 At the outbreak of World War I , Königsberg was ordered to attack British commerce around the entrance to the Red Sea . A lack of coal hampered Looff 's efforts ; the British prevented his collier Koenig from leaving Dar es Salaam and purchased all the coal in Portuguese East Africa to deny it to Königsberg . Looff then radioed the German steamer Zieten to warn her against using the Suez Canal , where she would have been confiscated . Königsberg chased after the German freighter Goldenfels , whose officers mistook the ship for a British cruiser and refused to stop . Königsberg was forced to fire a warning shot across the bow of Goldenfels to force the ship to stop so that Looff could warn her captain of the state of war . 
