<P> Designed for speed, the clipper was built on sharp lines and carried a maximum of canvas and was the culmination of the intense rivalry between steam and canvas . It was intended primarily for long voyages, and was used especially for the California and Far Eastern trade . Given a fair breeze, a clipper ship could outdistance a steamship . It was not uncommon for a clipper to sail over 300 miles a day; the Flying Cloud (clipper) on a ninety - day run to San Francisco made 374 miles in one day . The Comet (clipper), on an eighty - day voyage from San Francisco to New York averaged 210 miles a day . It appeared that the American ship builder, before he relinquished his supremacy, was intent upon demonstrating to what heights of efficiency and speed a sailing ship could attain . </P> <P> The increased demand for shipping was the result of several factors . The discovery in 1848 of gold in California was a major cause along with the wars between Great Britain and China in 1840 - 42 and 1856 - 60 threw a part of the China trade into American hands . The revolutionary outbreaks of 1848 interrupted European trade, with a resultant benefit to Americans, while the Crimean War, which occupied many European boats in transporting troops and supplies, gave new openings to American ships . In addition the natural growth in population, wealth, and production necessitated increased shipping . </P> <P> The volume of mail between the United States and Europe increased substantially during this period, and the capacity of the sailboat to deliver this mail efficiently and within a reasonable time was uncertain . Following the precedent established by England and other maritime nations, the federal government began its aid to ocean shipping with the overseas mail service . On March 3, 1845, Congress authorized the Postmaster General to invite bids on contracts to carry mail between the United States and abroad . Regular subsidized service between New York and Bremen, Havre, Liverpool and Panama was established under the Act of 1845 . Subsidy payments averaged between $19,250 and $35,000 per round trip, and aggregated government expenditures to 1858 amounted to $14,400,000 . </P> <P> This development led to the formation of the U.S. Mail Steamship Company and the Pacific Mail Steamship Company . </P>

What proportion of the british merchant marine fleet was american built