A boat hull is the main body of a boat that sits in the water. It is designed to provide stability and buoyancy, allowing the boat to float and move efficiently. Hulls can be made from various materials, including fiberglass, wood, and aluminum, each offering different advantages in terms of weight, durability, and cost. There are different types of hull shapes, such as displacement hulls and planing hulls. Displacement hulls are designed to push water aside and are typically used for slower boats, while planing hulls rise above the water at higher speeds, allowing for faster travel. The choice of hull shape affects a boat's performance and handling.