In January 1917 , the Germans initiated a new policy of unrestricted submarine warfare against ships in the seas around the British Isles .
This was a clear departure from existing practices -- a diplomatic concession from which Germany could only more brazenly withdraw .
In January 1917 , the Germany initiated a new policy of unrestricted submarine warfare against ships in the seas around the British Isles .
This was a clear departure from existing practices -- a diplomatic concession from which Germany could only more brazenly withdraw .