On the huge chart already described the convoys, each indicated by a little boat, were shown steadily making their progress toward the appointed rendezvous. Eight or nine submarines, likewise indicated on the chart, were always waiting to intercept them. On that great board the prospective tragedies of the seas were thus unfolding before our eyes. Here, for example, was a New York convoy of twenty ships, steaming toward Liverpool, but steering straight toward the position of a submarine. The thing to do was perfectly plain. It was a simple matter to send the convoy a wireless message to take a course fifty miles to the south where, according to the chart, there were no hidden enemies. In a few hours the little paper boat, which represented this group of ships and which was apparently headed for destruction, would suddenly turn southward, pass around the entirely unconscious submarine, and then take an unobstructed course for its destination. The Admiralty convoy board knew so accurately the position of all the submarines that it could almost always route the convoys around them. It was an extremely interesting experience to watch the paper ships on this chart deftly turn out of the course of U-boats, sometimes when they seemed almost on the point of colliding with them. That we were able constantly to save the ships by sailing the convoys around the submarines brings out the interesting fact that, even had there been no destroyer escort, the convoy in itself would have formed a great protection to merchant shipping. There were times when we had no escorting vessels to send with certain convoys; and in such instances we simply routed the ships in masses, directed them on courses which we knew were free of submarines, and in this way brought them safely into port.
III
The Admiralty in London was thus the central nervous system of a complicated but perfectly working organism which reached the remotest corners of the world. Wherever there was a port, whether in South America, Australia, or in the most inaccessible parts of India or China, from which merchantmen sailed to any of the other countries which were involved in the war, representatives of the British navy and the British Government were stationed, all working harmoniously with shipping men in the effort to get their cargoes safely through the danger zones. These danger zones occupied a comparatively small area surrounding the belligerent countries, but the safeguarding of the ships was an elaborate process which began far back in the countries from which the commerce started. Until about July, 1917, the world's shipping for the most part had been unregulated; now for the first time it was arranged in hard and fast routes and despatched in accordance with schedules as fixed as those of a great railroad. The whole management of convoys, indeed, bore many resemblances to the method of handling freight cars on the American system of transcontinental lines. In the United States there are several great headquarters of freight, sometimes known as "gateways," places, that is, at which freight cars are assembled from a thousand places, and from which the great accumulations are routed to their destinations. Such places are Pittsburg, Buffalo, St. Louis, Chicago, Minneapolis, Denver, San Francisco—to mention only a few. Shipping destined for the belligerent nations was similarly assembled, in the years 1917 and 1918, at six or eight great ocean "gateways," and there formed into convoys for "through routing" to the British Isles, France, and the Mediterranean. Only a few of the ships that were exceptionally fast—speed in itself being a particularly efficacious protection against submarines—were permitted to ignore this routing system, and dash unprotected through the infested area. This was a somewhat dangerous procedure even for such ships, however, and they were escorted whenever destroyers were available. All other vessels, from whatever parts of the world they might come, were required to sail first for one of these great assembling points, or "gateways"; and at these places they were added to one of the constantly forming convoys. Thus all shipping which normally sailed to Europe around the Cape of Good Hope proceeded up the west coast of Africa until it reached the port of Dakar or Sierra Leone, where it joined the convoy. Shipping from the east coast of South America—ports like Rio de Janeiro, Bahia, Buenos Aires, and Montevideo—instead of sailing directly to Europe, joined the convoy at this same African town. Vessels which came to Britain and France by way of Suez and Mediterranean ports found their great stopping place at Gibraltar—a headquarters of traffic which, in the huge amount of freight which it "created," became almost the Pittsburg of this mammoth transportation system. The four "gateways" for North America and the west coast of South America were Sydney (Cape Breton), Halifax, New York, and Hampton Roads. The grain-laden merchantmen from the St. Lawrence valley rendezvoused at Sydney and Halifax. Vessels from Portland, Boston, New York, Philadelphia, and other Atlantic points found their assembling headquarters at New York, while ships from Baltimore, Norfolk, the Gulf of Mexico, and the west coast of South America proceeded to the great convoy centre which had been established at Hampton Roads.
