Info Why are tables not taught in OW classes anymore?

[ChrisDee]

The thread had been dormant for almost a month. If you think it should be ended, why did you restart it?

I'm not just being flippant. Your answer to my question, whatever it may be, is exactly why this thread continued on for so long.

Beginning of the season, statistically more divers entering the water.

609 posts, and still everyone miss's the point.

Everything computers and tables do, is try to fit the existing historical record of DCS onto a "Gaussian Curve" so that the tables and computers can estimate risk. Every-time anyone dives at the limits of a computer or the edges of a table, they put themselves closer to the actual cases of DCS, which is everything we are trying NOT to do. Everyone here, many inadvertently, are in fact promoting increased risk of DCS, thus ensuring this DCS issue is going to continue.

One of the biggest selling points of computers is to maximize the Calculus of a mathematical find the area of a curve by what is known as the Riemann sum. In English this means, from many dive computer marketing departments: "giving you more time underwater than a dive planned using a table."

You all are promoting blind acceptance of a "theory" and a "hypothesis" instead of teaching the: Who, What, Where, and Why of a thing. This is a big mistake.

This is the Gospel according to PADI, and basically many agencies worldwide:

"A dive computer provides the real-time dive information you need to dive well. A dive computer takes depth and time information and applies it to a decompression model to track the dissolved nitrogen in your body during a dive. Your computer continuously tells you how much dive time you safely have remaining."

Wrong! Your "safety" is the knowledge you have learned and how yo apply it. All things a computer can NOT do.

This is what DCS is: An individuals BMI, an individuals age, an individuals fitness, a individuals lung capacity, an individuals perfusion / diffusion, a individuals physiology, an individuals lipid cholesterol levels, a individuals medical history and prior disease issues, and then we have the environmental issues present on any individual dive, such as Temperature, intensity of the sun, water quality, environment, as far as workload, before during and after,...ETC, ETC, NONE of which a computer can measure or a table understand. This is where learning , and I am suggesting thoroughly learning all you can learn and all anyone can teach about a very important subject. Is this what is currently being done? (Rhetorical Question.)

And we come along and we attempt to simplify all of this by: "just buy a computer / follow the tables, or ask your instructor."

Stop thinking of Bubbles, and start thinking in terms of Diving gives you a Sunburn, (as time and knowledge have increased, it isn't just bubbles anymore folks,...) a minor sunburn that your body can generally easily recover from, most of the time. (This is a metaphor.) Think of ALL the factors that cause a Sunburn, at the cellular level, skin makeup, exposure times, sun intensity,....

And some dives will not be possible by using a table, but that isn't the point. The point is to understand the injury process, rather than blind reliance on computers, which debatable or not, which is what is happening. And as a result, the failure to teach AND understand the completeness of this whole subject, virtually ensures DCS is here to stay.

My humble opinion

 

[tursiops]

My humble opinion

...and totally off topic.
You should repost and start your own thread.

 

[boulderjohn]

Tables are not that hard to understand, especially the SSI tables, which is just “follow the arrows”. Knowing tables helps you to plan a dive, but unfortunately that is usually overlooked in OW classes too. Tables also help with figuring out how long your surface interval should be. Computers give you your surface time but most don’t tell you how long your surface interval should be before the next dive.

The overwhelming majority of dives today are multilevel, and if your dive is multilevel, a table cannot tell you what your surface interval should be, either, because it does not have an accurate pressure group for the previous dive. In most cases, the table will tell you that you violated decompression limits and have to wait until the next day to dive.

With a computer, after a surface interval after a multilevel dive, you can go to the planning mode and see how much time you will have at maximum planned depth for the next dive, and if you don't like what you see, you can wait a little longer. A table cannot do that, again, because it won't let you dive until the next day.

 

[boulderjohn]

You all are promoting blind acceptance of a "theory" and a "hypothesis" instead of teaching the: Who, What, Where, and Why of a thing. This is a big mistake.

I have no idea what this means.

The theories and hypotheses have been tested and retested over many decades. They are not things dreamed up last week.

If you wanted me as an instructor to instead teach the "Who, What, Where, and Why of a thing," I would first have to know what the Hell you are talking about. I know a heck of a lot about decompression theory, but if you were my boss and required me to teach the "Who, What, Where, and Why" of it, I wouldn't know where to start..

This is the Gospel according to PADI, and basically many agencies worldwide:

"A dive computer provides the real-time dive information you need to dive well. A dive computer takes depth and time information and applies it to a decompression model to track the dissolved nitrogen in your body during a dive. Your computer continuously tells you how much dive time you safely have remaining."

