Factual error: The boat used by Bullock and Defoe to get off the cruise ship is water jet powered. The boat is shown launching from a dry dock and into the water using its engine. This is impossible. The only way for a water jet powered boat to accelerate is to be in the water.
Other mistake: The bow thruster is activated to avoid colliding with the oil tanker. Since the thruster is never turned off, the cruise ship should have continued on traveling in circles. However, after scraping the oil tanker the cruise ship travels in a straight line into the island.
Continuity mistake: Just before the evacuation, the ship stops. When Merced runs to the computer in the bridge, the speed indicator shows 18.2 knots.
Continuity mistake: Alex is telling Annie to get on a lifeboat and is getting soaked. A minute later, when he enters the bridge, his suit is completely dry. (00:42:00)
Continuity mistake: When Alex rescues Drew, it is the middle of the night. There are a few consecutive events, then it is instantly daylight. But the events are all consecutive. There is no way the sun could rise that fast.
Continuity mistake: When Alex surfaces from under the ship, he chucks his mask off and it floats away. Once Geiger has forced Annie to drop Alex back into the water, he suddenly has the mask back. (01:21:00)
Answer: There is no logical reason for it and it is purely for cinematic theatrics. It's a movie myth that cars, boats, etc. immediately explode upon impact. In real life, explosions rarely happen that way.
raywest ★