Spanish–American War

On a later voyage following the outbreak of the Spanish–American War, St. Louis was chartered for Naval service while at Southampton and returned to New York on 22 April 1898. Armed with four 5-inch rapid fire guns and eight 6-pounders, she was commissioned as an auxiliary cruiser in the United States Navy on 24 April, Capt. Caspar F. Goodrich in command. St. Louis, crewed by 27 officers and 350 men, departed on 30 April for the Caribbean.

St. Louis was specially outfitted with heavy drag lines in order to destroy undersea cable communications in the West Indies and to the mainland of South America. On 13 May, the ship severed a cable between St. Thomas and San Juan, and on 18 May engaged in gunfire with the Morro Castle batteries at Santiago de Cuba while cutting another cable. When Admiral Pascual Cervera's fleet sailed into Santiago Harbor, the Spanish warships found themselves cut off from direct communications with Spain.

St. Louis next severed the cable between Guantanamo Bay and Haiti; then cut the cable off Cienfuegos to isolate Cuba from outside communications. She joined in the bombardment of fortifications at Caimanera in Guantanamo Bay on 3 June; captured a Spanish merchant ship on the 10th; intercepted two British ships bound for Cuba - the Twickenham on 10 June and Wary on 1 July; and was present at the Battle of Santiago de Cuba on 3 July when the Spanish Fleet was destroyed while trying to force its way to sea.

St. Louis received many prisoners of war, including Admiral Cervera, for internment in the United States and landed them at Portsmouth, N.H., on 11 July. She steamed south from Norfolk on the 28th to cruise among ports of Puerto Rico and Cuba until 10 August; then sailed for New York where she arrived on the 14th. She shifted to Philadelphia on 24 August to enter the Cramp shipyard for preparation for return to her owners. St. Louis was decommissioned on 2 September and was turned over to Mr. J. Parker, a representative of the American Lines.

World War I

For many years, SS St. Louis was prominent as a passenger liner between New York and Liverpool. For example, in June 1906, the newly married Alice Roosevelt Longworth sailed on the ship for her first trip to Europe.^[1] On 17 March 1917, she was provided with an armed guard of 26 sailors and equipped with three 6-inch guns to defend against enemy attack on her New York-to-Liverpool service route. On 30 May, while proceeding up the Irish Sea and skirting the coast of England, she responded rapidly to the orders, "Hard Starboard," at the sighting of a periscope, and succeeded in dodging a torpedo while apparently striking the submarine which fired it. Later dry-dock examination revealed that 18 feet of her keel rubbing strake had been torn away. On 25 July, her gunners exchanged fire with a surfaced U-boat, some three miles away, and sighted many near misses.

351st Field Artillery troops on the deck of the Louisville, Feb. 17, 1919

On 17 April 1918, St. Louis was delivered to the Navy at New York to be wholly manned and operated by the Navy as a troop transport. She was renamed Louisville (SP-1644) to avoid confusion with the heavy cruiser St. Louis. Louisville was commissioned on 24 April.

Louisville first put to sea on 12 October bound for Portland and Southampton, England, and returned to New York on 7 January 1919. From then until 19 August of that year, she made six voyages from New York to Liverpool or to Brest, France, to return American soldiers from the Great War. On 20 August, she shifted to Norfolk and was decommissioned there on 9 September 1919. She was returned to her owner on the 11th and resumed her original name, St. Louis.