CHAPTER XXIII
Driven to Destruction
Three days later, No. 0916, in company with three other patrol-boats of similar type, left Malta for Grecian waters. They were not alone, for acting as a parent ship was the sea-plane carrier Fleetwing.
Osborne would not have recognized in the Fleetwing one of his old vessels of the Royal British and Pacific Company. In pre-war days she had been employed as an intermediate steamer between Vancouver and Yokohama, calling at Honolulu each way. In those days she was known as the Flightaway, and was painted black, with white deck-houses; she sported two funnels and two masts, the former being colour-washed in a vivid yellow hue.
In her new rôle the renamed vessel was completely disguised. A uniform garb of "battleship grey" covered her from truck to water-line. Her foremast had disappeared, while, from her bows to well abaft the position of her funnels, a long, gradually sloping platform had been built for the purpose of enabling the sea-planes to ascend while the vessel was under way. Then, since the foremost funnel interfered with the "clear run" of the launching platform, it had been removed, and a pair of smaller ones erected in its place, so that the Fleetwing now had three funnels set on a triangular base—two well abreast, the third and original one being on the centre line.
As if these drastic conversions were not enough, the ship had been (to use a nautical expression) "gutted" aft, and a huge tank built in. The top of this was flush with the upper deck, while its base was far below the water-line. In this receptacle were stowed four large "kite" balloons, while adjacent was the necessary gear for inflating and repairing their unwieldy yet necessary fabrics.
Practically the whole of the remaining portions of the main deck was a vast repairing workshop. High-class machines of all sorts and descriptions filled every available space, while a veritable forest of belting gave a stranger the impression that he was in some large factory ashore, rather than on board a converted liner. There were also carpenters', plumbers', shipwrights' and painters' shops—in short, every necessary for the care and maintenance of those delicate yet supremely important adjuncts to a modern navy—the sea-planes.
Had it been considered desirable, the patrol-boats could have been slung on board the parent ship; but, as the weather was fine and the sea comparatively smooth, No. 0916 and her consorts were to proceed under their own power in order to give their crews an opportunity of manoeuvring in company.
Somewhere to the south'ard of Cape Matapan, the Fleetwing received wireless information that a large German submarine had been particularly active in these waters, and, while expressing the advisability of extreme vigilance, the authorities ordered that steps should be taken to capture or destroy the enemy.
Towards the position in which the U-boat was last reported seen, the patrol-boats sped, keeping a far-flung formation extending over a front of three miles. A mile astern came the Fleetwing, while overhead flew a couple of sea-planes of the most recent type.
They were tri-planes with a huge wing-spread of over two hundred feet, the planes being in adjustable sections to ensure compact storage and rapid assemblage. Power was supplemented by means of six 200-horse-power motors, coupled in twin units and driving three 15-feet propellers. While taxi-ing on the surface a water-propeller was provided, giving the sea-plane a speed of fifteen knots; while when in flight her speed could be altered at will, ranging from a minimum of 40 to the terrific rate of 180 miles per hour.
Each of the sea-planes carried a crew of ten men, and was armed with a 3-inch non-recoil quick-firer; while as a specialized means of offence against submarines she carried a torpedo-tube discharging a 3-inch projectile.
The torpedo was fired by the ignition of a small charge of petrol gas, and could be aimed with considerable accuracy. At the head of the weapon was a small fan, the use of which was to prevent premature explosion of the charge on impact with the surface of the water. The depth at which the torpedo exploded could be regulated by adjusting the fan to a certain position on its threaded axis.
The sea-planes had been up for less than ten minutes when a wireless was received reporting the position of the quarry. The U-boat was "sounding" at a depth of twelve fathoms—too deep for the aerial torpedoes to reach with accuracy. Her grey hull could be discerned by the airmen with tolerable ease as she lay upon the sandy bottom.
It was now the Fleetwing's task to get the submarine to bestir herself. The German captain would be too wily to attempt to rise to the surface with the churning of four high-speed propellers sounding over his head. So the patrol-boats eased down while the sea-plane carrier forged ahead, thrashing the water with her twin screws, the sea-planes describing vast circles over the spot where the U-boat lay.
Presently another message was received that the submarine was moving. She was about to take stock of the apparently solitary vessel. If she did rise to the surface the patrol-boats could almost with certainty destroy her, either by gun-fire or by ram. On the other hand, if she exposed the tips of her periscopes only, such tactics would not be likely to result in definite destruction.
Breathlessly Osborne and Webb awaited developments, ready at the first warning to urge No. 0916 at full speed towards the enemy.
Still the sea-planes circled. It was the only means of keeping in touch with their prey, for the former were travelling through the air at fifty miles an hour, compared with the latter's maximum submerged speed of fifteen knots. Trained downwards, and only a few degrees from the perpendicular, were the grey-painted torpedo-tubes of each tri-plane.
Presently the upward movement of the U-boat ceased. Her periscopes rippled the surface. Something glistening shot from the sea-plane nearest overhead. Like a silvery dart the object plunged seawards, struck the water with hardly a splash, and disappeared.
Almost simultaneously a column of foam was hurled skywards, to the accompaniment of a muffled detonation.
"Missed!" was the laconic wireless message from the air-craft that had discharged the missile. "She's heading nor'east."
Two more aerial torpedoes were fired, with no better result than to send the U-boat scurrying off at a depth of ten fathoms. It was now the patrol-boats' turn to take up the pursuit.
Directed by the aerial pilots the four swift craft converged. Then began a sort of marine waltz, the lively vessels dodging to and fro, circling and crossing each other's bows in a most daring fashion —all with the idea of confusing the fugitive U-boat.
In this they succeeded. With their nerves shaken by the narrow escape from the explosions of the torpedoes, and in the knowledge that they were hunted by an unknown number of the dreaded patrol-boats, the Huns were literally in a panic. Their sole idea was to keep at a safe depth and steal away from their pursuers, trusting that the latter would be unable to discern their presence by the "surface wake" and the trail of air-bubbles.
But the U-boat had reckoned without the sea-planes. Remorselessly, the wireless reports from the observers kept the patrol-boats in close touch with their prey. Ceaselessly, the churning of the small yet powerful propellers betokened the grim fact that for once the modern pirate could not shake off pursuit.
Suddenly a huge air-bubble rose to the surface, agitating the water in ever-widening circles. No. 0916, fairly in the thick of the maelstrom, was swept from fo'c'sle to taffrail. Then, almost as quickly as it had risen, the sea calmed down under the influence of a rapidly-spreading patch of iridescent oil.
"How about it?" wirelessed No. 0916.
"Get out of the light and we'll see," was the sea-plane's laconic reply. Then a minute later: "She's properly strafed."
In her blind dash for safety the U-boat had crashed, bows on, against a rock that rose abruptly for ninety feet to within nine fathoms of the surface. In spite of her strong construction the steel bows collapsed like an egg-shell. An inrush of water under terrific pressure followed, and yet another of the Kaiser's boasted submarines had ceased to exist, save as a waterlogged wreck upon the bed of the Mediterranean.