Although this movie is supposed to be based on fact, the scene in which the spy breaks into the Germany Navy code room is fiction. In fact, the British code breakers at Bletchley Park had already broken the German codes and knew how to pinpoint Atlantis. However, to keep the Germans from knowing this, various cover stories were invented during the war. This error is not the fault of the film makers as this information wasn't revealed to the general public until 1974, 14 years after this movie was made.
Around 00:03:10, it is mentioned the destroyer HMS Hector was sunk. The Hector was sunk on April 5, 1942 by Japanese planes when it was docked in Colombo, Ceylon, long after the time period encompassed by this movie.
At 00:04:10, Captain Malcolm ??? mentioned the Gloucester Castle as a passenger ship that pulled into Cape Town late. The HMHS Gloucester Castle was a hospital ship and would not be carrying passengers. The Gloucester Castle was sunk in 1941 by the German raider Michael. It was a passenger ship. It had been a hospital ship during WW1.
At 00:04:33, The SS Christina is mentioned to have been attacked. Later the movie shows a life ring, with its name and the registered port of Bristol, floating among the flotsam. The SS Christina is a fictitious ship.
At 00:06:39, the Atlantis is posing as the Ka Shii Maru. In reality, Atlantis posed as the Japanese ship "Kasii Maru" and was spotted by the "City of Exeter" on May 2, 1940.
The third ship the Atlantis sank in reality was the "City of Baghdad". Early in the movie, the ship shown to be sunk was the "City of Liverpool", a ship that Atlantis did not sink. It is probable the director changed the name for the movie.
At 00:15:10, Admiral Russell (Charles Laughton) lists the names of eight ships that have been sunk by the auxiliary cruiser "Atlantis". The ships Admiral Russell lists, not in chronological sinking (or captured) order are: (Name, Sunk/Captured Date) Mandasor, January 24, 1941; Trafalgar, May 24, 1941; Commissaire Ramel, September 20, 1940; Athelking, September 9, 1940; Benarty, September 10, 1940; Speybank, January 31, 1941; Rabaul, May 14, 1941; Silvaplana, September 10, 1941. Admiral Russell ends the list with the ship "Silvaplana" which was the last ship to have been captured or sunk by the Atlantis on September 10, 1941. Atlantis was then sunk by the HMS Devonshire on November 22, 1941. The movie continues to show the Atlantis sinking ships after the stated capture of the Silvaplana, the last ship it either captured or sank.
At 00:19:14, the Atlantis is attacking the Abdullah, a ship it did not attack in reality. The director could be substituting the Abdullah which contains what appears to be Egyptian passengers for the "Zamzam", an Egyptian passenger liner.
At 00:33:08, torpedoes from the Atlantis hits a warship. There is no record of the Atlantis sinking a warship.
At 00:45:09, Admiral Russell mentions that the Atlantis has been at sea for 500 days. Atlantis was sunk on its 602 day at sea on November 22, 1941. That sets the time of Admiral Russell's dialogue on August 12, 1941
At 01:04:02, POW's from the "Abdullah" (in reality the "Zamzam") are transferred to another ship, the "Pine Creek", introduced at 00:45:32. In reality, it was the captured Yugoslavian steamboat "Durmitor" which made landfall in Warsheikh, north of Mogadishu, on November 22, 1940, long before the time line of the movie. This depiction is more in line with the time line of the movie, when in reality, POW's were transferred to the German ship "Dresden".
At 01:12:27, Admiral Russell gives the position where the Atlantis will be providing fuel to U-126 at position "Lily". He states it is at 23° 30' S, 75° 10' E. This is in the middle of the Indian Ocean. It would be impossible to reach that spot in such a short time from the position that showed just three minutes early in the movie at 01:09:12. At this time, the ship is in snow at anchor in what appears to be a fjord during November. This would place the ship in the North Atlantic, possibly Norway. The other location for the snow scene would be that the ship was close to Antarctica during the southern summer. This would also be too far away from the actual sinking location. In reality, the ship was sunk in the middle of the Atlantic at 4° 12' S, 18° 42' W.
At 01:16:10, HMS Devonshire approached quite close to the Atlantis. In reality, Devonshire never approached more than eight nautical miles. It would be a small shape on the horizon as viewed from the Atlantis. Eight nautical miles was outside the range of the Atlantis's 5.9" guns but placed the Atlantis within the range of HMS Devonshire's 8" guns. After determining that the Atlantis posing as the Dutch ship Polyphemus was not confirmed by the Admiralty, the Devonshire opened fire.
