Steel Ships: The Density Trick

Steel is nearly eight times denser than water. A solid steel ball sinks immediately. So how does a 100,000-ton aircraft carrier float?

The hull is a hollow shell. The ship is not solid steel — it is a steel-shaped air container. When you calculate the average density of the entire ship (steel walls plus all the air inside), it is far less than water.

The ship sinks until it displaces a volume of water weighing exactly as much as the entire vessel. For a carrier, that means the hull sits deep. Load more cargo and the ship sits lower. Remove cargo and it rises.