Training then. This is what was state of the art advice in 1968

[Rich Keller]

Scubapro tried to improve on the basic J valve with their DCAR version. The Depth Compensating Adjustable Reserve valve would increase the reserve the deeper you went, you could set the reserve from 300 to 600 psi and there was a version were the lever was on the divers side of the valve making it easier to reach and less likely to be bumped down during the dive. It also had a pressure gauge built into the back of the valve.

 

[icechip]

When I first certified back in 1979 with YMCA, the course took weeks with lots of pool time and book work. The first few pool times were nothing but swimming/getting-comfortable-in-the-water skills. Like when the instructor dumped golf balls into the deep end and we started from the shallow end going underwater to collect as many balls as we could on one breath of air. Then it was a few pool sessions of nothing but skin diving skills. In the later scuba classes we had to jump in with all the gear in our arms and then put it on. We swam lots of lengths while buddy breathing (I was wicked psyched as I got paired with the hottie in the class). Had to master the dive tables and then of course we went through the gauntlet where we swam along while the instructor and/or assistants knocked our masks off, turned off our air, etc. Now when I got re-certified a couple of years ago, the training was pretty streamlined and kind of left me longing for the more thorough experience I remembered from before.

 

[AfterDark]

Well, now they have yoke vs DIN. Today you can go on line and find a buddy if you want on Craig's List or SB. Tragically, the mindset by the time I started diving was that if you didn't have a buddy (even a crappy insta-buddy) was that you were going to turn into a pumpkin upon touching the water. I missed out on a lot of good diving because of the dogma of the day said if you didn't have a buddy YOU WERE GOING TO BE PULLLED DEAD FROM THE WATER....

The net has probably done as much to improve diving as the SPG did, maybe more...

---------- Post added April 27th, 2014 at 06:12 AM ----------

I think we had better basic training back in 1980 (when I was certified) because we really were not likely to go and collect certification cards like people do today, courses were built around a bunch of pool time to learn the basic skills and here is a lot of theory about how to plan a dive safely. Oh, and now we'll scare the crap out of you by making you practice the dive tables... Better know those inside and out (mistakes on those can really make you die...). with all the pool time we also spent a lot of time actually getting trained to dive with a buddy, so you had real buddy skills.

I always thought that buddy stuff was over rated mainly because of the lack of real rescue skills taught during training even back when training was months long. Long ago I asked myself, aside from a second air supply just what was one of the guys I dived with going to be able to do to help me? The answer came back as probably not much. I paid my money it was time to take my chances. One day no buddies were available to dive so I made a solo dive or more accurately put went diving alone. No redundant anything for a long time, just good planning sometimes helped by dumb luck. Miss out on diving?!? I rather BE PULLLED DEAD FROM THE WATER!

---------- Post added April 27th, 2014 at 10:27 AM ----------

Scubapro tried to improve on the basic J valve with their DCAR version. The Depth Compensating Adjustable Reserve valve would increase the reserve the deeper you went, you could set the reserve from 300 to 600 psi and there was a version were the lever was on the divers side of the valve making it easier to reach and less likely to be bumped down during the dive. It also had a pressure gauge built into the back of the valve.

View attachment 182827View attachment 182828View attachment 182829View attachment 182830

I still have one that works and doesn't leak. It's in the Afterdark diving museum in my cellar along with a bacpac like one the picture.

 

[Rich Keller]

I still have one that works and doesn't leak. It's in the Afterdark diving museum in my cellar along with a bacpac like one the picture.

Mine works, has no leaks, on a steel 72 from 1965 with the original backpack and still in service today.

 

[maniago]

Wow. Even the physics were different back then. Nowadays we have tanks that don't compress the air with depth and only have to contend with the pressure of the water column on our chests.

Huh? How exactly has tank technology changed?

 

[jamiep3]

I know that I have surfaced several times in conditions which warranted having a decent reserve. I can blow through a few hundred psi easily in bad surface conditions getting away from reefs or helping people on to boats. I think people that consider 500psi a "waste" simply haven't dived enough.

EDIT: I forgot to log out of Jude's account. This post comes from Supergaijin

In those days, the mind set was that you wouldn't "waste" tank air on the surface, that's what a snorkel was for. I can remeber backrolling in with my snorkel in my mouth, clearing it, and waiting for the group to be ready before switching to my Reg. Same thing at end of dive, as soon as I was on the surface, switch back to snorkel. These days, I rarely even carry a snorkel.

When I first certified back in 1979 with YMCA, the course took weeks with lots of pool time and book work. The first few pool times were nothing but swimming/getting-comfortable-in-the-water skills. Like when the instructor dumped golf balls into the deep end and we started from the shallow end going underwater to collect as many balls as we could on one breath of air. Then it was a few pool sessions of nothing but skin diving skills. In the later scuba classes we had to jump in with all the gear in our arms and then put it on. We swam lots of lengths while buddy breathing (I was wicked psyched as I got paired with the hottie in the class). Had to master the dive tables and then of course we went through the gauntlet where we swam along while the instructor and/or assistants knocked our masks off, turned off our air, etc. Now when I got re-certified a couple of years ago, the training was pretty streamlined and kind of left me longing for the more thorough experience I remembered from before.

I had pretty much the same experience in 1978, in my college SCUBA class. I didn't have a SPG, but I did have may Dad's Calypso J. I re-certified about twelve years ago, after a long lay off. I finally "learned" Buddy Breathing again last year, in a Deco class. Times have changed.

 

[Ricky B]

Huh? How exactly has tank technology changed?

It hasn't. The comment was sarcasm directed at the text in the OP (which was quoting a book from the 1960's):

When at last the air pressure in the cylinder becomes almost equal with the water pressure surrounding it, it becomes impossible to breathe. But the moment the diver begins his ascent towards the surface, the air in the tank expands and provides him with a few more breaths, which are adequate to get him safely to the surface.