March 1943
| 20 | March | U-boats appeared on the verge of victory in the Battle of the Atlantic. |
Italian submarine patrols in the Mediterranean during March 1943
| Aradam (…5 March) | Ascianghi (…5 March) | Beilul (…12 March) |
| Brin (2-21 March) | Dandolo (2-5 March) | Mocenigo (2-20 March) |
| Topazio (2-17 March) | Corridoni (12-14 March) Pt.1 | Sirena (13-15 March) |
| Corridoni (16-18 March) Pt.2 | Gorgo (18 March) | Nichelio (18 March) |
| Bragadino (22-25 March) Pt.1 | Bragadino (25-28 March) Pt.2 | Corridoni (29 March) Pt.1 |
| Wolframio (30 March…) | Ambra (31 March…) |
On the morning of 1 March, Argento (T.V. Renato Frascolla) sailed from Cagliari for La Maddalena. She was rounding Cavoli Island when she was sighted by the Dutch submarine Dolfijn (Lt Cdr H M.L.F.E. van Oostrom Soede), who had sunk Malachite three weeks earlier. Argento was luckier this time as she managed to avoid the salvo of four torpedoes directed at her. Following this attack, the Dutch submarine was hunted unsuccessfully by the patrol boats Idria and Bella Italia.
In the first hours of 2 March, Ascianghi (T.V. Rino Erler), patrolling northeast of Buerat (Libya), fired a salvo of three torpedoes at a Jervis-class destroyer in a large enemy formation. Erler claimed she was sunk, but British documents did not confirm this.
During the afternoon of 2 March, the submarines Brin (T.V. Luigi Andreotti), Dandolo (T.V. Giacomo Scano), and Mocenigo (T.V. Alberto Longhi) sailed from Cagliari to operate off the African coast.
On 7 March, Brin, patrolling off Cape Carbon, reported being targeted by many bombs and depth charges but was undamaged.
Luck was with Corridoni (T.V. Armando Rosso) on the 9th. She had sailed from Augusta for Trapani to pick up supplies for another transport mission when, at 0200 hours, she passed some 500 yards ahead of HMS United (Lt. J.C.Y. Roxburgh, DSC, RN). The British submarine had sent a folbot party for a beach reconnaissance (COPP III) of Gela and they had not yet returned. According to her instructions, she could not attack the enemy and was robbed of an easy success.
Two days later, near Cape Bougaroni, Mocenigo sighted a westbound Dido-class cruiser and, on 14 March, two cruisers of the same class and two Jervis-class destroyers. In both instances, she was too far to carry out an attack. Finally, she fired a full salvo at a freighter before dawn on 17 March but without success.
Loss of Delfino
In the afternoon on 23 March, while being transferred from Taranto to Augusta, Delfino (T.V. Mario Violante) collided with the pilot vessel Limbara 6.5 miles from San Vito Light and sank rapidly. Violante and twenty-two of his crew survived; twenty-eight went down with her. The submarine earned post-war notoriety for sinking the Hellenic light cruiser Helle in August 1940.
At 2320 hours on 23 March, two swimmers were reportedly seen by a breakwater patrol at Oran. They were also reported by the aircraft carrier HMS Formidable berthed alongside. They were shot at, and one was believed to have been hit. Their bodies were not found, and this was most likely a false alarm. After midnight, the destroyer HMS Tartar obtained an H/F D/F bearing on an Italian transmission in position 36°18’ N, 00°25’ W, reinforcing the belief that an attack was underway.
Before midnight on 29 March, Corridoni (T.V. Armando Rosso) was carrying supplies to Lampedusa when, east of Syracuse, she sighted an unidentified submarine. The Italian submarine refrained from taking action as the nationality could not be ascertained. This was most probably HMS Unison returning to Malta.
During the winter of 1942-1943, Italian submarines curtailed their activities in the Mediterranean as they braced for an attack on the homeland. This was considered a logical step, given the uncertainty surrounding the war in North Africa.
On 31 March 1943, Maricosom issued the order of Operation ZETA It was addressed to the twenty-two submarines of 2 Grupsom and 7 Grupsom. They were:
Acciaio, Alagi, Aradam, Argento, Argo, Ascianghi, Axum, Brin, Bronzo, Dandolo, Diaspro, Giada, Gorgo, Mocenigo, Nereide, Nichelio, Platino, Sirena, Topazio, Turchese, Velella and Wolframio.
The order was to prepare for an enemy landing on the west and south coasts of Sardinia. It specified attacking enemy ships in the following order of preference: transports, aircraft carriers, battleships, and cruisers. Submarines, destroyers, and MTBs were not to be attacked.
