Keyes and Tyrwhitt requested support for their operation, in particular bringing the Grand Fleet south and the support of the squadron of six light cruisers commanded by Commodore William Goodenough. This was refused by the Chief of Staff—Vice Admiral Doveton Sturdee—who instead agreed to place only lighter forces consisting of Cruiser Force K (Rear Admiral Gordon Moore) with the battlecruisers and to the north-west and Cruiser Force C comprising the "Cressy"-class armoured cruisers, , , , and , west. The attack was planned for 28 August; the submarines were to sail on 26 August, while Keyes would travel on the destroyer and the surface ships would depart at dawn on 27 August. Tyrwhitt, aboard the brand new light cruiser , would command the 3rd Flotilla of 16 modern L-class destroyers, whilst his subordinate, Captain William Blunt, aboard the light cruiser , would command the 1st Flotilla of 16 older destroyers. Tyrwhitt had requested the replacement of his cruiser because she was too slow to keep up with his destroyers but "Arethusa" did not arrive until 26 August. Her crew were inexperienced and it was discovered that its new Mk V guns jammed when fired. Admiral John Jellicoe, commanding the Grand Fleet, was not told of the plan until 26 August. Jellicoe immediately requested permission to send reinforcements to join the raid and to move the fleet closer to the action but was allowed only to send battle cruisers in support. Jellicoe dispatched Vice Admiral David Beatty with the battlecruisers , and ; and Goodenough with the 1st Light Cruiser Squadron, made up of the light cruisers , , , , and . Jellicoe sailed south from Scapa Flow with the remainder of the fleet. Jellicoe sent a message advising Tyrwhitt that he should expect reinforcements but this was delayed at Harwich and never received. Tyrwhitt did not discover the additional forces until Goodenough's ships appeared through the mist, leading to a certain apprehension because he was expecting to meet only German vessels. The E-class submarines , and were ordered to attack reinforcing or retreating German vessels. , and were positioned further out to draw the German destroyers out to sea. and were stationed off the river Ems to attack reinforcements should they come from that direction. At around 07:00, "Arethusa", steaming south towards the anticipated position of the German ships, sighted a German torpedo boat, .