PADI tables finally going away?

[gcbryan]

I did my first 120 dives or so using tables. Those dives were the best of my life: Singapore, Malaysia, Thailand, the Maldives. Of course I like tables. Specifically, the NAUI tables.

But Nitrox complicates life. Not only do I need to fiddle with the computer to make sure it has the right mix and then watch the NDL, I have a new thing with total oxygen (OTL - Oxygen Toxicity Limit, as it's known). One more thing to mess with and another table to use if I'm not using a computer. Now your NDL is the shorter of nitrogen uptake or oxygen exposure limit. Both, of course, are a function of depth and time. That's just too much stuff to write on a slate and track underwater. So, I bought a computer. Four of them for our small herd.

When you go to buy your computer, have them demonstrate ALL of the functions. Pay careful attention to the menu navigation. Pay even more attention to what you might want to do while submerged. Three button computers are easier to use than 2 button computers which are (perhaps) easier than 1 button computers. I had a long discussion with a fellow one day and we came to the conclusion that the more buttons the easier. But they need to be big buttons and well spaced for cold water mittens. Look at the owner's manual. If it is written in Klingon, try another computer.

I don't believe a 5 minute introduction is sufficient for a computer that tracks altitude, fresh/salt, ppO2, a couple of mixes, nitrogen bar graph, oxygen bar graph, alarm indications, ascent rate indication, Nitrox mix default at midnight, etc. There's just more to it than that. Like log book functions, PC interface functions, downloading, battery replacement, etc.

One problem with some computers is that the only time you can see an alarm icon is a) in the book, b) on the startup screen where it is surrounded by jibberish and c) when it applies to you and you are underwater. AFAIK, very few computers let you simulate a dive and see what the display will look like when it really matters. The first time you get that mandatory deco indication may be the very first time you have ever seen it. "Hm... I wonder what that means?" I don't think any of the manuals can be used under water.

One computer that does allow for dive simulation is the Liquivision X1 with the V-Planner Live software. It's terribly expensive. I WANT one...

Sadly, I don't think you will find more experienced divers that are still using tables. I understand your desire to dive with more experienced people. I felt the same way. That's why I took NAUI OW I, OW II, Advanced OW and Rescue as back-to-back courses. I spent a lot of time with the instructor before I ventured forth to conquer the oceans.

Here's an Oceanic computer for $200 Oceanic Veo 180 Wrist Computer Another for $150 Oceanic Veo 100 Wrist Computer (My grandson has this one in a console).

Here's one that costs a bit more but the downloader is CHEAP! Uwatec Aladin Prime Wrist Dive Computer I bought this for my wife but she took my NiTek Duo so now I'm using it. It takes an hour or so to catch on to the menu navigation. The book doesn't help. As to downloading: you need an IR dongle for your PC like this: DealExtreme: $4.83 USB IRDA Dongle The software is EXCELLENT and it comes free with the computer.

Don't overlook the cost of the downloader gadget. For the NiTek Duo it is a couple of hundred dollars depending on where you buy it. I got a couple of these computers at a great price from ScubaToys but the last time I looked, the price was back up where everybody else is. I think I paid $50 for the downloader as an incremental cost for the computer.

If you really want, and you probably won't, you can put most computers in GAUGE mode and dive tables. As a refresher, perhaps?

Richard

For what it's worth you don't need a Liquidvision X1 to get dive planning/simulation. You mentioned the Oceanic Veo 180 for your family...I have an older model of that (the Veo 200) and it has a simulation mode. You can't do repetitive simulations (it won't remember nitrogen loads from one simulation to the next) but it will demo the deco screen or anything else you require.

I only used that feature once and don't think it's really all that valuable but if anyone is interested in that kind of thing it's available on some of the cheaper computers as well.

You mentioned the expense of the downloader with the Nitek Duo. I have the Tusa version (IQ 700) and didn't bother with the downloader but it does have a replay mode in the computer itself (speeded up of course) so some may feel that is enough and not need to incur the expense of the downloader.

 

[HowardE]

When you go to buy your computer, have them demonstrate ALL of the functions. Pay careful attention to the menu navigation. Pay even more attention to what you might want to do while submerged. Three button computers are easier to use than 2 button computers which are (perhaps) easier than 1 button computers. I had a long discussion with a fellow one day and we came to the conclusion that the more buttons the easier. But they need to be big buttons and well spaced for cold water mittens. Look at the owner's manual. If it is written in Klingon, try another computer.

Oddly enough; most of the more technical diving computers are 2 button computers. They're just easier to use

I don't believe a 5 minute introduction is sufficient for a computer that tracks altitude, fresh/salt, ppO2, a couple of mixes, nitrogen bar graph, oxygen bar graph, alarm indications, ascent rate indication, Nitrox mix default at midnight, etc. There's just more to it than that. Like log book functions, PC interface functions, downloading, battery replacement, etc.

