PADI tables finally going away?

[ctx120]

Devon Diver "The rudimentary tests used on AOW/Deep courses to test for narcosis really don't cover every subtle aspect of it. And, definitely, how you feel is never going to be an accurate test for it..."


During my test we were given a master lock to open , remembering the combination at 100 ft was easy .but reading the numbers with-out my reading glasses was difficult

 

[The Chairman]

I can see by you resorting to insults and personal attacks with clever one liners this debate has gone south and not really worth my time to continue.

No insults or personal attacks here: I just refuse to dive with people who demonstrate a high level of denial. It's the truth and nothing but the truth. I won't dive with anyone who denies they are narced below 80 fsw. Your arrogance and/or denial make you a less than ideal buddy.

while I was suffering from surface narcosis

Get over yourself. You blatantly distorted what I was saying and I called you on it. Rather than admit you made a mistake, you cowardly hide behind me hurting your feelings? Yet another attempt at denial. I am not impressed.

You have yourself a great day there Net Doc, and enjoy your computer!

I did. It crapped out on me today during deco with six minutes left. Somehow I survived the trauma. Perhaps it was my training. Perhaps it was just dumb luck. Probably it was a mixture of both. Either way, I survived with no hints of DCS and we celebrated a wonderful dive in Hudson Grotto by doing an introspective debriefing, laughing at ourselves, having dinner at Mykonos in Tarpon Springs and then reveling the rest of the night away at Howl at the Moon in Orlando. While I was there, I saw a lot of people who thought they were not drunk even though they were making some terrible decisions. They certainly reminded me of people who think they never get narced. No, I didn't let them drive me home either!

I can sugar coat a lot of things in this world. Ask me if your butt looks fat in a wet suit, and I will be kind. Ask me what I think of your singing, and I will do my best to endure it. But describe to me how unsafe you are, and be prepared for me to be BLUNT and a tad abrasive. Sure, I might hurt your precious feelings, but hopefully I will make you think the next time you descend below 80 FSW. You can do it. You can even go to 250 fsw! But don't deceive yourself into believing that you can think nearly as fast or as comprehensively as you do on the surface. That's just stupid talk designed to wash the decks down with testosterone. Who needs it? Not me!

 

[The Chairman]

Are you saying to do a 115 foot dive followed by a say 90 footer I would not be allowed to do it if I showed up with my bottom timer and an analog depth gauge and watch for back up?

Actually Jim,

NO ONE suggested that at all, but thanks for the dramatic stand!!! Some did suggest that instructors be given the option of teaching only tables. No one is trying to take anyone's tables from them. There just seem to be a number of us who want to teach students how to use the tools they will be diving with and there are others who see tables as some sort of sacred cow: the holy grail of diving edumacation.

So far it has been asserted against this notion of using computers:

• Instructors are not professionals
• Narcosis is a myth
• If your computer craps out, you will surely die
• Tables are math
• Tables are the only way to learn physiology
• Students who don't learn tables will surely die

Tongue in cheek? Perhaps. There are just so many myths out there about tables, computers and their relationship to learning. So far, no one (not even I) has produced any studies. All we have is some anecdotal evidence pulled from our experiences and possibly our butts. It's up to each of us to make our decisions by what we feel comfortable with. No more and certainly no less.

 

[Eric Sedletzky]

No insults or personal attacks here: I just refuse to dive with people who demonstrate a high level of denial. It's the truth and nothing but the truth. I won't dive with anyone who denies they are narced below 80 fsw. Your arrogance and/or denial make you a less than ideal buddy. Get over yourself. You blatantly distorted what I was saying and I called you on it. Rather than admit you made a mistake, you cowardly hide behind me hurting your feelings? Yet another attempt at denial. I am not impressed. I did. It crapped out on me today during deco with six minutes left. Somehow I survived the trauma. Perhaps it was my training. Perhaps it was just dumb luck. Probably it was a mixture of both. Either way, I survived with no hints of DCS and we celebrated a wonderful dive in Hudson Grotto by doing an introspective debriefing, laughing at ourselves, having dinner at Mykonos in Tarpon Springs and then reveling the rest of the night away at Howl at the Moon in Orlando. While I was there, I saw a lot of people who thought they were not drunk even though they were making some terrible decisions. They certainly reminded me of people who think they never get narced. No, I didn't let them drive me home either!

I can sugar coat a lot of things in this world. Ask me if your butt looks fat in a wet suit, and I will be kind. Ask me what I think of your singing, and I will do my best to endure it. But describe to me how unsafe you are, and be prepared for me to be BLUNT and a tad abrasive. Sure, I might hurt your precious feelings, but hopefully I will make you think the next time you descend below 80 FSW. You can do it. You can even go to 250 fsw! But don't deceive yourself into believing that you can think nearly as fast or as comprehensively as you do on the surface. That's just stupid talk designed to wash the decks down with testosterone. Who needs it? Not me!

