Where did the 135 foot / 40 meter recreational max depth limit come from?

[Edward3c]

What year is that from?

I got the logbook in 1978, but the table had been in use a few years by then.

 

[captain]

1988, could have been late 1987

I believe the wheel came out in 88, I think the PADI tables came out 79-80

 

[scubadada]

I believe the wheel came out in 88, I think the PADI tables came out 79-80

Deco for Divers, Mark Powell, 2014, p 176:

The DSAT Recreational Dive Planner (PADI) model (1987)

The M-values used for the RDP were adopted from the Doppler bubble testing and tested by Dr Merrill Spencer and tested by Dr Raymond E Rogers, Dr Michael R Powell, and the colleagues with Diving Science and Technology Corp, a corporate affiliate of PADI. The DSAT M-values were empirically verified with extensive hyperbaric chamber and in water diver testing and Doppler monitoring.

I believe the information is also in the 1994 article by RW Hamilton et., The DSAT Recreational Dive Planner, available on Rubicon 2007. I don't have the citation, but @dmaziuk does

 

[John C. Ratliff]

I think I found the article. I'm downloading it now.

Development and validation of no-stop decompression procedures for recreational diving: the DSAT recreational dive planner.
From this paper:

2. Decompression and Stops

In the vernacular of recreational diving the words "decompression" or "decompression diving" usually refer to an ascent which requires that decompression stops be made (for the purpose of avoiding DCS). If the amount of dissolved gas is too great to permit direct ascent to the surface, decompression "stops" are necessary. This involves an interuuption of ascent at specified depths for specific times; it is sometimes called "stage decompression." Thus a "decompression dive" is one requiring stops, while a "no-decompression" ascent requires no stops. The fact is, all dives involve decompression since dissolved nitrogen must be eliminated at the end of the dive, but they do not all require stops. To furthe confuse the issue, a sufficiently slow ascent can take the place of stops (Lang and Egstrom, 1990). We prefer in this report to refer to dives without stops as "no-stop" dives, to avoid the implication that decompression is not involved; it always is.

A "safety stop" at 10 to 20 fsw for 3 min is required by the RDP on all dives exceeding certain limits. A "safety stop" is a stop that is not required by the computational algorithm, but is there because of prudence. These "safety" stops were included in the Phase II simulations. Some may have preferred to have a term for this stop that does not imply that it is optional, as the term "safety stop" might, but this is the term that has become widely used and is applied to the 3-min required stop which is required on all dives. It is not included inthe calculations, so in that sense it is indeed a "safety" stop.

SeaRat

PS, this is a 126 page paper, very, very extensively documented. I'd like to thank Scubadada for highlighting this paper, which I have never seen before. I was looking through my manuals, through old issues of NAUI News, and had not come up with anything useful for this discussion. I did find my nots from the NAUI High Altitude Diving Conference in 1974, but we did not discuss the safety stop in that forum.

 

[Scared Silly]

So... @Scared Silly

What is the answer? You could reveal it under a spoiler like @Pedro Burrito does

Who says I know the answer ???

 

[scubadada]

Who says I know the answer ???

Ha, I assumed you did, as it was your question to divert us away from all the talk on Covid-19 and politics. It's a good question

 

[Khrissi]

You are just not patient enough. Give them another five minutes and they will be arguing over the middle name of the dog that ate out of the dumpster at the LA YMCA and the influence it had on the process of Laminating dive tables which resulted in the adoption of the color scheme that was adopted by the printer of the first edition of the Science of Scuba diving and resulted in a font choice that limited the number of columns that ended up in only being able to go to 130’ on a page. Hence the 130’ limit.

...... is the Right answer K

 

[Khrissi]

I believe the wheel came out in 88, I think the PADI tables came out 79-80

No mate, I think you will find the wheel was around in Roman times, I Definately saw it in Ben Hur , and that cannot be wrong. So abt 2000 yrs ago give or take an inch. K

 

[shurite7]

I think I found the article. I'm downloading it now.

Development and validation of no-stop decompression procedures for recreational diving: the DSAT recreational dive planner..

The link is dead. Can you provide an active one?

 

[NothingClever]

You are just not patient enough. Give them another five minutes and they will be arguing over the middle name of the dog that ate out of the dumpster at the LA YMCA and the influence it had on the process of Laminating dive tables which resulted in the adoption of the color scheme that was adopted by the printer of the first edition of the Science of Scuba diving and resulted in a font choice that limited the number of columns that ended up in only being able to go to 130’ on a page. Hence the 130’ limit.

I dare say...you just captured the current spirit of Scuba Board.