Shamrock was a racing yacht built in 1898 that was the unsuccessful Irish challenger for the 10th Americas Cup in 1899 against the United States defender, Columbia. Shamrock was designed by third-generation Scottish boatbuilder, William Fife III, and built in 1898 by J. Thorneycroft & Co., at Church Wharf, Chiswick, for owner Sir Thomas Lipton of the Royal Ulster Yacht Club. She was skippered by Captain Archibald “Archie” Hogarth. She sailed to New York for the Americas Cup race in the summer of 1899. The Cup defender Columbia beat Shamrock in all three races. She returned to Britain in the autumn of 1899 and was subsequently refitted by Lipton and used as a “trial horse” to test the later challengers, Shamrock II, Shamrock III, and Shamrock IV.