The question of the introduction of convoys for the protection of merchant ships was under consideration at various times during the war. The system had been employed during the old wars and had proved its value in the case of attack by vessels on the surface, and it was natural that thoughts should be directed towards its reintroduction when the submarine campaign developed. There is one inherent disadvantage in this system which cannot be overcome, although it can be mitigated by careful organization, viz. the delay involved. Delay means, of course, a loss of carrying-power, and when tonnage is already short any proposal which must reduce its efficiency has to be very carefully examined. The delay of the convoy system is due to two causes, (a) because the speed of the convoy must necessarily be fixed by the speed of the slowest ship, and (b) the fact that the arrival of a large number of ships at one time may cause congestion and consequent delay at the port of unloading. However, if additional safety is given there is compensation for this delay when the risk is great. One danger of a convoy system under modern conditions should be mentioned, viz. the increased risk from attack by mines. If ships are sailing singly a minefield will in all probability sink only one vessel—the first ship entering it. The fate of that ship reveals the presence of the field, and with adequate organization it is improbable that other vessels will be sunk in the same field. In the case of a convoy encountering a minefield, as in the case of a fleet, several ships may be sunk practically simultaneously.

During the year 1916, whilst I was still in command of the Grand Fleet, suggestions as to convoys had been forwarded to the Admiralty for the better protection of the ocean trade against attack by surface vessels; but it was pointed out to me that the number of cruisers available for escort work was entirely insufficient, and that, consequently, the suggestions could not be adopted. This objection was one that could only be overcome by removing some of the faster merchant ships from the trade routes and arming them. To this course there was the objection that we were already—that is before the intensive campaign began—very short of shipping.

Shortly after my taking up the post of First Sea Lord at the Admiralty, at the end of 1916, the question was discussed once more. At that time the danger of attack by enemy raiders on shipping in the North Atlantic was small; the protection needed was against attack by submarines, and the dangerous area commenced some 300-400 miles from the British Islands. It was known that unrestricted submarine warfare was about to commence, and that this would mean that shipping would usually be subjected to torpedo attack from submarines when in a submerged condition. Against this form of attack the gun armament of cruisers or armed merchant ships was practically useless, and, however powerfully armed, ships of this type were themselves in peril of being torpedoed. Small vessels of shallow draught, possessing high speed, offered the only practicable form of protection. Shallow draught was necessary in order that the protecting vessels should themselves be comparatively immune from successful torpedo fire, and speed was essential for offensive operations against the submarines.

Convoy sailing was, as has been stated, the recognized method of trade protection in the old wars, and this was a strong argument in favour of its adoption in the late war. It should, however, be clearly understood that the conditions had entirely changed. Convoy sailing for the protection of merchant ships against torpedo attack by submarines was quite a different matter from such a system as a preventive against attack by surface vessels and involved far greater difficulties. In the days of sailing ships especially, accurate station keeping was not very necessary, and the ships comprising the convoy sailed in loose order and covered a considerable area of water. On a strange vessel, also a sailing vessel, being sighted, the protecting frigate or frigates would proceed to investigate her character, whilst the ships composing the convoy closed in towards one another or steered a course that would take them out of danger.

In the circumstances with which we were dealing in 1917 the requirements were quite otherwise. It was essential for the protection of the convoy that the ships should keep close and accurate station and should be able to manoeuvre by signal. Close station was enjoined by the necessity of reducing the area covered by the convoy; accurate station was required to ensure safety from collision and freedom of manoeuvre. It will be realized that a convoy comprising twenty to thirty vessels occupies considerable space, even when steaming in the usual formation of four, five or six columns. Since the number of destroyers or sloops that could be provided for screening the convoy from torpedo attack by submarines was bound to be very limited under any conditions, it was essential that the columns of ships should be as short as possible; in other words, that the ships should follow one another at close intervals, so that the destroyers on each side of the convoy should be able as far as possible to guard it from attack by submarines working from the flank, and that they should be able with great rapidity to counter-attack a submarine with depth charges should a periscope be sighted for a brief moment above the surface, or the track of a torpedo be seen. In fact, it was necessary, if the protection of a convoy was to be real protection, that the ships composing the convoy should be handled in a manner that approached the handling of battleships in a squadron. The diagram on p. 107 shows an ideal convoy with six destroyers protecting it, disposed in the manner ordered at the start of the convoy system.

[Illustration on Page 107, With Caption 'Diagram Illustrating a Convoy of 25 Merchant Ships, With an Escort of 6 Destroyers Zigzagging at High Speed for Protection. the Convoy Shown in Close Order and on Its Normal Course.']

[Illustration on Page 108 Shows, According to Its Caption, 'Typical Convoy and Escort of 10 Trawlers in the Early Days of Convoy.']

