High Quality Content by WIKIPEDIA articles! The German Type IXA submarine was a sub-class of the German Type IX submarine built by the German Navy (Kriegsmarine) between 1937 and 1938. These U-boats were designed between 1935 and 1936 and were intended to be fairly large ocean-going submarines. The inspiration for the Type IXA submarine came from the German Type IA submarine, which had a similar diving depth and identical submerged horsepower.