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Bordeaux Sommergibili
Bordeaux, France
BETASOM is located in France
Coordinates44°52′03″N 0°33′34″W / 44.867534°N 0.559341°W / 44.867534; -0.559341
TypeSubmarine base
Site information
Controlled by Kingdom of Italy
Site history
In useAugust 1940–September 1943
Battles/warsBattle of the Atlantic
Garrison information
Angelo Parona (August 1940-September 1941)
Romolo Polacchini (September 1941-December 1942)
Enzo Grossi (December 1942-September 1943)
Occupants Regia Marina

BETASOM (an Italian language acronym of Bordeaux Sommergibile or Sommergibili)[1] was a submarine base established at Bordeaux, France by the Italian Regia Marina Italiana during World War II. From this base, Italian submarines participated in the Battle of the Atlantic from 1940 to 1943 as part of the Axis anti-shipping campaign against the Allies.


Axis naval co-operation started after the signing of the Pact of Steel in June 1939 with meetings in Friedrichshafen, Germany, and an agreement to exchange technical information. After the Italian entry into the war and the Fall of France, the Italian Royal Navy established a submarine base at Bordeaux, which was within the German occupation zone; the Italians were allocated a sector of the Atlantic south of Lisbon to patrol. The base was opened in August 1940, and in 1941 the captured French passenger ship De Grasse was used as a depot ship before being returned to the Vichy French Government in June 1942. Admiral Angelo Parona commanded the submarines at BETASOM under the operational control of Konteradmiral (Rear Admiral) Karl Dönitz. Dönitz was the "Commander of the Submarines" (Befehlshaber der U-Boote) for the German Kriegsmarine. About 1,600 men were based at BETASOM.[2]

The base could house up to thirty submarines, and it had dry docks and two basins connected by locks. Shore barracks accommodated a security guard of 250 men of the San Marco Regiment.

A second base was established at La Pallice in La Rochelle, France; this second base allowed submerged training which was not possible at Bordeaux.

Operational detail[edit]

From June 1940, three Italian submarines patrolled off the Canary Islands and Madeira, followed by three more off the Azores; when these patrols were completed, the six boats returned to their new base at Bordeaux. Their initial patrol area was the Northwestern Approaches and at the start they out-numbered their German allies' submarines. Dönitz was pragmatic about the Italians, seeing them as inexperienced, but useful for reconnaissance and likely to gain expertise.[3]

Initially, the results were disappointing; the Italian submarines sighted convoys but lost contact and failed to make effective reports. Fearing that German operations would be prejudiced, Dönitz reassigned the Italians to the southern area where they could act independently. In this way, about thirty Italian boats achieved some success, though without much impact on the most critical areas of the campaign.[3][4]

Dönitz considered the Italians as displaying "great dash and daring in battle, often exceeding that of Germans", but less toughness, endurance and tenacity;[5] when the British tanker British Fame was attacked by the Malaspina, the officer of the watch and lookouts were on the bridge and the captain, according to the survivors of the tanker, "was dozing in a deckchair below" (Italian sources, including the memoirs of Malaspina's commander, Mario Leoni, deny these claims). It took five torpedoes to sink the tanker (but this was a rather common problem with tankers, that owing to their structure were often able to survive multiple torpedo hits if they did not catch fire) and, at one point, the tanker's gunfire forced the Malaspina to submerge; the Italians towed the lifeboats to safety, an act worthy of praise, but one against Dönitz's orders and leaving the submarine open to attack for 24 hours.[3]

While the BETASOM submarines did have some value, it is clear why they did not meet the expectations of Dönitz. By 30 November 1940, Italian submarines in the Atlantic each sank an average of 200 gross tons per day. By comparison, German U-boats each averaged 1,115 gross tons per day during the same time period. Italian submarines, however, had only been in the Atlantic for a few months at this time, and had not had yet the time to adapt to the new operational conditions, whereas the U-Boats had already been operating there for more than a year.

