A boat hull is the main body of a boat that sits in the water. It is designed to provide buoyancy, stability, and protection for the boat's interior. The shape of the hull affects how the boat moves through the water, influencing speed and handling. Common hull types include displacement hulls, which move through the water, and planing hulls, which rise above the water at higher speeds. The materials used for constructing a hull can vary, including fiberglass, wood, and aluminum. Each material has its own advantages and disadvantages, affecting durability, weight, and maintenance. Proper hull design is essential for ensuring safety and performance on the water.