(1) To ascertain our present policy and plans.

(2) To inquire as to the changes, if any, that were contemplated in the immediate or more distant future.

(3) To ascertain what further a.s.sistance it was desired that the United States should provide from resources then available or likely to be soon available, and the measures that the United States should take to provide future forces and material.

Papers were prepared under my direction for Admiral Mayo giving full information of our immediate needs, of past procedure and of future plans. As to our needs, the main requests were:

(1) An increase in the number of destroyers, in order to enlarge the convoy system and to provide better protection for each convoy. An additional 55 destroyers were stated to be required for this service.

(2) An increase in the number of convoy cruisers for the same reason. The total addition of cruisers or old battleships was given as 41.

(3) An increase in the number of patrol craft, tugs, etc., for anti-submarine work.

(4) The rapid building of merchant ships.

(5) The supply of a large number of mines for the proposed barrage in the North Sea, and a.s.sistance towards laying them by the provision of United States minelaying vessels.

(6) Aircraft a.s.sistance in the shape of three large seaplane stations on the coast of Ireland, with some 36 machines at each station.

(7) The provision of four coal-burning battleships of the "Dreadnought" type to replace Grand Fleet "Dreadnought" battleships which it was desired to use for other purposes.

Admiral Mayo was informed that some 100,000 mines would be required from the Americans for forming and maintaining that portion of the North Sea Barrage which it was suggested should be laid by them, in addition to the large number that it was proposed that we ourselves should lay in the barrage, and that as the barrage would need patrolling by a large number of small craft, great help would be afforded if the United States could provide some of these vessels. It was estimated at that time that the barrage would absorb the services of some 250 small vessels in order that a sufficient number might be kept constantly on patrol.

It may be of interest to give the history of the North Sea Barrage so far as I can recollect it. Our views on such a scheme were sought by the United States Navy Department in the spring of 1917. Owing to various military circ.u.mstances, even at that time we had no prospect of obtaining mines in adequate numbers for such work for at least nine to twelve months, nor could we provide the necessary craft to patrol the barrage. Our view was that such mines as became available during the last months of 1917 would be more effective if laid nearer to the German North Sea naval bases, and in the Straits of Dover, than at such a distance from these bases as the suggestion involved. Apart from our desire to stop the submarines near their bases, the pros and cons of the scheme were as follows:

The advantages were:

(1) That, except for the difficulty of preventing the submarines from using Norwegian territorial waters for egress, a North Sea Barrage would be a menace to submarines using the Kattegat exit as well as those coming from North Sea bases.

(2) That the enemy would be unable to sweep up the minefield, owing to its distance (over 200 miles) from his bases.

The disadvantages were:

(1) The immense number of mines required-some 120,000, excluding reserves-and the improbability of producing them in Great Britain.

(2) The great depth of water in which many of them were to be moored, a depth in which no mines had ever been successfully laid before; time would be required to devise arrangements that would enable the mines to be laid at such depths.

(3) The very large number of patrol craft that would be needed to force submarines to dive into that portion of the minefield which was safe for surface vessels and the difficulty of maintaining them at sea in bad North Sea weather.

(4) The difficulty of preventing egress by the submarines in Norwegian territorial waters, in which, even if mines were laid, they would have to be moored at such a depth as not to const.i.tute a danger to vessels on the surface.

Shortly after the subject was broached to us we learned that the United States Navy had devised a mine that it was expected would be satisfactory for the purpose of the barrage. An experienced mining officer was at once sent over by us to inspect the mine and to give to the United States officers such a.s.sistance as was possible due to his great knowledge of mining under war conditions.

When he arrived in the United States the mine was still in the experimental stage, but later he reported that it promised to be successful, and in view of the great manufacturing resources in America, it appeared that a considerable proportion of the mines for the barrage could be provided by the United States Navy. Our own efforts to produce a mine suitable for very great depths were also proving successful and antic.i.p.ations as to manufacture were optimistic. Accordingly plans were prepared for a barrage across the North Sea, which were given to Admiral Mayo before he left England on his return to the United States. Without seriously relaxing our mining operations in the Heligoland Bight, and without interfering with our mine barrage on the Folkestone-Grisnez line, we antic.i.p.ated at this time that we could provide mines for our portion of the North Sea Barrage by the time that the United States supply of mines was in readiness to be laid.

