[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.

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.

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.

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.

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.

[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.

[29] 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.

[38] Allied armies advancing through North Africa and Sicily constructed a system of airfields increasing the frequency of U-boat detection by aircraft.

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] 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.

Surviving U-boats at Toulon were scuttled when Operation Dragoon, (the invasion of southern France), closed the 29th Flotilla base on 15 August 1944.

[56] 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.