Teaching Dive Tables (including Nitrox)

[Gelirfella]

Just finished an SSI OW course and my instructor taught us tables and we solved some problems. Was helpful for highlighting the strength of nitrox in reducing surface intervals.

 

[rick00001967]

when i last taught, ssi still included the tables in the online learning material but it was in the appendix.

when we still did proper in class academics, i was always a fan of discussing the tables. as others have already pointed out, they are a great tool for introducing the concepts of bottom time, ndl, surface intervals, safety stops etc etc. and the need for proper dive planning. i think it helps the student understand what a dive computer actually does, and what the benefits are.

lets also remember......you cannot plan a series of dives using a basic recreational dive computer.

to me, teaching dive planning without mentioning dive tables is like teaching kids basic math with only a calculator. but i am sure many will disagree.

 

[boulderjohn]

There was an interesting thread on a similar topic only a year or two ago, IIRC. A new SSI diver was distressed to learn that computers were so inaccurate. To sum up a complicated thread briefly, he had done his OW class with the SSI tables, and he assumed that the SSI tables were perfect. The fact that dives done with computers were showing different results meant that the computer algorithms were all wrong.

 

[formernuke]

Depends.

For PADI the students can choose to learn tables. Not sure about other agencies.

Then of course the instructor can opt to teach them.

 

[Dan G]

There was an interesting thread on a similar topic only a year or two ago, IIRC. A new SSI diver was distressed to learn that computers were so inaccurate. To sum up a complicated thread briefly, he had done his OW class with the SSI tables, and he assumed that the SSI tables were perfect. The fact that dives done with computers were showing different results meant that the computer algorithms were all wrong.

One thing I recall being emphasized in my SSI Science of Diving course is that NDL calculations in general are still quite theoretical. What struck me, however, is that the tables have very precise calculations on them. Group X with a SI of 33 minutes? You are now in Group Y" 32 minutes? well that's a whole different story. The tables certainly give the impression they are exacting.

 

[EFX]

One thing I recall being emphasized in my SSI Science of Diving course is that NDL calculations in general are still quite theoretical.

I took the same course a few years ago. The book (copyright 2010) that came with the course was quite good except for the section on decompression theory. There were some outright errors and misleading statements. For example, on page 3-13 in regards to dive computer calculations we have this gem: "Going deep, then shallow, then deep again will yield unreliable results." I hope this section was rewritten in a later edition.

In regards to NDL calculations being theoretical then I guess deco stop time calculations are theoretical because both NDL (time) and deco stop times are calculated the same way. But why stop there. Those calculations are based on the inert gas tissue (compartment) loadings which of course are theoretical!

Edited at 1943 EST.

 

[Keith Blair]

I teach through SSI and the tables are briefly mentioned in the student online academics and the tables themselves are available through the SSI mobile app. In my OWD classes I make it a point to teach dive tables and have the students go through a couple of sample dives using the tables.

In a perfect world, every diver would own/use a dive computer, batteries would never die, and underwater electronic devices would never fail. Since we don't live in that world, I want my students to know how to use, or at least have some foggy memory of how to use, a dive table should the need arise.

Having knowledge you don't need is better than not having knowledge you do need.

 

[boulderjohn]

Having knowledge you don't need is better than not having knowledge you do need.

Most instructional theorists would disagree.

In good curriculum design, you identify the essential learnings and make them the focus of the course. You identify the things that are good to know and give them secondary focus. Things that are nice to know are given the least focus.

Most importantly, you identify what is not needed, and you eliminate it. Time spent learning things that are not needed detracts from the student's ability to learn what is important. This is called interference theory.

 

[Eric Sedletzky]

I teach through SSI and the tables are briefly mentioned in the student online academics and the tables themselves are available through the SSI mobile app. In my OWD classes I make it a point to teach dive tables and have the students go through a couple of sample dives using the tables.

In a perfect world, every diver would own/use a dive computer, batteries would never die, and underwater electronic devices would never fail. Since we don't live in that world, I want my students to know how to use, or at least have some foggy memory of how to use, a dive table should the need arise.

Having knowledge you don't need is better than not having knowledge you do need.

Just out of curiosity, what dive tables does SSI use?
Do they have their own?

 

[boulderjohn]

Just out of curiosity, what dive tables does SSI use?
Do they have their own?

They have their own.