PADI tables finally going away?

[boulderjohn]

I thought I had given the examples. But, let me try to rephrase it, ...)

I read your response as carefully as I could, trying my best to understand your points. I think we have a problem in that English is not your first language, so perhaps you are not phrasing your responses to best advantage.

I have finally decided that, to put it as politely as I can, you are drawing conclusions based upon an incomplete understanding of the theory behind ascent rates and decompression. To put it bluntly, I don't think you understood what you wrote about in your response. It really doesn't make sense to me. You are presenting opinions here that I have never seen presented anywhere, and I have done a lot of reading on this subject.

As you said at the end of your post, you are still pretty early in your education in these matters.

I guess I am many years away from decompression dive, one step after the other and let's make them baby ones. =)

Some of the people who have been disagreeing with you have a lot of experience and have done a lot of studying of decompression theory.They have gone well beyond the baby steps you say you are taking. With that in mind, I have to have a great deal of admiration for your self confidence. If I were early in my understanding of a complex theory, and if people who really knew a lot about it were telling me I was completely wrong about what I understood, I would not have the courage to tell them that they were wrong and I was right. You obviously have more confidence in yourself than I would have ever had at that stage in my learning.

On the other hand, if you ever want to progress beyond baby steps, it might be wise to listen to people who have gone beyond those steps rather than lecture them about why they are wrong about everything.

 

[riana]

I think that every diver should be able to continue diving if a computer fails. I use a computer and a bottom timer with a set of tables on every dive I do. To not teach students how to save their dive or vacation with tables is a shame. And shame on so many people for wanting to take a short cut and get rid of them. It does not take long to teach them and I have had a failure so I know having a back up system is always prudent.

 

[Quero]

In thinking about the replies to this thread in support of teaching tables to OW students, it seems to me that they fall into three categories:
1) The "it's important in principle" reasons, i.e., people should have a solid understanding of decompression theory before using a dive computer, and tables are instrumental in learning that theory.
2) The "we shouldn't ask people to use unnecessary equipment" reasons, i.e., not all divers have access to dive computers, and so all divers must be instructed in an alternative low-tech method of dive planning, just in case they wind up in a situation in which there's no computer for them to use.
3) The "I paid good money for this dive trip and I don't want to miss the next dive" reasons, i.e., what if my computer fails and I want to keep diving?

The response to the first category of reasons that most appeals to me is something like, It's not necessary to understand how an internal combustion engine works in order to safely operate an automobile. Decompression theory is fascinating, but I think a general understanding of it is sufficient for open water students, and further, I think the same level of understanding is needed whether learning to plan dives with tables or with a computer. For those who want more, there are books like Deco for Divers that lay the theory out in non-technical terms without any reference to dive tables.

The response to the second category of reasons that most appeals to me is that we should be teaching what students need. If we are teaching students who have limited or no access to dive computers, then of course we need to teach tables, but if we are teaching students who already own/plan to purchase dive computers or who intend to rent computers for their dives, I see no reason to force them to study table use. We should be teaching what students need and are most likely to use, not what some well-intentioned but misguided it's-important-in-principle view mandates.

In response to the third category of reasons, this is where it gets really muddy. Assuming a dive computer fails during a multi-level dive and assuming there is a set of tables accessible to the diver, and assuming the diver has the data from the previous dive(s), yes, s/he could try to plan a subsequent dive using the tables. However, in my experience here, many, if not most, of our multi-level dives that are perfectly okay on a computer violate the NDL on a table. This violation will prevent the diver from doing any subsequent dive anyway, if the table rules are adhered to. So even knowing how to use the tables won't help in most cases, unless the diver has conscientiously tracked average depth throughout the previous dive(s) and can use a rule of thumb, like the 120 rule, as a way to interpolate the data and apply it to planning the next dive according to the tables. For most people, diving is a recreational pursuit. As such it's not worth risking one's physical well-being just to avoid missing a dive. When a computer fails, just sit the next dive or two out. It's the prudent thing to do in the same way that skipping a dive day when you're congested rather than stuffing yourself with decongestants is the prudent thing to do. Yes, some people will try to dive anyway by self-medicating when they've got a cold, and some people will try to do a dive using another means of dive planning after a computer failure. But just because some people do it does not make it advisable.

 

[Nikki McAllen]

I took my PADI Divemaster course at age 50 after nearly 40 years of recreational diving (yes, naui age ten). I was outraged that PADI made me submit to all that wheel training and tables with performance evaluation.

