Submersible Pressure Gauge (SPG)

[agilis]

The thing is, back in the 70s and before, there was no internet. Information disseminated slowly, and only through select and limited channels.

I don't remember being told about SPGs until about 1974, when I bought one. I don't remember seeing them in dive shops here on the East Coast until that point, and I don't think I saw other divers using them.

Back in those days I read Skin Diver Magazine pretty religiously, and I don't remember any articles about SPGs. Maybe there were, but if so I didn't catch that issue. Certainly there was no big publicity splash. I have a few old Skin Diver magazines I've saved for various reasons, from 1959 and the early 60s, and I don't think SPGs are mentioned prominently. I'll have to look closer at some of the little ads.

These days most of my local NJ diving is late summer, mid 70s F, in inlets and around jetties. Primarily Gulf Stream stray tropical fish collecting and sight-seeing. I use only a plastic back pack; no BC, an old weight belt, an ancient wrist mount combination depth gauge and compass -- pretty much exactly what I used 40+ years ago, the same items, in fact, including my old Mark V. No safety second either because almost all my dives are solo. I was diving solo from the first, and still greatly prefer doing it that way. It's part of streamlining, in a way. I definitely do use an SPG, though.

With all the walls, boulders, monofilament, pilings and other structure, an SPG beats having to reach behind my back every few minutes to make sure the j valve push rod is in its up position. I have a couple of J valves in my kit, two lovely old Dacors with the knurled knob. Maybe I'll set one up for this summer, for old time's sake.

 

[iain/hsm]

We in the UK had a number of variants of submersible pressure gauges so its hard to tell which one you Yankee lot copied from us first, or where to start. I guess the Royal Navy being the clearest datable entry point of reference.

The Royal Navy diving manual dated 1964 replacing the 1956 manual shows the SDDE (Surface Demand Diving System ) a 55 msw twin 3300psi cylinder unit that had a small 2 inch submersible gauge fitted to the back of the rig (for filling) but as you couldn't see it underwater I guess it may not strictly count.

Trials of a 'feeler' Pin type tactile submersible gauge began in 1960, even a three pin and a three button lever type also a double ended bellows design all allowed a tactile indication of pressure in "black" water.
It should also be made clear in UK diving back then was using an independent twin with a "heard to equalise" principle. When approaching empty in the 1st primary cylinder an increase in breathing resistance was felt then the second (full) cylinder was opened and decanted into the first, this gave a 50% reserve and you did this twice before surfacing.
On the SDDE unit this was a single lever you pulled down to operate and on waiting for the noise of the cylinder equalising to finish re sealed the 2nd cylinder valve on release, (there were no independent pillar valve on the rig just a single central filling valve manifold with the filling gauge)

Again "Black" water was the norm for design so little incentive for a dial.

The nearest rig we had to a scuba rig was called the Swimmer Air Breathing Apparatus (SABA) so not sure if this counts.
If you want the first referenced submersible dial pressure gauge then its 1st February 1938 and the Siebe Gorman Proto MarkIV a diving version of the earlier 1914 mine rescue and fire fighter rebreather.
A time when you lot had Woodrow Wilson, Wagon Wheels and the temperance movement. Iain Middlebrook

 

[agilis]

Nothing counts unless it is easily readable by the submerged diver. Anything fixed immovably on the first stage, or anything not part of a demand regulator is not in it at all.

We may have had some dismal types back then, but you lot had to deal with Douglas Haig, Johnny French, Marmite, Chip Butty, Charlie V.F. Townshend, Amritsar, and Thomas Crapper's bizarre contraptions.

 

[danvolker]

The thing is, back in the 70s and before, there was no internet. Information disseminated slowly, and only through select and limited channels.

I don't remember being told about SPGs until about 1974, when I bought one. I don't remember seeing them in dive shops here on the East Coast until that point, and I don't think I saw other divers using them.

Back in those days I read Skin Diver Magazine pretty religiously, and I don't remember any articles about SPGs. Maybe there were, but if so I didn't catch that issue. Certainly there was no big publicity splash. I have a few old Skin Diver magazines I've saved for various reasons, from 1959 and the early 60s, and I don't think SPGs are mentioned prominently. I'll have to look closer at some of the little ads.

