Goofs

When the Copperfin fires its aft torpedoes at the already burning aircraft carrier, the periscope view shows the carrier dead in the water. In the underwater shot, when the torpedoes are seen approaching the carrier, it is underway.

On the surface the submarine has no net cutter on its bow, but on the underwater scenes going into Tokyo harbor, the submarine has a net cutter.

The deck gun shifts from the foredeck to the afterdeck.

After the appendectomy conference in the crew's mess, Cassidy turns and goes through a watertight door leading to the crew's berthing space (you can see a few bunks through the open doorway). But in the next shot, he enters the control room, which is in the opposite direction from the berthing space.

When Cassidy is on the dock immediately prior to departure, boarding the boat, and addressing the crew, he is dressed in blues. As the Copperfin departs, he is on the bridge in khaki's.

When briefing the volunteers for the mission to infiltrate Japan, the captain tells them specific details of the Doolittle Raid. This is something that wouldn't happen due to standard operational security. The landing party would be told what information they were to gather and how to return it and themselves to their sub, but they would be given as little information as possible in the event they were captured.

Japanese soldiers board a truck to seek source of radio transmissions by a U.S. Navy shore party in Tokyo Bay. The truck has a left hand drive whereas Japanese vehicles have the steering wheel on the right hand side. Japanese drive on the left side of the road.

When the quartermaster is typing the notice for the crew stating their patrol area is Tokyo, the banner reads war patrol six.

There is no way the Copperfin could have made five war patrols in the first four months of the war (7 Dec 1941 to 1 Apr 1942). This is further supported when Wolf who has been on Copperfin on previous patrols is on shore leave after returning from a three month patrol. This would indicate Copperfin did her first four patrols in Dec 1941.

On more then one occasion the submarine is referred to as a ship, once by the captain himself. Apart from a brief effort by the US Navy in the 1950s to refer to submarines as ships, they have always been "boats" to the officers and crews who work on them.

When the Copperfin surfaces in the Aleutians to pick up the team, Tommy and Wolf bring up the .50 machine gun. Wolf mounts the weapon, then Tommy hands him the magazine which he mounts on the MG. He then pulls the charging handle and mans the gun as if it was ready for battle. Unfortunately, at no time did he open the feed mechanism on the weapon and start the ammo belt so pulling the charging handle did absolutely nothing.

When the infiltration team is in the cave, they are carrying lever action Winchester 30-30 rifles. This rifle was never issued to the Army, Navy or Marines field forces. The possible reason for this choice of rifle was that it was a popular pre-war choice by shooters all over the world including the Japanese.

By broadcasting in the Japanese language the American was trying to give the illusion that it was native spies who were doing the reporting. If the landing team had to use the rifles the Japanese would not think they were dealing with American infiltrators which the sound of military firearms would of gave away. Through out military history It was not unusual for special missions to use non-military weapons.

When the two torpedoes are fired at the Japanese boat, they exit the same tube in impossibly rapid succession, due to the same footage being used for both launches.

As the Copperfin enters Tokyo Bay following the crippled cruiser, the skipper orders the boat to rise to 60 feet, then 45 feet ("keel depth")be sure to clear the torpedo net. However, the shots of the submarine never show any changes in depth. At "keel depth", the top of the conning tower would be nearly breaking the surface.

Upon entering and exiting Tokyo Bay, the Copperfin is shown several times rising and falling with the sea floor, often coming within a few feet of it. However, without active sonar - which would mean immediate detection by the Japanese - there's no way they'd know the distance to the bottom to maneuver like this.

During the landing in Tokyo bay landing party are carrying 30-30 lever action Winchesters.They should be carrying M1 Garand or Thompson Sub Machine guns.

Seaman Tommy Adams (Robert Hutton) is embarrassed when it turns out that the incoming aircraft he saw turned out to be an albatross. However there were others on deck with him who could have corrected his mistake.

On Christmas morning, one of the crew mentions Christmas 1941 in the past tense, meaning that this is Christmas 1942 or later. After that, the boat supports Doolittle's Raid, which occurred 18 April 1942.

As the Copperfin is approaching their rendezvous in the Aleutians, they are submerged at periscope depth. The man on the sonar calls out depths of 1000 and 800 fathoms (6000 and 5400 feet respectively). The scene changes to show the boat moving submerged with the ocean bottom clearly visible only a couple of hull heights below. If the bottom were 5,400 feet below, it would not be visible sunlight only penetrates approximately 600 feet.

Gato type sub patrol was usually 75 days. The Copperfin left on Christmas day for mission to assist with the Doolittle Raid on Apr. 18th, which is 115 days out. Though there was a detour to pick up the Reserve Officer Ridgely, that was just a rendezvous with a seaplane. Food, fuel would be long gone before even arriving to Tokyo Bay.

When entering Toyko Harbor, the wrinkled side of the pool can be seen off-camera from the Copperfin.

In several underwater shots, wires can be seen attached to mock-up of miniature sub.

As the sub departs from S.F., passing under the G.G bridge, a mountain is seen behind the boat. There is no 'mountain' in that location. The only real mountain anywhere nearby is Mount Tamalpais (< 2,600 ft), and it is north of the bridge, which is off screen to the left.

Cassidy looks through the periscope from the sub and sees Mt Fuji as though it were right on the shoreline. You can only see the tip of Mt Fuji from sea level in Tokyo Bay and only on a clear day. Mt Fuji is 300 miles away in Kyoto.

Submarines deploying to the Western Pacific early in the war would depart and return to Pearl Harbor, not San Francisco. The range of a Gato Class submarine was around 11,000 miles while a round-trip from S.F. to Tokyo would be no less than 10,680 miles, leaving very little margin for error and maneuvering.

At one point near Japan the skipper asks about the direction and is told it's 050. This sounds like the boat is traveling generally east. Not likely if one is heading towards Japan from the NE.

When the Copperfin is in Tokyo Bay, a sweep of the bay is made through the periscope. Ships in the harbor and barrage balloons over several areas. The recon info could have been obtained in this manner, making the shore mission unnecessary.

In a fleet boat, there are at least 3 compartments (motor room, engine room, and after battery) between the after torpedo room and the control room. But in the flooded after torpedo room scene, when water is being emptied into the next compartment, the camera pans to give a look into that compartment, and we see the Captain, leaning on the chart table in the control room.

Before getting underway, Cdr. Cassidy goes to the dock phone to check on a call he was trying to place to his wife. The shore operator refers to him as "Captain Cassidy." The men on his submarine would call him "captain," but anyone not a member of the crew would refer to him by his actual rank of commander.

The captain says that the Japanese don't have a word for "love" in their language. The Japanese word for love is "ai."