 100 feet. A dive table may have told him "okay, now you've hit your NDL and you must make an immediate ascent at whatever rate else you're at a high risk of DCS." But he could also watch what the NDL display on his computer does as he ascends. On the face of it, the NDL is increasing (from zero to some non-zero value). In the background (math), that means he's offgassing.

I think in-water offgassing is often glossed over by basic table lore. While the offgasing of a constant rate ascent is intrinsic to the computation of an NDL, the way most NDL tables read is that offgasing takes place on the surface.

IMO, a diver who does 10-20 dives and pays diligent attention to the NDL display will have a better practical understanding of decompression theory than a diver who plans and executes 10-20 dives using NDL tables.


"No tables" or "computer only" classes have become, in many cases, nothing more than code words for not providing an adequate background in decompression theory and models.

I bet you'd find that many BOW courses which still use tables leave the students with the same inadequate background.

[roturner]

I bet you'd find that many BOW courses which still use tables leave the students with the same inadequate background.

Maybe. However, I think, even though I'm not opposed to the idea, that there is a risk involved in teaching computer only that the whole idea of dive planning will eventually be brought back (through lowering agency standards and/or the laziness of some instructors) to this:

-- jump in, watch your SPG and make sure this number never gets to zero.

Like it or not, tables *force* instructors to somehow (usually badly) talk about on-gassing and off gassing to some extent. For a decent instructor the difference btween tables and computers is pretty much moot but to the lazy ones... well... it will give them new improved ways to avoid actually teaching students about diving.

R..

[Thalassamania]

I think in-water offgassing is often glossed over by basic table lore. While the offgasing of a constant rate ascent is intrinsic to the computation of an NDL, the way most NDL tables read is that offgasing takes place on the surface.

That's part of the theory material that I find is often dropped, it's not peculiar to one form of display or another. In point of fact I think that it is likely better covered in a table based presentation because with a table based presentation it is essential that the diver learn how to deal with variations in time of ascent, again the issue should not be the type of information display but rather the content of the course.


IMO, a diver who does 10-20 dives and pays diligent attention to the NDL display will have a better practical understanding of decompression theory than a diver who plans and executes 10-20 dives using NDL tables.

I bet you'd find that many BOW courses which still use tables leave the students with the same inadequate background.So let's stop wasting time on the red herring of tables vs. computers and deal with the real issue of what need be provided in a course so that a student can provide informed consent concerning their exposure to hyperbaric conditions.

[boulderjohn]

So let's stop wasting time on the red herring of tables vs. computers and deal with the real issue of what need be provided in a course so that a student can provide informed consent concerning their exposure to hyperbaric conditions.

I think I can summarize. Correct me if I am wrong.

Most or all of us are saying the same thing on one issue: decompression theory should be taught so that students understand why they need to stay within certain limits and why they need to ascend at certain rates.

Where we differ lies chiefly in these two positions:

Some are saying that teaching this is not the same thing as teaching the mode that is used to calculate those limits and those safe rates of ascent. Decompression theory can be taught as one concept, and calculating it can be taught as another.

Some are saying that you cannot teach decompression theory without teaching tables. If students are not taught how to use tables, they will not understand decompression theory.

Or is there more to it than this?

[mikemath]

Its a little different-when you make a mistake on a math test b/c you had to do it by hand, your not going to die of the bends. At least I would hope not.

As I said in my earlier post, I believe the eRDP will decrease the error rate when calculating a dive plan, based on the types of mistakes common with the table form. That's speculation, but PADI may have some numbers backing it up--would be interesting to see.

[boulderjohn]

As I said in my earlier post, I believe the eRDP will decrease the error rate when calculating a dive plan, based on the types of mistakes common with the table form. That's speculation, but PADI may have some numbers backing it up--would be interesting to see.

My wild guess is that 50% of the table errors my students make on exams (thankfully, not that many) come from messing up the columns and picking the wrong number or letter.

[Thalassamania]

I think that you're basically right, but that there is a little more too it. Table, computer, it doesn't matter to me, a good understanding of the background and a diver should be able to use either without a bunch of fuss. The problem lies in that the table advocates tend to be the older line instructors who have usually (not always) provided that firm theoretical underpinning while those who slough it off with nothing more than saying, "don't let that number go to zero," do not tend to provide the basic decompression information.

[jmorriss]

My wild guess is that 50% of the table errors my students make on exams (thankfully, not that many) come from messing up the columns and picking the wrong number or letter.

I think some of it is also from the fine print on the back of the table.

[Kingpatzer]

I think some of it is also from the fine print on the back of the table.

No lie! I have no idea how I'm going to read those things in a few years time. I have fine macro vision, but enough of an astygmatism to make reading the print on a typical table next to impossible in anything except the best lighting conditions. Is that a 6, and 8 or a B? I have no idea ...

