chris hecker:
I have talked to my dad about his experences diving before technology. When figuring out buoyancy, you should be just about neutral at surface, taking a little effort to get under. This way when you start running low on air, it will naturally start to lift you to the surface. He said the idea is, if you are out of air, it should be impossible to break the surface and go under.( this is how they knew the tank was low without a guage! ) Seems interesting, but I like to know how much air I have!!
Chris,
Your Dad is right, if you are not wearing an exposure suit.
DA Aquamaster has a very good post above, and all that he stated is correct.
I would only add that with a wet suit, we weighted ourselves for the depth we were going to, which may mean that we started out on the surface a bit light (buoyant). One alternatative I used at times in a fresh water lake was to remove my weight belt totally and put it onto a look in an anchor line, swim around weightless (the wet suit at about 30 feet in frosh water has lost almost all its buoyancy). When I came to the ascent, I would go up the anchor line, and put my weight belt back on before surfacing.
If you are using a dry suit (Aquala, for instance), it could always be inflated with some air. This was either through the hood (through the mask skirt), or by putting on an inflator. I did this, and will include one photo of that suit from 1974 in this post. Note that in the photo, I'm using a double hose regulator (AMF Trieste II), with an SPG and an octopus. I also have an oral inflation/deflation hose I put into the dry suit, and a power inflator. On top of that, I was also wearing a Dacor CO2 vest.
We played around with a lot of different BC concepts in the 1970s. I had a wet suit with a bladder built into it (an inverted "U" in the back of the suit) built by Bill Herter. At first, it was oral inflation, and then Bill Herter (who designed and built some of the first BCs) went to power inflation. Bill built a vest out of neoprene, and I demonstrated it at IQ6 (I believe) in 1974. In 1978, Scubapro (who was there) came out with their "Stabilizing Jacket." Bill built me a custom wet suit about then with probably the best BC concept ever for a wet suit. It was a suit with the whole back of it as a sandwich of 1/8 inch neoprene, becoming a bladder built into the back of the wet suit. It was warm, and very streamlined--and very labor intensive. Bill Herter, "Deep Sea Bill" from Newport, Oregon, retired in the late 1970s, somewhat bitter for not getting credit for developing many BC designs. His retirement card said, "Bill Herter, dive shop owner, retired; wet suit designer, retired; commercial diver, retired; Bill Herter, just plain tired."
I think the bottom line here is that you don't have to dive without buoyance compensation devices to be diving vintage equipment (double hose regs).
SeaRat