The northward movement of the Battle Fleet was combined with the establishment of certain cruiser patrol _areas_ in the North Sea. These areas, which were purposely made large, were watched on a regular, organised plan by our Cruiser Squadrons, moving at fairly high speed in such a manner as to reduce the submarine risk to the cruisers to a minimum, whist at the same time they kept as effective a watch as possible, first, to intercept German war vessels that might be covering a raid on our coasts or transports, or trying to reach the open sea to operate against trade, and, secondly, to ensure that all merchant ships entering or leaving the North Sea should be closely examined in order to enforce the blockade. This patrol policy was associated with periodical sweeps of cruisers, supported by the Battle Fleet, down into the southern waters of the North Sea, the object being to catch the enemy’s fleet at sea, if possible, and in any case, owing to our movements being probably reported to the Germans by neutral merchant ships, to make them feel that they could never move a force to sea without the possibility of encountering our Fleet engaged in one of these southern sweeps, which we carried out at irregular intervals. A typical sweep is illustrated in accompanying plans. On these occasions the Battle Fleet was kept strictly concentrated during the southern movement, and was screened as far as possible by destroyers against submarine attack; and at times mine-sweepers were directed to work ahead of the Battle Fleet. When this was not possible, owing to the small number of mine-sweepers available or the state of the weather, some of the older battleships of the 6th Battle Squadron, if they were in company, were stationed ahead of the main Battle Fleet in order that, should a minefield be encountered, these older ships would be the first to strike the mines, thus giving sufficient warning to enable me to manœuvre the more valuable ships clear of the field. This general policy was continued until the attack on the _Theseus_ and loss of the _Hawke_, belonging to the 10th Cruiser Squadron, by submarine attack on October 15th, 1914, showed that even under the dispositions then adopted, our larger cruisers were being risked to too great an extent when working without destroyers in the central part of the North Sea. The next move, therefore, was the withdrawal of the cruiser patrols to a safer position farther to the northward and eastward of the Shetland Islands, this being combined with a watch by the smaller craft on the Fair Island Channel, and on the Pentland Firth approaches to the North Sea. Under these conditions the Battle Fleet was often kept either in a position westward of the Orkneys, where it was in support of the cruisers and at the same time formed a second blockade line, or it cruised to the north and east of the Shetland Islands, the cruiser patrols working farther south.