Caused individual merchant/supply ships to get together in convoys.
It eventually pushed Germany into submarine war, which eventually brought the USA into the war.
It was a submarine in World War 1 or 2
World War 1
The submarine.
Yes.
A U-boat was a submarine used by Germany in World War 1 and World War 2.
It was a submarine in world war 1 or 2
Underseaboat.
they copied there butts
5 mph
by Gerrnan submarine
I am not being facetious: The biggest effect of World War I was World War II.