The First Frogmen
The first well-known frogmen were the navy diver members of World War II Italian commando frogmen, now ComSubIn, being part of Decima Flottiglia MAS, nicknamed "Uomini Rana", Italian for "frog men", because of an underwater swimming frog kick style, similar to that of frogs. Originally these divers were called "Uomini Gamma" because they were members of the top secret special unit called "Gruppo Gamma", which originated from the kind of Pirelli rubber skin-suit nicknamed muta gamma used by these divers, but Uomini Rana was afterwards commonly used. This special corps used an early scuba set which did not make bubbles, called A.R.O (from Auto Respiratore ad Ossigeno), an evolution of the Dräger oxygen self-contained breathing apparatus designed for the mining industry and of the Davis Submerged Escape Apparatus made by Siebe, Gorman & Co and by Bergomi, designed for escaping from sunken submarines. This was used from about 1920 for spearfishing by Italian sport divers, modified and adapted by the Italian navy engineers for safe underwater use and build by Pirelli and SALVAS from about 1933, and so became a precursor of the modern rebreather.
For this new way of underwater diving, the Italian frogmen trained in La Spezia, Liguria, using the local Genoese newly diffused spearfishing free diving equipment (diving mask, snorkel, swimfins, wetsuit), the first specially made diving watch (the luminescent Panerai), and the new scuba unit. This was a revolutionary alternative way and the start of the transition from the usual heavy underwater diving of the hard hat divers (the only method used from the 18th century) to self-contained divers, free of being tethered by an air line and rope connection.
In 1933 Italian companies were already producing underwater oxygen rebreathers, but the first scuba diving set is generally recognised inside the USA as being invented in 1939 by Christian Lambertsen, who dubbed it the Lambertsen Amphibious Respirator Unit (LARU).
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