The Henrys attend a dinner party with the President at which the news is received that the the Bismarck has been torpedoed by British Torpedo bombers and the next scene (supposedly the next day) is proceeded by a title card showing the date as May 2 1941. That's more than two weeks before the Bismarck began her short Atlantic cruise.
While the correct German equivalent of "wolf pack" would be "Wolfsrudel" and "wolf pack tactics" would translate as "Rudeltaktik", in the German-speaking sequences the "Rudel" is referred to as "Pack", which simply is the wrong German word (German "Pack" means "vermin").
At Byron's brother's barbecue, Byron offers to bottle feed his brother's infant child. After doing so, Byron sets the empty bottle down and its plain to see that its a plastic bottle. During this time frame, baby bottles were made of glass.
The command wording of the German-speaking scenes does not represent the Kriegsmarine slang of the time. E.g., the Commander of a U-Boat usually is no "Kommodore" (engl. "Commander"), but a "Kapitänleutnant" or "Kaleun".
Uss Devilfish SS 292 Balao-class submarine was''t yet build in 1941 she was launched on 30 may 1943 and commissioned 1 September 1944.
The German submarines sight the convoy shortly after sunrise in the north Atlantic, west of Iceland. That would translate to 9-10 o'clock in Berlin. So the radio call requesting instructions wouldn't reach the German High Command in the early morning hours.
During the secret August 1941 meetings between the British and Americans at least one Iowa Class Battleship (USS Missouri BB-63) appears in several shots, the USS Missouri was not at this meeting as it had not even been commissioned until 11 June 1944. In fact none of the Iowa Class Battleships had joined the fleet yet, the first one being the Iowa BB-61 commissioned 22 February 1943.
The US destroyer that Pug is on during the convoy is inaccurate in two ways. Its bow number is DD-445, which was the ID of the USS Fletcher which was not commissioned until June of 1942. Additionally, the ship has dual-gun mounts, which did not appear until the Sumner class destroyers which appeared even later in 1943. Neither could be escorting a convoy in 1941.
The convoy scene is set March 28, 1941. One of the U-boats confronting the convoy is the U-41. In reality, the U-41 was sunk over a year earlier off the coast of Ireland (February 5, 1940,)
The "Mare Island Navy Yard" is indicated in an on-screen title as being in San Francisco. The former Mare Island Naval Shipyard was in Vallejo, 25 miles from San Francisco.
Pug Henry Identifies the Bismarck as a "Pocket Battleship" which were smaller than battleships. The Bismarck was perhaps the largest European battleship ever built and truly a battleship. The Graf Spee, Sheer, and the Deutschland were Pocket battleships.