Factual error: The film was released in 1958 but depicts a 1943 World War II mission in the Pacific by a US submarine capatain played by Clark Gable and his first officer played by Burt Lancaster. In two separate scenes the crew listens to a "Tokyo Rose" broadcast on radio and the background music is "Kiss Me Once, Kiss Me Twice, It's Been a Long Long Time" by Sammy Cahn and Jule Styne. The song was not released until September 1945, one month AFTER the end of the war in the Pacific in August 1945. The song was famous for celebrating returning troops and therefore also makes no sense in the context of 1943.
Factual error: The Vikings raided England in the 9th and 10th centuries. The first castles were not built until post 1066. The castle in the film has rounded towers, crenellations and machicolations, which would date it at approximately 1300. That would tend to suggest that these Vikings were 400 or 500 years old, or that they had access to a time machine.
Other mistake: During training, when the men are running and the two British men come out of the bushes then shoot at the ground, there are 3 rows of bullets going past but only 2 guns being fired.
Continuity mistake: When Diestl and Hardenburg attempt their wild dash to the coast on the motorcycle, they pass the same wrecked Kubelwagen three times.