At 8:47 a.m. on 4 September 1941, while proceeding independently from Argentia to Reykjavik, Iceland, the Greer, under Lieutenant Commander L. H. Frost, was about 175 mi from Reykjavik when she was signaled by a British plane that a German submarine was 10 mi ahead in the Greer's path. This was the U-652, with which the Greer made sound contact at 9:20 a.m. At 10:32 a.m., having been informed by Frost that the Greer did not intend to attack, the British aircraft dropped 4 depth charges and departed to refuel. The Greer maintained contact, possibly for practice or possibly to mark the U-boat's location pending arrival of other British forces. At 12:48 p.m., probably identifying the Greer as one of the 50 similar destroyers recently transferred by the United States to Britain, the submarine fired a torpedo, prompting the Greer to drop 8 depth charges. At 1:00 p.m., the Greer evaded a second torpedo. The Americans lost sound contact and, although a British destroyer appeared, the Greer continued searching. She regained contact at 3:07 p.m. and dropped 11 more depth charges before finally disengaging at 6:40 p.m. On 11 September, President Franklin D. Roosevelt made this encounter the subject of a "fireside chat" on American radio, calling the German action "piracy" and issuing a "shoot-on-sight" order for U.S. ships on North Atlantic convoy duties as far as Iceland against German submarines. The Greer incident thus brought the United States and Germany substantially closer to war.
In October 1941, the Greer escorted the U.S. destroyer Kearny to Iceland after she had been torpedoed by U-568 and suffered the war's first American casualties at German hands. The Greer continued convoy and patrol duties in the Atlantic and Caribbean until February 1944 and provided training and plane guard service in home waters until June 1945. She was decommissioned in July 1945 and sold for scrap the following November. John A. Hutcheson Jr.
Abbazia, Patrick. Mr. Roosevelt's Navy: The Private War of the U.S. Atlantic Fleet, 1939–1942. Annapolis, MD: Naval Institute Press, 1975.; Blair, Clay. Hitler's U-Boat War. Vol. 1, The Hunters, 1939–1942. New York: Random House, 1996.; Morison, Samuel Eliot. History of United States Naval Operations in World War II. Vol. 5, The Struggle for Guadalcanal, August 1942–February 1943. Boston: Little, Brown, 1949.; Roscoe, Theodore. United States Destroyer Operations in World War II. Annapolis, MD: U.S. Naval Institute, 1953.
John A. Hutcheson Jr.