His next venture was building one of the first screw steamships to reach South America from England. His small ship Flecha was not a business success, however. In 1849 he joined the California Gold Rush. By 1850 he had lost his fortune, and hired as a common sailor bound for China. He got as far as Honolulu in the Hawaiian Islands where Robert Cheshire Janion hired him into the firm of Starkey, Janion & Company. Green became a partner and the company was known as Janion, Green & Company. By 1851 he founded and became first president of a social club for British residents he called "The Mess". It was later renamed The Pacific Club.
