“Well, there probably is no more danger that way than there is in trying to get out of here to the west, where every German submarine available is on the lookout for us.”

“Besides,” urged Jack, “they will watch the entrance to the Kiel canal less closely, because they would not dream of an attempt to force its passage.”

“There is some truth in that, too,” said Lord Hastings. “Well, the Kiel canal be it then.”

Both lads were jubilant, and they could not contain themselves, but expressed their delight with loud “hurrahs” and by tossing their caps in the air.

So it came to pass that the D-16 laid herself out on a course for the Kiel canal, the waterway which the Germans had constructed at such great expense, that her fleet in the North Sea and her fleet in the Baltic might ever be in touch with one another.

An attempted passage of the Kiel canal by a hostile ship or ships had been considered out of the question by all naval authorities. Such an attempt, it was claimed, would be too foolhardy and would be bound to end in destruction.

Nevertheless, Lord Hastings, while realizing all this, was not the man to turn from a purpose once he had made up his mind. He realized the full danger of the situation much more than did Frank or Jack, who, carried away by the opportunity of participating in what would be one of the greatest naval ventures of history, had at once lost sight of all possible danger.

Deep, deep down in the sea the D-16 made her way from the harbor of Heligoland, diving far beneath the mines that protected the German fortifications. And in her wake she left three sunken German ships of war and another so badly damaged that she would be out of commission for many months.

“I am willing to bet,” said Frank, “that the Germans either lay the raid to internal troubles or else claim that a British submarine flotilla of at least 20 vessels participated.”

“Right you are,” agreed Jack, “and they will probably add that the enemy was driven off with great loss, more than half their number being placed hors du combat.”