On the outbreak of war in 1939 Admiral Donitzs U-boat flotillas
consisted of some thirty U-boats fully operational, with only six to
eight at sea at any one time. Their activities were restricted mainly to
the North Sea and British coastal waters.
When France fell in the summer of 1940, the ports in the Bay of Biscay
gave direct access to the Atlantic, and the ability to extend their
reach even to. The Royal Navy was unable to escort convoys much beyond
the Western Approaches. In a short time, the Allies were losing 500,000
tons of shipping a month, every month.
Donitz now looked over the far horizons, America's Eastern Seaboard, the
coasts of Africa, and the Mediterranean, where Allied merchantmen
habitually sailed alone and unprotected. There was a rich harvest to be
gathered in by the long range U-boats, the silent hunter-killers, mostly
operating alone. This book tells their story.