Italian Frogmen (combat swimmers)

[Akimbo]

And here Ferraro's "Technisub new ARO" rebreather, a milestone in the rebreather technology, dating around 1978:

Is this a front-mount only or can it also be worn back-mount? Hard to tell from the image.

For other readers, combat swimmers tend to prefer wearing the rebreather in front so they can see what is going on and they have very little need to look down. They are usually swimming a compass course at 20' or 6M at night.

 

[Angelo Farina]

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

View attachment 664772
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.

This is the scheme of "loop" rebreathers (with two corrugated hoses). The original Italian military ARO units were "pendular" units, where the gas is expelled and inhaled back through a single hose. This way the filter is crossed twice, both when exhaling and when inhaling, but these units did require to employ a special ventilation technique, with very profound exhalations and inhalations and a long inspiratory pause (up to 20-30s). in case the diver was venting short, the filtering was ineffective and the CO2 did build up.

 

[Akimbo]

in case the diver was venting short, the filtering was ineffective and the CO2 did build up.

Are there any "single hose" rebreathers still on the market?

Here's my first rebreather story:

Related Story:
My very first direct experience around rebreathers was with a friend who build one. He had a PhD in chemistry and was normally a pretty meticulous guy. It was about 1964 and most of the parts were from war surplus pure O2 rebreathers. He was testing it in a swimming pool and forgot to purge the loop of air. After a few minutes be breathed the Oxygen down enough that he slowly blacked out, but the single breathing bag was still inflated enough that adding O2 was not triggered — which was manual as I recall. Nobody suspected it until he rolled on his back at the bottom of the pool and the mouthpiece floated out.

I was 13. Two of the adults dove in, recovered him, and started CPR. He came to and said "sh*t, I forgot to purge the bag". It made quite an impression.

Years later, I was on a team headed by a saturation-qualified US Navy Master Diver investigating an Oxygen fire at the UDT and SEAL (they were still separate at that point) training facility in San Diego (Coronado). We observed how they purged their pure O2 rigs as part of their predive prep. They blow a LOT of O2 threw the loop and closed the mouthpiece valve before disconnecting from the fill station. It was about 4x as much gas as I would have guessed would be required.

 

[Angelo Farina]

Is this a front-mount only or can it also be worn back-mount? Hard to tell from the image.

For other readers, combat swimmers tend to prefer wearing the rebreather in front so they can see what is going on and they have very little need to look down. They are usually swimming a compass course at 20' or 6M at night.

All Italian AROs has always been chest mounted.

the Technisub New ARO was not an exception.

But now we have the current unit actually employed by Italian Comsubin, the OMG (now SIEL) Caimano IV:

this is the first Italian ARO unit which can also be backmounted, as shown here:

 

[Angelo Farina]

Are there any "single hose" rebreathers still on the market?

The Naubos was in production until recently, and used in ARO courses here in Italy:
NAUTILUS Aro Naubos AR 88 - AR 90 - rebreather | BluTimeScubaHistory

 

[ginti]

Is this a front-mount only or can it also be worn back-mount? Hard to tell from the image.

For other readers, combat swimmers tend to prefer wearing the rebreather in front so they can see what is going on and they have very little need to look down. They are usually swimming a compass course at 20' or 6M at night.

@Akimbo as far as I understand you are a former US Navy diver right?

Have you seen during your training anything that can relate to Italian frogmen? I ask because apparently, the Decima was the model for modern frogmen units, and perhaps part of the knowledge was brought also to navy divers... just curious here

 

[Akimbo]

@Akimbo as far as I understand you are a former US Navy diver right?

Guilty.

Have you seen during your training anything that can relate to Italian frogmen?

No, not in my training. We didn't formally learn anything about working divers in other navies either, but the focus was always on what we needed to know to get the job done without killing ourselves.

US Navy divers (working divers) and SEALs (combat swimmers/special forces) don't attend the same dive schools so I really have no idea. I am guessing that they learn about the heritage of the UDT (US Underwater Demolition Teams) since many of their traditions date back to that beginning. AFAIK, the US didn't have any combat swimmers before World War II. The UDT's focus during the war was more on landing beach surveys and clearance than ship espionage.

From my reading, what became the UDT and later the SEALs was a collection of several groups that formed during the war. See SEAL History: Origins of Naval Special Warfare-WWII

Maybe @ND5342 knows more about it since he worked with SEALs?

