Question for old timers - NAUI OW class, early 1970s

[ScubaDadThree]

An SSI instructor did this at the University of Alabama just a few years ago, and a student did die--held his breath on ascent.

In a pool? Even 10 ft on a full breath of Compressed Air will not cause DCS unless the lungs are weak to begin with. That should have been discovered in the medical exam prior to starting the course.

 

[boulderjohn]

NAUI (emphasizes education and safety) was the only game in town back then. Then PADI (a.k.a. Put Another Dollar In) was created followed by the rest of the profit seekers.

Here is the actual story of the origin of the two agencies:

NAUI was formed in 1965 under the leadership (primarily) of Al Tillman (NAUI instructor #1), who had been the director of the Los Angeles County program, which was taxpayer supported. Because of that, he could not expand beyond the taxpayer base. He tried to follow that taxpayer model, replying on a number of handouts and donations to support NAUI's existence. For example, they used donated office space within a skin diving magazine office. They lost that when the magazine was bought out. They relied on university classes primarily for students, meaning that the classes were paid for with tuition money, and the instructors were mostly on the university payroll. That system proved to be very limiting, and they were in constant financial trouble, at one time staying in existence only with a loan from Bill High, later the founder of PSI.

As an attempt to stay within their financial means, in 1965 they decided to withdraw from their national efforts and focus on California. In doing so, they canceled a major instructor training session scheduled for Chicago, and the Chicago branch of NAUI, already at odds with them for other reasons, formed their own agency, calling it PADI. They immediately instituted a major change they had previously called for by looking for students primarily through the stores selling dive equipment rather than universities.

The sources for this is the same History of NAUI document I have cited several times already.

 

[boulderjohn]

In a pool? Even 10 ft on a full breath of Compressed Air will not cause DCS unless the lungs are weak to begin with. That should have been discovered in the medical exam prior to starting the course.

Yes it was in a pool, although it was deeper than 10 feet. Ten feet is much more than enough of an ascent to do lung damage.

 

[ScubaDadThree]

An SSI instructor did this at the University of Alabama just a few years ago, and a student did die--held his breath on ascent.

The typical pool is 10 ft deep. Even a full breath of compressed air will only stretch the lungs and not cause a fatal embolism without a pre-existing condition that should have been a contraindication for Scuba Diving. While a bad practice that should be discouraged it should not be fatal in a pool. Something else was going on.

 

[ScubaDadThree]

Since you are a Technical Instructor, can you recommend another Tech Diving Instructor in NC? Having a picture of me standing on the Flight Deck of the USS Oriskany (off shore Pensacola, FL) is on my bucket list and will require Trimix because of the depth (145 fsw).

 

[boulderjohn]

The typical pool is 10 ft deep. Even a full breath of compressed air will only stretch the lungs and not cause a fatal embolism without a pre-existing condition that should have been a contraindication for Scuba Diving. While a bad practice that should be discouraged it should not be fatal in a pool. Something else was going on.

I will do the calculations for sea level.

Assume one lungful as our starting volume, and assume 10 feet of fresh water (1.3 ATA) for our starting pressure. That means the lungs, starting full at the bottom of the pool, will expand to 1.3 times their original size upon reaching the surface. That is nearly a third. If a full set of lungs expands by a third, you can be sure there will be some damage.

At my altitude, it will expand pretty well over a third.

 

[boulderjohn]

Since you are a Technical Instructor, can you recommend another Tech Diving Instructor in NC? Having a picture of me standing on the Flight Deck of the USS Oriskany (off shore Pensacola, FL) is on my bucket list and will require Trimix because of the depth (145 fsw).

It will only require trimix if you train through one of the few agencies that require trimix at that depth--most don't. Most tech agencies will let you do that dive on air or a light nitrox mix.

I don't believe I know any tech instructors in that area.

 

[ScubaDadThree]

As University of Alabama student did indeed die doing the exercise perhaps 7-8 years ago. The instructor was SSI. The exercise was not then (and is not now) part of the SSI curriculum, so the instructor added it on her own. She was not physically supervising the incident when it happened. I never heard the results of the lawsuit, but I imagine the insurance company settled very high and very fast.

A couple decades ago a landmark study of student incidents during training revealed that breath holding on ascent, leading to embolism, was the number one cause of student injuries and fatalities. The prime culprit was the CESA. As a result, PADI and most other agencies adopted extremely strict rules on how the CESA must be done, with the instructor very much in control of the situation at all times and ready to intervene if the student is detected holding the breath. I do not know for sure, but I suspect that is when the doff and don left most instructional practices. The student does not have to hold the breath long during an ascent to cause a problem.

I certainly don't know the rules of all agencies, but for most of the mainstream ones, if the instructor is doing the doff and don, it is in addition to the curriculum and against the wishes of the agency. If there were to be an accident, the instructor would have a tough time defending it in court.

Once upon a time (late 1970's. Jacques Cousteau was middle aged), I took a NAUI Basic course at a suburban Chicago college. During the doff and don in a 10 ft pool the Instructor was on the bottom watching us equip ourselves. We had to give him the OK sign when we thought we were done, followed by his OK when he agreed. Then, while hanging on to us he pointed up and blew bubbles. Only when we blew bubbles too did he let go. The Assistant(s) were at the surface corralling the "guppies" ( we weren't certified yet). That should be the standard practice regardless of agency. There are old divers (hello), there are bold divers. There are no old, bold divers. I weep for the future complacency, but Darwin will prevail.

 

[ScubaDadThree]

It will only require trimix if you train through one of the few agencies that require trimix at that depth--most don't. Most tech agencies will let you do that dive on air or a light nitrox mix.

I don't believe I know any tech instructors in that area.

At my age DCS is easy to get, so I would prefer to eliminate it altogether, hence, Trimix. Thanks.

 

[boulderjohn]

At my age DCS is easy to get, so I would prefer to eliminate it altogether, hence, Trimix. Thanks.

Although trimix will give you less nitrogen, you introduce helium, which also needs to be accounted for in terms of decompression. I just ran two dive profiles through multi-deco using the Buhlmann ZHL-16-C algorithm, one using nitrox 25 and one using trimix 21/35. Since at the level of training required to do that dive agencies normally limit you to one deco gas, I used only oxygen for the plans. The two plans came out almost identical, with exactly the same run time.

For DCS planning, the primary safety factors are the deco profile and the gas (or gases) used for that purpose. It is more important than the gas you breathe during the bottom portion of the dive. Tech students often have a hard time understanding this.

The most important reason to use trimix on a 145 foot dive is to avoid narcosis. There are a few agencies that require trimix at that depth, and narcosis, not DCS, is the reason for it.