Italian Frogmen (combat swimmers)

[JMBL]

Found it ! Have a look !

 

[JMBL]

Interesting. I never knew that reserve valves, or K-valves in the US, were popular outside of North America.

Reserve valve were compulsory for beginners until the early 90's in France. The use of a SPG was reserved for "1er échelon" divers (aka CMAS 2*). Can't they I was ever a big fan of those valves, only had by experiences with them... As standard working pressure for tanks was 176b at that time, if your reserve valve was faulty, things could get hairy pretty quick...

 

[Akimbo]

For anyone interested, here is a link to the book referenced in the video:
Against the Odds: Battles at Sea, 1591-1949 by Alexander McKee

@Sam Miller III also recommended this book to me:
FROGMEN FIRST BATTLES by William Schofield and P. J. Carisella

I completed four books on the UDT (US Underwater Demolition Teams) last year. It looks like I have a several more on my reading list!

 

[Angelo Farina]

Interesting. I never knew that reserve valves, or K-valves in the US, were popular outside of North America.

There was no SPG, so a reserve valve was almost mandatory. However Italian valves, invented and patented by Luigi Ferraro for the Technisub brand, were quite peculiar. They were spring loaded, so it was impossible to pull by error the rod until the pressure had dropped below the spring-calibrated pressure. In stead with american valves a common problem was to already pull the rod so when the air was finishing you did try pulling the rod but the reserve was already gone...
Here a detail of typical Technisub twin tank reserve:

 

[ginti]

There is plenty of information on Wikipedia, even in English. The history of the "Decima" and the "Gruppo Gamma" is quite interesting since many raiders popularised the sport we love. For instance, Luigi Ferraro, the guy mentioned by @Angelo Farina, was involved with Cressi and later founded Technisub.

[EDIT: I remember to have read that Ferraro is the man who sank the highest number of ships alone; not hard to believe, given the time he was active as a raider, but I don't find anymore the reference]

Interestingly, the real story goes back to the first world war—more info on wikipedia.

Regarding the equipment, unfortunately, I do not manage the references anymore, but if I recall correctly, at the very beginning, Pirelli was deeply involved. They developed a special rubber suit that allowed the raiders to have appropriate thermal protection underwater. But I am sure that @Angelo Farina knows way more than me in this regard.

 

[David Wilson]

@David Wilson can probably give us more information on the gear they used.

Everybody else contributing to the discussion so far has done a brilliant job. I would just mention the fins developed by Superga and used by the Italian combat swimmers:

As you can see, this military fin was an uncomfortable fixed-heel affair. Superga later brought out an asymmetrical version with each fin marked either "destro" (right) or "sinistro" (left) to inform the user which one belonged on which foot. This arrangement meant that the longest edge of the blade went on the outside.

Here is an image of a surviving real-life model:

I read somewhere that Luigi Ferraro, already mentioned on this thread as an outstanding member of the "Gamma" combat swimmers, designed the Cressi Rondine full-foot fin with its open toes to be the height of comfort after his feet had personally suffered from being squashed into ill-fitting Supergas during World War II.

Cressi dubbed the float valve used in their snorkels and snorkel-masks a "Gamma" valve after it was designed by Ferraro and patented:

 

[ginti]

This website has some nice piece of information:
Oxygen Rebreathers Italy

One of the links also describes the Pirelli suit that I mentioned before:
Pirelli Diving Suit

however, in this forum, a guy says that the Pirelli suit was developed later in the war and before they were using a different suit:
Italian Pirelli Diving Suit

 

[ginti]

Other info here:
Underwater killer frogs

A suit called "Belloni suit" was first used; the name is from the inventor, Angelo Belloni, another raider.

The ARO (Auto-Respiratore a Ossigeno) was developed by Pirelli. I bet prof @Angelo Farina has some stories to tell us about it.

 

[Akimbo]

It occurred to me that most of ScubaBoard's readers probably don't know what a pure Oxygen rebreather is. Here is a diagram:

By Mark.murphy - Own work, CC BY-SA 3.0, File:Oxygen rebreather.PNG - Wikimedia Commons​

Note that use of pure Oxygen at depth is limited due to Oxygen toxicity. The advantage for combat swimmers is that virtually no telltale bubbles are emitted in addition to avoiding decompression limits and duration can be hours long.

 

[Angelo Farina]

This website has some nice piece of information:
Oxygen Rebreathers Italy

were using a different suit:
Italian Pirelli Diving Suit

A number of significant inventions went out from those pioneer frogmen, and Luigi Ferraro was definitely the most prolific inventor. Apart the Rondine fins, he was also the inventor of the Cressi Pinocchio mask, and of consequence of the modern equalization techniques (Marcante-Odaglia, for example, which was the Italian adaptation of the Frenzel technique, but usable with the mouthz open, as required when using an ARO rebreather).
And here Ferraro's "Technisub new ARO" rebreather, a milestone in the rebreather technology, dating around 1978:

In 1979 my diving club (Parmasub) was the proud owner of one of these expensive machines, and I had the privilege to test it in the sea (at Levanzo, near La Spezia). Actually I met Luigi Ferraro exactly in that period, when we went to Genoa at the Technisub factory (which was inside the Genoa's fair buildings, in the port) for purchasing this unit, and he carefully explained us the tricks for using it properly.
Luigi Ferraro was an excellent instructor, and the pioneer of recreational scuba diving courses. He started keeping them regularly in his diving school since 1948: Early Experiences | Luigi Ferraro
So these courses, all done using the ARO, are considered the first regular scuba diving school in the world.