High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! German submarine U-961 was a Type VIIC U-boat built during World War II. U-961 was constructed at Hamburg during 1942 and 1943, completing her working-up cruises in the Baltic Sea in the spring of 1944. Due to extensive modifications and shortages of supplies during her construction and training, U-961 took nearly two years to be ready for active service, an exceptionally long time.