It was in the summer of 1918 that the Germans made their only attempt at what might be called an offensive against their American enemies. Between the beginning of May and the end of October, 1918, five German submarines crossed the Atlantic and torpedoed a few ships on our coast. That submarines could make this long journey had long been known. Singularly enough, however, the impression still prevails in this country that the German U-boats were the first to accomplish the feat. In the early autumn of 1916 the U-53—commanded by that submarine officer, Hans Rose, who has been previously mentioned in these pages—crossed the Atlantic, dropped in for a call at Newport, R.I., and, on the way back, sank a few merchant vessels off Nantucket. A few months previous the so-called merchant submarine Deutschland had made its trip to Newport News. The Teutonic press, and even some Germanophiles in this country, hailed these achievements as marking a glorious page in the record of the German navy. Doubtless the real purpose was to show the American people how easily these destructive vessels could cross the Atlantic; and to impress upon their minds the fate which awaited them in case they maintained their rights against the Prussian bully. As a matter of fact, it had been proved, long before the Deutschland or the U-53 had made their voyages, that submarines could cross the Atlantic. In 1915, not one but ten submarines had gone from North America to Europe under their own power. Admiral Sir John Fisher tells about this expedition in his recently published memoirs. In 1914, the British Admiralty had contracted for submarines with Charles M. Schwab, president of the Bethlehem Steel Company. As international law prohibited the construction of war vessels by a nation in wartime for the use of a belligerent with which it was at peace, the parts of ten submarines were sent to Canada, where they were put together. These submarines then crossed the Atlantic under their own power, and were sent from British ports to the Dardanelles, where they succeeded in driving Turkish and German shipping out of the Sea of Marmora. Thus a crossing of the Atlantic by American-built submarines manned by British crews had been accomplished before the Germans made their voyages. It was therefore not necessary for the two German submarines to cross the Atlantic to prove that the thing could be done; but the Germans doubtless believed that this demonstration of their ability to operate on the American coast would serve as a warning to the American people.
We were never at all deceived as to what would be the purpose of such a visit after our entrance into the war. In the early part of 1917 the Allies believed that a few German U-boats might assail our coast, and I so informed the Navy Department at Washington. My cables and letters of 1917 explained fully the reasons why Germany might indulge in such a gesture. Strategically, as these despatches make clear, such attacks would have no great military value. To have sent a sufficient number of submarines to do any considerable damage on the American coast would have been a great mistake. Germany's one chance of winning the war with the submarine weapon was to destroy shipping to such an extent that the communications of the Allies with the outside world, and especially with the United States, would be cut. The only places where the submarine warfare could be conducted with some chance of success were the ocean passage routes which lead to European ports, especially in that area south and south-west of Ireland in which were focussed the trade routes for ships sailing from all parts of the world and destined for British and French ports. With the number of submarines available, the Germans could keep enough of their U-boats at work in these areas to destroy a large number of merchant ships. Germany thus needed to concentrate all of her available submarines at these points; she had an inadequate number for her purpose; to send any considerable force three thousand miles across the Atlantic would simply weaken her efforts in the real scene of warfare and would make her submarine campaign a failure. The cruises of submarines on the American coast would have been very much longer and would have been a much more serious strain on the submarines than were the shorter cruises in the inshore waters of Europe. As has already been explained, the submarine did not differ from other craft in its need for constant repairs and careful upkeep, except that perhaps it was a more delicate instrument of warfare than any other naval craft, and that it would require longer and more frequent periods of overhaul. Any operations carried out three thousand miles from their bases, where alone supplies, spare parts, and repair facilities were available, would have soon reduced the submarine campaign to comparative uselessness; each voyage would have resulted in sinking a relatively small amount of shipping; a great number of submarines would be out of commission at all times for repairs, or would be lost through accidents. The Germans had no submarine bases in American waters and could establish none. Possibly, as the newspaper writer has pointed out, they might have seized a deserted island off the coast of Maine or in the Caribbean, and cached there a reservoir of fuel and food; unless, however, they could also have created at these places adequate facilities for repairing submarines or supplying them with torpedoes and ammunition, such a place would not have served the purpose of a base at all. Comparatively few of the German submarines could have made the cruise to the American coast and operated successfully there so far away from their bases for any considerable time. In the time spent in such an enterprise, the same submarine could make three or four trips in the waters about the British Isles, or off the coast of France, and could sink four or five times the tonnage which could be destroyed in the cruise on the Atlantic coast. In the eastern Atlantic, the submarine could seek its victims in an area comprising a comparatively few square miles, at points where shipping was so dense that a submarine had only to take a station and lie in wait, and be certain, within a short time, of encountering valuable ships which it could attack successfully with its torpedoes. If the U-boats should be sent to America, on the other hand, they would have to patrol up and down three thousand miles of coast, looking for victims; and even when they found them the ships that they could sink would usually be those engaged in the coastwise traffic, which were of infinitely less military importance than the transports which were carrying food, munitions, and supplies to the Allies and which were being sunk in the eastern Atlantic.