Italian submarine patrols in the Atlantic during March 1943
| Cappellini (…) | Barbarigo (…) | Torelli (…) |
| Bagnolini (…) | Archimede (…) | Finzi (…) |
| Da Vinci (…) |
Barbarigo (C.C. Roberto Rigoli) was still on patrol off Brazil when, with three torpedoes, she sank the Brazilian Affonso Penna (3,540 GRT, built 1910) before midnight on 2 March. The submarine fired off one round before realising that the vessel had many passengers, and the firing was immediately checked. The vessel carried 242 people. Thirty-one crew and eighty-four passengers perished, the American Tennessee found some 119 survivors, and eight more reached the Brazilian coast in their lifeboat.
Two days later, at about the same time, Barbarigo dispatched the American Stag Hound (8,591 GRT, built 1942). The Argentine freighter Rio Colorado picked up all the eighty-four crew members and passengers. On 11 March, as she was returning to base, she met Torelli (C.C. Antonio De Giacomo) and ceded 26 tons of fuel.
On 14 March 1943, Da Vinci (T.V. Gianfranco Gazzana Priaroggia, promoted to Capitano di corvetta on 16 May 1943) was cruising the South Atlantic when she fired a salvo of three torpedoes at the liner Empress of Canada (21,517 GRT, built 1922). Two torpedoes hit the target, sending her to the bottom. She was transporting a number of British soldiers and 500 Italian prisoners of war. There were 392 victims (of these, 340 were passengers, mostly Italian prisoners of war, forty-four crew members, and eight gunners). The submarine picked up an Italian doctor. Several ships were directed to the location of the tragedy, HMS Boreas, Petunia, Crocus, and Corinthian. They picked up 1,519 survivors.
Bagnolini (T.V. Angelo Amendolia) was patrolling off Brazil when, on the morning of 15 March, she was seen by a Pan American Airways Clipper, which reported the submarine. In the afternoon, the Italian submarine was sighted by Catalina P-12 but managed to dive before an attack was carried out. But her troubles were not over. Before midnight, she was located by Catalina P-4 (#2471) of USN squadron VP-83 piloted by Lieutenant Commander B.J. Prueher, USN. The aircraft illuminated his target and dropped four depth charges on the diving submarine. As she had barely reached a depth of fifteen metres, she was shaken by two explosions that put her hydrophones out of service. On 11 August 1943, Prueher was killed with his whole crew as he piloted a Liberator of VB-107 Squadron in an attack on U-172, U-185, and U-604 as they rendezvoused in the Mid-Atlantic.
Torelli’s (C.C. Antonio De Giacomo) patrol was cut short on the evening of 16 March when she was attacked twice by enemy fighters. The first attack was carried out by a Dauntless (SBD) of VC-29 Squadron piloted by Ensign E.M. Koos from the escort carrier USS Santee (CVE-29). The aircraft delivered a bomb; it missed the submarine by thirty metres. Torelli replied with her machine guns; Koos was wounded, and his radio was put out of use, but he managed to bring his plane back on the aircraft carrier. The alarm was given, and more aircraft took off to hunt the submarine. This time the Italian was attacked by another Dauntless piloted by Ensign J. Oster and an Avenger piloted by Ensign W.R. Taylor. They were described as three Helldivers, and Torelli claimed to have shot down one of them; this was not true. The American aircraft dropped bombs, and though they missed the submarine, their strafing was murderous. Five men were hit, including De Giacomo. Two men would succumb to their wounds. S.T.V. Sergio Dechecchi took over command and brought the boat back to Bordeaux. On 25 March, he was offered the assistance of a medical officer from a German U-boat but declined as the three wounded were recovering.
On the evening of 18 March, Finzi (T.V. Mario Rossetto) fired three single torpedoes at the British Lulworth Hill (7,628 GRT, built 1940) on passage from Mauritius to Freetown; they all missed. The freighter kept the submarine at bay by opening fire with her stern gun. Her luck was short-lived, and in the early hours of the next day, she came across the redoubtable Da Vinci, who sent her to the bottom. The Italian submarine picked up a survivor, and he was transferred with the Italian doctor to the Finzi the following evening. They were the only surviving witnesses of the last days of this famous submarine. Da Vinci took ninety tons of fuel from Finzi as well as three 450mm torpedoes. She would later disappear with all hands. Forty-three men of Lulworth Hill perished. Two survivors in a raft had an ordeal of forty-nine days before they were picked up by the destroyer HMS Rapid.
on 19 March 1943 (USMM)
In the meantime, Finzi had been adding to her score, sinking the Greek Granicos (3,689 GRT, built 1916) on 28 March. She picked up a Portuguese man, the lone survivor of this ship; thirty men were killed. After midnight on 30 March, with a pair of torpedoes, Finzi missed the British Celtic Star (5,575 GRT, built 1918) on a voyage from Manchester and Greenock to Montevideo and Buenos Aires. Two additional torpedoes disposed of her. This time, the submarine picked up a Canadian survivor. Two were killed, and a search by HMS Fandango, Aimwell, and Wastwater found the remaining sixty-three survivors.