In an attempt to improve the performance of the Italian submarines, several measures were taken: taking cue from the Kriegsmarine, older Italian submarine commanders (some were 40 years old) were replaced with younger officers, who possessed more aggressiveness and stamina; a "submarine school" was created in Gotenhafen, where commanders, officers and bridge crews of the BETASOM submarines were trained according to the German model (the submarine Reginaldo Giuliani was assigned to this task, in cooperation with German naval units).[6]:471-481 Italian submarines also underwent improvement work, such as the reshaping of their excessively large turrets.

These measures significantly improved the performance of the remaining Italian submarines (about half of the BETASOM boats were recalled to the Mediterranean in 1941); the average tonnage sunk by BETASOM submarines rose from 3,844 Gross Register Tons (GRT) in 1940 to 27,335 GRT in 1942 (and, respectively, from 7,779 GRT to 68,337 GRT per actually operating submarine);[6]:692 the tonnage sunk for every lost submarine was 32,672 GRT in 1940 (opposed to 188,423 GRT for German submarines), 20,432 GRT in 1941 (70,871 GRT for Germans submarines), 136,674 GRT in 1942 (68,801 GRT for German submarines) and 13,498 GRT in 1943 (11,391 GRT for German submarines).[6]:692

Between February and March 1942, five BETASOM submarines (along with six German U-Boats) took part in Operation Neuland, sinking 15 of the 45 Allied merchant ships destroyed during this operation; the top scoring BETASOM aces, Gianfranco Gazzana-Priaroggia (90,601 GRT sunk) and Carlo Fecia di Cossato (96,553 GRT sunk), were among the few Italian recipients of the Knight's Cross of the Iron Cross. Gazzana-Priaroggia's boat, Leonardo da Vinci, held the distinction of being the top-scoring non-German submarine of World War II, with 17 ships sunk totalling 120,243 GRT.[7][8]

Italian naval historian Giorgio Giorgerini has put forward the view that, although Italian submarines did not perform as well as the U-boats, they did achieve a good success considering the deficiencies of their boats (among which were the lack of modern torpedo fire-control systems, and their slower speed both surfaced and submerged). Taking into consideration the period in which the BETASOM submarines operated and the numbers of submarines employed, comparing the respective tonnages sunk by U-boats compared to the Italian submarines and their respective losses (16 Italian submarines lost against 247 U-boats), it can be seen that the respective "exchange rates" (gross tonnage sunk divided by the number submarines lost) were respectively 40.591 t for the German units and 34.512 t for the Italian ones, meaning that the Italian submariners were not as ineffective as often surmised.[6]:423-425 However, he also acknowledges that this does not change the fact that Italy's participation in the Battle of the Atlantic was not a success (neither was Germany's), and that its strategic significance was small (not surprisingly, as the number of Italian submarines that operated in the Atlantic was 30 at its peak, whereas the Kriegsmarine committed over 1,000 submarines to the battle of the Atlantic between 1939 and 1945).[6]:424

Overall, the Italian submarines sank 109 allied merchant ships totalling 601,425 tons, and suffered the loss of 16 boats.[9]

German U-boat activities[edit]

Remains of U-boat pens in Bordeaux (2009)

Admiral Dönitz decided during the summer of 1941 to build protective U-boat pens in Bordeaux. Construction began in September 1941. Constructed of reinforced concrete, 245 m (804 ft) wide, 162 m (531 ft) deep, and 19 m (62 ft) high, with a roof above the pens 5.6 m (18 ft 4 in) thick, and 3.6 m (11 ft 10 in) thick above the rear servicing area.

On 15 October 1942, the 12th U-boat Flotilla was formed at Bordeaux by the Kriegsmarine under the command of Korvettenkapitän Klaus Scholtz; the first U-boat to use the bunker was U-178 on 17 January 1943.

End of operations[edit]

The base was bombed by the British on several occasions, especially in 1940 and 1941, but no significant damage was suffered, except for the sinking of the barracks ship Usaramo;[10] the base was indirectly attacked by Operation Josephine B in June 1941, a raid to destroy the electricity substation that served the base.[11]

The remaining BETASOM boats ended their last offensive patrol in the late spring of 1943, after which seven BETASOM submarines were adapted to carry critical matériel from the Far East (Bagnolini, Barbarigo, Comandante Cappellini, Finzi, Giuliani, Tazzoli, and Torelli). Two of these were sunk by the Allies, two were captured in the Far East by the Germans after the September 1943 Italian Surrender and used by them and a fifth was captured in Bordeaux by the Germans, but not used.[12]

After the Italian Armistice in September 1943 the base was seized by the Germans; some of the Italian personnel joined the Germans independently of the Italian Social Republic. During this period the Italian postage stamps on hand were overprinted to show loyalty to Mussolini's rump state.[13]

The last two remaining U-boats left Bordeaux in August 1944, three days before the Allies occupied the base on 25 August; the last remaining German naval personnel attempted to march back to Germany but were captured by US forces on 11 September 1944.