As for the larger discussion -- I absolutely agree that at issue should be the quality of instruction. The debate over paper tables versus eRDP is specious.

[Teamcasa]

I overhead the owner explaining to a prospective OW student that they no longer teach the tables but exclusively use the calculator.

It just seems along the lines of some other concerns on here that the agencies may be dumbing down the OW classes. I'd really like to see some comments from instructors on this one.

The dumbing down is one thing, teaching how to read and understand the tables vs computers is another.

Most recreational divers use their computers more than the tables but that does not mean they were not taught what nitrogen loading is and how to use the tables.

The problem I sometimes see is new divers that don't use the tables AND do not know how to operate and read their computers.

Ya'll are having the wrong fight. It doesn't matter if someone uses tables, or a calculator, or a computer ... as long as they understand what they are doing, get the correct answer and act on that answer appropriately.

Wow, 100 posts and we are back to the beginning again.

[boulderjohn]

I think that you're basically right, but that there is a little more too it. Table, computer, it doesn't matter to me, a good understanding of the background and a diver should be able to use either without a bunch of fuss. The problem lies in that the table advocates tend to be the older line instructors who has usually (not always) provided that firm theoretical underpinning while those who slough it off and nothing more than say don't let that number go to zero, do not tend to provide the basic decompression information.

Now, let's be careful about hasty generalizations. ;)

When I first learned (I didn't even know there were dive computers when I took the class), my instructor taught me a step-by-step sequence of actions to come up with the correct answer to a table problem. I learned that sequence of steps well and got all the answers correct on the exam.

Later on, long after that class, I learned something about decompression theory. Much later I learned a lot about it. As I have said in some of the 30-40 other threads on this topic (OK, OK, I exaggerate), I teach my students what they need to know about deco theory before we even mention the tables.

[jmorriss]

I had a pretty good handle of decompression theory going into OW Class thanks to 10 years of teaching from Clive Cussler and Dirk Pitt- but thats just me :read:

[roturner]

Yeah,

I learned in 1984. Recreational divers weren't using computers yet. I learned the tables, in fact, I made so many dives using the tables that I had a large part of them memorized.

And I never knew the first thing about deco theory until I decided to get serious about diving and stumbled across something about it on the internet.

R..

[Blackwood]

Wow, 100 posts and we are back to the beginning again.

Goes to my Third (http://www.scubaboard.com/forums/4318238-post140.html) Law of Scubaboardynamics:

"Each thread has a maximum number of pertinent posts. Once that 'critical mass' has been reached (often around post #2), the thread will explode into a mass of either repetitive or irrelevant drivel. Many 'thanks' will follow."

:D

[boulderjohn]

I have benefited from this thread. I believe the next time I teach decompression theory I will make use of a series of images from a computer dive profile to show tissue on gassing and off gassing from the early parts of a dive to the end.

http://www.scubaboard.com/gallery/data/500/divelog1.gif

http://www.scubaboard.com/gallery/data/500/divelog2.gif

http://www.scubaboard.com/gallery/data/500/divelog3.gif

http://www.scubaboard.com/gallery/data/500/divelog4.gif

[Teamcasa]

Here are a few more example John,
These show how and when the Safety Stop help drop the NL levels.

http://www.scubaboard.com/gallery/data/3840/medium/DiveView2.jpg

http://www.scubaboard.com/gallery/data/3840/medium/DiveView3.jpg

[RetMTFE]

For a sport that places so much emphasis on redundancy and having a back up for their back up, I'm amazed at the number of responses that are along the line of, "I've got a computer and it's more acurate. Who needs tables."
Personally, I love my computer but I don' plan to be the one that's on day two of a week long live aboard who can't dive anymore because my computer went belly up and I don't know how to use the tables.

[promocop]

where can I buy an abacas?

[simmonsjr]

promocop, ask and ye shall receive. You can purchase your abacus here: American Science & Surplus : Computer Revolt (http://www.sciplus.com/singleItem.cfm/terms/14197/cartLogFrom/froogle). It's waterproof, never needs batteries, and is really quite stylish. It can be yours for only $8.95 plus S&H. You may be on to something . . . Orders anyone?;)

[Kingpatzer]

where can I buy an abacas?

Here (http://www.citivu.com/usa/sigmaed/) :eyebrow:

[Teamcasa]

For a sport that places so much emphasis on redundancy and having a back up for their back up, I'm amazed at the number of responses that are along the line of, "I've got a computer and it's more acurate. Who needs tables."
Personally, I love my computer but I don' plan to be the one that's on day two of a week long live aboard who can't dive anymore because my computer went belly up and I don't know how to use the tables.

The reality is that computers replace the RDP (tables). RDP's are not a back up to the computer, but the computer can be a backup to the RDPs.

