United States TENTH Fleet

From Anti-submarine Warfare to Cyberspace

From the beginning of World War II, the Germans waged an incessant U-Boat war in the Atlantic against Allied merchant vessels. Upon its entry into the war in December 1941, the U.S. provided an even greater wealth of targets for the German U-Boats.

Upon its establishment, TENTH Fleet became a clearing house for everything involving Anti-submarine Warfare (ASW). All of the Allies worked together with TENTH Fleet for a unity of effort. TENTH Fleet had unrestricted access to the Admiralty’s U-Boat tracking room and its various ASW research and intelligence agencies.

Coordinated ASW began in the United States on February 6, 1942, with the formation of a small group within COMINCH staff, ultimately designated F-25, that was dedicated to ASW. The following day, a separate unit was established under CINCLANTFLT in Boston.

On March 1, 1943, the Allies met in Washington to discuss convoy operations in the Atlantic. At this conference, they agreed to divide up responsibility for the Atlantic between Canada, Britain, and the United States.

In April of 1943, Fleet Admiral (FADM) Ernest King began the consolidation of his staff that would result in the establishment of TENTH Fleet. He appointed Rear Admiral (RADM) Francis “Frog” Low as his Deputy Chief of Staff for ASW and re-designated F-25 as F-36, the Anti-submarine Measures Division. Shortly thereafter, Admiral King sent a memo to the Joint Chiefs of Staff titled “Anti-submarine Operations.” This memo defined the operational characteristics of a central organization with access to all intelligence about German U-Boats and the authority to direct Navy ships to prosecute them. One month later, on 20 May 1943, U.S. TENTH Fleet was formally established.

Located at COMINCH HQ in D.C., TENTH Fleet was composed of five primary sections: Operations, Anti-submarine Measures, Convoy and Routing, the Civilian Scientific Council, and the Air Anti-submarine Development Unit. Additionally, the ASW Operational Research Group (ASWORG) provided regular reports of new technologies and tactics to TENTH Fleet.

Originally slated to be headed up by another Admiral, TENTH Fleet ultimately remained directly under FADM King, located at the COMINCH Headquarters building in Washington. RADM Low ran the day-to-day operations, with FADM King’s authority behind him allowing him to direct ships as necessary. RADM Low successfully ran TENTH Fleet until he was promoted and relieved by RADM Allan R. McCann, who continued to run the organization until its disestablishment.

The focal point for TENTH Fleet, the Operations section headed by Captain Haines, was formed from the original F-21. F-21 was the Atlantic section of COMINCH’s Combat Intelligence Division, ably led by Commander Kenneth Knowles, whose intelligence was instrumental in TENTH Fleet’s prosecution of the U-Boat threat. This section utilized information from all the other sections combined with all source intelligence to guide the operations of the various hunter-killer groups. Sources included intercepted German communications provided by OP-20-G, the precursor organization to Naval Security Group, and interrogations of captured U-Boat crews provided by OP- 16-Z, Naval Intelligence’s Special Activities Branch.

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