Factual error: In the scene where the Captain (Gene Hackman) is getting ready to address the crew, the Chief of the Boat (an enlisted man) is briefly shown barking orders to the crew wearing a combination cover with an officer's golden chin strap. A Chief Petty Officer wears a black chin strap. Contrary to popular belief, it's not illegal to wear an accurate uniform on film, in fact the military offer their help to ensure uniforms are accurate: http://www.defenselink.mil/news/NewsArticle.aspx?ID=516, so that's not the reason.

Continuity: After the submarine is hit by the first missile, all the crew are picking up things that have fallen down in the underwater turbulence. Then when the captain returns to his personal cabin, all his belongings (most noticeably on his desk) are all in position as though the attack never happened.

Factual error: At one point, the US sub's starboard (right) side is shown to have an American flag painted on the hull near the bow. The flag's blue field is at top/left when on this side of any vehicle, it should be at top/right. Proper display of the flag requires the blue field always be located 'forward' of the remainder of the flag on all vehicles, be they plane, boat, tank or even space shuttle.

Deliberate "mistake": During the part of the movie where the USS Alabama is sinking deeper into the ocean a shot of the depth gauge was made showing the sub passing 1800 feet at a quick rate. About 20-30 seconds of shots were shown after this to further dramatize the peril of submarine and then the scene cut back to the depth gauge. This time however, the gauge was moving much slower and only shown the sub had sunk 15-20 more feet without any reason for the sudden slowdown in decent.

Continuity: As the Alabama dives for the first time you will notice that the periscope and antennae masts protruding from her conning tower keep switching from up to down, indicating that the film crew used footage from two different sub dives to achieve that sequence.

Factual error: After the first torpedo attack, it is explained to the XO that the last EAM was cut off when the radio buoy's cable was severed in the attack. An outside shot shows the rear of the sub traveling forward away from camera, with the frayed cable trailing from the top of the sub's hull at a slightly upward angle, and running beyond the rudder. In fact, what should really happen in the shot, is the cable will follow the surface of the hull because the flow of water around the sub would force it to. That would put the cable right into the propeller and cause all sorts of mayhem. This mistake could have been easily avoided by simply having had the cable cut shorter in the attack.

Factual error: Throughout the movie, everytime some type of casualty occurs or an alarm sounds, police type lights go off throughout the ship. Submarines don't have flashing lights or grated decks for that matter throughout the ship. The sound of the alarm is enough, since there are no deaf personnel on board a submarine.

Continuity: At 46:18, the captain says to make torpedo tubes 1 and 4 fully ready. When they're fired, they use torpedo tubes 2 and 4.

Factual error: Approximately 35 to 40 minutes into the movie, when Denzel is talking to the crew about upgrading to DEFCON 3, they say the last time was 32 1/2 years ago during the Cuban missile crisis of October 1962. The problem is that they both take place during October, meaning that the half year part is a mistake.

Factual error: The cook who was killed is well beyond the Navy's weight standards. He should never have been on the boat to begin with.

Factual error: Hunter gives the order to fire torpedoes 2 and 4. The external shot shows the torpedoes firing from opposite sides of the sub. On all US submarines, tubes 2 and 4 are on the same side.

Factual error: After removing him from command, Ramsey reviews Hunter's record, which says that Hunter was last stationed on the USS Alaska, SSBN-723. The USS Alaska is actually SSBN-732.

Plot hole: Throughout the movie an incoming EAM must go through an authentication process prior to it being considered valid. The crew failed to do this on the second EAM of the movie that set DEFCON 3.

Factual error: At one point a character sneaks through the bowels of the ship from one end to the other. This would be hard to do since he would have to pass through the lower level reactor compartment. Even if you could do this (there is no such passage on any nuclear sub) it would not be very healthy.

Factual error: Several times during the movie, we can see the radio operator with the screen contents "printed" on his face. As everyone knows, that just doesn't happen in real life.

Revealing: The hearing at the end of the movie is indicated as Navy Headquarters Pearl Harbor, but the interior scene is the council chambers at Burbank City Hall in California.

Continuity: When the fat sailor gets on the bus, Dougherty is adjusting his hat with his left hand. In the very next shot he has his right hand on his hat.

Other: Near the start of the movie, when Hackman initiates the Missile Drill, one of the seaman can be seen to be throwing a blanket over the fish tank by his bunk. How exactly did he manage to sneak it on there and, more to the point, how would the tank survive not spilling or smashing during heavy maneuvers/attack? Having said that the boat does seem to be a bit of a zoo, what with the Captain's dog and everything.