TheCodeBreakers
boat attacks. And, wrote Churchill, "The Battle of the Atlantic was the
dominating factor all through the war. Never for one moment could we
forget that everything happening elsewhere, on land, at sea, or in the air,
depended ultimately upon its outcome." More than once, the B-Dienst
placed in the hands of the U-boat commanders the knowledge that
brought them to the edge of victory.
In 1941, for example, the B-Dienst read messages to convoys from the
Commander in Chief, Western Approaches, that directed those convoys
from the danger zones just west of the British Isles. With this
intelligence, the U-boat command had no difficulty in deploying its
submarines to the maximum effectiveness. Allied losses mounted steeply.
In March, April, and May, U-boats sank 142 vessels, or more than one
every 16 hours. In January and February of 1943, the B-Dienst mastered
British naval cryptosystems so fully that it was even reading the British
annaabi.ee 
