Mediterranean U-boat Campaign
Part of the Battle of the Mediterranean of the Second World War

U-617 aground near Mellila, Morocco, at position 35°23′N 3°16′W / 35.38°N 03.27°W / 35.38; -03.27 after British air attack on 12 September 1943
Date21 September 1941 to May 1944
Location35°N 18°E / 35°N 18°E / 35; 18Coordinates: 35°N 18°E / 35°N 18°E / 35; 18
Result Allied Victory
Belligerents
 Royal Navy
 Royal Australian Navy
 United States Navy
Other Allied navies
 Kriegsmarine
 Regia Marina
Strength
62 U-boats
Casualties and losses
95 merchant ships sunk
24 big warships sunk
62 U-boats lost

The Mediterranean U-boat Campaign lasted from about 21 September 1941 to 19 September 1944 during the Second World War. Malta was an active British base strategically located near supply routes from Europe to North Africa. Axis supply convoys across the Mediterranean Sea suffered severe losses, which in turn threatened the fighting ability of the Axis armies in North Africa. The Allies were able to keep their North African armies supplied. The Kriegsmarine tried to isolate Malta but later it concentrated its U-boat operations on disrupting Allied landing operations in southern Europe.[clarification needed]

Some 60 German U-boats made the hazardous passage into the Mediterranean Sea from 1941. Only one completed the journey both ways.[1][2] Karl Dönitz, the Commander-in-Chief, U-boats, Befehlshaber der Unterseeboote (BdU) was always reluctant to send his boats into the Mittelmeer but he recognised that natural bottlenecks such as the Straits of Gibraltar were more likely to result in shipping being found and attacked than relying on finding it in the vast Atlantic Ocean.

The U-boats were sent to assist the Italians, although many were attacked in the Strait of Gibraltar and nine were sunk while attempting the passage and ten more were damaged. The Mediterranean is a clear and calm body of water which made escape more difficult for the U-boats.[3] The Axis failed in their objective.

Prior Experience

The Kriegsmarine had acquired some knowledge of the area. Dönitz was an officer aboard UB-68 which had been sunk in the region in World War I.[4] U-boats had also served in the Spanish Civil War. The Republicans, with twelve submarines, opposed the Nationalists, who had none; the presence of German U-boats was most welcome. The first two vessels, U-33 and U-34, under the codename Training Exercise Ursula, left Wilhelmshaven on 20 November 1936. Both submarines sailed down the English Channel and slipped into the Mediterranean on the night of 27 November. They were soon in action, U-34 fired a single torpedo at a Republican destroyer in the evening of 1 December. The projectile missed, impacting on rocks. The boat, under Leutnant zur See Harald Grosse, tried again on 5 and 8 December, with an equal lack of success. U-33 fared no better; her commander was frustrated by the absence of target identification or defensive movement of his intended victims. Only one vessel was sunk by the U-boats, the Republican submarine C-3, which was attacked by U-34 on 12 December.

The early years

By October 1939, Dönitz had decided to use three longer-range boats to intercept the first Allied convoys of the war. U-25, U-26 and U-53 were to rendezvous southwest of Ireland before attempting to force the Straits and attack the convoys in the Mediterranean. Things went quickly wrong, U-25 was diverted to a convoy south-west of Lisbon. After an abortive torpedo attack on a steamer on 31 October, Viktor Schütze, U-25's commander, surfaced and proceeded to sink his target with fire from his deck gun. This course of action caused a crack in a vital part of the submarine, obliging the boat to return to Germany. U-53 ran low on fuel after shadowing a convoy in the Bay of Biscay and was also forced to return. U-26, was compelled by a combination of unsuitable weather, searchlights and British anti-submarine patrols, to abandon an attempt to lay mines near Gibraltar harbour. The boat sailed through the Straits on the surface and claimed but a solitary ship sunk in the Mediterranean. This 'sinking' was not confirmed by post-war analysis.

U-26 headed back through the Straits, arriving in Wilhelmshaven on 5 December 1939; the only U-boat to enter and leave the Mediterranean in the war.[5][2] This mission was summed-up in the BdU Kriegstagebuch (KTB) War Diary,

It was a mistake to send U-25, U-26 and U-53 into the Mediterranean. U-25 had to return before she ever got there, U-53 did not get through and U-26 hardly encountered any shipping worth mentioning. This patrol shows all the disadvantages of a long outward passage.|KTB[6]

Many attacks mentioned were gun actions or ramming, particularly at the eastern end of the Mediterranean. This was because the potential target was "unworthy or [a] difficult torpedo target".[7]