Calling me deluded and suffering surface narcosis sure sounds to me like an insult, not that I really care. I've been called worse. I just find it interesting.

So then I guess you're qualified to tell people you've never met or know what their individual tolerance level is to narcosis? You're also saying that everybody begins to get narced at at 80 feet wether they think so or not.
I think you're wrong.
Believe me there are no feelings hurt here whatsoever. You accuse me of arrogance and ego, actually my friend I see the same in you with your bellowing about how you're going to be blunt and don't expect anything sugar coated, blah, blah, blah, give me a break. Save it for someone else. Believe me, I've been narced hard, I know what it is. I also know at what depths I can still function,.I stay away from the depthsd that I know will be a problem.
Doing an air dive to 250 feet? Maybe your buddy there from the Phillipines that you thanked can do it and claim he felt fine but to me that is pure idiocy. I wasn't going to tell him that because it's none of my business. There's no denial here, I know where my numbers are and I don't deny it. But I think you're going a bit overboard telling me I'm in denial about my own narcosis tolerance level. You don't even know me.

I don't think you have to worry about us ever divinbg together. I dive on the North Coast of California in 42 to 50 degree water year around with big surf, ripping currents, and lot's of big fish with big teeth. I wear enough neoprene to make 4 suits where you're from. (There, how's that for ego eh?)
I doubt you'll evert come here, and I doubt I will ever go there. Actually I don't have the slightest bit of interest.

Have fun self inflicting some surface narcosis at Howl at the Moon. Have one for me.

 

[dschonbrun]

Pete "NetDoc"... think we need to soften this conversation. Lot's of strong personalities and opinions.

Below 80 fsw, most people experience some kind of mental deficiency due to narcosis. This percentage increases below 100 fsw. The effects vary dramatically based on several factors including environment, duration, pre-dive conditions, and individual physiology.

Computers are built off of table based information. My opinion is that divers should learn the theory and start with tables (simple) and then move swiftly to a computer as it is more accurate for predicting actual absorbed oxygen and nitrogen levels. And though I use computers on the dive, I do my dive plans using tables, which come down with me on a tick sheet.

People can dive safely on both tables and computers. Let them learn both and make an educated choice on how they want to enjoy the sport. I dislike divers and instructors who strongly tell people what kit to use and how to set it up. I prefer providing guidance and educating an individual and then letting them make their own choices about kit and about diving approach.

Rec BCD vs BP/W
Steel vs Aluminum
Back vs Side-mount
Tables vs Computer
SPG vs Air Integrated Computer
Wetsuit vs Dry-Suit

All of the choices are complex and require knowledge... provide people with facts, and let them make their own choices.

D

 

[DevonDiver]

Hi David,

I think it is the use of the word 'experience' (as in "most people experience...") that causes the biggest misunderstanding about narcosis.

People read the word 'experience' and translate that to mean 'percieve' or 'notice' or 'register'.

Everyone experiences narcosis physiologically, but may not register it consiously.

Being unaware that narcosis is degrading your performance is the norm. Feeling obvious signs of narcosis is definitely less common.

I don't think it is a case that conditions increase or decrease the effects of narcosis, so much as they highight or mask the effect that you are suffering. Partial pressure of nitrogen causes narcosis... bad viz doesn't. However, bad viz can be the psychological trigger (stressor) that brings your narcosis 'out into the open'.

From my experience, narcosis can be present, but unnoticed. A dive can go like clockwork and you feel fine. Muscle memory, ingrained skills and pre-planning get you through just fine. However, a slight deviation from the norm, a stressor or an emergency situation can quickly expose the narcosis that was previously unnoticed.

 

[The Chairman]

Calling me deluded and suffering surface narcosis sure sounds to me like an insult, not that I really care. I've been called worse. I just find it interesting.

It's an observation based on my comprehension of narcosis and self deception. The "surface narcosis" comment was facetious... don't read more into it and feign indignation. You still never admitted or denied to misrepresenting what I said.

So then I guess you're qualified to tell people you've never met or know what their individual tolerance level is to narcosis?

I am quite qualified to determine who I'll dive with. You don't fit the profile. I don't care how much neoprene you wear. Under 80 fsw you are narced. If you can't accept that, then I won't accept you as a buddy. Pretty simple. You know what? I even teach my students to avoid buddying up with anyone who denies narcosis.

But the real point of this is NOT the efficacy of tables vs computers on any particular dive: it's about teaching students how to use them and what to do when they do crap out. There is no need to "dumb down" the curricula, but there is a need to help them understand the limits and foibles of whatever they use. Unless you are teaching your students how to derive their own tables from the research at hand, there is simply no benefit of understanding derived from their use in my eye. In fact, there are lots of web based and computer based apps out there that do a WONDERFUL job of showing how N₂ loads and unloads from your body.

