Surfboards used by ancient Hawaiians ranged from five to 15 feet long, measured five inches thick, and weighed up to 160 pounds. Many types of wood were used, most commonly koa or wiliwili which was particularly buoyant. Boards were shaped with a stone adz first, then smoothed with coral or rough stone abraders. The root of the ti plant or pounded kukui tree bark was used as a finishing stain, giving the board a durable, glossy, water resistant black surface. Alaia boards were approximately nine feet long, wide at the nose and tapered toward the stern. Alaia were good for skilled surfers riding rough waves. More maneuverable than olo, they were better for steep, fast-breaking surf and wave conditions along rugged coasts.