Visible crew/equipment: In the scene where Ryan is being flown out to the Dallas, the door crew member looks out and says, "Yo, got a sub about 2 miles out." If you look closely in his goggles, you can see the reflection of the crew. (01:45:30)
Visible crew/equipment: When Jones the Sonar operator detects the Red October for the final time via his headphones, he is talking to someone next to him. The whole time he is doing this, a microphone boom is constantly bobbing into view from above his head.
Factual error: When the USS Dallas submerges to attack the Red October, they rig for battle stations as well as rig for red. On a submarine, rig for red is only for periscope depth operations at night, to allow control room watchstanders eyes to adjust to the darkness topside. No other area on the boat rigs for red. Throughout the movie the lights darken along with battle stations. No naval ship would reduce visibility on purpose in a heightened state. (01:31:00)
Trivia: Paramount Studios essentially rented a US submarine to be in the movie. The USS Houston (SSN 713) played the USS Dallas and the surface scenes were filmed off of Long Beach, CA and Port Angelas, WA. Two crewmembers off the Houston were actually given very small speaking parts in the movie.