List of submarines operating from BETASOM[edit]

In 1940, all twenty-eight Italian submarines which were to be based at BETASOM initially had to sail from bases on the Mediterranean Sea and transit the Straits of Gibraltar to reach the Atlantic Ocean. All twenty-eight did this successfully without incident.

In 1941, another four Italian submarines based in Italian East Africa (Africa Orientale Italiana, or AOI) reached the base after the fall of that colony during the East African Campaign. All four had to travel around the Cape of Good Hope to get to BETASOM.

Date of arrival at Bordeaux from the Mediterranean in 1940:[14][6]:439-470,690-691

  • 4 September Malaspina (6 patrols, 3 ships sunk totalling 16,384 GRT, lost with all hands in September 1941)
  • 8 September Barbarigo (11 patrols, 7 ships sunk totalling 39,300 GRT, sunk with all hands by planes in June 1943 after conversion into transport submarine)
  • 10 September Dandolo (6 patrols, 2 ships sunk totalling 6554 GRT, returned to the Mediterranean in June–July 1941)
  • 29 September Marconi (6 patrols, 7 ships sunk totalling 19,887 GRT, lost with all hands in September 1941)
  • 29 September Finzi (10 patrols, 5 ships sunk totalling 30,760 GRT, converted into transport submarine and captured after the Italian armistice)
  • 30 September Bagnolini (11 patrols, 2 ships sunk totalling 6926 GRT, converted into transport submarine and captured after the armistice)
  • 30 September Giuliani (this boat was transferred for a time to Gdynia to train Italian submariners in Uboattactics; 3 patrols, 3 ships sunk totalling 13,603 GRT, converted into transport submarine and captured at the armistice)
  • 3 October Emo (6 patrols, 2 ships sunk totalling 10,958 GRT, returned to the Mediterranean in August 1941)
  • 5 October Faà di Bruno (2 patrols, no ships sunk, lost with all hands in October 1940)
  • 5 October Tarantini (2 patrols, no ships sunk, sunk by HMS Thunderbolt on 15 December 1940)
  • 5 October Torelli (12 patrols, 7 ships sunk totalling 42,871 GRT, converted into transport submarine and captured after the armistice)
  • 6 October Baracca (6 patrols, 2 ships sunk totalling 8553 GRT, sunk by HMS Croome on 8 September 1941)
  • 6 October Otaria (8 patrols, 1 ship sunk of 4662 GRT, returned to the Mediterranean in September 1941)
  • 22 October Glauco (5 patrols, no ships sunk, sunk by HMS Wishart on 27 June 1941)
  • 23 October Calvi (8 patrols, 6 ships sunk totalling 34,193 GRT, sunk by HMS Lulworth on 15 July 1942)
  • 24 October Argo (6 patrols, 1 ship sunk of 5066 GRT, returned to the Mediterranean in October 1941)
  • 24 October Tazzoli (9 patrols, 18 ships sunk totalling 96,650 GRT, converted into transport submarine and lost with all hands in May 1943)
  • 31 October Leonardo Da Vinci (120,243 GRT, the best performing non-German submarine in World War II)
  • 2 November Veniero (6 patrols, 2 ships sunk for 4987 GRT, returned to the Mediterranean in August 1941)
  • 4 November Nani (3 patrols, 2 ships sunk totalling 1,939 GRT, lost with all hands in January 1941)
  • 5 November Comandante Cappellini (12 patrols, 5 ships sunk totalling 31,648 GRT, converted into transport submarine and captured after the armistice)
  • 18 November Brin (5 patrols, 2 ships sunk totalling 7241 GRT, returned to the Mediterranean in August–September 1941)
  • 28 November Morosini (9 patrols, 6 ships sunk totalling 40,933 GRT, lost with all hands in August 1942)
  • 2 December Marcello (3 patrols, 1 ship sunk of 1550 GRT, lost with all hands in February 1941)
  • 18 December Bianchi (4 patrols, 3 ships sunk totalling 22,266 GRT, sunk with all hands by HMS Tigris on 4 July 1941)
  • 25 December Velella (4 patrols, no ships sunk, returned to the Mediterranean in August 1941)
  • 26 December Mocenigo (4 patrols, 1 ship sunk of 1253 GRT, returned to the Mediterranean in August 1941)

