replied Hal, slowly, as though thinking.

“What appeared to be at the bottom of the trouble?”

“Why, it _may_ have been that one of the naval machinists, not
understanding our engines any too well, allowed one of the pistons to get
overheated, and then resorted to filing,” Hal replied.

“What? Overheat a piston, and then try to correct it with a file?” cried
young Somers, disgustedly. “The crazy blacksmith! He ought to be set to
shoeing snails—that’s all he’s fit for.”

“It looks that way,” Hal assented, smiling.

Artful, clever Hal! He had carried it all off so coolly and naturally that
Sam Truax, who had been closely studying Hastings’s face from the
background, was wholly deceived.

“This fellow, Hastings, isn’t as smart as I had thought him,” muttered
Truax, to himself.

The interrupted cruise now proceeded, the parent vessel signaling for a
temporary speed of sixteen knots in order to make up for lost time.

Twenty minutes later came the signal from the “Hudson:”

“At the command, the submarines will dash ahead at full speed, each making
its best time. During this trial, which will end at the firing of a gun
from the parent vessel, all cadets will be on deck.”