What does the keel of a vessel refer to?

The keel of a vessel serves multiple important functions that contribute to the overall performance and stability of the boat. It refers to the main centerline of the vessel, which runs from the bow (front) to the stern (back), providing structural integrity and helping to maintain the vessel's shape. Additionally, the keel often extends downward into the water, which increases the boat's stability by lowering its center of gravity, thus making it less likely to tip or roll over in rough conditions.

This combination of characteristics—being central to the vessel's design and enhancing stability—means that both aspects, the main centerline and the extension that increases stability, are integral to the function of the keel. This is why the most comprehensive answer includes both attributes, highlighting the keel's dual role in boat construction and performance.