When Alfred is recovering in the hospital in Halifax, NS, in early 1945, he is handed a letter with a Canadian postal code in the address. But Canada did not introduce post codes until the 1970s.
When writing home to his family, Alfred tells them that he saw several albatrosses but as far as the story had gone, he had only been sailing in the North Atlantic and the Mediterranean and the albatross is native to the southern hemisphere and North Pacific. However, it is possible that he was flowering his letters for the sake of his children.
Several actors sport tattoos of modern design and body location, detracting from the otherwise historical accuracy of the film.