Mostly irritated by the wheel. Was nearly impossible to read without major magnification at my age, but most humiliating was they kept saying: "its going away soon" in favor of the ERDPML. Well I had to buy one regardless, and demonstrate proficiency. I also had to buy an ERDP which failed at the first drip of water from a sweaty beer. What a ripoff ! A joke for planning the ERDP is like 1980's computer tech and we all know it.

PADI should use the tables as a teaching aid then drop the whole thing and allow divers to find their own way in the world. Divers do this anyway. The majority rely on guides and computers almost entirely for diving with NO prior planning. They simply go shallower if the computer says they should. Sad but true.

There are better options for rec and tec divers to plan their dives. Check out iScuba Plan on the iPhone. It's a dream. PADI can never touch this, they shouldn't even try. There's even a version for Tech Diving. Each program costs under $10. I'd send a snap but don't feel like hosting the photo for scubaboard.

iScuba Plan for iPhone, iPod touch, and iPad on the iTunes App Store

If anyone is offended by my title criticism consider that PADI just recently updated the Divemaster Program for the first time in fifteen years ! I think that's unconscionable and embarrassing for anyone holding the card. This negligence caused me to decline the IDC program in favor of any other certifying agency the moment I heard. I was actually on-site in Thailand ready to go. Costly mistake.

 

[Puffer Fish]

I think you are worrying about the theory more that what will actually happen. I dive all the time with someone using a Suunto, Yes the model is different. Yes the accent profile effect is a bit different. But because the bottom time is slightly less with the Suunto, the effect is that, if you follow the more conservative Suunto, is you both end up very close to each other. In several hundred dives, have not seen any issue.

If one tried doing a long deco dive, yea, there would be issues.. but that is a subject for a different area.

Regarding who is right in this, Suunto would get my vote, as they are attempting to reduce the formation of micro bubbles (which are most likely not that huge of a concern, except that you have to have micro bubbles before you go to getting really bad big bubbles). Theirs is based on actual testing, not some guess as to what was best.

You do raise a very interesting issue though....involving teaching tables...it tends to accidentally teach a dogma, rather than an ever changing science. I don't think that was intended, but teaching hard numbers tends to produce that effect in a lot of people. (note: I was taught the classic 60 ft = 60 minutes, and 60 ft per minute maximum ascent rate, and not safety stop, should I still be using that today?)

If you look closely on the algorithm I mentioned you will see that it is exactly what happens, the way you ascend for the Suunto is different from the traditional. There are other cases for example, there are instances were the computer credit you for doing a stop at mid max depth and then other at 5m while others consider the stop at mid max depth as being on gassing, those computers would disagree on the ascend schedule and the mid stop one disagree with the regular procedure taught in OW courses.

 

[AfterDark]

puffer fish
(note: I was taught the classic 60 ft = 60 minutes, and 60 ft per minute maximum ascent rate, and no safety stop, should I still be using that today?)

Did you take any hits using it? I never did. I do believe as we age it's probably best to use 30-60. I've always added 2-5 mins to the required time at the last shallow stop, deco not saftey. I do know if my life some how depended on getting to the surface quick during a NDL dive I'd do the 60-60 without a SS without fear,well much anyway.

 

[Brendon]

Quero

In thinking about the replies to this thread in support of teaching tables to OW students, it seems to me that they fall into three categories:
1) The "it's important in principle" reasons, i.e., people should have a solid understanding of decompression theory before using a dive computer, and tables are instrumental in learning that theory.

PADI Dive tables have nothing to do with "Decompression Theory". Thats like saying, I need to eat the McDonald's cheeseburger wrapper to learn how many calories are in the burger.

The response to the first category of reasons that most appeals to me is something like, It's not necessary to understand how an internal combustion engine works in order to safely operate an automobile. Decompression theory is fascinating, but I think a general understanding of it is sufficient for open water students, and further, I think the same level of understanding is needed whether learning to plan dives with tables or with a computer. For those who want more, there are books like Deco for Divers that lay the theory out in non-technical terms without any reference to dive tables.

Learning dive tables are like learning to use a measuring cup, Not how to cook... Your not teaching theory when instructing how to use tables... Your showing them a flow chart, thats it..

