By these arguments, Brunel in December 1840 was able to persuade the Great Western Steamship Company to adopt screw propulsion for the Great Britain, thus making her the world's first screw-propelled transatlantic steamer. Unfortunately, instead of using Smith's proven design, Brunel later decided to install a six-bladed "windmill" propeller designed by himself. Brunel's design was to prove a costly failure for the company.[24]