How far this ideal was attainable was a matter of doubt. Prior to 1917 our experience of merchant ships sailing in company had been confined to troop transports. These vessels were well officered and well manned, carried experienced engine-room staffs, were capable of attaining moderate speeds, and were generally not comparable to ordinary cargo vessels, many of which were of very slow speed, and possessed a large proportion of officers and men of limited sea experience, owing to the very considerable personnel of the Mercantile Marine which had joined the Royal Naval Reserve and was serving in the Fleet or in patrol craft. Moreover, even the troop transports had not crossed the submarine zone in company, but had been escorted independently; and many naval officers who had been in charge of convoys, when questioned, were not convinced that sailing in convoy under the conditions mentioned above was a feasible proposition, nor, moreover, were the masters of the transports.

In February, 1917, in order to investigate this aspect of the question, a conference took place between the Naval Staff and the masters of cargo steamers which were lying in the London docks. The masters were asked their opinion as to how far their ships could be depended on to keep station in a convoy of 12 to 20 vessels. They expressed a unanimous opinion that it was not practicable to keep station under the conditions mentioned, the difficulty being due to two causes: (1) the inexperience of their deck officers owing to so many of them having been taken for the Royal Naval Reserve, and (2) the inexperience of their engineers, combined with the impossibility of obtaining delicate adjustments of speed by reason of the absence of suitable engine-room telegraphs and the poor quality of much of the coal used. When pressed as to the greatest number of ships that could be expected to manoeuvre together in safety, the masters of these cargo steamers, all experienced seamen, gave it as their opinion that two or possibly three was the maximum number. The opinions thus expressed were confirmed later by other masters of merchant ships who were consulted on the subject. It is to the eternal credit of the British Merchant Marine, which rendered service of absolutely inestimable value to the Empire throughout the war, that when put to the test by the adoption of the convoy system, officers and men proved that they could achieve far more than they themselves had considered possible. At the same time it should be recognized how severe a strain was imposed on officers, particularly the masters, of vessels sailing in convoy.

The matter was kept constantly under review. In February, 1917, the Germans commenced unrestricted submarine warfare against merchant ships of all nationalities, and as a consequence our shipping losses, as well as those of Allied and neutral countries, began to mount steadily each succeeding month. The effect of this new phase of submarine warfare is best illustrated by a few figures.

During the last four months of 1916 the gross tonnage lost by submarine attack alone gave the following monthly average: British, 121,500; Allies, 59,500; neutrals, 87,500; total, 268,500.

In the first four months of 1917 the figures became, in round numbers:

(The United States entered the war on April 6, 1917.)

NOTE.—In neither case is the loss of fishing craft included.

It will be realized that, since the losses towards the end of 1916 were such as to give just cause for considerable anxiety, the later figures made it clear that some method of counteracting the submarines must be found and found quickly if the Allied cause was to be saved from disaster.

None of the anti-submarine measures that had been under consideration or trial since the formation of the Anti-Submarine Division of the Naval Staff in December, 1916, could by any possibility mature for some months, since time was necessary for the production of vessels and more or less complicated matÉriel, and in these circumstances the only step that could be taken was that of giving a trial to the convoy system for the ocean trade, although the time was by no means yet ripe for effective use of the system, by reason of the shortage of destroyers, sloops and cruisers, which was still most acute, although the situation was improving slowly month by month as new vessels were completed.

Prior to this date we had already had some experience of convoys as a protection against submarine attack. The coal trade of France had been brought under convoy in March, 1917. The trade between Scandinavia and North Sea ports was also organized in convoys in April of the same year, this trade having since December, 1916, been carried out on a system of "protected sailings." It is true that these convoys were always very much scattered, particularly the Scandinavian convoy, which was composed largely of neutral vessels and therefore presented exceptional difficulties in the matter of organization and handling. The number of destroyers which could be spared for screening the convoys was also very small. The protection afforded was therefore more apparent than real, but even so the results had been very good in reducing the losses by submarine attack. The protection of the vessels employed in the French coal trade was entrusted very largely to trawlers, as the ships composing the convoy were mostly slow, so that in this case more screening vessels were available, although they were not so efficient, being themselves of slow speed.

For the introduction of a system of convoy which would protect merchant ships as far as their port of discharge in the United Kingdom, there were two requirements: (a) A sufficient number of convoying cruisers or armed merchant ships, whose role would be that of bringing the ships comprising the convoy to some selected rendezvous outside the zone of submarine activity, where it would be met by the flotilla of small vessels which would protect the convoy through the submarine area. It was essential that the ships of the convoy should arrive at this rendezvous as an organized unit, well practised in station-keeping by day, and at night, with the ships darkened, and that the vessels should be capable also of zigzagging together and of carrying out such necessary movements as alterations of course, etc.; otherwise the convoy could not be safely escorted through the danger area. (b) The other essential was the presence of the escorting flotilla in sufficient strength.