The response to the second category of reasons that most appeals to me is that we should be teaching what students need. If we are teaching students who have limited or no access to dive computers, then of course we need to teach tables, but if we are teaching students who already own/plan to purchase dive computers or who intend to rent computers for their dives, I see no reason to force them to study table use. We should be teaching what students need and are most likely to use, not what some well-intentioned but misguided it's-important-in-principle view mandates

.

Most of us have been trained at some point how to use or teach dive tables. So why after all this time replace one with another and not just include both. There are advantages to both. Tables aren't rocket science neither are computers to include both really doesn't add much time to your class . Run them congruent and stop to show the differences. I think those who complain about it taking more time, just need more practice... Besides I think for alot of instructors its about time to start doing something extra for your students and not the minimum.

In response to the third category of reasons, this is where it gets really muddy. Assuming a dive computer fails during a multi-level dive and assuming there is a set of tables accessible to the diver, and assuming the diver has the data from the previous dive(s), yes, s/he could try to plan a subsequent dive using the tables. However, in my experience here, many, if not most, of our multi-level dives that are perfectly okay on a computer violate the NDL on a table.

What? Multi-level dive.... It stops being a multi-level dive when your computer fails. Now it is deepest depth and total bottom time, now go figure your next dive. If you can do it great if not increase SI. Most people should be able to remember the last 24 hrs of diving, so figuring in your other dives really isn't that complicated... If concerned err on the side of caution and increase your end of dive letter group by 1 or 2... Your tact here seems to be to scare someone into thinking that if your computer fails it is then to dangerous to return to that 40-60 reef using dive tables... Thats ridiculous.

 

[Blackwood]

. Yes, some people will try to dive anyway by self-medicating when they've got a cold,.

I did that last weekend. Racked up 57 minutes of surface swimming (2/3 of which was against an obnoxious current) for about 2 minutes in midwater between the surface and 12 feet trying to equalize.

Good times.

 

[Quero]

Brendon, you're reading too fast. If you go back to my post, you will see that I'm not saying that my views are those three I listed at the top, but instead that this is my analysis of the responses of those posters who advocate strongly that tables must be taught. Therefore, a lot of your response to my post is way off target, to put it nicely.

As to your last paragraph, just go run the numbers, and you'll see that what I'm saying has merit and is not, as you claim "ridiculous." Let me illustrate it for you:

If a diver has done, for example, a multilevel dive to a maximum depth of 80 fsw without coming anywhere near the NDL as indicated by his dive computer, and then 35 minutes into the dive his computer dies, according to the PADI table (since this thread concerns PADI tables) he has already exceeded the 30 minute NDL for that dive, and furthermore, since he has exceeded the NDL by "only" 5 minutes, he must perform an 8-minute deco stop before surfacing and then stay out of the water for 6 hours. I don't know how the charters run where you dive, but here, if a diver has to stay out for at least 6 hours, the diver misses the next dive (yes, even if it is a dive to a 40-60 foot reef), and most likely all subsequent dives on that day.

Now, let's take it a little further and say that the diver's computer fails on the second dive of a three-tank trip. The first dive was to a maximum depth of 80 fsw for 30 minutes (to keep things within the NDL), and that he then ends up in pressure group R. After a standard 1 hour SI, he's now in F. His next dive has a max depth of 70 fsw, and he starts out with an RNT of 16 minutes. Then, curses, his computer fails when he's 35 minutes into the dive. Yikes! He's now a whopping 11 minutes over his NDL, and table rules require a 15 minute deco stop plus 24 hours out of the water. That's not just the next dive scratched today, but tomorrow's dives too!

The only conceivable way in these kinds of scenarios--which are actually quite benign dives here where I work--to avoid this outcome while using PADI tables would be to perform an average depth calculation and apply that to finding a pressure group. This is why I said that the third category of reasons, not wanting to miss a dive and therefore planning with a table after a computer failure, is not workable in many, many instances, and in fact would not be workable in the vast majority of dives we do here.

 

[Quero]

I did that last weekend. Racked up 57 minutes of surface swimming (2/3 of which was against an obnoxious current) for about 2 minutes in midwater between the surface and 12 feet trying to equalize.

Good times.

I know. Sometimes I just have to swallow those pills and try--it's different when you're having to work and you wake up sick--but I always pay the price. The cold takes three times longer to go away, I end up with a sinus infection, and i have to pass my students off to somebody else, so I lose income. I'd rather miss a dive due to a computer failure!