[2] Most of the big ships of the Grand Fleet had dispersed to the navy's anchorage at Scapa Flow or to other north-eastern ports to watch the northern route from the North Sea into the Atlantic.

A large number of destroyers, flotilla leaders and light cruisers were based at Harwich, under the command of Commodore Reginald Tyrwhitt.

Tyrwhitt was also expected to carry out reconnaissance of German naval activities in the southern parts of the North Sea, and to escort ships sailing between the Thames and the Netherlands.

Their ships were present at the Battles of Heligoland Bight, Texel, and Dogger Bank, and were mobilised after the German raids on Scarborough, Hartlepool and Whitby in 1914, and on Yarmouth and Lowestoft in 1916.

Other regular patrols were mounted in The Downs, an anchorage in the eastern part of the Channel and another net barrage which was laid parallel to the Belgian coast.