In 1943 and 1944, Adm. Blanchard was commanding officer of the submarine Albacore, which sank the Japanese aircraft carrier Taiho with a single torpedo on June 19, 1944, in the first phase of the Battle of the Philippine Sea, which also was known as "The Great Marianas Turkey Shoot."

Near the end of the war, Adm. Blanchard commanded a submarine division in the Pacific and in 1946 and 1947, he commanded a submarine squadron in San Diego. He was assigned to the Office of the Chief of Naval Operations in Washington from 1947 to 1950, and again from 1951 to 1953. During the first year of the Korean War he was operations and plans officer for the submarine commander of the Pacific fleet.

Survivors include his wife, Irma, of Rockville; two sons, Timothy, of Edgewater, Md., and George, of Laytonsville; three daughters, Pebble Prothero, Norma Beaubien and Terry Holdridge, all of Gaithersburg; one brother, Eugene Tanner of Rockville, and eight grandchildren.