This is why - computers shouldn't be taught instead of Tables. Each computer is different. Reading the manual is important, and understanding the concepts are even more important. PPO2 and "a coupe of mixes" are not topics for new divers who are just learning dive tables. Those are more advanced topics, and if the user doesn't understand the concept, the dive computer functions that apply to those concepts like; oxygen bar graph, or a couple of mixes wouldn't need to be accessed to make a safe dive. At the most basic level, a dive computer will do the dive, with no adjustments necessary.

One problem with some computers is that the only time you can see an alarm icon is a) in the book, b) on the startup screen where it is surrounded by jibberish and c) when it applies to you and you are underwater. AFAIK, very few computers let you simulate a dive and see what the display will look like when it really matters. The first time you get that mandatory deco indication may be the very first time you have ever seen it. "Hm... I wonder what that means?" I don't think any of the manuals can be used under water.

This is also why people shouldn't dive beyond their limits, and they shouldn't learn about staged decompression from their computer's settings. If a course in Deco Procedures was taken, the computer displays when you get a ceiling would make total sense. Also - how do you teach this to basic open water students? This is why the manual specific to your dive computer is important.

Sadly, I don't think you will find more experienced divers that are still using tables. I understand your desire to dive with more experienced people. I felt the same way. That's why I took NAUI OW I, OW II, Advanced OW and Rescue as back-to-back courses. I spent a lot of time with the instructor before I ventured forth to conquer the oceans.

Many more experienced divers cut their own tables using desktop planning software like v-planner.

Silly as it might be, I can actually PLAN to overstay the NDL. Not a good idea but at least the table tells me how. Not too many computers let you see a plan that overstays the NDL. They'll let you do the dive but they won't let you plan it,

But the dive table was always in my BC pocket. Software doesn't do much in terms of accidentally overstaying a limit. I would never recommend deliberately overstaying.

I'm not sure if I'm understanding this... but you're telling me that you do "uh oh deco" with your dive table? on the fly? So... while you're diving. You conclude that you've exceeded the limit of the table, and then you pull out the dive table to see ho long you have to make a 15' stop for? Personally... I either plan on making a deco dive, or a no-deco dive. "Accidentally Overstaying a limit" is poor dive planning.

 

[DA Aquamaster]

And one last thing: the NAUI dive tables contain deco entries should you happen to overstay your NDL. Let's suppose you overstayed the 25 minute NDL for 100 feet and got a little closer to 40 minutes. No problem, just hang at 10' for 15 minutes. This based on the 1987 NAUI table which I just happened to grab out of a pile.

Silly as it might be, I can actually PLAN to overstay the NDL. Not a good idea but at least the table tells me how. Not too many computers let you see a plan that overstays the NDL. They'll let you do the dive but they won't let you plan it,

No, I don't recommend overstaying the NDL. I'm just saying that the NAUI tables are pretty nice. Too bad I can't read them underwater any more.

I understand what Richard is saying here - the PADI tables of the same era had the same capability - they essentially included all of the times and depths on the US Navy Tables with no more than a 10' deco stop and were noted to be for "unintentional" decompression.

The idea of planning for the possibility of deco is fairly consistent with the still used procedure of contingency planning for next greater depth and time, which if applied to a dive to an NDL, the contingency plan would result in some deco planning and that was the basic premis of the "unintentional deco" portion of the table. There is still today nothing really wrong with that if the diver is properly trained and configured for deco diving.

But the dive table was always in my BC pocket. Software doesn't do much in terms of accidentally overstaying a limit. I would never recommend deliberately overstaying.

The planning functions on recreational dive computers are extremely limited and planning for "unintentional" deco is not an option. Even on technical diving computers, actual deco planning is usually complicated and/or requires a lap top.

In that regard it is far easier to use a set of tables to do the dive planning - either in the form of actual tables or more commonly in the form of deco software to cut custom tables for the dive and mizes being used. I use D-Plan and Palm VPM as they both work very well on an inexpensive Palm device. Compared to a lap top, it is very small, very light, very portable and very inexpensive so if it gets lost or broken on the boat, I am not out much money.

Between adjusting the conservatism on either of my dive computers or adjusting the gradient factors in D-Plan I can get both the soiftware and computers to produce very similar profiles on a given dive. The dive is then planned with the software on the Palm, with the dive plan, contingency plan and lost deco gas contingency plan(s) transferred to a multipage wrist slate and the dive is run with the bottom timer providing primary depth and time information. The computer is basically along as back up.

