'Moro' was a German and Spanish agreement making it possible for U-boats and especially their supply vessels to use Spanish ports for refuelling and reprovisioning (1940/41).

On 30 January 1940, for example, the 1,122-ton tanker Thalia was to have refuelled U-44 in Cadiz Bay, but in the absence of that boat refuelled U-25 in an operation lasting four hours.