History of 18m depth limit?

[Lorenzoid]

This is the explanation I give to my OW students, while I teach them about the tables. Dives shallower than 60 feet will tend to be limited by air, dives deeper than 60 feet will tend to be limited by NDL. The OW course tends to focus on "monitor your air, do not run out of air", while the AOW course places a greater emphasis on dive planning.

Another way to phrase it might be that 60 feet is sort of a sweet-spot for the classic recreational dive profile of two consecutive dives of 45-60 minutes on 80 cf tanks with roughly an hour surface interval between them. Limiting to 60 feet lets the average diver get the most out of this kind of diving.

 

[Bob DBF]

Those tables were not designed for recreational diving only, and they included decompression schedules. They had to follow a specific theoretical compartment to guide repetitive diving, and they chose the 120 minute compartment. That would be just fine for people doing one decompression dive a day, but it was very inconvenient for people doing shallower, NDL dives, because it led to unnecessarily long surface intervals.

The Navy tables used for recreational (OW) diving were NDL tables, same as today. The Navy Deco tables were not used until more advanced diving, what is called tech now. Basic recreational training was for NDL buddy diving, as it is today, if one did decompression dives it was in violation of their training, as it is now.

The Navy separates their NDL and Deco tables as they are different types of diving. The Navy divers I knew were NDL divers because the worked onboard ships, diving in addition to normal duties, and had minimal support.

The reason that deco was on the tables was in case one inadverdently, or due to emergency, overstayed NDL one could calculate their obligation and plan an exit strategy. The RDP has a deco contingency plan but requires a standard deco stop, regardless of the deco obligation.

Despite that, people like to claim that the OW curriculum is constantly being dumbed down. I don't know why people like to do that, but that has been true for decades and has not changed.

Through your persistence you have changed my mind on that, however most do not see the difference between theory and practice.



Bob

 

[boulderjohn]

Through your persistence you have changed my mind on that, however most do not see the difference between theory and practice.

And that is because most people do not have accurate information about either theory or practice.

Theory: What percentage of divers know the actual standards by which diving is taught today? What percentage of divers know the actual standards by which diving was taught decades ago? How many people can make any sort of intelligent comparison based on actual facts?

Practice:For more than the last decade, PADI alone has issued around 900,000 certifications worldwide per year. What percentage of those certifications does a diver see in order to judge current practices? When divers were originally certified, they saw the class in which they were certified. What percentage of the world's classes does that one class represent? Individual instructors do individual things, and their classes can vary widely, sometimes showing little relationship to the actual standards. Comparing a class you saw 20 years ago with a class you saw today and drawing a comparison is like saying you met an Australian 20 years ago who was 6-6 in height, saying you met one today who was 5-8, and concluding that Australians have lost 10 inches in height over the last 20 years.

I was certified a couple of decades ago in 2.5 days, including a 2-hour pool session and a long list of skipped standards. I did not realize that my certification did not meet standards for years, until I became a professional myself. If I were to compare the practices of today with the practices of 20 years ago, my baseline for the comparison would be that 2.5 day class.

In this History of NAUI, the authors admit that the normal NAUI practice in the 1960s of sending out certification cards when students registered for the class so that the instructor could hand them the card upon completion led to many students being certified without completing or, in some cases even taking, the class. That would be in sharp contrast to people who talk about the staggering difficulty of the classes they took at the same time.

 

[Seaweed Doc]

An old friend of mine (NAUI instructor, our institution's DSO, and formerly a volunteer at Catalina's chamber) told me the reason for switching from "60 at 60" to "50 at 60" had to do with Doppler studies (or somesuch) indicating microbubbles were forming. Hence, we sometimes called the "new" tables "no bubble tables."

Does that seem a reasonably accurate idea? Or is it an old divers' tale?

 

[dmaziuk]

On a recent trip I was shocked when a 22 year old member of the dive team suggested I should not go deeper than 18m!

I'm not sure which part of this is bleaker: that 22 year-olds can't read, or that a 22 yo who can't read can get an OW cert. You'd think they had to read and comprehend the booklet to pass the written exam...

 

[Efka76]

Hi all, does anyone remember what year PADI started the 18m depth limit for Open Water? I got certified in the 1980s and was under the impression that I was certified to 30m. Was there a change in standards at some point? On a recent trip I was shocked when a 22 year old member of the dive team suggested I should not go deeper than 18m! Thanks

Sir, it seems that you fail to understand basic concept of risk taking in diving. If you have PADI OW certification you are certified to 18 m depth limit only. If this 22 year old divemaster would take you to deeper dives and you have some issues, he cold face serous legal issues. Also, if you read DAN or DiveAssure rules, they can legally refuse paying for you medical bills if you intentionally exceed your certification limits. Now we live in the world where legal matters rule. As an example, ask yourself what would happen if you are bike racer who participated in many motor bike races but your drivers licence say that you can drive car only, and you are stopped by policy. I am 100% sure that you would get a fine for driving without appropriate license.

