Doff and don vintage rig

[simonbeans]

Probably sounding stupid here, but you keep refering to youself as being a TA. I think you might mean teaching assistant (known today maybe as dive masters) or do you mean tight asses?

 

[rx7diver]

Probably sounding stupid here, but you keep refering to youself as being a TA. I think you might mean teaching assistant (known today maybe as dive masters) or do you mean tight asses?

Simonbeans,

Lol. Well, some of my work colleagues might think the latter applies!

Yes, here "TA" = "Teaching Assistant." My open water course (in summer 1986) was a university PE course. I took it when I was a grad student (much to the angst of my doctoral committee members). Several of us alums of the course continued to assist with the course, gratis, in subsequent semesters. We assisted with the pool portion, the lecture portion, and/or the open water portion--depending. The instructor/professor referred to us as TA's. Most of us didn't pursue "professional" certifications (e.g., dive master, assistant instructor, instructor, etc.), though a few of us did; I never did.

Safe Diving,

rx7diver

 

[Paladin]

I'm not sure what you mean. I wrote: "A steel 72 + DH eventually will be slightly positive in fresh water." I meant exactly what I wrote. The 72's we used then were the "newer" chromoly type (rather than the "older" carbon steel type, if this makes a difference). Several of our required pool skills were "circuits" which involved having a diver sit for a while on the bottom of the shallow part of the pool, breathing off of a steel 72 + DH which he/she held onto (i.e., didn't wear) until he handed off the cylinder to an arriving diver. These were very long-duration skills, typically 45 minutes or longer, involving multiple divers. We TA's would switch in a fresh 72 + DH when the one the diver was breathing off of began "floating", bottom-up on the surface. This was our signal that the cylinder had less than approximately 200 psig remaining in it.

Safe Diving,

rx7diver

The only steel 72s that I have ever encountered that were positively buoyant when empty were the old Walter Kidde tanks. All the others were neutral or slightly negative when empty. My youngest son has a WK tank and it tends to float, valve down, when nearly empty.

 

[Luis H]

"A steel 72 will be slightly positive in fresh water." You might want to rethink that.

My first reaction was to agree with you, but then I remember swimming laps in the pool with an empty tank. Our only flotation device was the empty tank… It wasn’t much of a flotation device, but it didn’t sink either. If I remember correctly, they were just barely floated without a regulator.

The best technique was not to wear it on your back, but to take it off and push in a stream lined configuration it in front of you. If you wore it then you were going to be lifting it out of the water.

When we swam these laps we started with mask, fins, and snorkel. Then we did it without the fins (some laps with only one fin), then with fins and mask, but no snorkel, and last with fins and snorkel, but no mask. At the time I determine that if I had to loose something, on the surface the mask was the least important. Having the snorkel and fins was the best way to get home.

This was the method we used in the late 1950s and early 1960s before the "invention" of the backpack,

I have a back-plate from the 50’s and I have seen others. By the 60’s there were plenty of different backpacks. I am not even talking about home-made units and war surplus backpacks that were converted. We have seen plenty of those. I know they where not in the catalogs, but there is plenty of vintage stuff that was not in any catalog.

In the 1960 Aqua Lung catalog is showing a “bac-pac” and no single tank harness. In 1961 they are showing two different types of “bac-pac” and no single tank harness.




Added:
I just checked the in the water weight measurements that I have taken of some of my steel 72. I have measured nine so far using a digital scale with a line to hang the tanks in the water. I measured in fresh water and convert the data to salt water (as needed).

Out of the 9 tank, 2 will never float in fresh water. The two are Norris (one will be basically neutral, or within 0.1 Lb from being neutral). The other seven, 4 are PST and 3 are Norris. The PST tend to be a bit lighter. Most of them will float up to 2 Lb (with the valve, but no regulator).

 

[Paladin]

My first reaction was to agree with you, but then I remember swimming laps in the pool with an empty tank. Our only flotation device was the empty tank… It wasn’t much of a flotation device, but it didn’t sink either. If I remember correctly, they were just barely floated without a regulator.

The best technique was not to wear it on your back, but to take it off and push in a stream lined configuration it in front of you. If you wore it then you were going to be lifting it out of the water.

When we swam these laps we started with mask, fins, and snorkel. Then we did it without the fins (some laps with only one fin), then with fins and mask, but no snorkel, and last with fins and snorkel, but no mask. At the time I determine that if I had to loose something, on the surface the mask was the least important. Having the snorkel and fins was the best way to get home.




I have a back-plate from the 50’s and I have seen others. By the 60’s there were plenty of different backpacks. I am not even talking about home-made units and war surplus backpacks that were converted. We have seen plenty of those. I know they where not in the catalogs, but there is plenty of vintage stuff that was not in any catalog.

In the 1960 Aqua Lung catalog is showing a “bac-pac” and no single tank harness. In 1961 they are showing two different types of “bac-pac” and no single tank harness.




Added:
I just checked the in the water weight measurements that I have taken of some of my steel 72. I have measured nine so far using a digital scale with a line to hang the tanks in the water. I measured in fresh water and convert the data to salt water (as needed).

Out of the 9 tank, 2 will never float in fresh water. The two are Norris (one will be basically neutral, or within 0.1 Lb from being neutral). The other seven, 4 are PST and 3 are Norris. The PST tend to be a bit lighter. Most of them will float up to 2 Lb (with the valve, but no regulator).

Hmm. With the exception of the one WK, all of the steel 72s we have here are Norris. The only PSTs we have are LP 95s. Might explain why all but the WK sink when empty.

 

[Nemrod]

A steel 72 with regulator will not be positive in fresh water even if nearly empty.

As to bubbles streaming out between breaths and all of that, whatever. If I breathed as much as most people and divers I would be hyperventilating. It is normal for me not to breath constantly. If some newbie were to flip my lips he/she might get a lesson in mask recovery.

The video seems to demonstrate a very nicely done doff and don. The method is as taught during the day. There are other ways to do it but that is the exact method I was taught.

N

 

[simonbeans]

As always I need to clarify my apparently "too general" statement. Best the line should be said, "

This was the method [MANY OF US] used in the late 1950s and early 1960s before the "invention" of the backpack THAT UTILIZED THE WIDE STRAPS WITHOUT STERNUM AND CROTCH STAPS, YOU KNOW THE ONES THAT EVERYBODY SEEMS TO USE THAT WERE CONTOURED SHAPED OR OF HOLLOW PLASTIC CONSTRUCTION WITH THE BUILT IN HANDLE."
YES, USD, DACOR, AND HEALTHWAYS ETC., HAD A BACKPACK OR SOME SORT OF BACK PLATE, BUT THERE WERE SOME OF US WHO USED THE TANK WITH SIMPLE HARNESS AS DEPICTED IN THE VIDEO.

Let's see if I can get a contrary view to this. The sun will appear to rise somewhere in the eastern sky, somewhere tomorrow.​

 

[rx7diver]

... I remember swimming laps in the pool with an empty tank. Our only flotation device was the empty tank… It wasn’t much of a flotation device, but it didn’t sink either. If I remember correctly, they were just barely floated without a regulator.

The best technique was not to wear it on your back, but to take it off and push in a stream lined configuration it in front of you. If you wore it then you were going to be lifting it out of the water.

When we swam these laps we started with mask, fins, and snorkel. Then we did it without the fins (some laps with only one fin), then with fins and mask, but no snorkel, and last with fins and snorkel, but no mask. At the time I determine that if I had to loose something, on the surface the mask was the least important. Having the snorkel and fins was the best way to get home.

[HIJACK]
Luis,

This is a neat training skill! Do you recommend that these types of training skills be resurrected for training divers interested in diving using the various vintage approaches and various vintage gear?

Maybe a new thread can be begun to list and describe these types of training skills.

Safe Diving,

rx7diver
[/HIJACK]

 

[captain]

A steel 72 with regulator will not be positive in fresh water even if nearly empty.

N

That has always been my experience. They will float with no regulator and all tank buoyancy specifications are for the tank alone not with a regulator mounted.

 

[rx7diver]

Nemrod, Captain:

Unfortunately, I can't tell you for certain what specific make of 72's (nor even what type of metal DH's) we used during my long-ago experiences I recounted above--though I'm almost certain they were PST cylinders. I'm wondering, though, if the fact that the divers were actually breathing on the DH regulators at the time (you know, so one or both hoses were filled with air at the time) played a role?

Safe Diving,

rx7diver