------

But the point needs to be taken in either case - being able to do the planning allows the diver to be aware of the gas required to do the deco if the need arises. The argument then becomes does this additonal diver provide a safety factor for the diver, or does it provide encouragement for them to exceed their training?

I'll always argue the former on the premis that if a diver is dumb enough to do the latter, limiting the information they have access to will not save them from their own stupidity. Instead it just removes some tools from the emergency tool box for those divers who are not irresponible or stupid.

 

[rstofer]

This is why - computers shouldn't be taught instead of Tables. Each computer is different. Reading the manual is important, and understanding the concepts are even more important. PPO2 and "a coupe of mixes" are not topics for new divers who are just learning dive tables. Those are more advanced topics, and if the user doesn't understand the concept, the dive computer functions that apply to those concepts like; oxygen bar graph, or a couple of mixes wouldn't need to be accessed to make a safe dive. At the most basic level, a dive computer will do the dive, with no adjustments necessary.

OK, don't tell the new divers about the settings they may accidentally screw up? If the computer has the capability of doing Nitrox, the diver needs to know how to get it OUT of that mode. Buttons get pushed, settings get changed. NDLs get extended... Oops!

I don't think I have seen a computer with a "Master Reset" button that would restore factory defaults (other than the Liquivision). It might be a good thing to have.

I don't think ignorance of the features is a viable plan. Maybe there should be different levels of computers: OW, AOW, Nitrox, MSD, DM, Inst. Not a bad idea, actually! If the feature doesn't exist, it can't get hosed.

There is also the problem of reading the manual. A lot of people, myself included, don't learn well from books. There are different methods of learning and I tend to learn best from tell-show-do.

Many more experienced divers cut their own tables using desktop planning software like v-planner.

Yes, but that's not the experience level I would recommend a new diver team up with. I think the new diver is well served if they team with another recreational diver at perhaps the Rescue level. Although MSD, DM and Instructor are also good candidates.

Teaming with a tech diver may well lead to information overload. OW divers should hang out at 60' or less. I don't see the advantage of V-Planner on a 60', no-deco, recreational dive.

Just take more classes. These dives will expand the skill set and are supervised.

I'm not sure if I'm understanding this... but you're telling me that you do "uh oh deco" with your dive table? on the fly? So... while you're diving. You conclude that you've exceeded the limit of the table, and then you pull out the dive table to see ho long you have to make a 15' stop for?

Sometimes bad stuff happens. Not to me, of course. But to other divers. At least in the case of the NAUI tables, they make an attempt to help you recover.

That's another neat feature of some computers! If you get in a position where a deep deco stop is required the computer ABANDONS you. It simply pukes and displays "Use Tables". Right in the middle of the dive. There you are, down deep, low on air, totally screwed and your computer pukes. Sure, you shouldn't be there. But there you are...

That's another thing to look for when selecting a computer. Read over what happens when you get in deep trouble. If the manual even hints that the computer will abandon you, try another computer.

One of the nice things about the NiTek Duo is that it does NOT abandon you. It may think you are an idiot but it waits until you surface to lock you out.

Richard

 

[Blackwood]

This is why - computers shouldn't be taught instead of Tables. Each computer is different. Reading the manual is important, and understanding the concepts are even more important.

I know you aren't suggesting that all tables are the same, and that reading the manual and understanding the concepts are unimportant, but still I don't follow that post.

That's another neat feature of some computers! If you get in a position where a deep deco stop is required the computer ABANDONS you. It simply pukes and displays "Use Tables". Right in the middle of the dive. There you are, down deep, low on air, totally screwed and your computer pukes.

Bolded for emphasis.

If you don't have enough gas to make a safe ascent, it doesn't matter whether a Table, a Computer, or Flying Spaghetti Monster himself tells you to make stops.

 

[D_B]

Understanding the info that your given, is important .. whether it's your computer, your tables, or your software

Are there really computers that lock in the middle of your dive if you go into deco, or deep deco ?

even though I know it has suggested deco stops for being over NDL by 5 or 10 minutes, I feel like re-Reading the deco info on my VEO250 again

... says that it can not calculate deco obligations for stop depths much over 60ft (over 70ft)
you need to ascend to just under 60ft depth for it to to continue calculating deco time ...if you do not ascend to just deeper than 60ft, it will revert to gage mode

60ft sounds pretty deep for an "accidental" deco obligation caused by an NDL overstay by just a minute or two at recreational depths

I need to see what a deco planing software has to say about what would cause a greater than 60ft stop depths

 

[lowviz]

..........I think it's time for PADI to reduce the info on tables in the OW book and take out students having to actually learn the table. .............

Are we getting close to agreement? (Where is Blackwood's horse?)

