An alaia (pronounced: uh-lie-yuh) is a thin, round-nosed, square-tailed surfboard ridden in pre-20th century Hawaii. The boards were between 7 and 12 ft (2.1 and 3.7 m) long, weighed up to 100 lb (45 kg), and were generally made from the wood of Acacia koa. They are distinct from modern surfboards in that they have no ventral fins, and instead rely on the sharpness of the edges to hold the board in the face of the wave.