The historical U-4 submarine was a Type IIA U-boat ordered for construction in February 1935, launched that same July, and commissioned on August 17th 1935.  Her first captain was Oberleutnant zur See Hannes Weingärtner who commanded the ship for two years, overseeing primarily training exercises.  In August 1939, the submarine was placed on war footing under Kapitänleutnant Harro von Klot-Heydenfeldt who commanded the vessel during her first two war patrols and sunk three merchant vessels. 

 

In April 1940, under the command of Oberleutnant Heinz-Otto Schultze, the submarine supported operations during the invasion of Norway.  In July 1940, the submarine was reassigned as a training vessel and spent the remainder of the war attached to various training flotillas, most notably the 21st U-boat Flotilla based at Kiel and later Pillau.

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U-4's final commander was Oberleutnant Hubert Rieger who oversaw the decommissioning of the vessel in August 1944.  The submarine was then stripped of components and then broken apart for scrap metal in early 1945.