PADI not teaching dive tables anymore?

[lowviz]

...//... See what I'm on about? A computer just gives you numbers, but it can't be blamed if the diver is an idiot, and it won't make an idiot out of someone who wasn't one to begin with. ...//...

Yes, I think that I see. It appears to me that you object to my implication that computers are "bad". I own four of them.

I'm more toward just showing that the "tables" crowd aren't necessarily a bunch of Luddites than I am taking an anti-computer stance. It all hinges on the effort required to actually plan a dive.

And, yes, give a slacker a DC and he will be indeed be safer. Not optimal, mind you, just significantly safer.

 

[Diver0001]

I'm more toward just showing that the "tables" crowd aren't necessarily a bunch of Luddites than I am taking an anti-computer stance. It all hinges on the effort required to actually plan a dive.

I wouldn't characterize people who prefer to use tables as Luddites either.... anymore than I would characterize people who prefer to use computers as "dumbed down".

I understand that planning the dive takes on a slightly different character if you use a computer but seriously the constant assertions in these threads that using a computer somehow dumbs down diving is completely and utterly absurd. I'm not sure if that's what you were saying or not, but it's how the OP started this thread and it's the lowest common denominator in many such threads we've had in the past.

R..

 

[lowviz]

...//... I understand that planning the dive takes on a slightly different character if you use a computer but seriously the constant assertions in these threads that using a computer somehow dumbs down diving is completely and utterly absurd. I'm not sure if that's what you were saying or not, but it's how the OP started this thread and it's the lowest common denominator in many such threads we've had in the past.

R..

OK, I now get it. I think that a new diver that wants to start out by being "rigorous" will see a DC as an incomprehensible device while tables somehow seem more transparent. It takes a bit to see that they both do similar things, but DC's are far more adaptive on an actual dive. I prefer to keep sharp with respect to the ability to estimate, yet I like to dive DC's.

 

[Diver0001]

OK, I now get it. I think that a new diver that wants to start out by being "rigorous" will see a DC as an incomprehensible device while tables somehow seem more transparent.

Yeah, well... this point is going to require instructors to make a bit of shift too. Too many instructors teach how to use a table and THINK they have taught something about deco theory. That's where I think all the comments about dumbing down come from. If one assumes that "tables = deco-theory" then naturally you will assume that if you're not teaching tables then you're not teaching deco theory.

As a matter of fact, what the new technology requires of instructors is to teach deco theory much more thoroughly than they did in the past and then to present both tables and computers as different ways to view that theory in terms of practical dive planning. In any case that's exactly what I do and I am far from unique in this respect. I have no trouble at all explaining tables or computers as required. Moreover, instructors who take a step back from using tables as a "crutch" (speaking of which) to explain deco theory seem to give students a better understanding of it than they did in the past.

If I think back, I was taught to dive with tables and made my first 600 or so dives using them.... but did I understand deco theory? No. I understood that going over the NDL was the diving equivalent of sailing off the edge of the world. It wasn't until the internet became popular and I had access to more and better information that I really started getting a grasp of deco theory. If it hadn't been for that, I might use a computer just like I used the tables... just don't go over the NDL and you haven't sailed off the edge of the world.

In that sense it's not surprising to me that some people ride the computer like that. Perhaps (likely?) it's a reflection of them having been taught that going over the NDL is "bad" but not how it ties in with the rest of your planning, ascent, and surface stops....

R..

 

[victorzamora]

In mathematics, there's a term not often used called Zequals. It is a method of estimation made by simplifying the math. This method of estimation is surprisingly good. Here's an explanation, if there are any nerds out there. Anyway, most people mock it because it's less accurate, harder to do, and much slower than a calculator. The point of Zequals is to give people a feel for numbers. Proponents of zequals want to teach it to the youth not so they can crunch Pi to the Billionth digit using it, but so that when they're doing rough calculations in their heads for a less-than-critical design point they can get a good reference number. Opponents of it have no real leg to stand on because the proponents know the limits, know the benefits, and still believe that it gives them a better "feel" for numbers. If nothing else, they can use it to make sure they didn't input something wrong into the calculator.

