Book excerpt: The war mission of the German surface fleet included keeping the Royal Navy out of the Baltic. War against British commerce was the primary task of the German submarines, who hoped to strangle Britain's imports of food and war materials. Disguised Auxiliary cruisers could sidle up to merchant vessels undetected as they were flying a neutral flag, similar to 17th century pirate ships. Completion of the disguised ships was difficult and took its toll on the German dockyard workers and crews, sailing in waters dominated by the Royal Navy. The Battle Summaries chart how the Royal Navy dealt with the threat of these raiders of 70 years ago.