HOW THE SECRET SERVICE FOUGHT THE U-BOATS

New Zealand Herald, Volume LXXVI, Issue 23263, 4 February 1939, Page 1 (Supplement)

HOW THE SECRET SERVICE FOUGHT THE U-BOATS

By E. J. LANDON

'pHE telefunken whine of a Üboat's radio stabbed into the half-light of the dawn. In a wooden hut a hundred miles away the staccato notes came piercing clear through the s.tatic. A British operator swung the pointer of a moving coil and noted the bearing. Wires sprang into activity. With a roar that startled the gulls a seaplane churned a foaming streak, across the water, then rose and headed out to sea.

In the vast world of greying space they met; the- submarine but a small dark shape resting on the water and the seaplane but a speck winging through the sky. They saw each other. The submarine prepared to dive. So did the seaplane. Like a meteor it came streaking down through the clouds, the furious scream of the air through its struts freezing the hearts of the men below. A world-shaking crash and a mountain of water flung up astern marked where the first bomb fell. Death or Escape

The seaplane zoomed up and away ready to turn. In the short respite the men still on the deck below scrambled into the conniing tower. The nose of the submarine sank lower as her diving tanks filled. Moving slowly, she settled until the whole deck was awash and the conning tower itself was breasting the surface of the sea.

Then, like the blast of a hurricane, the seaplane returned, roaring down again in a terrifying swoop of death. A shattering detonation and another leaping mass of water marked the explosion of the gecond bomb. When the pilot next got a chance to look around there was no sign of the submarine. Neither was there any wreckage. Had she escaped or was she lying stricken on the bed of the sea? The report was inconclusive. All it stated with any certainty was that the pilot had read, the U-boat's number, that one bomb fell about twenty yards from its mark and the other about lifty yards away. Modern Radio Beacons

The science of wireless direction finding which made that drama possible over twenty years ago, when the use of radio on the high seas was a possible invitation to death, has undergone many refinements and made much progress. Also, when one thinks of direction finding to-day it is in terms of safety—the saving of life and not the destruction of it. Jt is this humane motive which underlies the provision of radio beacons and similar apparatus, such as is being installed in Auckland for the guidance of the great Imperial living-boats and American Clippers when they come winging in from the ends of the earth. Not only have motives changed, but direction finding systems have changed with them, and there is small doubt but that the system to be used in Auckland will have little in common witli the system used in the Great War, beyond the name. And the apparatus, too, will be unbelievably sleek and efficient to the operator of two decades ago. Yet in those grim days of war, when the science was in its infancy and the apparatus but a seemingly crude assembly of parts, remarkably accurate

Radio's. Use in War and Days of Peace

results were obtained and work of the greatest value was done. The British public, alarmed at the scope of the submarine warfare, knew nothing of this work, which went on ceaselessly day and night as part of the naval intelligence service, for the utmost secrecy enshrouded it. People read in their daily newspapers formidable lists of shipping tonnage sunk by enemy submarines, but they did not know of the silent radio eavesdroppers whose work helped to bring a far greater number of ships safely across the perilous waters, where death and destruction by torpedo was lurking ready to strike. For if the radio detection of a submarine led to its destruction, well and good, but in any case it enabled shipping to be warned to avoid the dangerous area. Destruction or Defence

It is possible that this function of wartime direction finding, the warning of shipping, is, and was, its most valued aspect, for irrespective of the destruction of preying submarines a ship safely home with its cargo has done its job. Time might be lost through steering a circuitous course, or in waiting for an opportunity to slip safely out of harbour, but that, generally, is not likely to weigh against the destruction of the vessel with her entire cargo and loss of human life. Inasmuch as wartime direction finding was aimed at the safety of shipping its motive might be considered a humane one—though that probably depends on the purpose of the ship or the nature of its cargo—but the driving force that made the radio eavesdroppers pounce

the moment they heard the faintest squeak from an enemy submarine's radio was the hope that they would get a good bearing and set moving a train of destruction that would wipe another U-boat from the face of the water. It was 110 casual or rare affair, this spotting the whereabouts of enemy submarines. It was rare, indeed, lor twenty-four hours to pass without at least one, and sometimes three or four, submarines being located in a given area and their positions carefully marked on a chart. If they made sufficient use of their wireless to enable their whereabouts to be detected from (lav to day it was possible more or less faithfully *to record their course and watch their jaunt from port, around the ocean and back home again. Problems of Pursuit Knowing approximately where a submarine is and destroying it are two vastly different things. Kven should it be practicable to despatch an armed vessel to the scene, the submarine will dive at the first sign of danger that comes over the horizon and the chances of finding it are diminished accordingly. And the ocean is a pretty big place to play hide and seek. , Another factor making pursuit and destruction difficult was that tho Üboats almost invariably were detected at night. In the comparative safety of the darkness they came to the surface to recharge their batteries and make their wireless reports to their base. The call preliminaries to the despatch of the message itself were sufficient to v enable the eavesdropper to take a bearing. While positions were being worked out and aggressive measures, if any, being decided upon, the listener was lree to read the message for subsequent decoding by intelligence officers skilled in that work.

Something of the tension under which U-boat crews worked was apparent, even communicable, to tho eavesdropper in his secret eyrie, for, to

the experienced ear, even the mechanical Morse code can take 011 the characteristics and peculiarities, or the mood, of its sender. Haste, nervousness, or perhaps complacency, would betray themselves to the listener. A change of operators would he readily apparent. Given any continuity of reception, such as from the enemy shore stations, iit was possible to work out a sichodulp and know beforehand when a certain operator would come on watch. One could christen him Operator A, or 13. or even Carl or Fritz if so inclined, and, without his knowing anything about it, establish a sort of one-sided friendship with him.

It was possible witli the aid of very little imagination to live through some of the moments of drama being enacted away out in the night; not before one's eyes, certainly, but within one's radio lien ring. The even How of a message from some enemy craft would suddenly take a quickened tempo. Had she scented danger, or prey? There would come, perhaps, a pause, followed by a scrambling of the message almost to a point of illegibility. 1 hen a longer pause. What frantic orders were being given out there in the darkness? Then would come a signal showing that the submarine was about to dive, the message uncompleted. After that, silence. A Great Utility It may be that direction finding in days of peace has few thrills to equal those of wartime intensity. With the application of more and more science to the art of navigation, both on the sea and in the air, much that is wonderful seems commonplace. The direction finder, if it be a man and not an automatic'instrument, may bring in a ship or an aeroplane with the utmost nonchalance; perhaps boredom. But it is surely more of an accomplishment in the scheme of things to bring into port a llying argosy with its human freight alive and safe than to send out a flying fortress laden with bombs and sudden death.