Along with the U-boats , surface commerce raiders ( including auxiliary cruisers ) were used to disrupt Allied shipping in the early years of the war , the most famous of these being the heavy cruisers `` Admiral Graf Spee '' and `` Admiral Scheer '' and the battleship `` Bismarck '' .
Along with the U-boats , commerce raiders and cruisers were used to disrupt Allied shipping in the early years of the war . The most famous of these were the heavy cruisers `` Admiral Graf Spee '' and `` Admiral Scheer '' and the battleship `` Bismarck '' .