Type of naval warfare in which submarines sink vessels such as freighters and tankers without warning, as opposed to attacks per prize rules (also known as "cruiser rules").
unrestricted submarine warfare
Germany's unrestricted submarine warfare
it was Germany.
unrestricted submarine warfare
Germany's submarine warfare was unrestricted. These attacks led to World War I.
Germany practiced unrestricted submarine warfare.
Answers.com blocks the use of url's in answers given, so we can't help you. But google 'unrestricted submarine warfare WW 1" and those sites will appear.
Help end the British blockade
it referred to sinking ships
To get the blockade lifted.
Unrestricted Submarine Warfare.
American enterance into WWI.