A bulb keel is a type of keel used in sailing vessels, designed to improve stability and performance. It features a bulbous shape at the bottom, which lowers the center of gravity and enhances the boat's ability to resist tipping. This design allows for better handling in various wind and water conditions. Bulb keels are commonly found on racing yachts and cruising sailboats, as they provide a balance between weight and hydrodynamic efficiency. By increasing the surface area underwater, they also help reduce leeway, allowing the vessel to sail more effectively against the wind.