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

[ScubaDadThree]

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.

I had narcosis at 105 ft. in a Blue hole in Florida. That was why our Instructor took us there. So it would happen again on the Big O. Trimix would make the dive much more enjoyable.

 

[boulderjohn]

I had narcosis at 105 ft. in a Blue hole in Florida. That was why our Instructor took us there. So it would happen again on the Big O. Trimix would make the dive much more enjoyable.

Then that is what you want.

 

[Sam Miller III]

It is important to practice skills - all skills - especially emergency skills under controlled conditions in shallow water under supervision to insure that the practice is a perfect practice, since only perfect practice makes perfect.

I recall my training instructor during the Korean war who stated "When a pilot looses his airplane he is what is known as an infantryman, when he looses his pistol he is what is known as a prisoner of war"

Appling this to diving....

When a diver looses his fins -- they are what is known as a swimmer -- If they can swim !

When he looses his mask he is what is known as is a blind swimmer --If they can swim !

When a diver develops a hole in the BC and looses buoyancy - they are a sinking swimmer -- If they can swim !

When a diver becomes entangled UW and can't do a ditch -- They are known as a dead diver.
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I began UW instruction after I was separated from the USAF at the Long Beach California YMCA . All who signed up for the classes were water people -- everything was easy for them; every thing was fun for them. They performed all the exercises I could ask of them.

The students and the courses I taught during these years were the best I ever experienced.

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About 1963 or 1964 I created and documented a number of new and exciting training exercises for the LA Co UW programs some were accepted some tossed aside.

The same time frame I created a diver instructor classification system . It was rejected by LA Co , some years later NAUI also rejected it . Around 1973 after the establishment of PADI I was informed but never verified that NAUI instructor Dennis Graver was hired by PADI and took my charts with him -- this gave John the idea of step instruction with always a carrot in front of the diver.

For this effort I was presented with the first LA Co "Out standing contributions to UW instruction"

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[boulderjohn]

When a diver becomes entangled UW and can't do a ditch -- They are known as a dead diver.

I should clarify that the phrase "ditch and don" is used differently by different people to refer to different skills.

One example is what is still done by every OW certification agency I know. The diver removes the scuba unit while while wearing all other equipment and then replaces it without every losing contact with it.

In the example that was referenced with the student who died, the student takes all equipment off at the bottom of the pool, swims to the surface without it, swims back down to it, and puts it back on.

As I said, the first of these is still required by every agency I know, but the second is not allowed by most agencies today.

 

[scubadada]

I should clarify that the phrase "ditch and don" is used differently by different people to refer to different skills.

One example is what is still done by every OW certification agency I know. The diver removes the scuba unit while while wearing all other equipment and then replaces it without every losing contact with it.

In the example that was referenced with the student who died, the student takes all equipment off at the bottom of the pool, swims to the surface without it, swims back down to it, and puts it back on.

As I said, the first of these is still required by every agency I know, but the second is not allowed by most agencies today.

We did the latter during my 1970 LA County course, several times.

 

[tr3a]

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.

Every thing I have read in the last 50 years says 3-5 ft of water is enough to pop a full lung. I would not want to test that

 

[vincent54]

We did the doff and don 1976, NAUI. Lee Duhaime was our instructor. Awesome teacher. We always had a buddy assist for the free ascents making sure we blew out on the way up. I remember the instructor telling us a 4 foot change in pressure above 10 feet could cause lung damage. I've survived since with his advice. Cheers

 

[boulderjohn]

I remember the instructor telling us a 4 foot change in pressure above 10 feet could cause lung damage.

In a breath-holding ascent from 4 feet in fresh water, the air in the lungs will expand nearly 12%. If your lungs are full to start with, that can do some damage.

Here is something to think about. If you are in 4 feet of water, you cannot inhale from a tube extending to the surface--the water pressure is too great.

 

[RikTikTavi]

I did my NAUI course in '74, and became an Instructor in '78. When I took the course, we did that "doff and done". We also did it "blacked out" for a little extra challenge. I don't know if it was mandatory or not, but by the time I was teaching it was not. However, most students were able to do it, and it was a real confidence builder.

We also did things like jumping off a diving board with all of our gear bundled and in our arms, including air turned off. The trick was to hit the bottom of the pool and reassemble you gear. All good fun.

I have head stories of NAUI ITCs in Canada where candidates did a similar exercise but jumped off a railway bridge, dropped 15' or so into a river and reassembled gear. This was in Peterborough, ON. I suspect it's true.

I never heard of anyone dying while doing any of these skills, but I think they were a fantastic way to build confidence, although the practical uses were minimal!

When I was teaching, the course was 8 - 12 weeks long, and included as many as 8 or 9 OW dives, including a night dive. Folks knew how to dive at the end of it. These days, it seems that the main purpose of an OW I course is to lay the groundwork for the 47 courses yet to come... :-(

-- Disagree on the 'limit use'. If you are on the boat and her folks come back unexpectedly, being able to grab all your gear and jump was a great asset! Very much agree that being able to do that was a great confidence builder.
- RikTikTavi

 

[Diver-Drex]

In '84 we did ditch and don at the surface and pool bottom. Also swam laps buddy breathing. The final pool session was lights out in the building and the instructor swam around pulling off masks and regs, shutting off air and knocking into us.
We also did a free ascent from around 30' or 40' during one of the check out dives. Not a CESA. Ditched gear on the bottom and headed for the surface yelling the whole time to vent expanding air. I was 13 when I took that course.