The wreck of the U-20 on the Danish coast.

After unsuccessfully stalking two more ships and changing course to avoid British patrols, the U-20 arrives at the German naval base at Wilhelmshaven. Although Schwieger and his crew initially were radioed congratulations on their sinking of the Lusitania by their superiors, the Germans are surprised and stunned by the international outrage that quickly followed. From their perspective, the British Navy’s stopping and confiscation of ships and cargo headed for their country is depriving ordinary Germans of food and other necessities, but unlike the Lusitania victims, they get no outpouring of worldwide sympathy. Instead, the German submariners are reviled as war criminals. Neither the U-20 nor its skipper will make it to the war’s end. The U-20 will run aground in a fog off the Danish coast in November 1916, and Schwieger will be killed in action in September 1917 when another U-boat he is commanding strikes a British mine in the North Sea.

Germany soon receives an official note of protest from President Wilson, who calls the Lusitania sinking contrary to the rules of warfare. German foreign minister Gottlieb von Jagow responds that the U-20 was legally entitled to attack the Lusitania, claiming that the ship was armed with deck guns and that it was transporting Canadian troops—charges that both were untrue. (The British had gone no further than installing gun mounts.)

The Germans also contend that the death toll had been exacerbated by the secondary explosion, which they claimed was caused by a clandestine load of ammunition in the hold, for which the British had "deliberately tried to use the lives of American citizens as protection." (There was some truth to that charge, since the Lusitania's manifest listed 173 tons of rifle and artillery casings.) The White House considers those justifications immaterial.