In the convoy room of the Admiralty these aggregations of ships were always referred to as the "Dakar convoy," the "Halifax convoy," the "Hampton Roads convoy," and the like. When the system was completely established the convoys sailed from their appointed headquarters on regular schedules, like railroad trains. From New York one convoy departed every sixteen days for the west coast of England and one left every sixteen days for the east coast. From Hampton Roads one sailed every eight days to the west coast and one every eight days to the east coast, and convoys from all the other convoy points maintained a similarly rigid schedule. The dates upon which these sailings took place were fixed, like the arrivals and departures of trains upon a railroad time-table, except when it became necessary to delay the sailing of a convoy to avoid congestion of arrivals. According to this programme, the first convoy to the west coast left New York on August 14, 1917, and its successors thereafter sailed at intervals of about sixteen days. The instructions sent to shipmasters all over the world, by way of the British consulates, gave explicit details concerning the method of assembling their convoys.
Here, for example, was a ship at New York, all loaded and ready to sail for the war zone. The master visited the port officer at the British consulate, who directed him to proceed to Gravesend Bay, anchor his vessel, and report to the convoy officers for further instructions. The merchant captain, reaching this indicated spot, usually found several other vessels on hand, all of them, like his ship, waiting for the sailing date. The commander of the gathering convoy, under whose instructions all the merchantmen were to operate, was a naval officer, usually of the rank of commodore or captain, who maintained constant cable communication with the convoy room of the Admiralty and usually used one of the commercial vessels as his flagship. When the sailing day arrived usually from twenty to thirty merchantmen had assembled; the commander summoned all their masters, gave each a blue book containing instructions for the management of convoyed ships, and frequently delivered something in the nature of a lecture. Before the aggregation sailed it was joined by a cruiser or pre-dreadnought battleship of the American navy, or by a British or French cruiser. This ship was to accompany the convoy across the Atlantic as far as the danger zone; its mission was not, as most people mistakenly believed, to protect the convoy from submarines, but to protect it from any surface German raider that might have escaped into the high seas. The Allied navies constantly had before their minds the exploits of the Emden; the opportunity to break up a convoy in mid-ocean by dare-devil enterprises of this kind was so tempting that it seemed altogether likely that Germany might take advantage of it. To send twenty or thirty merchant ships across the Atlantic with no protection against such assaults would have been to invite a possible disaster. As a matter of fact, the last German raider that even attempted to gain the high seas was sunk in the North Sea by the British Patrol Squadron in February, 1917.
On the appointed day the whole convoy weighed anchor and silently slipped out to sea. To such spectators as observed its movements it seemed to be a rather limping, halting procession. The speed of a convoy was the speed of its slowest ship, and vessels that could easily make twelve or fourteen knots were obliged to throttle down their engines, much to the disgust of their masters, in order to keep formation with a ship that made only eight or ten; though whenever possible vessels of nearly equal speed sailed together. Little in the newly assembled group suggested the majesty of the sea. The ships formed a miscellaneous and ill-assorted company, rusty tramps shamefacedly sailing alongside of spick-and-span liners; miserable little two-or three-thousand ton ships attempting to hold up their heads in the same company with other ships of ten or twelve. The whole mass was sprawled over the sea in most ungainly fashion; twenty or thirty ships, with spaces of nine hundred or a thousand yards stretching between them, took up not far from ten square miles of the ocean surface. Neither at this stage of the voyage did the aggregation give the idea of efficiency. It presented about as desirable a target as the submarine could have desired. But the period taken in crossing the ocean was entirely devoted to education. Under the tutorship of the convoy commander, the men composing the twenty or thirty crews went every day to school. For fifteen or twenty days upon the broad Atlantic they were trained in all the evolutions which were necessary for coping with the submarine. Every possible situation that could arise in the danger zone was anticipated and the officers and the crews were trained to meet it. They perfected themselves in the signal code; they learned the art of making the sudden manœuvres which were instantaneously necessary when a submarine was sighted; they acquired a mastery in the art of zigzagging; and they became accustomed to sailing at night without lights. The crews were put through all the drills which prepared them to meet such crises as the landing of a torpedo in their engine-room or the sinking of the ship; and they were thoroughly schooled in getting all hands safely into the boats. Possibly an occasional scare on the way over may have introduced the element of reality into these exercises; though no convoys actually met submarines in the open ocean, the likelihood that they might do so was never absent, especially after the Germans began sending out their huge under-water cruisers.
