PADI tables finally going away?

[boulderjohn]

Exactly my point Boulderjohn, notwithstanding your curiously strange conclusion of a false analogy, and not advocating the use of dive tables as a basic applied reference for decompression theory and planning . . . again heuristically and from an Education & Learning perspective IMHO, I beg to differ: my analogy is valid.

I dipped back into the experiences I had years ago teaching grammar in an attempt to find the subjects, verbs, etc. in that construction that would help me understand your point, but I really don't know what you were actually saying there. Education and learning theory is my vocation, and I explained why your analogy was false. In reply, you simply said I was wrong and used the pejorative and insulting phrase "curiously strange conclusion" without any explanation of why my conclusion was curiously strange. Usually when one has a valid point of view, the response will be to explain why it is valid. When one responds instead with an insult and no content whatsoever, it is usually a sign that one does not have a valid response.

Ahh, but we all still learn arithmetic and math in school even though calculators ere the norm in classrooms, charges and change due is all calculated by machine at the grocery store, most everyone has an electronic device on him (phone) to figure out who owes what when dividing the bill in a restaurant, etc.

I will try again.

The analogy of arithmetic instruction/calculators v. tables/computers is not valid.

First, you must understand arithmetic to use a calculator. Arithmetic is a concept and is more closely analogous to decompression theory. Just as the calculator is a tool that helps a someone perform arithmetic, the dive computer is a tool that helps a diver calculate decompression needs. Just as you need to know arithmetic to use a calculator, you need to know decompression theory to use a dive computer effectively.

A more apt analogy would be to the abacus. There are two well known tools that help people perform arithmetic, the abacus and the calculator. One needs to understand arithmetic concepts to use either one, but you don't need to know how to use the abacus to use a calculator. Similarly, you need to know decompression theory in order to use both the tables and the dive computer, but you don't need to know how to use tables to use a dive computer.

A second point is that the ability to perform arithmetic functions without a calculator is an important skill that will continue to be needed throughout one's life. In its 2008 report, the National Math Panel quite correctly identified those needs in explaining why this is such a critical skill to master. In contrast, there is no independent need to use a table if one is using a dive computer.

I think the misunderstanding comes from the way many instructors have historically taught decompression theory. Many have taught it at the same time they teach how to use tables to calculate decompression needs. That leads people to make the natural mistake of assuming it is necessary to understand the tables in order to understand decompression theory. It is not.

I still teach tables (or the eRDPml, depending on what my students learned in their independent study) myself, but I teach decompression theory long before I reach that point in my class. My students understand how their bodies take on and release nitrogen long before we talk about how to measure and plan for that process. When I reach that point in my instruction, I could teach any method for calculating decompression needs-- tables, eRDP, or computer.

By the way, I do not use a computer with decompression diving on square profiles, but I do recognize it as a valid tool used safely by nearly all recreational divers.

 

[Splitlip]

Learning arithmetic is not a good analogy here. Learning to use a sliderule is a far better one. Sliderules are not electronic (nor are they analog, Kev), but that does not make them easier or more reliable than a calculator.

So tell me: do they still teach students how to use a sliderule today? I don't think so.

I used slide rule junior and senior years in high school and my Freshman and Sophomore years. (calculators at exam time were verboten until my Junior year) I don't recall that we were ever "taught" how to use one. A slide rule is intuitive if you understand math. Even when using one, you still had to carry exponents and places in your head or on paper. (Apollo XIII)

I agree a calculator is easier and I would say more accurate, not reliable. A slide rule does not need batteries.

That aside, Imagine trying to teach grade school kids how use a calculator without teaching them math first..

I admit, it is not great comparison to compare calculator use to dive computer use, however I have had 3 computer failures in the the last 10 years or so. In all three cases I finished the dives and in 2 cases I finished the day out with tables.

In the 3rd case, I just blew off the last dive of the day when I loaned my fins to somebody who lost one.

The op where my daughter did her open water taught and tested on tables. Then devoted a session to computers. Uwatec Aladdins only as that is what is in their fleet.

