Corrected entry: As second officer Lightoller prepares to go off-watch on that ill-fated night, he is referred to as "Lieutenant". The rankings of the officers on a commercial vessel are, captain, first (or chief) officer, second officer, etc.
Corrected entry: In the film, the crew are unable to contact the Californian (the ship on the horizon) because it doesn't have radio. In fact, the Californian did have radio, it just happened to have been turned off.
Correction: You do see the wireless on the Californian during this film, a few times - mostly at the beginning when the Titanic is sending private messages & the Californian are listening in, and later on when their trainee wireless operator switches on their box and hears the first of the Titanic's distress calls, but doesn't understand them & switches it back off.
Corrected entry: When a lifeboat is floating upside down, and people are trying to climb onto it, it is not bobbing from side to side at all, as if it was fixed to the bottom of the water.
Correction: The water in the area at the time was a dead calm - it is believed that one of the reasons the iceberg was not spotted until too late was that no waves were breaking against it. It is therefore quite possible that the lifeboat would not bob up and down.
Corrected entry: It has been established that the ocean was unusually calm the night of the collision, one of the reasons the iceberg was not seen earlier, yet the scenes of the Carpathia show her ploughing through some serious swells.
Correction: The Carpathia was sailing from New York City to Fiume, Austria-Hungary (now Rijeka, Croatia), on the night of the disaster, and thus was coming from the opposite direction, where conditions were different.
Corrected entry: As the ship is about to take its final plunge, a small group of Irish steerage passengers is seen desperately clambering up the rising deck towards the stern. They include the young man seen singing in the third class saloon earlier in the film. Shortly afterwards they are shown again, still on board and awaiting the inevitable. One minute later they have all been miraculously transferred to a lifeboat, in time to witness the ship's passing. As the "Titanic" slips beneath the sea, the aforesaid singer begins reciting the Lord's Prayer. (01:40:00)
Correction: The group of Irish steerage passengers are not "miraculously transferred to a lifeboat, in time to witness the ship's passing". The group is still on the stern as it starts to take its final plunge, and they begin to say the lords prayer, while many other passengers on the stern begin to pray in various languages. Later several of the the aforesaid Irish steerage passengers are seen swimming up to the overturned Collapsible B after the Titanic has foundered.
Correction: He's addressed as Lieutenant by a passenger - that would make it a character mistake. It's quite likely that a passenger may not understand merchant ranks.