For the larger part of the war, the Germans had had a great gun stationed in Belgium bombarding Dunkirk. The original purpose in sending American naval batteries to France was to silence this gun. The proposal was made in November, 1917; but, rapidly as the preparations progressed, the situation had entirely changed before our five fourteen-inch guns were ready to leave for France. In the spring of 1918 the Germans began the great drive which nearly took them to the Channel ports; and under the conditions which prevailed in that area it was impossible to send our guns to the Belgian coast. Meanwhile, the enemy had stationed a gun, having a range of nearly seventy-five miles, in the forest of Compiègne; the shells from this weapon, constantly falling upon Paris, were having a more demoralizing effect upon the French populace than was officially admitted. The demand for the silencing of this gun came from all sides; and it was a happy coincidence that, at just about the time when this new peril appeared, the American naval guns were nearly ready to be transported to France. Encouraged by the success of this long-range gun on Paris, the Germans were preparing long-range bombardments on several sections of the front. They had taken huge guns from the new battle-cruiser Hindenburg and mounted them at convenient points for bombarding Dunkirk, Chalons-sur-Marne, and Nancy. In all, the Allied intelligence departments reported that sixteen guns of great calibre had left Kiel in May, 1918, and that they would soon be trained upon important objectives in France. For this reason it was welcome news to the Allies, who were deficient in this type of artillery, that five naval fourteen-inch guns, with mountings and ammunition and supply trains, were ready to embark for the European field. The Navy received an urgent request from General Pershing that these guns should be landed at St. Nazaire; it was to be their main mission to destroy the "Big Bertha" which was raining shells on Paris, and to attack specific points, especially railroad communications and the bridges across the Rhine.
The initiative in the design of these mobile railway batteries was taken by the Bureau of Ordnance of the Navy Department, under Rear-Admiral Ralph Earle, and the details of the design were worked out by the officers of that bureau and Admiral Plunkett. The actual construction of the great gun mounts on the cars from which the guns were to be fired, and of the specially designed cars of the supply trains for each gun, was an engineering feat which reflects great credit upon the Baldwin Locomotive Works and particularly upon its president, Mr. Samuel M. Vauclain, who undertook the task with the greatest enthusiasm. The reason why our naval guns represented a greater achievement than anything of a similar nature accomplished by the Germans was that they were mobile. Careful observations taken of the bombardment of Dunkirk revealed the fact that the gun with which it was being done was steadily losing range. This indicated that the weapon was not a movable one, but that it was firmly implanted in a fixed position. The seventy-five mile gun which was bombarding Paris was similarly emplaced. The answering weapon which our ordnance department now proposed to build was to have the ability to travel from place to place—to go to any position to which the railroad system of France could take it. To do this it would be necessary to build a mounting on a railroad car and to supply cars which could carry the crews, their sleeping quarters, their food and ammunition; to construct, indeed, a whole train for each separate gun. This equipment must be built in the United States, shipped over three thousand miles of ocean, landed at a French port, assembled there, and started on French railroads to the several destinations at the front. The Baldwin Locomotive Works accepted the contract for constructing these mountings and attendant cars; it began work February 13, 1918; two months afterward the first mount had been finished and the gun was being proved at Sandy Hook, New Jersey; and by July all five guns had arrived at St. Nazaire and were being prepared to be sent forward to the scene of hostilities. The rapidity with which this work was completed furnished an illustration of American manufacturing genius at its best. Meanwhile, Admiral Plunkett had collected and trained his crews; it speaks well for the moral of the Navy that, when news of this great operation was first noised about, more than 20,000 officers and men volunteered for the service.
At first the French, great as was their admiration for these guns and the astonishingly accurate marksmanship which they had displayed on their trials, believed that their railroad beds and their bridges could not sustain such a weight; the French engineers, indeed, declined at the beginning to approve our request for the use of their rails. The constant rain of German shells on Paris, however, modified this attitude; the situation was so urgent that such assistance as these American guns promised was welcome. One August morning, therefore, the first train started for Helles Mouchy, the point from which it was expected to silence the "Big Bertha." The progress of this train through France was a triumphant march. Our own confidence in the French road bed and bridges was not much greater than that of the French themselves; the train therefore went along slowly, climbed the grades at a snail's pace, and took the curves with the utmost caution. As they crossed certain of the bridges, the crews held their breath and sat tight, expecting almost every moment to crash through. All along the route the French populace greeted the great battery train with one long cheer, and at the towns and villages the girls decorated the long muzzle of the gun with flowers. But there were other spectators than the French. Expertly as this unusual train had been camouflaged, the German airplane observers had detected its approach. As it neared the objective the shells that had been falling on Paris ceased; before the Americans could get to work, the Germans had removed their mighty weapon, leaving nothing but an emplacement as a target for our shells. Though our men were therefore deprived of the privilege of destroying this famous long-range gun, it is apparent that their arrival saved Paris from further bombardment, for nothing was heard of the gun for the rest of the war.
The guns proved exceedingly effective in attacking German railroad centres, bridges, and other essential positions; and as they could be fired from any point of the railroad tracks behind the Western Front, and as they could be shifted from one position to another, with all their personnel and equipment, as fast as the locomotives could haul them, it was apparent that the more guns of this design that could be supplied the better. These qualities were at once recognized by the Army, which called upon the Navy for assistance in building a large number of railway batteries; and if the war had continued these great guns would soon have been thundering all along the Western Front.
From the time the naval guns were mounted until the armistice Admiral Plunkett's men were busy on several points of the Allied lines. In this time the five naval guns fired 782 shells at distances ranging from 18 to 23 miles. They played great havoc in the railroad yards at Laon, destroying large stretches of track that were indispensable to the Germans, and in general making this place practically useless as a railroad centre. Probably the greatest service which they rendered to the cause of the Allies was in the region north of Verdun. In late October three naval batteries were brought up to Charny and Thierville and began bombarding the railroad which ran through Montmédy, Longuyon, and Conflans. This was the most important line of communication on the Western Front; it was the road over which the German army in the east was supplied, and there was practically no other line by which the great German armies engaging the Americans could escape. From October 23rd to the hour when the armistice was signed our fourteen-inch guns were raining shells upon this road. So successful was this bombardment that the German traffic was stopped, not only while the firing was taking place, but for several hours each day after it had ceased. What this meant to the success of the Allied armies the world now knows. The result is perfectly summed up in General Pershing's report:
"Our large calibre guns," he says, "had advanced and were skilfully brought into position to fire upon the important lines at Montmédy, Longuyon, and Conflans; the strategical goal which was our highest hope was gained. We had cut the enemy's main line of communications and nothing but surrender or an armistice could save his army from complete disaster."
These guns were, of course, only one of many contributing factors, but that the Navy had its part in this great achievement is another example of the success with which our two services co-operated with each other throughout the war—a co-operation which, for efficient and harmonious devotion to a common cause, has seldom, if ever, been equalled.