One ship in 174. That is the ratio of ships torpedoed and sunk that the U.S. Navy’s wartime convoy staff recorded for the 46,000 ships convoyed across the Atlantic between the end of 1939 and VE Day, May 8, 1945. The figure appears in the History of Convoy and Routing, a 1945 administrative history prepared at the Headquarters of the Commander in Chief, United States Fleet.
The history sets that number beside the First World War. Citing the Convoy Section of the British Ministry of Shipping, it says 16,693 ships sailed in convoy in that war, “of which 102 ships, (a ratio of 1:163), were torpedoed and sunk while actually in convoy.” Convoying in World War I, the document notes, “did not commence until April, 1917.”
The full text is posted by the Naval History and Heritage Command in its online reading room. Its cover is marked “Secret Declassified,” and it was issued as No. 11 in the series United States Naval Administration in World War II, covering the work of the convoy and routing organization up to VE Day. The comparison of the two wars sits in Chapter I, which reports “a ratio of 1:174 for the 46,000 ships convoyed across the Atlantic between the end of 1939 and VE Day, 1945.”
What the Navy meant by a convoy
The history defines a convoy as “two or more naval auxiliary vessels, merchant vessels or both,” “assembled and organized for an operation or passage together.” It quotes the governing instruction, MER-1, on the mission of the Merchant Ship Control Service: “to provide for the safety of movements of merchant vessels in time of war.”
Safety was only half the job. The document describes the goal as “to establish and maintain a proper balance between adequate safety for and most efficient use of shipping.” It is candid about the price of convoy: the “reduction in speed of the faster ships to that of the slowest ship in convoy.” Ships judged able to accept the risk sailed alone and were routed singly to their destinations. Among them were what the history calls “‘Monster’ troopships,” large, fast troop carriers that “normally proceed independently.”
The convoy series named in the document include UGS/GUS, UT/TU, CU/UC and OT/TO, the history’s headings show.
From British routing to Tenth Fleet
The routing system predates American entry into the war. “Since the beginning of their war in 1939,” the history says, the British Admiralty, through its Naval Control Service Officers, “maintained a routing, diverting and reporting service, covering all areas except those under control of the Axis.”
On the American side, the history says Convoy and Routing “gradually developed as ‘Ship Movements Division’ since the summer of 1940.” It records that “the coastal convoys were inaugurated on 1 July 1942” and were then extended south through the Caribbean to Trinidad. The document’s own chronology gives an earlier date, May 14, 1942, for the establishment of the coastal convoy system.
The organization took its final wartime shape in 1943. “On 20 May 1943, the TENTH Fleet was organized under the Commander in Chief United States Fleet,” the history says, “to exercise unity of control over U.S. anti-submarine operations in that part of the Atlantic Ocean.” The Convoy and Routing Section was folded into Tenth Fleet’s staff.
NHHC’s account of the 1943 Battle of the Atlantic says Adm. King “appointed himself as its commander,” while his chief of staff, Rear Adm. Francis S. “Frog” Low, “served as a de facto commander.” The fleet, NHHC says, “took control of the U.S. Navy’s antisubmarine warfare (ASW) battle in the Atlantic.”
What 1:174 measures
The ratio counts ships torpedoed and sunk against ships convoyed. It is the history’s direct comparison with the 1:163 First World War figure, and it covers Atlantic sailings from the end of 1939, years before the American coastal convoys the history describes began in 1942.
The 1945 authors drew their own conclusion about the system. Of convoy, they wrote that “its salutary effect during periods of intensive attack is clearly demonstrated,” and they noted that convoy losses in 1943 fell “in spite of greatly increased number of convoyed ships.” That judgment, and the 1:174 ratio behind it, remain on the record in the Navy’s own declassified account.
Top image: A U.S. Navy blimp watches over an Atlantic convoy in June 1943. Image Credit: U.S. Navy / Library of Congress — Public domain / Wikimedia Commons
This article was produced with the assistance of AI and reviewed by Combat Rated editors prior to publication.