A Twist of Sand

The one I was now examining was a little masterpiece of cartography. The old sailor had taken bearings of the three-topped hill and the entrance channel in relation to the rock in the sea. Small wonder he had called it Curva dos Dunas  -- a Twist of Sand. The entrance channel curved like the whorls of a man's inner ear, swinging sharply north from the entrance and away from its first easterly direction, then doubling back almost on its own course; in between was a bar of what was marked as "hard sand." I thought what a brief end that sand-bar would make of a ship. The channel then swung round northwards in an irregular semi-circle --  north, east, due south and then west again, debouching into a "harbour "contained in the enclosing arms of sand. It was thirty fathoms deep in places. It was something like the Jap base of Truk, in the Pacific, on a much smaller scale. What a funk-hole, I thought to myself. You could not winkle a submarine out of there with a can-opener, and it would be way out of range of the odd sea-search bomber of the South African Air Force at Walvis Bay. To the north lay neutral, largely unknown territory, and to the east the mainland appropriately known as the Skeleton Coast. Yes, that was where NP I was! I'd take Trout down that tortuous channel and sink the super U-boat with torpedoes in the deep water inside! Thank God that interminable box-search was at an end! I'd make for Curva dos Dunas and lie in wait for NP I.

Excitedly I got a ruler and made a rough calculation of my course to the island from Trout's present position. One hundred and sixty degrees. That would bring her nicely to the ten-foot rock -- I'd call it Simon's Rock, in honour of the old sailor who might yet be my salvation --  and, for that matter, the salvation of the fighting fleets and merchantmen in the North Atlantic. The thrill of the chase welled through my veins as I turned again to the beautifully drawn map of the channels into the "inner harbour "of Curva dos Dunas. My island! And in occupation by the most lethal submarine in the world! I could be there by late to-morrow. . . .

The appalling significance of it struck me like an icy sea down the conning-tower hatch. One-six-oh! That was exactly the course we were steering! And we were on that course because -- dear God! -- could it be? Bissett had said the course was steady, and the sound was travelling steadily ahead of us at about seven knots. Course one-six-oh! The homeward-bound course of NP I to her base! Trout was, in fact, trailing along merrily, without any attempt at concealment, behind a nuclear-powered submarine!

I broke out in a cold sweat. The noise, that bursting bubble effect -- it could well be that the Germans, with all their ingenuity, had abandoned the ordinary propeller and were using a form of hydraulic jet propulsion which ejected the water in exactly the same way that a squid sucks water into its gills and expels it again under high muscular pressure, thus providing its enormous speed and motive power. The thoughts tore through my brain. For a submarine fitted like that -- and apparently all the power in the world with which to expel the water -- it would be a double advantage, for those death-dealing, tired, trigger-happy men of the North Atlantic escort groups were accustomed to ordinary propeller noises and this new one would deceive them -- at least at the outset. I knew hydraulic jet propulsion had been tried out with great success on shallow-draught small craft, but its application to anything else -- well, that was a brand-new lesson for the North Atlantic.

Christ! How many precious minutes had I wasted in thinking this out, and for every one of them Trout was in mortal peril! Or had NP I simply not heard us because her hydrophones, listening dead astern, might be confused by the upsurge of ejected water. She had only to change course slightly, and she would hear Trout's asdic, as sure as little fishes were waiting for us at the bottom of the ocean.

I bounded towards Bissett, leaping through the control room as I did so. John and the others there gave me a startled glance.

"Switch that infernal thing off!" I roared to the astonished Bissett. He flicked a switch. I could feel the sweat moistening on my face.

"Same course, same speed ?" I snapped.

"Aye, aye, sir," he replied, wonderment written all over his face.

"How long have you been listening to that -- that -- noise?" I whipped out.

"Ever since you . . ." he began, but stopped at the look on my face. "Nearly two hours, sir," he replied woodenly.

"You could identify it again?" I asked.

"Why, yes sir...."

"Shut off everything, then. I may want you to listen later. But you will not use any of this listening gear without my express permission. Understood?"

"Aye, aye, sir," he replied. There was equal astonishment as I whirled round and entered the control room.

"I'll take over, Number One," I rapped out to John.