Afrika Korps

The 23rd U-boat Flotilla was established in September 1941 to intercept coastal shipping supplying Allied forces in the Siege of Tobruk.[8] U-boats patrolled the eastern Mediterranean from the 23rd flotilla base on Salamis Island in Greece. On 7 December, control of the 23rd Flotilla was transferred from Kernével to The Commander in Chief in the South (Oberbefehlshaber Süd, OB Süd) Albert Kesselring. Additional bases were established in Pula in Croatia and La Spezia in northern Italy as more U-boats were ordered to the Mediterranean, until focus shifted to the western Atlantic through the Second Happy Time.[9]

Second Happy Time

La Spezia became headquarters when the Mediterranean U-boats were reorganized as the 29th U-boat Flotilla in May 1942.[28] No more U-boats were assigned to the Mediterranean from mid-January to early October 1942 as opportunities along the east coast of North America seemed more productive while the Afrika Korps was successfully advancing on Egypt. The 29th flotilla focused on convoys supplying Malta and British forces on the Egyptian coast. For sustained operations, U-boats spent approximately one-third of the time on patrol stations, one-third in transit to and from base for routine provisioning and refueling, and one-third undergoing major overhaul or battle repair. 29th flotilla target strength of twenty U-boats enabled a routine patrol strength of three U-boats from Salamis in the eastern Mediterranean, and three from La Spezia in the western Mediterranean. Loss of U-372 and U-568 in twelve-hour sustained attacks demonstrated vulnerability of independent U-boat patrols to a team of destroyers which could hunt a submerged U-boat to exhaustion of air and battery power, rather than moving on after a few attacks.[29]

Allied invasion of North Africa

Main article: Operation Torch

More U-boats were assigned to the 29th flotilla when improved anti-submarine warfare (ASW) measures along the east coast of North America ended the Second Happy Time. When a Short Sunderland found U-559, the aircraft summoned five destroyers able to maintain contact and drop 150 depth charges over ten hours, until the submarine attempted to sneak away on the surface at night. Waiting destroyers open fire as soon as the U-boat surfaced and the U-boat crew abandoned ship. The Royal Navy boarded the sinking U-boat and recovered German code documents before U-559 sank.[38]

The Second Battle of El Alamein prompted a concentration of U-boats in the western Mediterranean, in anticipation of Allied amphibious invasion. Five U-boats made contact with Operation Torch convoys, and two wolfpacks assembled near the invasion points. U-73, U-81, U-458, U-565, U-593, U-595, U-605 and U-617 assembled around Oran as Gruppe Delphin (Group Dolphin); U-77, U-205, U-331, U-431, U-561 and U-660 assembled around Algiers as Gruppe Hai (Group Shark). Five U-boats were sunk opposing the invasion.[38]

Replacement U-boats

Axis defeat in Tunisia

Allied armies advancing through North Africa and Sicily constructed a system of airfields increasing the frequency of U-boat detection by aircraft. The 29th Flotilla focused on western Mediterranean convoys supplying Allied troops but three U-boats were based at Salamis to maintain an eastern Mediterranean patrol presence, forcing the Allies to disperse their ASW efforts. On 1 August 1943 the 29th Flotilla shifted its headquarters from La Spezia to Toulon where it could use the former French naval base for patrols in the western Mediterranean.[51]

Replacements

After the Italian armistice

As Allied escort forces in the Mediterranean became more numerous, the tactic of hunting a detected U-boat to exhaustion was given the name Swamp and used with increasing frequency. U-boats launched G7es torpedoes with passive homing against destroyers, but were unable to cope with a team of escorts. U-boats remaining in port were subjected to USAAF air raids from newly constructed airfields. Surviving U-boats at Toulon were scuttled when Operation Dragoon, (the invasion of southern France), closed the 29th Flotilla base on 15 August 1944. Three U-boats remained at Salamis until Allied forces reached them on 19 September 1944.[56]

Replacements

Success and failure

HMS Barham explodes as her 15-inch magazine ignites, 25 November 1941.
HMS Barham explodes as her 15-inch magazine ignites, 25 November 1941.

The Germans sank 95 Allied merchant ships totalling 449,206 tons and 24 Royal Navy warships including two carriers, one battleship, four cruisers and 12 destroyers at the cost of 62 U-boats. Noteworthy successes were the sinking of HMS Barham, Ark Royal, Eagle and Penelope.