Anything resembling an attack in force on American harbours was therefore improbable. Yet it seemed likely from the first that the Germans would send an occasional submarine into our waters, as a measure of propaganda rather than for the direct military result that would be achieved. American destroyers and other vessels were essential to the success of the whole anti-submarine campaign of the Allies. The sooner they could all be sent into the critical European waters the sooner the German campaign of terrorism would end. If these destroyers, or any considerable part of them, could be kept indefinitely in American waters, the Germans might win the war. Any manœuvre which would have as its result the keeping of these American vessels, so indispensable to the Allies, out of the field of active warfare, would thus be more than justified and, indeed, would indicate the highest wisdom on the part of the German navy. The Napoleonic principle of dividing your enemy's forces is just as valuable in naval as in land warfare. For many years Admiral Mahan had been instructing American naval officers that the first rule in warfare is not to divide your fighting forces, but always to keep them together, so as to bring the whole weight at a given moment against your adversary. Two of the fundamental principles of the science of warfare, on land and sea alike, are contained in the maxims: Keep your own forces concentrated, and always endeavour to divide those of the enemy. Undoubtedly, the best method which Germany could use to keep our destroyers in our own waters would be to make the American people believe that their lives and property were in danger; they might accomplish this by sending a submarine to attack our shipping off New York and Boston and other Atlantic seaports, and possibly even to bombard our harbours. The Germans doubtless believed that they might create such alarm and arouse such public clamour in the United States that our destroyers and other anti-submarine craft would be kept over here by the Navy Department, in response to the popular agitation to protect our own coast. This is the reason why American headquarters in London, and the Allied admiralties, expected such a visitation. The Germans obviously endeavoured to create the impression that such an attack was likely to occur at any time. This was part of their war propaganda. The press was full of reports that such attacks were about to be made. German agents were continually circulating these reports.
Of course it was clear from the first, to the heads of the Allied navies and to all naval authorities who were informed about the actual conditions, that these attacks by German submarines on the American coast would be in the nature of raids for moral effect only. It was also quite clear from the first, as I pointed out in my despatches to the Navy Department, that the best place to defend our coast was in the critical submarine areas in the European Atlantic, through which the submarines had to pass in setting out for our coast, and in which alone they could have any hope of succeeding in the military object of the undersea campaign. It was not necessary to keep our destroyers in American waters, patrolling the vast expanse of our three thousand miles of coastline, in a futile effort to find and destroy such enemy submarines as might operate on the American coast. So long as these attacks were only sporadic—and carried out by the type of submarine which used its guns almost exclusively in sinking ships, and which selected for its victims unarmed and unprotected ships—destroyers and other anti-submarine craft would be of no possible use on the Atlantic coast. The submarine could see these craft from a much greater distance than it could itself be seen by them; and by diving and sailing submerged it could easily avoid them and sink its victims without ever being sighted or attacked by our own patrols, however numerous they might have been. Even in the narrow waters of the English Channel, up to the very end of the war, submarines were successfully attacking small merchant craft by gunfire, although the density of patrol craft in this area was naturally a thousand times greater than we could ever have provided for the vast expanse of our own coast. Consequently, so long as the submarine attacks on the American coast were only sporadic, it was absolutely futile to maintain patrol craft in those waters, as this could not provide any adequate defence against such scattered demonstrations. If, on the other hand, the Germans had ever decided to commit the military mistake of concentrating a considerable number of submarines off our Atlantic ports, we could always have countered such a step by sending back from the war zone an adequate number of craft to protect convoys in and out of the Atlantic ports, in the same manner that convoys were protected in the submarine danger zone in European waters. This is a fact which even many naval men did not seem to grasp. Yet I have already explained that we knew practically where every German submarine was at any given time. We knew whenever one left a German port; and we kept track of it day by day until it returned home. No U-boat ever made a voyage across the Atlantic without our knowledge. The submarine was a slow traveller, and required a minimum of thirty days for such a trip; normally, the time would be much longer, for a submarine on such a long voyage had to economize oil fuel for the return trip and therefore seldom cruised at more than five knots an hour. Our destroyers and anti-submarine craft, on the other hand, could easily cross the Atlantic in ten days and refuel in their home ports. It is therefore apparent that a flotilla of destroyers stationed in European waters could protect the American coast from submarines almost as successfully as if it were stationed at Hampton Roads or Newport. Such a flotilla would be of no use at these American stations unless there were submarines attacking shipping off the coast; but as soon as the Germans started for America—a fact of which we could always be informed, and of which, as I shall explain, we always were informed—we could send our destroyers in advance of them. These agile vessels would reach home waters about three weeks before the submarines arrived; they would thus have plenty of time to refit and to welcome the uninvited guests. From any conceivable point of view, therefore, there was no excuse for keeping destroyers on the American side of the Atlantic for "home defence." Moreover, the fact that we could keep this close track of submarines in itself formed a great protection against them. I have already explained how we routed convoys entering European waters in such ways that they could sail around the U-boat and thus escape contact. I think that this simple procedure saved more shipping than any other method. In the same way we could keep these vessels sailing from American ports outside of the area in which the submarines were known to be operating in our own waters.