At 01:17:34, the position given still puts the ships in the Indian Ocean at 32° S, 62° E. This is incompatible with the actual position that the Atlantis was sunk.
At 00:04:10, Captain Malcolm ??? mentioned the Gloucester Castle as a passenger ship that pulled into Cape Town late. The HMHS Gloucester Castle was a hospital ship and would not be carrying passengers. The Gloucester Castle was sunk in 1941 by the German raider Michael. It was a passenger ship. It had been a hospital ship during WW1.
At 00:04:33, The SS Christina is mentioned to have been attacked. Later the movie shows a life ring, with its name and the registered port of Bristol, floating among the flotsam. The SS Christina is a fictitious ship.
At 00:06:39, the Atlantis is posing as the Ka Shii Maru. In reality, Atlantis posed as the Japanese ship "Kasii Maru" and was spotted by the "City of Exeter" on May 2, 1940.
The third ship the Atlantis sank in reality was the "City of Baghdad". Early in the movie, the ship shown to be sunk was the "City of Liverpool", a ship that Atlantis did not sink. It is probable the director changed the name for the movie.
At 00:15:10, Admiral Russell (Charles Laughton) lists the names of eight ships that have been sunk by the auxiliary cruiser "Atlantis". The ships Admiral Russell lists, not in chronological sinking (or captured) order are: (Name, Sunk/Captured Date) Mandasor, January 24, 1941; Trafalgar, May 24, 1941; Commissaire Ramel, September 20, 1940; Athelking, September 9, 1940; Benarty, September 10, 1940; Speybank, January 31, 1941; Rabaul, May 14, 1941; Silvaplana, September 10, 1941. Admiral Russell ends the list with the ship "Silvaplana" which was the last ship to have been captured or sunk by the Atlantis on September 10, 1941. Atlantis was then sunk by the HMS Devonshire on November 22, 1941. The movie continues to show the Atlantis sinking ships after the stated capture of the Silvaplana, the last ship it either captured or sank.
At 00:19:14, the Atlantis is attacking the Abdullah, a ship it did not attack in reality. The director could be substituting the Abdullah which contains what appears to be Egyptian passengers for the "Zamzam", an Egyptian passenger liner.
At 00:33:08, torpedoes from the Atlantis hits a warship. There is no record of the Atlantis sinking a warship.
At 00:45:09, Admiral Russell mentions that the Atlantis has been at sea for 500 days. Atlantis was sunk on its 602 day at sea on November 22, 1941. That sets the time of Admiral Russell's dialogue on August 12, 1941
At 01:04:02, POW's from the "Abdullah" (in reality the "Zamzam") are transferred to another ship, the "Pine Creek", introduced at 00:45:32. In reality, it was the captured Yugoslavian steamboat "Durmitor" which made landfall in Warsheikh, north of Mogadishu, on November 22, 1940, long before the time line of the movie. This depiction is more in line with the time line of the movie, when in reality, POW's were transferred to the German ship "Dresden".
At 01:12:27, Admiral Russell gives the position where the Atlantis will be providing fuel to U-126 at position "Lily". He states it is at 23° 30' S, 75° 10' E. This is in the middle of the Indian Ocean. It would be impossible to reach that spot in such a short time from the position that showed just three minutes early in the movie at 01:09:12. At this time, the ship is in snow at anchor in what appears to be a fjord during November. This would place the ship in the North Atlantic, possibly Norway. The other location for the snow scene would be that the ship was close to Antarctica during the southern summer. This would also be too far away from the actual sinking location. In reality, the ship was sunk in the middle of the Atlantic at 4° 12' S, 18° 42' W.
At 01:16:10, HMS Devonshire approached quite close to the Atlantis. In reality, Devonshire never approached more than eight nautical miles. It would be a small shape on the horizon as viewed from the Atlantis. Eight nautical miles was outside the range of the Atlantis's 5.9" guns but placed the Atlantis within the range of HMS Devonshire's 8" guns. After determining that the Atlantis posing as the Dutch ship Polyphemus was not confirmed by the Admiralty, the Devonshire opened fire.
At 01:17:34, the position given still puts the ships in the Indian Ocean at 32° S, 62° E. This is incompatible with the actual position that the Atlantis was sunk.
Near the end, the recon aircraft overflying the ship is a Grumman S2 ASW aircraft. The S2 went into service in the US Navy in the early 1950s, and was retired from the US Navy in 1976. Major clues are the Magnetic Anomaly Detector probe protruding from the aircraft tail, the ESM pod behind the pilot's position, and the floodlight on the outboard on the leading edge of the starboard wing.