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by Admiral (ret) Attilio Duilio Ranieri

The submarine DIASPRO belonged to the series “PERLA” of the coastal submarines of the class “600”. The class “600”, unanimously recognized as one of the best Italian submarines of the time, was divided into five series, all slightly different:

Series ARGONAUTA, 7 units
Series SIRENA, 12 units
Series PERLA, 10 units
Series ADUA, 17 units, plus 3 for the Brazilian Navy
Series PLATINO, 13 units

For a total of 59 boats for Italy and 3 for Brazil.

The series “PERLA” was built between 1935 and 1936, part by the CRDA shipyard of Monfalcone, Gorizia (6 units), and part by the Shipyard OTO of Muggiano, La Spezia (4 units). The DIASPRO was built in Molfalcone: laud down on September 29th, 1935. It was launched on July 5th, 1936 and delivered to the Navy on August 22nd of the same year.

Operational Life

The operational life of the DIASPRO began early on. Under the command of Lieutenant Commander Giuseppe Mellina, the boat participated in the Spanish Civil War (1936-1939). The first patrol took place in 1937, north of Cape Bon (Tunisia), with an unsuccessful attack against two merchant ships. A second attack took place on September 1st in the waters off Benicarlò, north of Valencia, in which the British tanker WOODFORD of 6,987 t. was sunk. After the initial attack, and having avoided the first two torpedoes, the ship attempted to ram the submarine.

Upon Italy’s entry into the war (June 10th, 1940), the submarine was assigned to the 72nd Squadron of the 7th submarine group based in Cagliari, Sardinia. The war fought by the DIASPRO was long and hard, took place solely in the Mediterranean, and was intense: 53 operational patrols, of which 32 were offensive. It amounted to long and nerve-raking patrols, but lacked significant results. After all, in the Mediterranean, differently from the Atlantic, the enemy’s merchant traffic was limited and always heavily escorted. Nevertheless, the DIASPO was able to complete several attacks, but without tangible results (or at least this is what surfaced from post-war British documentation, but many times the weapons were heard to explode).

In the first two years of the war, the activity of the DIASPRO was almost exclusively restricted to the Channel of Sardinia. On September 1st, 1940 it was the object of a very harsh hunt by British aero naval units, and especially an airplane from which it defended itself with the machine guns, later being able to escape without damage.

With command transferred to Lieutenant Antonio Dotta, on July 22nd, 1941 while on patrol off Bougie (Algeria), the DIASPRO found itself in the middle of a large naval formation. It launched four torpedoes against an aircraft carrier, but failed to hit it, even if one of the weapons was heard to detonate. It then launched two torpedoes against one of the escort units, the destroyer H.M.S. NESTOR, missing it by “a hair”, as the British, who spotted the wave of the torpedoes, would later report.

From the 1st of April to September 10th, 1942 the boat was assigned to the submarine school of Pula where it completed 32 training missions with submarine cadets.

Returned to base, in November 1942 it again began operational activity. On the 8th, while submerged off Biserta (Tunisia), it had a small accident, fortunately not too serious: it collided with the submarine ALAGI. While the latter received damages which forced it to return to base, the DIASPRO was able to continue on with the patrol. On the 12th, it entered the Bay of Bougie where it attacked a large motor-ship, but the torpedoes failed to hit the target.

With the command of the boat transferred to Lieutenant Alberto Donato, on the night of July 13th, 1943 the DIASPO attacked a convoy in the waters off Cap de Fer (Algeria), but this time also the two torpedoes appeared to have failed to hit the target, despite the fact that after 2 minutes and 22 seconds, the time proscribed, two explosions were heard.

We insist on saying “it appeared” because there is a well-grounded suspicion that, in some cases, the British failed to report damages, even when these were quite possible. It could then be that the explosions heard were actual hits, but that they did not cause the loss of the ship. The fact that these events are not reported by the British documentation is not a guarantee of truthfulness, since the documents prepared at the time were useful to the propaganda and not to ascertain events. Even today, in the archives at the present time open to the public and accessible to everyone, there is a British resistance to admit (especially in the area of espionage) to facts already proven by other means. But let us return to the DIASPRO.

The last meaningful patrol before the armistice of September 8th, 1943 took place on August 18th, in the waters off Stromboli, when the boat launched two aft torpedoes against two destroyers, but without hitting them. The following day, while returning to Naples, the DIASPRO sighted two more destroyers, which were attacked with four torpedoes and, after the required time, two explosions were clearly heard. When, one hour later, the submarine surfaced, one of the two destroyers was still in the water and clearly damaged, but the boat had run out of torpedoes and could not but move on to Naples.

September 8th caught the DIASPRO at sea. Based on the clauses of the armistice, it should have sailed to Bona (Algeria), but due to technical problems it instead sailed to Cagliari. Up to that moment, the submarine had completed 53 patrols, with 806 days at sea for a total of 22,345 miles on the surface and 3,057 submerged.

Having completed the necessary repairs in Cagliari, in March 1944 the DIASPRO was transferred to Brindisi where it provided training support for the ships based in Brindisi and Taranto until April 1945. During this period, it also completed a special operation landing commandos in Zante and Cephalonia. In May 1945, it went to Malta to provide for anti-submarine training for allied ships.

Following the surrender of Japan in World War II, the DIASPRO returned to Taranto where it was removed from service. During the co-belligerence period, it completed 59 missions, 48 of which were for training, for a total of 4,030 miles.

On February 1st, 1948 the DIASPRO was definitely removed from service and, soon after, as prescribed by the armistice the blowtorch began the sad task of demolishing it. During its entire operational life, the DIASPRO had only one casualty: Sergeant Gaetano Loffredo.

Translated from Italian by Cristiano D'Adamo

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