USING dive tables during OW course.

[Lorenzoid]

I believe that it would be a dis-service to any diver not to teach them how to use tables. While conservative they are a foundational principal that all divers should understand to better be aware of what is actually occurring on a dive. Having an understanding of the basic principles and their application only strengthens an individual.

Quick question - what "algorithm" are you talking about. Wondering if you are implying that an instructor covers the basic concepts (hence tables) or the mechanics of the actual algorithm used by the computer. For instance should an instructor be teaching the mechanics of say the Buhlmann, RGBM or Haldanean algorithms? Just wondering as most students tend to struggle with aspects of the Natural Gas laws and now we are talking about teaching advanced math.

Not saying this would not be interesting to cover - just might be a bit too much.

I most certainly didn't mean to imply getting into the details of decompression algorithms. In fact, my comment was based on a notion that a lot of students may not even know what the word "algorithm" means. I believe a student can get a feel for how a computer computes a diver's nitrogen load going up and down without using tables. The student only needs to grasp the concept that a computer continuously updates an estimate of the diver's nitrogen load based on some function (that is, an algorithm) of depth and time. I see no inherent reason why a student who is learning to dive using a computer needs to know that at some point during a simulation or planning exercise the diver is "in Group K" or whatever. For a student to learn to use a dive computer, the student only needs to comprehend some relative scale and how things change relative to that scale in response to depth and time. The scale doesn't have to be those letter groups in a table. The table is a mechanism that distills an analog or continuous function into discrete groups in order to enable easy paper-and-pencil calculations. It seems to me there are other ways to teach the concept than going through pencil-and-paper calculations.

What "basic principles and their application" could a student not learn without dealing with letter groups in a table?

I'm not saying it isn't useful to learn to use tables, especially if one is going to take their education further, but I no longer believe it is necessary for OW students to learn tables in order to competently plan and execute recreational dives with a computer.

 

[rhwestfall]

think you meant "inability".....

 

[Dthomas]

but I no longer believe it is necessary for OW students to learn tables in order to competently plan and execute recreational dives with a computer.

This is fine until their computer malfunctions, or they forget their computer. If the OW student or their buddy does not have a spare computer - what do you recommend if neither has been trained to use tables. If they are out of range of a dive shop to get a spare, they have nothing to fall back on and their is no diving.

I hope you are not suggesting we train OW Students that if there is only a single computer between buddies to dive with the one.

 

[Lorenzoid]

This is fine until their computer malfunctions, or they forget their computer. If the OW student or their buddy does not have a spare computer - what do you recommend if neither has been trained to use tables. If they are out of range of a dive shop to get a spare, they have nothing to fall back on and their is no diving.

I hope you are not suggesting we train OW Students that if there is only a single computer between buddies to dive with the one.

Well, that's certainly an argument for continuing to teach tables--as a backup. People who dive out of the range of dive shops and don't intend to own a backup computer should learn tables. But I suspect that does not describe the average OW diver these days. Computers aren't significantly more expensive than other required items of dive gear and are quite reliable. They will only become less expensive and even more reliable. At present, it seems that some cert agencies (PADI?) have decided that having a single computer is "good enough" to not require learning tables anymore. For most OW divers, they are rarely so far from a dive shop that there is no spare computer to borrow so they can begin diving again the next day. Even if one is out on a liveaboard--some of which require that every diver have a computer--they often have spare computers available to borrow/rent.

I think at some point we have to accept that we can rely on diving technology to help keep us safe the same way we have come to rely on technology in other areas of our lives to keep us safe. At this point in the discussion, I suppose I could come up with analogies involving cars, airplanes, etc., but the point is that when the relevant technology gets "good enough," we don't generally carry spares of everything or maintain the knowledge to do everything "manually" to fall back on. Sure, in the spectrum of activities that average people involve themselves in, diving is probably one of the more potentially hazardous, but that just relates to how reliable the gear needs to be relative to the potential danger, not to the principle that we inevitably decide to rely on technology when we make a judgment that the technology has gotten "good enough."

Pretty much every OW diver has access to a computer nowadays, and computers are quite reliable, and the consequences of computer failure generally need not be more severe than calling off a day or more of diving. Weighing that against planning dives using tables, which a lot of new (and even not so new) divers find cumbersome and not worth the trouble, I can see why cert agencies might decide to ditch the tables as a requirement for OW.

