Built by William Webb at New York for Griswold & Co. of the same port, Challenge was intended to be the fastest clipper afloat and her dimensions show that she was larger than any clipper hitherto constructed. Undoubtedly Webb's finest-lined creation, she was registered at 2,006 tons and measured 230 feet in length with a 43 foot beam. Despite the care lavished on her construction, she proved 'overhatted' and this probably accounted for her rather disappointing maiden voyage to San Francisco of 108 days in 1851. Once this was remedied, she ran across the Pacific from Japan to San Francisco in 18 days, still a record, and thereafer performed well until sold in Hong Kong in 1861. Renamed Golden City, she was resold again five years later and subsequently wrecked off the French coast in 1876.
Empress of the Seas was built by Donald McKay at East Boston and launched on 14th January 1853. Registered at 2,197 tons (American), she measured 240 feet in length with a 43 foot beam, and carried a magnificent female figurehead holding a globe and the sceptre of the seas. Sold to William Wilson & Son of Baltimore for $125,000 whilst still on the stocks, she began her career on the California run making her maiden passage out in 121 days. Transferred off the San Francisco route in 1858, she eventually began sailings from England to Australia and in 1861 made the run from Liverpool to Melbourne in a remarkably fast 66 days. On 19th December the same year, she caught fire at Port Phillip and became a total loss.