Factual error: No ship has ever been - or ever will be built without having emergency fuel shutoff devices that can be manually operated.
Suggested correction: Yes, but the fuel shut off valves would have been located in the engine room. The doors to the engine room had been locked by the bad guy.
Not only in the engine room but also at the bridge and most probably the steering gear room as well.
Other mistake: Throughout the entire film, Alex manages to keep the engagement ring in his pocket after everything that happened. (01:51:50)
Suggested correction: People manage to keep things in their pockets all the time after enduring a lot of different activities. This is in no way a mistake whatsoever.
Continuity mistake: When the cruise liner is heading towards the oil tanker, her speed is 17kts. When the oil taker is monitoring the cruise ship, the speed it's doing is 14kts. Alex's attempt to slow the cruise ship down failed so that won't explain the difference. (01:18:00 - 01:21:00)
Suggested correction: This is incorrect due to how ships record speed. In fact it is probably the most factual thing in the entire film! The Seaborn Legend records its speed using GPS like every other ship, but it will also take into account current speed and direction (speed and direction the water is moving at) Any other ships would see the same GPS data which would show the speed lower than what it actually is. In the nautical word, this is known as "Speed Over Water VS Speed Over Ground"
Continuity mistake: When Alex realises Drew is in the ballast tanks by looking at the monitor, he says "f**k" before anyone can be seen on the screen. (00:59:20)
Suggested correction: I think your film may have been out of sync slightly as this doesn't happen on my copy?