Wrong! Your "safety" is the knowledge you have learned and how yo apply it. All things a computer can NOT do.

Where can this safety knowledge be found? How do we apply that to our diving?

 

[lowwall]

Beginning of the season, statistically more divers entering the water.

609 posts, and still everyone miss's the point.

Everything computers and tables do, is try to fit the existing historical record of DCS onto a "Gaussian Curve" so that the tables and computers can estimate risk. Every-time anyone dives at the limits of a computer or the edges of a table, they put themselves closer to the actual cases of DCS, which is everything we are trying NOT to do. Everyone here, many inadvertently, are in fact promoting increased risk of DCS, thus ensuring this DCS issue is going to continue.

One of the biggest selling points of computers is to maximize the Calculus of a mathematical find the area of a curve by what is known as the Riemann sum. In English this means, from many dive computer marketing departments: "giving you more time underwater than a dive planned using a table."

You all are promoting blind acceptance of a "theory" and a "hypothesis" instead of teaching the: Who, What, Where, and Why of a thing. This is a big mistake.

This is the Gospel according to PADI, and basically many agencies worldwide:

"A dive computer provides the real-time dive information you need to dive well. A dive computer takes depth and time information and applies it to a decompression model to track the dissolved nitrogen in your body during a dive. Your computer continuously tells you how much dive time you safely have remaining."

Wrong! Your "safety" is the knowledge you have learned and how yo apply it. All things a computer can NOT do.

This is what DCS is: An individuals BMI, an individuals age, an individuals fitness, a individuals lung capacity, an individuals perfusion / diffusion, a individuals physiology, an individuals lipid cholesterol levels, a individuals medical history and prior disease issues, and then we have the environmental issues present on any individual dive, such as Temperature, intensity of the sun, water quality, environment, as far as workload, before during and after,...ETC, ETC, NONE of which a computer can measure or a table understand. This is where learning , and I am suggesting thoroughly learning all you can learn and all anyone can teach about a very important subject. Is this what is currently being done? (Rhetorical Question.)

And we come along and we attempt to simplify all of this by: "just buy a computer / follow the tables, or ask your instructor."

Stop thinking of Bubbles, and start thinking in terms of Diving gives you a Sunburn, (as time and knowledge have increased, it isn't just bubbles anymore folks,...) a minor sunburn that your body can generally easily recover from, most of the time. (This is a metaphor.) Think of ALL the factors that cause a Sunburn, at the cellular level, skin makeup, exposure times, sun intensity,....

And some dives will not be possible by using a table, but that isn't the point. The point is to understand the injury process, rather than blind reliance on computers, which debatable or not, which is what is happening. And as a result, the failure to teach AND understand the completeness of this whole subject, virtually ensures DCS is here to stay.

My humble opinion

I think you are saying that we should all be aware of personal factors that might increase our susceptibility to DCS.

OK. But how do you apply that? The only way I know of is to start with the tables or a computer and add a conservatism factor. There are multiple ways to do that, but you need to start with the baseline provided by the table or comp. You can't do it by feel.

 

[boulderjohn]

I think you are saying that we should all be aware of personal factors that might increase our susceptibility to DCS.

OK. But how do you apply that? The only way I know of is to start with the tables or a computer and add a conservatism factor. There are multiple ways to do that, but you need to start with the baseline provided by the table or comp. You can't do it by feel.

This is what DCS is: An individuals BMI, an individuals age, an individuals fitness, a individuals lung capacity, an individuals perfusion / diffusion, a individuals physiology, an individuals lipid cholesterol levels, a individuals medical history and prior disease issues, and then we have the environmental issues present on any individual dive, such as Temperature, intensity of the sun, water quality, environment, as far as workload, before during and after,...ETC, ETC, NONE of which a computer can measure or a table understand. This is where learning , and I am suggesting thoroughly learning all you can learn and all anyone can teach about a very important subject. Is this what is currently being done? (Rhetorical Question.)

Assuming Lowwall is correct, I will answer your rhetorical question as best I can.

The OW course does indeed teach students that there are certain known factors that influence DCS, including obesity, age, fitness, and temperature. Students are indeed taught to approach no decompression limits with those thoughts in mind.

