Official vintage diving instruction?

[iPutty]

I never thought about putting all that info in a spreadsheet, but in the water, the buoyancy characteristics of all my vintage gear combinations is within a pretty narrow range anyway. I mark the tanks with a grease pencil for a few depth ranges, fresh or salt water and that's about it.

You really can't get it exactly perfect anyway, since an empty tank weighs less than a full one, and different depths obviously compress a wet suit differently. If I know I can ascend along a line, I'll go ahead and weight myself neutral for the depth I'm diving, especially for shallow dives.

But, that's not really ideal, since it can be a real problem for a deep dive if you miss the line, as controlling even a marginally buoyant ascent can be dangerous. Alternatively, I deal with being a little heavy on the bottom, which I find very uncomfortable.

As everyone here knows, buoyancy control without a BC, to a large extent means breath control. Teaching students anything but maintaining normal breathing patterns runs the very real risk of air expansion injury. As an example, students ask me all the time how they can tell if they're holding "half" a breath.

 

[Thalassamania]

I never thought about putting all that info in a spreadsheet, but in the water, the buoyancy characteristics of all my vintage gear combinations is within a pretty narrow range anyway. I mark the tanks with a grease pencil for a few depth ranges, fresh or salt water and that's about it.

The range is rather narrow, the biggest problem is wetsuits made of different materials.

You really can't get it exactly perfect anyway, since an empty tank weighs less than a full one, and different depths obviously compress a wet suit differently. If I know I can ascend along a line, I'll go ahead and weight myself neutral for the depth I'm diving, especially for shallow dives.

You can swing the shift of a single vintage cylinder on your lungs.

But, that's not really ideal, since it can be a real problem for a deep dive if you miss the line, as controlling even a marginally buoyant ascent can be dangerous. Alternatively, I deal with being a little heavy on the bottom, which I find very uncomfortable.

I don't recommend vintage gear for a deep dive. Deep dives involve enough serious problems to not complicate them with the buoyancy issues of massive wetsuit crush.

As everyone here knows, buoyancy control without a BC, to a large extent means breath control. Teaching students anything but maintaining normal breathing patterns runs the very real risk of air expansion injury. As an example, students ask me all the time how they can tell if they're holding "half" a breath.

Yes, it means breath control, somehow we did manage to teach that for many decades with a significant problem. Are todays' students somehow inherently less capable?

 

[iPutty]

The range is rather narrow, the biggest problem is wetsuits made of different materials.
You can swing the shift of a single vintage cylinder on your lungs.
I don't recommend vintage gear for a deep dive. Deep dives involve enough serious problems to not complicate them with the buoyancy issues of massive wetsuit crush.
Yes, it means breath control, somehow we did manage to teach that for many decades with a significant problem. Are todays' students somehow inherently less capable?

Wetsuits are made of foam neoprene--have been for a long time. Since you find it necessary to contradict every point I make, I don't really have much else to say. However, maybe you should go back and study your physics. The most "massive" amount your wetsuit "crushes" is nearest the surface. The difference in volume change at say, going from 5ATM to 6, compared to the first 33 feet is almost insignificant.

There were divers in the 50's and 60's routinely making dives beyond 200 feet on air, calculating multiple decompression stops using Navy tables. Are divers less capable of that today?

I like the idea of teaching a vintage scuba class, so I jumped into your forum. Rather than comment on a single one of my points about creating, conducting and marketing such a class, I've merely been picked apart for stating that PADI does not teach divers to overweight. Yes, I am a PADI instructor. I have all of the materials and the only goal stated anywhere in the curriculum is neutral buoyancy. Instructors that overweight students are in violations of standards.

I love diving with vintage gear just like everyone here. But, to get into religious arguments over something we basically agree on is ridiculous.

 

[Thalassamania]

You're awfully sensitive and I don't quite know about what, different neoprenes crush differently. Take a "modern" ultraflex neoprene to say 100 feet and you'll be glued to the bottom. Do the same with old Kirkale or Rubatex and you'll be a few lbs overweight ... it makes a huge difference.

I hate to tell you but I was one of those divers in the sixties making dives to 200 feet with a RUBATEX wetsuit. What we did is weight for the depth, fight our way down and use a decompression bar (with seat belts) on the way up. Check Lee Somers' Univ. of Michigan Research Divers Manual, reproduced in it is a graph, like the one I used, of weight needed vs. depth. If you want to learn to dive like we did back in the day you need realize what is reality rather than assume that if it is not in the PADI encyclopedia it a religious argument.

