The very serious and ever-increasing menace of the enemy's submarine attack on trade is by far the most pressing question at the present time.
2. There appears to be a serious danger that our losses in merchant ships, combined with the losses in neutral merchant ships, may by the early summer of 1917 have such a serious effect upon the import of food and other necessaries into the allied countries as to force us into accepting peace terms, which the military position on the Continent would not justify and which would fall far short of our desires.
3. The methods which have been used in the past for attacking submarines are not now meeting with the success which has hitherto attended them. The reasons for our present want of success, or for the difficulties in the way of success, are, firstly, the increased size and radius of action of enemy submarines, which enables them to work in waters so far afield as to make it increasingly difficult to trap them; secondly, the fact that they are attacking more frequently with the torpedo, and that this prevents the use of methods which were applicable to submarines which came to the surface; thirdly, the very powerful gun armament now carried by submarines, which makes them more than a match for our smaller patrol craft, who are therefore unable to work far afield and are forced to some sort of concentration, thus reducing their sphere of action; fourthly the fact that the enemy have become aware of the methods hitherto in use, and are therefore more or less able to avoid destruction by these means.
4. It is therefore essential for the successful conclusion of the war that new methods of attack should be devised, and be put into execution at the earliest possible moment.
5. New methods may involve new weapons which must be provided with great rapidity, and possibly the abolition of old weapons may follow. For instance, the patrol trawler is rapidly becoming ineffective, owing to her low speed and poor armament. If these vessels are retained re-armament is essential.
6. The destroyer, although very effective in confined waters, and when present in large numbers, is ineffective for offence in open waters, as is any other vessel, by reason of the fact that the submarine has a submerged radius of action of well over one hundred miles, and can therefore, even if located, escape with great facility.
7. The destroyer is, of course, very efficient defensively as a screen to individual ships, or to a large number of ships, but, except in more or less confined waters, is not an efficient offensive weapon, because she must, with her present means of offence, actually get into contact with a submarine, or very nearly into contact, which is a difficult matter if the submarine has plenty of sea room.
8. Our present methods of offence against submarines are to a considerable extent due to suggestions put forward by some of the younger officers, and the most promising method of evolving new methods appears to lie in the formation of a small committee of such officers who have shown in the past special inventive aptitude or originality. They should work under some senior officer, who will not only have the energy to carry through with great rapidity any promising suggestions which may be put forward, but will also have the power to so influence those in authority as to overcome all difficulties that may be encountered.
9. There are certain younger officers who are specially marked out for this sort of work. Amongst them I would include Commander Cyril P. Ryan, who has taken one particular line, namely, the evolution of the hydrophone, in which lies one possible solution of the question; Lieutenant Charles D. Burney, who has taken another line, and to whose energy and ingenuity is largely due the introduction of the present defensive measures against mines; and there are no doubt other officers, amongst whom I would include Commodore Ellison, whose work has not brought them into touch with me, but who are known to have shown themselves equally valuable for the purpose desired. What is required is to bring together a number of young officers who have proved themselves to be fitted for the special work required, and to work them under one head who also possesses the qualifications necessary for the post.
10. Lieutenant Burney has, during a recent visit to the fleet, made certain suggestions which may be practicable, and which at any rate should be considered. Amongst other proposals he suggests the use of howitzers designed to throw a series of bombs to cover the probable track of a submarine whose periscope has been sighted; these bombs to be of the nature of "depth charges" and to be so fired that they fall at such distances apart as seriously to injure a submarine should she be "straddled" by the line of charges. Experience with howitzers and trench mortars seems to indicate that such an idea is a feasible proposition, if the difficulty of firing from a rolling platform can be overcome. But the proposal is one which should be tried in view of the extreme importance of the question. It is obvious that unless experiments with such a weapon were pressed forward with great energy, supply could not be made in time for any useful results to be obtained.
11. I am not, however, putting forward concrete proposals. My object in writing this memorandum is to press for the formation of a committee, whose one and only aim should be the production in the shortest possible time, and not later than the spring of 1917, of methods for overcoming the most serious menace with which the Empire has ever been faced. If this committee included officers possessing the necessary qualifications, I should have great hopes that it would be the means of producing quickly some methods by which we should be able with some measure of success to cope with this ever-growing menace. Unless, however, such a committee has almost a free hand in the direction of experiment, is provided with all the necessary staff in the way of draughtsmen and technical experts, and is, moreover, free of the ordinary procedure for obtaining materials and manufacturing weapons, and has at its head an officer such as I have indicated, the effort will be too late.
12. It is a matter of great regret to me that there have been no recent successes against enemy submarines in the vicinity of the northern bases, but the conditions are such as to render success almost impossible.
In the first place, submarines in this locality have so much sea room that it is impracticable to corner them by means of destroyer sweeps when they are sighted, and there is the added difficulty of bad weather for a great part of the year. Secondly, owing to the constant expectation of the fleet being required for sea at short notice, and the serious risks involved by sailing without the destroyer force as a submarine screen, it is not possible to send destroyers far from the base in any numbers or to allow them to get short of fuel.
As stated earlier, it is only in more or less confined waters that surface craft can act with any prospect of success against submarines that keep submerged. It is in the hope we may discover methods of dealing with submarines under such conditions that I urge the action indicated above.
13. There are, of course, other measures which may tend to prolong the period during which our losses do not seriously embarrass the conduct of the war. Under this heading I include a thoroughly organised system of diverting ships with great rapidity from dangerous to safe routes, and the completion of all merchant ships now building in this and the allied countries. The first of these two measures is of course a matter of policy. I forwarded a suggested procedure for consideration last year. The second measure may involve retaining men for the work who would otherwise be at the front or who would be engaged on munition work, but the completion of merchant ships is of even greater importance than the supply of men and munitions. Finally it may quite conceivably be wise policy to divert destroyers from the Grand Fleet and from all other available sources, such as the Humber, Harwich, etc., for a thoroughly organised attack on submarines when it is known that they are operating in considerable numbers in comparatively narrow waters such as the Channel. This would involve demobilising, say, one battle squadron for the time, but even this would be a step worth taking if any success could be achieved thereby. The Fourth Battle Squadron, for instance, might be moved to Rosyth and the flotilla attached to it utilised. It would be best to move the battle squadron to Rosyth first, so that the flotilla might have a better chance of rejoining (if time permitted and the Fleet left for possible action with the High Seas Fleet) than if the Fourth Battle Squadron were retained at a northern base.]