Dive tables...

[fnfalman]

I was just thinking what is so complicated about dive tables so I started looking at images of the various agencies and looked at PADI's dive table and went ok I am having issues figuring that one out, then I went to the SSI dive tables that I am a little more familiar with and went ok this is layed out easier to read with not having everything showing in the same table. I am sure once I become more familiar with reading the dive tables I could look at the others and read them too, just have to relate the information back to what I know.

The reading is the same though the layout is different. I have PADI/DSAT and NAUI tables and I can read any of them.

 

[avengerki]

True the reading is the same, but if you are just getting into diving and see the tables that have everything consolidated you may be feeling overwhelmed. I find by having it split up it makes it easier to understand. I have looked at similar tables in the past for other things and find that having it split up makes it easier to understand even though now when I go to use them I will use a consolidated table. It also doesn't help that I sometimes get a little number dyslexic so seeing alot of information in one table while learning them can frustrate me(it is even funner when looking at a table and you watch the number start floating around)

 

[TMHeimer]

I guess it all depends on your style of diving and where you dive. Not having a lot of reefs in Pa and Ohio/West Virginia I do very often dive pretty much square profiles as do my students. And they are encouraged to until they have their basic skills down. They are not encouraged to follow a DM and and do whatever they do. They don't need to dip into every little canyon and follow drastic contour changes. And they are told about watching their depth and trying to maintain a more or less consistent depth whenever possible. Whether or not they do is up to them once they leave the class. Myself I practice what I teach and do keep track of avg depth either on a slate or at this point my Shearwater Predator does do avg depth and dive plans are planned as square profiles. Even on vacation I like to do multilevel, yet still for the most part square profiles, where for me it is fun to do that. Then again I'm really not into reefs and fish ID. If I could I'd only do wrecks and those are by nature often square profile dives.

My diving is mostly the same as yours --mostly square profiles and a lot of shallow dives. When I do a true multi level dive (computer) it is frustrating when I can't fill out my log using max depth and pressure groups. I am a creature of habit.

 

[diverrex]

My dives are all very multi level which is why I have no interest in tables. Plus I'll often do the first dive on Nitrox then 2 or 3 more on air, not sure how well the Nitrox and air tables mix, but no problem for a computer.

 

[NAM001]

I owuld guess that you should have no problems in the future. I have found that from bouncing from one agency to another the tables they use and the mechanics of using them differ so that learning one agencies table operation may not help you in another agencies table lay out. ultimately they all work the same. some are on pne page others 2 or 3 pages some you go in circles and others not. As long as i think of tables as a credit card, it works for me and i can visualize if something is amiss when using another table layout or format. i have a starting ballance and a credit limit., i charge dive time with bottom time and i have SI to act as a c/c payment. the next dive start ballance now has a negative ballance on it. Because i look at it like that ,,,,,i can see that something is wrong if my use of the table shows that my group is not changed after the SI. Then, all that effort is for not when you dont dive a square profile. Next even though you learned them once, you later move on to more in depth training and you will be taught them all over again. because the mechanics you learned before may be different. Depending on who you ask you wil get a thumbs up or down on the tables. The rec divers will mostly say tables are not necessary, or class only. The techies will have a different opion , and rightfully so. Thier type of diving is not the same as rec diving. A similar analogy wwould be whether one flying in a plane needs a parachute or not. the United passenger says no. The military fighter pilot says yes. I started with ymca and had an introduction of tables. Course ended never used them. Some 10-15 years later i did a padi course and tables had to be relearned. Still did not use tables this time because with a depth gage and a watch all is well, computers were coming of age and except for log book use the tables were not needed by me. I then went nauii and did nitrox, tables again and defnately did not use them other that for test ?'s. i had a computer ( too easy to make a mistake). Then on to iantd for adv rec trimix and the tables have now found some relevnace. I still dont use them becuase i use my computer to preplan the dive and in event of a computer failure i thumb the dive and head to more forgiving territory. I would guess that if i were to start to make 200 ft dives the computer would take on a lesser role and probably Ratio deco methods would take over. No matter what so long as different tables are around the future trainign wil have to teach you thier courses tables if tables are in the curriculum. Dont worry , Be happy

So I took an SSI open diver course and in it we didn't really cover dive tables as it isn't really in the curriculum anymore. We did spend about 5 minutes on them and I don't really have any issue reading and using them but will that cause any problems in future classes?

