Info Why are tables not taught in OW classes anymore?

[TMHeimer]

If you're ever in Albuquerque, I'm extending an open invitation for you to come teach dive tables in under 10 minutes.

I'm not trying to be an ass, and I'm sure you think you can do that, but you are underestimating the time it takes to teach them, because you haven't ever taught them, by a factor of probably 20.

When I taught them, initially, I followed our shop's standard powerpoint, and taught them at the end of the course. That was super painful for everyone, because it was day 2 of classroom and no one wanted to be there, and I was presenting the densest, most hard to grok, material.

Later I switched to teaching the tables first. The students didn't understand anything (they'd retained about 10% of what they'd read in PADI's book). I'd preface the beginning of the course with a disclaimer: "I'm going to teach you things that you probably aren't going to understand, or see the reason for, right now. But, by tomorrow, you'll see why we are doing this."

That improved test performance (teaching RDP upfront) but it didn't improve retention. I was solely teaching to the test, and I was re-teaching that material, albeit faster, two weeks later because it had all been lost.

I believe what you say. I think what johndiver999 may be saying is that tables probably aren't hard to teach if the students have really studied the book (e-learning now) a lot. I had no problem learning them and that's the sort of thing that drives me crazy, but... I studied it well beforehand. Now, since you said the student's retained about 10% of what they read in the book this may indicate they read the tables part over once? I was sitting in on a couple of classes as a DM and observied the instructor teaching tables. Went pretty well-- maybe the students studied.

 

[tursiops]

I followed our shop's standard powerpoint,

I've never taught the tables using powerpoint. That's like showing of video of someone cooking. Cooking, and tables, are a hands-on activity. You learn by doing, not by watching or reading.

 

[johndiver999]

If you're ever in Albuquerque, I'm extending an open invitation for you to come teach dive tables in under 10 minutes.

I'm not trying to be an ass, and I'm sure you think you can do that, but you are underestimating the time it takes to teach them, because you haven't ever taught them, by a factor of probably 20.

When I taught them, initially, I followed our shop's standard powerpoint, and taught them at the end of the course. That was super painful for everyone, because it was day 2 of classroom and no one wanted to be there, and I was presenting the densest, most hard to grok, material.

Later I switched to teaching the tables first. The students didn't understand anything (they'd retained about 10% of what they'd read in PADI's book). I'd preface the beginning of the course with a disclaimer: "I'm going to teach you things that you probably aren't going to understand, or see the reason for, right now. But, by tomorrow, you'll see why we are doing this."

That improved test performance (teaching RDP upfront) but it didn't improve retention. I was solely teaching to the test, and I was re-teaching that material, albeit faster, two weeks later because it had all been lost.

LOL, it is not a problem at all. I would be willing to make a sizable wager as well that I could accomplish the goal in the stated time period.

However, I suggest you carefully read my description of the students and pay particular attention to the descriptor I used with respect to them. Of course, I will be the arbiter of "smart".

In all seriousness, I think it may make sense to spend a few minutes discussing the tables simply because they depict the relevant physiological issues in a tabular form. Whether the students are exposed to how to back calculate the required surface interval for a proposed NDL repetitive dive is irrelevant and outside of the scope of an orientation. As I said the issue is trivial.

The whole idea is simply that if you dive deeper, your dive is shorter AND the longer and deeper your previous dive, the longer you have to "rest" on the surface to recover, before another dive.

Sorta like lifting weights: if you lift heavy weights many times it will take longer to recover than if you lifted light weights a few times. A very simplistic concept.

I would not argue that students need to actually learn to use tables to plan dives or that it would necessarily be beneficial as a practical matter.

It is appropriate to allow computers to supplant tables for actual recreational diving activities because they give valuable feedback on depth, time, remaining NDL and ascent rate - in real time. If the student can not learn to collect and interpret those data from their computer, then they have bad eyes or the computer is poorly designed and/or the student is stupid.

 

[BRT]

Sharing a computer is NOT a Best Practice. It probably doesn't make a lot of difference on a single dive, but the differences accumulate after several dives.
I would not like a dive center that made that suggestion. I would rather see them rent a computer to someone.
If I were handed an instabuddy with no computer, I would tell the dive center No, unless the instabuddy is willing to restrict his dive to table depth/times, e.g. 30 mins for an 80 ft max dive.
"Average" depth on a dive is not relevant; on-gassing and off-gassing are not linear with depth, so an '"average" is of no value in estimating nitrogen status. For example, the NDL for 80 ft is 30 mins, but the NDL for 40 ft is 140 mins. No relationship. And even if you do it as average pressure, instead of average depth, it doesn't work.