It has been mentioned that there was an insufficient number of vessels available for use as convoying cruisers. It was estimated that about fifty cruisers or armed merchant ships would be required for this service if the homeward-bound trade to the British Isles alone was considered. An additional twelve vessels would be necessary to deal with the outward-bound trade. At the time only eighteen vessels were available, and these could only be obtained by denuding the North Atlantic entirely of cruisers.

The situation in regard to destroyers or other fast vessels presented equal difficulties. Early in February, 1917, we had available for general convoy or patrol work only fourteen destroyers stationed at Devonport and twelve sloops at Queenstown, and owing to repairs and the necessity of resting officers and men periodically, only a proportion of these were available at any one time. A number of these vessels were required to escort troop transports through the submarine danger zone. During the month of February six sloops were diverted from their proper work of minesweeping in the North Sea and added to the patrol force at Queenstown, and eight destroyers were taken from the Grand Fleet and sent to southern waters for patrol and escort duty. There were obvious objections to this weakening of the North Sea forces, but it was necessary in the circumstances to ignore them.

This total of forty destroyers and sloops represented the whole available force at the end of February. Simultaneously a careful investigation showed that for the institution of a system of convoy and escort for homeward-bound Atlantic trade alone to the United Kingdom, our requirements would be eighty-one destroyers or sloops and forty-eight trawlers (the latter vessels being only suitable for escorting the slow 6-7-knot ships of the trade from Gibraltar to the United Kingdom). For the outward Atlantic trade from the United Kingdom our estimated requirements were forty-four additional destroyers or sloops.

The deficiency in suitable vessels of this class is best shown by the following table, which reveals the destroyer position at different periods during the year 1917:

[Footnote A: Includes destroyers detached for protection work in other commands.]

[Footnote B: Includes United States destroyers.]

There was the possible alternative of bringing only a small portion of the trade under convoy by taking all the available fast small craft from patrol duty and utilizing them to escort this portion of the trade, but it was felt that as this would leave the whole of the remaining trade entirely without protection, and no fast patrol craft would be on the trade routes to pick up the crews of any merchant ships that might be sunk by submarines, the step was not justified.

The next point for consideration was the possibility of obtaining destroyers or sloops from other sources with which to increase the forces for trade protection. The only commands on which it was possible to draw further were the Grand Fleet, the Harwich and Dover forces, the destroyers of old types working on the East Coast, or the destroyers and "P" boats protecting our cross-Channel communications west of the Dover Command.

It was out of the question to reduce the Harwich or Dover flotillas materially, as we were already running the gravest risks from the inadequacy of these forces to deal with enemy destroyers and submarines operating in southern waters from Zeebrugge or from German ports, and in addition the Harwich Force furnished the sole protection for the weekly convoy running between the Thames and Dutch ports, besides being much required for reconnaissance and offensive operations in the Heligoland Bight so far as it could be spared for this purpose. However, the emergency was such that destroyers were taken from Harwich, as the force obtained new vessels of a faster and more powerful type. The destroyers on the East Coast and in the Portsmouth Command were already inadequate to afford proper protection to the trade and the cross-Channel communications, as evidenced by our losses. Here again, however, in order to meet the very serious situation, some destroyers were eventually transferred to Devonport from Portsmouth, but at the expense of still less protection and fewer opportunities for offensive action against submarines. There remained only the Grand Fleet destroyers on which we could draw yet further. It had always been held that the Grand Fleet required a total force of one hundred destroyers and ten flotilla leaders for the double purpose of screening the ships from submarine attack when at sea and of countering the enemy's destroyers and attacking his heavy ships with torpedo fire in a fleet action. We had gradually built the destroyer force of the Grand Fleet up to this figure by the early spring of 1917, although, of course, it fell far short of requirements in earlier months. It was well known to us that the High Sea Fleet would be accompanied by at least eight flotillas, or eighty-eight destroyers, when proceeding to sea at its selected moment, and it was quite probable that the number might be much higher, as many more vessels were available. At our average moment, even with a nominal force of one hundred destroyers and ten flotilla leaders, we could not expect that more than seventy destroyers and eight leaders would be present with the Fleet, since, in addition to those absent refitting, a considerable number were always engaged on trade protection or anti-submarine work in northern waters which could not join up in time to accompany the Fleet to sea. When the Scandinavian convoy was started in April, 1917, one flotilla leader and six destroyers from the Grand Fleet were used for its protection; other vessels in northern waters also depended on Grand Fleet destroyers for protection. Any further transference, therefore, of destroyers from the Grand Fleet to southern waters for trade protection was a highly dangerous expedient, involving increased risk from submarine attack on the heavy ships in the event of the Fleet proceeding to sea, as well as disadvantages in a Fleet action. The necessity, however, was so great that the risk had to be faced, and for some months of 1917 from eight to twelve Grand Fleet destroyers were used for trade protection in the Atlantic, principally from Irish ports, in addition to those protecting trade in the North Sea.

