The importance of submarines was always known to the Regia Marina. Italy had one of the largest submarine force in the world. In the beginning of the war, Italy had 117 submarines of which only 7 could be considered out of date. Italian submarines were located throughout the war and patrolled the Mediterranean, Atlantic, Red Sea, Black Sea and even the Indian Ocean. Their success rate was diminished by a number of factors, but was still comparable to the German U-Boats when considering Number of Attacks/Ships Sunk.
One was the fact that most of the submarines were technologically inferior to the Germans. The Italian smg’s did not possess an adequate snorkel for diesel operations underwater and their profile was so big that made them easily detected in the clear Mediterranean waters. Smg’s did not operate well in the “wolf pack” style so a large part of their operations were conducted independently (especially in the Atlantic and South Atlantic).
The Regia Marina was also in fault because of their strict patrol orders of its Navy. The layout of the patrol for all navy vessels was laid out prior to the ships leaving port. To deviate from the “set” patrol was an extremely difficult task to accomplish and hampered any advantage the submarines may have gained by choosing its own course.
One aspect of the Italian submarine that was commendable was their advanced Torpedo design. Prof. Carlos Calosi was the inventor of the magnetically activated torpedo, which could sink a ship merely by passing underneath its hull. That may be one of the reasons why Italian submarines had such a good attack/kill ratio.
On a side note, during the Italian Armistice, Calosi, by order of the Italian Navy Experimental Weapons Division, gave the Allies a countermeasure which disrupted the magnetic field of the torpedo, which was eventually used by the thousands in German U-Boats by the end of ’43. This countermeasure was placed on Merchant Ships which rendered the Torpedoes virtually harmless.
Italian submarines suffered a heavy casualty rate as Allied ASW grew more advanced and by September 8, 1943, Italy had only 54 submarines left out of a total 184 submarines built. At the end of the armistice, Italy was able to keep only 2 submarines, the Smg Giada and Smg Vortice.
|Total Active Boats||172|
|Merchant Ships Sunk||129|
|Merchant Tonnage Sunk||668,311|
|Total Torpedo Launches||427|
|Subs Lost in Mediterranean||88|
|Subs Lost Elsewhere||40|
|Total Days at Sea||24,000|
Additional Italian submarine attack statistics in xls format.