Ann McKim was one of the first true clipper ships. The opening of new Treaty ports in the East in the early 1840s eased an access of the US merchants to China, which demanded the ships that could move cargo faster than then-traditional slow-moving, high-capacity merchant ships. The Ann McKim was one of the ships that had answered the demand in the early years and sailed between New York and China in 1840–1842, until newer and faster cargo-carriers, such as the nearly 600-ton clipper Houqua, the 598-ton China packet Helena, Witch of the Wave, and Rainbow, with the last two built expressly to outperform the Ann McKim started dominating the shipping world of the US-China trade and the Ann McKim was shifted back to the South American trade routes.