Submersible Pressure Gauge (SPG)

[Sam Miller III]

Fellows Lets get back on the Subject =="SUBMERSIBLE PRESSURE GAUGES"

If you like begin another thread on price comparison
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The post was to demonstrate to those who loudly proclaim that "I began diving there was no SPG!" that there were SPGs --The American version was introduced in 1954 and the French (European) introduced in 1930s.


A question for RMBoulder, who has a good handle on published history and others who are internet savvy is:

"What was the design defect of the MarMac SPG that made it so dangerous ?"

I suspect inquiring minds will want to know ...

The Marmac had three design defects they were;
1.
2.
3.

Any guesses before Ryan swoops in with the answers???


SDM

 

[DaleC]

Sam, without even doing any research that one is easy. But I as an engineer those things come to mind quickly for me (usually) so I am going to leave it for others to figure out. But there is a post in another forum about some who could not get any relief when he did something silly with a first stage and a SPG.

"What was the design defect of the MarMac SPG that made it so dangerous ?"

Any guesses before Ryan swoops in with the answers???
SDM

I'm not sure but SS reminded me of something I did once. Namely, hooking up a first stage to check PSI without a reg for pressure relief. Doh! I slowly cracked back the thumb screw and bled off the pressure. So.. I'm going to guess one defect was no pressure relief valve.

 

[ams511]

I think one of the problems was the thin fitting. It did not attach securely to the tank/nozzle.

 

[Sam Miller III]

DaleC

Close! Has something to do with the pressure.

SDM

 

[John C. Ratliff]

Who on this board began diving prior to the SPG introduction to the US Market?

Who on this board began diving prior to the SPG introduction to the European (world?) Market?

When did you begin your diving career?

SDM

Dr. Miller,

I haven't read through this thread yet, but decided to simply answer your first questions first.

I began diving before the SPG. I was using a Healthways SCUBA regulator, 38 cubic foot tank with a K-valve, and the restrictor orifice built into the SCUBA double hose regulator for the reserve function. That was in 1959. 'Bought the unit with money I earned picking strawberries and beans in the fields around Salem, Oregon. I dove rivers and lakes in Oregon, then went to the coast to spearfish and dive in Yaquina Bay, Oregon as well as in the Puget Sound area and Thetis Island, BC, Canada. My second unit was a Healthways Scuba Star single hose regulator, steel 72 tank and I think a K-valve, as the Scuba Star again had the restrictor orifice built into it. When I was in the USAF, we dove a single hose regulator, usually the USD Calypso, with either twin 72s or twin 40s for parascuba jumping. We really liked the twin 40s as they were light and felt nice to dive. I have a photo of them on Steven Samo in Okinawa in 1968. We had no SPGs, but used the 500 psig J-reserve in the USAF for these units. Obviously, with a twin 72 verses a twin 40, their reserves would be different in terms of breathable air after activation. I could work it out mathematically, but don't feel the need right now.

SeaRat

 

[DaleC]

I like pic #3

 

[John C. Ratliff]

Sam,

I'm going to say that the SPG you are talking about had a problem when pressurized in that it was inflexible and hard to see. It probably also had no O-ring seal to allow it to be rotated so as to be readable.

One more thing...I'm looking at my Aquamatic first stage (I have a full Aquamatic regulator too, but it's in the outside shed and it's late), and there is no HP port at all. There is only one port, and it is for the low pressure hose. That hose has a different fitting too, as it is not an O-ring fitting, but a brass-on-brass contact fitting much like the twin manifolds of that time (and some even today). So one thing holding back the SPG was that there was no provision on really old (1950s) regulators for mounting one.

The first Calypso regulator had a stem gauge, but it required a weird washer setup with the O-ring to seal the HP hole. So that would inhibit use of an SPG (although I have used the washer to mount a SPG on an Original Calypso).

Dale,

Picture #3 was also taken off Okinawa in 1968, but we were using our twin 72s with the single hose regulator when a single hose regulator had a single hose. We used USD Calypso (second generation) almost exclusively at that time, even though they had yet to be approved by the U.S. Navy Experimental Diving School (no single hose regulator was approved at that time, due to breathing characteristics--exhalation). But we were doing parascuba jumps, and the double hose regulator was too vulnerable to having the hoses ripped apart during our parachute opening, with the risers hitting things as we exited the aircraft. I've enclosed some photos of pararescuemen outfitted in various configurations of jump gear.

