[jaxa]

Yes, you have right Hitman, some Uboots were transferred to Baltic Sea before Operation Barbarossa, but they haven't many occasions for fighting. In 1944 some Uboots fighted with Russian Baltic Fleet. Baltic Sea was one of two places, where Uboot commanders used main gun beyond 1942 (another place was Arctic Sea, against Russians too). The biggest problem for Uboots on Baltic Sea were mines, deployed by both sides of the conflict.