Yale historian Paul Kennedy charts Allied ‘Victory at Sea’

On May 5, 1943, three wolf packs of German U-boats attacked ONS-5, an Allied merchant convoy sailing from British ports to New York City to retrieve stocks of oil, ores, sheet steel, and other vital war supplies.

Since the beginning of World War II, the Kriegsmarine’s U-boats had menaced Allied shipping in the North Atlantic. In mid-March 1943, wolf packs had ravaged two supply-laden convoys heading to Great Britain, destroying more than 30 cargo ships, while losing just a single submarine. Following this lopsided exchange, Prime Minister Winston Churchill expressed doubts to his War Cabinet that British naval resources were adequate to defeat the U-boat wolf packs.

But the attack on ONS-5 in the stormy seas off Newfoundland unfolded differently. While the U-boats inflicted losses, they also suffered greatly in return. The convoy’s escorts sank seven U-boats and badly damaged seven others.

“What happens on the night of May 5 is truly transformative,” said Paul Kennedy, the J. Richardson Dilworth Professor of History in Yale’s Faculty of Arts and Sciences, whose latest book, “Victory at Sea: Naval Power and the Transformation of the Global Order in World War II” (Yale University Press), a lavishly illustrated and sweeping history that tracks the fortunes of six major navies during the war, describes changes to naval warfare, and documents the rise of American economic and military might.

Kennedy recently discussed the new book during a talk at Yale’s Jackson Institute for Global Affairs, where he serves on the faculty.

A new device the size of a soup plate had helped the Allies turn the tide in the Battle of the Atlantic, Kennedy explained. The Allied warships and aircraft protecting convoy ONS-5 were outfitted with new miniaturized radar that allowed them to spot the U-boats in dense fog and darkness and attack them with depth charges. Two postdoctoral researchers in physics at the University of Birmingham invented the miniaturize radar and Bell Laboratories in the United States mass produced the devices.

The innovation brought misery to German U-boat crews, Kennedy explained. In 1942, the Germans had lost 87 U-boats — a sustainable number given the rate at which Germany was producing new vessels. The following year, the number of sunk German submarines spiked to 244. In 1944, the Allies destroyed 249 U-boats, according to statistics presented in the book.

“In the entire naval war, it is hard to find a better example of a novel technology immediately making a difference to the fight,” Kennedy states in the book.

“Victory at Sea” blends Kennedy’s narrative with statistical charts, detailed maps, and 53 eye-catching watercolors by the late marine artist Ian Marshall depicting events and warships the author describes. Kennedy credited Yale University Press for distributing Marshall’s paintings throughout the book rather than compiling them into inserts as is often done in nonfiction volumes.

In developing his narrative, Kennedy applied an analytical approach that French historian Fernand Braudel developed for his 1949 two-volume masterwork “The Mediterranean and the Mediterranean World in the Age of Phillip II.” In those books, Braudel analyzed history through three levels of causation: a basic level that included geography and climate, a middle level focused on changes in technology and trade, and a top level concerning events, such as great battles.

“Could you do Braudel in the mid-20^th century?” Kennedy asked. “I was going to have a crack at this.”

Along with sharing the story of ONS-5 during his talk, Kennedy discussed a second major turning point that led to the triumph of Allied naval power: The addition of Essex-class aircraft carriers to the Allied Pacific fleet in mid-1943.

While many military historians argue that the Battle of Midway in early June 1942, in which four Japanese aircraft carriers were destroyed, shifted momentum to the Allies in the Pacific, Kennedy noted that by 1943, four of the six carriers that had formed the core of the U.S. fleet at the start of the war had been sunk. America’s ability to rapidly design and produce improved warships and aircraft allowed it to dominate the Pacific by the end of 1943, Kennedy asserted.

The U.S.S. Essex, the first aircraft carrier of its class, arrived in the Pacific with a its full complement of aircraft, including the new Grumman F6F Hellcat fighter, in June 1943. The second carrier arrived in July. A third in August and so on, Kennedy said.

“By the end of 1943, when the U.S. is at last ready to go on the offensive, the U.S. Navy has 10 to 12 new aircraft carriers and thousands of aircraft to carry the fight forward,” he said. “It’s an astonishing transformation and I really wanted to discover why and how it could happen.”

In one of the book’s appendices, Kennedy traced the Hellcat fighter’s chain of production from the mining of bauxite — the ore needed to produce aluminum — in the then-Dutch colony of Suriname, to the production of aluminum in Alcoa refineries in Tennessee, to the manufacturing of parts in East Hartford, Connecticut, to the construction of the planes at the massive Grumman factory at Bethpage, Long Island.

“The end result of this story of wartime production was that unrivaled fighter and fighter-bomber of the Pacific War, the Grumman F6F Hellcat, with its aluminum-clad airframe, lighter than steel and capable of taking enormous punishment from enemy machine gun bullets,” Kennedy writes in the book.

The assembled Hellcats were flown to naval bases in San Diego and Long Beach, California and assigned to newly built Essex-class carriers, which then embarked for Pearl Harbor, he noted.

“Naval historians, I fear to say, especially those describing actions in the Atlantic and Pacific, don’t really bother with that background story,” he said.

By the war’s end, the United States was dominating all other nations in the production of warships, a trend that continued into the Cold War, according to a chart Kennedy shared during his talk.

He ended his presentation with examples of the paintings by Marshall, who died in 2016. One — Kennedy’s favorite — depicts the victorious Allied fleet in Tokyo Bay in 1945. The mast of the battleship U.S.S. Missouri towers in the foreground as Mt. Fuji looms over the horizon.

“Victory has come,” Kennedy said of the scene. “It is all over for the Axis Powers now because they could not take on a power that had such enormous production potential. But it needed time, it needed six years of war in the oceans.”