The Marconi class was a class of six submarines built for the Royal Italian Navy (). The submarines were all launched between 1939 and 1940, and all but one, , were lost in the Atlantic during the Second World War.

Class members Guglielmo Marconi Guglielmo Marconi (pennant number MN) was launched 27 July 1939Kafka & Pepperburg p.791 and completed on 2 February 1940. On its first wartime patrol in the Mediterranean Sea, Marconi torpedoed the Royal Navy destroyer on 8 July 1940. Marconi sailed on 6 September 1940 and passed the Strait of Gibraltar on 11 September for an Atlantic patrol to Bordeaux on 29 September. En route Marconi sank the neutral Spanish fishing boat Almirante Jose de Carranza. Marconi sank one ship on its first BETASOM patrol from Bordeaux. After an unsuccessful patrol, Marconi sank three ships on its third BETASOM patrol and damaged a Yugoslavian freighter on the following patrol which was later sunk by . Marconi was lost to unknown causes sometime after 28 October 1941 on its fifth BETASOM patrol.

+ Ships sunk by Marconi Ship Flag Patrol Date Tonnage () Notes 1st 8 July 1940 Destroyer; 2 killed Vingaland 3rd 9 November 1940 2,734 gross register tons (GRT) Freighter from Convoy HX 84 Cairndale 5th 30 May 1941 8,129 Tanker; 4 killed Baron Lovat 5th 6 June 1941 3,395 Freighter from Convoy OG 63 Taberg 5th 6 June 1941 1,392 Freighter from Convoy OG 63, 6 survivors from a crew of 22 Total: 17,055

Leonardo da Vinci (pennant number LV) was launched 16 September 1939. da Vinci sailed on 22 September 1940 and passed the Strait of Gibraltar on 27 September for an Atlantic patrol to Bordeaux on 31 October. After unsuccessful patrols from 21 December to 20 January 1941 and from 4 April to 4 May, da Vinci sank one ship on its third BETASOM patrol. After another unsuccessful patrol from 15 August to 24 September, da Vinci sank two ships during Operation Neuland and four ships on the following patrol. After being modified to carry a midget submarine, da Vinci sailed without the midget submarine and sank four ships. Sailing again without the midget submarine, da Vinci sank six ships on its last patrol. While attempting to return to Bordeaux, da Vinci was sunk on 23 May 1943 by the escorts of convoy KMF 15. There were no survivors. Leonardo da Vinci was the top scoring non-German submarine of the entire war.Clay Blair, Hitler's U-boat War: The Hunters, 1939-1942, p.740The US Navy's most successful submarine, , sank 116,454 GRT, while , the Royal Navy's most successful submarine, sank 93,031 GRT of shipping.

+ Ships sunk by da Vinci Ship Flag Patrol Date Tonnage () Notes Auris 4th 28 June 1941 8,030 Tanker; 27 survivors from a crew of 59 Cadebello 6th 25 February 1942 3,557 Freighter; no survivors Everasma 6th 28 February 1942 3,644 Freighter from Convoy TAW 12 torpedoed at ; 15 survivors Reine Marie Stewart 7th 2 June 1942 1,087 Schooner Chile 7th 7 June 1942 6,956 Freighter; 39 survivors from a crew of 44 Alioth 7th 10 June 1942 5,483 Freighter; 8 survivors from a crew of 36 Clan Macquarrie 7th 13 June 1942 6,471 Collier; 1 killed from a crew of 90 Empire Zeal 8th 2 November 1942 7,009 Freighter Andreas 8th 5 November 1942 6,566 Freighter Marcus Whitman 8th 10 November 1942 7,176 Liberty ship; no casualties Veerhaven 8th 11 November 1942 5,291 Freighter; no casualties 9th 14 March 1943 21,517 Troopship; 392 killed from 1,800 aboard 9th 18 March 1943 7,628 Freighter Sembilan 9th 17 April 1943 6,566 Freighter Manar 9th 18 April 1943 8,007 Freighter John Drayton 9th 21 April 1943 7,177 Liberty ship Doryessa 9th 25 April 1943 8,078 Tanker; 11 survivors from a crew of 54 Total: 120,243

Michele Bianchi (pennant number BH) was launched 3 December 1939. Its first war patrol was in the Mediterranean Sea from 15 August to 3 September 1940. Bianchi sailed on 27 October 1940 and reached the Strait of Gibraltar on 3 November. The attempted transit to the Atlantic was detected by Royal Navy forces; and Bianchi took refuge in the neutral port of Tangier. Bianchi sailed from Tangier on 12 November and reached Bordeaux on 18 December 1940. Bianchi sank three ships on its first BETASOM patrol from Bordeaux; but the next patrol from 30 April to 30 May 1941 was unsuccessful. After sailing from Bordeaux on 4 July 1941, Bianchi was sunk with all hands by on 5 July.

