CHAPTER X
THE BLIMP TO THE RESCUE
"YOU'RE wanted on the 'phone, sir. Senior Officer Trecurnow Base is speaking."
Flight-Lieutenant Barcroft, V.C., was coming away from the airship sheds when a petty officer brought the urgent message that Sir George Maynebrace wanted him on the telephone.
The lieutenant was acting-commander of a "wing" of coastal airships stationed at Toldrundra Cove, within ten miles of Trecurnow Base. During the last few days "business" had been slack. Regularly the Blimps flew over their allotted patrolling districts without sighting a single one of the Kaiser's underwater boats. It looked as if the German submarine had given up the chops of the Channel as a bad job.
It was a great blow to Billy Barcroft when, consequent upon injuries received in a seaplane raid, the Medical Board refused to allow him to fly again in a machine heavier than air. As a partial compensation he was appointed to the airship branch, which, although lacking the opportunities of raiding, was not devoid of excitement and danger.
144A, the Blimp in which Barcroft had just completed the morning flight, consisted of a cigar-shaped envelope one hundred and twenty feet in length, and with an extreme girth of ninety feet. Suspended from the envelope by a ramification of light but enormously strong wire cables was a four-seated fuselage, similar to, but on a slightly larger scale than, the bodies of the battle-seaplanes. Fore and aft was mounted a machine-gun, while projecting through the floor of the fuselage was a complicated arrangement that at first sight looked like three drain-pipes with mushroom heads and a small crowd of "gadgets" thrown in. This was the aerial torpedo projector, a highly perfected apparatus capable of hurling its sinister missiles with uncanny accuracy. The 'midship section of the fuselage was taken up by the propelling machinery—a petrol motor coupled direct to the shafting of a huge aerial propeller.
Aft was the wireless installation, the petty officer occupying the dual rôle of machine-gunner and telegraphist. Underneath the chassis were the emergency water ballast tanks, but for normal alterations of altitude the Blimp depended upon her elevating rudders and also upon the reduction or addition of gas in the envelope—the reserve of hydrogen being kept under pressure in strong metal cylinders.
Hastening to the air-station office Barcroft entered the telephone cabinet and picked up the receiver.
"Yes, sir; Barcroft," he replied in answer to the senior officer's inquiry.
"Look here, Barcroft," resumed Sir George. "'Tantalus' has been submarined. She's still afloat. Her reported position is—— Got that down? Good. There's something very fishy about the business. The escorting destroyers had just returned under wireless orders from goodness only knows who. I am sending 'Antipas' and other destroyers to 'Tantalus's' assistance. I want a coastal airship to be on the spot with the utmost dispatch."
"Very good, sir," rejoined the flight-lieutenant.
"And," added Sir George Maynebrace drily, "I might add for your information that there are no British submarines operating within fifty miles of the given position. Good luck, Mr. Barcroft. Ring off."
Replacing the receiver Barcroft doubled back towards the sheds, adjusting his leather flying helmet as he ran. Half way across the large open space he encountered Kirkwood, the O.C. of Coastal Airship No. 144B, which was undergoing slight adjustments.
"Hullo, Bobby!" exclaimed Barcroft. "You're just the bounder I wanted. Look here, my sub's crocked—sprained his wrist. I had to push him into sick quarters not ten minutes ago."
"You want to pinch my sub, then, Billy?" asked Kirkwood with a smile.
"No," was the reply. "It's you I'm after, old man. The 'Tantalus' has been torpedoed, and I'm off to see what's to be done."
"Good enough!" exclaimed Kirkwood. "I'm ready. Grub on board, I hope?"
"Enough for a month on the Rhondda scale," replied Barcroft. "At any rate, there'll be sufficient even for your huge appetite.... Messenger!"
"Sir?"
"Rout out Anderson and Bell. Tell them we must get under way in five minutes."
Quickly the preparations for the urgent flight were completed. Squads of mechanics set to work, each man knowing exactly what was required of him, and doing it expeditiously and without undue noise. The petrol tank was filled by means of hose pipes communicating with the distant fuel reservoir, hydrogen was pumped into the pressure cylinders and thence into the envelope, until the manometer registered the requisite lifting power. Machine-gun ammunition was already on board, but the deadly aerial torpedoes, risky missiles to handle even with the safety caps in position over the sensitive detonating mechanism, had to be brought from a store at some distance from the sheds.