 

[ginti]

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

By the way, this is probably one of the first (if not the absolute first) military frogman, and the guy I was referring to in the previous post:
Raffaele Rossetti - Wikipedia

Unfortunately, there is not much information about the equipment they used at that time (WWI); probably just standard diving dress and rebreathers.

On this (Italian) page, you can find info about the human torpedo they used:
Torpedine semovente Rossetti - Wikipedia

On this other (Italian) page, there is some info about the first rebreathers before WWII:
https://archive.is/20120710031009/h...ni/storia/frameset.htm#selection-849.0-849.13

I guess you guys need a bit of google translator if you try to translate and something is unclear, feel free to ask me for help.

Anyway, let's go back to the topic. Some rebreathers were in the Italian market in the 30s and were artisanal machines used by sport spearfishing divers.

I couldn't find any information about the suits antecedent the Belloni model; I guess they were standard diving dress; if my guess is correct, it means that rubber (and, therefore, latex) was one of the most significant innovations by the Decima. I am not sure whether the Belloni suit was in rubber or if the first rubber suit was the Pirelli.

 

[Angelo Farina]

By the way, this is probably one of the first (if not the absolute first) military frogman, and the guy I was referring to in the previous post:
Raffaele Rossetti - Wikipedia

Unfortunately, there is not much information about the equipment they used at that time (WWI); probably just standard diving dress and rebreathers.

On this (Italian) page, you can find info about the human torpedo they used:
Torpedine semovente Rossetti - Wikipedia

On this other (Italian) page, there is some info about the first rebreather before WWII:
https://archive.is/20120710031009/h...ni/storia/frameset.htm#selection-849.0-849.13

I guess you guys need a bit of google translator if you try to translate and something is unclear, feel free to ask me for help.

Anyway, let's go back to the topic. Some rebreathers were in the Italian market in the 30s and were artisanal machines used by sport spearfishing divers.

I couldn't find any information about the suits antecedent the Belloni model; I guess they were standard diving dress; if my guess is correct, it means that rubber (and, therefore, latex) was one of the most significant innovations by the Decima. I am not sure whether the Belloni suit was in rubber or if the first rubber suit was the Pirelli.

here a document with another history of the ARO rebreather, bilingual Italian-English: https://www.anaim.it/wordpress/wp-content/uploads/HDSN25.pdf

 

[DiznNC]

This is a very timely topic for me. I am very interested in getting one of these Italian O2 CCR rigs. They have gone through many companies, but I believe the current one is Sanosub, making the AROC96 O2 rebreather. Obviously the model name harks back to the original rigs, which it strongly resembles, with a few updates, such as the dual hoses and an O2 gauge. I am a retired Marine and old OC diver that has always wanted to try an O2 CCR rig. Big fan of all the military frogmen out there, including Decima-Mas and their grandsons with Comsubin.

For any of you guys that have dived/are diving these rigs, any info you could provide would be highly appreciated. I have contacted Sanosub and am talking to them about purchasing one of their rigs, and am also looking for any training agency that could train me up in their use, here in the states.

But not to jack the thread, always been a big fan of Decima-Mas and their Maiale attacks on shipping during the WWII. These guys were truly the first combat frogmen that used some kind of breathing apparatus, not to mention the first "SDV". I admire them even more because they are still very secretive in their current endeavors, unlike some others. That must have been fantastic to actually meet one of these guys.

As far as our guys, in the UDT and later Seal teams, I reference the "UDT Handbook" (amazon) for the brief history of the rigs used. As far as I can tell, the Pirelli 701 and 901 rigs were used in the immediate post-war years, then the German "Lt. Lund II", then the US Emerson-Lambert designs (both the "Mk V" then "MK VI" semi-closed, mixed gas rebreather, and the "Emerson O2 rig", MK-designator unknown, which was an O2 CCR). These were replaced with the LAR V and now the MK 25. You could say the "Mk VI" was replaced with the "MK-15", as far as a semi-closed, mix-gas rigs goes.

Siel/OMG now makes two rigs which essentially do the same things for the Italians. Both an O2 CCR, and a mixed gas SCR. Unfortunately their C96 Pro is no longer sold to the public, so that is why I'm interested in the Sonosub model. Some may think this is stupid, for wanting a pure O2 CCR, and being limited to 6m, but for me this is a huge piece of history that I would love to have a chance to emulate. Strictly for recreation, of course.