 

[Jim Lapenta]

Actually Jim,

NO ONE suggested that at all, but thanks for the dramatic stand!!! Some did suggest that instructors be given the option of teaching only tables. No one is trying to take anyone's tables from them. There just seem to be a number of us who want to teach students how to use the tools they will be diving with and there are others who see tables as some sort of sacred cow: the holy grail of diving edumacation.

So far it has been asserted against this notion of using computers:

• Instructors are not professionals
• Narcosis is a myth
• If your computer craps out, you will surely die
• Tables are math
• Tables are the only way to learn physiology
• Students who don't learn tables will surely die

Tongue in cheek? Perhaps. There are just so many myths out there about tables, computers and their relationship to learning. So far, no one (not even I) has produced any studies. All we have is some anecdotal evidence pulled from our experiences and possibly our butts. It's up to each of us to make our decisions by what we feel comfortable with. No more and certainly no less.

Actually Pete, He did. Right here. dschonbrun in the post before mine:

"For professionals and charters... we usually set a time and depth limit for the dive... providing a level of conservatism. In groups, we offer divers on computers 10 minutes extentions to the overal Bottom Time planned. For divers we know and trust, they can stay down as long as they like on unguided dives as long as they have their own computer and have proven they are competent with it."

This seems to say that if I show up with my BT and tables or my Wheel(yep have it and still use it for planning) and watch and analog gauge that I won't be allowed to do the dive or at least plan it and dive that plan on my own. (Cause if I don't know who I'm diving with I'm planning it as a solo dive.)

And I will continue to teach tables as SEI requires it along with Deco to OW divers in the event that they exceed their NDL's. And BTW technically SEI OW divers are certified to 100 feet as were the old YMCA divers. It is suggested to them that they stick to 60 until they develop the skills we teach them and gradually increase their depth. It is also suggested that they do AOW before doing so but it is NOT required. The AOW card is for the op and resorts. I could take any one of my OW divers and over the course of a few dives get them ok to go to 100 feet and not even issue a card. And in effect this is what I do. I insist on 10 OW dives before taking AOW for divers I've trained.

If I've not trained them then we will do some dives together or they will provide me proof or experience before I'll allow them to take it. Some agencies and if I know the instructor will make this usually unnecessary. NAUI, BSAC,CMAS, YMCA, and SEI OW divers I'm pretty sure are ok to do AOW after 10 post cert dives. But again I will do an interview and if during the first AOW dive they show less than adequate skills the class will stop till we figure out what is required to bring them up to snuff.

But in my AOW class they need to know how to do tables as we do cover deco using the SEI tables. All dives are planned and logged using tables. If I have to teach tables from scratch then that's an extra session and more money. It's one thing if they are rusty on them. It's another if they never did them. That being the case I'm gonna want to go over all skills and knowledge and maybe risk losing the student. I don't sell cards. They have to earn them and there is quite a bit of work involved in doing that for them and me. Even though I love teaching the advanced class by the time we're done with everything I require everyone is good and tired and so far better divers.

And last time I checked some a couple agencies require computers and do not teach tables at all.

 

[DA Aquamaster]

Theres a side of the argument that no one has mentioned yet.

When diving tables, diver are cautioned not to dive a "square profile". I learned to dive with US navy tables and as part of the training it was understood that when used on a square profile (remaining at the max depth for the max NDL at that depth for the whole dive) the tables had a hit rather of about 1% and this rose to 4% for repetitive dives. As a result we added in fudge facotors - next deeper depth or next longer time on hard working or cold dives and next deeper depth and time on hard working and cold dives, etc. We also normally took care to avoid staying at the max depth for the whole dive and rounded up - a 61 ft dive always became a 70 ft dive.

When you look at multilevel tables (PADI Wheel, etc) or at a computer one of the first things you should notice is that the the NDL's are much shorter, even when compared to newer tables based on doppler ultra-sound, Bulhman tables, etc. The reason for this is that the computer calculates depth and compartment loading every few seconds, so every dive is in essence a "square profile" and the only way to add in a safety factor is to reduce the NDL's.

But what that means is that the responsibility for adding in a safety factor shifts from the diver to the computer - unless the diver also knows enough deco theory to understand the limitations and the factors a computer may not consider, such as how cold you are, how hard you are working, how much you drank last night, your hydration state, how many dives in a row you have been diving, etc.

In my opinion, that knowledge is vital to using a computer safely.

 

[DevonDiver]

Fair points, but....

When a new computer user reads their manual (we all do right?).... they will see that they are recommended to use the in-built computer conservatism settings in the event of certain diving situations (cold water. exertion etc).

So, instead of planning "one depth level deeper" on a table, they just blip the appropriate button onto the appropriate setting of conservatism.

Same effect and, as alway'...easier to do on a computer than tables....