13th U-boat Flotilla

The 13th U-boat Flotilla (German 13. Unterseebootsflottille) was a World War II U-boat unit of Nazi Germany's Kriegsmarine stationed in Trondheim, Norway. The emblem of the unit was a cross with a Viking ship in the middle.

History
In 1941, construction of the DORA 1 submarine base started in Trondheim. Two years later, in June 1943, it was handed over to the flotilla commander, Korvettenkapitän (later Fregattenkapitän) Rolf Rüggeberg. The 13th submarine flotilla was a front line unit, and a total of 55 Type VIIC and VIIC/41 served with it until the end of the war in May 1945.