Continuity mistake: When the alarm sounds in the boiler rooms, the officer shouts "Shut all the dampers." We see all of the firemen shut all the loading doors to the furnaces. But a few clips later, when water pours in, the water flows past open furnace doors. (01:35:00 - 01:37:20)
Factual error: When the ship hits the iceberg and the plates of the hull start to buckle and break apart, it shows a scene on the inside of the ship showing the walls buckling in, along those walls you can see vertical pipes that appear to made of PVC, similar to the pipes used for sewage drains in modern building structure. I don't think PVC was around in 1912, the pipes would have been made of cast iron or lead and they would not have been white. (01:37:00)
Continuity mistake: We see Mr Andrew walking through the 1st class cabins just after hitting the iceberg. He has 4 blueprint rolls under his arms. We then see him out on deck while discussing the situation with a few other men and the rolls have gone. As he gets to the office with Captain Smith he has the rolls again. (01:39:20)
Continuity mistake: The way the necklace is held after it is found in Jack's pocket changes instantly. In one shot the steward is gripping the chain. In the next, the chain is draped over his fingers. (01:41:10)
Revealing mistake: When the cop find Rose's necklace in the coat, Jack says "he put it in my pocket" and Cal tells him to shut up. Right then, he turns his head and the glue of his wig is noticeable around his temple. (01:41:30)
Continuity mistake: After handcuffing Jack, Lovejoy says the initials on his coat and Jack turns to Rose. A frame later, from a different angle, he is looking away. (01:41:35)
Continuity mistake: When the diamond is found in Jack's pocket the way Rose's hair is messed up is different in every single shot. (01:41:45)
Audio problem: When the steward is getting Rose and Cal's life jackets from the closet he says about top coats and hats, However his mouth stops moving after the word coats. (01:44:00)
Continuity mistake: When the Captain tells the morse operator to make an emergency call, the position of the papers and pencils in front of him move around between shots. (01:44:50)
Factual error: Professional Radio Operators hold the key used for Morse code between their thumb and two fingers - they don't tap it, as was shown. Tapping would produce a harsh voice in Morse code. (01:45:25)
Factual error: The radio system in use at that time was based on spark transmission and we should never have heard a nice clean transmission of Morse code SOS or CQD beeps. (01:45:25)
Audio problem: When Rose is talking to Thomas Andrews, telling him to tell her the truth about what has happened, listen to the voices in the background. At one point in the scene you can hear someone saying "Yes madam, please put it on immediately", then someone laughs. Right at the end of the scene, the same line can be heard in exactly the same tone of voice, followed by the laugh - it's obviously a loop. Although some tracks in the mix of the soundtrack do not loop at that moment, the track with the mentioned sentence does. (01:47:30)
Factual error: When Jack is handcuffed to the pipe below decks, the elbow joint is a modern welded joint, not a bolted flange joint as in the rest of the ship. I'm sure this was done to allow Jack to move about with greater ease as the water level rose. (01:47:50)
Factual error: Jack (Leonardo DiCaprio) was handcuffed with old English Hiatt's Darby Handcuffs (type 104). This is historically correct. But the key for these handcuffs identifies them as modern reproductions, because it had a flat top and was "checkered". The old keys had an oval and smooth (only marked with "Hiatt" and a number) top. The handcuffs used in the film were not from 1912. (01:47:50)
Factual error: The Master-at-Arms office, where Jack is handcuffed, was in actuality an inside cabin and had no portholes at all. (01:51:10)
Continuity mistake: When Rose Cal and Rose's mother are standing on deck, Rose says "oh mother, shut up ", before the face shot of her mother you can see she is already looking at Rose in the previous shot, then she whips her head around again to look at Rose. (01:52:10)
Continuity mistake: When Jack is cuffed and has just looked out of the window, we have just seen his window is about 10 feet underwater, but when we see him banging his handcuffs, we can see the top of the waterline in the window. (01:52:40)
Continuity mistake: After Rose refuses to get in the lifeboats there's a shot of handcuffed Jack crying for help. A frame later his fringe has swapped from combed to parted. (01:52:40)
Continuity mistake: Just after Rose leaves Cal, we get an underwater shot panning down on Jack, showing that the window he's standing next to is fully submerged. However, interior shots after that show air around the upper edge of it. It's not trapped air: it's constantly bouncing around, in a wave-like pattern. (01:53:10)
Continuity mistake: When cuffed Jack is screaming for help, you can see the water level in the porthole in the background although the room in which he is cuffed, has already been shown to be completely under water. (01:53:40)
Suggested correction: I checked the plans. It's an outside cabin.
It's an inside cabin per the deck plans. Https://www.encyclopedia-titanica.org/titanic-deckplans/e-deck.html.