The convoy commander left his port with sealed orders, which he was instructed not to open until he was a hundred miles at sea. These orders, when the seal was broken, gave him the rendezvous assigned by Captain Long of the convoy board in London. The great chart in the convoy room at the Admiralty indicated the point to which the convoy was to proceed and at which it would be met by the destroyer escorts and taken through the danger zone. This particular New York convoy commander was now perhaps instructed to cross the thirtieth meridian at the fifty-second parallel of latitude, where he would be met by his escort. He laid his course for that point and regulated his speed so as to reach it at the appointed time. But he well knew that these instructions were only temporary. The precise point to which he would finally be directed to sail depended upon the movement and location of the German submarines at the time of his arrival. If the enemy became particularly active in the region of this tentative rendezvous, then, as the convoy approached it, a wireless from London would instruct the commander to steer abruptly to another point, perhaps a hundred miles to north or south.
"Getting your convoy" was a searching test of destroyer seamanship, particularly in heavy or thick weather. It was not the simplest thing to navigate a group of destroyers through the tempestuous waters of the North Atlantic, with no other objective than the junction point of a certain meridian and parallel, and reach the designated spot at a certain hour. Such a feat demanded navigation ability of a high order; and the skill which our American naval officers displayed in this direction aroused great admiration, especially on the part of the merchant skippers; in particular it aroused the astonishment of the average doughboy. Many destroyer escorts that went out to meet an incoming convoy also took out one which was westward bound. A few mishaps in the course of the war, such as the sinking of the Justicia, which was sailing from Europe to America, created the false notion that outward-bound convoys were not escorted. It was just as desirable, of course, to escort the ships going out as it was to escort those which were coming in. The mere fact that the inbound ships carried troops and supplies gave stronger reasons, from the humane standpoint, for heavier escorts, but not from the standpoint of the general war situation. The Germans were not sinking our ships because they were carrying men and supplies; they were sinking them simply because they were ships. They were not seeking to destroy American troops and munitions exclusively; they were seeking to destroy tonnage. They were aiming to reduce the world's supply of ships to such a point that the Allies would be compelled to abandon the conflict for lack of communications. It was therefore necessary that they should sink the empty ships, which were going out, as well as the crowded and loaded ships which were coming in. For the same reason it was necessary that we should protect them, and we did this as far as practicable without causing undue delays in forming outward-bound convoys. The Justicia, though most people still think that she was torpedoed because she was unescorted, was, in fact, protected by a destroyer escort of considerable size. This duty of escorting outward-bound ships increased considerably the strain on our destroyer force. The difficulty was that the inbound convoy arrived in a body, but that the ships could not be unloaded and sent back in a body without detaining a number of them an undue length of time—and time was such an important factor in this war that it was necessary to make the "turn-around" of each important transport as quickly as possible. The consequence was that returning ships were often despatched in small convoys as fast as they were unloaded. The escorts which we were able to supply for such groups were thus much weaker than absolute safety required, and sometimes we were even forced to send vessels across the submarine zone with few, if any, escorting warships. This explains why certain homeward-bound transports were torpedoed, and this was particularly true of troop and munition convoys to the western ports of France. Only when we could assemble a large outgoing convoy and despatch it at such a time that it could meet an incoming one at the western edge of the submarine zone could we give these vessels the same destroyer escort as that which we always gave for the loaded convoys bound for European ports.
