German Experiments with Remote Control During the Last War
By A. E. Sokol
Little information about the use of remote control for ships, planes, or J torpedoes has come out during the present conflict. Doubtless experiments with remote control are being conducted by the warring powers, but the results obtained so far do not appear to have been conclusive or striking enough to warrant publicity. The problem is, however, of such importance, and its successful solution of such potential value, that a brief review of past experience may be of interest.
The idea of remote control of vessels or vehicles is not a new one. In fact, an electrically controlled boat was used in experiments conducted by the British torpedo ship Vernon as long ago as 1885. But these early attempts led to no practical results, because at that time no suitable motors were available and transmission of electric power was still in its infancy. Although these conditions gradually improved during the following decades, the experience gained with electric control was, on the whole, not encouraging, and only Germany continued her efforts persistently and systematically, until a product fit for combat use was developed.
Tests with remote control for torpedoes had been carried on in that country, chiefly in the Siemens plant, from 1906 on. But the use of torpedoes was soon given up and later experiments were made with surface craft, since at that early stage the required apparatus was too bulky and complicated to be carried by a torpedo.
These pre-war trials were still hampered by the lack of motors light and powerful enough to give the vessel sufficient speed, and reliable enough to operate several hours in succession without supervision. The chief problem at that time was thus one of developing small high-speed boats and the proper power plant to drive them. Gliders or hydroplanes did not come into consideration since their hard and jerky motion would damage the delicate control mechanism.
From the beginning the Germans had experimented simultaneously with remote control from land, ships, and airplanes, using cables as well as radio waves. When the war started the problem of control from a land station was considered perfected to such an extent that in 1915 twelve boats were ordered for use in coast defense. These were followed a little later by five additional ones, so that a total of 17 electrically controlled motorboats were built and used by the Germans during the war. They were of 6 tons displacement, 42 feet in length with a beam of 6 feet; equipped with twin gasoline engines totaling 400 lip., they attained a speed of 28 to 30 knots; their fuel tanks permitted them to travel for about 6 hours at full speed, though their radius of action actually depended less on their fuel capacity than on the distance to which the boats were visible from the control station. The fore part of the boat contained a considerable charge of high explosive, some 300 to 450 pounds in weight, which was to detonate upon contact with the enemy, thus destroying the boat itself. Naturally, no crew was carried, the boat being directed by means of electricity which was transmitted to it through an insulated single-core cable of somewhere between 30 and 50 miles in length.
While the boats were being built, control stations were erected at Zeebrugge, Kiel, Travemunde, and other places along the North Sea and Baltic coasts. In order to give them a greater range of vision, these stations were placed on towers about 100 feet high, from which the boats could be seen and directed up to 15 miles from shore. But the first two of the boats were not ready until December, 1915, and they as well as their successors suffered from chronic motor trouble, so that actual use was delayed until 1916. In the meantime the control range was doubled by the interposition of a seaplane equipped with a strong radio sender to overcome interference from the enemy. This plane, protected by a strong fighter escort, accompanied the explosive-filled craft and signaled to the shore operator the direction to give it by means of the controlling cable. The signals needed for that purpose were simple—only starboard, port, or steady. Still later, the destroyer T-146 was equipped to take the small boat on board for more extensive trips and to control it in co-operation with the plane, thus eliminating the shore station and greatly increasing the radius of operation. But all these arrangements proved too cumbersome, and further work was done to eliminate the cable as well as the intermediaries, so as to control the boats directly from the plane by radio alone. Toward the end of 1917 these experiments were finally crowned by success, and remote control, which in the meantime had lost favor, received a new impetus. The new procedure permitted the full utilization of the 200-mile radius of action which the boats possessed, and enabled them to be used offensively instead of purely as a means of coast defense.
Nevertheless, the success achieved by the Germans with remote control did not justify the high hopes originally placed in it. Although some German writers credit the electrically directed boats with a number of sinkings of Allied vessels, such claims are substantiated by neither German nor British official reports. A number of factors accounted for that lack of results. It took a considerable amount of experience and practice to insure the proper team work between destroyer, seaplane, and land station, Several of the small craft were lost during experimentation, and others had to be scuttled to prevent their capture. Recurrent motor trouble reduced the number of boats available for action. Moreover, along the Flanders coast the use of the boats was hindered by the net barricades protecting the British ships and ports. Although the light craft could readily slide over them, their thin cables were easily damaged by the nets, thereby making the boats themselves useless. Such damage as the cause of failure is authenticated in at least one case. On September 11, 1916, the FL8 proceeded from Ostende to attack a group of monitors. Conditions were unusually favorable to the attacker. Nevertheless, some 3,000 yards from its goal the boat stopped. To save it from falling into British hands, the control plane alighted alongside the boat, the observer transferred to it and steered it back to its station.
The result was that at first the British treated this new weapon with contempt and did not deem it worthy of attention. Although the boats were small and low in the water, which made them hard to detect, the “feather” caused by traveling at high speed gave ample warning of their approach and time for protective measures. Moreover, the British had been forewarned of the new danger. On March 1, 1917, the FL 7 struck the mole of Nieuport and, according to German accounts, blasted a hole of some 150 feet in it. Because a troublesome British observation post was thus eliminated, the Germans claim this as a success for their FL boats, although Admiral Bacon considers the action a German blunder.
The introduction of these craft was typical of the manner in which a new idea was given uselessly away by the enemy. The first knowledge we had of the existence of these boats was when one of them ran into the pier at Nieuport. The explosion . . . did no damage, and sufficient fragments of the machinery were recovered to give away the principles of the design.
Nevertheless, in 1917 the FL boats did embark on a career of modest achievement. Several attacks were made on monitors and destroyers, and though they did no damage they had the effect of keeping the British vessels farther away from the German-held coast. On October 28 of that year, however, the FL 12 launched an attack on the heavy monitor Erebus which, together with other units, was operating some 25 miles off Ostend. Directed by the plane overhead, (he motorboat steered right into the group of escorting destroyers, penetrated the heavy artillery barrage laid down by the British vessels, and struck the slow monitor fair amidships. But although the boat’s heavy charge exploded upon contact, the rail around the British ship, and its bulge, rendered the explosion comparatively harmless. Only the bulge of the Erebus was damaged, the ship itself not even leaking. In less than two weeks’ time the monitor was repaired and back in active service. Several similar attempts were made in the following months, but the boats never reached their prey.
In view of this failure, the German Navy gradually lost confidence in the cable-controlled boats and demanded their replacement by radio craft. But when they became available, new difficulties developed, and before these were overcome the war had ended, without an opportunity fully to test the possibilities of radio-controlled craft.
Thus, on the whole, remote control proved to be disappointing in its results. But with a little more luck, better motors, and complete radio control, the little boats might have become formidable enemies. At any rate, even their modest achievements demonstrate the fundamental practicability of remote control for war use. The field of employment is vast, along the coasts as well as on the high seas, above and under water as well as on land and in the air; the potential utility of remote control is practically unlimited.
Moreover, remote control will save human lives and, in contrast to the various “suicide” weapons developed by countries which do not rate human life very highly, it may also prove of considerable value in times of peace. All this combines to indicate that remote control of vessels and torpedoes deserves the same careful attention as that of planes, and it is to be hoped that the credit of its final perfection will go to American genius.