Yet the enemy sent no submarines to our coast in 1917; why they did not do so may seem difficult to understand, for that was just the period when a campaign of this kind might have served their purpose. During this time, however, we had repeated indications that the Germans did not take the American entrance into the war very seriously; moreover, looking forward to conditions after the peace, they perhaps hoped that they might soon be able once again to establish friendly relations. In 1917 they therefore refrained from any acts which might arouse popular hatred against them. We had more than one indication of this attitude. Early in the summer of 1917 we obtained from one of the captured German submarines a set of the orders issued to it by the German Admiralty Staff. Among these was one dated May 8, 1917, in which the submarine commanders were informed that Germany had not declared war upon the United States, and that, until further instructions were received, the submarines were to continue to look upon America and American shipping as neutral. The submarine commanders were especially warned against attacking or committing any overt act against such American war vessels as might be encountered in European waters. The orders explained that no official confirmation had been received by the German Government of the news which had been published in the press that America had declared war, and that, therefore, the Germans, officially, were ignoring our belligerence. From their own standpoint such a policy of endeavouring not to offend America, even after she became an enemy, may have seemed politically wise; from a military point of view, their failure to attempt the submarine demonstration off our coast in 1917 was a great mistake; for when they finally started warfare on our coast, the United States was deeply involved in hostilities, and had already begun the transportation of the great army which produced such decisive results on the Western Front. The time had passed, as experience soon showed, when any demonstration on our coast would disturb the calm of the American people or affect their will to victory.
In late April, 1918, I learned through secret-service channels that one of the large submarines of the Deutschland class had left its German base on the 19th of April for a long cruise. On the 1st of May, 1918, I therefore cabled to the Department that there were indications that this submarine was bound for our own coast. A few days afterward I received more specific information, through the interception of radio despatches between Germany and the submarine; and therefore I cabled the Department, this time informing them that the submarine was the U-151, that it was now well on its way across the Atlantic, and that it could be expected to begin operations off the American coast any time after May 20th. I gave a complete description of the vessel, the probable nature of her cruise, and her essential military characteristics. She carried a supply of mines, and I therefore invited the attention of the Department to the fact that the favourite areas for laying mines were those places where the ships stopped to pick up pilots. Since at Delaware Bay pilots for large ships were taken on just south of the Five Fathom Bank Light, I suggested that it was not unlikely that the U-151 would attempt to lay mines in that vicinity. Now the fact is that we knew that the U-151 intended to lay mines at this very place. We had obtained this piece of information from the radio which we had intercepted; as there was a possibility that our own cable might fall into German hands, we did not care to give the news in the precise form in which we had received it, as we did not intend that they should know that we had means of keeping so accurately informed. As had been predicted, the U-151 proceeded directly to the vicinity of this Five Fathom Bank off Delaware Bay, laid her mines, and then, cruising northward up the coast, began her demonstration on the 25th of May by sinking two small wooden schooners. These had no radio apparatus, and it was not until June 2nd that the Navy Department and the country received the news that the first submarine was operating. On June 29th I informed Washington that another U-boat was then coming down the west coast of Ireland, bound for the United States, and that it would arrive some time after July 15th. Complete reports of this vessel were sent from day to day, as it made its slow progress across the ocean. On July 6th I cabled that still another U-boat had started for our coast; and the progress of this adventurer, with all details as to its character and probable area of operations, were also forwarded regularly. From the end of May until October there was nearly always one submarine operating off our coast. The largest number active at any one time was in August, when for a week or ten days three were more or less active in attacking coastwise vessels. These three operated all the way from Cape Hatteras to Newfoundland, attempting by these tactics to create the impression that dozens of hostile U-boats were preying upon our commerce and threatening our shores. These submarines, however, attacked almost exclusively sailing vessels and small coastwise steamers, rarely, if ever, using torpedoes. A number of mines were laid at different points off our ports, on what the Germans believed to be the traffic routes; but the information which we had concerning them made it possible to counter successfully their efforts and, from a military point of view, the whole of the submarine operations off our coast can be dismissed as one of the minor incidents of the war, as the Secretary of the Navy described it in his Annual Report. The five submarines sunk in all approximately 110,000 tons of shipping, but the vessels were, for the most part, small and of no great military importance. The only real victory was the destruction of the cruiser San Diego, which was sunk by a mine which had been laid by the U-156 off Fire Island.