bulb keel

A bulb keel is a submerged, bulb-shaped weight attached to the bottom of a sailboat's keel. Its primary function is to lower the boat's center of gravity, providing stability and preventing it from capsizing in strong winds or rough seas. The bulb design enhances ballast efficiency by adding weight without significantly increasing the overall keel size, which helps the boat stay upright and improves its handling and performance under sail.