These days most of my local NJ diving is late summer, mid 70s F, in inlets and around jetties. Primarily Gulf Stream stray tropical fish collecting and sight-seeing. I use only a plastic back pack; no BC, an old weight belt, an ancient wrist mount combination depth gauge and compass -- pretty much exactly what I used 40+ years ago, the same items, in fact, including my old Mark V. No safety second either because almost all my dives are solo. I was diving solo from the first, and still greatly prefer doing it that way. It's part of streamlining, in a way. I definitely do use an SPG, though.

With all the walls, boulders, monofilament, pilings and other structure, an SPG beats having to reach behind my back every few minutes to make sure the j valve push rod is in its up position. I have a couple of J valves in my kit, two lovely old Dacors with the knurled knob. Maybe I'll set one up for this summer, for old time's sake.

Have to agree....I think Sam is going for a much earlier market inception point, but I think the reality was that NO ONE in the existing Diving Community, was aware of the pressure guages untill sometime in the later 70's....
Throughout the 60's, I read every issue of Ocean Realm ( was an awesome magazine, well beyond Nat Geo in quality), and most likely most issues of Skin Diver......As I indicated earlier, the FIRST I ever saw or heard of this was in 76, and this was a novelty at that time.

I wonder HOW they got actual MARKET PENETRATION when it finally did take off....maybe it was "an idea whose time had come"..or maybe dive shops just figured it was something they could talk every customer they had, into buying...kind of the way they are trying today with split fins and rebreathers

Sam, what was the critical point/date you believe the pressure gauge actually became known to the dive market? What was the technique for the penetration?

 

[Akimbo]

Have to agree....I think Sam is going for a much earlier market inception point, but I think the reality was that NO ONE in the existing Diving Community, was aware of the pressure guages untill sometime in the later 70's....

Almost everyone I dove with was using a single hose and SPG by the late 1960s, except in the Navy. Double hoses were the exception in the areas of California I traveled in.

 

[Sam Miller III]

Dan,

Go back to your earlier SDMs. Check the advertisements.

You will discover the introduction of the American SPG and others predates the ones from jolly old foggy England.

The American SPG was a viable product which was marketed by reputable company and used within all levels of the diving community. As with all innovation's it had it's initial design defects and soon was set on the shelf waiting for technology to catch up.

SDM


I am surprised that Net Doc who attended my lecture "Way Before Cousteau...." at "The SCUBA Show in June of last year has not chimed in- I covered SPG as an ancillary part of the lecture.

 

[agilis]

Almost everyone I dove with was using a single hose and SPG by the late 1960s, except in the Navy. Double hoses were the exception in the areas of California I traveled in.

Interesting. By the late 60s/ early 70s most divers I saw here on the NJ/NY area and in Florida were using single hose regulators with J valves. SPGs may have been widely used in California, but somehow I don't remember them in local dive shops or mentioned in magazine articles. I don't remember seeing anyone using an SPG back then.

When I found out about them in the early/mid 70s I assumed they were a relatively new thing. Otherwise, why no front page publicity in dive magazines? Was there a huge unsold stock of jvalves that had to be sold before publicizing SPGs? I was out of the country for a year during those distant days, but still. I'd really like to know what the situation was. I've read some California based divers who say they did not see them until about the same time I did. Others say they were in common use in the late 60s. Very strange.

 

[scubadada]

As per my post #13, I bought my first SPG in SoCal in 1972. I was in a minority for several years but by the mid 70s and onward they became increasingly common. SPGs seemed universal, or nearly so, by 1980

 

[DaleC]

Before my time but I do routinely dive with J valves or the style of pressure gauge displayed in the USD catalogs from 1957-1974 (hose entering the back). Though at first one had to drill their own manifold for installation. Originally labeled See Sea, then then Sea Div. In 1973 the pressure gauge was sold as the UDT 2in1 unit (pressure and depth). 1974 is the first year the modern pressure gauge is pictured in USD catalogs (hose entering bottom), attached to a UDS system (which I also have, though in 1975 it was relabeled the UDS-1).

FWIW, the first duel primary/octo reg set was pictured in the 1973 issue.

 

[raftingtigger]

Certified in 1971 in San Mateo, CA. SPGs were available but really expensive. My parents and I (14 years old) didn't trust a J-valve. So I bought the just introduced ScubaPro regulator that had a low pressure audio alarm on it (Mark VII). Later I got a SPG when they were more common. FWIW, the 2nd stage (109A) is still my primary and preferred regulator. My first depth gauge was a capillary one. Still have both the Mark VII and the depth gauge.