It is time for you to read PADI books once again and refresh your memory about current standards

 

[tursiops]

Sir, it seems that you fail to understand basic concept of risk taking in diving. If you have PADI OW certification you are certified to 18 m depth limit only. If this 22 year old divemaster would take you to deeper dives and you have some issues, he cold face serous legal issues. Also, if you read DAN or DiveAssure rules, they can legally refuse paying for you medical bills if you intentionally exceed your certification limits. Now we live in the world where legal matters rule. As an example, ask yourself what would happen if you are bike racer who participated in many motor bike races but your drivers licence say that you can drive car only, and you are stopped by policy. I am 100% sure that you would get a fine for driving without appropriate license.

It is time for you to read PADI books once again and refresh your memory about current standards

Sigh, I hope this post is a satire.
It totally confuses the difference between "certification" and "training." The OW card is a certification to 130 ft; but the training is only to 60 ft, hence the recommendation by PADI and concern by insurance companies that you not exceed your training. Get some more training, go deeper. Up to the certification limit of 130 ft. Then you need a new - technical - certification....and more training.

 

[Efka76]

Sigh, I hope this post is a satire.
It totally confuses the difference between "certification" and "training." The OW card is a certification to 130 ft; but the training is only to 60 ft, hence the recommendation by PADI and concern by insurance companies that you not exceed your training. Get some more training, go deeper. Up to the certification limit of 130 ft. Then you need a new - technical - certification....and more training.

Could you please show me official source that PADI OW card certifies diver up to 130 ft depth. I just checked PADI Open Water manual, PADI official website and have not found any mentioning that PADI OW certifies up to 130 ft depth. I really hope that you will be able to show official source in order to support your post. In opposite case I will recommend you read theory first and then comment.

 

[Efka76]

Sigh, I hope this post is a satire.
It totally confuses the difference between "certification" and "training." The OW card is a certification to 130 ft; but the training is only to 60 ft, hence the recommendation by PADI and concern by insurance companies that you not exceed your training. Get some more training, go deeper. Up to the certification limit of 130 ft. Then you need a new - technical - certification....and more training.

@tursiops I am still waiting for your source that PADI OW certification is to 130 ft. Or Master Instructor with more than 2500 dives is not able to find this source and is writing sarcastic posts without any grounds. Maybe Master Instructor needs to refresh knowledge, read PADI materials once more or ask newbies like me? Or Master trainer and greatest marine scientist is reading PADI OW book now and is afraid to loose reputation and admit that he / she was not right and does not remember even basic things about PADI OW.

 

[tursiops]

@tursiops I am still waiting for your source that PADI OW certification is to 130 ft. Or Master Instructor with more than 2500 dives is not able to find this source and is writing sarcastic posts without any grounds. Maybe Master Instructor needs to refresh knowledge, read PADI materials once more or ask newbies like me? Or Master trainer and greatest marine scientist is reading PADI OW book now and is afraid to loose reputation and admit that he / she was not right and does not remember even basic things about PADI OW.

I'll ignore your snark.

Part of the problem here is semantics. Let's distinguish between certification, qualification, license, training, and recommendation. Those words are used by different people and agencies in different ways.
I assume you agree that the accepted depth limit for recreational scuba diving is 130 ft. The OW certification ONLY says you passed an OW class in recreational diving....it is not a certification to a certain depth, it is an introductory recreational certification (130 ft) with an associated recommendation of 60 ft. maximum depth. Here is what PADI says, for example, on their website (Become a Certified Scuba Diver FAQs | PADI):
How deep do you go?
With the necessary training and experience, the limit for recreational scuba diving is 40 metres/130 feet.
Note it does NOT say "with the necessary certification, the limit...." because you already have the certification...OW. The point of the AOW and the Deep cards is to document the additional training, which is all a certification does; it documents the training that was taken. It is not a license.
The Encyclopedia of Recreational Diving says "Newly certified Advanced Open Water divers are qualified to dive deeper and in somewhat more challenging conditions than Open Water Divers." Note that it distinguishes between the certification (getting an AOW card) and the qualification that you are now trained to dive a little deeper.

There used to be a question on the PADI OW Final Exam that went something like this: "What is the depth limit for a recreational scuba diver?" The possible answers were 40 ft, 60 ft, 100 ft, 130 ft. Almost everybody got it wrong, answering "60 ft." The correct answer was "130 ft." I wish I could find a copy of that old exam but I don't seem to have it anymore.

Now, I suspect you are prepared to argue with and disbelieve anything I've said.
So why don't you contact PADI and get your own answer and present it here? You might want to pose your question as: "What is the depth to which an OW diver is certified, as opposed to the recommended maximum dive depth of 60 ft?"