The Navy launch was dashing full speed ahead. But with no clue to follow, Darrin passed some anxious seconds. Should he follow on the course he had been taking, or should he shut off speed? In the dark there was a good chance that the submarine commander, if so minded, would be able to double and head back for shore.
Land lights were still visible from his position. Dave turned to estimate their distance.
"About six knots off shore," he concluded, half aloud.
"Sir?" questioned the corporal of marines, thinking the ensign was addressing him.
"I was just telling myself that we're about six knots off shore."
"Yes, sir," replied the corporal, saluting.
"Listen to me, you men who are near enough to hear. Your understanding of what is in my mind may help you the better to work with me on this job. Two launches are keeping with us, over the starboard, and I judge the nearer one to be about four knots off. Coxswain, use the lantern signal and ask who commands."
Soon Hardy discovered that, in order to make his signal visible at that distance, he would have to stand higher. Springing to the forward deck his signal was instantly understood on the other craft.
Dave, who had jumped up beside him, read the answer:
"Ensign Dalzell."