ABSTRACT
German submarine activity at sea in the spring of 1917 surpassed all expectations. In March 1917 the Barents Sea was incorporated into the German war zone, as were the Azores in November. When Greece joined the Allied and Associated Powers on 27 June 1917, her waters were freed for U-boat warfare, and in January 1918 the Canary Islands and the Cape Verdes were included in the German war zone. In fact, Admiral v. Holtzendorff throughout 1917 opposed concentration of U-boats in so-called "wolf packs" in favour of dispersing the submarines and hence also the enemy's escorts as widely as possible. The High Sea Fleet attempted to alleviate the mounting plight of the U-boats. German naval strategy in desperation returned not only to Tirpitz's dream of the Entscheidungsschlacht in the south-central North Sea, "between the Thames and Helgoland", concerning the need for an offensive in the North Sea in order to force the approaches to the Atlantic Ocean.
