The SLC (Slow Moving Torpedo) was the best known assault weapon of the Regia Marina during World War II.

The Miale is a torpedo on which two guys ride like a motorcycle. They were also called 'Chariot' and gave the Royal Navy fits both at Alexandria and Gibraltar.

This new torpedo, nicknamed 'maiale' (pig or hog), was equipped with, among other things, diving planes, ballast tanks and compressed air for the release of ballast, thus allowing for full underwater navigation just like a submarine.

The models built from the original 1936 prototype used an electric motor with power increased from 1 hp up to 1.6hp. The batteries were increased to a total of l50 amps. Specific efforts were made in bettering the equipment - a magnetic compass was preferred to a gyroscopic one due to difficulties encountered in miniaturizing such a complex device. The magnetic compass was improved, rendering it less susceptible to magnetic interference.

The breathing apparatus used by the operators was also notably improved. After having noted the unreliability of the Davis hoods used on submarines, studies were begun on specific apparatuses capable of providing longer autonomy and complete safety.

To avoid bubbles rising to the surface, which would have revealed the presence of a diver, the Regia Marina employed special devices specifically built by Pirelli, which utilized a sealed system. These breathing apparatuses were not fueled by compressed air, but instead by pure oxygen. The use of oxygen eliminated the presence of bubbles since it did not produce exhaust gasses.

During breathing, the expended oxygen is turned into carbon monoxide which is then purified by a lime-based filter (sodium carbonate and lime). A closed system allows the apparatus to function until the lime is saturated and cannot absorb any more carbon monoxide. The ARO, as it was designated by the Navy, eliminated the risk of the bends typical of the compressed air apparatus (designated as ARA) and the fastidious decompression stages required during ascent.

Nowadays we know that breathing pure oxygen stresses the central nervous system and can cause epileptic episodes, but no one remembers any such occurrences during the training conducted by the Italian divers. Therefore, it is believed that the oxygen in use was not 100% pure. As a matter of fact, it is recorded that divers experienced 'breathlessness' typical of carbon monoxide intoxication.

Regardless, divers experienced some maladies caused by oxygen breathing at certain depths. The maximum submerged depth of an ARO apparatus should not exceed 15 meters (about 48 feet) but it was known that depths of up to 30 meters (about 100 feet) were often reached.

Many thanks, VINCENT. We urge other Members to do this kind of research and writing for our KTB Magazine. Now that you have seen a photo of the 'Maiale' or 'Charlot' ' how many submariners - from the war years or after - would want to go, into combat straddling a torpedo like a motorcycle?

Maybe that's one reason why I joined the Air Force!