The coastal Type II U-Boats were became the first vessels of this class, that were built in Germany after the end of WWI. In the end of 1942 six Type IIB U-Boats were transferred to the Black Sea. They were used there up to September 1944.
U-boats type XXIII belonged to the new generation of German WWII submarines. Designers paid the main attention to increase of speed and range in the submarine position. To the mid 1943 there have designed projects of “electric subs” – ocean type XXI and little coastal type XXIII.