Until August of 1940, when the British Navy switched codes, the Germans were reading a steady flow of traffic which supplied BdU with precise intelligence for coordinating and planning u-boat attacks.

• 直到1940年8月，英国海军改变了密码，德国准备进行固定的流通为潜艇指挥部提供严密准确的情报来调整和组织U艇攻击。