The word "yacht" ("hunter"; Dutch "jacht";[1] German "jagd",[2] literally meaning "to hunt") was originally applied to small, fast and agile naval vessels suited to piracy and to employment by navies and coast guards against smugglers and pirates.
Before the outbreak of war in Europe, there had been much discussion in the United Kingdom of a wartime role for privately owned motor and steam yachts and smaller power boats.
[6] The British armed yacht HMS Lorna destroyed the German U-boat SM UB-74 with depth charges off Portland Bill in May 1918.
[8] On the entry of the United States into the war in April 1917, a large number of motor yachts were acquired by the US Navy and Coast Guard.
[9] During World War II, the US navy commandeered small vessels, including private yachts, and requisitioned them to patrol US coastal waters and the Gulf of Mexico against German U-boats.
[10] Some of these boats were armed with a .50 caliber machine gun in the bow and four depth charges on racks in the stern, although actually attacking a U-boat was probably suicidal.
The lopsided battle would have conceivably ended with the U-boat using its deck guns to blow up the patrol yacht (since scoring a hit with a torpedo was improbable).