I am just finishing up a 5 week dive trip. I carry 2 identical computers, one in a console and one in a wrist mount attached to the HP hose. The one in the wrist mount reads about 1 foot per 25 feet deeper than the one in the console. Reads 78 feet when the console mount and my wife's and another computer read 75 feet. It is fairly astounding how much difference that makes over 2 dives. At the end of the second dive of one day the one that reads deeper was 6 minutes into deco while the one that I believe to be correct had 15 minutes of no deco time remaining. It wouldn't be too hard for one buddy to hang consistently below the other buddy and be in deco even though the buddies computer was well clear of deco.

 

[tursiops]

I am just finishing up a 5 week dive trip. I carry 2 identical computers, one in a console and one in a wrist mount attached to the HP hose. The one in the wrist mount reads about 1 foot per 25 feet deeper than the one in the console. Reads 78 feet when the console mount and my wife's and another computer read 75 feet. It is fairly astounding how much difference that makes over 2 dives. At the end of the second dive of one day the one that reads deeper was 6 minutes into deco while the one that I believe to be correct had 15 minutes of no deco time remaining. It wouldn't be too hard for one buddy to hang consistently below the other buddy and be in deco even though the buddies computer was well clear of deco.

Interesting.
Your post makes me wonder if one is set on salt water and one on fresh water.
I'd except some NDL differences, but not as much as you got.
Your computers aren't Suuntos, are they? Notable pressure sensor issues.

 

[BRT]

Interesting.
Your post makes me wonder if one is set on salt water and one on fresh water.
I'd except some NDL differences, but not as much as you got.
Your computers aren't Suuntos, are they? Notable pressure sensor issues.

Oceanic Veo 250's. I don't believe there is any way to manually set them to FFW. DIving them above 2000 feet will make them measure in FFW.

 

[VikingDives]

I've never taught the tables using powerpoint. That's like showing of video of someone cooking. Cooking, and tables, are a hands-on activity. You learn by doing, not by watching or reading.

I didn't either. I should have said progression, not powerpoint.

 

[VikingDives]

LOL, it is not a problem at all. I would be willing to make a sizable wager as well that I could accomplish the goal in the stated time period.

However, I suggest you carefully read my description of the students and pay particular attention to the descriptor I used with respect to them. Of course, I will be the arbiter of "smart".

In all seriousness, I think it may make sense to spend a few minutes discussing the tables simply because they depict the relevant physiological issues in a tabular form. Whether the students are exposed to how to back calculate the required surface interval for a proposed NDL repetitive dive is irrelevant and outside of the scope of an orientation. As I said the issue is trivial.

The whole idea is simply that if you dive deeper, your dive is shorter AND the longer and deeper your previous dive, the longer you have to "rest" on the surface to recover, before another dive.

Sorta like lifting weights: if you lift heavy weights many times it will take longer to recover than if you lifted light weights a few times. A very simplistic concept.

I would not argue that students need to actually learn to use tables to plan dives or that it would necessarily be beneficial as a practical matter.

It is appropriate to allow computers to supplant tables for actual recreational diving activities because they give valuable feedback on depth, time, remaining NDL and ascent rate - in real time. If the student can not learn to collect and interpret those data from their computer, then they have bad eyes or the computer is poorly designed and/or the student is stupid.

Exposure to the concepts isn't, I'd venture, what instructors think of when you say teaching the tables. We are thinking of teaching to the point where the student can use the tables to get the correct answer for scenarios and/or pass the test.

I use the tables to expose my students to concepts like doing the deepest dive first... Tables aren't the greatest tool for that, but it's a way to communicate concepts. They are also a great way to extract pained looks from students when you explain how have to teach them to use the tables to calculate their dives.

 

[cgblake]

I'm glad I was taught the tables, even though most of my dive buddies have computers I still reference the tables, get a planned depth and set my watch on a countdown of that max depth and max time for a plan. Only problem with that is I don't have as much bottom time as I could going to a couple different depths but I could get a laminated tables or something to bring with me if I was concerned about that. Right now I'm more concerned about building my skills better.

 

[Lorenzoid]

I'm glad I was taught the tables, even though most of my dive buddies have computers I still reference the tables, get a planned depth and set my watch on a countdown of that max depth and max time for a plan. Only problem with that is I don't have as much bottom time as I could going to a couple different depths but I could get a laminated tables or something to bring with me if I was concerned about that. Right now I'm more concerned about building my skills better.

If you're having fun with tables, then by all means keep having fun. But you can do the exact same thing using the dive planning function that most computers provide: you enter a single planned depth, and the computer gives you the corresponding time limit.