Atlantic, Battle of the

Atlantic, Battle of the The submarine offensive by the Axis against Allied shipping in the Atlantic began on 12 January 1942, when a British ship was torpedoed 300 miles east of Cape Cod. U-boats had sunk 1,027 Allied and neutral ships (5,700,204 gross tons) in the Atlantic–Arctic theater by 31 December 1942, at a loss of 106 of their own number. In 1942, the Axis had destroyed Allied tonnage at a rate 15 percent higher than replacements came out of shipyards, but had built over twice as many U-boats as they lost. The tide turned during January–May 1943, when Allied losses of 259 ships (1,549,891 gross tons) were a third less than the previous year’s rate, and Allied ship production began to exceed the tonnage sunk. Axis fortunes were also reversed in the same five months, as the loss of 104 U-boats neutralized the construction of 105 new submarines. The offensive then shifted to the Allies.