As soon as the destroyers made contact with an inward-bound convoy, the ocean escort, the cruiser or pre-dreadnought, if an American, abandoned it and started it back home, sometimes with a westbound convoy if one had been assembled in time. British escorts went ahead at full speed into a British port, usually escorted by one or more destroyers. This abandonment sometimes aroused the wrath of the passengers on the inbound convoy. Their protector had dropped them just as they had entered the submarine zone, the very moment its services were really needed! These passengers did not understand, any more than did the people at home, that the purpose of the ocean escort was not to protect them from submarines, but from possible raiders. Inside the danger zone this ocean escort would become part of the convoy itself and require protection from submarines, so that its rather summary departure really made the merchantmen more secure. As the convoy approached the danger zone, after being drilled all the way across the ocean, its very appearance was more taut and business-like. The ships were closed up into a much more compact formation, keeping only such distances apart as were essential for quick manœuvring. Generally the convoy was formed in a long parallelogram, the distance across the front of which was much longer than the depth or distance along the sides. Usually the formation was a number of groups of four vessels each, in column or "Indian file," at a distance of about five hundred yards from ship to ship, and all groups abreast of each other and about half a mile apart. Thus a convoy of twenty-four vessels, or six groups of four, would have a width of about three miles and a depth of one. Most of the destroyers were stationed on the narrow sides, for it was only on the side, or the beam, that the submarines could attack with much likelihood of succeeding. It was usually necessary for a destroyer to be stationed in the rear of a convoy, for, though the speed of nearly all convoys was faster than that of a submarine when submerged, the latter while running on the surface could follow a convoy at night with a fair chance of torpedoing a vessel at early daylight and escaping to the rear if unhampered by the presence of a rear-guard destroyer. It was generally impracticable and dangerous for the submarine to wait ahead, submerge, and launch its torpedoes as the convoy passed over it. The extent to which purely mechanical details protected merchant ships is not understood, and this inability to attack successfully from the front illustrates this point. The submarine launches its torpedoes from tubes in the bow or stern; it has no tubes on the beam. If it did possess such side tubes, it could lie in wait ahead and shoot its broadsides at the convoy as it passed over the spot where it was concealed. Its length in that case would be parallel to that of the merchant ships, and thus it would have a comparatively small part of its area exposed to the danger of ramming. The mere fact that its torpedo tubes are placed in the bow and stern makes it necessary for the submarine, if it wishes to attack in the fashion described, to turn almost at right angles to the course of the convoy, and to manœuvre into a favourable position from which to discharge its missile—a procedure so altogether hazardous that it almost never attempts it. With certain reservations, which it is hardly necessary to explain in detail at this point, it may be taken at least as a general rule that the sides of the convoy not only furnish the U-boats much the best chance to torpedo ships, but also subject them to the least danger; and this is the reason why, in the recent war, the destroyers were usually concentrated at these points.
I have already compared the convoy system to a great aggregation of railroads. This comparison holds good of its operation after it had entered the infested zone. Indeed the very terminology of our railroad men was used. Every convoy nearly followed one of two main routes, known at convoy headquarters as the two "trunk lines." The trunk line which reached the west coast of England usually passed north of Ireland through the North Channel and down the Irish Sea to Liverpool. Under certain conditions these convoys passed south of Ireland and thence up the Irish Sea. The convoys to the east coast took a trunk line that passed up the English Channel. Practically all shipping from the United States to Great Britain and France took one of these trunk lines. But, like our railroad systems, each of these main routes had branch lines. Thus shipping destined for French ports took the southern route until off the entrance to the English Channel; here it abandoned the main line and took a branch route to Brest, Bordeaux, Nantes, and other French ports. In the Channel likewise several "single-track" branches went to various English ports, such as Plymouth, Portsmouth, Southampton, and the like. The whole gigantic enterprise flowed with a precision and a regularity which I think it is hardly likely that any other transportation system has ever achieved.