The original intent of the U-boat Command (BdU) was to organize two packs of five boats each; one composed of Type VIIB’s from 7th ("Wegener") flotilla and the other of the larger Type IX’s of 6th ("Hundius") flotilla. In the event, several boats were unavailable, so the operation was adjusted to form a single pack comprised six boats. This arrangement meant forming a unit of different type of vessel, who had not previously operated together.