It is interesting to note the number of persons who claim to have been the first to urge the Admiralty to adopt convoys as a method of protecting merchant ships against submarine attack. The claimants for this distinction are not confined to Great Britain; the great majority of them are people without any knowledge of the sea and naval matters, certainly none of them possessed any knowledge of the number of vessels needed to afford protection to the ships under convoy, nor of the vessels which we could produce for the purpose at the time.

Possibly the facts related above may serve to show that convoys were commenced by Admiralty direction, and that they were started as soon as and extended as rapidly as the necessary protecting vessels could be provided. Those who argued then, or who have argued since, that we should have reduced the number of destroyers with the Grand Fleet will not, I think, meet with any support from those who served in that Fleet, especially from the officers upon whom lay the responsibility for countering any move of the High Sea Fleet.

The entry of the United States into the war early in April eased the situation somewhat. First it was hoped that the United States Navy would assist us with destroyers and other small craft, and secondly it was a fact that the great majority of the material imported into countries contiguous to Germany came from the United States. There was reason to anticipate that steps would be taken by the United States authorities in the direction of some form of rationing of these countries, and in these circumstances it was justifiable to reduce gradually the strength of our blockading squadron of armed merchant vessels known as the 10th Cruiser Squadron. By this means we could at once provide additional vessels to act as convoying cruisers.

Vice-Admiral W.S. Sims had arrived in this country in March, 1917, after passing through an exciting experience, the ship in which he crossed (the United States steamer St. Louis) being mined outside Liverpool. He came to visit me at the Admiralty immediately after his arrival in London, and from that day until I left the Admiralty at the end of the year it was my privilege and pleasure to work in the very closest co-operation with him. My friendship with the Admiral was of very long standing. We had during many years exchanged views on different naval subjects, but principally on gunnery questions. I, in common with other British naval officers who had the honour of his acquaintance, had always been greatly struck by his wonderful success in the post of Inspector of Target Practice in the United States Navy. That success was due not only to his intimate knowledge of gunnery, but also to his attractive personality, charm of manner, keen sense of humour, and quick and accurate grasp of any problem with which he was confronted. It was fortunate indeed for the Allied cause that Admiral Sims should have been selected to command the United States forces in European waters, for to the qualities mentioned above he added a habit of speaking his mind with absolutely fearless disregard of the consequences. This characteristic has led him on more than one occasion into difficulty, but in the circumstances with which we had to deal in 1917 it was just the quality that was needed. It was a very difficult matter for those in authority in the United States, separated as they were by 3,000 miles of sea from the theatres of war, to realize the conditions in European waters, for the Admiralty was not concerned only with the North Sea and Atlantic, and the terse and straightforward reports of Admiral Sims, and his convincing statements, went a long way towards bringing home to the United States people at that time the extreme gravity of the situation and the need for immediate action. He was consistently backed up by that great ambassador, the late Mr. W.H. Page, who also honoured me with his confidence, and to whom I spoke perfectly freely on all occasions.

The assistance from the United States that it was hoped was now in sight made the prospect of success following on the adoption of the convoy system far more favourable, and preparations were put in hand for the institution of an ocean convoy system on a large scale. In order to gain some experience of the difficulties attending the working of cargo ships, directions were given for an experimental convoy to be collected at Gibraltar. The necessary officers were sent out to Gibraltar with orders to assemble the convoy, to instruct the masters in the work that lay before them, and to explain to them the system of sailing, the manner in which the convoy would be handled, and the protection that would be afforded. This naturally took time, and the convoy did not arrive in England until after the middle of May. The experience gained showed, however, that the difficulties apprehended by the officers of the Mercantile Marine were not insuperable, and that, given adequate protection by cruisers and small fast craft, the system was at least practicable. It was accordingly decided to put it into operation at once, and to extend it as rapidly as the increase in the numbers of our destroyers and sloops permitted.

The North Atlantic homeward-bound trade was brought under convoy in May, 1917, and the Gibraltar homeward-bound trade in July, but for some months it was impossible to provide for the institution of a complete convoy system. At first some 40 per cent, of the homeward-bound trade was convoyed. Then the system was gradually extended to include first 60 per cent., then 80 per cent., and finally 100 per cent, of the homeward Atlantic trade and the trade from Gibraltar, trawlers being used as escorts for the Gibraltar trade, as the majority of the ships therein engaged were slow. But trawlers are unsatisfactory escort vessels.

In the early stages of the convoy system difficulties were experienced from the fact that all the available destroyers and most of the sloops were used as escorts, with the result that the ships not under convoy were left with but little protection.