 The 700,000 ton target was achieved in only one month, November 1942, while after May 1943 average sinkings dropped to less than one tenth of that figure.By the end of the war, although the U-boat arm had sunk 6,000 ships totalling 21 million GRT, the Allies had built over 38 million tons of new shipping.The reason for the misperception that the German blockade came close to success may be found in post-war writings by both German and British authors.