Question about the PADI Dive Table

[Dr Deco]

Dear Readers:

I would like to address two topic that appeared in this thread:

Teaching and Too Much Knowledge?

In my professional life as a scientist, I have given many talks over the decades; audiences ranged from children in grade school to adults. In all cases, I am certain that some of the material was “over the head” of the listeners and very often “beyond the topic.” I have always endeavored, however, to translate the material into words that were understandable by the particular audience, no matter how young. Thus, the individual would be exposed to a topic, if ever so slightly, such that, at a later time, they might revisit this should their interest grow.

I feel that decompression training for divers might be similar. Material a bit beyond can be of value, I believe, if it is verbalized in an understandable way. Certainly this presupposes the instructor know the material to a sufficient degree, and second that s/he can indeed translate it into understandable words. This is not a place to present a “snow job” designed to impress the students with the instructor’s depth of knowledge. There are no doubt possible limitations of a training agency, and that would be a contractual consideration.

US Navy Dive Tables

A comment was made concerning the US Navy dive tables and their testing or lack thereof. In actuality, the US Navy tables were for decompression diving and the vast majority of the tests were performed on decompression dives. Few tests were devote to determination of NDLs, although these could be derived indirectly from the total results of the test program. This, when a comparison is made between a recreational dive table (that only uses NDLs) and the US Navy tables (that are for decompression diving), one is inadequate in comparison to the other since the test programs – and ultimate goals - were quite different.

Dr Deco :doctor:

 

[iainwilliams]

This is not a place to present a “snow job” designed to impress the students with the instructor’s depth of knowledge.

Anyone who does this should NOT be an instructor in the first place! This is one of the points I was making - if instructor agencies became a little more concerned with who they give their licenses to, rather the number of licences (profit potential) - diving instruction would be much better and the information consistent accross the board. Enough said on this topic.............Iain

 

[DepartureDiver]

US Navy Dive Tables

A comment was made concerning the US Navy dive tables and their testing or lack thereof. In actuality, the US Navy tables were for decompression diving and the vast majority of the tests were performed on decompression dives. Few tests were devote to determination of NDLs, although these could be derived indirectly from the total results of the test program. This, when a comparison is made between a recreational dive table (that only uses NDLs) and the US Navy tables (that are for decompression diving), one is inadequate in comparison to the other since the test programs – and ultimate goals - were quite different.

Dr Deco :doctor:

Correct (of course) ... from pulling stuff I haven't looked at in years, the first part of the Navy table most of us know started in NEDU Research Report 5-57, M. des Granges (1956). If I remember correctly, this started the update of the very original Navy table and 453 dives were made to test 88 schedules. These were decompression dives. My entire original point was that when PADI introduced the RDP, they stated point blank (at least at the seminar I was at) that the Navy did very little testing on their tables and did less than 100 dives. I don't remember the exact number, but my recollection it came from "phase 2" of the Navy tests. Phase 2 is found in NEDU Research Report 6-57 which tested repetitive dives and surface intervals. This test was more limited than the first and only 75 combination dives were made due to "manpower limitations". So PADI was not completely incorrect, but they neglected to mention the 453 dives from the other test. They gave the audience the impression that the NAVY just never really tested their tables. I thought this was a little too much of a sales pitch and left the audience with wrong information. Now this certainly does not mean that the Navy testing was applicable to sport diving, but I did disagree with the presentation and the spin that was being placed on the information that was being presented.

 

[fins wake]

My involvement with PADI was from 1989 to 1996 when I was working as an instructor in Australia. A PADI course director actually sat in on one of my open water courses and made the comment that the course was far too technical for an open water diver, despite the advantagous benifits of a new diver knowing a little more about DCS and how to minimise a DCS hit. I wasn't advocating anything profound - just slow ascents, several stops at various depths, not working between dives during the surface interval, drinking lots of water pre and post dive, no coffee, no smoking (sex was OK) - and quite a bit more, but you get the drift. I used to give my students a wad of papers with graphs, tests and other data on the subject of DCS and diving conservatively. I also took them to the local chamber where the diving doctor gave them a speal of what was what!
The course director had a fit and said none of it was PADI material or sanctuioned

Sounds like a really good OW course. Also sounds like your CD was a ... uh, complete pillow spanker. If you get my cockney rhyming slang ... :winky:

No doubt, and before you current PADI instructors start pointing your spearguns at me, things may well have changed since 1996

Ah, them's spearguns frowned upon now, good Sir. :winky:

But seriously, I both think - and at least hope - things have changed since 96 and that you were unlucky with your CD (who hopefully hasn't spawned a bunch of moron OWSI clones ... or perhaps it should be clowns ...). For my part (and doing my OW after 1996) I had the benefit of the slow and multilevel ascent approach with no coffee in the surface interval (sadly no sex either) etc etc. The times they be a-changing. :winky:

 

[Dr Deco]

Hello DepartureDiver:

If the PADI speaker indicated that only a few dives were performed by the US Navy team, that was in error. I do know that often material is not presented correctly.

Whenever dealing with a writer and an interview, I always ask for a “read back” to check the facts. In some cases, it is lucky that I did.

Dr Deco :doctor: