First BC in 1968?

[AfterDark]

How much pressure was the Dacor Nautilus rated for (internal and external)? It has been a while, but I believe they were blow molded polyethylene and since they weren’t very symmetrical (pressure vessel-wise) I can’t imagine that they would take much external pressure.

They were ambient. It took on water for ballast and expelled the water for buoyancy. The top valve would also vent if the internal pressure got too high. It had a neat diaphram gizmo on the inflator hose that reacted to ambient pressure for slight depth changes venting air or water as needed. It really was ahead of it's time.

 

[John C. Ratliff]

The Dacor Nautilus had a regulator which kept the system at ambient pressure when descending, or a valve on the bottom could be opened to keep it ambient. This valve had to be opened to change the amount of water in the chamber, then closed to maintain the buoyancy. Upon ascending, it would start venting with about a 5 psig differential (about 10 feet of ascent in fresh water from a depth of 22 feet).

I would add that Dacor required each person buying this unit to do through a formal training session (both classroom and in-water) in order to complete the purchase (when it was new), and that each unit is serial numbered.

SeaRat

 

[AfterDark]

I bought mine used and was handed a manual.:shocked2:

 

[Diver0001]

I noticed this ad on the back inside cover of the October 1968 Skin Diver Magazine the other day. This is the first device on market I can recall that was intended as a Buoyancy Compensator rather than an emergency floatation device that could be inflated at depth like the Bouée Fenzy.

View attachment 105052

One of these is also on E-bay, thought his link won’t last forever:

1968 SCUBA EQUALIZER SAFTBALLAST DIVING SCUBA DIVER AD | eBay

Can anyone think of an earlier BC, home-brew or on the market?

I would suggest first trying to verify the authenticity of this picture.

What I'm seeing here is a regulator that would appear to have 3 LP ports, an HP port and no J-valve on either the tank or the regulator itself. All of those things would have been highly irregular in 1968.

As for the "ballast tanks"....it's an interesting concept. It would appear to be a device to regulate the diver's buoyancy by changing the weight instead of the volume (the way a submarine works). In theory it could work but I've never heard of or seen anything like it.... that said, I've only been diving since the early 80's so maybe....

personally, looking at the picture, it looks more like an april-fools joke than anything they would have had in 1968.

R..

 

[Sam Miller III]

I would suggest first trying to verify the authenticity of this picture.

What I'm seeing here is a regulator that would appear to have 3 LP ports, an HP port and no J-valve on either the tank or the regulator itself. All of those things would have been highly irregular in 1968.

As for the "ballast tanks"....it's an interesting concept. It would appear to be a device to regulate the diver's buoyancy by changing the weight instead of the volume (the way a submarine works). In theory it could work but I've never heard of or seen anything like it.... that said, I've only been diving since the early 80's so maybe....

personally, looking at the picture, it looks more like an april-fools joke than anything they would have had in 1968.

R..

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Good gosh! another one--I wasn't around therefore; I suspose, I think, I believe, I was told...

It is a real picture from Skin Diver Magazine.

SDM

 

[Akimbo]

I would suggest first trying to verify the authenticity of this picture....

I’m not sure what you mean my authenticity? Somebody spent some serious money to place a four-color ad on the back inside cover. Based on other posts, some of these units have survived. The fact that nothing like it is on the market today speaks volumes about the mechanics. However, the concept has flourished. I think the significance is the advertised intent more than the form.

…What I'm seeing here is a regulator that would appear to have 3 LP ports, an HP port and no J-valve on either the tank or the regulator itself. All of those things would have been highly irregular in 1968...

I wondered about that myself. I can’t tell from the photo if the first stage feeds both plastic cylinders or if there is some sort of valve out of view and two LP hoses feed the tanks. I’m wouldn’t be surprised if this photo was of a prototype rather than a production model since the practice endures today.

Non-reserve/K-valves dominated sales in my area even in the early 1960, let alone by 68. It was very unusual for single hose regulators to not also be equipped with a pressure gauge (my area). Also the unbalanced first stages of the era gave plenty of warning of low tank pressure — as they do today. All these factors combined with the high cost and low dependability made J-valves under-sell K-valves maybe by 3-1 (observation, not a stat).

