Why two hoses originally?

[YankDownUnder]

There were a number of escape apparatus for submarine use, but they were rebreathers, not open circuit air, like the MSA. The American model was known as the Momsen Lung. It was charged with oxygen just before use.

The British used the Davis Submarine Escape Apparatus (DSEA) featured in the film Silent Enemy with Lawrence Harvey. It had it's own organic oxygen cylinder and could be used for shallow water swimming.

The Germans were the first with the Drager rebreather, used in U-Boats. It became the basis for the rebreather used by Hans Hass. (See: www.therebreathersite.nl) Initially the Drager rebreather was intended to walk around on the bottom, not swim. A similar rebreather of that type was the British Siebe Gorman Salvus. I have a Salvus and they are a strange rebreather with the counter lung around the neck and the rst of the device work on the hip.

The short coming was CNS poisoning, which was not understood at that time. However, it usually was not a factor, as the exposure was of such short duration.

[Fibber McGee]

Can you post pictures of the one you have? I haven't seen one...I figure that as far as WW2 stuff (and I've had a lot of it over the years) goes that the escape rebreathers would be almost as rare as rotors for an Enigma Machine.

thanks!

[capn_tucker]

Can you post pictures of the one you have? I haven't seen one...I figure that as far as WW2 stuff (and I've had a lot of it over the years) goes that the escape rebreathers would be almost as rare as rotors for an Enigma Machine.

thanks!

Actually not as rare as you might think. I've seen an entire Enigma machine for sale on eBay. The things people sell..

[Phil]

Dear YDU:
I think you may be over-simplifying when you say that EG and JYC's real contribution was the return hose. For example, the CG reg was a downstream valve system - virtually all of the other demand regs, such as the MSA 'tank escape system', the aviator's AN6004 dilutor/demand, the various firefighters air lungs, etc., were all upstream demand valves. Fine in shallow water, but NFG in deep water because of small orificing, adiabatic freeze-up, etc.
The Commeinhes units, pere et fils, were quite a different kettle of fish. I have six of them, ranging from the RC35 through the GC49. The overpressure exhaust control was/is not just a problem of mechanical adjust - it simply not possible to adjust for every position your body assumes in the course of navigating a wreck or doing work or threading your way through reef channels - it requires that you adjust your body position continuously and adjust the mask side controller as seldom as possible.Fortunately, this becomes almost automatic when you get used to using this particular style of air lung.
Gagnan was successful in eliminating the return hose by 1951/52 - but his employers didn't want to know about it! (for details see ' Emile Gagnan and the Aqua-lung' - Part 1: 1948 - 1958' Phil Nuytten Historical Diving Society - Canada, Copyright 2004) The solution was incredibly simple and quite elegant and it solved the pressure differention in BOTH off-centroid positions. That is, mouthpice below the diapphragm as well as mouthpiece above the diaphragm! Your mention of the Marne River trials notes that the reg freeflows in the heads up position - and the return hose 'fixes' that problem - but an equal problem was the hard breathing when the head was much lower thaqn the diaphragm in the head down position. Gagnan's later solution 'fixed' that also.
DoubleHosers tend to see Gagnan's contribution as primarily the CG reg and its offspring. He also developed the single stage reg with venturi - an amazing technological feat and the largest selling scuba system in the world through out the 50's and early 60's - but more importantly, Gagnan developed and patented virtually every feature that we use in single hose regulators today. From balanced 1st stages to venturi -assist 2nds - through the diaphragm exhausts, and on and on.
His crowning achievement was not the 1010 as most people think, but a single hose, fully balanced single stage regulator. The prototypes were built and tested in 1952/54 although a number of the features were built and tested previously. This reg was never built commercially and exists only as a few prototypes and incomplete ssemblies.
Whoops, pontificating again - sorry about that!
I'll finish up Part 2 one of these days - it spans the period 1957 to 1980.
Phil

[YankDownUnder]

There is no doubt that Gagnan made many interesting design inovations. It is also interesting to see how the same problems were handled differently in different places. The J valve of Gagnan's was used in Europe and the USA, while Australians inverted their tanks and decanted for more positive air management. Gagnan put the reserve on the tank, while Ted Eldred put it on the reduction valve as early as 1952. The Australians initially imported IWK tanks to replace surplus aircraft tanks. The high pressure IWKs were expensive, and when used as twins, could not compete with the steel 72, but pressure gauges became a must, as a reserve was only suitable as a back up for unmanaged air. The savings on the new tanks caused a cost when the gauge was added. However, mass production and mass appeal won out in the end. Australians fell victim to the slick advertisements which crossed the big pond.

The up stream valve appeared on the Heinke series, the Porpoise, the Scubmatic, the Dawson and the Sea Bee with superior breathing. L'Air Liquide appeared so threatened by the Porpoise that they forced the sale of Breathing Appliances in 1960, and attempted to supress the design. The Royal Australian Navy contract kept it alive for more than a decade. Ted Eldred told me he sold his first CA early in 1952. Over 12,000 were produced. I have the last Porpoise sold. I bought it in 1977. My Porpoise CA-1 and CA-2 are dated 1953 and have venturi jets. The demand valves were never changed throughout the life of the marque. The massive venturi had to be advertised as something the diver should not be afraid of. The flow was so great that trying it in a store scared off some customers.

While not the first, Jim Ager has made the single hose regulator longer than in other manufacturer in the world. He started production of the Sea Bee in 1954 and still comes to work each day. He told me a few weeks ago, that he only changed to the down stream configuration because the "politically correct" pressures from commercial cerification companies like PADI. Instuctors told students they weren't safe. His Sea Bee has never had a failure in either configuration and is prefered by commercial divers here, since the disappearance of Porpoise.

