How did the Allies counter threat posed by German u boats?

There were a few actions the Allies did to counter the threat of German submarines in World War I and in World War II. In World War I, we told the Germans that if they continued to sink our ships, which violated our rights as a neutral nation, that we would go to war against Germany. For a period of time, this worked as Germany agreed to stop sinking our ships. However, in 1917, Germany resumed sinking our ships, leading the United States to join World War I on the side of the Allies.

In both World War I and World War II, we used the convoy system to protect our merchant marine. Our navy accompanied our merchant and troop transport ships across the ocean. By the time World War II came, we were using new technology to deal with the threat of Germany submarines. Radar and sonar were used to locate the ships, and depth charges were used to disrupt the operation of the submarines. These tactics and the new forms of technology helped us deal with the threat of the German submarines.