CHAPTER XI
Caught in the Net
Presently the powerful night-glasses revealed the misty outlines of a large two-funnelled craft slowly making her way in a southerly direction, the while signalling steadily, pausing only to receive an answering message from one of the German patrols.
Then, with all lights screened, came a pair of lean destroyers, zigzagging their way through the mine-field. After a while they steadied on their respective helms. Unless they altered course, they would pass at a distance not less than five cable-lengths from the lurking submarine.
"One of their strafed raiders coming here to roost for a dead cert," quoth the Hon. Derek. "Hands to action-stations, Mr. Macquare. I mean to let that chap pilot me through the mine-field, and, with luck, I'll return evil for good by putting a torpedo into him."
The two destroyers passed without sighting the British submarine. They were emitting dense columns of smoke that wafted over R19's deck as they steamed by. Two deductions were to be drawn from that circumstance. The boats were short of steam coal, which was a most cheerful bit of information. Also, from the fact that they were burning coal and not oil fuel, they were not by any means of the latest type of German torpedo craft.
Presently the nearmost destroyer put her helm hard over and circled away from the submarine. Not until she was pointing in exactly the opposite direction to the one she had been following did she steady and slow down. Her consort still carried on until she had passed the approaching armed merchantman. Then she, too, flung about.
Preceded and followed by her escort, the returning raider (for Stockdale's surmise was correct) steamed past at a rate of about five knots. It would have been a spendid opportunity for R19 to get home three torpedoes with mathematical precision, but reluctantly the Lieutenant-Commander stayed his hand. It was tantalizing but the greater issue was not to be lost sight of.
Under electrical motive power, for it was too risky to make use of even the well-muffled internal-combustion engines, R19 fell in at the tail of the procession, keeping at a distance of four cable-lengths astern of the rearmost destroyer.
Luck was in her favour, for not only was the night very dark, but the eddying clouds of smoke from the German vessels' funnels were frequently sweeping over the submarine, thus making a most effectual screen to her movements, while with her slow speed R19 did not show the "bone in her mouth"—the phosphorescent bow wave that at any high rate of speed would inevitably betray her position.
Both periscopes were "housed", and the boat prepared to dive at an instant's notice.
For a full quarter of a mile the course was due south, until, at a flashing-signal from the leading torpedo-boat, the big German starboarded her helm, and steered almost at right angles to her former direction. R19's officers noticed that the rearmost destroyer made no attempt to alter helm until she gained the position where the armed merchantman had turned. Evidently the "gateway" through the mine-field was narrow, and permitted no liberties.
As the following destroyer turned she flashed out a signal, to which a distant vessel replied. The next instant the concentrated rays of a dozen search-lights swept the surface of the water.
Down dropped R19 to 20 feet. Her periscopes were raised until they projected but 18 inches above the surface. Until the crucial moment, Stockdale chose to keep the escort under observation.
Again the Hun vessels turned, this time to port, and were heading straight for the centre of the far-flung line of patrol boats and destroyers.
"We're through, I fancy!" exclaimed the Hon. Derek. Then: "Down to forty feet."
At that depth the submarine was immune from the danger of being stove in, even by the keel of the heaviest battleship afloat. For the rest of the distance, until the last of the patrolling craft was left astern, the submarine had to depend upon direction by listening to the thresh of the Hun torpedo-boats' propellers.
The raider and her escorts were now increasing speed, another indication that the danger of the mine-field was a thing of the past. Before long R19, in her efforts to keep up with her hostile guides, was pushing ahead at fourteen knots—a rate sufficient to raise an ominous swirl upon the placid surface.
The while Macquare and the Sub were working out the course for future reference, noting the varying compass bearings and the distance run between alterations of helm. Knowing the exact spot where the second channel began, it would be a relatively simple matter to "plot out" the secret channel on the chart for use on the return run—if R19 were fortunate enough to leave the Baltic. In order to check each other's calculations the Lieutenant made his readings on a magnetic compass, while the Sub used the gyro-compass, which, unaffected by deviation and variation, enabled the navigator to obtain his knowledge of direction without having to take into consideration half a dozen intricate but important influences to which the magnetic instrument is subjected.
Presently, finding the pace too hot, the Hon. Derek gave orders for speed to be reduced to five knots. The returning raider had played her part as far as R19 was concerned, and, as a reward—although Stockdale would have willed it otherwise—she was rapidly drawing out of torpedo range. Even if the submarine dared to risk letting fly a couple of torpedoes, the possibility of hitting a vessel stern-on was rather remote, while the presence of a hostile craft inside their mine-field would at once be revealed to the German patrol-boats.
A faint rasping metallic sound caused both officers to look up from their respective tasks. It was the unmistakable noise of meshed wire grating along the submarine's side. Then, with a decided jerk, the vessel's way was checked. Under the impulse of her propellers she tilted nose downwards, the while the disconcerting sound of the flexible wire grinding against her was growing more and more in volume.
The artificer in charge of the motors acted promptly on the order to declutch and then reverse. Before her propellers had made a dozen revolutions the port-hand one, entangled in a remorselessly-tightening obstacle, slowed down, and then stopped dead.