I must admit I have not dived any of these units beyond 200 feet. I began diving them in 1959, and I have never seen a problem with the tilt valves. My Heinke MkIII still breathes better than any of my Royal Mistrals and there is nothing to adjust or to 'tune'.

[crimediver]

Can you post pictures of the one you have? I haven't seen one...I figure that as far as WW2 stuff (and I've had a lot of it over the years) goes that the escape rebreathers would be almost as rare as rotors for an Enigma Machine.

thanks!

Actually not as rare as you might think. I've seen an entire Enigma machine for sale on eBay. The things people sell..

There are a few Enigmas floating around. One interesting fact about the Enigma is that there were a lot of them produced for businesses before the war to allow for secure communications to prevent commercial espionage. The Nazis later adapted the Enigma for wartime communications. A lot of the Enigmas offered for sale are the civilian versions. I met one guy who owned a dive shop in the Outer Banks who located the Enigma machine of the U-85. He had it restored. He told me it was valued at $150,000.00. Nice souvenir !

[Fibber McGee]

A nice find indeed. I read a paper a while back that described the mathematical theory behind the four rotor enigma machine and gave an expression of the number of possibilities of keys and results...the number is rather huge and gives an idea of what the code breakers at Bletchly were up against. Rather interesting.

Maybe the enigma was a bad analogy....how about graphite vanes from a V-2 rocket? (of which I have only seen in person one for sale)

...but I digress.......going back, does anyone have any photographs of some of the submarine escape devices? ...if any of you have one, have you ever tried using it underwater? ...if so, how well do they breathe? I suspect that other than training, the only time anyone would likely have used one was in a real emergency so the finer points of comfort, breathing ease, etc were probably ignored at that moment.

[Phil]

There is no doubt that Gagnan made many interesting design inovations. It is also interesting to see how the same problems were handled differently in different places. The J valve of Gagnan's was used in Europe and the USA, while Australians inverted their tanks and decanted for more positive air management. Gagnan put the reserve on the tank, while Ted Eldred put it on the reduction valve as early as 1952. The Australians initially imported IWK tanks to replace surplus aircraft tanks. The high pressure IWKs were expensive, and when used as twins, could not compete with the steel 72, but pressure gauges became a must, as a reserve was only suitable as a back up for unmanaged air. The savings on the new tanks caused a cost when the gauge was added. However, mass production and mass appeal won out in the end. Australians fell victim to the slick advertisements which crossed the big pond.

series, the Porpoise, the Scubmatic, the Dawson and the Sea Bee with superior breathing. L'Air Liquide appeared so threatened by the Porpoise that they forced the sale of Breathing Appliances in 1960, and attempted to supress the design. The Royal Australian Navy contract kept it alive for more than a decade. Ted Eldred told me he sold his first CA early in 1952. Over 12,000 were produced. I have the last Porpoise sold. I bought it in 1977. My Porpoise CA-1 and CA-2 are dated 1953 and have venturi jets. The demand valves were never changed throughout the life of the marque. The massive venturi had to be advertised as something the diver should not be afraid of. The flow was so great that trying it in a store scared off some customers.

While not the first, Jim Ager has made the single hose regulator longer than in other manufacturer in the world. He started production of the Sea Bee in 1954 and still comes to work each day. He told me a few weeks ago, that he only changed to the down stream configuration because the "politically correct" pressures from commercial cerification companies like PADI. Instuctors told students they weren't safe. His Sea Bee has never had a failure in either configuration and is prefered by commercial divers here, since the disappearance of Porpoise.

I must admit I have not dived any of these units beyond 200 feet. I began diving them in 1959, and I have never seen a problem with the tilt valves. My Heinke MkIII still breathes better than any of my Royal Mistrals and there is nothing to adjust or to 'tune'.

Dear YDU:
Great to see that there are hosers that are huge fans of their 'homies' - just as I am of mine!
The 'Porpoise' total sales of 12,000 is quite an impressive number - relative to the population of Australia. Seems as though a lot of the Oz systems were heavily influenced by various models of the 'EssGee' (Seibe Gorman's under-license version of the Spiro CG45) but certainly some were unique. As a point of interest, the top two hose regulator production numbers for the Aire Liquide/Spiro plant and their international licensees (SG/USD/A-L Nihon/etc.,) were in the late 60's and are reported to have exceeded 10,000 units per month!
I was interested in your comments about the tilt valve regs - we ran a lot of breathing machine tests of early upstreamers (Rose Aviation/ Waterlung A/Scott/etc.) that seemed to correspond closely with field experience - that is, the tilt valves had low cracking pressures and easy breathing in shallow water but by their design limitations tended to bottom out during heavy exertion at any significant depth. There seems to be little controversy about the ultimate breather - for both low cracking and LPM flow rate - being the combined downstream valve/ venturi assist.
i.e. a properly set up RAM or Trieste or other similar regs.
(A 'sleeper' used for deep water was the long lever Normalair(Yeovill, U.K) tilt valve single stage set - when combined with a first stage reducer!)
Discussions of fave reg designs could go on indefinitely - but gas physics are the same the world over - orifices are holes that go sonic at accurately predictable differential pressures- flow rates and cracking pressures are accurately measurable- and so on.

Still and all, always nice to see somebody fervently rooting for their local team - particularly if they are a transplant to the area!

Phil