This title follows from New Vanguard 51: Kriegsmarine U-boats 1939-45
(1) and charts the continuing development of the U-boat in German
service, including the evolution of the Type IX as a long range
'cruiser' intended for solo operations in distant waters. Also covered
is the revolutionary Type XXI, conceived of in 1942 and launched in
April 1944, the first true submarine rather than submersible, whose
arrival was just too late to influence the war. Other vessels covered
are the Type XXIII, a small vessel armed with only two torpedoes but
technically highly advanced, and the Type X minelayers, which were
rarely used in their intended role and more often used as supply boats.