Now, I'm a 23yo Aerospace Engineering student that uses computers 20 hours a day. I use technology in practically every aspect of my life and am a HUGE proponent of people learning to use technology properly. One of my biggest pet peeves is someone that refuses to "get with the times." I have an RDP on me every time I dive. After my fiancee got certified using an eRDPml, I bought her an RDP and taught her how to use it. Why? I don't trust computers. A responsible person shouldn't. If I get to 130ft and it says my NDL is 18 minutes on air, I instinctively know it's wrong. Why? RDP. Another dive buddy would have NO idea if 18 minutes on air was right or wrong. The scariest one to me is what if you input your EANx mix wrong? That's not a flaw in the computer (which pro-DC people seem to LOVE to flaunt, that they don't "really" fail...we do). However, if it's telling you your MOD on EAN32 is 240ft....would you know it was wrong? How about 180ft? I do it by hand, and I've taught my fiancee to do the same.

I'm in a Senior Design class right now that involves us designing, building, and flying a UAV. One of the most competent members on my team put together the most brilliant structural analysis code and tested every piece of it individually AND together, and validated the data against experimental values. He went WELL above and beyond with the most elaborate Finite Element Analysis model I've ever seen (outside of a proprietary, multi-million dollar code). However, the numbers it gave him were wrong. It could've cost us our grades, graduation, and $10k worth of building materials to learn that the hard way. I had an intuition regarding the accuracy of the program. I knew what the structural capabilities were "supposed" to be. He trusted me because he had no previous experience at this scale and we eventually found an error in his code. It was a "\" instead of a "/". It then gave a number VERY close to what I had estimated. Someone who only works on a computer would have no way of knowing what it "should" be. He didn't. How is a diver supposed to "know" what the limits are if he's only ever dove with a DC?

I think RDP's are a necessary part of learning to become a diver, not because it's the most accurate. Not because it'll give you the best dive profile or that it's the least prone to failure, but because it's the easiest to UNDERSTAND properly. I don't mean learning to use it, I mean really UNDERSTANDING it. There's a huge difference. I dive a DC. If I had the money, I'd get my fiancee one as well (actually, I'd give her mine and get myself a Petrel .

PS- If I had the patience, I'd go back in and fill in all of the appropriate emoticons where they should be.

 

[boulderjohn]

I tried using a computer a couple of years ago, but it ended up just being something I had strapped to my arm. I just didn't trust it. I ended up selling it to get my son a new BC.

I get your point, but realistically, which is more likely to have significant miscalculations over time; your brain or a dive computer?

I spent a lot of time training with an agency that has no faith in computers and does not allow them on dives. Divers are to use bottom timers (or the like), keep track of their maximum depth, do mental averaging of their depth, and follow what is essentially a table to plan ascents. Two friends of mine, highly experienced divers with loads of training, completed such a dive a while ago. One of them had a computer in gauge mode with him on the dive, so he was able to download the actual dive profile to his computer. I helped them analyze the results, which revealed that they had gone deeper then they thought they had, had averaged a deeper depth than they thought they had, and had had a much, much slower ascent rate when they first left the bottom than they thought they had.

Why were we doing this analysis? To find out why they both got bent.

 

[TMHeimer]

Yeah, well... this point is going to require instructors to make a bit of shift too. Too many instructors teach how to use a table and THINK they have taught something about deco theory. That's where I think all the comments about dumbing down come from. If one assumes that "tables = deco-theory" then naturally you will assume that if you're not teaching tables then you're not teaching deco theory.

As a matter of fact, what the new technology requires of instructors is to teach deco theory much more thoroughly than they did in the past and then to present both tables and computers as different ways to view that theory in terms of practical dive planning. In any case that's exactly what I do and I am far from unique in this respect. I have no trouble at all explaining tables or computers as required. Moreover, instructors who take a step back from using tables as a "crutch" (speaking of which) to explain deco theory seem to give students a better understanding of it than they did in the past.

If I think back, I was taught to dive with tables and made my first 600 or so dives using them.... but did I understand deco theory? No. I understood that going over the NDL was the diving equivalent of sailing off the edge of the world. It wasn't until the internet became popular and I had access to more and better information that I really started getting a grasp of deco theory. If it hadn't been for that, I might use a computer just like I used the tables... just don't go over the NDL and you haven't sailed off the edge of the world.

In that sense it's not surprising to me that some people ride the computer like that. Perhaps (likely?) it's a reflection of them having been taught that going over the NDL is "bad" but not how it ties in with the rest of your planning, ascent, and surface stops....

