The Milk Cows: The U-Boat Tankers at War 1941 - 1945

During the Second World War the Germans developed a specially adapted U—boat oil tanker with two aims. First, by refueling the attack U—boat fleet their range of operations and duration of patrol could be significantly increased. Secondly, these underwater tankers were far more likely to avoid detection than surface support ships.

The submarine tankers, affectionately known as Milk Cows, were regarded by both the Germans and the Allies as the most important element of the U—boat fleet. Allie...