 

[TMHeimer]

My dives are all very multi level which is why I have no interest in tables. Plus I'll often do the first dive on Nitrox then 2 or 3 more on air, not sure how well the Nitrox and air tables mix, but no problem for a computer.

Yeah, tables no good for multi level, and unless you're at specific levels for specific times (ie. not gradually ascending throughout), the eRDPml is pretty useless. If you do square profiles the Nitrox & Air tables mix fine--you just use whichever one for the appropriate dive.

 

[Storker]

I am a chemical engineer and the first time I was taught to read the dive tables, I was like, "WTF, over?" If a chemical engineer who is trained to generate algorithms and reading charts were having trouble with the explanation of dive tables, what do you think about soccer moms and joe schmoes?

You've got a college degree in engineering and you had problems understanding dive tables? :shocked2:

Sorry, but I have some problems relating to that statement. While reading up for my OW class I needed about five minutes with the PADI how-to-use-the-RDP manual to work the table just fine, and although I can sympathise with "soccer moms and joe schmoes" who have problems mastering the tables at the first attempt, it's not exactly rocket science.

On topic: I wouldn't like to be without my training in how to use a table. It gave me a feeling for nitrogen loading and NDL which I doubt a "just follow the computer" approach would have given me.

 

[diverrex]

On topic: I wouldn't like to be without my training in how to use a table. It gave me a feeling for nitrogen loading and NDL which I doubt a "just follow the computer" approach would have given me.

When people talk about not teaching tables that doesn't necessarily mean they are only taught "just follow your computer". The concepts of nitrogen loading, off gassing etc can be taught without tables. They in fact can be taught effectively by using a computer. I do see the value in using tables as a graphical teaching aide to teach the concepts but also can see it done by other means. I have no interest in using tables, I use my computer instead. However I have great interest in the concepts of nitrogen loading. The only thing I've asked my wife to buy me for Christmas is "Deco for Divers".

 

[boulderjohn]

Side comment -- I always have to laugh at the people who say "My brain doesn't fail" because a computer might fail -- then you must not be human (or at least as old as I am).

Two of my friends got bent diving under the "my brain doesn't fail" system. One of them was using a computer in gauge mode to tell depth and time, so it recorded the dive profile. They were basing their ascent profile on average depth, calculated with their brains as they had been taught. The computer profile showed that they were actually an average of 8 feet deeper than they had calculated. They then began the ascent according to their plan. The computer showed that they somehow did not notice that it took them three times as long to get to their first stop as they had intended. In other words, their mental calculations screwed them to the point of DCS. The computer they were ignoring had it right.

Learning to use and understand the tables gives a deeper understanding of the physics of diving and the need to following safe diving profiles and practices. It is where we learn the "WHY" of so many things. The alternative is to teach student to "do what the computer tells you."

I am sure that is where you learned the "why" of many things, but that is only because it was when your instructor chose to teach that "why." Mark Powell wrote an entire book on the "why" without once teaching the tables anywhere. How did he do it? The theory of decompression has nothing to do with tables. It has nothing to do with computers. Tables and computers are how we plan and measure our efforts to prevent decompression sickness. I have NEVER taught decompression theory with the tables. I have always taught decompression theory first, showing students how and why we have nitrogen building in our tissues, and why it is necessary to follow a safe ascent profile.

Once they understand that, I teach them how to plan a safe ascent profile. I have taught it with tables. I have taught it with the eRDPml. I have taught them with V-Planner. I have taught them with Ratio Deco. I have taught it with computers. I have a Powerpoint that shows how a computer tracks nitrogen levels during a dive--it really shows the process well.

Decompression theory and the way we prevent decompression sickness are two different things.

 

[BDSC]

I am fortunate enough to live near the DAN headquarters in Durham, NC. Every other month they have a presentation that is open to the public so they can "try out" some of their presentations before taking them on the road to a much larger audience. One of the recent presentations was on DSC, how it occurs, how to detect it, and what we can do to prevent it. It was a great presentation and for the most part easy to follow what he was saying. Not once in the entire presentation did he ever use or show any type of table like this thread is talking about.

I guess I have never understood when a person says that by teaching or showing a person the tables, that somehow the numbers on that piece of plastic helps them understand or grasp the theory of diving any more than showing them those same numbers on a computer.