Transferred from the Red Sea Flotilla during the summer of 1941:[6]:439-470,690-691

  • 7 May Archimede (3 patrols, 2 ships sunk totalling 25,629 GRT, sunk by planes on 15 April 1943)
  • 7 May Guglielmotti (no patrols under Betasom, returned to the Mediterranean in September–October 1941)
  • 9 May Galileo Ferraris (1 patrol, no ships sunk, sunk by HMS Lamerton on 25 October 1941)
  • 19 May Perla (coastal submarine, no patrols under Betasom, returned to the Mediterranean in September–October 1941)

In 1941, it was decided to return some of the boats to the Mediterranean. Perla, Guglielmotti, Brin, Argo, Velella, Dandolo, Emo, Otaria, Mocenigo, and Veniero Glauco made the passage but Glauco was sunk by the British Royal Navy. Cagni was transferred in 1942.

Post-World War II[edit]

The submarine pens have proved to be infeasible to demolish due to their massive reinforced construction which had been designed to withstand aerial bombardment; as of 2010, after conversion several years previously, approximately 12,000 m2 (130,000 sq ft) of the 42,000 m2 (450,000 sq ft) building are open to the public as a cultural centre for the performing arts, exhibitions, and evening events.[15]


  1. ^ "B" (for Bordeaux) is rendered with BETA and SOM is an abbreviation for sommergibile (plural sommergibili) which is – along with sottomarino – an Italian word for submarine
  2. ^ D'Adamo, Cristiano (1996–2008). "BETASOM". REGIAMARINA. Retrieved 13 March 2012.
  3. ^ a b c Ireland, Bernard (2003). Battle of the Atlantic. Barnsley, UK: Pen & Sword Books. pp. 51–52. ISBN 1-84415-001-1.
  4. ^ Thirty two submarines operated in the Atlantic for the Italian Navy and sank 109 Allied ships for a total of 593,864 tons.
  5. ^
  6. ^ a b c d e f g Giorgerini, Giorgio (2002). Uomini sul fondo : storia del sommergibilismo italiano dalle origini a oggi [Men on the bottom: the story of Italian submersibles from the beginning to today] (in Italian). Milano: Mondadori. ISBN 9788804505372.
  7. ^ Clay Blair, Hitler's U-boat War: The Hunters, 1939-1942, p.740
  8. ^ The US Navy's most successful submarine, USS Tang, sank 116,454 GRT, while HMS Upholder, the Royal Navy's most successful submarine, sank 93,031 GRT of shipping.
  9. ^ Piekałkiewicz, Janusz. Sea War: 1939-1945. Blandford Press, London - New York, 1987, pg. 106, ISBN 0-7137-1665-7
  10. ^ D'Adamo, Cristiano (1996–2007). "The Bombardments of Bordeaux and the Italian submarine base "BETASOM"". REGIAMARINA. Archived from the original on 7 February 2009. Retrieved 7 Jan 2009.
  11. ^ Foot, M.R.D. (1966). SOE in France. HMSO. pp. 157–159.
  12. ^ Rosselli, Alberto. "Italian Submarines and Surface Vessels in the Far East: 1940-1945". Comando Supremo. Archived from the original on 3 February 2009. Retrieved 7 Jan 2009.
  13. ^ Stamps of the Italian Socialist Republic - The Atlantic Base
  14. ^ "Regia Marina Italiana". Cristiano D'Adamo. Retrieved 2012-07-31.
  15. ^ "Bordeaux: Base sous-marine". Retrieved 5 January 2019.

External links[edit]