 

[Splitlip]

A more apt analogy would be to the abacus. There are two well known tools that help people perform arithmetic, the abacus and the calculator. One needs to understand arithmetic concepts to use either one, but you don't need to know how to use the abacus to use a calculator. Similarly, you need to know decompression theory in order to use both the tables and the dive computer, but you don't need to know how to use tables to use a dive computer.

A second point is that the ability to perform arithmetic functions without a calculator is an important skill that will continue to be needed throughout one's life. In its 2008 report, the National Math Panel quite correctly identified those needs in explaining why this is such a critical skill to master. In contrast, there is no independent need to use a table if one is using a dive computer.

I think the misunderstanding comes from the way many instructors have historically taught decompression theory. Many have taught it at the same time they teach how to use tables to calculate decompression needs. That leads people to make the natural mistake of assuming it is necessary to understand the tables in order to understand decompression theory. It is not.

Excellent points!

I for one certainly did not need tables to learn decompression theory.

I sat in my daughter's OW class. I think some of the students do in fact need visuals and hands on make some things sink in.

 

[boulderjohn]

I sat in my daughter's OW class. I think some of the students do in fact need visuals and hands on make some things sink in.

I do use visuals. I have two PowerPoints. The first one shows how nitrogen diffuses from the air being breathed into the blood and then into the tissues. They see that when there are more Ns in the air section because of depth, it will diffuse into the blood and tissue. They see how the opposite happens when they ascend.

The second PowerPoint, which I have just made and has not yet been used, uses a computer printout of an actual downloaded dive profile. Students see how the theoretical tissues take on gas as the dive progresses. They see how the tissues are theoretically loaded as the diver approaches the no decompression limit, and they see how they give off gas on the ascent. They also see the beginning of the second dive to see how the tissues had changed during the surface interval, and they can compare a second dive start with a first dive start to see the effect of residual nitrogen.

If you want visuals, you can get them without the need for a table.

 

[The Chairman]

When one responds instead with an insult and no content whatsoever, it is usually a sign that one does not have a valid response.

Chalk it up to faith or simple dogma and it makes more sense. We are nothing but athiests to these dogmatic believers. We are going to hell no matter how much science and logic we have to back this up.

FWIW, I plan my tech dives using my PC so I have an idea what to expect, but I rely on my PDC to get me through the dive. I have yet to be bent.

 

[Splitlip]

I do use visuals. I have two PowerPoints. The first one shows how nitrogen diffuses from the air being breathed into the blood and then into the tissues. They see that when there are more Ns in the air section because of depth, it will diffuse into the blood and tissue. They see how the opposite happens when they ascend.

The second PowerPoint, which I have just made and has not yet been used, uses a computer printout of an actual downloaded dive profile. Students see how the theoretical tissues take on gas as the dive progresses. They see how the tissues are theoretically loaded as the diver approaches the no decompression limit, and they see how they give off gas on the ascent. They also see the beginning of the second dive to see how the tissues had changed during the surface interval, and they can compare a second dive start with a first dive start to see the effect of residual nitrogen.

If you want visuals, you can get them without the need for a table.

Good point again.

 

[John_B]

Learning arithmetic is not a good analogy here. Learning to use a sliderule is a far better one. Sliderules are not electronic (nor are they analog, Kev), but that does not make them easier or more reliable than a calculator.

So tell me: do they still teach students how to use a sliderule today? I don't think so.

I started to reply about sliderules yesterday but it seemed like a beaten horse. Since we're bringing it up again...

When I first learned to analyze circuits we used sliderules as a tool. Mostly because it made you think about the orders of magnitude we were working with when facing mA and and kΩ or µF and MΩ. And, as I found out later, it also really helped the instructor "see" if you "got" the concepts or not. So the sliderule helped us understand (and demonstrate mastery of) the concepts, after which we moved on to calculators and (later) computers.

IIRC in accounting, we also did a complete manual P&L and balance sheet through trial balance with 13-column ledger paper, and for the same reasons: to develop proficiency and demonstrate mastery. I could go on...

It's this that's exactly what's missing from some newer divers I've seen recently. They don't seem to have any idea where the magic number on their PDC comes from or even the rudimentary idea of how it's calculated.

This is precisely why PDCs should be taught from the beginning. Reading the manual on how to start them up does little to teach you how to use this tool effectively. Spending valuable time teaching them something that they will abandon as quickly as possible is foolish. Teach them to use the tools they will be diving with and leave the hubris behind.

