Final answer:
Germany's policy evolved from warning before sinking ships to unrestricted submarine warfare, where they would sink ships without warning, including civilian vessels like the Lusitania.
Step-by-step explanation:
Germany's Policy on Sinking Ships in British Waters During World War I
During World War I, Germany adopted a policy of unrestricted submarine warfare around the waters of Great Britain, deploying their U-boats (submarines) to sink ships without warning. Initially, Germany would surface to give warning before sinking ships, a customary practice in naval warfare.
However, after German submarines were attacked by armed merchant ships during such warnings, they began to attack without warning, which included civilian ships like the RMS Lusitania. Urban outrage and diplomatic strain, especially with the United States, led Germany to restrict submarine warfare for a time but ultimately returned to its unrestricted policy by 1917, which contributed to the United States entering the war.