"Yes; owing to their ability to make the trip under water, and taking advantage of the darkness, it is sometimes the case that they get through without being entangled in the nets," he replied.
"But how do the ships that sail along the Channel get through?" asked Alfred.
"That is just what I was referring to when I spoke of safety outlets. At a certain point there is an opening through the nets at one side, through which vessels can pass into the line between the two wire cordons. The opening in the other line of nets is not directly opposite, but a mile or so off to one side, so that in order to get to the opening in the other nets, it is necessary for the ship to sail along in the safety zone between the two nets, and make a turn at right angles to get out through the second opening. That method has been found to be most effective, and is called the safety lane," responded the captain.
They were now in or near the most widely traveled part of the ocean on the western front of the continent. Thousands of ships pass and repass that zone which reaches from the southern part of Ireland to the western coast of France, and it was remarkable that the submarine was able to move along up to this time on the surface without being detected.
Before the sun had gone down that night, however, they were compelled to submerge twice, and then the mantle of night shrouded the vessel and it moved along with more boldness. On this the fourth night of captivity, they were not locked in their prison.
"I cannot account for it," said the captain. "Possibly the commander has some little human sympathy left, and does not want to drown us like rats in a cage."
Neither the captain nor the boys slept much that night. They were too much occupied with constantly watching the manoeuvers necessary on the part of the commander and his crew to prevent detection as they passed up the Channel.
"I have spent years on the Channel as a navigating officer and in charge of various types of ships in the merchant service, as well as on our own naval vessels, and I know, probably, better than the lieutenant in charge of the submarine, what the dangers are. It is my belief that the lieutenant has come over this course before, and probably knows a safe, or measurably safe route, and has taken the chances of returning, but no one, however skilful a navigator he may be, can be sure of making exactly the same course twice. The tides may be against him; he may be out of his reckonings hundreds of feet, and that is too big a margin, where a hundred feet in width is the limit through which his vessel may pass in safety."
The captain thus, in general terms, set forth the perils of the route that the commander of the submarine had taken, and stated also, very plainly, that they must now be prepared to meet the greatest of all dangers. Sleep, therefore, could not be considered.
The long and weary night at last came to an end, and the appetizing odors of the morning meal were wafted to them. Their toilets were exceedingly simple affairs, a small cake of soap, warm water, and a long towel serving for the three. They had no trouble in dressing, for their clothing had not been removed. They were obliged to dispense with the bath, for, although all these boats are provided with comforts of that kind, none of them was available to the captain and the boys, and they did not ask that any privileges be extended to them.