Panic!!!

[boulderjohn]

Perhaps my criticism is misplaced. The courses I taught under the NAUI banner were designed for a particular sub-set of the diving community.

Here is another bit from history.

NAUI had a set of standards that students needed to meet, but they allowed instructors to add to that set of standards. This was common for classes taught in universities, because the courses had way more time than was needed to become a basic scuba diver. NAUI focused its efforts on university instruction for a very practical reason. Its financing system was based on what founder Al Tillman had learned when he directed the taxpayer supported program through Los Angeles County. They were a non-profit that survived by donations in lieu of taxes. For example, Skin Diver magazine supported them for their first years. Bill High loaned them $200,000 (IIRC) one year to help make ends meet. Focusing on university classes seemed ideal because the instructor got paid by the school using the tuition the students paid that would have gone to another physical education class if not for scuba--so it was essentially free to the student, and the instructors were paid by someone else. In the long run it turned out to be a bad idea, because it very much limited its potential student pool.

 

[Mantaray95616]

Assuming you are diving within no decompression limits, then there is a chance (but only a chance) that you will get decompression sickness. That is not a desirable, but it is much more desirable than drowning. It is also far more desirable than a lung overexpansion injury, which is what will almost certainly happen if you hold your breath.

I will put these two together to explain a big difference in modern (for the last few decades, really) instruction and instruction back in your day.

Today nearly all agencies use a variation of mastery learning, which does not use the traditional idea of failing. In traditional learning, students are taught for a specified period of time and then given a grade compared to a standard. It could be a failing grade. In mastery learning, students are taught for however long it takes for them to meet the standard. In theory, no student ever fails, but that does not mean they all pass. They may decide that they are having enough trouble that they don't want to continue. Some students will meet standards very quickly. Some will take much longer. It doesn't matter. They get the same certification.

Hey, if you look back on my posts, the original courses , before NAUI was created, were based on students mastering skills at their own pace and then being tested. Maybe failing is the wrong word; but if a student is unable to complete a necessary skill before the course ends (they can make as many attempts as they like) they cannot be certified. They are still welcome to re-enroll in later courses. What's so different between our two methologies?

In the two specific cases I brought up it was a matter of judgement. In my opinion neither of them would ever be comfortable in an underwater environment and I acted accordingly and with regret.

 

[Mantaray95616]

Hey, if you look back on my posts, the original courses , before NAUI was created, were based on students mastering skills at their own pace and then being tested. Maybe failing is the wrong word; but if a student is unable to complete a necessary skill before the course ends (they can make as many attempts as they like) they cannot be certified. They are still welcome to re-enroll in later courses. What's so different between our two methologies?

In the two specific cases I brought up it was a matter of judgement. In my opinion neither of them would ever be comfortable in an underwater environment and I acted accordingly and with regret.

I haven't yet got theknack of selectong quotes.

I have two comments regarding bouyant and free ascents.

At the depths you would be normally diving, fully emptying your lungs is unnecessary and can make the ascent more stessfull. Maintain an open airway and let change in ambient pressure do its work of expelling excess air. I am only making an assumption ; but my guess is that ejecting from a submarine, pressurized to 1 atm, into an 11 atm environment ( a 10 fold increase) requires the maximum lung capacity to be available.

The second is regarding the Royal Navy's use of oxygen. Pure oxygen was used by the navy's frogmen in rebreather sets (no bubbles) to avoid detection.

Pure oxygen becomes TOXIC at a depth of 33 Ft. A pure air mixture becomes toxic when the partial pressure of oxyen reaches 14.7 psi (165 ft). This is one of the reasons mixed gas diving evolved. The human body can tolerate a certain amount of toxicity.