21. Since there was limited response to this tactic, Germany expected a similar response to its unrestricted submarine warfare . 22. With the resumption of unrestricted submarine warfare in 1917, U-boats sank ships faster than replacements could be built. 23. During the German campaign of unrestricted submarine warfare and prevented the breakout of the German High Seas Fleet. 24. In order to achieve the required results, the unrestricted submarine warfare has to commence no later than 1 February. 25. Following Germany's resumption of unrestricted submarine warfare on February 1, 1917, during the neutral vessels in a war zone. 26. Almost two years later, in January 1917 the German Government announced it would again conduct full unrestricted submarine warfare . 27. The German government apologized for attacking " Gulflight ", but refused to change its strategy of unrestricted submarine warfare . 28. Bickford's decision not to fire on " Bremen " likely delayed the start of unrestricted submarine warfare in the war. 29. On April 6, 1917, Germany's policy of unrestricted submarine warfare finally compelled the United States to declare war on Germany. 30. He repeatedly warned that the U . S . would not tolerate unrestricted submarine warfare , in violation of international law.
