"Perhaps they'll send a diver down to report."
"Not before daylight," declared Cain. "And then, if I am any judge of the weather, it'll be too choppy for that."
For some minutes every one kept silent. Although the watch below were almost overwhelmed with curiosity to know what had occurred, the captain gave strict orders that no conversation was to be permitted.
He was confident enough: Pengelly was showing signs of nervousness. Submarine work was not in his line. He was good enough for surface work—in fact, he was a good seaman—but he lacked the cold, calculating and resourceful courage of his chief.
"What's that?" he ejaculated, as a dull rasping sound penetrated the hull of the submarine, "They're sweeping for us."
"Shut up!" exclaimed Captain Cain sternly. The grinding noise continued for fifteen long-drawn-out seconds. Then it ceased as abruptly as it had commenced. Shortly afterwards, the muffled thud of the destroyer's engines were heard, loud at first then gradually diminishing.
"She's off," declared Captain Cain. "What we heard just now was the sinker [1] of a mark-buoy. She's probably making for Falmouth for shelter—or else under the lee of Lundy. They've done us out of a comfortable berth, Pengelly; we've got to shift."
"Now?" asked Pengelly dubiously.
"Not until an hour before high water," decided the other. "We'll break surface and drift, using our engines only if absolutely necessary. With the set of the flood tide we ought to be swept through the Sound midway between Godrevy Island and the Stones. There's a minimum of fifty feet at high water."
"How about the lighthouse-keepers?" objected Pengelly. "Ten to one they've been warned."