Although his words were unintelligible in the roar of the elements, his outstretched hand gave an indication that the quarry was in sight. At an altitude of 3000 feet, and battling ineffectually with the gale, was a large Zeppelin—one of the "L" type. She was considerably down by the stern and manoeuvring badly. Two of her five propellers were motionless, while the action of her twin vertical rudders failed to keep her steady against the side-thrust of the remaining propellers. Steadily and surely she was being blown farther and farther away from her base.
Lieutenant-Commander Stockdale had already laid his plans. In calm weather diving would be almost useless as a means of concealment; but in the choppy seas now running the submarine could with advantage submerge until the crucial moment.
No alteration of the vessel's course was necessary. The Zeppelin was drifting almost straight towards her. Any slight deviation could be easily corrected by means of observation through the periscopes, for unless the air-ship turned and fled "down-wind"—an unlikely contingency—she could not help passing within effective range of the submarine's guns.
"Trim for diving."
The order was carried out with the utmost dispatch. With hardly a tremor the four guns, with their bulky mountings, sank into their "houses", the water-tight lids sliding automatically over the lowered weapons. The stanchions and rails fell as flat as did the walls of Jericho, but with far less noise and certainly no dust, although there was plenty of spray to atone for the deficiency. Ankle-deep in water, the men on deck waited until the submarine's platform was clear of the swirling foam, then they too bolted below. Clang went the water-tight hatches and R19 was little more than a hermetically-sealed cylinder packed with machinery, eighty odd human beings, and Flirt.
Alone in the conning-tower, the manhole of which, communicating with the interior of the hull, was left open, the Hon. Derek stood, his eyes fixed to the object-bowl of the periscope, on which the surrounding surface of the water was reproduced with absolute fidelity, marred only by a vertical and a horizontal line marked in degrees. In the middle part of the image, corresponding with the centre of the field of vision, a specially-constructed lens enlarged the view, enabling the observer to gauge the distance and the direction of the target with the greatest exactitude. Although there were voice-tubes and indicators at hand, the Lieutenant-Commander's attention was directed mainly upon the object-bowl. Consequently he shouted his orders to a petty officer, whose head, as he stood on the short steel ladder, was level with the floor of the conning-tower.
"Down to eighteen feet."
With an almost imperceptible movement, as the horizontal diving-planes were actuated, R19 slid beneath the waves, the while "pumping" or rising and falling vertically under the constant alteration of the pressure of the water above her. Momentarily the vision in the object-bowl dimmed and again recovered its normal clearness, as clouds of spray enveloped the tips of the exposed periscopes, almost immediately to vanish from the surface of the anti-moisture-treated glass.
In the confined space the noise of the well-running electric motors was deafening. The torpedo-men were in the present instance able to "stand easy", but the engine-room artificers and stokers, their moist faces glistening in the glare of the electric lights, were far from idle. The gun-crews, clustered round the hatchway ladders, ready to rush to their posts, were grimly silent, awaiting the order that would give them the chance to "strafe" a Hun gas-bag. Opportunities for "strafing" were few and far between in the British submarine service, not from inclination but from the absence of a suitable target; when a chance did occur the eager men were "all over it".
Standing immediately behind the petty officer stationed at the sound-receiving apparatus in a glass-encased compartment Sub-Lieutenant Fordyce noticed the man was listening intently, first at the right-hand disk then at the left. Then, turning his head, he regarded his officer with a puzzled air.