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Slow Moving Torpedo
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Narrative |
| The SLC (Slow Moving Torpedo) was the best known assault weapon of the
Regia Marina during World War II. This new torpedo, nicknamed "maiale" (pig or
hog, depending on the author), was equipped, amongst other things, with diving planes,
ballast tanks, and compressed air for the release of ballast, thus allowing for full
underwater navigation, just like a submarine. |
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| The models built after the original 1936 prototype employed an electric
motor with power increased from 1 to 1.6 HP. Batteries were increased to a total of 150
Amp. Specific efforts were made in bettering equipment; a magnetic compass, for instance,
was preferred to a gyroscopic one, due to the difficulties encountered in miniaturizing
such a complex device. The magnetic compass was improved, rendering it less susceptible to
magnetic interference. |
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| 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
began 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
used pure oxygen. The use of oxygen eliminated the presence of bubbles since it did not
produce exhaust gases. 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 for the apparatus to function until the lime is saturated and cannot
any longer absorb the 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. |
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| Nowadays we know that breathing pure oxygen stresses the central nervous
system and can cause epileptic episodes, but no one recollects 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 have not exceeded -15 meters (- 45 feet), but
it was known that depths of up to -30 meters (-90feet) were often reached. Adapted
from: 'Imagini di Storia - Decima MAS: I mezzi d'assalto della Marina Italiana - N7
gennaio 1995 |
| Shipyard | Officine San Bartolomeo La Spezía |
| Year built | from 1935 |
| Length | 6,70 meters |
| Width | 533 mm |
| Max Depth | -15 ~ -30 meters |
| Engine | Electric motor 1.6 HP |
| Speed | Max 4,5 knots - operational 2,3 knots |
| Range | 4
miles at maximum speed 75 miles at operational speed |
| Weapons |
Mark I: a 220 kg
explosive charge Later versions a 250 kg explosive charge Final version: a 300 kg explosive charge |
| Crew | 2 |
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| © 1996-2007 REGIAMARINA (TM) - Terms and Conditions | ||