Interesting story: I was 11 in 1962 and went into the dive shop with my dad to buy gear and sign up for the course. The owner of the shop, a shed in his side yard really, tried to steer us away from reserve valves but my non-diving father and I didn’t like the idea. Both of us watched lots of Sea Hunt and the reserve valve was used on most every episode! The second tank I bought had a K-valve. :blush:

 

[Diver0001]

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Good gosh! another one--I wasn't around therefore; I suspose, I think, I believe, I was told...

It is a real picture from Skin Diver Magazine.

SDM

At least I was being honest. I started diving in the early 80's with gear that manufactured in 1972 and as I said it's hard to imagine, given what I saw at the time, that this gear was widely available.

You are, however, correct in pointing out, as did I, that I've only been diving since the early 80's so it's possible that I'm not aware of some developments.

Regardless of my limited experience, I'm intrigued by the idea of a weight displacement BCD. I wasn't aware that anything like this had ever been developed and it's very interesting to realize that it's not a new concept.

R..

 

[Diver0001]

I’m not sure what you mean my authenticity? Somebody spent some serious money to place a four-color ad on the back inside cover. Based on other posts, some of these units have survived. The fact that nothing like it is in the market today speaks volumes about the mechanics. However, the concept has flourished. I think the significance is the advertised intent more than the form.



I wondered about that myself. I can’t tell from the photo if the first stage feeds both plastic cylinders or if there is some sort of valve out of view and two LP hoses feed the tanks. I’m wouldn’t be surprised if this photo was of a prototype rather than a production model since the practice endures today.

Non-reserve/K-valves dominated sales in my area even in the early 1960, let alone by 68. It was very unusual for single hose regulators to not also be equipped with a pressure gauge (my area). Also the unbalanced first stages of the era gave plenty of warning of low tank pressure — as they do today. All these factors combined with the high cost and low dependability made J-valves under-sell K-valves maybe by 3-1 (observation, not a stat).

Interesting story: I was 11 in 1962 and went into the dive shop with my dad to buy gear and sign up for the course. The owner of the shop, a shed in his side yard really, tried to steer us away from reserve valves but my non-diving father and I didn’t like the idea. Both of us watched lots of Sea Hunt and the reserve valve was used on most every episode! The second tank I bought had a K-valve. :blush:

I think I'll start following this forum. I've had a lot of assumptions about older gear based on my early experiences that evidently were not accurate.

Thx to all.

R..

 

[John C. Ratliff]

I was in the USAF from 1967 to 1971, got out to go to college, and in 1973 became a NAUI Instructor. The period right around this time was a period of a lot of experimentation in buoyancy control. I wrote about it at IQ6, and had done some experimentation. I would not be surprised if this BC was from the cave diving community, as they were some of the first to experiment with it, and some used chlorox bottles for buoyancy control. I'll write more about this tomorrow, but this probably was a legitimate product.

 

[Thalassamania]

Here is a thread on developing an automatic BC that touches on some of these design issues. That is probably why I reacted to this ad.

http://www.scubaboard.com/forums/research-development/397397-patent-pending-number-________.html

I wrote this in the Patent Pending thread, but that seems to be a bit off the beaten track, so I'll post it here too:

We built such a system for an autonomous ROV. It had a pressure sensor as well as two tilt sensors coupled to the controllers of four rather small reversible motors. Each motor caused a piston to move up and down in a cylinder on a threaded shaft. One side of the piston pressed against "captured" air, the other side was flooded and water was free to move in and out. If you needed to increase the buoyancy of the system you told the motors to push water out of the tube, permitting the air chamber to expand, to decrease buoyancy you reversed the motors and compressed the air.

There was a down control, an up control and a "stay here" button. It was also possible to tilt the vehicle in any direction while maintaining depth or changing depth. All run with a Z80, using machine language, writing the code on the bare metal, like real men.

I always thought it would have been fun to take two of the tubes and strap them on each side of my MK-15, only maintaining the "stay here - on" or "stay here - off" functionality.