But each PDC does this a differently and most of the interfaces to punch in the numbers are positively awful. No wonder people don't actually use them for dive planning. And I don't see that someone who isn't capable of learning tables (and the PADI tables aren't the most intuitive anyway) is somehow going to "get" punching in their planned SI and their planned depth next for the next dive. The reality is that, by definition, divers who "fly" their computers don't do any actual dive planning in the first place.

Now I'm not saying there is any implicit value in knowing that x dive followed by y surface interval puts you in some specific pressure group, but I am saying that giving people a complete pass on tables sends the message loud and clear that dive planning isn't important because they can just "fly the PDC until it beeps at them to ascend".

Until the day they can't "just ascend" (for whatever reason) and they find themselves at 80' with 20 minutes of deco on their PDC without enough air in their tank to do the deco. And at that point maybe they become a liability to another diver or divemaster that I do care about.

I don't just object to these divers' behavior because they are a hazard to themselves, I object because their negligence can impact the lives of good people who take their own safety seriously. And by extension I object to the instructors who insist on letting these divers loose on the rest of the planet.

 

[lowviz]

..........the majority of people who are proponents of using tables appear to be divers that have stepped outside of the realm of a recreational diver..........I have no desire to enter into the realm of decompression diving,.........

The remaining snippets (above) are what I was responding to.

The problem I find with this statement is that I have no idea what it means to "go into deco." .............what did the poster mean by his comment?
.................

First, apologies for the delay. My real life keeps interrupting my virtual one.

"Go into deco" was an admittedly obtuse way to respond to the OP's statement: "I have no desire to enter into the realm of decompression diving".

OK, give me a hand here as I've obviously missed making my point. The tables I refer to on my left hand include the U.S. Navy 10 min omitted stop procedure. For the recreational diver who has "no desire to enter into the realm of decompression diving", what would you suggest as a backup plan for their single PDC?

My UWATEC PDC doesn't reset to air after a predetermined amount of time. I once did a dive on Nitrox 36 setting while diving on air. (Didn't go into deco but creeped me out anyway.) That was a real wake-up call for me. I checked repetitive NDL's from tables from then on. Not at all hard to do. That simple procedure catches a lot of oversights. -the lower spinal cord is usually the first to go. I'd rather keep that...

 

[Splitlip]

My UWATEC PDC doesn't reset to air after a predetermined amount of time. I once did a dive on Nitrox 36 setting while diving on air. (Didn't go into deco but creeped me out anyway.) That was a real wake-up call for me. I checked repetitive NDL's from tables from then on. Not at all hard to do. That simple procedure catches a lot of oversights. -the lower spinal cord is usually the first to go. I'd rather keep that...

I've seen them go both ways.

So, assuming you don't know tables or planning (new diver here) as soon as you realize your error, you would surface and not dive until your computer zeros out again.

If you did as my buddy did 3 weeks ago, (he was diving 36 on the first dive but his computer was set to 21). It put him in deco and locked him out. He probably should have called DAN and admitted himself to the ER for a chamber ride. Instead, he finished the dive and the day using tables.

Maybe this is the new reality. When I was a kid, Dad taught me to change a flat tire. My daughter was taught to call AAA.

 

[Kingpatzer]

For the recreational diver who has "no desire to enter into the realm of decompression diving", what would you suggest as a backup plan for their single PDC?

If the PDC fails on the dive, you end the dive just as you would for any other critical equipment failure. For a PDC that dies before the dive, rent a replacement or ask someone to help you with tables and rent a bottom timer and depth gage.

My UWATEC PDC doesn't reset to air after a predetermined amount of time. I once did a dive on Nitrox 36 setting while diving on air. (Didn't go into deco but creeped me out anyway.) That was a real wake-up call for me. I checked repetitive NDL's from tables from then on. Not at all hard to do. That simple procedure catches a lot of oversights. -the lower spinal cord is usually the first to go. I'd rather keep that...

So, instead of just adding a procedure of checking that the PDC is set correctly while you plan your dive, you added a more complex procedure of cross-referencing a table that is probably not even built on the same model.