When Cliff is saving his daughter, he uses a board to help her across. When first shown, it looks brand new, and when they are going across it, it's clearly a different, more rotten looking one. It changes from scene to scene.
Just before the little girl crawls over to the plank, an aerial shot of the hole shows no plank. As she crawls to the plank, the plank is visible in the next aerial shot.
In several sequences on the bridge, some of the windows are alternately closed and open in different shots within the same scene.
There are many sequences where the skies change from cloudy and overcast to bright sunshine in different shots within the same scene.
In the final shots of the ship sinking, the nearby coastline can be seen reflected in its outside windows.
When the first explosion occurs in the dining room, the piano player can be seen clearly, without any arms or legs; hence. this is a dummy.
In the final scenes of the ship sinking, as the characters jump into the water, there is an inrush of sea water onto the deck. The ship's bulkhead clearly bends over with the weight of this water as this is obviously a wooden film set and not the real ship they jump from.
Although the ship is supposed to be either British or American, most of the playing cards in the engine room are in French. Additionally, many pressure gauges read zero, indicating that only two boilers were lit, and at reduced pressure. This probably was to supply service steam to alternators for the ship's power.
When the ship's smokestack cracks and falls onto the bridge, it is obviously being pulled forward, because it would be impossible for the entire thing to balance so precariously on its own.
In the final scene of the ship sinking as the characters leave it, a crew member in full scuba gear can be seen.
(at around 2 mins) As the Captain and his two officers leave the dining room to check on the fire, the shadows of the boom microphones can be seen against a wall behind them.
When the Captain finally gives the order to send an SOS, the radio operator says the wrong name of the ship twice.