[mikemath]

The reality is that computers replace the RDP (tables). RDP's are not a back up to the computer, but the computer can be a backup to the RDPs.

I'm not sure if I'm reading your comment right, but I disagree that the RDP cannot act as a back-up for a computer. A couple weeks ago, one of the divers I was with had her computer die after the first dive (turned out to be a little bit of water in the battery compartment--dried off and was fixed). Not wanting to waste some good conditions, we pulled out her RDP table, plugged in our bottom time from the first dive, and figured out our NDL for the second dive, and she dove using her watch and gauges (luckily she had a console-mounted SPG in addition to the air-integrated computer). Sure, my computer showed I still had significant time left at the end of the dive, but we had a great dive that we would have aborted if we didn't have the RDP as a fallback. Of course, if your only computer fails mid-dive and you didn't plan the dive with an RDP to figure out NDL, the RDP won't help you and you'll need to abort the dive.

[roturner]

Yeah if she was still "on the table" then you could do that. Computers, however, can easily put you off the table.

I think (although I wouldn't advise this) that if you were "off the table" that you could assume group Z (the highest nitrogen loading the table will allow) and then go from there to fall back. Tables have natural padding to them though so I'm not sure this is wise.

R..

[awap]

Yeah if she was still "on the table" then you could do that. Computers, however, can easily put you off the table.

I think (although I wouldn't advise this) that if you were "off the table" that you could assume group Z (the highest nitrogen loading the table will allow) and then go from there to fall back. Tables have natural padding to them though so I'm not sure this is wise.

R..

I believe the biggest problem with this is that it is unproven so no one can say that is safe. But that is my plan for dive sites and profiles that I have done before.

[Blackwood]

I believe the biggest problem with this is that it is unproven

But what is (proven)?

[mikemath]

But what is (proven)?

The RDP (and earlier Navy tables) have been extensively tested to determine the degree to which they prevent decompression sickness. The RDP testing process used ultrasound measurements to identify bubble formation resulting from thousands of dives, while the Navy table development used actual DCS symptoms observed in their studies (gotta feel bad for the sailors who were involved in that program!).

Anything not explicitly advocated by these tables is "unproven" because it hasn't been subjected to the same testing rigor and is not known to reduce the likelihood of DCS to a sufficient degree by evaluating a large statistical sample.

[boulderjohn]

The RDP (and earlier Navy tables) have been extensively tested to determine the degree to which they prevent decompression sickness. The RDP testing process used ultrasound measurements to identify bubble formation resulting from thousands of dives, while the Navy table development used actual DCS symptoms observed in their studies (gotta feel bad for the sailors who were involved in that program!).



Ask Doc Deco from ScubaBoard for details--he was part of the team that developed the RDP.

[Teamcasa]

I'm not sure if I'm reading your comment right, but I disagree that the RDP cannot act as a back-up for a computer. A couple weeks ago, one of the divers I was with had her computer die after the first dive.

Not wanting to waste some good conditions, we pulled out her RDP table, plugged in our bottom time from the first dive, and figured out our NDL for the second dive, and she dove using her watch and gauges

Of course, if your only computer fails mid-dive and you didn't plan the dive with an RDP to figure out NDL, the RDP won't help you and you'll need to abort the dive.


Yeah if she was still "on the table" then you could do that. Computers, however, can easily put you off the table.

I think (although I wouldn't advise this) that if you were "off the table" that you could assume group Z (the highest nitrogen loading the table will allow) and then go from there to fall back. Tables have natural padding to them though so I'm not sure this is wise.

R..

Correct, to a point. By all rights, if your computer failed and the dive information was unavailable, then by all rights, you are done diving for the day.
OTOH
Most divers know if they were pushing the limits and their buddy's computer still had plenty of NDL time left, chances are that most of us would do a extended surface interval, switch to the RDP to plan the subsequent dives.

So much of this is conjecture and dependent on many factors like the finished dive profile, the planed next dive(s) and the experience level of the divers plus the availability of redundant gear. (Watches, SPG ect.)

But in any event, the RDP would not the backup (since it did not help in the previous dive) but more a replacement of the failed computer.

[guamguy]

I think computers are great! But, they are no substitute for learning the tables. When I was OW certified ('94), computers were just starting to come out. I don't think we even covered them in the class. We had the tables drilled into our heads, and we were tested to make sure we knew how to use them. Yes, I dive with a computer, but I also take a look at the tables when I'm planning a dive, just in case the computer takes a $h!t so I don't have to abort the dive.

[medicdiver738]

I just took my OW class a month ago and all did was use tables. I did not use a computer untill after my OW class when I bought one and even then while diving with my instructor for fun he still made me use the tables. As far a the little calculator goes I agree with others that it is just another PAID money maker......oops I meant PADI.