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. (01:00:50)
Revealing mistake: After the XO orders all stop, we see a close-up of the ship's yoke being pulled back. The next wide shot shows the interior as the bow of the sub is rising, and just before this shot ends, note the console that the man with headphones is working at. A pair of crewmembers cross paths in the foreground, then the entire console wobbles, proving it isn't attached to the floor at all. (01:09:00)
Factual error: After the 2nd sub attack, while Hunter is in charge, a call is made from conn to maneuvering, to restore propulsion as soon as possible. It shows a young black dude answering back on the MC, having to yell over the noise of water spraying everywhere. This was laughable. Maneuvering is the control room for the nuclear power plant. It's all control panels and 4 technicians plus the EOOW, a nuclear-trained officer or senior enlisted, who would be answering back to conn. There wouldn't be any flooding going on there. (01:09:45)
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. (01:19:15)
Continuity mistake: After the submarine is hit by the first torpedo, 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.
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.
Character mistake: At the end of the movie, Ramsey and Hunter begin a conversation about Lippizaner horses. Ramsey says they are from Portugal, Hunter says they are from Spain. However, the Lippizaner horse's place of origin is believed to be in modern day Slovenia (though they are believed to have descended from Spain in the distant past). Lippizan is Slovenia's national symbol. Plus Lippizans are associated with the ‘Spanish Riding school' but the ‘Spanish Riding School' is situated in Vienna, Austria.
Factual error: Throughout the combat sequences with the Russian submarine, both the enemy sub and the missiles exchanged between the USS Alabama and the Russian sub are shown as blips on a radar scope. In real life, sonar displays look much different and resemble a "waterfall" pattern that trained sonar specialists can read.
Answer: In a war situation, the Captain is absolutely NOT allowed to try and contact anyone, lest it gives their position away, which is why he was unable to question or confirm the order.
GalahadFairlight
All respect to GalahadFairlight, but Hunter was not asking the Captain to 'contact' anyone, but rather to use all possible measures to receive the EAM. Active contact was not required, and in fact, going shallow would have been 100% necessary just to launch the missiles, at which point VLF reception would have been easily possible. No nuclear submarine captain would ever have been so stubborn, nor so dismissive of his own XO. Both of these were pure Hollywood inventions.