+ Ships sunk by Bianchi Ship Flag Patrol Date Tonnage () Notes Belcrest 4th 14 February 1941 4,517 Freighter from Convoy SC 21; no survivors Huntingdon 4th 24 February 1941 10,946 Credit for sinking shared with ; no casualties Baltistan 4th 27 February 1941 6,803 Freighter; 18 survivors from a crew of 69 Total: 22,266

Luigi Torelli Torelli (pennant number TI) was launched 6 January 1940. After one short war patrol in the Mediterranean, Torelli sailed on 31 August 1940 and passed the Strait of Gibraltar on 8 September for an Atlantic patrol to Bordeaux on 5 October. Torelli sank four ships on its first BETASOM patrol; and, after an unsuccessful second patrol, sank one ship on a third patrol. After another unsuccessful patrol, Torelli assisted the three s on a rescue mission of 254 sailors from the sunken in December 1941.

Torelli sank two ships during Operation Neuland. Torelli again sailed from Bordeaux on 2 June 1942, but was twice damaged by aircraft and sought refuge in the neutral Spanish ports of Avilés and Santander, Cantabria before returning to Bordeaux on 15 July. After an extensive refit, Torelli was again damaged at sea by aircraft on 16 March 1943 and returned to Bordeaux on 3 April. Torelli was then selected for conversion to a "transport submarine" in order to exchange rare or irreplaceable trade goods with Japan. Cargo capacity of 160 tons reduced reserve buoyancy from 20–25% to 3.5–6%; and armament was reduced to defensive machine guns. Torelli sailed as a transport submarine on 18 June 1943 and reached Penang on 27 August 1943.Brice pp. 129–133

UIT-25 Torelli was commissioned into the German Kriegsmarine as UIT-25 when Italy capitulated to the Allies in September 1943.

I-504 UIT-25 was taken over by the Imperial Japanese Navy and became I-504 when Germany surrendered in May 1945. I-504 shot down a B-25 Mitchell bomber while under Japanese flag near the very end of the war in the Pacific,Willmott p.276 allegedly the last success of a Japanese naval vessel in that conflict. It was found at Kobe when Japan surrendered and scuttled by the United States Navy in Kii Suido.Taylor pp.118-119, 140, 163

+ Ships sunk by Torelli Ship Flag Patrol Date Tonnage () Notes Nemea 3rd 15 January 1941 5,198 Freighter; 14 survivors from a crew of 31 Brask 3rd 15 January 1941 4,079 Freighter; 20 survivors from a crew of 32 Nicolas Filinis 3rd 16 January 1941 3,111 Freighter; 26 survivors from a crew of 29 Urla 3rd 28 January 1941 5,198 Freighter; no casualties Ida Knudsen 5th 21 July 1941 8,913 Tanker; 5 killed Scottish Star 8th 19 February 1942 7,224 Freighter; 4 killed from a crew of 73 Esso Copenhagen 8th 25 February 1942 9,245 Tanker; 1 killed from a crew of 39 Total: 42,968

Alessandro Malaspina (pennant number MP) was launched 18 February 1940 and completed on 20 June 1940. Its first patrol was through the Strait of Gibraltar on 3 August for an Atlantic patrol. Malaspina sank one ship before reaching Bordeaux on 4 September. Admiral Karl Dönitz visited Malaspina on 30 September to welcome Regia Marina sailors to the German base. The first BETASOM patrols from 9 October to 9 November 1940, from 5 January to 28 February 1941 were unsuccessful; but during a third patrol Malaspina damaged the British liner Lycaon on 3 May 1941. Malaspina then sank two ships on the next patrol. Malaspina sailed from Bordeaux on 7 September 1941; and is believed to have been sunk on 10 September by No. 10 Squadron RAAF Short Sunderland "U".

+ Ships sunk by Malaspina Ship Flag Patrol Date Tonnage () Notes British Fame 1st 12 August 1940 8,406 Tanker from Convoy OB 193; 3 killed from crew of 49 Lycaon 3rd 3 May 1941 Passenger Liner. Damaged Nikiklis 4th 14 July 1941 3,576 Freighter; 11 killed from crew of 28 Guelma 4th 17 July 1941 4,402 Freighter; no casualties Total: 16,384

Maggiore Baracca (pennant number BC) was launched 21 April 1940 and completed on 10 July 1940. Its first patrol was through the Strait of Gibraltar on 7 September for an Atlantic patrol. Baracca sank one ship before reaching Bordeaux on 6 October. Baracca sank one ship on its first BETASOM patrol from Bordeaux, but last four patrols were unsuccessful. On the final patrol, Baracca was sunk by on 7 September 1941. Thirty-two members of the submarine crew survived the sinking.

+ Ships sunk by Baracca Ship Flag Patrol Date Tonnage () Notes Aghios Nicolaus 1st 1 October 1940 3,687 Freighter Lilian Moller 2nd 18 November 1940 4,866 Freighter; no survivors Total: 8,553

See also Italian submarines of World War II

Notes

References Marconi class at regiamarina.net Bagnasco, Erminio (1977) Submarines of World War Two London, Cassell & Co, Brice, Martin (1981) Axis Blockade Runners of World War II Annapolis, MD, Naval Institute Press, Kafka, Roger & Pepperburg, Roy L. (1946) Warships of the World Cornell Maritime Press Taylor, J.C. (1966) German Warships of World War II Doubleday & Company Willmott, H.P. (2009) The Last Century of Sea Power: From Port Arthur to Chanak, 1894-1922 Indiana University Press,

External links Guglielmo Marconi (1939) Marina Militare website