When he could trust himself to speak Hal Hastings addressed the naval officer.

"I think Mr. Benson and myself understand, sir, how it happened that this damage was done. There are extra parts in the repair kit. In twenty minutes, sir, I think we can have the engines running smoothly once more."

The naval officer was wise enough not to press the questioning further just then. Instead, he went on deck.

Working like beavers, and with the a.s.sistance of others standing about, Jack and Hal had the piston replaced and all the other parts in place within fifteen minutes. Then, once more, Hal turned on the gasoline, set the ignition, and watched.

The engine ran as smoothly as ever.

"There won't be any more trouble, unless someone is turned loose here with files and a blast lamp," p.r.o.nounced Hal. Then he and his chum sought the deck, to report to the officer in charge.

"You think we're in running order, now?" asked that officer.

"If you give the speed-ahead signal, sir, I think you'll feel as though you had a live engine under your deck," Hal a.s.sured him.

The signal was given, the "Pollard" immediately responding. She cut a wide circle, at good speed, returning to her former position, where the propellers were stopped.

"You suspect your own machinist, who was aboard?" asked the naval officer, in a low tone, of the submarine boys.

"If you'll pardon our not answering directly, sir," Captain Jack replied, "we want to have more than suspicions before we make a very energetic report on this strange accident. But we shall not be asleep, sir, in the matter of finding out. Then we shall make a full report to Mr. Mayhew."

"Success to you-and vigilance!" muttered the naval officer.

The gunboat's cutter came alongside, transferring Jack and Hal back to the "Farnum."

Hal went directly below to the engine room.

"You fixed the trouble with the 'Pollard'?" demanded Eph Somers, eagerly.

"Yes," Hal admitted.

"What was wrong?"

"Why, I don't know as I'd want to commit myself in too offhand a way,"

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 a.s.sented, 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."

Word was immediately pa.s.sed below, and all the cadets of the engineer division came tumbling up.

To these, who had been in the engine room constantly for hours, the cool wind blowing across the deck was highly agreeable.

For the speed dash Captain Jack Benson had again taken command. He pa.s.sed word below to Eph Somers to take the wheel in the conning tower.

Eph, therefore, came up with the last of the cadets from below. In the excitement of the pending race it had not been noticed by any of the submarine boys that Williamson was already on deck, aft. That left Sam Truax below in sole possession of the boat's engine quarters.

The gunboat now fell a little behind, leaving the two submarines some four hundred yards apart, but as nearly as possible on a line.

"Look at the crowd over on the 'Pollard's' decks," muttered Hal. "They're all Navy folks over there."

"And they mean to beat such plain 'dubs' as they must consider us,"

laughed Captain Jack, in an undertone.

"Will they beat us, though?" grinned Hal Hastings. "You and I, Jack, happen to know that the 'Farnum' is a bit the faster boat by rights."

Suddenly the signal broke out from the gunboat.

"Race her, Eph!" shouted Captain Jack.

"Aye, aye, sir!"

Eph Somers's right hand caught at the speed signals beside the wheel. He called for all speed, the bell jangling merrily in the engine room.

A little cheer of excitement went up from the cadets aboard the "Farnum"

as that craft shot ahead over the waters. The cadets were catching the thrill of what was virtually a race. At the same time, though, these midshipmen could not help feeling a good deal of interest in the success of the "Pollard," which was manned wholly by representatives of the Navy.

In the first three minutes the "Farnum" stole gradually, though slowly, ahead of the "Pollard." Then, to the disgust of all three of the submarine boys, the other craft was seen to be gaining. Before long the "Pollard"

had the lead, and looked likely to increase it. Already gleeful cheers were rising from the all-Navy crowd on the deck of the other submarine.

Behind the racers sped the "Hudson," keeping just far enough behind to be able to observe everything without interfering with either torpedo craft.

From looking at the "Pollard" Captain Jack glanced down at the water. His own boat's bows seemed to be cutting the water at a fast gait. The young skipper, knowing what he knew about both boats, could not understand this losing to the other craft.

"The Navy men must know a few tricks with engines that we haven't guessed," he observed, anxiously, to young Hastings.

"I don't know what it can be, then," murmured Hal, uneasily. "There aren't so confusingly many parts to a six-cylinder gasoline motor. They aren't hard engines to run. More depends on the engine itself than on the engineer."

"But look over there," returned Captain Jack Benson. "You see the 'Pollard' taking the wind out of our teeth, don't you?"

"Yes," Hal admitted, looking more puzzled.

"Do you think our engines are doing the top-notch of their best?" asked Benson.