Sources differ and list 25–26 cases of German submarines serviced in Spanish ports documented,Monte, Peter, U-Boats in Spain, [in:] Deutsches U-Boot Museum service; see also Juan J. Díaz Benítez, The Etappe Kanaren: A case study about the secret supply of the German Navy in Spain during the Second World War, [in:] International Journal of Maritime History 30/3 (2018) taking place between January 1940 and February 1944: 5 in 1940, 16 in 1941, 3 (2) in 1942, none in 1943 and 1 (0) in 1944.Díaz Benítez 2016, p. 16, see also Monte Most were scheduled operations and 3 were emergency cases. The ports used were Vigo (7–8), Las Palmas (6), Cádiz (6) and El Ferrol (5). Overall, there were 1,508 tons of gas, oil and 37.1 tons of heavy oil pumped; in most cases there was also lubricants, water and food delivered, in some cases navigation charts and first-aid kits. Also 3 cases that were delivered are torpedoes.Díaz Benítez 2016, p. 16 In a few cases injured or sick German sailors were taken off the ship. Almost all cases were overnight operations, though two emergency repairs took a few days. There were four German supply ships (Thalia, Bessel, Max Albrecht and Corrientes) involved. In one case the replenishment operation was abandoned, as it turned out that the submarine in question was damaged and unfit for the process.Monte The Corrientes was the target of a limpet mine attack while at port in Las Palmas on 9 May 1940, but the damage was minor and she was back in service a few weeks later.
