A bulb keel is a type of keel used in sailing vessels, characterized by a bulbous shape at the bottom. This design helps to lower the center of gravity, improving stability and reducing the risk of capsizing. The bulb also increases the surface area in contact with the water, enhancing the boat's ability to resist sideways movement, known as leeway. Bulb keels are commonly found on modern racing yachts and cruising sailboats. They are often made from heavy materials like lead or iron, which adds weight to the keel while keeping the hull lightweight. This combination allows for better performance and maneuverability on the water.