Robert Ernst Barnhart was born in New York, New York, on November 3, 1919, son of Ernst G. and Elna C. (Erikson) Barnhart. He attended Webb Institute of Naval Architecture, Glen Cove, Long Island, New York, from which he received the degree of Bachelor of Science in Naval Architecture and Marine Engineering in 1941. On April 2, 1941 he was commissioned Ensign in the US Naval Reserve and subsequently advanced in rank to that of Captain, to date from July 1, 1960, having transferred to the Regular Navy on July 12, 1946.
Ordered into active naval service, he served from May 1941 to September 1943 as Ship Superintendent and Docking Officer at the Pearl Harbor (Territory of Hawaii) Naval Shipyard. He was in that assignment when the Japanese attacked the Naval Base there on December 7, 1941 and was subsequently engaged in the repair of battle damage to ships of the Pacific Fleet. He next had similar duty at the New York (New York) Naval Shipyard, where he was Ship Superintendent for the new construction of the carriers Bennington and Kearsarge. In Jun 1946 he reported for instruction at the Massachusetts Institute of Technology at Cambridge, from which he received the degree of Master of Science in July 1948. While there he participated in a Caribbean cruise during the period June to September 1947 in the USS Albany.
He next served as Damage Control Assistant on board the USS Leyte and in September 1949 was detached for duty first as Industrial Engineering Officer and then as Assistant Design Superintendent at the Portsmouth (New Hampshire) Naval Shipyard. There he was engaged in submarine design and construction. Transferred in May 1952 to the Charleston (South Carolina) Naval Shipyard, he was Assistant Planning and Estimating Superintendent for Submarines and Assistant Repair Superintendent. From July 1955 to July 1957 he headed the Technical Section, Office of Naval Intelligence, Officer of the Chief of Naval Operations, Navy Department, Washington, DC. As such he was responsible for foreign scientific and technical development of naval interest. He next reported as Hull Inspector on the Board of Inspection and Survey, Washington, DC. In that capacity, he was concerned with material inspection and acceptance trials for new naval ships. In September 1958 he became Head of the Hull Structural Fittings and Preservation Branch, Bureau of Ships, Navy Department, where he was in charge of the development of specifications for hull equipment of the US Navy.
He served successively as Repair Superintendent, Planning Officer and Production Officer at the US Naval Ship Repair Facility, Yokosuka, Japan, from July 1960 to May 1963, when he assumed command.
In August 1963 he returned to the Bureau of Ships, to serve first as Deputy Inspector General then as Director of the Industrial Engineering Division until July 1965, when he became Executive Director for Shipyard Management. He continued to serve in that capacity after the Bureau of Ships was redesignated Naval Ship Systems Command, upon the reorganization of the Navy Department, effective May 1, 1966. In December 1967 he assumed command of the Pearl Harbor (Hawaii) Naval Shipyard.
Captain Barnhart has the American Defense Service Medal; American Campaign Medal; Asiatic-Pacific Campaign Medal; World War II Victory Medal; Navy Occupation Service Medal, Europe Clasp; and the National Defense Service Medal with bronze star.
He is a member of the American Society of Naval Engineers and Sigma Xi (MIT Chapter). He has served as a Director and President of the Navy Federal Credit Union.