"Yes, sir," replied both lads.
"Very well. Is there anything you would like me to do within the bounds of reason?"
"Could we communicate with our parents?" asked Ross.
"No," replied Schwalbe decisively. "There are strong objections. And, while I am on the subject, should you fall in with the crews of destroyed ships you are strictly forbidden to communicate with them either by word or gesture. That will be a punishable offence of the second degree. Anything more?"
"My friend has had a nasty knock on the head," said Trefusis. "Have you a doctor on board?"
Again Kapitan Schwalbe smiled broadly.
"No," he replied. "There is no need. Cases of illness must wait till we return to port. The only injuries we are likely to sustain would put us beyond all medical aid. But several of the men are fairly skilled in rough surgery, so I will——"
"Vessel on the port bow, sir; she's showing no lights," announced a voice.
"All hands to stations!" ordered the skipper.
"Down below with you!" hissed the petty officer, who during the interview had stood rigidly at attention at two paces to the rear of his charges.
Already the hitherto recumbent men were alert. Quickly, yet in order, they disappeared down the fore hatchway, and amongst them were Ross and Vernon.
The officers had taken their places inside the shelter of the conning-tower. Everything was battened down from within, and with a gentle purr the electric motors were set in motion, while at the same time water ballast was admitted into the trimming-tanks.
Swift and stealthy had been their preparations, but the presence of the submarine was betrayed by the phosphorescent swirl of the water caused by the churning of the twin propellers as she slipped beneath the surface.
Twenty seconds later a swift vessel that looked suspiciously like a trawler, although her speed belied her, tore over the place where U75 had disappeared. Bare inches only separated the top of the latter's conning-tower from the massive keel plates of the craft that had all but accomplished its mission.
The watch-dogs of the British Navy were at work.
CHAPTER VI. The Tramp
Like a startled hare the unterseeboot fled for shelter. Not until she reached a depth of fifteen fathoms did she check her diagonally downward course. At intervals a dull booming, audible above the rattle of the motors, proclaimed the unpleasant fact that her antagonist was circling around the spot marked by the phosphorescent swirl and the iridescence of escaped oil, and was firing explosive grapnels in the hope of ripping open the U-boat's hull.
Kapitan Schwalbe, looking very grey in the artificial light, was standing behind the quartermaster. His hands were clenched in momentary apprehension. Beads of perspiration stood out upon his forehead. He was experiencing a foretaste of the torment of the lost.
As a submarine officer of the Imperial German Navy he was a failure. Only sheer luck had hitherto saved him from the fate that had overtaken scores of his brother officers in that branch of the service. Skilled as he was in the handling of a huge liner, he lacked the iron nerve that is essential to the man who has to risk his life in a steel box that, in ninety-nine cases out of a hundred, offers no means of escape in the event of a catastrophe.
Yet he had to do his duty, notwithstanding his utter distaste for submarine work. He had had no option. The officers of the British Navy volunteer for submarine duties; those of the German Navy are simply told off whether they want to or not.
The nerve-racking work was beginning to tell upon him. His orders condemned him to a forlorn hope, for the English Channel was known to be a death-trap for the under-sea blockaders. The sight of a trawler filled him with feelings akin to terror. The possibility, nay probability, of a merchantman carrying guns made him approach his intended prey with the utmost caution; yet, as he had remarked to Ross Trefusis, he had never torpedoed any vessel flying the red ensign without giving her warning.
But it was not chivalry that prompted Schwalbe to act with consideration. Had he been untrammelled he would have sent his prey to the bottom without compunction, for he had all the brutal instincts of the kultured Hun. It was a superstitious fear that held his frightfulness in check—a presentiment based upon the Mosaic Law, an eye for an eye and a tooth for a tooth.
Having placed a considerable distance between him and his attacker, Kapitan Schwalbe ordered the electric motors to be stopped. The ballast tanks were "blown", and cautiously U75 rose to the surface.
It was the best course open to her. The depth of the water was much too great to allow her to rest on the bed of the sea. On the other hand, in order to keep submerged, the motors would have to be in motion. No one knew better than Schwalbe that the British patrol-boats would be in a position to locate with uncanny certitude the presence of their quarry, unless the strictest silence were maintained by the fugitive.
So, ready to dive at the first alarm, U75 floated awash until such times as were considered favourable for getting under way. Decidedly this part of the English Channel was, for the time being at least, unhealthy; and Kapitan Schwalbe resolved to make for the Bristol Channel, where the dangers of being destroyed by modern mosquitoes were more remote.
Meanwhile Ross and Vernon had been sent back to the quarters in the alley-way, by the side of the motor-room. Not knowing the reason for the U-boat's sudden submergence, and consequently unaware of the danger that threatened her, they formed the erroneous impression that the submarine was about to attack.
"The old fellow gave us a pretty straight tip," remarked Vernon, when the chums found themselves alone. "All the same, I vote we get out of it at the first opportunity, favourable or otherwise."
"'Ssh," whispered Ross. "Someone might be listening. I don't see how you propose to clear out, though."
"We were on deck just now."
"We were," agreed Trefusis.
"It was fairly dark. All the men up for'ard were lying down. It would have been an easy matter to have dived overboard and swum for it, if we hadn't been twenty miles or more from land."
"There was a bright look-out kept, all the same," objected Ross. "And I wouldn't mind saying that if the submarine were closer inshore, getting a supply of petrol, for example, we should be closely watched. All the same, I'm with you if we get the ghost of a chance. But it's a rummy affair altogether. Fancy that chap knowing our names and the rank of our respective fathers."
"Ramblethorne must have told him that," said Vernon.
"I suppose so; but for what reason? By Jove, if we get out of this mess all right, we'll have something to talk about—having been prisoners on a German submarine!"
The lads were not allowed on deck again that night. Acting upon Haye's suggestion they "turned in", and slept fitfully until awakened by the noise of the watch being relieved.
The seaman, Hans Koppe, brought them their breakfast. The meal consisted of fish, coffee, and the usual black bread. By this time the captives had practically recovered from the effects of the injection. Haye's head was still painful, although the headache had left him.
They ate with avidity, owing possibly to the atmosphere of the confined space, which was highly charged with oxygen.
"What is the Captain's name?" asked Ross, when the man came to remove the breakfast things.
The sailor told him.
"Where are we now?" enquired Vernon.
The man winked solemnly.
"Afloat," he replied. "Be content with that."
Just then there were unmistakable signs of activity on the part of the submarine crew. Several men hurried along the alley-way, each with a set purpose. They paid little heed to the Englanders as they passed.