While this work was in progress, Barcroft and Kirkwood were busily engaged in testing controls and supervising the work of the mechanics. Long experience had taught them that "if you want a thing to be well done, you must do it yourself"; failing that, the next best course is personally to overlook the job.
Presently the two remaining members of the Blimp's complement hurried up. It occasioned them no surprise to be turned out almost as soon as one cruise had been completed. The airship patrol was much like the lifeboat service or a fire-brigade in the metropolis: its work was never ended. Beyond the ordinary routine there were emergency calls at any hour of the day or night.
"All ready?" asked the lieutenant.
He raised his hand. The motor began to purr, the swiftly revolving propeller churning up a cloud of dust that speedily rose as high as the recently vacated shed. The assistants, holding on to the restraining ropes, awaited the signal.
Barcroft lowered his hand smartly. With a motion not unlike that of a lift suddenly starting to ascend, the Blimp shot vertically upwards, the drag of her propeller being just sufficient to counteract the light head wind.
Not until the altitude gauge registered two hundred feet did the airship begin to forge ahead. Gradually the motor controls were opened out until the din of the whirling propeller grew terrific. At fifty miles an hour, and with the huge gasbag quivering under the enormous wind pressure, the Blimp tore to the aid of the torpedoed cruiser.
Kirkwood, who was searching the vast expanse of sea with his binoculars, raised the voice-tube to his lips.
"Say, old man," he exclaimed. "The destroyers have nearly twenty miles' start of us. I can spot them."
"The 'Antipas' is out," remarked Barcroft with a chuckle. "Won't old Tressidar be in a tear if we beat her! We'll try it, anyway."
Anderson and Bell, although ignorant of the precise nature of No. 144A's mission, were keenly on the alert. No doubt, in that mysterious way that supposedly secret information spreads with incomprehensible rapidity, the news of the torpedoing of the "Tantalus" was common property in and around Trecurnow; but beyond giving Kirkwood a brief account of what had occurred, Barcroft had refrained from mentioning the matter to any one at the airship station.
Twenty minutes after leaving terra firma the Blimp had left Land's End on her starboard quarter. Just within the western horizon could be discerned the cluster of small islands and rocks comprising the Scillies. North and south wisps of smoke gave evidence that, U-boats notwithstanding, the British mercantile marine was still unperturbed, for liners and tramps were to be seen either making for or leaving the Bristol Channel and English Channel ports.
"Are we gaining, do you think?" inquired Barcroft.
"Don't know, Billy, my festive," replied his second-in-command. "We seem to be overhauling the four older destroyers, but the 'Antipas' is a slipper. It's this head wind that's doing us in the eye."
The Blimp had struck a "rough patch." Tricky air currents, requiring all Barcroft's skill to counteract, made her plunge and yaw in a most erratic manner. At one moment the fuselage would be shooting ahead in practically a straight line, while overhead the gas envelope would be swaying from side to side like an ungainly pendulum; at another, the suspended car would be rearing and plunging like a dinghy rowed against short, steep seas; the while the breeze was whistling through the network of tensioned wires, the shrieking of the wind being audible even above the bass hum of the propeller and the noisy pulsations of the open exhaust.
Five hundred feet below the sea looked as calm as a mill-pond. Away to the west'ard patches of fog rendered observation a spasmodic business. Occasionally the horizon would be clearly visible, while a few minutes later a bank of thin vapour would form and blot out everything beneath it.
"There's the 'Tantalus'—a couple of points on our port bow!" exclaimed Kirkwood. "She's still afloat, then.... By Jove! She has a list."
Barcroft gave the Blimp the necessary amount of helm to bring her nose pointing directly for the painfully crawling cruiser.
"She's got it properly in the neck," he admitted. "We're gaining a bit, I think (his anxiety to beat 'Antipas' was almost an obsession). I can fancy Old Tress jumping about on the bridge like a cat on hot bricks, and working the engine-room johnnies like billy-ho."
"The wind's dropping; that's why we're gaining," said Kirkwood. "It's petrol motor versus turbine now, and let the best craft win. ...Hullo! the cruiser's opened fire again. Billy, my lad, we look like strafing that U-boat. Fritz is getting much too rash: he wants correcting."
"Stand by!" ordered Barcroft, addressing the aerial torpedo man through the voice-tube.
