Why do large heavy ships float?

It is this upward water pressure pushing on the bottom of the boat that is causing the boat to float. Each square inch (or square centimeter) of the boat that is underwater has water pressure pushing it upward, and this combined pressure floats the boat. For more information, check out the links on the next page. read more

First of all, an object floats if its OVERALL density is less than the density of the fluid in which it is placed.(it can be shown) The metal ship, due to the large pockets of air inside the ship, has a lower density than water. The piece of metal has a higher density than water. Thus, the piece of metal sinks while the metal ship floats. read more

Clever ship design allows very large, very heavy ships to float, simply by displacing an amount of water of greater weight than the ship itself. Once the ship's hull has been designed to take this into account, adding more weight, for example cargo, increases the gravity force acting on it which causes it to dip lower into the water, displacing more water and increasing the strength of the buoyancy force. read more