Why did the Germans use their you-boats to sink ships like the lusitania?

The Germans used U-boats to sink ships like the Lusitania as part of their unrestricted submarine warfare strategy during World War I. They aimed to disrupt Allied supply lines and cripple Britain's economy by targeting merchant and passenger ships. The sinking of the Lusitania in 1915, which resulted in significant loss of civilian life, intensified anti-German sentiment and contributed to the U.S. eventually entering the war. This tactic was seen as a necessary measure to weaken the enemy, despite the risks of provoking neutral nations.