"Ay, ay, sir!" replied Anderson confidently. Then, bringing the tube into the nearest possible position to the horizontal, he carefully placed a sixty-pound missile into the breech, trained the weapon downwards, and stood by with his hand resting lightly upon the firing lever.
"All correct, sir," he reported.
Maintaining her former altitude the Blimp passed immediately above the badly listing "Tantalus," the crew of which raised a mighty cheer. The faint echoes of the true British greeting were wafted to the airship like a gentle murmur, in spite of the noise of the motor. Barcroft acknowledged the cheering with a wave of his hand, then, knitting his brows and compressing his lips, he centred all his attention upon the grim work that was about to be done.
Presently his eyes glittered with the light of battle, Three miles astern of the cruiser, and almost in the frothy wake of her labouring propeller, could be discerned an elongated, shadowy form, showing faintly against the greenish grey expanse of water. It was the U-boat running under the surface.
"Confound it!" ejaculated the lieutenant, as a dark grey swiftly moving vessel zig-zagged towards the spot where the U-boat's periscopes were last seen. "The old 'Antipas' is going to spoil my game."
A violent upheaval of foam, followed by a muffled detonation, announced that the destroyer had exploded a depth charge.
"You'll have to be a jolly sight more careful, Tressidar, old boy," soliloquised Barcroft. "You'll be blowing up the stern of your old hooker if you don't mind.... Ah! I thought so. You've missed your bird this time. Now, for goodness' sake fade away and let me have a look in."
"How's that?" morsed the wireless, as the operator of the "Antipas" sought advice and guidance from the Blimp.
"Missed!" replied the airship's wireless laconically. "If you can't do better than that, push off. You're in our light."
Ronald Tressidar, lieutenant-commander of the "Antipas," was nothing if not a sportsman. First upon the scene he had done his level best to send the U-boat to Davy Jones; failing at the first attempt, and not knowing the direction taken by the submerged pirate, he was not one to fail to recognise that the Blimp was better adapted to the task than the destroyer.
"Good luck!" flashed the aerial message from the "Antipas," as she steadied her helm and dashed away from the scene of her futile efforts.
The dark shadow was twisting and turning. The U-boat had dived so deeply that, viewed from the airship, she could hardly be distinguished from the water. It was enough for Barcroft: once on the trail it was a rare occurrence for him to be put off the scent when it came to Fritz hunting.
"Set to twenty fathoms!" he ordered.
"Twenty fathoms, sir!" replied Anderson, as he manipulated the fuse-timing that would allow the aerial torpedo to sink to the stated depth before detonating.
In his former seaplane career Barcroft had bombed his various objectives with uncanny precision. Good luck and sound judgment combined to make him a past master in the art of "getting there." But in aerial torpedo work against a submerged object a new factor had arisen—the effect of refraction. Unless a bomb-dropping machine—be it airship or seaplane—is directly over its objective, due allowance must be made for the deceptive qualities of air and water in conjunction. A simple experiment will easily show this. Take a bowl of water and place in it an object heavier than water—for example, a penny. Stand immediately over the bowl, and with a long rod attempt to "spear" the coin. Unless one's hand be wobbly the task will be easy enough. Next, take up a position so that an imaginary line from the eye to the penny forms an angle of about forty-five degrees with the horizontal. Repeat the thrusting operation and the coin will be missed handsomely, while the rod will appear to be sharply bent from the point where it enters the water.
Down to two hundred feet dropped the Blimp. The loss of altitude diminished the visibility of the presence of her prey, but there was just enough indication of the presence of the submerged submarine to enable Barcroft to risk a shot.
The motor was throttled down. Flying slowly and almost dead in the eye of the wind the airship was keeping pace with her blinded antagonist. It was like a keen-eyed hawk hovering over a stream and waiting to pounce upon an all unsuspecting fish.
Leaning over the side of the fuselage, Barcroft awaited the crucial moment. Then he raised his hand in a peremptory and unmistakable manner.
Instantly Anderson thrust down the firing lever. With a hiss of compressed air being released the powerful missile sped on its way, its course being clearly visible to the watchers from above.
A slight splash marked the torpedo's impact with the surface of the sea. Then, after a seemingly interminable wait, a dome-shaped mass of water was lifted bodily upwards, breaking and falling back in a smother of foam.
"Bon voyage, Fritz!" exclaimed Kirkwood.