Poseidon (2006) - 6 mistakes

Continuity: During the capsizing in the disco, a light rigging falls and knocks some people over. There is a woman in a black top and pink skirt - she falls over twice between the two shots.

Plot hole: When the ship has turned on its side for the brief moment, it cuts to inside the ship where a hallway explodes, causing the ship to submerge. The only problem is the people are standing on the ceiling, but if the ship's on its side, they'd be on the wall, not ceiling.

Audio problem: The source music in the ballroom does not match the Poseidon orchestra's motions.

Factual error: In the scene where everyone is in the first ballast tank and the water is turned on, there is air inside the ballast. As the water level rises, the air will become more and more compressed at the top until eventually there should be a thin cushion of air on the top with sufficient pressure to resist any additional flooding. Now I know nothing about the construction of ballast tanks, so there may be a vent on the top to let air out as it fills normally. If there is such a vent, it would now be in the bottom since the ship capsized. So when the characters rise up to the top, that is actually the bottom of the tank with no holes/vents for the air to escape.

Factual error: When the ballast tank valves open, they open by dropping down, which would be impossible with the pressure of the water pressing against it. Regardless of the domino effect of the water flowing, it's tremendous pressure.

Factual error: After the first ballast tank is flooded, the others are shown filling during the rest of the movie. But since the ship is upside down and the valves therefore at the top of the tank, all of the water is below the valve, and couldn't possibly flow through it to the next tank.