Admiral Mayo was also furnished with papers dealing at length with our naval policy at the time and the intended future policy, both in home waters and abroad. Papers were given him relating to our air policy, to the att.i.tude of neutral countries, to the Belgian coast problem, to the blockade, to the defence of trade (including one on the convoy system), to such subjects as the defensive armament of merchant ships with guns, smoke apparatus and mine defence gear, the instruction of the personnel in their use, and the system of issuing route instruction to merchant ships. An important statement was also supplied giving a detailed account of our anti-submarine policy, both at the time and in the future.

These papers gave the fullest information on the naval problem, and were intended to put the United States Naval Department in a position to appreciate the whole position and its many embarra.s.sments, though we realized that these could be appreciated only by those who, like Admiral Sims, were in daily contact with the problems. It will possibly be of further interest if mention is made of some of the points to which attention was drawn.

Admiral Mayo, for instance, was informed that British naval policy was being directed in 1917, as during the remainder of the war, to exerting constant economic pressure upon the enemy with a view to forcing him to come to terms. We also endeavoured to prevent the enemy from interfering with the conduct of the war by ourselves and our Allies. In the effective pursuit of that policy the duty of the Navy involved:

(1) The protection of the sea communications of the Allied armies and the protection of British and Allied trade.

(2) The prevention of enemy trade in order to interfere with his military operations and to exert economic pressure.

(3) Resistance to invasion and raids.

It was pointed out that the question at issue in each case was the control of sea communications, and in order to attain that control permanently and completely the enemy's naval forces both above and below water had to be destroyed or effectually masked. As the weaker German Fleet not unnaturally refused decisive action and as its destruction had hitherto not been achieved, we had adopted a policy of guarding an area between our vital communications and the enemy's ports, and of guarding the areas through which the trade and transports pa.s.sed; these were the only methods of frustrating attacks made either by surface vessels or by submarines which succeeded in reaching open waters. It was pointed out that a combination of these two methods had been in force during the wars of the eighteenth century, blockades being combined with the convoy system and the patrol of local areas by frigates, etc. History, in fact, was repeating itself.

We mentioned that a close blockade of the German North Sea and Baltic ports presented insuperable difficulties under the conditions of modern warfare, and the alternative of controlling the Dover and Norway-Scotland exits to the North Sea had been adopted. The former protected the communications of the armies in France, whilst the two combined covered the maritime communications of the world outside the North Sea and Baltic, and if they could be effectively guarded our first two objects would be attained.

So far as the Dover exit was concerned we stated that the narrowness of the waters, with the consequent risk to the enemy from our mines and torpedoes, had so far acted as a deterrent to his capital ships; we had to depend on the light forces at Harwich and Dover to deal with any enemy surface craft attacking the southern area from German ports.

We pointed out that the control of the Norway-Scotland exit depended upon the presence of the Grand Fleet at Rosyth or at Scapa. This fleet ensured the safety of all the vessels engaged in protecting trade and in hunting submarines outside the North Sea.

Mention was made of the fact that the enemy could not open the sea routes for his own war ships without risking a serious action, and that so far he had shown no inclination to run that risk. The Battle of Jutland having been fought in the previous year, any future movement of the High Sea Fleet into the North Sea would probably be merely with the object of drawing our capital ships into prepared areas so as to bring about a process of attrition by mines and torpedoes. Such a movement had been carried out on August 19, 1916. The reasons which had led to the adoption of the Orkney-Faroe-Iceland blockade line were also explained.

