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

[John C. Ratliff]

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

Try this again. I got into the Rubicon Research Repository page. Scroll down to the links, and either open the link on the right or download it on the left (actually both links are downloads).

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

Take a look, as it's really a comprehensive paper, one that I have yet to fully digest.

SeaRat

 

[NAM001]

I dont have a source to cite but I assume it is set by the following. All limits rooted on survival of any rec diver at any level.

The average rec diver does not have severe narcosis shallower than that depth.. major driving aspect.
Complying with ascent rates, safety stop and reserve gas at end for dive sets hard restrictions on depth when gas consumption and supply is the primary limitation of bottom time
NDL being a large limiting factor when DECO is not part of the definition of a rec diver.
Square dives profiles create the worst condition when it comes to probably deco. Square dives are often done.
RECREATIONAL Dive training does not include the skills to go deeper

I think this question is very much related to why OW divers are limited to 60 ft.

 

[shurite7]

Try this again. I got into the Rubicon Research Repository page. Scroll down to the links, and either open the link on the right or download it on the left (actually both links are downloads).
SeaRat

Got it, hanks! I completely forgot about this paper. I read it a long time ago. Time to read it again.

 

[dmaziuk]

Take a look, as it's really a comprehensive paper, one that I have yet to fully digest.

The primer on statistics behind the M-values is great too. "DCS is not an accident" and "reliable over safe" should be on OW exam IMO.

 

[tursiops]

From PADI's Encyclopedia of Recreational Diving, digital edition, Chapter 5:

So, there is PADI's answer to the OP's question.

 

[scubadada]

From PADI's Encyclopedia of Recreational Diving, digital edition, Chapter 5:
View attachment 583850

So, there is PADI's answer to the OP's question.

So this section is discussing narcosisis, not all the reasons that the rec limit ended up being 130 ft. I'm reasonably sure that the Navy tables, short deco time at the depth. increased gas consumption at the depth, and narcosis, all played a role in this ending up being the established rec limit.

In my 1970 LA County course. I was told to limit my depth to about 130 ft due to very short deco time and gas time. Of course, we used Navy tables. I don't recall a discussion around nitrogen narcosis, but, then again, that was 50 years ago

 

[tursiops]

So this section is discussing narcosisis, not all the reasons that the rec limit ended up being 130 ft.

I don't agree. The statement highlighted in yellow is quite unequivocal....it is stated as "the" reason for the 130-ft limit, along with small NDLs.

 

[scubadada]

I would imagine this was written from a contemporary perspective, believe what you believe, I know better from the old days, seems like you should too.

 

[tursiops]

I would imagine this was written from a contemporary perspective, believe what you believe, I know better from the old days, seems like you should too.

We may be talking about different things.
I am talking about PADI's reasoning to put in a 130 ft limit.
I think you are talking about there being a time when there was no limit other than the 190 ft NDL tables of the Navy, plus limited gas supplies in a 72 cuft tank. What is not clear is when it shifted, but I think it IS clear why. If narcosis is the primary reason -- and that's what PADI says -- then it should be easier to find out when that happened.

 

[scubadada]

So, PADI established their rec limit I 1966 or later. I think the rec limit was already in effect, for all the reasons I listed. No big deal