Harold Gardiner Bowen Sr. (6 November 1883 – 1 August 1965) was a United States Navy Vice admiral, former head of the Office of Naval Research and a mechanical engineer.

He received his commission as ensign upon passing his final examinations as a midshipman in the spring of 1907, after which he was assigned to Kansas during the first leg of the Great White Fleet.

Hopkins suffered a boiler accident and two sailors were killed, but Bowen was away from the ship that day taking a promotions exam.

[8] Bowen spent three years ashore ending July 1922, part of it as a shop superintendent and later as Engineer officer of the Mare Island Navy Yard.

[11] While there Bowen was a champion for research and development (R&D) of high pressure, high temperature steam propulsion,[4] which employed pressures at 650 PSI and temperatures of 800 F.[12] This technology was said radically to have changed maritime steam turbine operation, increasing the speed and range of Navy ships in World War II.

According to Amato, in "Pushing the Horizon", a history of the Naval Research Laboratory, Bowen's leadership of NRL was mixed.

His and the Navy's first corporate seizure of World War II was Federal Shipbuilding and Drydock Company in Kearny, New Jersey.

The large shipyard near New York City had shut down due to a strike for the better part of August 1941 with no work being done on $493 million ($10.2 billion today) in defense contracts.