Retired Navy Rear Adm. James A. McNally, 74, an engineer and electronics specialist, died Saturday at his home in Potomac.

At the time of his retirement in 1956, he was chief engineer of the Atlantic Reserve Fleet, dividing his time on duty in Washington and New York. In addition to his home in Potomac, he maintained a home in Montclair, N.J.

Born in Boston, Adm. McNally graduated from the U.S. Naval Academy at Annapolis in 1925. He later earned a master's degree in electronics from Columbia University.

He was on shore duty at Pearl Habor when the Japanese attacked in 1941 and became salvage planning officer in charge of raising and repairing ships sunk or damaged in that attack.

Later in World War II, Adm. McNally served as chief engineer of the carries, the U.S.S. Yorktown, and second in command of the battleship, the U.S.S. Massachusetts, participating in many major battles in the Pacific.

After the war, he served here as manager of the Naval Research Laboratory and director of applied science in the Bureau of Ships.

Following his retirement, Adm. McNally was associated with the Bludworth Marine Division of the Kearfoot Co. and was a project representative for RCA.

He was a member of the Photographic Society of America, receiving its highest honors for his photography. He belonged to the Army and Navy Club here.

He is survived by his wife, Marjorie P. McNally, of the home; two daughters, Patronienne M. Atkins, of Potomac, and Eileen Carter, of Haddonfield, N.J., and five grandchildren.