A change in previous naval practice was considered necessary at an early period, because vessels moving at anything but high speed, particularly in the case of a number of ships in company, ran very considerable risks in waters where we might expect enemy submarines to be operating, unless screened by a strong force of destroyers. This conclusion affected the movements and operations of the Battle Fleet, since the number of destroyers we possessed was quite inadequate to form a screen for a Battle Fleet and a Battle Cruiser Squadron which constantly kept the sea. The number required, for such a screen to be effective, was at least 40 for the Battle Fleet alone as then constituted, and that number, 40, was all that we had stationed at the Northern Base. The fuel capacity of destroyers was only sufficient for them to remain at sea in company with a fleet for some three days and nights, whereas the Fleet itself could remain out for three or four times that period. Moreover, the destroyers could not be kept nearly so constantly at sea as the large ships owing to their requirements in the way of boiler-cleaning and the refit and adjustment of their more delicate machinery, and the necessity for giving not only the machinery, but the personnel, periods of rest. The heavy ships, then, had two alternatives, either to remain at sea without a destroyer screen or to return to harbour with the destroyers. In the early days the first alternative was adopted, the risk being accepted, but minimised as far as possible, by keeping the ships in the northern part of the North Sea.
A further danger soon made itself apparent. It became evident at an early period, as many naval officers had expected, in view of German language at the Hague Conference, that our enemy intended to throw overboard the doctrines of international law when he could gain any advantage by doing so. He accordingly proceeded at once to lay mines in positions where he thought they would be advantageous to his operations, in utter disregard of the safety, not only of British, but also of neutral merchant ships. It was, therefore, thought very probable that he would elaborate this practice by laying mines in the North Sea in positions where he anticipated they might prove effective against the Grand Fleet, and that he would do this without issuing any warning to neutral countries. Consequently, if the main Battle Fleet were kept moving continuously in the central and southern waters of the North Sea, in which waters the enemy could easily lay mines with little danger of his operations being witnessed (as he could carry them out under cover of darkness), it was evident that considerable risks might be incurred without our being aware of the fact. The policy of attrition of our Battle Fleet might thus be carried out with such success as to produce equality, or even inferiority, on the part of the British Fleet as compared with the German, in a comparatively short space of time. The only safeguard against such action which we could take would be to keep mine-sweepers constantly working ahead of the Battle Fleet. But the number of mine-sweepers that we possessed was wholly inadequate for such a task; and even if this had not been so, to carry out such an operation would have necessitated the speed of the Battle Fleet being reduced to some 10 knots, the maximum sweeping speed of mine-sweepers, and it would have been forced also to steer a steady course without zigzagging, conditions rendering the battleships exceedingly vulnerable to submarine attack.
The first effect, therefore, of the submarine menace, combined with possible German action in regard to mine-laying, was to cause the Battle Fleet to confine its movements under ordinary conditions to the more northern waters of the North Sea, where the risk might be taken of cruising without the presence of a screen of destroyers, and where it was improbable, owing to the depth of water and the distance from enemy bases, that the Germans would be able to lay mines without discovery.
The fact that this course of action would be forced upon us as the submarine and destroyer menace grew had often been present in my mind in pre-War days, when I had expressed the view that the beginning of a naval war would be a conflict between the small craft, whilst the larger and more valuable vessels were held aloof. I have no doubt that this opinion was very generally held by officers of experience.
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.
In all the dispositions which were made for a watch on the northern entrance to the North Sea, the principle kept in mind was the necessity for such an organisation of the patrols as to have, in so far as numbers permitted, two lines, or two areas, watched. The two areas were at such a distance apart that vessels moving in or out of the North Sea were forced, so far as all human foresight could provide, to pass through the waters occupied by one of the two groups of ships during daylight hours; the distances apart were regulated according to the length of the night at the different seasons of the year.
As the Battle Fleet worked farther to the northward and westward, it became possible to make use of the heavy ships to assist in blockade work without running undue risks from submarines, and the blockade increased correspondingly in effectiveness. As time went on, however, the provision by the Admiralty of a larger number of armed merchant cruisers enabled us to establish an effective blockade line by the use of these vessels alone, backed up by Cruiser Squadrons when such were available. The withdrawal of the Battle Fleet to more northern and western waters first took effect when the Fleet Base was shifted temporarily from Scapa to Lough Swilly. When this occurred, it did not affect the policy of frequent cruiser sweeps into the southern portion of the North Sea, supported by the Battle Fleet, which were still continued.