To stop supplies from reaching England
Introduced undersea warfare. They were used by the Germans to destroy British ships.
Because the Germans started sinking or cargo ships with their submarines.
Allied cargo ships were the Germans primary targets.
America's support of the allies led Hitler to attack American ships.
America's support of the allies led Hitler to attack American ships.
America's support of the allies led Hitler to attack American ships.
American submarines sank Japanese merchant ships.
U-Boat
The Germans used submarines to attack Passenger ships, most notably the Lusitania, as well as US supply ships. The Germans also tried to convince Mexico to ally against the USA, as evidenced by the "Zimmerman letter."
Ships try to avoid sinking, submarines sink on purpose...
American citizens died when German submarines sank European ships.
German submarines sank an enormous amount of British and Commonwealth shipping in the Atlantic and for a time in 1916 food stocks in Britain were down to about six weeks' supply. German submarines aslo sank some neutral ships and by sinking American ships they brought the U.S. into the war.