I will admit, however, that I shamefully never taught students how to adjust for most of the items on your list. In fact, if I were to go back to teaching, I would not even know how to teach students to take into account lung capacity, individual perfusion, individual diffusion, individual lipid cholesterol levels, sun intensity, water quality, and environment. Perhaps you would be so kind as to provide the resources that will tell us, for example, the effect of lipid cholesterol levels on diving so we know what to teach about it.

You can also tell us how taking those factors into account differs between using a computer and using tables.

 

[boulderjohn]

I will admit, however, that I shamefully never taught students how to adjust for most of the items on your list. In fact, if I were to go back to teaching, I would not even know how to teach students to take into account ..., individual perfusion,

I realized after I posted this that I did teach tech students to take individual perfusion into account. During the working part of a dive perfusion is usually greater than during decompression stops, meaning that the diver's perfusion rates are greater during on-gassing than during off-gassing. Accordingly, I taught them to eschew the usual ideal of the motionless decompression stop and instead engage in mild exercise to increase the off-gassing perfusion rate.

I don't believe this will normally be a significant factor in an NDL dive because of that comparatively short ascent profile.

 

[The Chairman]

This thread, and others like it will be resurrected from time to time as long as we're on the web. Zombies are real.

Diving is a passionate sport. Many older divers and instructors equate the seeming difficulty of learning tables as coming to understand the science of the physiology involved. It's not. They often see the elimination of tables as the dumbing down of their sport. They struggled to enter the sport, then why shouldn't everyone suffer?

Rather than being "dumbed down", it's my somewhat unpopular opinion that scuba instruction is simply being modernized. I own a Cosori "smart" air fryer. It can talk to my phone and can do wonderful things... but only if I understand the cooking process. One of my friends sent me a pic of a meal she burned in hers. Le sigh. Misapplying the tech, just like misusing the tables can result in being hurt. You still should endeavor to understand the physiology behind what you're doing as well as how to operate the tech in question.

Sure, there will be those who are offended by tables, or someone else's desire to retain tables that will keep this thread alive for a long, long time. That's OK. Let them pontificate! Viva zombie threads!

 

[Jcp2]

This thread, and others like it will be resurrected from time to time as long as we're on the web. Zombies are real.

Diving is a passionate sport. Many older divers and instructors equate the seeming difficulty of learning tables as coming to understand the science of the physiology involved. It's not. They often see the elimination of tables as the dumbing down of their sport. They struggled to enter the sport, then why shouldn't everyone suffer?

Rather than being "dumbed down", it's my somewhat unpopular opinion that scuba instruction is simply being modernized. I own a Cosori "smart" air fryer. It can talk to my phone and can do wonderful things... but only if I understand the cooking process. One of my friends sent me a pic of a meal she burned in hers. Le sigh. Misapplying the tech, just like misusing the tables can result in being hurt. You still should endeavor to understand the physiology behind what you're doing as well as how to operate the tech in question.

Sure, there will be those who are offended by tables, or someone else's desire to retain tables that will keep this thread alive for a long, long time. That's OK. Let them pontificate! Viva zombie threads!

This won’t be the last of us.

 

[Belzelbub]

Diving is a passionate sport. Many older divers and instructors equate the seeming difficulty of learning tables as coming to understand the science of the physiology involved. It's not. They often see the elimination of tables as the dumbing down of their sport. They struggled to enter the sport, then why shouldn't everyone suffer?

Rather than being "dumbed down", it's my somewhat unpopular opinion that scuba instruction is simply being modernized.

That's a good way to put it. I didn't exactly struggle learning tables, but I know that many in my early classes did.

At the time that I was first learning, tables were the way that most people managed their dives. They'd use it to know how long they might be able to stay down on each dive. Computers existed, but the majority of divers didn't own one. They were expensive, and reliability hadn't yet been proven.

Today, that's not the case. Most divers will use a computer on their dives today. Reliability has been pretty well shown. Some practices have changed, but computers are going to be used by most divers for the foreseeable future. If they hadn't proven reliable, we wouldn't see so many dive computers, and so few tables today.

Given that the vast majority of divers today are going to be using computers, teaching just tables is going to be doing them a disservice. At the end of a dive, no one cares what pressure group you are in. They may want to know what your NDL will be for the next dive in 45 minutes. That can be done by either checking the computer, or checking a table. One method will be expected on a dive boat, another method will most likely raise the eyebrows of your fellow divers.

As I said earlier, tables and computers are tools. There is undoubtedly a problem, as shown by stories here, of divers not knowing how to work their computers, and subsequently locking them out. But, probably not a bigger problem than divers not knowing how to work their tables. At least with the computers, they'll know something is wrong.