 The U.S. Navy ended the Civil War with about fifty monitor @-@ type coastal ironclads ; by the 1870s most of these were laid up in reserve , leaving the USA virtually without an ironclad fleet . Another five large monitors were ordered in the 1870s . The limitations of the monitor type effectively prevented the USA from projecting power overseas , and until the 1890s the USA would have come off badly in a conflict with even Spain or the Latin American powers . The 1890s saw the beginning of what became the Great White Fleet , and it was the modern pre @-@ Dreadnoughts and armored cruisers built in the 1890s which defeated the Spanish fleet in the Spanish – American War of 1898 . This started a new era of naval warfare . 