 

[John C. Ratliff]

Years ago, I wrote an article for NAUI News about buoyancy control. In it, I mentioned a test dive I did at altitude in Clear Lake, Oregon (fresh water). I went to 35 feet, took off me weight belt, and swam around in a full Farmer John wet suit (known in that time as a 1/4 inch wet suit) perfectly neutral. From that point, I could go to any depth without any buoyancy compensation, and stay completely neutral. So iPutty does have a point. We used to weight ourselves for the depth we were going to, and then not worry about the weights at all. Now, we have BCs, which must be continually monitored with depth due to Boyle's Law (remember that one?). If we dive to 99 feet (30 meters), we have one-quarter the original volume. If I started out with 25 pounds of weight, and lost it all, I would have in my BC the equivalent of 100 pounds of buoyancy in that BC at the surface (bled off, though).

By the way, "deep diving" used to mean diving between 60 feet and 130 feet, which was considered the maximum safe depth for sport divers. Beyond that, more measures than the sport diver had available were needed.

One of the thoughts I've had for a very long time is that the decision to dive deep, and do decompression diving, should follow the decision to have procured (through a club, charter, etc.) a recompression chamber. Cousteau's divers in the 1950s had a recompression chamber immediately available on the Calypso, and in fact one of the first scenes of The Silent World was of Cousteau sticking one of his divers into the chamber while the rest of the crew went off to eat lobster, some of which he had caught. We now have these fancy diving protocols, with "Tech Divers" putting on up to four tanks to dive and decompress with under 200 feet. And we have continuing mishaps (such as this incident) and death ,such as are detailed in Bernie Chowdhury's book, The Last Dive, A Father and Son's Fatal Descent into the Ocean's Depths. What a different picture of diving to the public than we had in the 1950s-1980s with Cousteau!

SeaRat

 

[Eric Sedletzky]

You're awfully sensitive and I don't quite know about what, different neoprenes crush differently. Take a "modern" ultraflex neoprene to say 100 feet and you'll be glued to the bottom. Do the same with old Kirkale or Rubatex and you'll be a few lbs overweight ... it makes a huge difference.

I hate to tell you but I was one of those divers in the sixties making dives to 200 feet with a RUBATEX wetsuit. What we did is weight for the depth, fight our way down and use a decompression bar (with seat belts) on the way up. Check Lee Somers' Univ. of Michigan Research Divers Manual, reproduced in it is a graph, like the one I used, of weight needed vs. depth. If you want to learn to dive like we did back in the day you need realize what is reality rather than assume that if it is not in the PADI encyclopedia it a religious argument.

I'm using a suit right now that's actually denser than Rubatex G-231. I also have a G-231 suit hanging in my closet next to this other 7 mil, but the Rubatex is a little spongier than the other suit, and Rubatex is no slouch when it comes to crush resistance.

This other material is hard to move in but it changes very little in the top 33 foot critical area.
They don't make G231 anymore I found out, but this other stuff is a commercial grade material and is actually higher performance and more crush resistant than G-231.

Different grades of neoprenes and wetsuits in general would have to be covered in class because for anybody serious about diving in thicker wetsuits with no BC, the spongy crap they make common off the rack suits out of these days won't work.

I weight myself really light sometimes and end up carrying around different rocks as the tank emties out and I'm coming back in to shallower water.

 

[Thalassamania]

What is the material and where can I get some? I make my own suits and will need a new one soon.

 

[Eric Sedletzky]

What is the material and where can I get some? I make my own suits and will need a new one soon.

Thal,

Call Don at M&B wetsuits in Long Beach (562) 422-3493
He is the one that made the suit for me. He makes suits for all the commercial divers.
Tell him Eric Sedletzky Sent you and you want to know where you can get the super dense material that he made the 7 mil out of for me.
The urchin divers were getting suits made from that stuff because it was about as close to G-231 that they could get.

There might be some different stuff available now. He sent me some samples of a Chinese material that was actually pretty reasonable and it mimicked G-231 pretty close. The only thing is I don't know if anything is going to have the same retraction factor that Rubatex used to have. That stuff was indestructable.

Call him and ask him. That's where I would start.

Good luck, and let me know how things turn out.

 

[Thalassamania]

Thanks.

 

[iPutty]

If you want to learn to dive like we did back in the day you need realize what is reality rather than assume that if it is not in the PADI encyclopedia it a religious argument.

Sensitive? I don't think so. Yes, I understand quite clearly about characteristics of neoprene. None of that has much to do with the viability of a vintage scuba class.

I don't need to learn to dive like you. If you knew my background, you'd keep the insults to yourself. For the record, I don't think you've been anywhere near 200 feet.