or between the large British ships that formed the blockade. (Stewart, p. 20)On February 4, 1915 the Kaiser proclaimed the waters around the British Isles to be a “war zone”. Now neutral and British ships traveled at their own risk. “The Kaiser sent U-boats to implement his declaration”. (Pimlott, p. 40)The radius of the U-boats was 2,000 miles. (Hugh, p. 61) This blockade of the British Isles, what the Germans called Sperrgebiet (prohibited area), could be described as “a rectangle with cut corners.” “ It ran from 20 miles from the Dutch coast to the Terschelling light vessel, then north to Utsire off the Norwegian coast, and then northwest to 62 degrees north at its most northerly point, dropping to 3 miles south to the Danish-owned Faeroe Islands. It reached its most westerly point at 20 degrees west before angling back to the content 20 miles off Cape Finisterre and then extending 20 miles off the neutral Spanish coast to the French frontier. There was also a prohibited zone in the Arctic Ocean, notably the approaches to Archangel and the Kola Peninsula. The Germans declared the waters in the Sperrgebiet closed to traffic, and that all neutral ships entering them would do so at their own risk. The Germans offered to permit one American steamer per week to proceed to Falmouth, provided its hull was marked with prominent red and white vertical stripes and it flew red-and-white-checkered flags at each masthead.” (Halpern, p. 340) The U-boats seemed to be the only way for the Germans to impose a blockade since the British were controlling the surface of the water. At first the undersea attacks were restricted to the Mediterranean, where a few American ships operated. One U-boat sank 72,600 tons of merchant shipping in a single five-week cruise. (Pimlott, p. 40)The United States warned Germany that she would be held responsible for losses of American life and shipping. On May 1, ...