It was pointed out that in the early stages of the war, the foregoing general dispositions had sufficed to protect the Allies' communications and to throttle those of the enemy outside the Baltic. Although enemy cruisers in foreign waters and a few raiding vessels which had evaded the blockade had inflicted losses on trade, losses from such causes could not reach really serious proportions so long as the enemy trusted to evasion and refused to face the Grand Fleet. The danger of serious loss from attack by raiding surface craft had also been greatly minimized by the adoption of the convoy system. But as the enemy's submarines increased in size, efficiency and numbers, the situation had been modified, for evasion by submarines of the command exercised by the Grand Fleet was easy, and our vital sea communications could be attacked by them without the risk of a fleet action.

So far as the protection of trade was concerned, the effect therefore of the submarine campaign had been to remove the barrier established by the Grand Fleet and to transfer operations to the focal areas and approach routes.

As the situation developed, a policy of dealing with the submarines by armed patrol craft and decoy ships in these areas had therefore been put into force. Merchant ships had been armed as rapidly as possible, and in addition efforts had been made to intercept the submarines en route to these areas both in the vicinity of German waters and farther afield.

The great area covered by the approach routes and the increasing radius of submarine operations had made the provision of a sufficient number of patrol vessels a practical impossibility and had led to a general adoption of the convoy system as rapidly as the supply of fast small craft made this possible.

The methods of attacking German submarines before they could reach open waters, by extensive mining in the Heligoland Bight, with the exception of Dutch and Danish territorial waters, were also mentioned.

As regards future naval policy it was pointed out that the enemy submarine campaign was the dominating factor to such an extent that any sustained increase in the then rate of sinking merchant ships might eventually prove disastrous.

Mention was made of the fact that the enemy was still producing submarines faster than the Allies were destroying them; the policy of coping with submarines after they reached the open sea had not as yet been sufficiently effective to balance construction against losses, even in combination with the extensive minefields laid in the Heligoland Bight.

The future policy was therefore being directed towards an attempt at a still more concentrated and effective control in the areas between the enemy's ports and our trade routes, and it was proposed to form some description of block or barrage through which the enemy submarines would not be able to pa.s.s without considerable risk. Four forms had been considered:

(1) A method of blocking either mechanically or by mines all the exits of the submarines from their North Sea or Baltic bases.

(2) A barrage of mines at different depths, from near the surface of the sea to near the bottom.

(3) A combination of deep mines with a patrolling force of surface craft and aircraft whose object would be to force the submarines under the surface into the minefield.

(4) A force of surface craft and aircraft patrolling an area of sufficient extent to prevent submarines coming to the surface to recharge their batteries during the hours of darkness.

Admiral Mayo was informed that in our opinion the first scheme as given above, viz. that of absolutely sealing the exits, was the only radical cure for the evil, but that there were very great difficulties to be overcome before such an operation could be successfully carried out. He was shown the plan that had been prepared for a mechanical block of all the enemy North Sea bases, and he entirely concurred in the impracticability of carrying it out. Such a plan had been advocated by some officers and by other people; it was, of course, most attractive in theory and appealed strongly to those who looked at the question superficially. When, however, a definite operation came to be worked out in detail the difficulties became very apparent, and even enthusiastic supporters of the idea were forced to change their views. It was not a matter for surprise to me that the idea of sealing the exits from submarine bases was urged by so many people on both sides of the Atlantic. It was, of course, the obvious counter to the submarine campaign, and it appealed with force to that considerable section which feels vaguely, and rightly, that offensive action is needed, without being quite so clear as to the means by which it is to be carried out.

In this particular case I informed the clever and able officers to whom the planning of the operation was entrusted that they were to proceed on the a.s.sumption that we intended to seal the enemy's ports somehow, and that they were to devise the best possible scheme, drawing up all the necessary orders for the operations. This was done in the most complete detail and with great care and ingenuity, but at the end there was no difference of opinion whatever as to the inadvisability of proceeding with the operations.

It is to be observed in connexion with this question that sealing the North Sea bases would not have been a complete cure, since submarines could still make their exit via the Kattegat, where we could not block channels without violating the neutrality of other nations.

The final conclusion arrived at was to use a combination of the last three alternatives provided that a satisfactory type of mine could be produced in sufficient numbers and a sufficient supply of small craft provided by ourselves and the United States.