On the outbreak of the First World War the 6th Flotilla formed the basis of the Dover Patrol. "Zulu" captured the German sailing ship "Perhns" on 5 August 1914, and collided with sister ship in both August and September that year. On 24 April 1916, "Zulu" took place in a large scale operation off the Belgian coast to lay mines and nets, in an attempt to limit use of the ports of Ostend and Zeebrugge to German U-boats. "Zulu" and laid lines of dan-buoys to mark to positions for the minefields and nets to be laid. In total, 1,565 mines were laid by the minelayers "Princess Margaret", "Orvietto", "Paris" and "Biarritz". The minefield probably caused the loss of one U-Boat, , although at the time it was thought that four or five German submarines had been sunk. The destroyer was badly damaged by shellfire from German coast-defence batteries, while one drifter, "Clover Bank", was sunk by a mine.