Character mistake: Characters refer to the Dallas and the Red October as "ships," but anyone stationed aboard a submarine would know to call it a "boat."
Continuity mistake: When Ryan is helo'ed to the Dallas it does not have a DSRV attached, but they use one later in the movie to board Red October.
Suggested correction: In the film more than 24 hours pass between the time Ryan gets on Dallas and when they show the DSRV attached to her. If you remember earlier in the movie it was stated that they could have the DSRV anywhere in the world in 24 hours. Therefore, one may assume that this time was used to get the DSRV to the Dallas.
Dallas was in the middle of tracking Red October and would have to have broken off the tracking (as it did anyway to pick up Ryan) in order for a sub tender to meet Dallas, place the DSRV on her, and then Dallas would have to hightail it back to find Red October. Plus getting the DSRV out to Dallas seems like a critical part of the story. While some scenes end up on the cutting room floor in every movie one has to wonder why there wasn't even a mention about having to surface for the DSRV.
Dallas didn't need to track the Red October anymore because the extraction point was already arranged, so it was very plausible the Dallas could get access to the DSRV.
Other mistake: When the sub is ordered to turn right, Ramius is seated facing forward and tightens his seat belt. When the sub makes a tight right turn, his coffee cup slides the wrong way. (01:00:01)
Visible crew/equipment: On the Dallas, the two men are listening to sonar and get a fax that the Soviet sub is a new type. The camera moves in on the man (Jones) on the left seat and its shadow is very visible on his seat.
Continuity mistake: When Sally is saying that Stanley is keeping her awake, her grip on the bear's ear is changing between constant shots. (00:04:40)
Continuity mistake: When chasing the KGB agent, Ryan climbs up a ladder empty handed, but when he rolls over on the walkway he has a gun in his hand.
Revealing mistake: Near the end, when Ryan and Ramius are talking, right before Ryan says "welcome to the New World", Ryan is facing Ramius and his thick hair should be blocking the hill in the distance behind him, but his hair is translucent and the hill is visible through his hair. (02:06:00)
