On October 30th Commodore Tyrwhitt, with the 5th Light Cruiser Squadron and destroyers, left Harwich for another sweep off the Danish coast. His force passed through a position some 70 miles north-west of Heligoland before daylight on the 21st, steered for the Little Fisher Bank, and thence to Harwich. A portion of the Battle Cruiser Fleet kept steam at short notice during the operation, which was unproductive, except for the interception of an ore-laden neutral steamer which was sent in to a British port. On October 30th the _Birkenhead_ and _Liverpool_, newly commissioned light cruisers, left Scapa for a searching and exercise cruise in the northern portion of the North Sea, and returned to Scapa on November 1st. During October squadrons cruised independently in the North Sea from Scapa, as in previous months, by day and at night. The ships of the Battle Cruiser Fleet, as well as the 3rd Battle Squadron from Rosyth and squadrons from Scapa, proceeded to Cromarty, in turn, in order to carry out long-range firing at towed targets in the Moray Firth, being screened from submarine attack by destroyers. Squadrons from Rosyth proceeded also to Scapa to carry out practices. A patrol, comprising the _Sappho_ and eight armed whalers, based on Peterhead, was instituted as a guard against further attempted mine-laying in the Moray Firth. The Peterhead and Cromarty mine-sweeping vessels, which had been working under the Senior Officer of Fleet mine-sweepers (Captain Preston) for the clearance of the Moray Firth mine-field, reverted to their proper commands, and arrangements were made for a constant sweep by mine-sweeping trawlers of the channel along the south shore of the Moray Firth, which was that used by ships based on Cromarty when concentrating with the remainder of the Grand Fleet in the North Sea. It was essential to ensure that this channel was kept clear of mines so long as any portion of the Grand Fleet was based on Cromarty.