Single Hose without an SPG?

[duckbill]

I hear rumors of people ascending and descending horizontally

Figures. I was taught to ascend head up, looking up, and with one arm held up toward the surface to prevent hitting my head on any obstructions and potentially knocking myself silly. Made perfect sense to me at the time. Are those horizontal guys the ones that interlace their fingers and twiddle their thumbs by their navels throughout the entire dive? That always looks odd to me.

 

[John C. Ratliff]

John, what was the rig in: Samo bagging fish in Okanawa.jpg? The bottles an valve protector remind me of some of the simi-closed rigs I saw in the diving locker but never used.

Akimbo,

That is a manifold guard we used in the USAF Pararescue for parascuba jumps. We called them "jump tanks," but they were converted 20-man life raft bottles. They had a half-inch USD double manifold, bands with a military harness. Samo was wearing ULPs, or underarm life preservers too, instead of the vest that the Navy wore. We really enjoyed those tanks, as they were much lighter than the twin 72s, and still held about 84 cubic feet of air, which was enough for our missions. The Navy really liked them for the same reason, and some were traded when overseas, from what I've heard. Anyway, we needed the manifold guard to keep parachute lines from tangling in the manifold, and possibly tearing off the on/off valve or reserve lever during our static line jumps. We even used masking tape over the manifold guard to form more of a shield for the lines as they deployed. At times, due to the turbulence of jumping out into the air stream and the prop blast of the turboprop of an HC-130 aircraft, we were blown in twisting or tumbling motions and so would not be able to control how the lines deployed.

The last photo is of our NAUI ITC class in 1972. Take a look at the snorkeling equipment. I'm in the lower right with the stripes on my wetsuit.

SeaRat

 

[John C. Ratliff]

Akimbo,

Here's one more photo, and this black and white shot I took after my own jump and was located off Okinawa in 1968. It shows a USAF Pararescueman about to land in the sea beside a one-man life raft, which was his target. This will give you and others an idea of the amount of lines on these parachutes, and the need when exiting the aircraft to have a manifold guard on the tanks.



John

 

[miked]

In 1974, my first rig (single hose) included a regulator with a built in J valve (lots of fun on a tank with its own J valve...), and the "Horsecollar " BC with built in CO2 canister to help inflate, in addition to the oral inflate.
I also had an SPG-recommended by my instructor. Some people looked at it as if it was alien technology ....

 

[Tommymac]

I started diving in 62 with an Aqua-Div Dlx. I wrote to US Divers and asked how deep I could go with it, and I think I still have the letter they send back, telling me 98' was their recommendation. I went to a Mistral and later a Swimaster single hose. Skin Diver magazine had an article about new accessories available to divers, and included the spg. I wrote Skin Diver a letter suggesting that the spg is less and accessory more like a fuel gage on an airplane. Exactly a year later there was an editorial in Skin Diver magazine which said the spg should no longer be considered an accessory. They also included my letter written a year earlier in that issue. Much on my Skin Diver magazine collection was ruined with water leaking in my basement where they were stored. I don't know what year and month the issue(s) came out. As I recall, Sportsways promoted the spg and most divers I knew called the spg a Sea-Vue gage.

 

[USdiver1]

My first regulator was a Healthways Scubair J. It had a first stage with a built in J (constant reserve) valve. I believe that it was made in 1962 or 1963. I purchased it used when I first got certified in 1977. Would have loved to have been able to afford a ScubaPro Pilot MkV, Conshelf XII or an AMF MR-12II back then, but I was a poor high school kid. The Scubair J breathed HARD, and the fact that Healthways and others built and marketed constant reserve first stages for their single (and double)hose regulators seems to point to either the early SPG was not all that reliable, or that it was not widely adopted.

 

[drbill]

Dove without an SPG on single hose for a number of years. Back then we had J-valves on tanks with a rod that you pulled down when your reg started breathing hard. It gave you a reserve supply to get to the surface (hopefully). Unfortunately, diving in kelp sometimes caused the rod to get pulled down prematurely. Not having an SPG back in the 60s and 70s was a PITA for sure. I don't think I got my first SPG until the 80s.

 

[John C. Ratliff]

I wasn't around, but from my understanding of the progression of regulator development, the single hose predated the SPG...

As near as I can tell the single hose and SPG came out in the US market about the same time. US Divers 1957 catalog had both but both were pretty lame. The SPG attached to the valve rather than the regulator. Single hose regulators and SPGs were widely available by 1960, though not in wide use in my area.

… It existed in the early 60's but wasn't really common until the mid-late 70's, so divers used J-valves and were expected to have some relative idea of how much gas they had. So I guess you should add single hose/j valve in the mix, and inflator hose should be around the time of the octo around 1980 ish? ….

Non-reserve K-valves outsold the reserve J-valves about 3 or 4:1 according to sales figures I remember reading in Skin Diver Magazine. That is consistent with what I saw in Northern California in the 1960s. Regulator performance at low cylinder pressures started having noticeable increased resistance around 300-500 PSI. That gave plenty of warning to leave the bottom. J-valves were a lot more expensive to buy and maintain, which is probably the main reason. For example the 1962 US Divers J-valves were $30 and the K-valve was $7.95.

The owner of Art’s Aqua Shop tried to explain that to me and my dad but dad insisted that I have a J-valve. I soon learned Art was right and never bought another J-valve for a single again. I later used J-valves on doubles since that was the only manifold available but that was even more useless. It only held back the reserve in one cylinder and equalized with the second when it was pulled. It didn’t take long before I just left the lever down all the time. Knowing that it was down was better than hoping it was still up.

Akimbo,

I think I have a definitive statement from Jon Hardy, NAUI's General Manager, in NAUI NEWS for May of 1976.

...The use of submersible pressure gauges and/or reserve warning devices are REQUIRED for all OPEN WATER SCUBA training. The use of submersible pressure gauges for all scuba diving is strongly recommended. (emphasis included for clarity only.)...
NAUI NEWS, May 1976, page 12

Concerning the use of J-valves, a lot of us used double tanks, and reversed the valve (see the photo below of a Navy UDT/SEAL using this technique). This prevented the inadvertent tripping of the reserve lever, and I still use this on my double tanks equipped with this reserve manifold (see the image of my PJ tanks below). So tbone1004 was pretty much right on in his memory of the use of the SPG. I also am including some screen shots from a GoPro video I made of yesterday's dive in the Clackamas River, where I used my PJ tanks, my USD Overpressure Breathing single stage regulator (predecessor of the Mistral) and reversed J-valve with an SPG on a Banjo fitting (the regulator was modified to include a long yolk, and much longer hoses than the original regulator, but retained the hose-within-a-hose venturi concept).

SeaRat

 

[Akimbo]

Akimbo,

I think I have a definitive statement from Jon Hardy, NAUI's General Manager, in NAUI NEWS for May of 1976...

I rarely saw a double hose, new J-valve, or a single hose without an SPG by 1976, outside of the Navy. Maybe SPGs weren't universal but they were definitely dominant by then.

 

[John C. Ratliff]

I helped Midge Cramer, a NAUI dive instructor, with his class in 1976 (I think). He taught that class with the Healthways SCUBA Deluxe double hose regulator. I don't recall whether we had J-valves or used the restrictor orifice in the regulator, but it was pretty simply. We took a trip to Hawaii diving, and the students brought their own gear. Below are some of the photos I took of that trip. There was a mix of divers using and not using the SPG.

SeaRat