Seriously, How about just requiring OW's to memorize air NDL's forward and backward for 40', 60', 80', 100',and 120' instead? Add a touch of basic gas management. Given an 80cuft tank, where can you get into trouble? We all know the answers to these questions off the top of our heads because we were taught the tables in OW.

I'm fine with leaving the tables for AOW, just make sure that AOW's actually learn them.

Stay safe.

 

[H2Ohm]

An engineering student uses computers, graphing calculators, oscilloscopes, etc. in order to do whatever it is they do but they still need to take the appropriate math/physics courses in order to know and understand the 'how's' and 'why's'. The same applies with dive theory. Just like everything you do in life...you should learn the basics first. Teach basic dive theory first, then move on to the more advanced tools and applications.

 

[rstofer]

Are we getting close to agreement? (Where is Blackwood?)

Seriously, How about just requiring OW's to memorize air NDL's forward and backward for 40', 60', 80', 100',and 120' instead? Add a touch of basic gas management. Given an 80cuft tank, where can you get into trouble? We all know the answers to these questions off the top of our heads because we were taught the tables in OW.

I'm fine with leaving the tables for AOW, just make sure that AOW's actually learn them.

Stay safe.

I never memorize anything I can look up. Too many brain grenades in my youth.

Further, it does no good to memorize the first dive NDLs because the adjusted NDLs for subsequent dives can be all over the map. It's an all or nothing deal. Either you know how to use the tables or you don't.

I think the real fallacy started long ago. Somebody decided that the tables were too hard for divers to learn but they still wanted to certify the divers. So they shortchanged the requirements instead of dumping the students. The fallacy? Not everybody that wants to dive should dive.

A better approach would have been like the old NAUI scheme: you learned the tables, passed the tables portion of the exam with 100% or you didn't get certified. It was really that simple. Either you knew the material or you didn't dive.

The whole idea of lowering standards to some lowest common denominator to accommodate those that are too lazy to learn how to use a simple table is simply stunning. Kind of like "kids can't do math, let's play soccer instead".

So now we introduce computers with complexity beyond comprehension and expect the same lazy students to somehow learn to use something that is much more difficult than a simple table.

Using the table keeps the diver in touch with their diving. It's like GPS in a way. In the old days of navigation (celestial, loran, coastal, etc) it was necessary to refer to a nautical chart to figure out where you were. In doing so, you could see on the chart the things you might run into. Depth was clearly indicated, for example. Wrecks were annotated.

With GPS and autopilot, we saw a huge uptick in wrecks because it was no longer necessary to relate the position on the GPS to the nautical chart. The GPS didn't know about submerged objects and even if it did, it didn't care. Selective Availability didn't help!

The only good news is that this stuff really doesn't matter. There simply aren't enough DCS injuries to make the case that divers, in general, are unsafe. They may not understand tables, they may not understand their computer but they are smart enough to stay under the NDLs and avoid injury. On average...

My suggestion: require tables at the 100% proficiency level in OW. No excuses, no calculators (eRDP). You know the tables or you don't dive.

Then, have a minor specialty class in computers. Not a 5 minute presentation, something with a little meat. Maybe a couple of hours. Perhaps the course is tailored to the specific computer the student is buying. There could be a formal list of topics to cover without being specific to a particular computer. Instructors for the LDSs could tailor the presentation to comply with the guidelines yet be specific to the computer.

Since this specialty is related to equipment purchase, I would expect it to be free (except for the C card) with the purchase of a computer.

Richard

 

[DA Aquamaster]

Seriously, How about just requiring OW's to memorize air NDL's forward and backward for 40', 60', 80', 100',and 120' instead? Add a touch of basic gas management. Given an 80cuft tank, where can you get into trouble? We all know the answers to these questions off the top of our heads because we were taught the tables in OW.

It's not a new concept. For example the general wisdom was that with a single steel 72 you could not get bent on a single dive in a 12 hour diving day. That was based on the old US Navy tables - but when you consider more conservative NDL's on modern tables it is no longer true. Then again, when you go with Nitrox, you end up with more or less the same "hard to get bent on a single tank" situation.

In my case, at the time I used my SAC rate and the US Navy tables to figure out how true that really was - and it was down to 90 ft. Deeper than 90 ft getting bent was a possibility on a single steel 72.

So, I suppose if you limit divers to 60', for a single dive per day and a single tank of 80 cu ft or less per dive, you could perhaps skip tables entirely at the OW level. But is it a good idea to water down the OW course more than it already is? It is not like learning tables is difficult, and if it is, should that person really be diving?

Or look at it the other way. If you are an OW student and are learning all the other skills, would you be willing to learn the dive tables if it allowed you to make 2 or 3 dives per day rather than 1?