Germany Broke Naval Rules
The Lusitania, owned by the Cunard Shipping Line, set sail in 1906 to carry passengers on trans-Atlantic expeditions. The British Admiralty subsidized the construction of the steamship with the understanding that, if needed, it would be pressed into military service. After World War I began in 1914, the Lusitania continued as a passenger ship, yet it was secretly modified for war.
By February 1915, German naval commanders became aware that British merchants were arming their ships. They knew that both passenger and merchant ships were transporting weapons and supplies from America to Europe. That’s why Germany declared the waters around the British Isles a war zone and stopped obeying international naval “prize laws.” These were laws that warned ships of a submarine’s presence.