The English Navy had concentrated on building as many Dreadnought battleships as possible. Nobody belived that the submarine could be just as deadly as the battleships. The 22. of September 1914 three English battleships were sunk by only one German submarine. By November the English fleet sailed to Scapa Flow north of Scotland leaving the North Sea empty. This ment that German battleships freely could bombard the english coast.
In February 1915 Germany declared that the English harbours were warzones. This ment that the Germans would sink all ships, both civilian ships as well as Naval ships. Two month later the English passenger steamer Lusitania were sunk by a German submarine. Three miles from the coast of Ireland Schweiger, captain of the german Sub 20, spotted the Lusitania and fired two torpedoes. The passenger steamer sank in only 18 minutes. The ship carried 1906 persons of which 1098 drowned.
Thanks to their submarines the Germans were winning the war in the autum of 1917. One out of four ships leaving an English harbour never returned and England was getting no supply. The situation was saved by Englands new Prime Minister David Lloyd George who suggested that the ships should form convoys protected by the Royal Navy. The effect was immediate, from then on only one ship out of one hundred was sunk.
