Ascent Rate History

[Akimbo]

Where did the venerable 60 ft/min or 18m/min come from, and when?
Surprising account by someone who was there....
View attachment 201427

I forgot to thank you for the link. Where did you find it? Are there any more documents of interest?

The U.S. Navy adopted the Royal Navy tables (Haldane’s 1907) without a lot of change, and the first USN Diving Manual (1916) made not faster than a foot per second the rule. However, sometime between 1916 and 1943, this rule was changed. The 1943 USN Diving Manual says, the diver's ascent should not be greater than 25 feet per minute. Nobody now seems to know when or why that change was made.

It sounds like any more detail than that is lost forever if Dr. Lanphier couldn’t find the information in the comparatively tiny EDU library at that time. I have been wondering about the progression of ascent rates for a long time. This thread got into ascent rates starting around post #9:
http://www.scubaboard.com/forums/basic-scuba-discussions/491271-navy-dive-tables.html

 

[tursiops]

I forgot to thank you for the link. Where did you find it? Are there any more documents of interest?

I'm not sure where the article came from or when: it is cited (bottom of the page) as "The Best of Sources" page 32....and I had a hard copy of that page collected from somewhere at some point. My GoogleFu is pretty good, but I can't locate any real source (so to speak).

But this publication, http://www.si.edu/dive/pdfs/proceedings_safeascents.pdf, contains on pages 5-8 much the same material, some of it pretty much word for word....but I don't know which came first. This linked version of Lanphier's historical remarks is actually much more interesting than the one I sent first.

---------- Post added January 19th, 2015 at 09:22 PM ----------

Additional. The complete Illustrated Guide to Snorkel and Deep Diving, by Owen Lee with a forward by JY Cousteau, published 1963, says on page 219 in a section on "No-Decompression Rules of Thumb": "These rules, created by the U.S. Navy prior to 1956, account for an ascent rate of no more than twenty-five feet per minute. This old standard rate of ascent was revised to sixty feet per minute in 1959." Owen was the only American diving with Cousteau in 1959 when he joined the team, and dived with them for the next decade. His story is at Owen Lee's Book and Videos on Ecology and Zihuatanejo.