R..

Great post. Seems what you are saying is always be conservative regardless of whether you use computer or tables or both. And that some people dive right to the NDL because they figure they're safe. I would believe that. Perhaps using a computer in some way encourages that and requires less thinking--much like when automatic transmissions came out vs. stick shift. Perhaps not. Either way, if the NDL on the tables says 20 mins. at 100' on air, I will probably be ascending at the 17 min. mark or so.

 

[drrich2]

I don't trust computers. A responsible person shouldn't. If I get to 130ft and it says my NDL is 18 minutes on air, I instinctively know it's wrong. Why? RDP. Another dive buddy would have NO idea if 18 minutes on air was right or wrong.

While computers sometimes quit working, have you (or anyone else on this thread?) ever seen one actually give wrong data? Like for 18 minutes NDL at 130 ft on air?

I think RDP's are a necessary part of learning to become a diver, not because it's the most accurate. Not because it'll give you the best dive profile or that it's the least prone to failure, but because it's the easiest to UNDERSTAND properly. I don't mean learning to use it, I mean really UNDERSTANDING it. There's a huge difference.

Understand what? I believe the majority of modern divers who learned with the tables (I was one, back in late '05) quit using them, and don't retain sufficient functional fluency through ongoing use to make that old knowledge useful.

Most divers don't 'understand' the tables that well; they simply know that the table says at this depth on that gas head up before this time passes.

One can glance at the tables and get a quick since of max. bottom time #'s for some varied depths; if you want to memorize MBT for a few depths, like 60, 80, 100 feet, and like to have those numbers in the back of your mind as a back-up measure, that's fine.

Which also addresses the example of accidentally inputting the wrong EAN mix for EAN 32 & getting a computer-generated mod. way deeper. I know from the Nitrox course not to exceed 110 feet on EAN 32, or 90 feet on EAN 36. And as a rec. diver, don't exceed 130 feet on air. The only other MOD issue I'd likely run into someday is getting a custom mix to deep dive a wreck like the Oriskany or to see sand tiger charts on NC wrecks, and for that, I'd pick a mix for the depth.

No necessity to use tables for dive planning to get those benefits.

Lowviz posted:

Would you prefer: "People have a nasty habit of relying on crutches if the crutch is comfortable enough"?

That's a good point, but the kind of people who'd pass on computers to dive with tables don't seem to me to be the kind of people who'd not plan even if they used a computer, and the crutch-lovers will use computers.

Richard.

 

[boulderjohn]

As for inputting the wrong EAN mix, that is something that can indeed happen. Counterintuitively, though, for recreational diving, the danger is not so much in exceeding MOD. People get the idea that if you exceed your MOD by a couple of feet for a couple of seconds, their lives are in danger. The margins are not cut that thin. In fact, it would really be hard for a recreational diver staying within recreational dive limits with any recreational nitrox mix to exceed the MOD by enough depth and time to have a toxing incident. It can happen, but not easily.

The greater danger is in exceeding NDLs because you have the wrong mix. If you are diving air and your computer thinks you are diving EANx 32, you can easily exceed limits to the point of getting DCS.

That really is something about which divers should be careful. After such an incident discussed here a number of years ago, I wrote to PADI and suggested that they add another word--instruments--to the predive check. That word would ensure that they have whatever means they are using to measure a dive (watch, bottom timer, or computer) on and ready to go. If using a computer with nitrox, they would check for the correct mix. PADI immediately wrote back that they agreed with me and were working on a new acronym to replace BWRAF. That was the last I heard, so they must have changed their minds.

But I made the change in my classes. I teach BWRAIF instead. The mnemonic I use is Bruce Willis Ruins Another Independent Film.

 

[Paladin]

For me, I simply do not trust a computer to always give me valid information. Any number of small, but significant, errors can be introduced due to malfunctions in the circuitry or programming. A single malfunctioning micro-transisitor will introduce a false 1 or 0 into the equation and, therefore, cause a false readout. It might be minor or significant, but it is there, nonetheless.

I am comfortable planning, and diving, my dives with tables. Not with computers. If one wants to let a computer do his thinking for him, fine, he can go for it. I prefer to do my own thinking.

As for how many divers are currently using computers over tables, I could not possibly care less how many others want to go the computer route. That's their problem. You will definitely see the tables being used if you dive with me or any of my usual dive buddies.