Critical to America’s ability to break Enigma and collect special intelligence related to the Kriegsmarine were specific organizations in place at the time.  One of those key organizations was U.S. TENTH Fleet.
The U.S. TENTH Fleet was originally established on May 20, 1943 following years of heavy merchant losses to German U-boats in the Battle of the Atlantic.  Similar to its modern day namesake, the TENTH Fleet of World War II did not own any ships nor was it aligned to a particular region as are today’s numbered fleets.  Rather, it was specifically formed to better coordinate and prosecute anti-submarine warfare against the German U-boat threat.   Its commander was the sitting Commander in Chief (COMINCH) and Chief of Naval Operations (CNO), Fleet Admiral Ernest J. King.  Though TENTH Fleet did not own any ships, it had the authority to direct their efforts – and direct them it did.

*Below is taken, in part, directly from the FCC/C10F public website.

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.

Anti-Submarine Warfare

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.

Rapidly proving its worth, TENTH Fleet demonstrated immediate success. On May 22, 1943, just two days after establishment, TENTH Fleet provided intelligence to the hunter-killer group led by USS BOGUE (CVE-9) and VC-9. This intelligence resulted in the sinking of U-569, which was the first U-Boat sunk by an American carrier-escort, the first of many for USS BOGUE, and the first associated with the intelligence provided by TENTH Fleet.

While not the only organization in the war combating the U-Boat, the efforts of TENTH Fleet certainly helped bring about the end of the U-Boat threat. Prior to the establishment of TENTH Fleet, the Allies averaged barely more than four U-Boats sunk per month. During the month TENTH Fleet was established, the Allies sank 41, and averaged more than 23 per month thereafter. Oberleutnant zur See Herbert A. Werner, a former U-Boat commander and one of the few to survive the war, described it succinctly when he said, “The Allied counter-offensive permanently reversed the tide of battle. Almost overnight, the hunters had become the hunted, and through the rest of the war our boats were slaughtered at a fearful rate.”

Of all the victories the Allies won during World War II, the U-Boat war was arguably one of the most complete. Of 1,150 commissioned or in commission during the war, Germany had a total of 842 U-Boats that saw battle. Of these, the Allies sank 781 and captured two, accounting for nearly 93 percent of Germany’s operational U-Boat fleet. The remainder were either scuttled by the Germans or surrendered at the end of the war.


Since World War II, the Navy, and the nation in general, have become more and more dependent on cyberspace. A study on the Joint Environment published by Joint Forces Command in 2008 stated: “The crucial enabler for America’s ability to project its military power for the past six decades has been its almost complete control over the global commons. From the American standpoint, the Battle of the Atlantic that saw the defeat of the German U-Boat menace in May 1943 was the most important victory of the Second World War. Any projection of military power in the future will require a similar enabling effort and must recognize that the global commons have now expanded to include the domains of cyber and space. The joint force must have redundancy built into each of these areas to ensure that access and logistics support are more than singlepoint safe and cannot be disrupted through a single enemy attack.”

In the same fashion that the historic TENTH Fleet enabled the prosecution of the U-Boat threat and ensured access to the shipping lanes of the Atlantic, U.S. Fleet Cyber Command and the modern U.S. TENTH Fleet must enable the prosecution of threats in cyber space and ensure the Navy and the Nation have access. In a speech to CSIS, [former] Chief of Naval Operations Gary Roughead said, “The Navy requires unfettered access to assure communication capabilities in cyberspace – it is going to be a pervasive, persistent, and adaptive domain. I believe that having an organization and a Fleet that is looking globally, has the right skills and folks who are trained and experienced in it is the best defense.” Following the demonstrably successful model of the historic TENTH Fleet, today’s TENTH Fleet and Fleet Cyber Command will provide that globally looking, properly trained cadre of personnel.