This estimate was not far short of the actual plans before the German naval authorities. Their realization of the pressing need for action, the tightening blockade, and the desperate possibilities of defeat, made them a trifle unwary. News was flashed abroad many times that revealed this state of mind. For instance, on February 20, 1916, it was announced that cooperative action at sea had been settled upon in accord with the proposals of Archduke Charles Stephen and Prince Henry of Prussia, the kaiser's brother. Such information, whether genuine or not, could only make the Allies redouble their watch. Early in February, 1916, it was established that 70,000 naval reservists had been gathered at Kiel and Helgoland ready for duty on auxiliary vessels and cruisers of newly-formed squadrons. Many facts that pointed to Germany's resolution in the face of odds never reached America. The Ally censors kept Germany's secret well. But the whole world expected that a big engagement would be fought any day. The intervening hours, almost the minutes, might be counted. [Illustration: Kiel Canal.] Then Germany changed her mind. She gave notice that after March 1, 1916, a new submarine campaign would be launched. Certain concessions were granted to the demands of the United States, but it was proposed to consider many vessels as warcraft that other nations regarded as merchant ships. It was agreed that warning should be given passenger vessels unless they made an offensive move. This broad ruling gave Germany a free hand, at least from her own standpoint. The new campaign was widely advertised, a succession of brusque threats and veiled insinuations leading up to a fine climax of publicity. The tactics were those of diplomacy and the drama, with the world for an audience. But the campaign failed to accomplish what had been claimed for it. The number of vessels lost did not materially increase, nor did allied shipping halt. No matter what efforts Germany has made the ports of her enemies never have closed--have in reality been far busier than before the war. And the British navy's nets and traps, and her thousands of patrol boats made the submarine commanders' task ever more difficult. Within a few weeks after the latest German policy was in effect the Allies could again breathe easy. Casualties at sea continued, but there was no general destruction as had been promised.