Ermland

Germany's lack of overseas bases made supply ships and tankers essential for sustained naval operations in the Atlantic. The Kriegsmarine trained for underway replenishment during the 1930s and employed its supply network extensively during the Spanish Civil War. In spring 1939, warships and auxiliaries, including Gneisenau, conducted a major exercise in the central Atlantic that rehearsed procedures used during the first years of World War II.

The supply network reached its greatest operational importance during Operation Rheinübung in May 1941. After the loss of Bismarck, the Royal Navy located and captured or sank many of the German support ships deployed in the Atlantic.

Alongside converted civilian tankers, the Kriegsmarine ordered the purpose-built Dithmarschen class. Five of the nine planned ships entered service. Each could carry 7,933 tons of fuel, 972 tons of ammunition, 790 tons of provisions and 100 tons of spare parts. They also carried towing equipment for assisting damaged warships.

Plans to employ the ships as auxiliary cruisers were abandoned because combat would have exposed their vulnerable cargo and replenishment equipment. Two members of the class survived the war and continued in British and United States service into the 1950s.

Ermland broke through the Denmark Strait in October 1940 and later supplied Scharnhorst and Gneisenau during Operation Berlin. In May 1941 the ship sailed from La Pallice to assist the damaged Bismarck but was recalled after the battleship sank. A mine damaged Ermland in September 1942, and Allied bombs broke the vessel in two near Nantes a year later. The remains were finally sunk as a blockship in August 1944.