"You do not understand," exclaimed Schwalbe. "We are at war. A blockade has been declared upon the British Islands. If, after full warning, merchantmen persist in taking the risk, it is their look-out, not mine. However, to return to a more personal matter: having been saddled with you, I must endure your presence. You will be well fed, as far as the resources at our command will allow. You will be free to go wherever you wish on board, with the exception of the conning-tower, motor- and torpedo-rooms. I am not ungrateful, for my brother, who had the misfortune to be in the
"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.