U-boats sunk by Allied submarines

Four U-boats were sunk by Allied submarines in the Mediterranean:

See also

References

  1. ^ Paterson (2007) pp. 19, 182
  2. ^ a b "U-26". Guðmundur Helgason. Retrieved 29 October 2020.
  3. ^ Paterson, 11th photo caption, between pages 74 and 75
  4. ^ Paterson, p. 6
  5. ^ Paterson, pp. 19, 182.
  6. ^ Paterson, p. 20
  7. ^ Paterson, 23rd photo caption between pages 74 and 75
  8. ^ "23rd Flotilla". Guðmundur Helgason. Retrieved 20 June 2012.
  9. ^ a b c d Blair (1996) pp.395-404
  10. ^ a b c d e f g h i j k l m n o p q r s t Blair (1996) pp.735–736
  11. ^ a b c "Ships hit by U-559". Guðmundur Helgason. Retrieved 20 June 2012.
  12. ^ a b c "Ships hit by U-97". Guðmundur Helgason. Retrieved 20 June 2012.
  13. ^ Blair (1996) pp.399&736
  14. ^ a b Blair (1996) pp.403, 735–736
  15. ^ Blair (1996) pp.396–397, 736
  16. ^ a b c "Ships hit by U-431". Guðmundur Helgason. Retrieved 20 June 2012.
  17. ^ Blair (1996) pp. 400, 736
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  19. ^ a b c "Ships hit by U-562". Guðmundur Helgason. Retrieved 20 June 2012.
  20. ^ a b "Ships hit by U-652". Guðmundur Helgason. Retrieved 20 June 2012.
  21. ^ a b c d e "Ships hit by U-453". Guðmundur Helgason. Retrieved 20 June 2012.
  22. ^ Blair (1996) pp. 403, 716–719
  23. ^ Taylor (1966) p.124
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  25. ^ a b c "Ships hit by U-77". Guðmundur Helgason. Retrieved 20 June 2012.
  26. ^ "Ships hit by U-573". Guðmundur Helgason. Retrieved 20 June 2012.
  27. ^ a b c Taylor (1966) p.132
  28. ^ "29th Flotilla". Guðmundur Helgason. Retrieved 20 June 2012.
  29. ^ a b c d e f g h i Blair (1996) pp.645–654
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  31. ^ "Ships hit by U-83". Guðmundur Helgason. Retrieved 20 June 2012.
  32. ^ Blair (1996) pp.553–554
  33. ^ Taylor (1966) p.116
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  35. ^ a b c "Ships hit by U-375". Guðmundur Helgason. Retrieved 20 June 2012.
  36. ^ a b "Ships hit by U-561". Guðmundur Helgason. Retrieved 20 June 2012.
  37. ^ a b c "Ships hit by U-565". Guðmundur Helgason. Retrieved 20 June 2012.
  38. ^ a b c d e f g Blair (1998) pp.81–103
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  40. ^ a b c d e f g h i j k l Blair (1998) pp.208–217
  41. ^ a b c "Ships hit by U-371". Guðmundur Helgason. Retrieved 20 June 2012.
  42. ^ a b c d e f g h i j k l m n o p q r s t Blair (1998) pp.735–751
  43. ^ a b c "Ships hit by U-593". Guðmundur Helgason. Retrieved 21 June 2012.
  44. ^ a b "Ships hit by U-617". Guðmundur Helgason. Retrieved 21 June 2012.
  45. ^ a b c "Ships hit by U-407". Guðmundur Helgason. Retrieved 21 June 2012.
  46. ^ a b c "Ships hit by U-596". Guðmundur Helgason. Retrieved 21 June 2012.
  47. ^ a b "Ships hit by U-755". Guðmundur Helgason. Retrieved 21 June 2012.
  48. ^ a b "Ships hit by U-380". Guðmundur Helgason. Retrieved 21 June 2012.
  49. ^ "Ships hit by U-443". Guðmundur Helgason. Retrieved 21 June 2012.
  50. ^ "Ships hit by U-602". Guðmundur Helgason. Retrieved 21 June 2012.
  51. ^ Blair (1998)pp. 216–217, 412
  52. ^ a b c d e Blair (1998) pp.375–381
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  54. ^ a b "Ships hit by U-410". Guðmundur Helgason. Retrieved 21 June 2012.
  55. ^ "Ships hit by U-409". Guðmundur Helgason. Retrieved 29 October 2020.
  56. ^ a b c d e f g h i Blair (1998) pp.518–526
  57. ^ a b c Blair (1998) pp.455–458
  58. ^ Taylor (1966) p.125
  59. ^ "Ships hit by U-616". Guðmundur Helgason. Retrieved 21 June 2012.
  60. ^ a b Blair (1998) pp.411–414
  61. ^ "Ships hit by U-223". Guðmundur Helgason. Retrieved 21 June 2012.
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  63. ^ "Ships hit by U-230". Guðmundur Helgason. Retrieved 21 June 2012.
  64. ^ Taylor (1966) p.119
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Bibliography