four in the morning
The appearance of these transports would be taken by the Germans as an indication of an attempted landing of a British force , and troops would be hurriedly massed to repel the threatened invasion . The monitors were thereupon to fire a certain number of rounds , then , followed in a parallel course by the transports , make for Zeebrugge . Alternate visits to both the Belgian ports in German hands were to be made throughout the day , thereby wearing out the German troops in fruitless marching and counter-marching , and at the same time diverting a strong body of men from a section of the trenches upon which the British troops were to deliver a sudden and unexpected assault . At four in the morning the monitors began to leave Dover Harbour . Thanks to the stringent military precautions taken in the town -- precautions that could with decided advantage be imitated elsewhere -- the presence of spies was almost , if not quite , a matter of impossibility . Unheralded by the Kaiser 's agents , the small yet powerful vessels cleared the entrance to the breakwater and headed for the Belgian coast . An hour later a masthead lamp blinked from the _ Vega _ -- the senior officer 's ship of the patrol flotilla .