Another important invention by Chinese people, the keel framework (mostly wood) of Chinese ancient ships, has profoundly influenced the world's ship structure. The sharp-bottomed sea boats of the Song Dynasty (960-1279) usually featured a flat deck, curved sideboards (the sides of a ship), and a V-shaped form (in which, widthwise, the ship widens from bottom to top, hence the V-shape).

Under the sharp bottom, there was a keel framework running from the bow (ship's front) to the stern (ship's rear) to support the hull (ship's body) while also strengthening the whole ship. Such keel frameworks did not appear in European ships until the end of the 19th century, several hundred years later.

Author: Jessie