 The class was built by Germaniawerft of Kiel to their 506d design as the U-7"-class for the Austro-Hungarian Navy.The five boats were sold to the Imperial Germany Navy at the beginning of World War I when it was thought impossible for the submarines to reach the Mediterranean for delivery to Austria-Hungary.The Austro-Hungarian Navy, after competitively evaluating six submarines of three foreign designs, selected the Germaniwerft 506d or Type UD design over a design from Whitehead & Co. for the "U-7" class.