 

[Dthomas]

The problem with technology is that we are far to quick to do away with the manual way of doing things for the sake of technology. I am not saying we do not - not use technology, but it is crucial that we retain the other knowledge as well. My profession deals pretty much solely with computers and I am sad to say I see this trend all over the place. We are quickly becoming a "Click and drag" society that does not want to learn why things do what they do, but just that they do what we expect them to do. What happens when this system breaks and their is no one left who understands the foundations and we are unable to fix them.

I once read an article that basically said, one of the main reasons there were no new moon landings in the past decade was partly because there was no one left around who knew how to use the computer where all the calculations were stored. Could be true, could also be untrue - but it does make you think.

Rick Cook has a great Quote that was Goolgles Quote of the Day not all that long ago:

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe is trying to produce bigger and better idiots. So far, the Universe is winning."

I truly believe we are doing a disservice to our students if we are not training them on all the foundations.

 

[Diver0001]

Ok so Mr 13 has passed his OW theory.Hes done 3 DSD dives with a decent instructor.
Im really keen that he should actually USE the dive tables in the 'real world" during his JOW training so it has become a habit to calculate his loading.
The instructors are bemused at this idea.
Whats wrong with my thinking?

If I were you I would be keen to see him PLAN HIS DIVES, regardless of how it's done. Tables are one tool for that job but what is far more important is that he understands the principles involved and can plan a dive in advance.

In my frank opinion, I think where the rubber meets the road, dive tables are already a historical curiosity, some people just haven't realized it yet. With the prevalence of dive computers I'd much rather that my OW students understand dive planning with the tools they are going to be using than to spend a effort learning the ins and outs of an antiquated dive planning mechanism that they're unlikely to ever use or ever need.

That said, I still teach both for other reasons but I'm firmly in favor of OW students being encouraged to view a computer as required kit. I wouldn't write this post on a typewriter and send it to you via snail-mail because the technology of internet is a better tool for the job. The typewriter and snail-mail is all we had back when tables were developed. It would be silly to still communicate like that with one another and for the same reason I think it's silly not to adopt an attitude of modernization when it comes to the tools we use for diving.

R..

 

[ScubabunnyCR]

There's nothing wrong with your thinking. It is a very sensible and smart thought. Go with it! good practice for everyone involved : )

 

[rhwestfall]

What gets interesting as we see DC use grow to what is a constant mainstream (I see no problem with using a DC as the main tool) is the whole approach to diving with the "wonder device". The real issue at hand is not knowing what the information means. I can't tell you how many times I have seen folks just diving the computer, paying attention only to "no going too far into the yellow" because that may be how it was explained (not grasping what this relates to in NDL actual time on the clock). I love showing my insta-buddy my DC in a dive and seeing that he has no grasp of it because the little pixel graph isn't there. Only a clock displaying dive time, a depth read-out, and a clock counting down NDL time
(yes, some other stuff too....). Get a grip folks! Between dives I may run the tables for an SI, or use the DC to see what where I stand in NDLs for the next dive (gee, it does planning too?). Try discussing a dive plan with them for dive #2..... that is where the system has failed. Teaching tables may or may not set a better basis for DC use, but I think folks who have been through tables are better equipped...

 

[USFpsychDiver]

A dive table is a computational tool; it does not teach decompression theory. A dive computer is a more accurate and efficient computational tool; it also does not teach decompression theory. Should we go back to teaching our kids how to use slide rules in case their calculators give out (of course stand alone calculators are obsolete now too, but you get the point)? I carry two dive computers, and sometimes I dive with two computers. I may also use software programs other than the ones on my dive computer to help me plan my dives. I do not go round and round on my dive table figuring out which letter group I'm in and which letter group I'll be in after 45 minutes on the boat; there are more accurate and efficient ways to plan a dive an monitor dive progress. Should beginning dive students have some basic understanding of nitrogen loading, ongassing and offgassing? Absolutely! Are dive tables the best way to do that? If they still are, then educators need to come up with something better.

 

[Thalassamania]

Once again the real point is being missed. Tables or computer, it really doesn't matter, each is just a representation of a model. A table is a series of still photographs, a computer is an animate cartoon, both work. The issue is the misuse of computers to cut the class time that is spent on decompression theory. That is what is going on and I suspect will continue to go on. If a diligent instructor decides to teach computer only and does not scrimp on the deco theory topics, that's great, thoroughly acceptable, and (at least from my observation) rare as hen's teeth.