Note that the photos of Nick Kalmis and Little Joe Williams were taken in the 1950s, and Pararescue was using the Mistral regulator at that time. We did not await the blessings of the U.S. Navy to get better gear. By the way, they were jumping from the HU-16B Albatross, which had a "hatch" rather than a door and was notoriously hard to get out of. I had a number of jumps, including parascuba, from the HU-16, and we were thankful for the narrower tanks in the late 1960s. The photo I took below of the Albatross in the water shows the reason for the hatch rather than a door.

Note also that there are no SPGs in this gear. The less we had to tangle a parachute, the better.

SeaRat

PS--My first rig, which I described above, cost about $65 as I recall. My only income was from picking strawberries and beans. We got $0.25 per carrier, which was 8 hillocks (little boxes about 4 inches by 4 inches by 4 inches). A carrier was a wooden box with high handles that allowed these 8 little boxes to be carried in the field. We had to fill those to overflowing before turning them in too. I picked probably an average of 12-16 carriers a day, so that was $3-4/day. So that was between sixteen days of picking strawberries and 22 days of picking strawberries to get that gear. We were on our knees all day picking these berries (about 9 AM to 3 PM, taken by bus to the fields). I wore out the knees of several jeans that way; today kids buy jeans already worn, but we earned our worn-out jeans. I got the scuba unit used, a 38 cubic foot tank...yellow...and had my choice between a USD Mistral, a Dacor Dial-a-Breath, and the Healthways SCUBA, and I choose the Healthways SCUBA. It had blue hoses, and breathed really smoothly on the surface. The Mistral and Dacor would also have cost more, as I recall. This probably started me on the road to getting used gear too!

 

[drbill]

Sam, I think the point was that many of us DID begin diving before SPGs were commonly available and used. I certainly don't remember seeing one for quite some time. The fact that some had been made is not an issue, the issue should better be asked when did they become commonly used. Heck I never used a BCD until 1989... 27 years after I did my first dive. And even on that dive (it was required equipment by the Cousteau team I dove with), the BCD failed due to auto-inflation and I had to disconnect it and dive without it.

Fellows Lets get back on the Subject =="SUBMERSIBLE PRESSURE GAUGES"

If you like begin another thread on price comparison
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The post was to demonstrate to those who loudly proclaim that "I began diving there was no SPG!" that there were SPGs --The American version was introduced in 1954 and the French (European) introduced in 1930s.

 

[DaleC]

Great pics and memories John. In pic #4, is the diver wearing shark repellant on his ankle by the knife?

I also picked strawberries as one of my first jobs.

 

[agilis]

"Commonly available" is the key question. I was certified in 1972, back when certification included many hours over several weeks, and I don't recall ever being told about SPGs. We were trained with J valve tanks. K valve tanks were mostly used with unbalanced regulators so moderate breathing restriction signaled low air. Modern SPGs don't seem to have been publicized in diving magazines until well into the 70s, and I never noticed one in any of the dive shops I frequented.

No one ever tried to sell me one, or even show me one, so I have to assume they were not commonly available, at least here in the North East, admittedly far from the epicenters of scuba activity. I bought the first SPG I saw, around 1974, a black face Scubapro in a chrome-plated case that read up to 3500 psi. I still have it and it still works fine, after several rebuilds.

Money was not an issue. I did see various gizmos that used protruding feeler gauges on the first stage, or were simply standard tank pressure gauges that were submersible but virtually unreadable by a submerged diver, but to me these were basically useless and do not constitute what I would consider a real SPG, certainly not a useful reliable SPG like the one I bought 40 years ago. Those items remind me of the late 60s Healthways Airflo regulators and their first stage tank attachment, a flawed somewhat bizarre method that seems in retrospect to have been a movement in the direction of modern DIN attachment.

The unanswered question remains. Why did so many divers remain unaware of SPGs until the early 70s? Is it because there were no really good ones until then? Was there a breakdown in marketing strategy? I know the cost was not a issue for me and for many other divers. We simply did not know they existed because our only sources of information-- magazines, dive shops, and other divers-- seem to also have been unaware of their existence.