Posted by Ken Kurtis on May 12, 2002 at 14:56:39:
In Reply to: Table posted by tecdiver on May 12, 2002 at 08:03:42:
tecdiver made some comments and drew some conclusions that need some clarifying. Here's what I think is more accurate:
("Pre-1987 PADI dive table was modeled after US Navy.")
Actually, the pre-1987 PADI tables weren't just "modeled after" the Navy tables, they WERE the US Navy numbers. Same held true for NAUI.
("Post-87 the model was Rogers and still is. Rogers and Huggins developed the model.")
Not quite. Karl Huggins, to the best of my knowledge, was not involved. (He came up with his own set of no-bubble numbers called "The Huggi Tables.") It was Rogers and Powell who developed the model, later joined by Lewis.
("DSAT is owned by PADI, so to say the developers of the model were independent of PADI is hogwash they were definitely affiliated.")
I don't think that's a fair statement. Although it's true that PADI funded DSAT (and I can't recall if it was even called DSAT back in the mid-80s or not), to the best of my knowledge, they had no direct influence on the research being done by Rogers & Powell. They were certainly aware of what was going on, and the whole goal was to develop a model that more accurately represented recreational, not miltary, diving. (The biggest change in the tables came from dismissing the 120-minute tissue as the controlling tisusue and going with a 60-minute tissue as the slowest one, leading to a 6-hour outgas rather than the previous 12, and resulting in shorter surface intervals with greater credit for off-gassing and less punitive residual nitrogen when you went back in.) But PADI was bascially in a position to take or leave whatever the findings were.
("After the table was in place and being used. Roger's and Huggins continued to research the model with field testing over a long period of time.")
Again, Rogers & Powell. Huggins wasn't involved. And I don't think there was really much field testing done, let alone over a "long period of time." My recollection from being at the seminar where these tables were first intorduced was thinking that these things hadn't really been fully tested and could we trust the numbers?
("Well simply put to many of the subjects were being bent doing repetitive dives. So PADI silenced them. They can never release their findings publicaly.")
This statement is an absolute fabrication. (Nothing like throwing in a little libelous slander to stir things up.) Besides, if what you're alleging was true, and PADI simply went ahead and released the tables anyhow, don't you think the general diving public would ALSO have been getting bent left and right? Simply hasn't happened. Your statement is a misconstruction at best, an outright lie at worst.
("So I concede I can not prove this without their data.")
Or that you can't prove this because what you're trying to "prove" simply doesn't exist. Where did you come up with this notion? You really should document the sources of your allegation if you want to stick to it.
("In conclusion I suggest if you are going to do repetive diving no what model your table or computer is based on.")
Since this isn't a sentence, I have no idea what you're trying to say.
However, if you're trying to suggest that ALL tables are mathematical models that may or may not pertain to your particular body physiology on a given day, and that you should dive them ALL conservatively and not push them to their limits, that's good advice no matter what tables or computer you adhere to.
Ken Kurtis
NAUI Instr. #5936
Co-owner, Reef Seekers Dive Co.
Beverly Hills, CA